AABBSSTTRRAACCTT During the last decades, a variety of alloys has beenused in orthodontics to manufacture wires. The ortho-dontic clinician is called to select from a large numberof materials that meet the biomechanical require-ments of the clinical case to be treated. Mechanical properties of orthodontic wires areassessed by different laboratory tests, such as tensile,torsional, and bending tests. Although wire character-istics determined by such tests cannot be directlylinked with their clinical application, they provide abasis for useful comparisons. The "ideal" wire charac-teristics have been specified by a number of authors.However, each wire may be considered ideal or not,depending on the targeted clinical outcome on eachcase. The clinician should know the properties and bio-mechanical behavior of available wires in order tochoose the appropriate wire depending on the target-ed outcome in different orthodontic treatment phases. The aim of this literature review is to summarizeorthodontic wire properties and demonstrate theirclinical applications as shown by their general proper-ties. Stainless steel, cobalt-chromium, nickel-titanium,beta-titanium and multistranded wires are studied.Moreover, the so-called "aesthetic" wires arereviewed, as well as their potential developmentexpected in the near future.

KKeeyy wwoorrddss:: Orthodontic wires, mechanical properties,applicationsHell Orthod Rev 2011;14:45-66.Received: 31.03.2011 – Accepted: 10.05.2011

¶¶∂∂ƒƒππ§§∏∏ææ∏∏∆Ș ÙÂÏÂ˘Ù·›Â˜ ‰ÂηÂٛ˜ Ì›· ÔÈÎÈÏ›· ÎÚ·Ì¿ÙˆÓ ¤¯ÂȯÚËÛÈÌÔÔÈËı› ÛÙËÓ ÔÚıÔ‰ÔÓÙÈ΋ ÁÈ· ÙËÓ Î·Ù·Û΢‹Û˘ÚÌ¿ÙˆÓ. √ ÎÏÈÓÈÎfi˜ ÔÚıÔ‰ÔÓÙÈÎfi˜ ηÏÂ›Ù·È Ó· ÂÈ-ϤÍÂÈ ·fi ÙËÓ ÏËıÒÚ· ÙˆÓ ˘ÏÈÎÒÓ ÙÔ Î·Ù¿ÏÏËÏÔÔ˘ ÂÎÏËÚÒÓÂÈ ÙȘ ÂÌ‚ÈÔÌ˯·ÓÈΤ˜ ··ÈÙ‹ÛÂȘ Ù˘ÎÏÈÓÈ΋˜ ÂÚ›ÙˆÛ˘ Ô˘ ·ÓÙÈÌÂÙˆ›˙ÂÈ.√È Ì˯·ÓÈΤ˜ ȉÈfiÙËÙ˜ ÙˆÓ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓÚÔÛ‰ÈÔÚ›˙ÔÓÙ·È ·fi ‰È¿ÊÔÚÔ˘˜ ÂÚÁ·ÛÙËÚÈ·ÎÔ‡˜ÂϤÁ¯Ô˘˜, fiˆ˜ ÂϤÁ¯Ô˘˜ ÂÊÂÏ΢ÛÌÔ‡, ÛÙÚ¤„˘ ‹Î¿Ì„˘. ¶·ÚfiÏÔ Ô˘ Ù· ¯·Ú·ÎÙËÚÈÛÙÈο ÙˆÓ Û˘ÚÌ¿-ÙˆÓ Ô˘ ÚÔÛ‰ÈÔÚ›˙ÔÓÙ·È ·fi ÙÔ˘˜ ÂϤÁ¯Ô˘˜ ·˘ÙÔ‡˜‰ÂÓ ÌÔÚÔ‡Ó Ó· Û˘Û¯ÂÙÈÛÙÔ‡Ó ¿ÌÂÛ· Ì ÙËÓ ÎÏÈÓÈ΋ÂÊ·ÚÌÔÁ‹ ÙÔ˘˜, ·ÔÙÂÏÔ‡Ó ÙË ‚¿ÛË ÁÈ· ÙË ‰ÈÂÍ·ÁˆÁ‹¯Ú‹ÛÈÌˆÓ Û˘ÁÎÚ›ÛˆÓ. ∆· ¯·Ú·ÎÙËÚÈÛÙÈο ÙÔ˘ ''ȉ·ÓÈ-ÎÔ‡'' Û‡ÚÌ·ÙÔ˜ ¤¯Ô˘Ó ÚÔÛ‰ÈÔÚÈÛÙ› ·fi ‰È¿ÊÔÚÔ˘˜Û˘ÁÁÚ·Ê›˜. øÛÙfiÛÔ, ÙÔ Î¿ı ۇÚÌ· ÌÔÚ› Ó· ıˆ-ÚËı› ȉ·ÓÈÎfi ‹ ÌË ·Ó·ÏfiÁˆ˜ Ì ÙÔ ÎÏÈÓÈÎfi ·ÔÙ¤ÏÂ-ÛÌ· Ô˘ ÂȉÈÒÎÂÙ·È Û οı ÂÚ›ÙˆÛË. √ ÎÏÈÓÈÎfi˜È·ÙÚfi˜ ÔÊ›ÏÂÈ Ó· ÁÓˆÚ›˙ÂÈ ÙȘ ȉÈfiÙËÙ˜ Î·È ÙËÓ ÂÌ‚ÈÔ-Ì˯·ÓÈ΋ Û˘ÌÂÚÈÊÔÚ¿ ÙˆÓ ‰È·ı¤ÛÈÌˆÓ Û˘ÚÌ¿ÙˆÓÒÛÙ ӷ ÂÈϤÁÂÈ ÙÔ Î·Ù¿ÏÏËÏÔ Û‡ÚÌ· ·Ó¿ÏÔÁ· Ì ÙÔ·ÔÙ¤ÏÂÛÌ· Ô˘ ÂÈ˙ËÙ› ÛÙȘ ‰È¿ÊÔÚ˜ Ê¿ÛÂȘ Ù˘ÔÚıÔ‰ÔÓÙÈ΋˜ ıÂڷ›·˜. ∏ ‚È‚ÏÈÔÁÚ·ÊÈ΋ ·˘Ù‹ ·Ó·ÛÎfiËÛË ·ÔÛÎÔ› Ó··Ó·ÎÂÊ·Ï·ÈÒÛÂÈ ÙȘ ȉÈfiÙËÙ˜ ÙˆÓ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘Ú-Ì¿ÙˆÓ Î·È Ó· ηٷ‰Â›ÍÂÈ ÙȘ ÎÏÈÓÈΤ˜ ÂÊ·ÚÌÔÁ¤˜ ÙÔ˘˜,fiˆ˜ ·˘Ù¤˜ ˘·ÁÔÚ‡ÔÓÙ·È ·fi ÙȘ ÂÓ Á¤ÓÂÈ È‰ÈfiÙËÙ˜ÙÔ˘˜. ªÂÏÂÙÒÓÙ·È Ù· Û‡ÚÌ·Ù· ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚·,ÎÔ‚·ÏÙ›Ô˘-¯ÚˆÌ›Ô˘, ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘, ‚-ÙÈÙ·Ó›Ô˘ ηÈÙ· ÔχÎψӷ Û‡ÚÌ·Ù·. ∂›Û˘, ·ÚÔ˘ÛÈ¿˙ÔÓÙ·È Ù·ÏÂÁfiÌÂÓ· ''·ÈÛıËÙÈο'' Û‡ÚÌ·Ù· ηıÒ˜ Î·È ÔÈ ÚÔÔ-

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H 2011 ñ TOMO™ 14 ñ TEYXO™ 1 45

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1√‰ÔÓÙ›·ÙÚÔ˜, ªÂÙ·Ù˘¯È·Îfi˜ ºÔÈÙËÙ‹˜ √‰ÔÓÙÈ·ÙÚÈÎÒÓ µÈÔ¸ÏÈÎÒÓ, ∂ÚÁ·ÛÙ‹ÚÈÔ µ·ÛÈÎÒÓ ∂ÈÛÙËÌÒÓ, √‰ÔÓÙÈ·ÙÚÈ΋ ™¯ÔÏ‹, ∞ÚÈÛÙÔÙ¤ÏÂÈÔ ¶·ÓÂÈÛÙ‹ÌÈÔ £ÂÛÛ·ÏÔӛ΢.2√ÚıÔ‰ÔÓÙÈÎfi˜, ÀÔ„‹ÊÈÔ˜ ¢È‰¿ÎÙˆÚ ¶·ÓÂÈÛÙËÌ›Ô˘ µ¤ÚÓ˘, ∂Ï‚ÂÙ›·˜.3∞Ó·ÏËÚˆÙ‹˜ ∫·ıËÁËÙ‹˜, ∂ÚÁ·ÛÙ‹ÚÈÔ √ÚıÔ‰ÔÓÙÈ΋˜, √‰ÔÓÙÈ·ÙÚÈ΋ ™¯ÔÏ‹, ∞ÚÈÛÙÔÙ¤ÏÂÈÔ ¶·ÓÂÈÛÙ‹ÌÈÔ £ÂÛÛ·ÏÔӛ΢

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1Dentist, Postgraduate Student in Dental Biomaterials, Department of Basic Dental Sciences, School of Dentistry, Aristotle University ofThessaloniki, Greece.2Orthodontist, PhD candidate, University of Bern, Switzerland.3Associate Professor, Department of Orthodontics, School of Dentistry, Aristotle University of Thessaloniki, Greece.

π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires HELLENIC ORTHODONTIC REVIEW

46 HELLENIC ORTHODONTIC REVIEW 2011 ñ VOLUME 14 ñ ISSUE 1

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∫·Ù¿ ÙËÓ ÔÚıÔ‰ÔÓÙÈ΋ ıÂڷ›· ÂȉÈÒÎÂÙ·È Ë ÌÂٷΛÓË-ÛË ÙˆÓ ‰ÔÓÙÈÒÓ Û ÂÈı˘ÌËÙ‹ ı¤ÛË Û˘Ó‹ıˆ˜ Ì ÙËÓ¿ÛÎËÛË ‰˘Ó¿ÌÂˆÓ Û ·˘Ù¿. ∏ ȉ·ÓÈ΋ ‰‡Ó·ÌË Â›Ó·È ·˘Ù‹Ô˘ Ô‰ËÁ› Û ÁÚ‹ÁÔÚË ÌÂٷΛÓËÛË ¯ˆÚ›˜ Ó· ÚÔηÏ›‚Ï¿‚˜ ÛÙÔ˘˜ ÈÛÙÔ‡˜ ÙÔ˘ ÂÚÈÔ‰ÔÓÙ›Ô˘ Î·È Ù· ‰fiÓÙÈ·.¶·ÚfiÏÔ Ô˘ Â›Ó·È ‰‡ÛÎÔÏÔ Ó· ÚÔÛ‰ÈÔÚÈÛı› Ë ·ÎÚÈ‚‹˜ÙÈÌ‹ Ù˘ ȉ·ÓÈ΋˜ ‰‡Ó·Ì˘, ηıÒ˜ ˘ÂÈÛ¤Ú¯ÔÓÙ·È ‰È¿ÊÔ-ÚÔÈ ‚ÈÔÏÔÁÈÎÔ› Î·È ¿ÏÏÔÈ ·Ú¿ÁÔÓÙ˜, fiˆ˜ ÙÔ Â›‰Ô˜ Ù˘ÌÂٷΛÓËÛ˘ Î·È ÙÔ Ì¤ÁÂıÔ˜ ÙÔ˘ ‰ÔÓÙÈÔ‡ (Houston ηÈÛ˘Ó., 1996), ÔÈ ÔÚıÔ‰ÔÓÙÈΤ˜/ÔÚıÔ‰ÈΤ˜ ‰˘Ó¿ÌÂÈ˜Û˘Ó‹ıˆ˜ Î˘Ì·›ÓÔÓÙ·È Û ¤Ó· ‡ÚÔ˜ 0,15-5N (Shetty ηÈÛ˘Ó., 1994; Holberg Î·È Û˘Ó., 2008). ªÂϤÙ˜ ¤¯Ô˘Ó ‰Â›-ÍÂÈ ˆ˜ Ë ¿ÛÎËÛË ‹ÈˆÓ ‰˘Ó¿ÌÂˆÓ ·Ô‰›‰ÂÈ Ù· ηχÙÂ-Ú· ·ÔÙÂϤÛÌ·Ù· (Reitan, 1967; Van Leeuwen Î·È Û˘Ó.,2010). ∏ ¿ÛÎËÛË ¤ÓÙÔÓ˘ ‰‡Ó·Ì˘ Ô˘ ˘ÂÚ‚·›ÓÂÈ ÙËÓ·ÈÌ·ÙÈ΋ ›ÂÛË ÙˆÓ ·ÁÁ›ˆÓ Ô‰ËÁ› Û Ì›ˆÛË Ù˘ ΢ÙÙ·-ÚÈ΋˜ ‰Ú·ÛÙËÚÈfiÙËÙ·˜ ÛÙÔ˘˜ ÈÛÙÔ‡˜ ÙÔ˘ ÂÚÈÔ‰ÔÓÙ›Ô˘ ηÈÂÈ‚Ú¿‰˘ÓÛË ‹ ·‡ÛË Ù˘ ÌÂٷΛÓËÛ˘ ÙÔ˘Ï¿¯ÈÛÙÔÓ ÁÈ·ÔÚÈṲ̂ÓÔ ¯ÚÔÓÈÎfi ‰È¿ÛÙËÌ· (Leach Î·È Û˘Ó., 2001).∏ ‰˘Ó·ÙfiÙËÙ· ¿ÛÎËÛ˘ ‹ÈˆÓ ‰˘Ó¿ÌÂˆÓ Î·È Â›Ù¢Í˘ÌÂÁ·Ï‡ÙÂÚÔ˘ ‡ÚÔ˘˜ ÌÂÙ·ÎÈÓ‹ÛÂˆÓ ÌÂٷ͇ ÙˆÓ Û˘ÓÂ-‰ÚÈÒÓ Â›Ó·È ÛËÌ·ÓÙÈ΋ ÁÈ· ÙË ‚ÂÏÙ›ˆÛË Ù˘ ÔÈfiÙËÙ·˜ ηÈÙ˘ ·fi‰ÔÛ˘ Ù˘ ıÂڷ›·˜. √ ·ÚÈÔ˜ Û˘ÓÙÂÏÂÛÙ‹˜¿ÛÎËÛ˘ ‰˘Ó¿ÌÂˆÓ ÛÙ· ‰fiÓÙÈ· ηٿ ÙËÓ ÔÚıÔ‰ÔÓÙÈ΋ıÂڷ›· Ì ·Î›ÓËÙ˜ Û˘Û΢¤˜ Â›Ó·È ÙÔ ÔÚıÔ‰ÔÓÙÈÎfiÛ‡ÚÌ·. ∆Ô Û‡ÚÌ· ·ÂÏ¢ıÂÚÒÓÂÈ ÙËÓ ÂÓ¤ÚÁÂÈ· Ô˘ ·Ô-ıË·ÂÈ Î·Ù¿ ÙËÓ ÙÔÔı¤ÙËÛ‹ ÙÔ˘ ·ÛÎÒÓÙ·˜ ‰˘Ó¿ÌÂÈ˜Î·È ÚÔ¤˜ ÛÙ· ‰fiÓÙÈ· ̤ۈ ÙˆÓ Û˘Û΢ÒÓ Ô˘ ›ӷÈÙÔÔıÂÙË̤Ó˜ Û ·˘Ù¿ (Rudolph Î·È Û˘Ó., 2001). ™˘ÓÂ-Ò˜, Ë ÁÓÒÛË Ù˘ ÂÌ‚ÈÔÌ˯·ÓÈ΋˜ Û˘ÌÂÚÈÊÔÚ¿˜ ηÈÙˆÓ ÎÏÈÓÈÎÒÓ ÂÊ·ÚÌÔÁÒÓ ÙˆÓ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓÂ›Ó·È ··Ú·›ÙËÙË ÁÈ· ÙËÓ ·ÚÌÔÓÈ΋ ÂÎÙ¤ÏÂÛË ÙÔ˘ ۯ‰›Ô˘Ù˘ ıÂڷ›·˜.∏ ÚfiÔ‰Ô˜ Ô˘ ¤¯ÂÈ Û˘ÓÙÂÏÂÛÙ› ÙȘ ÙÂÏÂ˘Ù·›Â˜ ‰ÂηÂٛ˜ÛÙËÓ Ù¯ÓÔÏÔÁ›· ÙˆÓ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ ¤¯ÂÈ Ô‰Ë-Á‹ÛÂÈ Û ̛· ÛËÌ·ÓÙÈ΋ ÔÈÎÈÏ›· Û˘ÚÌ¿ÙˆÓ, Ô˘ ‰È·ı¤-ÙÔ˘Ó Â˘Ú‡ Ê¿ÛÌ· ȉÈÔًوÓ. ª¤¯ÚÈ ÙÔ 1930 fiÏ· Ù· ‰È·-ı¤ÛÈÌ· ÔÚıÔ‰ÔÓÙÈο Û‡ÚÌ·Ù· ‹Ù·Ó ηٷÛ΢·Ṳ̂ӷ·fi ¯Ú˘Ûfi. ™‹ÌÂÚ· Ù· Û‡ÚÌ·Ù· ·˘Ù¿ ‚Ú›ÛÎÔ˘Ó ÂÏ¿¯ÈÛÙË

IINNTTRROODDUUCCTTIIOONN

During orthodontic treatment, the aim is to move theteeth to a targeted position usually by applying forces tothem. An ideal force is the one that produces rapid toothmovement without damage to the teeth or periodontaltissues. Although it is difficult to precisely determine thevalue of the ideal force since different biological and otherfactors such as the type of movement and tooth sizeshould be considered (Houston et al., 1996), orthodon-tic/orthopedic forces usually range from 01.5-5N (Shettyet al., 1994; Holberg et al., 2008). Studies have shown thatthe application of lower forces produces the optimalresults. Application of excessive force exceeding vascularblood pressure reduces cellular activity in periodontal tis-sues and slows down or stops tooth movement at leastfor a period in time (Leach et al., 2001).The ability to apply lower forces and achieve a widerrange of movements between sessions is of major impor-tance to improve both the quality and performance oftreatment. The primary method to apply forces to theteeth during orthodontic treatment using fixed appliancesis the orthodontic wire. The wire releases the energystored upon its placement by applying forces and torqueto the teeth through the appliances placed on them(Rudolph et al., 2001). Therefore, knowledge of the bio-mechanical behavior and clinical applications of ortho-dontic wires is required to properly apply the treatmentplan. The progress made in recent decades in orthodontic withtechnology has resulted in a large variety of wires with awide range of properties. Up until 1930 all orthodonticwires available were made of gold. Nowadays, these wiresare rarely used mostly due to their high cost compared tothat of alternatives. The use of stainless steel to produceorthodontic wires was introduced in 1929. Stainless steelquickly gained popularity over gold due to its improvedmechanical properties and lower cost. Since then severalother alloys exhibiting particular properties, as required,have been introduced in clinical practice. These includecobalt-chromium, nickel-titanium, beta-titanium and mul-tistranded stainless steel wires.No wire is appropriate for all treatment stages and no wireis ideal. The clinician should consider a variety of wireparameters and characteristics as necessary. The selectionof an appropriate wire size and type for each treatmentstage may, in theory, lead to a reduced number and dura-tion of sessions, and possibly treatment as well, in caseswhere the wire acts throughout the time period betweenconsecutive sessions, thus resulting in a higher-quality andmore predictable treatment outcome.The properties of orthodontic wires are determined by dif-ferent types of laboratory tests investigating wire behav-ior in terms of tension, bending, and torsion (Kapila and

ÙÈΤ˜ ÂͤÏÈ͢ Ô˘ ·Ó·Ì¤ÓÔÓÙ·È ÛÙÔ ¿ÌÂÛÔ Ì¤ÏÏÔÓ.

§§¤¤ÍÍÂÂÈȘ̃ ÎÎÏÏÂÂÈȉ‰ÈÈ¿¿:: OÚıÔ‰ÔÓÙÈο Û‡ÚÌ·Ù·, Ì˯·ÓÈΤ˜ ȉÈfi-ÙËÙ˜, ÂÊ·ÚÌÔÁ¤˜∂ÏÏ √ÚıÔ‰ ∂Èı 2011;14:45-66.¶·ÚÂÏ‹ÊıË: 31.03.2011 – ŒÁÈÓ ‰ÂÎÙ‹: 10.05.2011

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H 2011 ñ TOMO™ 14 ñ TEYXO™ 1 47

¯Ú‹ÛË Î˘Ú›ˆ˜ ÏfiÁˆ ÙÔ˘ ÙÂÚ¿ÛÙÈÔ˘ ÎfiÛÙÔ˘˜ Û ۯ¤ÛË ÌÂÙȘ ÂÓ·ÏÏ·ÎÙÈΤ˜ ÂÈÏÔÁ¤˜. ∏ ¯Ú‹ÛË ÙÔ˘ ·ÓÔÍ›‰ˆÙÔ˘¯¿Ï˘‚· ÁÈ· ÙËÓ Î·Ù·Û΢‹ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓÚÔÙ¿ıËΠÙÔ 1929 Î·È ÁÚ‹ÁÔÚ· ¤ÁÈÓ ‰ËÌÔÊÈϤÛÙÂÚËÙÔ˘ ¯Ú˘ÛÔ‡ ÂÍ·ÈÙ›·˜ ÙˆÓ ‚ÂÏÙÈˆÌ¤ÓˆÓ Ì˯·ÓÈÎÒÓ È‰ÈÔ-Ù‹ÙˆÓ Î·È ÙÔ˘ ÌÈÎÚfiÙÂÚÔ˘ ÎfiÛÙÔ˘˜ ÙÔ˘. ∞fi ÙfiÙ ‰È¿ÊÔ-Ú· ¿ÏÏ· ÎÚ¿Ì·Ù· Ô˘ ÂÌÊ·Ó›˙Ô˘Ó Û˘ÁÎÂÎÚÈ̤Ó˜, ηٿÂÚ›ÙˆÛË, ÂÈı˘ÌËÙ¤˜ ȉÈfiÙËÙ˜ ¤¯Ô˘Ó ÂÈÛ·¯ı› ÛÙËÓÎÏÈÓÈ΋ Ú¿ÍË. ™Â ·˘Ù¿ ÂÚÈÏ·Ì‚¿ÓÔÓÙ·È Ù· ÎÚ¿Ì·Ù·ÎÔ‚·ÏÙ›Ô˘-¯ÚˆÌ›Ô˘, ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘, ‚-ÙÈÙ·Ó›Ô˘ Î·È Ù·ÔχÎψӷ Û‡ÚÌ·Ù· ·fi ·ÓÔÍ›‰ˆÙÔ ¯¿Ï˘‚·.∫·Ó¤Ó· Û‡ÚÌ· ‰ÂÓ Â›Ó·È Î·Ù¿ÏÏËÏÔ ÁÈ· fiÏ· Ù· ÛÙ¿‰È·Ù˘ ıÂڷ›·˜ Î·È Î·Ó¤Ó· Û‡ÚÌ· ‰ÂÓ Â›Ó·È È‰·ÓÈÎfi. √ ÎÏÈ-ÓÈÎfi˜ ı· Ú¤ÂÈ Ó· Ï·Ì‚¿ÓÂÈ ˘’ fi„ÈÓ ÙÔ˘ ÌÈ· ÔÈÎÈÏ›··Ú·Ì¤ÙÚˆÓ Î·È ¯·Ú·ÎÙËÚÈÛÙÈÎÒÓ ÙˆÓ Û˘ÚÌ¿ÙˆÓ ÛÂοı ÂÚ›ÙˆÛË. ∏ ÂÈÏÔÁ‹ ÙÔ˘ ηٿÏÏËÏÔ˘ ÌÂÁ¤ıÔ˘˜Î·È Ù‡Ô˘ Û‡ÚÌ·ÙÔ˜ ÁÈ· οı ÛÙ¿‰ÈÔ Ù˘ ıÂڷ›·˜ ÌÔ-Ú› ıˆÚËÙÈο Ó· Ô‰ËÁ‹ÛÂÈ Û Ì›ˆÛË ÙÔ˘ ·ÚÈıÌÔ‡ ηÈÙ˘ ‰È¿ÚÎÂÈ·˜ ÙˆÓ Û˘Ó‰ÚÈÒÓ, ·ÏÏ¿ Èı·ÓfiÓ Î·È Ù˘‰È¿ÚÎÂÈ·˜ Ù˘ ıÂڷ›·˜ Û ÂÚÈÙÒÛÂȘ Ô˘ ÙÔ Û‡ÚÌ·‰Ú· ÂÏÂÁ¯fiÌÂÓ· Û fiÏÔ ÙÔ ‰È¿ÛÙËÌ· ÌÂٷ͇ ‰È·‰Ô¯ÈÎÒÓÛ˘Ó‰ÚÈÒÓ Î·È ¤ÙÛÈ Ó· ηٷϋÍÂÈ Û ¤Ó· ÔÈÔÙÈÎfiÙÂÚÔ Î·ÈÂÚÈÛÛfiÙÂÚÔ ÚԂϤ„ÈÌÔ ıÂڷ¢ÙÈÎfi ·ÔÙ¤ÏÂÛÌ·.√È È‰ÈfiÙËÙ˜ ÙˆÓ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ ÚÔÛ‰ÈÔÚ›˙Ô-ÓÙ·È Ì ‰È¿ÊÔÚÔ˘˜ Ù‡Ô˘˜ ÂÚÁ·ÛÙËÚÈ·ÎÒÓ ÂϤÁ¯ˆÓ, Ô˘‰ÈÂÚ¢ÓÔ‡Ó ÙË Û˘ÌÂÚÈÊÔÚ¿ ÙˆÓ Û˘ÚÌ¿ÙˆÓ Û ÂÊÂÏ΢-ÛÌfi, Î¿Ì„Ë ‹ ÛÙÚ¤„Ë (Kapila Î·È Sachdeva, 1989).¶·ÚfiÏÔ Ô˘ ·˘ÙÔ› ÔÈ ¤ÏÂÁ¯ÔÈ ‰ÂÓ ÚÔÛÔÌÔÈÒÓÔ˘Ó Ï‹-Úˆ˜ ÙȘ ÎÏÈÓÈΤ˜ Û˘Óı‹Î˜ ÛÙȘ Ôԛ˜ ¯ÚËÛÈÌÔÔÈÔ‡ÓÙ·ÈÙ· Û‡ÚÌ·Ù·, ·Ú¤¯Ô˘Ó ÙË ‚¿ÛË ÁÈ· ÙËÓ Ú·ÁÌ·ÙÔÔ›ËÛËÛ˘ÁÎÚ›ÛÂˆÓ ÌÂٷ͇ ÙÔ˘˜. √È ¤ÏÂÁ¯ÔÈ Î¿Ì„ÂˆÓ ·Ú¤¯Ô˘ÓÔÚÈṲ̂Ó˜ ÏËÚÔÊÔڛ˜ ÁÈ· ÙË Û˘ÌÂÚÈÊÔÚ¿ ÙˆÓ Û˘Ú-Ì¿ÙˆÓ fiÙ·Ó ˘Ô‚¿ÏÏÔÓÙ·È Û ο̄ÂȘ 1˘ ‹ 2˘ Ù¿Í˘.ŸÌÔÈ·, Ù· ·ÔÙÂϤÛÌ·Ù· ·fi ÂϤÁ¯Ô˘˜ ÛÙÚ¤„˘ ·ÓÙÈη-ÙÔÙÚ›˙Ô˘Ó Û οÔÈÔ ‚·ıÌfi ÙË Û˘ÌÂÚÈÊÔÚ¿ ÙˆÓ Û˘Ú-Ì¿ÙˆÓ Î·Ù¿ ÙȘ ο̄ÂȘ 3˘ Ù¿Í˘. ¶Ú¤ÂÈ Ó· ÙÔÓÈÛÙ› ˆ˜Ô ÂÊÂÏ΢ÛÌfi˜, Ë Î¿Ì„Ë Î·È Ë ÛÙÚ¤„Ë Â›Ó·È ·fiÏ˘Ù· ‰È·-ÊÔÚÂÙÈΤ˜ ηٷÛÙ¿ÛÂȘ ÊfiÚÙÈÛ˘ Î·È ÂÍÂÙ¿˙Ô˘Ó, ·ÓÙ›ÛÙÔÈ-¯·, ‰È·ÊÔÚÂÙÈο ¯·Ú·ÎÙËÚÈÛÙÈο Ô˘ Û¯ÂÙ›˙ÔÓÙ·È Ì ÙËÓ·fi‰ÔÛË ÙˆÓ Û˘ÚÌ¿ÙˆÓ (Kusy Î·È Greenberg, 1981;Asgharnia Î·È Brantley, 1986). °È’ ·˘Ùfi Ù· ¯·Ú·ÎÙËÚÈÛÙÈ-ο ÙˆÓ Û˘ÚÌ¿ÙˆÓ Ô˘ ÚÔÛ‰ÈÔÚ›˙ÔÓÙ·È ·fi ·˘Ù¤˜ ÙȘÙÚÂȘ ηٷÛÙ¿ÛÂȘ ÊfiÚÙÈÛ˘ Ú¤ÂÈ Ó· ·ÍÈÔÏÔÁÔ‡ÓÙ·È·ÓÂÍ¿ÚÙËÙ·.

ÃÃ∞∞ƒƒ∞∞∫∫∆∆∏∏ƒƒππ™™∆∆ππ∫∫∞∞ ∆∆øø¡¡ ™™ÀÀƒƒªª∞∞∆∆øø¡¡ ªª∂∂ ∫∫§§ππ¡¡ππ∫∫∏∏™™∏∏ªª∞∞™™ππ∞∞

À¿Ú¯Ô˘Ó ‰È¿ÊÔÚ· ¯·Ú·ÎÙËÚÈÛÙÈο Ô˘ ıˆÚÔ‡ÓÙ·ÈÂÈı˘ÌËÙ¿ ÁÈ· ÙËÓ Î·Ï‹ Û˘ÌÂÚÈÊÔÚ¿ ÂÓfi˜ Û‡ÚÌ·ÙÔ˜

Sachdeva, 1989). Although these tests do not fully simu-late the clinical setting where wires are used, they providea basis for comparison of wires. Bending tests providesome information on wire behavior when they are sub-jected to 1st or 2nd order bends. Similarly, torsional testresults reflect, to a certain degree, wire behavior in 3rdorder bends. It should be noted that tension, bending, andtorsion are completely different stress states investigatingdifferent characteristics related with wire performance,respectively (Kusy and Greenberg, 1981; Asgharnia andBrantley, 1986). Therefore, wire characteristics determinedunder these three stress states should be assessed inde-pendently.

WWIIRREE CCHHAARRAACCTTEERRIISSTTIICCSS OOFF CCLLIINNIICCAALL RREELLEEVVAANNCCEE

There are different characteristics considered desirable fora wire’s good behavior depending on the clinical case,such as aesthetics, resiliency, elasticity, a large spring-back,low stiffness, high formability, high stored energy, bio-compatibility, and stability in use, low friction, and thecapability to be welded with biomechanical attachments(Kapila and Sachdeva, 1989; Kusy, 1997).The maximum spring-back (range) is also referred to asmaximum elasticity, range of deflection or range of acti-vation or working range, and it is the property relatedwith the ratio of yield strength to the modulus of elastic-ity of the material (YS/E). The yield strength is the stressrequired to obtain 0.2% deflection of the wire after it isunloaded. A large range of activation enables the clinicianto achieve larger activations resulting in the wire’sincreased working time (Ingram et al., 1986; Zufall andKusy, 2000a).Stiffness or load deflection rate is the force magnitudedelivered by an appliance and is proportional to the mod-ulus of elasticity (E) (Goldberg et al. 1983). Low wire stiff-ness provides the ability to apply lower forces, a more con-stant force overtime as the appliance experiences deacti-vation, and greater accuracy in applying a given force (Bur-stone and Goldberg, 1980).Formability is the specific property allowing to easily formthe wire without breaking it or significantly altering itscharacteristics. Stored energy or resilience is the property of a material tostore energy while deflected and produce this energywhile unloaded. This feature represents the work avail-able to move teeth.Biocompatibility (or biohostability) includes resistance tocorrosion and tissue tolerance to wire elements. Ideally,the wire should neither favor nor be a substrate for devel-oping microorganisms and allergies. The capability to be welded (or soldered) with biome-chanical attachments is important in wires and may beachieved through electric welding or by using a binding

π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires HELLENIC ORTHODONTIC REVIEW

48 HELLENIC ORTHODONTIC REVIEW 2011 ñ VOLUME 14 ñ ISSUE 1

·Ó¿ÏÔÁ· Ì ÙËÓ ÎÏÈÓÈ΋ ÂÚ›ÛÙ·ÛË, fiˆ˜ Ë ·ÈÛıËÙÈ΋, Ë·ÓıÂÎÙÈÎfiÙËÙ·, Ë ÂÏ·ÛÙÈÎfiÙËÙ·, ÙÔ ÌÂÁ¿ÏÔ Â‡ÚÔ˜ ÂÓÂÚÁÔ-Ô›ËÛ˘ (spring-back), Ë ÌÈÎÚ‹ ·Î·Ì„›·, Ë Î·Ï‹ ÈηÓfi-ÙËÙ· ‰È·ÌfiÚʈÛ˘, Ë ÈηÓfiÙËÙ· ·Ôı‹Î¢Û˘ ÌÂÁ¿Ï˘ÂÓ¤ÚÁÂÈ·˜, Ë ‚ÈÔÛ˘Ì‚·ÙfiÙËÙ· Î·È ÛÙ·ıÂÚfiÙËÙ· ηٿ Ù˯ڋÛË, Ë ¯·ÌËÏ‹ ÙÚÈ‚‹ Î·È Ë ‰˘Ó·ÙfiÙËÙ· Û˘ÁÎfiÏÏËÛ˘ÂÌ‚ÈÔÌ˯·ÓÈÎÒÓ ‚ÔËıËÌ¿ÙˆÓ (Kapila Î·È Sachdeva,1989; Kusy, 1997).∏ ̤ÁÈÛÙË ÂÏ·ÛÙÈ΋ ·Ú·ÌfiÚʈÛË (spring-back, range),Ë ÔÔ›· ›Û˘ ·Ó·Ê¤ÚÂÙ·È ˆ˜ ̤ÁÈÛÙË ÂÏ·ÛÙÈÎfiÙËÙ·,‡ÚÔ˜ ·Ú·ÌfiÚʈÛ˘ ‹ ‡ÚÔ˜ ÂÓÂÚÁÔÔ›ËÛ˘-ÂÚÁ·-Û›·˜, Â›Ó·È Ë È‰ÈfiÙËÙ· Ô˘ Û¯ÂÙ›˙ÂÙ·È Ì ÙËÓ ·Ó·ÏÔÁ›· ÙÔ˘ÔÚ›Ô˘ ‰È·ÚÚÔ‹˜ (yield strength) ÚÔ˜ ÙÔ Ì¤ÙÚÔ ÂÏ·ÛÙÈ-ÎfiÙËÙ·˜ (modulus of elasticity) ÙÔ˘ ˘ÏÈÎÔ‡ (YS/E). ŸÚÈԉȷÚÚÔ‹˜ Â›Ó·È ÙÔ Ì¤ÁÂıÔ˜ Ù¿Û˘ ÛÙÔ ÔÔ›Ô ÙÔ Û‡ÚÌ·ÌÂÙ¿ ÙËÓ ÂÎÊfiÚÙÈÛ‹ ÙÔ˘ ¤¯ÂÈ ·Ú·Ì¤ÓÔ˘Û· ·Ú·ÌfiÚʈ-ÛË 0,2%. ∆Ô ÌÂÁ¿ÏÔ Â‡ÚÔ˜ ÂÓÂÚÁÔÔ›ËÛ˘ ·Ú¤¯ÂÈ ÛÙÔÓÎÏÈÓÈÎfi ÙË ‰˘Ó·ÙfiÙËÙ· ÌÂÁ·Ï‡ÙÂÚˆÓ ÂÓÂÚÁÔÔÈ‹ÛˆÓÔ˘ Û˘Ó¿ÁÂÙ·È ÌÂÁ·Ï‡ÙÂÚÔ ¯ÚfiÓÔ ÏÂÈÙÔ˘ÚÁ›·˜ ÙÔ˘Û‡ÚÌ·ÙÔ˜ (Ingram Î·È Û˘Ó., 1986; Zufall Î·È Kusy,2000a).∏ ·Î·Ì„›· ‹ ‚·ıÌfi˜ ·Ú·ÌfiÚʈÛ˘ ηٿ ÙË ÊfiÚÙÈÛË(stiffness or load deflection rate) ÂÎÊÚ¿˙ÂÈ ÙÔ Ì¤ÁÂıÔ˜Ù˘ ‰‡Ó·Ì˘ Ô˘ ÌÔÚ› Ó· ·ÔÚÚÔÊ‹ÛÂÈ ¤Ó· ÛÒÌ· ηÈÂ›Ó·È ·Ó¿ÏÔÁÔ ÙÔ˘ ̤ÙÚÔ˘ ÂÏ·ÛÙÈÎfiÙËÙ·˜ (E) (GoldbergÎ·È Û˘Ó., 1983). ∏ ÌÈÎÚ‹ ·Î·Ì„›· ÙÔ˘ Û‡ÚÌ·ÙÔ˜ ·Ú¤¯ÂÈÙË ‰˘Ó·ÙfiÙËÙ· ÂÊ·ÚÌÔÁ‹˜ ‹ÈˆÓ ‰˘Ó¿ÌˆÓ, ·fi‰ÔÛ˘ÂÚÈÛÛfiÙÂÚÔ ÛÙ·ıÂÚ‹˜ ‰‡Ó·Ì˘ ηٿ ÙËÓ ·ÔÊfiÚÙÈÛËÎ·È ÌÂÁ·Ï‡ÙÂÚ˘ ·ÎÚ›‚ÂÈ·˜ ηٿ ÙËÓ ÚÔÛ¿ıÂÈ· ÂÊ·Ú-ÌÔÁ‹˜ ‰Â‰Ô̤Ó˘ ‰‡Ó·Ì˘ (Burstone Î·È Goldberg,1980).∏ ÈηÓfiÙËÙ· ‰È·ÌfiÚʈÛ˘ (formability) Â›Ó·È Ë Û˘ÁÎÂ-ÎÚÈ̤ÓË È‰ÈfiÙËÙ· Ô˘ ÂÈÙÚ¤ÂÈ ÙËÓ Â‡ÎÔÏË ‰È·ÌfiÚʈÛËÙÔ˘ Û‡ÚÌ·ÙÔ˜ ¯ˆÚ›˜ ıÚ·‡ÛË ‹ ÛËÌ·ÓÙÈ΋ ·ÏÏÔ›ˆÛË ÙˆÓ¯·Ú·ÎÙËÚÈÛÙÈÎÒÓ ÙÔ˘.∏ ·ÔıËÎÂ˘Ì¤ÓË ÂÓ¤ÚÁÂÈ· (stored energy or resilience)Â›Ó·È Ë È‰ÈfiÙËÙ· ÂÓfi˜ ˘ÏÈÎÔ‡ Ó· ·ÔıË·ÂÈ ÂÓ¤ÚÁÂȷηٿ ÙËÓ ÂÏ·ÛÙÈ΋ ·Ú·ÌfiÚʈÛË ÙÔ˘ Î·È Ó· ·Ô‰›‰ÂÈ·˘Ù‹ ÙËÓ ÂÓ¤ÚÁÂÈ· ηٿ ÙËÓ ·ÔÊfiÚÙÈÛË. ∆Ô ¯·Ú·ÎÙËÚÈ-ÛÙÈÎfi ·˘Ùfi ·ÓÙÈÚÔۈ‡ÂÈ ÙÔ ‰È·ı¤ÛÈÌÔ ¤ÚÁÔ ÁÈ· ÙËÓÔ‰ÔÓÙÈ΋ ÌÂٷΛÓËÛË.∏ ‚ÈÔÛ˘Ì‚·ÙfiÙËÙ· (biocompatibility, biohostability)ÂÚÈÏ·Ì‚¿ÓÂÈ ÙËÓ ·ÓÙ›ÛÙ·ÛË ÛÙË ‰È¿‚ÚˆÛË Î·È ÙËÓ ·ÓÂ-ÎÙÈÎfiÙËÙ· ÙˆÓ ÈÛÙÒÓ ÛÙ· ÛÙÔȯ›· ÙÔ˘ Û‡ÚÌ·ÙÔ˜. π‰·ÓÈο,ÙÔ Û‡ÚÌ· ‰ÂÓ ı· Ú¤ÂÈ Ó· ¢ÓÔ›, Ô‡Ù ӷ ·ÔÙÂÏ›˘fiÛÙڈ̷ ·Ó¿Ù˘Í˘ ÌÈÎÚÔÔÚÁ·ÓÈÛÌÒÓ Î·È Ó· ÚÔη-Ï› ·ÏÏÂÚÁ›Â˜.∏ ‰˘Ó·ÙfiÙËÙ· Û˘ÁÎfiÏÏËÛ˘ ÂÌ‚ÈÔÌ˯·ÓÈÎÒÓ ‚ÔËıËÌ¿-ÙˆÓ (welding or soldering) ÛÙ· Û‡ÚÌ·Ù· Â›Ó·È ÛËÌ·ÓÙÈÎ‹Î·È ÌÔÚ› Ó· Á›ÓÂÈ Ì ËÏÂÎÙÚÔÛ˘ÁÎfiÏÏËÛË ‹ Ì ÙË

agent. Low friction is a major property when attempting to rela-tively move a tooth/bracket along a wire.

TTYYPPEESS OOFF OORRTTHHOODDOONNTTIICC WWIIRREESS

SSttaaiinnlleessss SStteeeell ((SSSS))WWiirreess Stainless steel alloy used to produce orthodontic materialsis AISI (American Iron and Steel Institute) type 302 or 304(Khier et al., 1988). The stainless steel type commonlyused is also referred to as austenitic 18/8 suggesting itschromium and nickel content of approximately 18% and8%, respectively. This composition (mostly the chromiumcontent) allows the formation of a passivation oxide layerblocking oxygen diffusion to the underlying mass, thusmaking the alloy resistant to corrosion (i.e. biocompatibil-ity) and ensuring a steady austenitic crystal structure forsteel (Brantley 2001).Commercially available stainless steel wires have a rangeof values both for elasticity and yield strength related tothe change in different parameters at their productionstage such as freezing and incandescence during coldworking.The ratio of yield strength to the modulus of elasticity(YS/E) indicates a lower spring-back of stainless steel wiresthan those of beta-titanium or nickel-titanium. The storedenergy of activated stainless steel wires is also significant-ly lower than that of the other two types of wires(Andreasen and Morrow, 1978; Drake et al., 1982). Thisimplies that stainless steel wires produce higher forcesapplied during shorter time periods.Stainless steel wires may be soldered with different bio-mechanical attachments, mostly through a binding agent,although this process is highly demanding. New weldingtechniques recommended for use in orthodontics withouta binding agent but with the use of Laser or TIG (tungsteninert gas) welding produce satisfactory results, however,they are currently too expensive and require the use ofsophisticated laboratory equipment (Bock et al., 2008).As stated above, the corrosion resistance of stainless steelis good in general. A low release of nickel and chromiumis observed, which, however is below the dietary averageintake (House et al, 2008). Nickel, mostly, but chromium aswell, may induce hypersensitivity reactions. There is anapparently increasing interest in modern scientific litera-ture with regard to orthodontic patients, although long-term experience from the use of nickel-containing ortho-dontic appliances does not justify the rather strong con-troversy over their safety and biocompatibility (∂liadesand Athanasiou, 2002; Mikulewicz and Chojnacka, 2010).A recent meta-analysis concludes that orthodontic treat-ment is not related to an increased likelihood of hyper-sensitivity reactions to nickel unless there is a history ofskin piercing (Kolokitha et al., 2008).

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H 2011 ñ TOMO™ 14 ñ TEYXO™ 1 49

¯Ú‹ÛË Û˘ÁÎÔÏÏËÙÈÎÔ‡ ̤ÛÔ˘.∏ ¯·ÌËÏ‹ ÙÚÈ‚‹ (friction) ·ÔÙÂÏ› ÛËÌ·ÓÙÈ΋ ȉÈfiÙËÙ·fiÙ·Ó ÂȯÂÈÚÂ›Ù·È Ë Û¯ÂÙÈ΋ ÌÂٷΛÓËÛË ‰ÔÓÙÈÔ‡-·ÁÎ˘Ï›-Ô˘ ηٿ Ì‹ÎÔ˜ ÂÓfi˜ Û‡ÚÌ·ÙÔ˜.

∆∆ÀÀ¶¶√√ππ √√ƒƒ££√√¢¢√√¡¡∆∆ππ∫∫øø¡¡ ™™ÀÀƒƒªª∞∞∆∆øø¡¡

™™‡‡ÚÚÌÌ··ÙÙ·· ··fifi ··ÓÓÔÔÍÍ››‰‰ˆ̂ÙÙÔÔ ¯̄¿¿ÏÏ˘̆‚‚·· ‹‹ SSttaaiinnlleessss SStteeeell ((SSSS))∆Ô ÎÚ¿Ì· ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· Ô˘ ¯ÚËÛÈÌÔÔÈÂ›Ù·È ÁÈ·ÙËÓ Î·Ù·Û΢‹ ÔÚıÔ‰ÔÓÙÈÎÒÓ ˘ÏÈÎÒÓ Â›Ó·È AISI(American Iron and Steel Institute) Ù‡Ô˘ 302 ‹ 304(Khier Î·È Û˘Ó., 1988). √ Ù‡Ô˜ ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚·Ô˘ ¯ÚËÛÈÌÔÔÈÂ›Ù·È Û˘¯Ó¿ ·Ó·Ê¤ÚÂÙ·È Î·È ˆ˜ ˆÛÙÂÓÈÙÈ-Îfi˜ 18/8, ˘Ô‰ËÏÒÓÔÓÙ·˜ ÙËÓ ÂÚ›Ô˘ 18% Î·È 8%ÂÚÈÂÎÙÈÎfiÙËÙ· ÙÔ˘ Û ¯ÚÒÌÈÔ Î·È ÓÈΤÏÈÔ, ·ÓÙ›ÛÙÔȯ·. ∏Û‡ÛÙ·ÛË ·˘Ù‹ (΢ڛˆ˜ Ë ÂÚÈÂÎÙÈÎfiÙËÙ· Û ¯ÚÒÌÈÔ) ÂÈ-ÙÚ¤ÂÈ ÙË ‰ËÌÈÔ˘ÚÁ›· Ì›·˜ ÂÈÊ¿ÓÂÈ·˜ ÔÍÂȉ›ˆÓ ·ıËÙÈ-ÎÔÔ›ËÛ˘ (passivation oxide layer), Ë ÔÔ›· ÌÏÔοÚÂÈÙË ‰È¿¯˘ÛË Ô͢ÁfiÓÔ˘ ÛÙËÓ ˘ÔΛÌÂÓË Ì¿˙·, ÚÔÛ‰›‰Ô-ÓÙ·˜ ÛÙÔ ÎÚ¿Ì· ·ÓÙ›ÛÙ·ÛË ÛÙË ‰È¿‚ÚˆÛË (‰ËÏ·‰‹ ‚ÈÔ-Û˘Ì‚·ÙfiÙËÙ·) Î·È ÂÍ·ÛÊ·Ï›˙ÔÓÙ·˜ ÙË ÛÙ·ıÂÚ‹ ˆÛÙÂÓÈÙÈ-΋ ÎÚ˘ÛÙ·ÏÏÈ΋ ‰ÔÌ‹ ÙÔ˘ ¯¿Ï˘‚· (Brantley, 2001).∆· Û‡ÚÌ·Ù· ·fi ·ÓÔÍ›‰ˆÙÔ ¯¿Ï˘‚· Ô˘ Â›Ó·È ‰È·ı¤ÛÈ-Ì· ÛÙÔ ÂÌfiÚÈÔ ·ÚÔ˘ÛÈ¿˙Ô˘Ó ¤Ó· ‡ÚÔ˜ ÙÈÌÒÓ ÙfiÛÔ ÁÈ·ÙÔ Ì¤ÙÚÔ ÂÏ·ÛÙÈÎfiÙËÙ·˜ fiÛÔ Î·È ÁÈ· ÙÔ fiÚÈÔ ‰È·ÚÚÔ‹˜Ô˘ Û¯ÂÙ›˙ÔÓÙ·È Ì ÙË ÌÂÙ·‚ÔÏ‹ ‰È¿ÊÔÚˆÓ ·Ú·Ì¤ÙÚˆÓηٿ ÙËÓ Î·Ù·Û΢‹ ÙÔ˘˜, fiˆ˜ ÙÔ˘ ‚·ıÌÔ‡ „‡Í˘ ‹˘Ú¿ÎÙˆÛ˘ ηٿ ÙÔ˘˜ ·ÎÏÔ˘˜ „˘¯Ú‹˜ ηÙÂÚÁ·Û›·˜(cold working).∏ ·Ó·ÏÔÁ›· ÙÔ˘ ÔÚ›Ô˘ ‰È·ÚÚÔ‹˜ ÚÔ˜ ÙÔ Ì¤ÙÚÔ ÂÏ·ÛÙÈ-ÎfiÙËÙ·˜ (YS/E) ˘Ô‰ËÏÒÓÂÈ ÌÈÎÚfiÙÂÚÔ Â‡ÚÔ˜ ÂÓÂÚÁÔÔ›-ËÛ˘ ÁÈ· Ù· Û‡ÚÌ·Ù· ·fi ·ÓÔÍ›‰ˆÙÔ ¯¿Ï˘‚· Û ۯ¤ÛËÌ ‚-ÙÈÙ·Ó›Ô˘ ‹ ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘. ∏ ·ÔıËÎÂ˘Ì¤ÓË ÂÓ¤Ú-ÁÂÈ· ÙˆÓ ÂÓÂÚÁÔÔÈËÌ¤ÓˆÓ Û˘ÚÌ¿ÙˆÓ ·fi ·ÓÔÍ›‰ˆÙÔ¯¿Ï˘‚· ›Û˘ Â›Ó·È ÛËÌ·ÓÙÈο ÌÈÎÚfiÙÂÚË ·fi ÙÔ˘˜¿ÏÏÔ˘˜ ‰‡Ô Ù‡Ô˘˜ Û˘ÚÌ¿ÙˆÓ (Andreasen Î·È Morrow,1978; Drake Î·È Û˘Ó., 1982). ∞˘Ùfi ÛËÌ·›ÓÂÈ ˆ˜ Ù· Û‡Ú-Ì·Ù· ·fi ·ÓÔÍ›‰ˆÙÔ ¯¿Ï˘‚· ·Ú¿ÁÔ˘Ó ÂÓÙÔÓfiÙÂÚ˜‰˘Ó¿ÌÂȘ Ô˘ ·ÛÎÔ‡ÓÙ·È Û ÌÈÎÚfiÙÂÚ˜ ¯ÚÔÓÈΤ˜ ÂÚÈfi-‰Ô˘˜.™Ù· Û‡ÚÌ·Ù· ·fi ·ÓÔÍ›‰ˆÙÔ ¯¿Ï˘‚· ÌÔÚÔ‡Ó Ó·Á›ÓÔ˘Ó ÚÔÛ·ÚÙ‹ÛÂȘ ‰È·ÊfiÚˆÓ ÂÌ‚ÈÔÌ˯·ÓÈÎÒÓ ‚ÔË-ıËÌ¿ÙˆÓ, ΢ڛˆ˜ Ì ÙË ‚Ô‹ıÂÈ· Û˘ÁÎÔÏÏËÙÈÎÔ‡ ̤ÛÔ˘,·Ó Î·È ·˘Ùfi ÔÚÈṲ̂Ó˜ ÊÔÚ¤˜ Â›Ó·È ÌÈ· ·ÚÎÂÙ¿ ··ÈÙËÙÈ΋‰È·‰Èηۛ·. ¡¤Â˜ Ù¯ÓÈΤ˜ Û˘ÁÎfiÏÏËÛ˘ Ô˘ ÚÔÙ›ÓÔ-ÓÙ·È ÁÈ· ¯Ú‹ÛË ÛÙËÓ ÔÚıÔ‰ÔÓÙÈ΋, ¯ˆÚ›˜ ÙËÓ ¯Ú‹ÛËÛ˘ÁÎÔÏÏËÙÈÎÔ‡ ̤ÛÔ˘ Ì ¯Ú‹ÛË Ù¯ÓÔÏÔÁ›·˜ Laser ›ÙÂTIG (·‰Ú·Ó¤˜ ·¤ÚÈÔ ‚ÔÏÊÚ·Ì›Ô˘), ‰›ÓÔ˘Ó Î·Ï¿ ·ÔÙÂϤ-ÛÌ·Ù·, ˆÛÙfiÛÔ ÚÔ˜ ÙÔ ·ÚfiÓ Â›Ó·È Ôχ ‰··ÓËÚ¤˜ ηÈÚÔ¸Ôı¤ÙÔ˘Ó ¯Ú‹ÛË ÂÍÂȉÈÎÂ˘Ì¤ÓÔ˘ ÂÚÁ·ÛÙËÚÈ·ÎÔ‡

It has been found that stainless steel wires have a lowerbracket-wire friction than other types of wires (Kusy andWhitley, 1990; Kapila et al., 1990; Krishnan and Kumar,2004a), whereas experiments have achieved to furtherreduce friction values using nanotechnology applications(Redlich et al., 2008)Australian Wires are a particular type of stainless steelwires available in different grades representing graduallyincreasing stored energy values (resiliency). These wiresare considered to be made of standard 18/8 stainless steel,however a recent study (Pelsue et al., 2009) reports carboncontent up to 10 times higher than that in a standardstainless steel orthodontic wire (up to 0.20%). This mayexplain increased surface roughness, hardness, porosity,and propensity for breakage during clinical bending, par-ticularly for higher grades (Pelsue et al., 2009). This is whyhigher grades, despite their high stored energy, are cur-rently used solely as biomechanical attachments. Recently, super stainless steels have been developed,which have a lower nickel content, higher corrosion resis-tance, and improved mechanical properties. These desiredcharacteristics may widen the use of stainless steel wiresin the future since they are expected to supersede titani-um wires in terms of high cost and low configuration abil-ity (Oh et al., 2003).

CCoobbaalltt--cchhrroommiiuumm wwiirreess Cobalt-chromium wires are commercially available ingrades based on their ability to store energy for a givenforce. These wires have very good formability prior to heattreatment, which takes place once they are configured,thus increasing their stored energy and functionality(Kusy, 1997). With only a few exceptions, non-heat treat-ed cobalt-chromium wires have a smaller spring-back thanstainless steel wires of the same section (Ingram et al.,1986). However, once subjected to heat treatment in adental oven (482 ÆC for 7-12 minutes), this property isimproved (Ingram et al., 1986). Heating causes the accel-erated hardening of the alloy, increasing its resistance todeformation (Filmore and Tomlinson, 1979), and as aresult, the wire has mechanical properties similar to thoseof stainless steel. High formability combined withincreased elasticity and yield strength following heattreatment by 10% and 20-30%, respectively, has madeBlue Elgiloy, a cobalt-chromium wire type, popular in clin-ical practice. Other properties of these wires show significant similari-ties to those of stainless steel wire properties (Meling andOdegaard, 1998a; Kusy et al., 2001). Therefore, in mostcases, these wires may be replaced by stainless steel wiresof the same section, but of lower cost, which explainstheir declining use in orthodontic clinical practice (Kusyand Greenberg, 1981; Kusy et al., 2001). Moreover, withregard to torque control, Meling and Odegaard (1998b)

π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires HELLENIC ORTHODONTIC REVIEW

50 HELLENIC ORTHODONTIC REVIEW 2011 ñ VOLUME 14 ñ ISSUE 1

ÂÍÔÏÈÛÌÔ‡ (Bock Î·È Û˘Ó., 2008).Ÿˆ˜ ÚԷӷʤÚıËÎÂ, Ë ·ÓÙ›ÛÙ·ÛË ÙÔ˘ ·ÓÔÍ›‰ˆÙÔ˘¯¿Ï˘‚· ÛÙË ‰È¿‚ÚˆÛË Â›Ó·È ÁÂÓÈο ηϋ. ¶·Ú·ÙËÚ›ٷÈÌÈÎÚÔ‡ ‚·ıÌÔ‡ ·ÂÏ¢ı¤ÚˆÛË ÓÈÎÂÏ›Ô˘ Î·È ¯ÚˆÌ›Ô˘, ËÔÔ›· fï˜ Â›Ó·È Î·ÙÒÙÂÚË ÙÔ˘ ̤ÛÔ˘ fiÚÔ˘ ÚfiÛÏ˄˘·fi ÙË ‰›·ÈÙ· (House Î·È Û˘Ó., 2008). ∆Ô ÓÈΤÏÈÔ Î˘Ú›ˆ˜,·ÏÏ¿ Î·È ÙÔ ¯ÚÒÌÈÔ, ‰‡Ó·ÓÙ·È Ó· ÚÔηϤÛÔ˘Ó ·ÓÙȉڿ-ÛÂȘ ˘ÂÚ¢·ÈÛıËÛ›·˜. ∆Ô ÂӉȷʤÚÔÓ Ù˘ ÂÈÛÙËÌÔÓÈ΋˜ÎÔÈÓfiÙËÙ·˜ fiÛÔÓ ·ÊÔÚ¿ ÙÔ˘˜ ÔÚıÔ‰ÔÓÙÈÎÔ‡˜ ·ÛıÂÓ›˜Â›Ó·È ÂÌÊ·ÓÒ˜ ·˘Í·ÓfiÌÂÓÔ ÛÙË Û‡Á¯ÚÔÓË ‚È‚ÏÈÔÁÚ·Ê›·,·Ó Î·È Ë Ì·ÎÚÔ¯ÚfiÓÈ· ÂÌÂÈÚ›· ·fi ÙË ¯Ú‹ÛË ÔÚıÔ‰Ô-ÓÙÈÎÒÓ Û˘Û΢ÒÓ Ô˘ ÂÚȤ¯Ô˘Ó ÓÈΤÏÈÔ ‰ÂÓ ‰ÈηÈÔÏÔ-Á› ÙÔ Û¯ÂÙÈο ¤ÓÙÔÓÔ ÚÔ‚ÏËÌ·ÙÈÛÌfi ÂÚ› Ù˘ ·ÛÊ¿ÏÂÈ-·˜ Î·È ‚ÈÔÛ˘Ì‚·ÙfiÙËÙ¿˜ ÙÔ˘˜ (∂liades Î·È Athanasiou,2002; Mikulewicz Î·È Chojnacka, 2010). ¶ÚfiÛÊ·ÙËÌÂÙ¿-·Ó¿Ï˘ÛË Î·Ù·Ï‹ÁÂÈ ÛÙÔ fiÙÈ Ë ÔÚıÔ‰ÔÓÙÈ΋ ıÂÚ·-›· ‰ÂÓ Û˘Ó‰¤ÂÙ·È Ì ·˘ÍË̤ÓË Èı·ÓfiÙËÙ· ·Ó¿Ù˘Í˘˘ÂÚ¢·ÈÛıËÛ›·˜ ÛÙÔ ÓÈΤÏÈÔ ÂÎÙfi˜ ·Ó ˘¿Ú¯ÂÈ ÈÛÙÔÚÈÎfi‰ÂÚÌ·ÙÈÎÔ‡ piercing (Kolokitha Î·È Û˘Ó., 2008).Œ¯ÂÈ ‚ÚÂı› ˆ˜ Ù· Û‡ÚÌ·Ù· ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· ¤¯Ô˘ÓÌÈÎÚfiÙÂÚË ÙÚÈ‚‹ Û‡ÚÌ·ÙÔ˜-·ÁÎ˘Ï›Ô˘ ·fi fiÙÈ ÔÈ ¿ÏÏÔÈÙ‡ÔÈ Û˘ÚÌ¿ÙˆÓ (Kusy Î·È Whitley, 1990; Kapila ηÈÛ˘Ó., 1990; Krishnan Î·È Kumar, 2004a), ÂÓÒ Û ÂÈÚ·-Ì·ÙÈÎfi Â›Â‰Ô ÂÈÙ˘Á¯¿ÓÂÙ·È ÂÚ·ÈÙ¤Úˆ ‚ÂÏÙ›ˆÛË ÙˆÓÙÈÌÒÓ ÙÚÈ‚‹˜ Ì ¯Ú‹ÛË ÂÊ·ÚÌÔÁÒÓ Ó·ÓÔÙ¯ÓÔÏÔÁ›·˜(Redlich Î·È Û˘Ó., 2008)∆· Û‡ÚÌ·Ù· Ù‡Ô˘ Australian Wires ·ÔÙÂÏÔ‡Ó ¤Ó·ÓÂȉÈÎfi Ù‡Ô Û˘ÚÌ¿ÙˆÓ ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· Ô˘ ‰È·Ù›-ıÂÓÙ·È Û ‰È·‚·ıÌ›ÛÂȘ Ô˘ ·ÓÙÈÚÔÛˆÂ‡Ô˘Ó ÚÔԉ¢-ÙÈο ·˘Í·ÓfiÌÂÓ˜ ÙÈ̤˜ ÈηÓfiÙËÙ·˜ ·Ôı‹Î¢Û˘ ÂÓ¤Ú-ÁÂÈ·˜ (resiliency). ∆· Û‡ÚÌ·Ù· ·˘Ù¿ ıˆÚÂ›Ù·È fiÙÈ Î·Ù·-Û΢¿˙ÔÓÙ·È ·fi ÙÔÓ ÎÏ·ÛÈÎfi Ù‡Ô 18/8 ·ÓÔÍ›‰ˆÙÔ˘¯¿Ï˘‚·, ˆÛÙfiÛÔ ÚfiÛÊ·ÙË ÌÂϤÙË (Pelsue Î·È Û˘Ó.,2009) ·Ó·Ê¤ÚÂÈ ÙËÓ ¤ˆ˜ Î·È 10 ÊÔÚ¤˜ ÌÂÁ·Ï‡ÙÂÚË ÂÚÈÂ-ÎÙÈÎfiÙËÙ· Û ¿Óıڷη Û ۯ¤ÛË Ì ·˘Ù‹ ÙÔ˘ Ù˘ÈÎÔ‡ÔÚıÔ‰ÔÓÙÈÎÔ‡ Û‡ÚÌ·ÙÔ˜ ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· (¤ˆ˜0,20%). ∞˘Ùfi ÌÔÚ› Ó· ÂÍËÁ‹ÛÂÈ Î·È ÙËÓ ·˘ÍË̤ÓË ÂÈ-Ê·ÓÂȷ΋ ÙÚ·¯‡ÙËÙ·, ÛÎÏËÚfiÙËÙ·, ÔÚ҉˜ Î·È Ù¿ÛË ÁÈ·ıÚ·‡ÛË Î·Ù¿ ÙËÓ ÂÊ·ÚÌÔÁ‹ ÎÏÈÓÈÎÒÓ Î¿Ì„ÂˆÓ È‰È·›ÙÂÚ·ÛÙȘ ·ÓÒÙÂÚ˜ ‰È·‚·ıÌ›ÛÂȘ ÙÔ˘˜ (Pelsue Î·È Û˘Ó., 2009).°È' ·˘Ùfi ÔÈ ·ÓÒÙÂÚ˜ ‰È·‚·ıÌ›ÛÂȘ, ·Ú¿ ÙËÓ ˘„ËÏ‹ Èη-ÓfiÙËÙ· ·Ôı‹Î¢Û˘ ÂÓ¤ÚÁÂÈ·˜, ¯ÚËÛÈÌÔÔÈÔ‡ÓÙ·È Û‹ÌÂ-Ú· ÌfiÓÔ ˆ˜ ÂÌ‚ÈÔÌ˯·ÓÈο ‚ÔËı‹Ì·Ù·.¶ÚfiÛÊ·Ù·, ¤¯Ô˘Ó ·Ó·Ù˘¯ı› ÎÚ¿Ì·Ù· ·ÓÔÍ›‰ˆÙÔ˘¯¿Ï˘‚· (super stainless steels) Ì ÌÈÎÚfiÙÂÚË ÂÚÈÂÎÙÈÎfi-ÙËÙ· Û ÓÈΤÏÈÔ, ÌÂÁ·Ï‡ÙÂÚË ·ÓÙ›ÛÙ·ÛË ÛÙË ‰È¿‚ÚˆÛËÎ·È ‚ÂÏÙȈ̤Ó˜ Ì˯·ÓÈΤ˜ ȉÈfiÙËÙ˜. ∆· ÂÈı˘ÌËÙ¿ ·˘Ù¿¯·Ú·ÎÙËÚÈÛÙÈο ÌÔÚ› ÛÙÔ Ì¤ÏÏÔÓ Ó· ‰È¢ڇÓÔ˘Ó Ù˯ڋÛË ÙˆÓ Û˘ÚÌ¿ÙˆÓ ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚·, ηıÒ˜ ·Ó·-̤ÓÂÙ·È ˆ˜ ı· ˘ÂÚÙÂÚÔ‡Ó ÙˆÓ Û˘ÚÌ¿ÙˆÓ ·fi ÎÚ¿Ì·Ù·

report that it is difficult to achieve with cobalt-chromiumwires since softer wires have a greater variability in theirdimensions depending on the manufacturer, and harderones have a high stiffness making the precise applicationof torque to a specific part of the wire arch a highlydemanding process. Furthermore, caution is requiredwhile welding biomechanic attachments since high tem-perature causes hardening and subsequent reduction inthe yield and tensile strengths (Filmore and Tomlinson,1976). Therefore, it is recommended to use a low-fusionbinding agent (Kapila and Sachdeva, 1989).

BBeettaa--ttiittaanniiuumm wwiirreessThe use of beta-titanium alloys as orthodontic wires hasbeen introduced in 1979 (Goldberg and Burstone, 1979;Burstone and Goldberg, 1980). These wires are alsoknown as titanium-molybdenium alloy (∆ª∞) (ORMCO,Orange, CA, USA) or Titanium Niobium (ORMCO, Orange,CA, USA), since they were the first ones to be manufac-tured and the only ones commercially available for sever-al years.These wires have a modulus of elasticity lower than halfof stainless steel wires and almost twice that of Nitinol(Verstrynge et al., 2006; Juvvadi et al., 2010). A beta-tita-nium wire can be deflected almost twice as much as a sim-ilar stainless steel wire (Goldberg and Burstone, 1979; Bur-stone and Goldberg, 1980). Moreover, it delivers half theamount of force applied compared to a stainless steel wireof similar section (Goldberg and Burstone, 1979; Burstoneand Goldberg, 1980).These wires demonstrate good formability, but should notbe strongly bent for there is a risk of breaking (Burstoneand Goldberg, 1980). Electrical welding of biomechanicalattachments is possible, but it should be made within aspecific voltage range (Nelson et al., 1987) using wideelectrodes (Donovan et al., 1984), so that wire propertiesare not altered since overheating makes it brittle (Bur-stone and Goldberg, 1980; Nelson et al., 1987). Accordingto a recent study, beta-titanium wires are better in termsof joinability than stainless steel wires since they demon-strate higher resilience and better surface and structuralcharacteristics, which indicates only a minor change inwire properties after welding (Krishnan Î·È Kumar, 2004b).Controversy over biocompatibility for beta-titanium wiresis reduced due to the absence of nickel, although theirresistance to corrosion is similar to that of cobalt-chromi-um and stainless steel wires. Their resistance to corrosionis due to the formation of a surface passivation oxide layer(Kim and Johnson, 1999), whereas it should be noted thatexposure to fluoride agents often used by orthodonticpatients leads to the degradation, subsequent corrosion,and qualitative alteration of the wire’s surface (Walker etal., 2007). Experimental studies have shown that this neg-atively affects the mechanical properties of deactivation of

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H 2011 ñ TOMO™ 14 ñ TEYXO™ 1 51

ÙÈÙ·Ó›Ô˘ ˆ˜ ÚÔ˜ ÙÔ ˘„ËÏfi ÎfiÛÙÔ˜ Î·È ÙË ÌÈÎÚ‹ ÈηÓfiÙË-Ù· ‰È·ÌfiÚʈÛ˘ ÙÔ˘˜ (Oh Î·È Û˘Ó., 2003).

™™‡‡ÚÚÌÌ··ÙÙ·· ÎÎÔÔ‚‚··ÏÏÙÙ››ÔÔ˘̆--¯̄ÚÚˆ̂ÌÌ››ÔÔ˘̆ ™ÙÔ ÂÌfiÚÈÔ Â›Ó·È ‰È·ı¤ÛÈÌ· ‰È¿ÊÔÚ· ÎÚ¿Ì·Ù· ÎÔ‚·ÏÙ›-Ô˘-¯ÚˆÌ›Ô˘ Ì ‰È·‚·ıÌ›ÛÂȘ Û¯ÂÙÈο Ì ÙËÓ ÈηÓfiÙËÙ··Ôı‹Î¢Û˘ ÂÓ¤ÚÁÂÈ·˜ ÁÈ· ‰Â‰Ô̤ÓË ‰‡Ó·ÌË. ∆· Û‡Ú-Ì·Ù· ·˘Ù¿ ¤¯Ô˘Ó Ôχ ηϋ ÈηÓfiÙËÙ· ‰È·ÌfiÚʈÛ˘ÚÈÓ ÙË ıÂÚÌÈ΋ ηÙÂÚÁ·Û›·, Ë ÔÔ›· Ï·Ì‚¿ÓÂÈ ¯ÒÚ·ÌÂÙ¿ ÙË ‰È·ÌfiÚʈÛË ÙÔ˘˜, ·˘Í¿ÓÔÓÙ·˜ ÙËÓ ·ÔıËÎÂ˘Ì¤-ÓË ÂÓ¤ÚÁÂÈ· Î·È ÙË ÏÂÈÙÔ˘ÚÁÈÎfiÙËÙ· ÙÔ˘˜ (Kusy, 1997).ªÂ ÂÏ¿¯ÈÛÙ˜ ÂÍ·ÈÚ¤ÛÂȘ, Ù· Û‡ÚÌ·Ù· ÎÔ‚·ÏÙ›Ô˘ ¯ÚˆÌ›-Ô˘ ÚÈÓ ˘ÔÛÙÔ‡Ó ıÂÚÌÈ΋ ηÙÂÚÁ·Û›· ¤¯Ô˘Ó ÌÈÎÚfiÙÂÚË̤ÁÈÛÙË ÂÏ·ÛÙÈ΋ ·Ú·ÌfiÚʈÛË ·fi Û‡ÚÌ·Ù· ·ÓÔÍ›-‰ˆÙÔ˘ ¯¿Ï˘‚· ›‰È·˜ ‰È·ÙÔÌ‹˜ (Ingram Î·È Û˘Ó., 1986).øÛÙfiÛÔ, ÌÂÙ¿ ·fi ηٿÏÏËÏË ıÂÚÌÈ΋ ηÙÂÚÁ·Û›· ÛÂÔ‰ÔÓÙÈ·ÙÚÈÎfi ÎÏ›‚·ÓÔ (482 ÆC ÁÈ· 7-12 ÏÂÙ¿) Ë ·Ú·-¿Óˆ ȉÈfiÙËÙ· ‚ÂÏÙÈÒÓÂÙ·È (Ingram Î·È Û˘Ó., 1986). ∏ı¤ÚÌ·ÓÛË ÚÔηÏ› ÂÈÙ·¯˘ÓfiÌÂÓË ÛÎÏ‹Ú˘ÓÛË ÙÔ˘ ÎÚ¿-Ì·ÙÔ˜, ·˘Í¿ÓÔÓÙ·˜ ÙËÓ ·ÓÙ›ÛÙ·ÛË ÙÔ˘ ÛÙËÓ ·Ú·ÌfiÚʈ-ÛË (Filmore Î·È Tomlinson, 1979) Ì ·ÔÙ¤ÏÂÛÌ· ÙÔÛ‡ÚÌ· Ó· ÂÌÊ·Ó›˙ÂÈ ·ÚfiÌÔȘ Ì˯·ÓÈΤ˜ ȉÈfiÙËÙ˜ Ì·˘Ù¤˜ ÙÔ˘ ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚·. ∏ ˘„ËÏ‹ ÈηÓfiÙËÙ· ‰È·-ÌfiÚʈÛ˘, ÛÂ Û˘Ó‰˘·ÛÌfi Ì ÙËÓ ·‡ÍËÛË ÙÔ˘ ̤ÙÚÔ˘ÂÏ·ÛÙÈÎfiÙËÙ·˜ Î·È ÔÚ›Ô˘ ‰È·ÚÚÔ‹˜ ÌÂÙ¿ ·fi ıÂÚÌÈ΋ηÙÂÚÁ·Û›· ηٿ 10% Î·È 20-30% ·ÓÙ›ÛÙÔȯ·, ¤¯ÂÈ Î¿ÓÂÈÛ˘ÁÎÂÎÚÈ̤ӷ ÙÔÓ Ù‡Ô Û‡ÚÌ·ÙÔ˜ ÎÔ‚·ÏÙ›Ô˘-¯ÚˆÌ›Ô˘µlue Elgiloy ‰ËÌÔÊÈÏ‹ ηٿ ÙËÓ ÎÏÈÓÈ΋ ¯Ú‹ÛË.√È ¿ÏϘ ȉÈfiÙËÙ˜ ÙˆÓ Û˘ÚÌ¿ÙˆÓ ·˘ÙÒÓ ÂÌÊ·Ó›˙Ô˘ÓÛËÌ·ÓÙÈΤ˜ ÔÌÔÈfiÙËÙ˜ Ì ÙȘ ȉÈfiÙËÙ˜ ÙˆÓ Û˘ÚÌ¿ÙˆÓ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· (Meling Î·È Odegaard, 1998a;Kusy Î·È Û˘Ó., 2001). ŒÙÛÈ, ÛÙȘ ÂÚÈÛÛfiÙÂÚ˜ ÂÚÈÙÒ-ÛÂȘ Ù· Û‡ÚÌ·Ù· ·˘Ù¿ ÌÔÚÔ‡Ó Ó· ·ÓÙÈηٷÛÙ·ıÔ‡Ó ·fiÛ‡ÚÌ·Ù· ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· ›‰È·˜ ‰È·ÙÔÌ‹˜ ·ÏÏ¿¯·ÌËÏfiÙÂÚÔ˘ ÎfiÛÙÔ˘˜, ÁÂÁÔÓfi˜ Ô˘ ÂÍËÁ› ÙË ÌÂȈ̤Ó˯ڋÛË ÙÔ˘˜ ÛÙËÓ ÔÚıÔ‰ÔÓÙÈ΋ ÎÏÈÓÈ΋ Ú¿ÍË (Kusy ηÈGreenberg, 1981; Kusy Î·È Û˘Ó., 2001). ∞ÎfiÌË, Û¯ÂÙÈοÌ ÙÔÓ ¤ÏÂÁ¯Ô Ù˘ ÛÙÚ¤„˘ (torque), ÔÈ Meling ηÈOdegaard (1998b) ·Ó·Ê¤ÚÔ˘Ó ˆ˜ ÂÈÙ˘Á¯¿ÓÂٷȉ‡ÛÎÔÏ· Ì ۇÚÌ·Ù· ÎÔ‚·ÏÙ›Ô˘-¯ÚˆÌ›Ô˘ ÁÈ·Ù› Ù· ËÈfi-ÙÂÚ· Û‡ÚÌ·Ù· ÂÌÊ·Ó›˙Ô˘Ó, ·Ó¿ÏÔÁ· Ì ÙÔÓ Î·Ù·Û΢·-ÛÙ‹, ÌÂÁ¿Ï˜ ‰È·Î˘Ì¿ÓÛÂȘ ÛÙȘ ‰È·ÛÙ¿ÛÂȘ ÙÔ˘˜, Î·È Ù·‚·Ú‡ÙÂÚ· ¤¯Ô˘Ó ˘„ËÏ‹ ÛÙÚÂÙÈ΋ ·Î·Ì„›·, ηıÈÛÙÒÓÙ·˜ÙËÓ ·ÎÚÈ‚‹ ÙÔÔı¤ÙËÛË Ù˘ ÛÙÚ¤„˘ (torque) ÛÂ Û˘ÁÎÂ-ÎÚÈ̤ÓÔ ÙÌ‹Ì· ÙÔ˘ Û˘ÚÌ¿ÙÈÓÔ˘ ÙfiÍÔ˘ ÌÈ· ȉȷ›ÙÂÚ· ··È-ÙËÙÈ΋ Ú¿ÍË. ∞ÎfiÌË, ··ÈÙÂ›Ù·È ÚÔÛÔ¯‹ ηٿ ÙËÛ˘ÁÎfiÏÏËÛË ÂÌ‚ÈÔÌ˯·ÓÈÎÒÓ ‚ÔËıËÌ¿ÙˆÓ, ηıÒ˜ ˢ„ËÏ‹ ıÂÚÌÔÎÚ·Û›· ÚÔηÏ› ÛÎÏ‹Ú˘ÓÛË Ì ·Îfi-ÏÔ˘ıË Ì›ˆÛË ÙÔ˘ ÔÚ›Ô˘ ‰È·ÚÚÔ‹˜ Î·È Ù˘ ·ÓÙÔ¯‹˜ ÛÂÂÊÂÏ΢ÛÌfi (Filmore Î·È Tomlinson, 1976). °È’ ·˘Ùfi,

these wires, as well as of those made of stainless steel andNiTi (Kwon et al., 2005; Walker et al., 2005; Walker et al.,2007). Meanwhile, their ion release is increased giving riseto biocompatibility concerns. The duration of wire expo-sure to fluoride agents appears to play a major role(Ogawa et al., 2004). However, most data about the effectof fluoride agents on titanium materials comes from invitro studies with oversimplified assumptions of the simu-lation of oral cavity conditions. These findings should beconfirmed by in vivo studies (Fragou and Eliades, 2010).Their high cost, as well as their bracket-wire friction,which is higher than any other alloy, is considered a dis-advantage (Kusy and Whitley, 1989; Kapila et al., 1990;Cash et al., 2004; Krishnan and Kumar, 2004a), althoughthe development of beta-titanium wires appears toimprove the quality of surface finish, and subsequently,friction values (Kusy et al., 2004). A new wire made of an alpha-beta titanium alloy calledTiMolium (TP Labs) has been recently launched. Accordingto the study by Krishnan and Kumar (2004a), this wire’sstiffness and other characteristics (such as elasticity andyield strength) are between the values set for stainlesssteel and beta-titanium wires.

NNiicckkeell--ttiittaanniiuumm oorr NNii--TTii wwiirreessThe first nickel-titanium wire (Nitinol) was introduced foruse in orthodontics by Andreasen and Hileman in 1971.The first generation of NiTi alloys demonstrated the"shape memory" effect, which refers to the wire’s proper-ty to return to a previously manufactured shape afterdeflection when heated. This return occurs within a tran-sitional temperature range (TTR) (Andreasen et al., 1985).This effect has been described by Andreasen et al. (1985)as "superelasticity". Superelasticity is the effect duringwhich the wire applies a low, constant force with a"plateau" during its loading or unloading (πijima et al.,2002). This definition was based on structural changesoccurring in the wire (phase transformation) duringchanges in temperature or its loading process (Meling andOdegaard, 2001).In 1985, Burstone et al recommended the Chinese NiTi(Ormco, Orange, CA, USA), which exhibited 4.4 times thespring-back of stainless steel wires and 1.6 times thespring-back of the original Nitinol and provided a constantforce in the middle of its deactivation range (Bradley et al.,1996). One year later, Miura et al. (1986) introduced theJapanese NiTi (Sentalloy, DENTSPLY GAC International,Bohemia, NY) with similar properties (Brantley et al.,1997). Finally, in the early ‘90s, GAC introduced a newwire (NeoSentalloy) having a pure shape memory in oralcavity temperature, whereas Ormco introduced CuNiTi atthat time (Gioka and Eliades, 2002).With regard to the metallurgical structure of NiTi alloys,there are two major phases and an intermediate one. The

π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires HELLENIC ORTHODONTIC REVIEW

52 HELLENIC ORTHODONTIC REVIEW 2011 ñ VOLUME 14 ñ ISSUE 1

Û˘Ó›ÛÙ·Ù·È Ë ¯Ú‹ÛË Û˘ÁÎÔÏÏËÙÈÎÔ‡ ̤ÛÔ˘ Ì ¯·ÌËÏfiÛËÌÂ›Ô Ù‹Í˘ (Kapila Î·È Sachdeva, 1989).

™™‡‡ÚÚÌÌ··ÙÙ·· ‚‚--ÙÙÈÈÙÙ··ÓÓ››ÔÔ˘̆∏ ¯Ú‹ÛË ÙˆÓ ÎÚ·Ì¿ÙˆÓ ‚-ÙÈÙ·Ó›Ô˘ ˆ˜ ÔÚıÔ‰ÔÓÙÈο Û‡Ú-Ì·Ù· ÚÔÙ¿ıËΠÙÔ 1979 (Goldberg Î·È Burstone, 1979;Burstone Î·È Goldberg, 1980). ∆· Û‡ÚÌ·Ù· ·˘Ù¿ ›ӷÈ›Û˘ ÁÓˆÛÙ¿ Î·È ˆ˜ titanium-molybdenium alloy(∆ª∞) (ORMCO, Orange, CA, USA) ‹ Titanium Niobium(ORMCO, Orange, CA, USA), ηıÒ˜ Â›Ó·È Ù· ÚÒÙ· Ô˘Î·Ù·Û΢¿ÛÙËÎ·Ó Î·È ‹Ù·Ó ÌÔÓ·‰Èο ÛÙÔ ÂÌfiÚÈÔ ÁÈ··ÚÎÂÙ¿ ¯ÚfiÓÈ·.∆· Û‡ÚÌ·Ù· ·˘Ù¿ ¤¯Ô˘Ó ̤ÙÚÔ ÂÏ·ÛÙÈÎfiÙËÙ·˜ ÌÈÎÚfiÙÂÚÔ·fi ÙÔ ÌÈÛfi ÙˆÓ Û˘ÚÌ¿ÙˆÓ ·fi ·ÓÔÍ›‰ˆÙÔ ¯¿Ï˘‚· ηÈۯ‰fiÓ ‰ÈÏ¿ÛÈÔ ·fi Ùo Nitinol (Verstrynge Î·È Û˘Ó.,2006; Juvvadi Î·È Û˘Ó., 2010). ŒÓ· Û‡ÚÌ· ‚-ÙÈÙ·Ó›Ô˘ÌÔÚ› Ó· ·Ú·ÌÔÚʈı› ÂÏ·ÛÙÈο ۯ‰fiÓ ‰ÈÏ¿ÛÈ··fi ¤Ó· ·ÓÙ›ÛÙÔÈ¯Ô ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· (Goldberg ηÈBurstone, 1979; Burstone Î·È Goldberg, 1980). ∂›Û˘,·Ô‰›‰ÂÈ ÙÔ ÌÈÛfi ̤ÁÂıÔ˜ ·ÛÎÔ‡ÌÂÓ˘ ‰‡Ó·Ì˘ Û ۯ¤ÛËÌ ¤Ó· ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· ·ÓÙ›ÛÙÔȯ˘ ‰È·ÙÔÌ‹˜(Goldberg Î·È Burstone, 1979; Burstone Î·È Goldberg,1980).∆· Û˘ÁÎÂÎÚÈ̤ӷ Û‡ÚÌ·Ù· ¤¯Ô˘Ó ȉȷ›ÙÂÚ· ηϋ ÈηÓfi-ÙËÙ· ‰È·ÌfiÚʈÛ˘, ·ÏÏ¿ ‰ÂÓ ı· Ú¤ÂÈ Ó· οÌÙÔÓٷȤÓÙÔÓ· ÁÈ·Ù› ˘¿Ú¯ÂÈ Î›Ó‰˘ÓÔ˜ ıÚ·‡Û˘ (Burstone ηÈGoldberg, 1980). ∏ ËÏÂÎÙÚÔÛ˘ÁÎfiÏÏËÛË ÂÌ‚ÈÔÌ˯·ÓÈ-ÎÒÓ ‚ÔËıËÌ¿ÙˆÓ Â›Ó·È ‰˘Ó·Ù‹, ·ÏÏ¿ ı· Ú¤ÂÈ Ó· Á›ÓÂ-Ù·È ÛÂ Û˘ÁÎÂÎÚÈ̤ÓÔ Â‡ÚÔ˜ Ù¿Û˘ (Nelson Î·È Û˘Ó., 1987)Î·È Ì ϷÙÈ¿ ËÏÂÎÙÚfi‰È· (Donovan Î·È Û˘Ó., 1984)ÒÛÙ ӷ ÌËÓ ·ÏÏÔÈÒÓÔÓÙ·È ÔÈ È‰ÈfiÙËÙ˜ ÙÔ˘ Û‡ÚÌ·ÙÔ˜,ηıÒ˜ Ë ˘ÂÚı¤ÚÌ·ÓÛË ÙÔ Î·ıÈÛÙ¿ „·ı˘Úfi (BurstoneÎ·È Goldberg, 1980; Nelson Î·È Û˘Ó., 1987). ™‡ÌʈӷÌ ÚfiÛÊ·ÙË ÌÂϤÙË, Ù· Û‡ÚÌ·Ù· ‚-ÙÈÙ·Ó›Ô˘ ˘ÂÚÙÂÚÔ‡ÓÛÙÔÓ ÙÔ̤· Ù˘ ÈηÓfiÙËÙ·˜ ÚÔ˜ Û˘ÁÎfiÏÏËÛË ¤Ó·ÓÙÈ ÙˆÓÛ˘ÚÌ¿ÙˆÓ ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚·, ·ÊÔ‡ ·ÚÔ˘ÛÈ¿˙Ô˘ÓÌÂÁ·Ï‡ÙÂÚË ·ÓÙÔ¯‹ Î·È Î·Ï‡ÙÂÚ· ¯·Ú·ÎÙËÚÈÛÙÈο Ù˘ÂÈÊ¿ÓÂÈ·˜ Î·È Ù˘ ‰ÔÌ‹˜ ÙÔ˘˜, ÁÂÁÔÓfi˜ Ô˘ ˘Ô‰ËÏÒÓÂÈÂÏ¿¯ÈÛÙË ÌÂÙ·‚ÔÏ‹ ÙˆÓ È‰ÈÔÙ‹ÙˆÓ ÙÔ˘ Û‡ÚÌ·ÙÔ˜ ÌÂÙ¿ ÙËÛ˘ÁÎfiÏÏËÛË (Krishnan Î·È Kumar, 2004b).√È ÚÔ‚ÏËÌ·ÙÈÛÌÔ› ÂÚ› ‚ÈÔÛ˘Ì‚·ÙfiÙËÙ·˜ ÁÈ· Ù· Û‡ÚÌ·-Ù· ‚-ÙÈÙ·Ó›Ô˘ Â›Ó·È ÌÂȈ̤ÓÔÈ ÏfiÁˆ Ù˘ ·Ô˘Û›·˜ ÓÈÎÂÏ›-Ô˘ ·fi ·˘Ù¿, ·ÚfiÏÔ Ô˘ ¤¯Ô˘Ó ·ÚfiÌÔÈ· ·ÓÙ›ÛÙ·ÛËÛÙË ‰È¿‚ÚˆÛË Û ۯ¤ÛË Ì ٷ Û‡ÚÌ·Ù· ÎÔ‚·ÏÙ›Ô˘-¯Úˆ-Ì›Ô˘ Î·È ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚·. H ·ÓÙ›ÛÙ·Û‹ ÙÔ˘˜ ÛÙˉȿ‚ÚˆÛË ÔÊ›ÏÂÙ·È ÛÙÔ Û¯ËÌ·ÙÈÛÌfi ÂÓfi˜ ·ıËÙÈÎÔÔÈ-Ë̤ÓÔ˘ ÂÈÊ·ÓÂÈ·ÎÔ‡ ÛÙÚÒÌ·ÙÔ˜ ÔÍÂȉ›ˆÓ (Kim ηÈJohnson, 1999), ÂÓÒ Ú¤ÂÈ Ó· ÛËÌÂȈı› ˆ˜ Ë ¤ÎıÂÛËÛ ·Ú¿ÁÔÓÙ˜ ÊıÔÚ›Ô˘, Ô˘ ¯ÚËÛÈÌÔÔÈÔ‡ÓÙ·È Û˘¯Ó¿·fi ÙÔ˘˜ ÔÚıÔ‰ÔÓÙÈÎÔ‡˜ ·ÛıÂÓ›˜, Ô‰ËÁ› Û ·Ô‰ÈÔÚ-

two major phases are austenitic NiTi (austenite) at hightemperatures and martensitic NiTi (martensite) at lowtemperatures and high stress levels. The intermediatephase, the R phase delays the transition from austenite tomartensite upon cooling until lower temperatures areachieved (Gioka and Eliades, 2002).Upon heating, As and Af temperatures are those at whichthe transformation to austenite starts and finishes, respec-tively. Wire alloys with actual shape memory in vivo (suchas NeoSentalloy) have Af temperatures lower than oralcavity temperatures, therefore their structure is alwaysaustenitic during use. Non-superelastic (martensitic) wireswith no actual shape memory (such as Nitinol) have Aftemperatures much higher than 37 ÆC, therefore they havemicrostructures incompletely transformed to austenite atoral cavity temperatures. Copper nickel-titanium wires(Copper Ni-Ti) are available with three Af temperatures,27Æ, 35Æ, and 40ÆC. Therefore, the 27ÆC wire is useful inpeople with oral breathing, the 35ÆC wire is activated atnormal body temperature and the 40ÆC wire is only acti-vated upon consumption of hot foods and beverages.Finally, there are wires having a pseudo-elastic behavior,during which their martensitic structure is transformed toaustensitic as a result of stress from the activation of thewire. These wires (such as Nitinol SE) are superplastic, butdo not have a thermoelastic shape memory in vivo (Brant-ley, 2001).Superelastic NiTi wires also have a pure shape memoryand are highly sensitive to changes in temperature affect-ing their mechanical properties (Wilkinson et al., 2002; DeSantis et al., 2008). The stress of these wires is increasedwith heating and reduced with cooling (Meling and Ode-gaard 1998a; Airoldi et al., 1997; Sakima et al., 2006; Kusyand Whitley, 2007). According to a study by Kusy andWhitley (2007), the Orthonol (Rocky Mountain Orthodon-tics, Denver, CO, USA) and the three Cu-Ni-Tis demon-strate the stiffness of standard Nitinol at low tempera-tures developed in the oral cavity and the stiffness of TMAat high temperatures. With regard to the three types ofCu-Ni-Ti, their need to exist is questionable. A recent clin-ical trial failed to detect a significant difference in the cor-rection of crowding between standard Ni-Ti and Cu-Ni-Tiwires (Pandis et al., 2009). In the laboratory, the onlymajor difference is seen when placing the wire, where Cu-Ni-Ti 40ÆC applies a lower force and Cu-Ni-Ti 27Æ applies ahigher one (Wilkinson et al., 2002; Kusy and Whitley,2007). Therefore, it would be wrong to consider thatforces applied by superelastic wires to teeth during theiruse are constant. However, bone adaptation mechanismsinclude the mechanical signal transfer achieved throughdynamic, not static loadings (Gross et al., 2002). This mostlikely suggests that changing loadings of superelasticwires induced by temperature changes may, after all, bean advantage.

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H 2011 ñ TOMO™ 14 ñ TEYXO™ 1 53

Á¿ÓˆÛ‹ ÙÔ˘, ·ÎfiÏÔ˘ıË ‰È¿‚ÚˆÛË Î·È ÔÈÔÙÈ΋ ·ÏÏÔ›-ˆÛË Ù˘ ÂÈÊ¿ÓÂÈ·˜ ÙÔ˘ Û‡ÚÌ·ÙÔ˜ (Walker Î·È Û˘Ó.,2007). ¶ÂÈÚ·Ì·ÙÈΤ˜ ÌÂϤÙ˜ ¤¯Ô˘Ó ‰Â›ÍÂÈ ˆ˜ Ì ÙÔÓÙÚfiÔ ·˘Ùfi ÂËÚ¿˙ÔÓÙ·È ·ÚÓËÙÈο ÔÈ Ì˯·ÓÈΤ˜ ȉÈfiÙË-Ù˜ ·ÂÓÂÚÁÔÔ›ËÛ˘ ÙˆÓ Û˘ÁÎÂÎÚÈÌ¤ÓˆÓ Ù‡ˆÓ Û˘ÚÌ¿-ÙˆÓ ·ÏÏ¿ Î·È ÙˆÓ Û˘ÚÌ¿ÙˆÓ ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· ηÈNiTi (Kwon Î·È Û˘Ó., 2005; Walker Î·È Û˘Ó., 2005;Walker Î·È Û˘Ó., 2007). ™˘Á¯ÚfiÓˆ˜, ·˘Í¿ÓÂÙ·È Î·È Ë ·Â-Ï¢ı¤ÚˆÛË ÈfiÓÙˆÓ ·fi ·˘Ù¿ ÂÁ›ÚÔÓÙ·˜ ÚÔ‚ÏËÌ·ÙÈ-ÛÌÔ‡˜ Ô˘ ·ÊÔÚÔ‡Ó ı¤Ì·Ù· ‚ÈÔÛ˘Ì‚·ÙfiÙËÙ·˜. √ ¯ÚfiÓÔ˜Ù˘ ¤ÎıÂÛ˘ ÙˆÓ Û˘ÚÌ¿ÙˆÓ Û ·Ú¿ÁÔÓÙ˜ ÊıÔÚ›Ô˘ Ê·›-ÓÂÙ·È ˆ˜ ·›˙ÂÈ ÛËÌ·ÓÙÈÎfi ÚfiÏÔ (Ogawa Î·È Û˘Ó.,2004). øÛÙfiÛÔ, Ô ÌÂÁ·Ï‡ÙÂÚÔ˜ fiÁÎÔ˜ ‰Â‰ÔÌ¤ÓˆÓ Ô˘·ÊÔÚÔ‡Ó ÙËÓ Â›‰Ú·ÛË ·Ú·ÁfiÓÙˆÓ ÊıÔÚ›Ô˘ Û ˘ÏÈοÙÈÙ·Ó›Ô˘ ÚÔ¤Ú¯ÂÙ·È ·fi ÌÂϤÙ˜ Ô˘ ¤ÁÈÓ·Ó ÛÂ Û˘Óı‹Î˜in vitro Ì ˘ÂÚ·ÏÔ˘ÛÙÂ˘Ì¤Ó˜ ·Ú·‰Ô¯¤˜ Û¯ÂÙÈο ÌÂÙËÓ ÚÔÛÔÌÔ›ˆÛË ÙˆÓ Û˘ÓıËÎÒÓ Ù˘ ÛÙÔÌ·ÙÈ΋˜ ÎÔÈÏfi-ÙËÙ·˜. ∆· Â˘Ú‹Ì·Ù· ·˘Ù¿ ı· Ú¤ÂÈ Ó· ÂȂ‚·ÈˆıÔ‡Ó·fi in vivo ÌÂϤÙ˜ (Fragou Î·È Eliades, 2010).ªÂÈÔÓ¤ÎÙËÌ· ıˆÚÂ›Ù·È ÙÔ ˘„ËÏfi ÙÔ˘˜ ÎfiÛÙÔ˜ ηıÒ˜ ηÈË ÌÂÁ·Ï‡ÙÂÚË ÙÚÈ‚‹ ÛÙË ‰ÈÂÈÊ¿ÓÂÈ· Û‡ÚÌ·ÙÔ˜-·ÁÎ˘Ï›Ô˘·fi ÔÔÈÔ‰‹ÔÙ ¿ÏÏÔ ÎÚ¿Ì· (Kusy Î·È Whitley, 1989;Kapila Î·È Û˘Ó., 1990; Cash Î·È Û˘Ó., 2004; Krishnan ηÈKumar, 2004a), ·Ó Î·È Ì ÙËÓ ÂͤÏÈÍË ÙˆÓ Û˘ÚÌ¿ÙˆÓ ‚-ÙÈÙ·Ó›Ô˘, Ë ÔÈfiÙËÙ· ÙÔ˘ ÂÈÊ·ÓÂÈ·ÎÔ‡ ÙÂÏÂÈÒÌ·ÙÔ˜ ηÈÛ˘Ó·ÎfiÏÔ˘ı· ÔÈ ÙÈ̤˜ ÙÚÈ‚‹˜ Ê·›ÓÂÙ·È ˆ˜ ‚ÂÏÙÈÒÓÔ-ÓÙ·È (Kusy Î·È Û˘Ó., 2004). ¶ÚfiÛÊ·Ù· ΢ÎÏÔÊfiÚËÛ ¤Ó· Ó¤Ô Û‡ÚÌ· ·fi ÎÚ¿Ì·¿ÏÊ·-‚‹Ù· ÙÈÙ·Ó›Ô˘ Ô˘ ÔÓÔÌ¿˙ÂÙ·È TiMolium (TP Labs).™‡Ìʈӷ Ì ÙË ÌÂϤÙË ÙˆÓ Krishnan Î·È Kumar (2004a),Ë ·Î·Ì„›· ·ÏÏ¿ Î·È Ù· ˘fiÏÔÈ· ¯·Ú·ÎÙËÚÈÛÙÈο ÙÔ˘Û‡ÚÌ·ÙÔ˜ ·˘ÙÔ‡ (fiˆ˜ ̤ÙÚÔ ÂÏ·ÛÙÈÎfiÙËÙ·˜, fiÚÈÔ ‰È·Ú-ÚÔ‹˜) ‚Ú›ÛÎÔÓÙ·È ÌÂٷ͇ ÙˆÓ ÙÈÌÒÓ Ô˘ ÔÚÈÔıÂÙÔ‡Ó Ù·Û‡ÚÌ·Ù· ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· Î·È ‚‹Ù·-ÙÈÙ·Ó›Ô˘.

™™‡‡ÚÚÌÌ··ÙÙ·· ÓÓÈÈÎÎÂÂÏÏ››ÔÔ˘̆--ÙÙÈÈÙÙ··ÓÓ››ÔÔ˘̆ ‹‹ NNii--TTii∆Ô ÚÒÙÔ Û‡ÚÌ· ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘ (Nitinol) ·ÚÔ˘ÛÈ¿-ÛÙËΠÁÈ· ÔÚıÔ‰ÔÓÙÈ΋ ¯Ú‹ÛË ·fi ÙÔ˘˜ Andreasen ηÈHileman ÙÔ 1971. ∏ ÚÒÙË ÁÂÓÈ¿ ÎÚ·Ì¿ÙˆÓ NiTi ÂÌÊ¿ÓÈ-˙ ÙÔ ¯·Ú·ÎÙËÚÈÛÙÈÎfi ''ÌÓ‹Ì˘ Û¯‹Ì·ÙÔ˜'', ÙÔ ÔÔ›Ô ·Ó·-ʤÚÂÙ·È ÛÙËÓ ÈηÓfiÙËÙ· ÙÔ˘ Û‡ÚÌ·ÙÔ˜ Ó· ·ӤگÂÙ·È ÛÂÚÔηٷÛ΢·Ṳ̂ÓÔ Û¯‹Ì· ÌÂÙ¿ ·fi Ï·ÛÙÈ΋ ·Ú·-ÌfiÚʈÛË ÙÔ˘ fiÙ·Ó ÙÔ Û‡ÚÌ· ıÂÚÌ·Óı›. ∏ ·ӷÊÔÚ¿Û˘Ì‚·›ÓÂÈ ÂÓÙfi˜ ÂÓfi˜ ‡ÚÔ˘˜ ıÂÚÌÔÎÚ·Û›·˜ (transitionaltemperature range, TTR) (Andreasen Î·È Û˘Ó., 1985). ∏ȉÈfiÙËÙ· ·˘Ù‹ ÙÔ˘ Û‡ÚÌ·ÙÔ˜ ¯·Ú·ÎÙËÚ›ÛÙËΠ·fi ÙÔ˘˜Andreasen Î·È Û˘Ó. (1985) ''˘ÂÚÂÏ·ÛÙÈÎfiÙËÙ·''. ø˜ ˘Â-ÚÂÏ·ÛÙÈÎfiÙËÙ· ÔÚ›˙ÂÙ·È ÙÔ Ê·ÈÓfiÌÂÓÔ Î·Ù¿ ÙÔ ÔÔ›Ô ÙÔÛ‡ÚÌ· ·ÛΛ Ì›· ‹È·, Û˘Ó¯‹ ‰‡Ó·ÌË, Ì ''plateau''ηٿ ÙË ÊfiÚÙÈÛË ‹ ·ÔÊfiÚÙÈÛË ÙÔ˘ (πijima Î·È Û˘Ó.,

The most important advantage of NiTi wires is theirincreased elasticity allowing a wide deflection and activa-tion range by delivering low forces (Andreasen and Mor-row, 1978; Burstone et al., 1985). In general, nickel-titani-um wires have a higher energy storage capacity than beta-titanium or stainless steel wires when activated with thesame amount of bending or torque (Drake et al., 1982;Brantley, 2001). Moreover, for a given amount of activa-tion, they apply a lower and more constant force thanstainless steel or cobalt-chromium wires. However, thelevels of forces delivered vary significantly between NiTiwires from different manufacturers (Nakano et al., 1999).A study by Sakima et al. (2006) on 0.019 x 0.025-inch NiTiwires found that the lowest and most constant levels offorce are delivered by Copper NiTi 40ÆC and NeoSentalloy200 gr. However, it was pointed out that these wires donot deliver forces at a temperature below 35ÆC, therefore,they should not be used in subjects with oral breathing. Low formability of these wires is a disadvantage. Anydesirable bending should be performed to such an extentso as to achieve a permanent deflection rate. Moreover,these wires are often fractured when bent over a sharpedge (Andreasen and Morrow, 1978), whereas bendingalso adversely affects the spring-back of wires (Lopez etal., 1979). Furthermore, they are expensive and cannot bewelded or fused (Brantley, 2001). Nickel-titanium wiresdevelop an equally high bracket-wire friction to that ofbeta-titanium wires, which is higher than that of stainlesssteel or chromium-cobalt wires (Kapila et al., 1990).NiTi wires have a passivation oxide layer (titanium oxide),which is more stable than that formed on steel wires(chromium oxide) and provides them good corrosion resis-tance in the mildly acidic oral environment. However, itwas found that a low release of Ni or Ti ions may be seen(Huang et al., 2003). According to a study by Eliades et al.(2000), the intra-oral exposure of NiTi wires alters thetopography and structure of their surface. However, it hasnot been fully clarified whether this may be of clinical rel-evance, possibly affecting the wire’s superelastic proper-ties (Gioka and Eliades, 2002). It has been found that(stress) increases the corrosion rate of NiTi and beta-titani-um wires and that stress/deflection changes related to thephase transformation of superelastic NiTi wires may affecttheir corrosion rate in a way different than that of wiresnot subject to phase transformation (Segal et al., 2009).Additionally, the longer nickel-titanium wires remain inthe oral cavity, the more likely they are to fail due to nor-mal wear, whereas it seems that larger square- or rectan-gular-section wires are shown to be more vulnerable com-pared to smaller-section wires (Bourauel et al., 2008).Several clinical trials have shown that in many cases super-elastic wires are not capable of demonstrating their super-elastic properties in vivo, therefore, they do not have sig-nificant advantages over standard wires NiTi (Meling and

π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires HELLENIC ORTHODONTIC REVIEW

54 HELLENIC ORTHODONTIC REVIEW 2010 ñ VOLUME 13 ñ ISSUE 1 & 2

Odegaard, 1998a,b; Brantley, 2001).

MMuullttiissttrraannddeedd wwiirreessMultistranded wires are made of a varying number ofstainless steel wire strands coaxially placed or coiledaround each other in different configurations. The stiff-ness of a triple-stranded 0.0175-inch wire is comparable tothat of a single-stranded 0.010-inch stainless steel wire,whereas the triple-stranded is more resilient by 25%.Moreover, a triple-stranded 0.0175-inch wire has similarstiffness to that of a 0.016-inch nickel-titanium wire,although the nickel-titanium wire can accept more than50% greater activation than the multistranded one. Fur-thermore, the triple-stranded wire is 50% less stiff than a0.016-inch beta-titanium wire (Kusy and Dilley, 1984). Theelastic behavior of coiled multistranded wires resemblesmore the behavior of a single strand than of a set ofstrands (Rucker and Kusy, 2002a,b,d). Multistranded wires,such as nickel-titanium wires, have a spring-back, which israther independent of the wire’s size, as opposed to mul-tistranded stainless steel wires (Ingram et al., 1986; Kusyand Dilley, 1984; Kusy, 1981).Taneja et al. (2003), following a laboratory study of differ-ent multistranded stainless steel wires concluded thatalthough the arrangement, section, and number ofstrands should in theory greatly affect the range of forcesapplied in a given deflection (Rucker and Kusy, 2002d), inpractice, this only occurs in deflections over 2 mm. Addi-tionally, these investigators observed that coiled wiresdeliver higher forces than coaxial wires. Low forces developed by multistranded wires, low stiff-ness and a high spring-back are characteristics similar tothose of the more expensive titanium alloys (Wilkinson etal., 2002; Rucker Î·È Kusy, 2002a), and could be an eco-nomically advantageous alternative (Kusy and Dilley,1984; Kusy and Stevens, 1987). However, multistrandedwires do not always deliver low and rather constant forceswhen unloaded, particularly after significant deflection(Taneja et al., 2003). With regard to friction, multistrand-ed stainless steel wires develop higher bracket-wire fric-tion than NiTi wires and approximately more than 30%greater friction than single-stranded stainless steel wires(Rucker and Kusy, 2002c).

CCLLIINNIICCAALL AAPPPPLLIICCAATTIIOONNSS OOFF OORRTTHHOODDOONNTTIICC WWIIRREESS

The proper selection of the type and size of wire can max-imize efficiency of the clinical applications of orthodonticwires in a way that all clinical requirements are fulfilled.The wire sequence that is followed in the course of treat-ment is depended on the treatment technique (i.e., seg-mental or straight wire technique) and can be accordinglymodified. Knowledge of basic wire properties and biome-chanical aspects can help the orthodontist select the wire

2002). √ ÔÚÈÛÌfi˜ ·˘Ùfi˜ ‰fiıËΠ‚¿ÛÂÈ ÙˆÓ ‰ÔÌÈÎÒÓ·ÏÏ·ÁÒÓ Ô˘ Û˘Ì‚·›ÓÔ˘Ó ÛÙÔ Û‡ÚÌ· (ÌÂÙ·ÙÚÔ‹Ê¿Û˘) ηٿ ÙË ‰È¿ÚÎÂÈ· ÙˆÓ ıÂÚÌÔÎÚ·ÛÈ·ÎÒÓ ÌÂÙ·‚Ô-ÏÒÓ ‹ Ù˘ ‰È·‰Èηۛ·˜ ÊfiÚÙÈÛ˘ ÙÔ˘ (Meling ηÈOdegaard, 2001).∆Ô 1985 ÚÔÙ¿ıËΠ·fi ÙÔ˘˜ Burstone Î·È Û˘Ó. ÙÔ ÎÈÓ¤-˙ÈÎÔ NiTi (Ormco, Orange, CA, USA) Ô˘ ÂÌÊ¿ÓÈ˙ 4,4ÊÔÚ¤˜ ÙËÓ ÈηÓfiÙËÙ· ·ӷÊÔÚ¿˜ ÙÔ˘ Û‡ÚÌ·ÙÔ˜ ·ÓÔÍ›-‰ˆÙÔ˘ ¯¿Ï˘‚· Î·È 1,6 ÊÔÚ¤˜ ÙËÓ ÈηÓfiÙËÙ· ·ӷÊÔÚ¿˜ÙÔ˘ ·Ú¯ÈÎÔ‡ Nitinol Î·È ·Ú›¯Â ÛÙ·ıÂÚ‹ ‰‡Ó·ÌË ÛÙÔ̤ÛÔ ÙÔ˘ ‡ÚÔ˘˜ ·ÂÓÂÚÁÔÔ›ËÛ˘ ÙÔ˘ (Bradley ηÈÛ˘Ó., 1996). ŒÓ· ¯ÚfiÓÔ ·ÚÁfiÙÂÚ· ·ÚÔ˘ÛÈ¿ÛÙËΠ·fiÙÔ˘˜ Miura Î·È Û˘Ó. (1986), ÙÔ È·ˆÓÈÎfi NiTi (SentalloyDENTSPLY GAC International, Bohemia, NY) Ì ·Úfi-ÌÔȘ ȉÈfiÙËÙ˜ (Brantley Î·È Û˘Ó., 1997). ∆¤ÏÔ˜, ÛÙËÓ·Ú¯‹ Ù˘ ‰ÂηÂÙ›·˜ ÙÔ˘ ã90 ·ÚÔ˘ÛÈ¿ÛÙËΠ·fi ÙËÓ GAC¤Ó· Ó¤Ô Û‡ÚÌ· (NeoSentalloy) Ô˘ ‰È·ı¤ÙÂÈ ·ÌÈÁ‹ ÌÓ‹ÌËÛ¯‹Ì·ÙÔ˜ ÛÙË ıÂÚÌÔÎÚ·Û›· ÙÔ˘ ÛÙfiÌ·ÙÔ˜ Î·È ÙËÓ ›‰È·‰ÂηÂÙ›· Ù· CuNiTi ·fi ÙËÓ Ormco (Gioka Î·È Eliades,2002).ŸÛÔÓ ·ÊÔÚ¿ ÙË ÌÂÙ·ÏÏÔ˘ÚÁÈ΋ ‰ÔÌ‹ ÙˆÓ ÎÚ·Ì¿ÙˆÓNiTi, ·Ó·ÁÓˆÚ›˙ÔÓÙ·È ‰‡Ô ·ÚȘ Î·È Ì›· ÂӉȿÌÂÛËÊ¿ÛË. √È Î‡ÚȘ Ê¿ÛÂȘ Â›Ó·È ÙÔ ˆÛÙÂÓÈÙÈÎfi NiTi (ˆÛÙÂÓ›-Ù˘) Ô˘ ÂÌÊ·Ó›˙ÂÙ·È Û ˘„ËϤ˜ ıÂÚÌÔÎڷۛ˜ Î·È ÌÈÎÚ¤˜Ù¿ÛÂȘ Î·È ÙÔ Ì·ÚÙÂÓÛÈÙÈÎfi NiTi (Ì·ÚÙÂÓÛ›Ù˘) Ô˘ ˘Ê›-ÛÙ·Ù·È Û ¯·ÌËϤ˜ ıÂÚÌÔÎڷۛ˜ Î·È ÌÂÁ¿Ï˜ Ù¿ÛÂȘ. ∏ÂӉȿÌÂÛË Ê¿ÛË, Ê¿ÛË R, ηı˘ÛÙÂÚ› ÙË ÌÂÙ·ÙÚÔ‹ ÙÔ˘ˆÛÙÂÓÛ›ÙË Û ̷ÚÙÂÓÛ›ÙË Î·Ù¿ ÙËÓ „‡ÍË Ì¤¯ÚÈ Ó· ÂÈÙ¢-¯ıÔ‡Ó ¯·ÌËÏfiÙÂÚ˜ ıÂÚÌÔÎڷۛ˜ (Gioka Î·È Eliades,2002).∫·Ù¿ ÙË ı¤ÚÌ·ÓÛË, ÔÈ ıÂÚÌÔÎڷۛ˜ As Î·È Af Â›Ó·È ·ÓÙ›-ÛÙÔȯ· ÔÈ ıÂÚÌÔÎڷۛ˜ ¤Ó·Ú͢ Î·È ÔÏÔÎÏ‹ÚˆÛ˘ Ù˘ÌÂÙ·‚ÔÏ‹˜ Û ˆÛÙÂÓ›ÙË. ∆· ÎÚ¿Ì·Ù· Û˘ÚÌ¿ÙˆÓ Ì ڷÁ-Ì·ÙÈ΋ ÌÓ‹ÌË Û¯‹Ì·ÙÔ˜ in vivo (fiˆ˜ ÙÔ NeoSentalloy)¤¯Ô˘Ó ıÂÚÌÔÎڷۛ˜ Af ¯·ÌËÏfiÙÂÚ˜ ·fi ÙË ıÂÚÌÔÎÚ·-Û›· ÙÔ˘ ÛÙfiÌ·ÙÔ˜ Î·È ¤ÙÛÈ ¤¯Ô˘Ó ¿ÓÙÔÙ ˆÛÙÂÓÈ΋ ‰Ô̋ηٿ ÙË ¯Ú‹ÛË ÙÔ˘˜. ∆· ÌË ˘ÂÚÂÏ·ÛÙÈο Û‡ÚÌ·Ù· (Ì·Ú-ÙÂÓÛÈÙÈο), Ô˘ ‰Â ‰È·ı¤ÙÔ˘Ó ·ÏËı‹ ÌÓ‹ÌË Û¯‹Ì·ÙÔ˜(fiˆ˜ ÙÔ Nitinol), ¤¯Ô˘Ó ıÂÚÌÔÎڷۛ˜ Af ·ÚÎÂÙ¿ ÌÂÁ·-χÙÂÚ˜ ·fi 37 ÆC Ì ·ÔÙ¤ÏÂÛÌ· Ó· ‰È·ı¤ÙÔ˘Ó ÌÈÎÚÔ-‰Ô̤˜ Ô˘ ¤¯Ô˘Ó ·ÙÂÏÒ˜ ÌÂÙ·Ùڷ› Û ˆÛÙÂÓ›ÙË ÛÙËıÂÚÌÔÎÚ·Û›· ÙÔ˘ ÛÙfiÌ·ÙÔ˜. ∆· Û‡ÚÌ·Ù· ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›-Ô˘ Ì ¯·ÏÎfi (Copper Ni-Ti) ‰È·Ù›ıÂÓÙ·È Ì ÙÚÂȘ ıÂÚÌÔ-Îڷۛ˜ Af, 27Æ, 35Æ Î·È 40ÆC. ™˘ÓÂÒ˜, ÙÔ Û‡ÚÌ· ÙˆÓ27ÆC Â›Ó·È ¯Ú‹ÛÈÌÔ Û ¿ÙÔÌ· Ì ÛÙÔÌ·ÙÈ΋ ·Ó·ÓÔ‹, ÙÔÛ‡ÚÌ· ÙˆÓ 35ÆC ÂÓÂÚÁÔÔÈÂ›Ù·È ÛÂ Ê˘ÛÈÔÏÔÁÈ΋ ıÂÚÌÔ-ÎÚ·Û›· ÛÒÌ·ÙÔ˜ Î·È ÙÔ Û‡ÚÌ· ÙˆÓ 40ÆC ÂÓÂÚÁÔÔÈ›ٷÈÌfiÓÔ ÌÂÙ¿ ·fi ηٷӿψÛË ˙ÂÛÙÒÓ ÙÚÔÊÒÓ Î·È ÔÙÒÓ.∆¤ÏÔ˜, ˘¿Ú¯Ô˘Ó Î·È Ù· Û‡ÚÌ·Ù· Ô˘ ÂÌÊ·Ó›˙Ô˘Ó „¢-‰ÔÂÏ·ÛÙÈ΋ Û˘ÌÂÚÈÊÔÚ¿, ηٿ ÙËÓ ÔÔ›· Ë ÌÂÙ·‚ÔÏ‹

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H 2011 ñ TOMO™ 14 ñ TEYXO™ 1 55

Ù˘ Ì·ÚÙÂÓÛÈÙÈ΋˜ ‰ÔÌ‹˜ ÙÔ˘˜ Û ˆÛÙÂÓÛÈÙÈ΋ ÚÔηÏ›-Ù·È ·fi ÙË ‰ËÌÈÔ˘ÚÁ›· Ù¿ÛÂˆÓ Ô˘ ·Ó·Ù‡ÛÛÔÓÙ·È Î·Ù¿ÙËÓ ÂÓÂÚÁÔÔ›ËÛË ÙÔ˘ Û‡ÚÌ·ÙÔ˜. ∆· Û‡ÚÌ·Ù· ·˘Ù¿(fiˆ˜ ÙÔ Nitinol SE) Â›Ó·È ˘ÂÚÂÏ·ÛÙÈο, ·ÏÏ¿ ‰ÂÓ ‰È·-ı¤ÙÔ˘Ó ıÂÚÌÔÂÏ·ÛÙÈ΋ ÌÓ‹ÌË Û¯‹Ì·ÙÔ˜ in vivo(Brantley, 2001).∆· ˘ÂÚÂÏ·ÛÙÈο Û‡ÚÌ·Ù· NiTi Î·È ·˘Ù¿ Ì ·ÏËı‹ ÌÓ‹ÌËÛ¯‹Ì·ÙÔ˜ ÂÌÊ·Ó›˙Ô˘Ó ÌÂÁ¿ÏË Â˘·ÈÛıËÛ›· ÛÙȘ ÌÂÙ·‚Ô-Ϥ˜ Ù˘ ıÂÚÌÔÎÚ·Û›·˜, ÔÈ Ôԛ˜ ÂËÚ¿˙Ô˘Ó ÙȘ Ì˯·ÓÈ-Τ˜ ÙÔ˘˜ ȉÈfiÙËÙ˜ (Wilkinson Î·È Û˘Ó., 2002; De SantisÎ·È Û˘Ó., 2008). ∏ Ù¿ÛË ÙˆÓ Û˘ÚÌ¿ÙˆÓ ·˘ÙÒÓ ·˘Í¿ÓÂÙ·ÈÌ ÙË ı¤ÚÌ·ÓÛË Î·È ÌÂÈÒÓÂÙ·È Ì ÙËÓ „‡ÍË (Meling ηÈOdegaard 1998a; Airoldi Î·È Û˘Ó., 1997; Sakima ηÈÛ˘Ó., 2006; Kusy Î·È Whitley, 2007). ™‡Ìʈӷ Ì ÌÂϤ-ÙË ÙˆÓ Kusy Î·È Whitley (2007), ÙÔ Orthonol (RockyMountain Orthodontics, Denver, CO, USA) Î·È Ù· ÙÚ›·Cu-Ni-Ti ÂÌÊ·Ó›˙Ô˘Ó ÙËÓ ·Î·Ì„›· ÙÔ˘ ÎÏ·ÛÛÈÎÔ‡ NitinolÛ ¯·ÌËϤ˜ ıÂÚÌÔÎڷۛ˜ Ô˘ ·Ó·Ù‡ÛÛÔÓÙ·È ÛÙËÓ ÛÙÔ-Ì·ÙÈ΋ ÎÔÈÏfiÙËÙ· Î·È ÙËÓ ·Î·Ì„›· ÙÔ˘ TMA Û ˘„ËϤ˜ıÂÚÌÔÎڷۛ˜. ŸÛÔÓ ·ÊÔÚ¿ ÙÔ˘˜ ÙÚÂȘ Ù‡Ô˘˜ Cu-Ni-Ti,Ë ·Ó¿ÁÎË Ù˘ ‡·ÚÍ‹˜ ÙÔ˘˜ ·ÌÊÈÛ‚ËÙ›ٷÈ. ¶ÚfiÛÊ·ÙËÎÏÈÓÈ΋ ÌÂϤÙË ‰ÂÓ ÂÓÙfiÈÛ ÛËÌ·ÓÙÈ΋ ‰È·ÊÔÚ¿ ÛÙˉÈfiÚıˆÛË ÙÔ˘ Û˘ÓˆÛÙÈÛÌÔ‡ ÌÂٷ͇ Û˘Ì‚·ÙÈÎÒÓ Ni-TiÎ·È Cu-Ni-Ti Û˘ÚÌ¿ÙˆÓ (Pandis Î·È Û˘Ó., 2009). ∂ÚÁ·-ÛÙËÚȷο, Ë ÌfiÓË ÛËÌ·ÓÙÈ΋ ‰È·ÊÔÚ¿ ·Ú·ÙËÚÂ›Ù·È Î·Ù¿ÙËÓ ÙÔÔı¤ÙËÛË ÙÔ˘ Û‡ÚÌ·ÙÔ˜, fiÔ˘ ÙÔ Cu-Ni-Ti 40ÆC·ÛΛ ÙË ÌÈÎÚfiÙÂÚË ‰‡Ó·ÌË Î·È ÙÔ Cu-Ni-Ti 27Æ ÙË ÌÂÁ·-χÙÂÚË (Wilkinson Î·È Û˘Ó., 2002; Kusy Î·È Whitley,2007). ™˘ÓÂÒ˜, Â›Ó·È Ï¿ıÔ˜ Ó· ıˆÚԇ̠fiÙÈ ÔÈ ‰˘Ó¿-ÌÂȘ Ô˘ ·ÛÎÔ‡Ó Ù· ˘ÂÚÂÏ·ÛÙÈο Û‡ÚÌ·Ù· ÛÙ· ‰fiÓÙȷηٿ ÙË ¯Ú‹ÛË ÙÔ˘˜ Â›Ó·È ÛÙ·ıÂÚ¤˜. øÛÙfiÛÔ, ÔÈ Ì˯·ÓÈ-ÛÌÔ› ÚÔÛ·ÚÌÔÁ‹˜ ÙÔ˘ ÔÛÙÔ‡ ÂÚÈÏ·Ì‚¿ÓÔ˘Ó ÌÈ· ‰È·‰È-ηۛ· Ì˯·ÓÈ΋˜ ÌÂÙ·ÁˆÁ‹˜ ÛËÌ¿ÙˆÓ Ô˘ ÂÈÙÂÏ›ٷȷfi ‰˘Ó·ÌÈΤ˜ Î·È fi¯È ·fi ÛÙ·ÙÈΤ˜ ÊÔÚÙ›ÛÂȘ (Gross ηÈÛ˘Ó., 2002). ∞˘Ùfi Èı·Ófiٷٷ ˘Ô‰ËÏÒÓÂÈ ˆ˜ ÔÈ ÌÂÙ·-‚·ÏÏfiÌÂÓ˜ ÊÔÚÙ›ÛÂȘ ÙˆÓ ˘ÂÚÂÏ·ÛÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓÔ˘ ¿ÁÔÓÙ·È ·fi ıÂÚÌÔÎÚ·ÛȷΤ˜ ÌÂÙ·‚ÔϤ˜ ›Ûˆ˜ÙÂÏÈο ·ÔÙÂÏÔ‡Ó ÏÂÔÓ¤ÎÙËÌ·.∆Ô ÛËÌ·ÓÙÈÎfiÙÂÚÔ ÏÂÔÓ¤ÎÙËÌ· ÙˆÓ Û˘ÚÌ¿ÙˆÓ NiTi ›ӷÈË ·˘ÍË̤ÓË ÂÏ·ÛÙÈÎfiÙËÙ· Ô˘ ÂÈÙÚ¤ÂÈ ÌÂÁ¿ÏÔ Â‡ÚÔ˜ÂÏ·ÛÙÈ΋˜ ·Ú·ÌfiÚʈÛ˘ Î·È ÂÓÂÚÁÔÔ›ËÛ˘, ·Ô‰›‰Ô-ÓÙ·˜ ‹È˜ ‰˘Ó¿ÌÂȘ (Andreasen Î·È Morrow, 1978;Burstone Î·È Û˘Ó., 1985). °ÂÓÈο, Ù· Û‡ÚÌ·Ù· ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘ ¤¯Ô˘Ó ÌÂÁ·Ï‡ÙÂÚË ‰˘Ó·ÙfiÙËÙ· ÁÈ· ·fi‰ÔÛË·ÔıËÎÂ˘Ì¤Ó˘ ÂÓ¤ÚÁÂÈ·˜ Û ۇÁÎÚÈÛË Ì ٷ Û‡ÚÌ·Ù· ‚-ÙÈÙ·Ó›Ô˘ ‹ ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· fiÙ·Ó ÂÓÂÚÁÔÔÈÔ‡ÓÙ·ÈÌ ÙÔ ›‰ÈÔ ÔÛfi ο̄˘ ‹ ÛÙÚ¤„˘ (Drake Î·È Û˘Ó., 1982;Brantley, 2001). ∂›Û˘, ÁÈ· ‰Â‰Ô̤ÓÔ ÔÛfi ÂÓÂÚÁÔÔ›Ë-Û˘, ·ÛÎÔ‡Ó ËÈfiÙÂÚË Î·È ÂÚÈÛÛfiÙÂÚÔ ÛÙ·ıÂÚ‹ ‰‡Ó·ÌË·fi fiÙÈ ·˘Ù¿ ·fi ·ÓÔÍ›‰ˆÙÔ ¯¿Ï˘‚· ‹ Ù· ÎÔ‚·ÏÙ›Ô˘-

material, geometry and size that is optimal for each caseor make various technique combinations that will opti-mize the quality of the treatment provided. Usually, in theinitial stages of orthodontic treatment the most commonwires used are superelastic NiTi wires that are replaced bybeta- titanium and stainless steel wires later in treatment(Keim et al., 2002). The high modulus of elasticity of Co-Crand stainless steel wires implies that this type of wiresexert twice the force of beta- titanium and 4 times theforce of the conventional NiTi wires for the same amountof activation (Drake et al., 1982).Studies on the elastic properties of the wires specify thattheir mechanical behavior is determined by the followingequation: strength = stiffness x range (Kusy and Green-berg, 1981). For all the wires that follow linear elasticitythese characteristics are specified as following: (1)strength: the maximum force that can cause elastic defor-mation of the wire, (2) stiffness: the strength to rangeratio, that is equal to force per activation unit and (3)range: the maximum distance that a wire can be elastical-ly activated. For all wires, except for some specific types ofNiTi wires, the relationship between force and elasticdeformation is linear (Zufall and Kusy. 2000a). It must beemphasized that all three elastic properties of the wires(strength, stiffness, range) depend on changes of thegeometry, the size and the length of the wire. For themajority of the conventional wires, flexibility and workingrange are decreased by increases in size, in contrast tostiffness that is increased. This is not the always the casefor multistranded stainless steel wires and especially forsuperelastic NiTi wires (Ingram et al., 1986). For all otherwires changes that are related to size and shape are of thesame degree irrespective of the construction material. Forexample, half reducing the diameter of a stainless steelwill accordingly reduce its stiffness to a specific percent-age of the initial stiffness. The same will happen for abeta- titanium wire: half reducing its diameter will givethe same percentile reduction of its initial stiffness as forthe stainless steel wire (Proffit et al., 2007). In addition,increasing the length of the wire will proportionallydecrease the stiffness but exponentially increase the elas-ticity and working range. Finally resilience is significantlyincreased when the wire is loosely ligated into the brack-ets allowing some sliding freedom ( Adams et al., 1987).It must be emphasized that rounding the edges of rectan-gular wires seriously reduces torque control and stiffness.Torque control depends on multiple factors that are relat-ed to the bracket and its design, the type of ligation, thefree-space (play) between the wire and the bracket slot.The raw material, the wire section and the edge bevelappear to play a significant role (Sebanc et al., 1984; Giokaand Eliades, 2004; Morina et al., 2008). In small activations(<12Æ) no difference was noted in torque expressionbetween stainless steel, TMA and Cu-Ni-Ti wires, whether

π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires HELLENIC ORTHODONTIC REVIEW

56 HELLENIC ORTHODONTIC REVIEW 2010 ñ VOLUME 13 ñ ISSUE 1 & 2

in higher angles (>24Æ) stainless steel wires express 1.5-2times and 2.5-3 times higher forces than TMA and Cu-Ni-Ti respectively (Archambault et al., 2010). It was foundthat superelasticity expression of NiTi wires at torsion inmouth temperature starts at 20 degrees, even thoughlarge variations appear depending on the manufacturer.This evidence, in conjunction with the free play of the wireinside the bracket slot, makes the clinical determination ofthe relationship between the NiTi wire cross section andthe real torsion force extremely difficult (Partowi et al.,2010).According to Burstone (1981), the desirable stepwiseincrease in wire stiffness in the treatment progress can beattainted not only by proper wire configuration and sizeincrease, but by the selection of higher modulus of elas-ticity wires as well (Variable- modulus orthodontics). Vari-ous laboratory studies have shown that the expressedforce and stiffness of the wire vary proportionally (Ruckerand Kusy, 2002a, b; Garrec et al., 2005). The stiffness cor-relation of Cr-Co, SS, beta-Ti and NiTi wires is1.2:1:0.42:0.26. The stiffness of multistranded wires is1/25-1/5 the stiffness of a single strand stainless steel wire(Burtsone, 1981). This allows the clinician to use bigger,even square or rectangular wires, in earlier treatmentstages giving better three dimensional control of themovements. Furthermore, according to Kusy (1997), keep-ing relatively constant the angular relationship betweenthe wire and the bracket slot helps in controlling theamount of friction. However, even though low stiffnessand wide working range are desirable properties duringtooth movement, the wire action in areas where no move-ment is expected, as in the final stages of treatment, isbetter controlled with wires that have narrower activationrange and higher stiffness (Burstone, 1985).During the initial stages of treatment wires with widerange of activation and low force delivery are preferred inorder to level and align the teeth (Kusy, 1997). Typicallythe clinician selects a wire of low stiffness, high resilienceand satisfactory strength (Rucker and Kusy, 2002b). Thefirst wire to be selected should express the maximumforce that can be tolerated once attached at the point-bracket of maximum activation (Johnson, 2003). Theoreti-cally, the initial wires should be round superelastic NiTiwires of small diameter, that can later on be replaced byrectangular NiTi wires which are relatively stiffer. NiTiwires have high resilience that allows a wide range ofelastic deformation and activation (Andreasen anf Mor-row, 1978; Drake et al., 1982; Brantley, 2001) and theyapply lower and more constant force in comparison tostainless steel or cobalt-chromium wires for a givenamount of activation. According to Andreasen and Mor-row (1987), the clinical advantages of NiTi wires includeless wire changes, less chair time, faster leveling and rota-tion correction and higher comfort for the patient. It is

¯ÚˆÌ›Ô˘. øÛÙfiÛÔ, Ù· ›‰· ÙˆÓ ‰˘Ó¿ÌÂˆÓ Ô˘·ÛÎÔ‡ÓÙ·È ÔÈΛÏÔ˘Ó ÛËÌ·ÓÙÈο ÌÂٷ͇ ÙˆÓ Û˘ÚÌ¿ÙˆÓNiTi ·fi ‰È·ÊÔÚÂÙÈÎÔ‡˜ ηٷÛ΢·ÛÙ¤˜ (Nakano ηÈÛ˘Ó., 1999). ™Â ÌÂϤÙË ÙˆÓ Sakima Î·È Û˘Ó. (2006) ÛÂÛ‡ÚÌ·Ù· NiTi ‰È·ÛÙ¿ÛÂˆÓ 0,019 x 0,025 ÈÓÙÛÒÓ, ‚Ú¤ıË-Πˆ˜ Ù· ¯·ÌËÏfiÙÂÚ· Î·È ÂÚÈÛÛfiÙÂÚÔ ÛÙ·ıÂÚ¿ ›‰·‰˘Ó¿ÌÂˆÓ ·ÛÎÔ‡Ó Ù· Copper NiTi 40ÆC ηÈNeoSentalloy 200 gr. ŸÌˆ˜, ÙÔÓ›ÛÙËΠˆ˜ Ù· Û‡ÚÌ·Ù··˘Ù¿ ‰ÂÓ ·ÛÎÔ‡Ó ‰˘Ó¿ÌÂȘ Û ıÂÚÌÔÎÚ·Û›· οو ·fi35ÆC Î·È ÁÈ'·˘Ùfi ‰ÂÓ ı· Ú¤ÂÈ Ó· ¯ÚËÛÈÌÔÔÈÔ‡ÓÙ·È Û¿ÙÔÌ· Ì ÛÙÔÌ·ÙÈ΋ ·Ó·ÓÔ‹. ªÂÈÔÓ¤ÎÙËÌ· ·ÔÙÂÏ› Ë ÌÈÎÚ‹ ÈηÓfiÙËÙ· ‰È·ÌfiÚʈÛË˜ÙˆÓ Û˘ÚÌ¿ÙˆÓ ·˘ÙÒÓ. √ÔÈ·‰‹ÔÙ ÂÈı˘ÌËÙ‹ ο̄Ëı· Ú¤ÂÈ Ó· ÂÈÙÂÏÂÛÙ› Û ·ÚÎÂÙ¿ ÌÂÁ·Ï‡ÙÂÚÔ ‚·ıÌfiÁÈ· Ó· ·Ú·Ì›ÓÂÈ Î¿ÔÈÔ ÔÛÔÛÙfi ÌfiÓÈÌ˘ ·Ú·ÌfiÚ-ʈÛ˘. ∞ÎfiÌË, Ù· Û‡ÚÌ·Ù· ·˘Ù¿ ·ÚÔ˘ÛÈ¿˙Ô˘Ó Û˘¯Ó¿Î·Ù¿ÁÌ·Ù· fiÙ·Ó Î¿ÌÙÔÓÙ·È Û ¤ÓÙÔÓ˜ ·Î̤˜(Andreasen Î·È Morrow, 1978), ÂÓÒ Ë Î¿Ì„Ë Âȉڿ·ÚÓËÙÈο Î·È ÛÙÔ Â‡ÚÔ˜ ÂÓÂÚÁÔÔ›ËÛ˘ ÙˆÓ Û˘ÚÌ¿ÙˆÓ(Lopez Î·È Û˘Ó., 1979). ∂›Û˘, Â›Ó·È ·ÎÚÈ‚¿ Î·È ‰ÂÓ ÌÔ-ÚÔ‡Ó Ó· ˘ÔÛÙÔ‡Ó Û˘ÁÎfiÏÏËÛË ‹ Ù‹ÍË (Brantley, 2001).∆· Û‡ÚÌ·Ù· ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘ ·Ó·Ù‡ÛÛÔ˘Ó ÂÍ›ÛÔ˘˘„ËÏ‹ ÙÚÈ‚‹ ÛÙË ‰ÈÂÈÊ¿ÓÂÈ· Û‡ÚÌ·ÙÔ˜ ·ÁÎ˘Ï›Ô˘ Ì·˘Ù‹ ÙˆÓ Û˘ÚÌ¿ÙˆÓ ‚-ÙÈÙ·Ó›Ô˘, Ô˘ Â›Ó·È ÌÂÁ·Ï‡ÙÂÚË ÛÂÛ¯¤ÛË Ì ۇÚÌ·Ù· ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· ‹ ¯ÚˆÌ›Ô˘-ÎÔ‚·ÏÙ›Ô˘ (Kapila Î·È Û˘Ó., 1990).∆· Û‡ÚÌ·Ù· NiTi ‰È·ı¤ÙÔ˘Ó ÂÈÊ·ÓÂÈ·Îfi ÛÙÚÒÌ· ·ıËÙÈ-ÎÔÔ›ËÛ˘ ÔÍÂȉ›ˆÓ (ÔÍ›‰ÈÔ ÙÔ˘ ÙÈÙ·Ó›Ô˘) ÙÔ ÔÔ›Ô Â›Ó·ÈÛÙ·ıÂÚfiÙÂÚÔ ·fi ÙÔ ·ÓÙ›ÛÙÔÈ¯Ô Ô˘ ‰ËÌÈÔ˘ÚÁÂ›Ù·È ÛÙ·Û‡ÚÌ·Ù· ¯¿Ï˘‚· (ÔÍ›‰ÈÔ ÙÔ˘ ¯ÚˆÌ›Ô˘) Î·È Ô˘ ÙÔ˘˜·Ú¤¯ÂÈ Î·Ï‹ ·ÓÙ›ÛÙ·ÛË ÛÙË ‰È¿‚ÚˆÛË ÛÙÔ ÂÏ·ÊÚ¿fiÍÈÓÔ ÛÙÔÌ·ÙÈÎfi ÂÚÈ‚¿ÏÏÔÓ. øÛÙfiÛÔ, ‰È·ÈÛÙÒıËΠfiÙÈÌÔÚ› Ó· ·Ú·ÙËÚËı› ÌÈÎÚÔ‡ ‚·ıÌÔ‡ ·ÂÏ¢ı¤ÚˆÛËÈfiÓÙˆÓ Ni ‹ Ti (Huang Î·È Û˘Ó., 2003). ™‡Ìʈӷ ÌÂÌÂϤÙË ÙˆÓ Eliades Î·È Û˘Ó. (2000), Ë ÂÓ‰ÔÛÙÔÌ·ÙÈ΋¤ÎıÂÛË ÙˆÓ Û˘ÚÌ¿ÙˆÓ NiTi ·ÏÏÔÈÒÓÂÈ ÙËÓ ÙÔÔÁÚ·Ê›·Î·È ÙË ‰ÔÌ‹ Ù˘ ÂÈÊ¿ÓÂÈ·˜ ÙÔ˘˜. øÛÙfiÛÔ, ‰ÂÓ ¤¯ÂÈ ·Ô-Û·ÊËÓÈÛÙ› Ï‹Úˆ˜ ÙÔ Î·Ù¿ fiÛÔ ·˘Ùfi ÌÔÚ› Ó· ·ÔÙÂ-Ï› ¤Ó· Ê·ÈÓfiÌÂÓÔ Ì ÎÏÈÓÈ΋ ÛËÌ·Û›·, ÂËÚ¿˙ÔÓÙ·˜Èı·ÓÒ˜ ÙȘ ˘ÂÚÂÏ·ÛÙÈΤ˜ ȉÈfiÙËÙ˜ ÙÔ˘ Û‡ÚÌ·ÙÔ˜(Gioka Î·È Eliades, 2002). µÚ¤ıËΠˆ˜ Ë Ù¿ÛË (stress)·˘Í¿ÓÂÈ ÙÔÓ Ú˘ıÌfi ‰È¿‚ÚˆÛ˘ Û˘ÚÌ¿ÙˆÓ NiTi Î·È ‚-ÙÈÙ·-Ó›Ô˘ Î·È ˆ˜ ÔÈ ÌÂÙ·‚ÔϤ˜ Ù¿Û˘/·Ú·ÌfiÚʈÛ˘ Ô˘Û¯ÂÙ›˙ÔÓÙ·È Ì ÌÂÙ·ÙÚÔ‹ Ê¿Û˘ ÙˆÓ ˘ÂÚÂÏ·ÛÙÈÎÒÓÛ˘ÚÌ¿ÙˆÓ ¡iTi ›Ûˆ˜ ÂËÚ¿˙Ô˘Ó ÙÔ Ú˘ıÌfi ‰È¿‚ÚˆÛ‹˜ÙÔ˘˜ ‰È·ÊÔÚÂÙÈο Û ۇÁÎÚÈÛË Ì ۇÚÌ·Ù· Ô˘ ‰ÂÓ ˘fi-ÎÂÈÓÙ·È Û ÌÂÙ·ÙÚÔ‹ Ê¿Û˘ (Segal Î·È Û˘Ó., 2009). ∂È-ÚfiÛıÂÙ·, Ô ÌÂÁ¿ÏÔ˜ ¯ÚfiÓÔ˜ ·Ú·ÌÔÓ‹˜ ÙˆÓ Û˘ÚÌ¿ÙˆÓÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘ ÂÓ‰ÔÛÙÔÌ·ÙÈο Û¯ÂÙ›˙ÂÙ·È Ì ÌÂÁ·Ï‡ÙÂ-ÚË Èı·ÓfiÙËÙ· ·ÔÙ˘¯›·˜ ÏfiÁˆ ηٷfiÓËÛ˘, ÂÓÒ Ê·›-

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H 2010 ñ TOMO™ 13 ñ TEYXO™ 1 & 2 57

suggested that the use of rectangular wires that fit firmlyin the slots of the brackets should be avoided during theinitial leveling and alignment of the teeth because itresults in undesirable "reciprocal" movements of theroots, thus increasing treatment time and root resorptionrisk. During this phase it is preferred that the crowns ofthe teeth are first arranged with the use of low diameterround wires (Proffit et al., 2007). Then, rectangular NiTiwires of higher cross section can be used, in early stagesof treatment, that will allow leveling, alignment, rotationcorrection and torque control at the same time.In particular cases, intermediate sizes of Australian wirescan be used in this phase for the correction of incisorsoverbite (utility arches or reverse curve of Spee arches),especially because of their high resistance to plastic defor-mation from external factors, like mastication forces(Drake et al., 1982). The high modulus of elasticity andstiffness of these wires dictate that wires of smaller diam-eter or of increased length, by means of forming loops,should be used for the alignment and leveling of the den-tal arches (Krishnan and Kumar, 2004a; Verstrynge et al.,2006).Whatever wire is selected for the initial alignment ofteeth, it should be loosely ligated so that the wire is freeto slide inside the bracket slots. In that way this particularstage of treatment appears to be significantly faster. Superelastic NiTi wires and wires that express shape mem-ory are useful in cases where large amounts of deforma-tion are needed in order to insert the wire in the brackets,as in high crowding cases (Bartzela et al., 2007). It shouldbe noted that the use of less stiff wires, like superelasticNiTi wires, in the initial stages of treatment is suggested incases where the existing crowding is relatively symmetric.Otherwise, there is a risk that alignment of the teeth willat the same time lead to loss of dental arch shape (Proffitet al., 2007).Kusy and Stevens (1987) mention that a three stranded0.015ãã stainless steel wire has a wider range of actionthan conventional NiTi and beta-titanium wires of thesame or larger dimensions. The same authors state thatmultistranded wires can be quite effectively compared toNiTi wires and are a possible good alternative to moreexpensive wires for the initial alignment (Quintao et al.,2009). Clinical studies comparing superelastic NiTi wires,conventional NiTi wires and multistranded stainless steelwires did not find any significant difference regarding theability and speed of initial alignment and leveling of teeth(West et al., 1995; Evans et al., 1998). Furthermore, twosystematic reviews on alignment efficiency and pain trig-gering comparing several types of single strand NiTi wiresand stainless steel wires did not reveal any significant dif-ferences (Riley and Bean, 2009; Wang et al., 2010).Intermediate stages of treatment often demand properwire bending and bonding of various biomechanical acces-

ÓÂÙ·È ˆ˜ ÌÂÁ·Ï‡ÙÂÚ· Û‡ÚÌ·Ù· ÙÂÙÚ¿ÁˆÓ˘ ›Ù ÔÚıÔ-ÁÒÓÈ·˜ ‰È·ÙÔÌ‹˜ ÂÌÊ·Ó›˙ÔÓÙ·È ÈÔ Â˘·ı‹ Û ۯ¤ÛË ÌÂÙ· ÌÈÎÚfiÙÂÚ˘ ‰È·ÙÔÌ‹˜ (Bourauel Î·È Û˘Ó., 2008).∞ÚÎÂÙ¤˜ ÎÏÈÓÈΤ˜ ÌÂϤÙ˜ ¤¯Ô˘Ó ‰Â›ÍÂÈ ˆ˜ Û ÔÏϤ˜ÂÚÈÙÒÛÂȘ Ù· ˘ÂÚÂÏ·ÛÙÈο Û‡ÚÌ·Ù· ‰ÂÓ Â›Ó·È Èηӿ Ó·ÂΉËÏÒÛÔ˘Ó ÙȘ ˘ÂÚÂÏ·ÛÙÈΤ˜ ÙÔ˘˜ ȉÈfiÙËÙ˜ in vivo ηȤÙÛÈ ‰ÂÓ ÂÌÊ·Ó›˙Ô˘Ó ÛËÌ·ÓÙÈο ÏÂÔÓÂÎÙ‹Ì·Ù· ¤Ó·ÓÙÈÙˆÓ Û˘Ì‚·ÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ NiTi (Meling Î·È Odegaard,1998a,b; Brantley, 2001).

¶¶ÔÔÏχ‡ÎÎÏψ̂ÓÓ·· ÛÛ‡‡ÚÚÌÌ··ÙÙ··∆· ÔχÎψӷ Û‡ÚÌ·Ù· ηٷÛ΢¿˙ÔÓÙ·È ·fi ÔÈΛÏÔ·ÚÈıÌfi ÏÂÙÒÓ ÎÏÒÓˆÓ Û˘ÚÌ¿ÙˆÓ ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚·Ô˘ ›Ù ÙÔÔıÂÙÔ‡ÓÙ·È ÔÌÔ·ÍÔÓÈο ›Ù ϤÎÔÓÙ·È ÌÂÙ·-͇ ÙÔ˘˜ Û ÔÈΛϘ ‰È·ÌÔÚÊÒÛÂȘ. ∏ ·Î·Ì„›· ÂÓfi˜ ÙÚ›-ÎψÓÔ˘ Û‡ÚÌ·ÙÔ˜ 0,0175 ÈÓÙÛÒÓ Â›Ó·È Û˘ÁÎÚ›ÛÈÌË Ì·˘Ù‹Ó ÂÓfi˜ ÌÔÓfiÎψÓÔ˘ Û‡ÚÌ·ÙÔ˜ ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚·‰È·ÙÔÌ‹˜ 0,010 ÈÓÙÛÒÓ, ÂÓÒ ÙÔ ÙÚ›ÎψÓÔ Û‡ÚÌ· ¤¯ÂÈ25% ÌÂÁ·Ï‡ÙÂÚË ·ÓÙÔ¯‹. ∂›Û˘, ¤Ó· ÙÚ›ÎψÓÔ Û‡ÚÌ·0,0175 ÈÓÙÛÒÓ ¤¯ÂÈ ·ÚfiÌÔÈ· ·Î·Ì„›· Ì ¤Ó· Û‡ÚÌ·ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘ ‰È·ÙÔÌ‹˜ 0,016 ÈÓÙÛÒÓ ·Ó Î·È ÙÔÛ‡ÚÌ· ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘ Âȉ¤¯ÂÙ·È 50% ÌÂÁ·Ï‡ÙÂÚËÂÓÂÚÁÔÔ›ËÛË ·fi ÙÔ ÔχÎψÓÔ. ∞ÎfiÌË, ÙÔ ÙÚ›ÎψÓÔÛ‡ÚÌ· ¤¯ÂÈ 50% ÏÈÁfiÙÂÚË ·Î·Ì„›· ·fi Û‡ÚÌ· ‚-ÙÈÙ·Ó›-Ô˘ ‰È·ÙÔÌ‹˜ 0,016 ÈÓÙÛÒÓ (Kusy Î·È Dilley, 1984). ∏ ÂÏ·-ÛÙÈ΋ Û˘ÌÂÚÈÊÔÚ¿ ÙˆÓ ÏÂÁÌ¤ÓˆÓ ÔχÎÏˆÓˆÓ Û˘Ú-Ì¿ÙˆÓ ÌÔÈ¿˙ÂÈ ÂÚÈÛÛfiÙÂÚÔ Ì ÙË Û˘ÌÂÚÈÊÔÚ¿ ÂÓfi˜ÌfiÓÔ ÎÏÒÓÔ˘ Î·È fi¯È ÂÓfi˜ Û˘ÓfiÏÔ˘ (Rucker Î·È Kusy,2002a,b,d). ∆· ÔχÎψӷ Û‡ÚÌ·Ù·, fiˆ˜ Î·È Ù· Û‡Ú-Ì·Ù· ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘, ¤¯Ô˘Ó ‡ÚÔ˜ ÂÓÂÚÁÔÔ›ËÛ˘ ÙÔÔÔ›Ô Â›Ó·È Û¯ÂÙÈο ·ÓÂÍ¿ÚÙËÙÔ ·fi ÙÔ Ì¤ÁÂıÔ˜ ÙÔ˘ Û‡Ú-Ì·ÙÔ˜, Û ·ÓÙ›ıÂÛË Ì ٷ ÌÔÓfiÎψӷ Û‡ÚÌ·Ù· ·fi ·ÓÔ-Í›‰ˆÙÔ ¯¿Ï˘‚· (Ingram Î·È Û˘Ó., 1986; Kusy Î·È Dilley,1984; Kusy, 1981).√È Taneja Î·È Û˘Ó. (2003), ÌÂÙ¿ ·fi ÂÚÁ·ÛÙËÚȷ΋ ÌÂϤ-ÙË ‰È·ÊfiÚˆÓ ÔχÎÏˆÓˆÓ Û˘ÚÌ¿ÙˆÓ ·ÓÔÍ›‰ˆÙÔ˘¯¿Ï˘‚·, η٤ÏËÍ·Ó ÛÙÔ Û˘Ì¤Ú·ÛÌ· ˆ˜ Ë ‰È¿Ù·ÍË, ˉȷÙÔÌ‹ Î·È Ô ·ÚÈıÌfi˜ ÙˆÓ ÎÏÒÓˆÓ, ·ÚfiÏÔ Ô˘ ıˆ-ÚËÙÈο ı· ¤Ú ӷ ÂËÚ¿˙Ô˘Ó ÛËÌ·ÓÙÈο ÙÔ Â‡ÚÔ˜ÙˆÓ ‰˘Ó¿ÌÂˆÓ Ô˘ ·ÛÎÔ‡ÓÙ·È Û ‰Â‰Ô̤ÓË ·Ú·ÌfiÚ-ʈÛË (Rucker Î·È Kusy, 2002d), ·˘Ùfi Ú·ÎÙÈο Û˘Ì‚·›-ÓÂÈ ÌfiÓÔ Û ·Ú·ÌÔÚÊÒÛÂȘ ÌÂÁ·Ï‡ÙÂÚ˜ ÙˆÓ 2 ¯ÈÏ..∞ÎfiÌË, ÔÈ ›‰ÈÔÈ ÂÚ¢ÓËÙ¤˜ ·Ú·Ù‹ÚËÛ·Ó ˆ˜ Ù· Û‡ÚÌ·Ù·Ì ÂÚÈÏÂÁ̤ÓÔ˘˜ ÎÏÒÓÔ˘˜ ·ÛÎÔ‡Ó ÂÓÙÔÓfiÙÂÚ˜ ‰˘Ó¿-ÌÂȘ ·fi Ù· ÔÌÔ·ÍÔÓÈο.√È ‹È˜ ‰˘Ó¿ÌÂȘ Ô˘ ·Ó·Ù‡ÛÛÔ˘Ó Ù· ÔχÎψӷۇÚÌ·Ù·, Ë ÌÈÎÚ‹ ·Î·Ì„›· Î·È ÙÔ ÌÂÁ¿ÏÔ Â‡ÚÔ˜ ÂÓÂÚÁÔ-Ô›ËÛ˘ ·ÔÙÂÏÔ‡Ó Û˘ÁÎÚ›ÛÈÌ· ¯·Ú·ÎÙËÚÈÛÙÈο Ì ·˘Ù¿ÙˆÓ ·ÎÚÈ‚fiÙÂÚˆÓ ÎÚ·Ì¿ÙˆÓ ÙÈÙ·Ó›Ô˘ (Wilkinson ηÈÛ˘Ó., 2002; Rucker Î·È Kusy, 2002a) Î·È ›Ûˆ˜ ·ÔÙÂÏÔ‡Ó

π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires HELLENIC ORTHODONTIC REVIEW

58 HELLENIC ORTHODONTIC REVIEW 2011 ñ VOLUME 14 ñ ISSUE 1

sories. Beta- titanium wires, despite their high cost, arecharacterized by very good forming behavior which, inaddition to their weldability without the need of a solder,makes them wires of choice whenever a construction of acomplex configuration is needed. Furthermore, they exerta wider range of activation and lower forces than stainlesssteel or Co-Cr wires (Kapila Î·È Sachdeva, 1989; Kusy,1997; Johnson, 2003). In cases where no wire bending isrequired NiTi wires of large cross section can be inserted(Kusy, 1997). Whenever sliding is desirable low frictionhelps the movement. In this case smaller round stainlesssteel wires are considered more appropriate (Kapila ηÈSachdeva, 1989; Kusy, 1997). At this point it should be noted that the resistance in themovement of a bracket along the wire during treatmentonly partly is a result of friction (Burrow, 2009). Laborato-ry studies show that the binding of the wire that happensshortly after the onset of tooth movement plays an impor-tant role (Thorstenson and Kusy, 2002; Hamdan and Rock,2008), and the permanent deformation caused by thenotching of the wire, that temporarily stops the move-ment, is also important (Articolo Î·È Û˘Ó., 2000; Burrow,2009). As a result, the resistance to tooth movement is nota simple phenomenon that can be easily simulated andcontrolled on laboratory tests of static or kinetic friction.On the contrary this is a multifactorial phenomenon ofbinding and release that is difficult to be successfully sim-ulated in vitro in order to be sufficiently investigated(Swartz, 2007; Burrow, 2009). As a result, all studies thatshow stainless steel wires to be superior to all other wiresespecially Ti-alloy wires, as far as friction is concerned, areprobably of small clinical importance (Peterson Î·È Û˘Ó.,1982; Kusy Î·È Whitley, 1990; Kusy Î·È Whitley, 1989;Kapila Î·È Û˘Ó., 1990; Cash Î·È Û˘Ó., 2004; Krishnan ηÈKumar, 2004a).In the final stages of treatment, where smaller move-ments are needed, the greater stability and torque con-trol, formability and stiffness of stainless steel (or Cr-Co)wires make them wires of choice (Kapila and Sachdeva,1989; Kusy, 1997). In cases where the corrections thatmust be done are larger, it is better to use beta-titaniumwires in order to have greater range of activation and toavoid putting excessive forces on the teeth (Johnson,2003). The low stiffness of NiTi wires makes them unsuit-able for the final stages of treatment.Sometimes, rectangular multistranded stainless steelwires are used for the final settling of dental archesbecause they allow small dental movements while keep-ing the final position of teeth.Furthermore, multistranded wires are frequently used forretention purposes after the orthodontic treatment,where usually round wires (0.0215ãã) bonded on the frontteeth are used (Zachrisson, 2007). It is suggested that thewire should be submitted to some kind of thermal work-

Ì›· ÔÈÎÔÓÔÌÈ΋ ÂÓ·ÏÏ·ÎÙÈ΋ χÛË (Kusy Î·È Dilley,1984; Kusy Î·È Stevens, 1987). øÛÙfiÛÔ, Ù· ÔχÎψӷۇÚÌ·Ù· ‰ÂÓ ·ÛÎÔ‡Ó ¿ÓÙÔÙ ¯·ÌËϤ˜ Î·È Û¯ÂÙÈο ÛÙ·-ıÂÚ¤˜ ‰˘Ó¿ÌÂȘ ηٿ ÙËÓ ·ÔÊfiÚÙÈÛË ÙÔ˘˜, ȉȷ›ÙÂÚ·ÌÂÙ¿ ·fi ÛËÌ·ÓÙÈ΋ ·Ú·ÌfiÚʈÛË (Taneja Î·È Û˘Ó.,2003). ™¯ÂÙÈο Ì ÙËÓ ÙÚÈ‚‹, Ù· ÔχÎψӷ Û‡ÚÌ·Ù··ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· ·Ó·Ù‡ÛÛÔ˘Ó ¯·ÌËÏfiÙÂÚË ÙÚÈ‚‹ÛÙË ‰ÈÂÈÊ¿ÓÂÈ· Û‡ÚÌ·ÙÔ˜-·ÁÎ˘Ï›Ô˘ ·fi Ù· Û‡ÚÌ·Ù·NiTi Î·È ÂÚ›Ô˘ ηٿ 1/3 ˘„ËÏfiÙÂÚË ·fi Ù· ÌÔÓfiÎψ-Ó· Û‡ÚÌ·Ù· ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· (Rucker Î·È Kusy,2002c).

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√È ÎÏÈÓÈΤ˜ ÂÊ·ÚÌÔÁ¤˜ ÙˆÓ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓÌÔÚÔ‡Ó Ó· ‚ÂÏÙÈÛÙÔÔÈËıÔ‡Ó Ì ÚÔÛÂÎÙÈ΋ ÂÈÏÔÁ‹ÙÔ˘ ηٿÏÏËÏÔ˘ Ù‡Ô˘ Î·È ÌÂÁ¤ıÔ˘˜ Û‡ÚÌ·ÙÔ˜ Ô˘ Èη-ÓÔÔÈ› ÙȘ ··ÈÙ‹ÛÂȘ Ù˘ ÂοÛÙÔÙ ÎÏÈÓÈ΋˜ ÂÚ›ÙˆÛ˘.∏ ÂÈÏÔÁ‹ Ù˘ ÛÂÈÚ¿˜ ÙˆÓ Û˘ÚÌ¿ÙˆÓ Î·Ù¿ ÙË ‰È¿ÚÎÂÈ·Ù˘ ıÂڷ›·˜ ÌÔÚ› Ó· ÌÂÙ·‚¿ÏÏÂÙ·È ·Ó¿ÏÔÁ· Ì Ù˯ÚËÛÈÌÔÔÈÔ‡ÌÂÓË Ù¯ÓÈ΋ (.¯. ¯Ú‹ÛË ÙÌËÌ·ÙÈÎÒÓÙfiÍˆÓ ‹ straight-wire Ù¯ÓÈ΋). øÛÙfiÛÔ, ·Ó Ô ÔÚıÔ‰Ô-ÓÙÈÎfi˜ ÁÓˆÚ›˙ÂÈ ÙȘ ‚·ÛÈΤ˜ ȉÈfiÙËÙ˜ Î·È ÙËÓ ÂÌ‚ÈÔÌ˯·-ÓÈ΋ Û˘ÌÂÚÈÊÔÚ¿ ÙˆÓ Û˘ÚÌ¿ÙˆÓ, ÌÔÚ› Ó· ÂÈϤÁÂÈ ÙÔηٿÏÏËÏÔ ˘ÏÈÎfi, Û¯‹Ì· Î·È Ì¤ÁÂıÔ˜ ÁÈ· οı ÂÚ›Ùˆ-ÛË ‹ ·ÎfiÌË Î·È Ó· Ú·ÁÌ·ÙÔÔÈ› Û˘Ó‰˘·ÛÌÔ‡˜ وӉȷÊfiÚˆÓ Ù¯ÓÈÎÒÓ Ì ÛÙfi¯Ô ÙËÓ ÔÈÔÙÈÎfiÙÂÚË ·ÚÔ¯‹˘ËÚÂÛÈÒÓ ÚÔ˜ ÙÔÓ ·ÛıÂÓ‹. ™˘Ó‹ıˆ˜, ÛÙ· ·Ú¯Èο ÛÙ¿-‰È· Ù˘ ÔÚıÔ‰ÔÓÙÈ΋˜ ıÂڷ›·˜ ¯ÚËÛÈÌÔÔÈÔ‡ÓÙ·È ˘Â-ÚÂÏ·ÛÙÈο Û‡ÚÌ·Ù· NiTi, ÂÓÒ ÛÙ· ÌÂÛ·›· Î·È ÙÂÏÈο ÛÙ¿-‰È· Û‡ÚÌ·Ù· ‚-ÙÈÙ·Ó›Ô˘ Î·È ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· (KeimÎ·È Û˘Ó., 2002). ∆Ô ˘„ËÏfi ̤ÙÚÔ ÂÏ·ÛÙÈÎfiÙËÙ·˜ ÙˆÓ Û˘Ú-Ì¿ÙˆÓ ÎÔ‚·ÏÙ›Ô˘-¯ÚˆÌ›Ô˘ Î·È ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚·˘Ô‰ËÏÒÓÂÈ ˆ˜ Ù· Û‡ÚÌ·Ù· ·˘Ù¿ ·ÛÎÔ‡Ó 2 ÊÔÚ¤˜ÌÂÁ·Ï‡ÙÂÚË ‰‡Ó·ÌË ·fi Ù· Û‡ÚÌ·Ù· ‚-ÙÈÙ·Ó›Ô˘ Î·È 4ÊÔÚ¤˜ ÌÂÁ·Ï‡ÙÂÚË ‰‡Ó·ÌË ·fi Ù· Û˘Ì‚·ÙÈο Û‡ÚÌ·Ù·ÓÈÎÂÏ›Ô˘ ÙÈÙ·Ó›Ô˘ fiÙ·Ó ˘Ô‚ÏËıÔ‡Ó ÛÙÔ ›‰ÈÔ Ì¤ÁÂıÔ˜ÂÓÂÚÁÔÔ›ËÛ˘ (Drake Î·È Û˘Ó., 1982).ªÂϤÙ˜ ÙˆÓ ÂÏ·ÛÙÈÎÒÓ È‰ÈÔÙ‹ÙˆÓ ÙˆÓ Û˘ÚÌ¿ÙˆÓ ·Ó·-ʤÚÔ˘Ó ˆ˜ Ë Û¯¤ÛË Ô˘ ηıÔÚ›˙ÂÈ ÙË ÏÂÈÙÔ˘ÚÁ›· ÙˆÓÛ˘ÚÌ¿ÙˆÓ Â›Ó·È Ë ÂÍ‹˜: strength = stiffness x range ‹(‰‡Ó·ÌË = ·Î·Ì„›· x ‡ÚÔ˜) (Kusy Î·È Greenberg,1981). °È· Ù· ÁÚ·ÌÌÈÎÒ˜ ÂÏ·ÛÙÈο Û‡ÚÌ·Ù· Ù· ¯·Ú·ÎÙË-ÚÈÛÙÈο ·˘Ù¿ ÔÚ›ÛÙËÎ·Ó ˆ˜ (1) strength: Ë Ì¤ÁÈÛÙË ‰‡Ó·-ÌË Ô˘ ÌÔÚ› Ó· ÚÔηϤÛÂÈ ÂÏ·ÛÙÈ΋ ·Ú·ÌfiÚʈÛËÛÙÔ Û‡ÚÌ·, (2) stiffness: Ë ·Ó·ÏÔÁ›· strength ÚÔ˜range, Ô˘ ÈÛÔ‡Ù·È Ì ÙË ‰‡Ó·ÌË ·Ó¿ ÌÔÓ¿‰· ÂÓÂÚÁÔ-Ô›ËÛ˘ Î·È (3) range: Ë Ì¤ÁÈÛÙË ·fiÛÙ·ÛË Ô˘ ÌÔÚ›¤Ó· Û‡ÚÌ· Ó· ÂÓÂÚÁÔÔÈËı› ÂÏ·ÛÙÈο. ªÂ ÂÍ·›ÚÂÛË ÔÚÈ-Ṳ̂ÓÔ˘˜ Ù‡Ô˘˜ Û˘ÚÌ¿ÙˆÓ NiTi, ÁÈ· Ù· ˘fiÏÔÈ· Û‡Ú-

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H 2011 ñ TOMO™ 14 ñ TEYXO™ 1 59

Ì·Ù· Ë Û¯¤ÛË ‰‡Ó·Ì˘ Î·È ÂÏ·ÛÙÈ΋˜ ·Ú·ÌfiÚʈÛË˜Â›Ó·È ÁÚ·ÌÌÈ΋ (Zufall Î·È Kusy, 2000a). ¶Ú¤ÂÈ Ó· ÙÔÓÈ-ÛÙ› ˆ˜ Î·È ÔÈ ÙÚÂȘ ‚·ÛÈΤ˜ ÂÏ·ÛÙÈΤ˜ ȉÈfiÙËÙ˜ ÙˆÓÛ˘ÚÌ¿ÙˆÓ (strength, stiffness, range) ÌÂÙ·‚¿ÏÏÔÓÙ·ÈÔÛÔÙÈο ·fi ÌÂÙ·‚ÔϤ˜ ÛÙË ÁˆÌÂÙÚ›· (Û¯‹Ì·), ÙÔ̤ÁÂıÔ˜ Î·È ÙÔ Ì‹ÎÔ˜ ÙÔ˘ Û‡ÚÌ·ÙÔ˜. °È· ÙËÓ ÏÂÈÔ„ËÊ›·ÙˆÓ Û˘Ì‚·ÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ Ë ÂÏ·ÛÙÈÎfiÙËÙ· Î·È ÙÔ Â‡ÚÔ˜ÂÚÁ·Û›·˜ ÙÔ˘˜ ÌÂÈÒÓÂÙ·È Ì ÙËÓ ·‡ÍËÛË ÙÔ˘ ÌÂÁ¤ıÔ˘˜,ÂÓÒ Ë ·Î·Ì„›· ·˘Í¿ÓÂÙ·È. ∫¿ÙÈ Ù¤ÙÔÈÔ ‰ÂÓ Ê·›ÓÂÙ·È Ó·ÈÛ¯‡ÂÈ ¿ÓÙÔÙ ÁÈ· Ù· ÔχÎψӷ Û‡ÚÌ·Ù· ·ÓÔÍ›‰ˆÙÔ˘¯¿Ï˘‚· Î·È È‰È·›ÙÂÚ· ÁÈ· Ù· ˘ÂÚÂÏ·ÛÙÈο Û‡ÚÌ·Ù· NiTi(Ingram Î·È Û˘Ó., 1986). °È· Ù· ˘fiÏÔÈ· Û‡ÚÌ·Ù·, ÔÈÌÂÙ·‚ÔϤ˜ Ô˘ Û¯ÂÙ›˙ÔÓÙ·È Ì ÙÔ Ì¤ÁÂıÔ˜ Î·È ÙÔ Û¯‹Ì·Û˘Ì‚·›ÓÔ˘Ó Î·Ù¿ ÙÔ ›‰ÈÔ ÔÛÔÛÙfi ·ÓÂÍ¿ÚÙËÙ· ·fi ÙÔ˘ÏÈÎfi ηٷÛ΢‹˜. °È· ·Ú¿‰ÂÈÁÌ·, ÌÂÈÒÓÔÓÙ·˜ ÙË ‰È¿-ÌÂÙÚÔ ÂÓfi˜ Û‡ÚÌ·ÙÔ˜ ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· ηٿ 50%,ı· ÌÂȈı› Î·È Ë ·Î·Ì„›· ÙÔ˘ ÛÂ Û˘ÁÎÂÎÚÈ̤ÓÔ ÔÛÔÛÙfiÙ˘ ÚÔ¸¿Ú¯Ô˘Û·˜. ∂ÈÚfiÛıÂÙ·, ÌÂÈÒÓÔÓÙ·˜ ÙË ‰È¿ÌÂ-ÙÚÔ ÂÓfi˜ Û‡ÚÌ·ÙÔ˜ ‚-ÙÈÙ·Ó›Ô˘ ηٿ 50%, ı· ÌÂȈı› ˷η̄›· ÙÔ˘ ηٿ ÙÔ ›‰ÈÔ ·ÎÚÈ‚Ò˜ ÔÛÔÛÙfi Ù˘ ÚÔ¸-¿Ú¯Ô˘Û·˜ (Proffit Î·È Û˘Ó., 2007). ∞ÎfiÌË, fiÙ·Ó ÙÔÌ‹ÎÔ˜ ÂÓfi˜ Û‡ÚÌ·ÙÔ˜ ÌÂٷ͇ ‰‡Ô ÛËÌ›ˆÓ ÚfiÛ‰ÂÛ˘·˘Í¿ÓÂÙ·È, Ë ·Î·Ì„›· ÙÔ˘ ÌÂÈÒÓÂÙ·È ·Ó¿ÏÔÁ·, ·ÏÏ¿ ËÂÏ·ÛÙÈÎfiÙËÙ· Î·È ÙÔ Â‡ÚÔ˜ ÂÚÁ·Û›·˜ ÙÔ˘ ·˘Í¿ÓÔÓÙ·ÈÂÎıÂÙÈο. ∆¤ÏÔ˜, fiÙ·Ó ¤Ó· Û‡ÚÌ· ÚÔÛ‰¤ÓÂÙ·È ¯·Ï·Ú¿ÛÙ· ·Á·ÏÈ· Î·È ¤¯ÂÈ ÙË ‰˘Ó·ÙfiÙËÙ· ‰ÈÔÏ›ÛıËÛ˘, Ë ÂÏ·-ÛÙÈÎfiÙËÙ· ÙÔ˘ ·˘Í¿ÓÂÙ·È ÛËÌ·ÓÙÈο (Adams Î·È Û˘Ó.,1987). ¶Ú¤ÂÈ Ó· ÛËÌÂȈı› ˆ˜, fiÙ·Ó ÔÈ ÁˆÓ›Â˜ ÙˆÓ ÙÂÙÚ¿Áˆ-ÓˆÓ ‹ ÔÚıÔÁÒÓÈˆÓ Û˘ÚÌ¿ÙˆÓ Â›Ó·È Û¯ÂÙÈο ·ÔÛÙÚÔÁ-Á˘ÏÂ̤Ó˜, ÌÂÈÒÓÂÙ·È ÛËÌ·ÓÙÈο ÙÔ ÏÂÔÓ¤ÎÙËÌ· ÙÔ˘ÂϤÁ¯Ô˘ Ù˘ ÛÙÚ¤„˘ (torque) ÂÓÒ ÌÂÈÒÓÂÙ·È Î·È Ë ·Î·Ì-„›· ÙÔ˘˜. O ¤ÏÂÁ¯Ô˜ Ù˘ ÛÙÚ¤„˘ (torque) ÂÍ·ÚÙ¿Ù·È ·fiÔÏÏÔ‡˜ ·Ú¿ÁÔÓÙ˜ Ô˘ ¤¯Ô˘Ó Û¯¤ÛË Ì ÙÔ ·Á·ÏÈÔÎ·È ÙË Û¯Â‰›·Û‹ ÙÔ˘, ÙÔÓ Ù‡Ô ÚfiÛ‰ÂÛ˘, ÙÔÓ ÂχıÂÚÔ¯ÒÚÔ ÌÂٷ͇ Û‡ÚÌ·ÙÔ˜-˘Ô‰Ô¯‹˜ ·ÁÎ˘Ï›Ô˘ Î·È ÙÔÛ‡ÚÌ·. ∆Ô ˘ÏÈÎfi ηٷÛ΢‹˜, Ë ‰È·ÙÔÌ‹ Î·È Ô ‚·ıÌfi˜·ÔÛÙÚÔÁÁ‡Ï¢Û˘ ÙˆÓ ÁˆÓÈÒÓ ÙÔ˘ Û‡ÚÌ·ÙÔ˜ (edgebevel) Ê·›ÓÂÙ·È ˆ˜ ·›˙Ô˘Ó ÛËÌ·ÓÙÈÎfi ÚfiÏÔ (SebancÎ·È Û˘Ó., 1984; Gioka Î·È Eliades 2004; Morina Î·È Û˘Ó.,2008). ™Â ÌÈÎÚ¤˜ ÂÓÂÚÁÔÔÈ‹ÛÂȘ (<12Æ), ‰ÂÓ ÂÓÙÔ›ÛÙËΉȷÊÔÚ¿ ÛÙËÓ ¤ÎÊÚ·ÛË Ù˘ ÛÙÚ¤„˘ (torque) ÌÂÙ·Í‡Û˘ÚÌ¿ÙˆÓ ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚·, ∆ª∞ Î·È Cu-Ni-Ti, ÂÓÒÛ ÌÂÁ·Ï‡ÙÂÚ˜ ÁˆÓ›Â˜ (>24Æ) Ù· Û‡ÚÌ·Ù· ·ÓÔÍ›‰ˆÙÔ˘¯¿Ï˘‚· ·Ô‰›‰Ô˘Ó ‰˘Ó¿ÌÂȘ 1,5-2 ÊÔÚ¤˜ ÌÂÁ·Ï‡ÙÂÚ˜·fi Ù· Û‡ÚÌ·Ù· ∆ª∞ Î·È 2,5-3 ÊÔÚ¤˜ ÌÂÁ·Ï‡ÙÂÚ˜ ·fiÙ· Cu-Ni-Ti (Archambault Î·È Û˘Ó., 2010). µÚ¤ıËΠˆ˜Ë ÂΉ‹ÏˆÛË ˘ÂÚÂÏ·ÛÙÈÎfiÙËÙ·˜ Û ıÂÚÌÔÎÚ·Û›· ÛÙfiÌ·-ÙÔ˜ ηٿ ÙË ÛÙÚ¤„Ë Û˘ÚÌ¿ÙˆÓ ¡i-Ti ÂÌÊ·Ó›˙ÂÙ·È ÂÚ›Ô˘ÛÙȘ 20 ÌÔ›Ú˜, ÂÓÒ ·Ú¿ÏÏËÏ· ·Ú·ÙËÚÔ‡ÓÙ·È ÌÂÁ¿Ï˜

ing before its final fitting on the teeth in order to removeany residual stresses.

AADDVVAANNCCEESS –– AAEESSTTHHEETTIICC WWIIRREESS

Up until now, an aesthetic wire accompanied with therequired mechanical properties making it essentially use-ful for progress in orthodontics has not been found. Thetwo types of aesthetic wires available are metal-coatedand fiber-reinforced wires. Of these two, those availablefor clinical use are the metal-coated ones, since fiber-rein-forced ones are still in experimental stage. The materialsused for coating are synthetic fluoride resins, Teflon, orepoxy polytetrafluoroethylene resins (Elayyan et al., 2008;Elayyan et al., 2010). The so-called "white wires" areprone to chewing forces or the enzymatic activity of theoral cavity within three weeks of use in vivo (Kusy, 1997).Color instability of these wires and exposure of the under-lying metal is also often reported (Lim et al., 1994). It hasbeen found that 25% of coating is lost in 33 days intra-orally, therefore, the wire becomes aesthetically degraded(Elayyan et al., 2008). The coating seems to initially lowerbracket-wire friction (Husmann et al., 2002), however, sur-face roughness values soon increase in clinical use(Elayyan et al., 2008). Coated wires deliver lower forceswhen loaded and unloaded compared to non-coatedwires of the same nominal diameter (Elayyan et al., 2010).This finding, even though expected (due to coating thick-ness, a slightly lower section wire is used), should betaken into account since a large number of orthodonticsuse wire diameter as their guide in certain clinical cases(Elayyan et al., 2010). The use of synthetic materials including matrixes rein-forced with glass or others fibers is much promising (Zufalland Kusy, 2000b; Goldberg and Burstone, 1992). The stiff-ness of these wires may be determined when manufac-tured without changing the wire’s dimensions, by chang-ing fiber geometry and/or the ratios of fiber and matrixmaterials and properly polymerising them (Imai et al.,1998; Zufall and Kusy, 2000b). This makes it possible tomanufacture even rectangular aesthetic wires (Fallis andKusy., 2000). A recent study of a 3-point bending test onfiber-reinforced and stainless steel wires led to encourag-ing results (Cacciafesta et al., 2008). Since synthetic materials replace metal alloys in aeronau-tics, something similar is expected to occur to a certainextent in orthodontics in the near future (Kusy, 1997).Recently, in the wider scientific field of materials, polymerswith shape memory have been produced and used in avariety of biomedical applications (Lendlein et al., 2005).These materials may be a viable alternative to orthodon-tic wires currently used in the future (Eliades, 2007). Anovel (experimental) type of aesthetic materials for ortho-dontic use referred to as self-reinforced polymer compos-

π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires HELLENIC ORTHODONTIC REVIEW

60 HELLENIC ORTHODONTIC REVIEW 2011 ñ VOLUME 14 ñ ISSUE 1

·ÔÎÏ›ÛÂȘ ·Ó¿ÏÔÁ· Ì ÙÔÓ Î·Ù·Û΢·ÛÙ‹. ∞˘Ùfi, ÛÂÛ˘Ó‰˘·ÛÌfi Ì ÙËÓ ÂÏ¢ıÂÚ›· ΛÓËÛ˘ ÙÔ˘ Û‡ÚÌ·ÙÔ˜ÂÓÙfi˜ Ù˘ ˘Ô‰Ô¯‹˜ ÙÔ˘ ·ÁÎ˘Ï›Ô˘ ηıÈÛÙÔ‡Ó ÙËÓ ÔÚÈÔ-ı¤ÙËÛË Ù˘ Û˘Û¯¤ÙÈÛ˘ Ù˘ ‰È·ÙÔÌ‹˜ ÙˆÓ Û˘ÚÌ¿ÙˆÓ ¡i-TiÌ ÙËÓ Ú·ÁÌ·ÙÈ΋ ÛÙÚÂÙÈ΋ ‰‡Ó·ÌË Ô˘ ·Ô‰›‰Ô˘Óȉȷ›ÙÂÚ· ‰‡ÛÎÔÏË ÁÈ· ÙÔÓ ÎÏÈÓÈÎfi (Partowi Î·È Û˘Ó.,2010).™‡Ìʈӷ Ì ÙÔÓ Burstone (1981), Ë ÂÈı˘ÌËÙ‹ ÛÙ·‰È·Î‹·‡ÍËÛË Ù˘ ·Î·Ì„›·˜ ÙˆÓ Û˘ÚÌ¿ÙˆÓ ·Ú¿ÏÏËÏ· Ì ÙËÓÚfiÔ‰Ô Ù˘ ıÂڷ›·˜ ÌÔÚ› Ó· ÂÈÙ¢¯ı› fi¯È ÌfiÓÔ ÌÂηٿÏÏËÏË ‰È·ÌfiÚʈÛË ÙˆÓ Û˘ÚÌ¿ÙˆÓ ‹ ·‡ÍËÛË ÙÔ˘ÌÂÁ¤ıÔ˘˜ ÙÔ˘˜, ·ÏÏ¿ Î·È Ì ÙËÓ ÂÈÏÔÁ‹ Û˘ÚÌ¿ÙˆÓ ÌÂÛÙ·‰È·Î¿ ·˘Í·ÓfiÌÂÓÔ Ì¤ÙÚÔ ÂÏ·ÛÙÈÎfiÙËÙ·˜ (Variable-modulus orthodontics). ¢È¿ÊÔÚ˜ ÂÚÁ·ÛÙËÚȷΤ˜ ÌÂϤ-Ù˜ ¤¯Ô˘Ó ‰Â›ÍÂÈ ˆ˜ Ë ·ÛÎÔ‡ÌÂÓË ‰‡Ó·ÌË Î·È Ë ·Î·Ì„›·ÙÔ˘ Û‡ÚÌ·ÙÔ˜ ÌÂÙ·‚¿ÏÏÔÓÙ·È ·Ó¿ÏÔÁ· (Rucker Î·È Kusy,2002a, b; Garrec Î·È Û˘Ó., 2005). ∏ Û¯¤ÛË Ù˘ ·Î·Ì„›·˜ÙˆÓ Û˘ÚÌ¿ÙˆÓ ¯ÚˆÌ›Ô˘-ÎÔ‚·ÏÙ›Ô˘, ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘-‚·, ‚-ÙÈÙ·Ó›Ô˘ Î·È ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘ Â›Ó·È ·ÓÙ›ÛÙÔȯ·1,2:1:0,42:0,26. ∏ ·Î·Ì„›· ÙˆÓ ÔχÎÏˆÓˆÓ Û˘ÚÌ¿ÙˆÓÎ˘Ì·›ÓÂÙ·È ÌÂٷ͇ 1/25-1/5 Ù˘ ·Î·Ì„›·˜ ÂÓfi˜ ÌÔÓfiÎψ-ÓÔ˘ Û‡ÚÌ·ÙÔ˜ ·fi ·ÓÔÍ›‰ˆÙÔ ¯¿Ï˘‚· (Burstone,1981). ∞˘Ù‹ Ë Ù¯ÓÈ΋ ‰›ÓÂÈ ÛÙÔÓ ÎÏÈÓÈÎfi ÙË ‰˘Ó·ÙfiÙËÙ·¯Ú‹Û˘ ÌÂÁ¿ÏÔ˘ ÌÂÁ¤ıÔ˘˜, ·ÎfiÌË Î·È ÙÂÙÚ¿ÁˆÓˆÓ ‹ÔÚıÔÁÒÓÈˆÓ Û˘ÚÌ¿ÙˆÓ, Û ڈ˚ÌfiÙÂÚ· ÛÙ¿‰È· Ù˘ıÂڷ›·˜ ·Ú¤¯ÔÓÙ·˜ ηχÙÂÚÔ ¤ÏÂÁ¯Ô ÙˆÓ ÌÂÙ·ÎÈÓ‹ÛÂ-ˆÓ ÛÙȘ ÙÚÂȘ ‰È·ÛÙ¿ÛÂȘ ÙÔ˘ ¯ÒÚÔ˘. ∂ÈÚfiÛıÂÙ·, Û‡Ì-ʈӷ Ì ÙÔÓ Kusy (1997), Ë ‰È·Ù‹ÚËÛË Û¯ÂÙÈο ÛÙ·ıÂ-ÚÒÓ ÁˆÓÈ·ÎÒÓ Û¯¤ÛÂˆÓ Û‡ÚÌ·ÙÔ˜-˘Ô‰Ô¯‹˜ ·ÁÎ˘Ï›Ô˘ÂÈÙÚ¤ÂÈ ÙÔÓ Î·Ï‡ÙÂÚÔ ¤ÏÂÁ¯Ô ÙˆÓ ÂȤ‰ˆÓ Ù˘ ÙÚÈ‚‹˜.ŸÌˆ˜, ·ÚfiÏÔ Ô˘ Ë ÌÈÎÚ‹ ·Î·Ì„›· Î·È ÙÔ ÌÂÁ¿ÏÔ‡ÚÔ˜ ÂÚÁ·Û›·˜ ÙÔ˘ Û‡ÚÌ·ÙÔ˜ Â›Ó·È ÂÈı˘ÌËÙ¤˜ ȉÈfiÙËÙ˜ηٿ ÙËÓ ÌÂٷΛÓËÛË ‰ÔÓÙÈÒÓ, Ë ‰Ú¿ÛË ÙÔ˘ Û‡ÚÌ·ÙÔ˜ ÛÂÂÚÈÔ¯¤˜ Ô˘ ‰ÂÓ ÂÈı˘ÌÂ›Ù·È ÌÂٷΛÓËÛË, ΢ڛˆ˜ ηٿٷ ÙÂÏÈο ÛÙ¿‰È· Ù˘ ıÂڷ›·˜, ÂϤÁ¯ÂÙ·È Î·Ï‡ÙÂÚ· ÌÂÛ‡ÚÌ·Ù· Ì ÌÈÎÚfiÙÂÚÔ Â‡ÚÔ˜ ÂÚÁ·Û›·˜ Î·È ÌÂÁ·Ï‡ÙÂÚ˷η̄›· (Burstone, 1985).™Ù· ·Ú¯Èο ÛÙ¿‰È· Ù˘ ıÂڷ›·˜ ÚÔÙÈÌ¿Ù·È Ë ¯Ú‹ÛËÛ˘ÚÌ¿ÙˆÓ Ì ÌÂÁ¿ÏÔ Â‡ÚÔ˜ ÂÓÂÚÁÔÔ›ËÛ˘ Î·È ·fi‰ÔÛË‹ÈˆÓ ‰˘Ó¿ÌÂˆÓ ÁÈ· ÙËÓ ÂȤ‰ˆÛË Î·È Â˘ı˘ÁÚ¿ÌÌÈÛËÙˆÓ ‰ÔÓÙÈÒÓ (Kusy, 1997). ∆˘Èο, Ô ÎÏÈÓÈÎfi˜ ÔÚıÔ‰ÔÓÙÈ-Îfi˜ ÂÈϤÁÂÈ ¤Ó· Û‡ÚÌ· Ì ÌÈÎÚ‹ ·Î·Ì„›·, ÌÂÁ¿ÏË ÂÏ·-ÛÙÈÎfiÙËÙ· Î·È ÈηÓÔÔÈËÙÈ΋ ·ÓÙÔ¯‹ (Rucker Î·È Kusy,2002b). ∆Ô ÚÒÙÔ Û‡ÚÌ· ı· Ú¤ÂÈ Ó· ÂÈϤÁÂÙ·È ÒÛÙÂηٿ ÙËÓ ÙÔÔı¤ÙËÛË ÙÔ˘ ÛÙÔ ÛËÌ›Ô-·Á·ÏÈÔ Ì¤ÁÈÛÙ˘ÂÓÂÚÁÔÔ›ËÛ˘ Ó· ·ÛΛ ÙË Ì¤ÁÈÛÙË ‰˘Ó·Ù‹ ·Ô‰ÂÎÙ‹‰‡Ó·ÌË (Johnson, 2003). £ÂˆÚËÙÈο, Ù· ÚÒÙ· Û‡ÚÌ·Ù·ı· Ú¤ÂÈ Ó· Â›Ó·È ÛÙÚÔÁÁ˘Ï¿ ˘ÂÚÂÏ·ÛÙÈο NiTi Û‡ÚÌ·-Ù·, ÌÈÎÚ‹˜ ‰È·ÙÔÌ‹˜, ÂÓÒ ÌÂÙ¤ÂÈÙ· ÌÔÚÔ‡Ó Ó· ¯ÚËÛÈ-ÌÔÔÈËıÔ‡Ó NiTi Û‡ÚÌ·Ù· ÔÚıÔÁÒÓÈ·˜ ‰È·ÙÔÌ‹˜, Ù·

ites is also of particular interest. They are made ofpolyphenylene, which demonstrates time-dependentrelaxation. Subsequently, their potential use in clinicalpractice will require the expert orthodontist to understandthis behavior of wires (Goldberg et al., 2010).

CCOONNCCLLUUSSIIOONNSS

Currently, a large variety of alloys is used to produceorthodontic wires. Each type of wire demonstrates certainproperties, which sometimes vary significantly betweenmanufacturers. Different alloy properties combined withthe variety in sizes and geometries make the selection ofthe proper wire for a specific clinical case a highlydemanding process.Knowledge of the mechanical and physical properties ofwires, which, to some extent, determine their clinicalbehavior is required to achieve a satisfactory and pre-dictable outcome. Usually, as treatment progresses, wireswith gradually increasing stiffness are chosen. However,since the ideal wire has not yet been discovered, each wiremay be an appropriate choice or not, depending on thetreatment stage and the desired clinical outcome. Theselection and sequence of wires should neither be madeirrationally nor be determined in advance for all patients;instead, it should rely on current scientific evidence andthe clinical requirements of each case.Advances in the field of biomaterials have providedencouraging results with regard to the creation of aes-thetic wires with satisfactory properties. It seems that inthe near future these wires will be available for ortho-dontics, thus increasing the range of available options.

RReeffeerreenncceess

Adams DM, Powers JM, Asgar K. Effects of brackets and ties on stiff-ness of an arch wire. Am J Orthod Dentofacial Orthop1987;91:131-6.

Airoldi G, Riva G, Vanelli M, Filippi V, Garattini G. Oral environmenttemperature changes induced by cold/hot liquid intake. Am JOrthod Dentofacial Orthop 1997;112:58-63.

Andreasen GF, Hileman TB. An evaluation of 55-cobalt substitutedwire for orthodontics. J Am Dent Assoc 1971;82:1373-5.

Andreasen G, Hileman H, Krell D. Stiffness changes in thermody-namic nitinol with increasing temperature. Angle Orthod1985;55:120-6.

Andreasen GF, Morrow RE. Laboratory and clinical analyses of nitinolwire. Am J Orthod 1978;73:142-51.

Archambault A, Major TW, Carey JP, Heo G, Badawi H, Major PW. Acomparison of torque expression between stainless steel, titani-um molybdenum alloy, and copper nickel titanium wires inmetallic self-ligating brackets. Angle Orthod 2010;80:884-9.

Articolo LC, Kusy K, Saunders CR, Kusy RP. Influence of ceramic andstainless steel brackets on the notching of archwires during clin-ical treatment. Eur J Orthod 2000;22:409-25.

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H 2011 ñ TOMO™ 14 ñ TEYXO™ 1 61

ÔÔ›· Â›Ó·È Û¯ÂÙÈο ÈÔ ¿Î·ÌÙ·. ∆· Û‡ÚÌ·Ù· Ni-Ti·ÚÔ˘ÛÈ¿˙Ô˘Ó ·˘ÍË̤ÓË ÂÏ·ÛÙÈÎfiÙËÙ· Ô˘ ÂÈÙÚ¤ÂÈÌÂÁ¿ÏÔ Â‡ÚÔ˜ ÂÏ·ÛÙÈ΋˜ ·Ú·ÌfiÚʈÛ˘ Î·È ÂÓÂÚÁÔÔ›-ËÛ˘ (Andreasen Î·È Morrow, 1978; Drake Î·È Û˘Ó.,1982; Brantley, 2001), ÂÓÒ ÁÈ· ‰Â‰Ô̤ÓÔ ÔÛfi ÂÓÂÚÁÔ-Ô›ËÛ˘ ·ÛÎÔ‡Ó ËÈfiÙÂÚË Î·È ÂÚÈÛÛfiÙÂÚÔ ÛÙ·ıÂÚ‹‰‡Ó·ÌË ·fi fiÙÈ ·˘Ù¿ ·fi ·ÓÔÍ›‰ˆÙÔ ¯¿Ï˘‚· ‹ ÎÔ‚¿Ï-ÙÈÔ-¯ÚÒÌÈÔ. ∞ÓÙ›ıÂÙ·, Ù· Û‡ÚÌ·Ù· ·fi ·ÓÔÍ›‰ˆÙÔ ¯¿Ï˘-‚· ·Ú¿ÁÔ˘Ó ÂÓÙÔÓfiÙÂÚ˜ ‰˘Ó¿ÌÂȘ Ô˘ ·ÛÎÔ‡ÓÙ·È ÛÂÌÈÎÚfiÙÂÚ˜ ¯ÚÔÓÈΤ˜ ÂÚÈfi‰Ô˘˜ Î·È Û˘ÓÂÒ˜ ··ÈÙÔ‡ÓÛ˘¯ÓfiÙÂÚ˜ ÂÓÂÚÁÔÔÈ‹ÛÂȘ Î·È ÂÚÈÛÛfiÙÂÚ˜ ·ÏÏ·Á¤˜Û˘ÚÌ¿ÙˆÓ. ™‡Ìʈӷ Ì ÙÔ˘˜ Andreasen Î·È Morrow(1978) Ù· ÎÏÈÓÈο ÏÂÔÓÂÎÙ‹Ì·Ù· ÙˆÓ Û˘ÚÌ¿ÙˆÓ ÓÈÎÂÏ›-Ô˘-ÙÈÙ·Ó›Ô˘ ÂÚÈÏ·Ì‚¿ÓÔ˘Ó ÙȘ ÏÈÁfiÙÂÚ˜ ·ÏÏ·Á¤˜ Û˘Ú-Ì¿ÙˆÓ, ÙȘ ÌÈÎÚfiÙÂÚ˜ Û˘Ó‰ڛ˜, ÙËÓ Ù·¯‡ÙÂÚË ÂȤ‰ˆ-ÛË Î·È ‰ÈfiÚıˆÛË ÙˆÓ ÛÙÚÔÊÒÓ Î·È ÙË ÌÈÎÚfiÙÂÚË Ù·Ï·È-ˆÚ›· ÙÔ˘ ·ÛıÂÓ‹. ¶ÚÔÙ›ÓÂÙ·È ˆ˜ Ë ¯Ú‹ÛË ÔÚıÔÁÒ-ÓÈˆÓ Û˘ÚÌ¿ÙˆÓ Ì ηϋ ÂÊ·ÚÌÔÁ‹ ÛÙ· ·Á·ÏÈ· ı· Ú¤-ÂÈ Ó· ·ÔʇÁÂÙ·È Î·Ù¿ ÙËÓ ·Ú¯È΋ ÂȤ‰ˆÛË Î·È¢ı˘ÁÚ¿ÌÌÈÛË ÙˆÓ ‰ÔÓÙÈÒÓ ÁÈ·Ù› ıˆÚÂ›Ù·È ˆ˜ ¤¯ÂÈ ˆ˜·ÔÙ¤ÏÂÛÌ· ·ÓÂÈı‡ÌËÙ˜ ''·ÏÈÓ‰ÚÔÌÈΤ˜'' ÌÂÙ·ÎÈÓ‹-ÛÂȘ ÙˆÓ ÚÈ˙ÒÓ, ·˘Í¿ÓÔÓÙ·˜ ÙÔ ¯ÚfiÓÔ Ù˘ ıÂڷ›·˜ ηÈÙÔÓ Î›Ó‰˘ÓÔ ·ÔÚÚfiÊËÛ˘ ÙˆÓ ÚÈ˙ÒÓ. ™ÙË Ê¿ÛË ·˘Ù‹Â›Ó·È ÚÔÙÈÌfiÙÂÚÔ Ó· ‰È¢ıÂÙÔ‡ÓÙ·È ÚÒÙ· ÔÈ Ì‡Ï˜ ÙˆÓ‰ÔÓÙÈÒÓ, Ì ÛÙÚÔÁÁ˘Ï¿ Û‡ÚÌ·Ù· ÌÈÎÚfiÙÂÚ˘ ‰È·ÙÔÌ‹˜(Proffit Î·È Û˘Ó., 2007). ŒÂÈÙ·, Â›Ó·È ‰˘Ó·Ù‹ Ë ¯Ú‹ÛËÔÚıÔÁÒÓÈˆÓ Û˘ÚÌ¿ÙˆÓ Ni-Ti ÌÂÁ¿Ï˘ ‰È·ÙÔÌ‹˜, Û ۯÂ-ÙÈο ÚÒÈÌ· ÛÙ¿‰È· Ù˘ ıÂڷ›·˜, ÂÈÙÚ¤ÔÓÙ·˜ Ù·˘Ùfi-¯ÚÔÓ· ÙËÓ ÂȤ‰ˆÛË, ÙËÓ Â˘ı˘ÁÚ¿ÌÌÈÛË, ÙË ‰ÈfiÚıˆÛËÙˆÓ ÛÙÚÔÊÒÓ Î·È ÙÔÓ ¤ÏÂÁ¯Ô Ù˘ ÛÙÚ¤„˘ (torque). ™Â ÔÚÈṲ̂Ó˜ ÂÚÈÙÒÛÂȘ, Û ·˘Ù‹ ÙË Ê¿ÛË ¯ÚËÛÈÌÔÔÈ-Ô‡ÓÙ·È ÔÈ ÂӉȿÌÂÛ˜ ‰È·‚·ıÌ›ÛÂȘ Û˘ÚÌ¿ÙˆÓ ·˘ÛÙÚ·-ÏÈ·ÓÔ‡ Ù‡Ô˘ ÁÈ· ÙË ‰ÈfiÚıˆÛË Ù˘ ·˘ÍË̤Ó˘ ηٷÎfi-Ú˘Ê˘ ÂÈÎ¿Ï˘„˘ ÙˆÓ ÙÔ̤ˆÓ (ÙfiÍ· Ù‡Ô˘ utility ‹·ÓÙ›ÛÙÚÔÊ˘ η̇Ï˘ Spee), ΢ڛˆ˜ ÏfiÁˆ Ù˘ ·˘ÍË̤-Ó˘ ·ÓÙ›ÛÙ·Û‹˜ ÙÔ˘˜ Û ϷÛÙÈ΋ ·Ú·ÌfiÚʈÛË ·fiÂ͈ÁÂÓ›˜ ·Ú¿ÁÔÓÙ˜, fiˆ˜ ÔÈ ‰˘Ó¿ÌÂȘ Ô˘ ·Ó·Ù‡Û-ÛÔÓÙ·È Î·Ù¿ ÙË Ì¿ÛËÛË (Drake Î·È Û˘Ó., 1982). ∆Ô ˘„ËÏfi̤ÙÚÔ ÂÏ·ÛÙÈÎfiÙËÙ·˜ Î·È Ë ·ÓÙ›ÛÙÔÈ¯Ë ·˘ÍË̤ÓË ·Î·Ì„›·ÙˆÓ Û˘ÚÌ¿ÙˆÓ ·˘ÙÒÓ ˘·ÁÔÚÂ‡Ô˘Ó ÙË ¯Ú‹ÛË Û˘ÚÌ¿ÙˆÓÌÈÎÚfiÙÂÚ˘ ‰È·ÙÔÌ‹˜ ‹ ÙËÓ ·‡ÍËÛË ÙÔ˘ Ì‹ÎÔ˘˜ ÙÔ˘ Û‡Ú-Ì·ÙÔ˜ Ì ‰È·ÌfiÚʈÛË ·ÁÎ‡ÏˆÓ ÁÈ· ÙËÓ Â˘ı˘ÁÚ¿ÌÌÈÛËÎ·È ÙËÓ ÂȤ‰ˆÛË ÙˆÓ Ô‰ÔÓÙÈÎÒÓ ÙfiÍˆÓ (Krishnan ηÈKumar, 2004a; Verstrynge Î·È Û˘Ó., 2006).√ÔÈÔ‰‹ÔÙ ۇÚÌ· ÂÈÏÂÁ› ÁÈ· ÙËÓ ·Ú¯È΋ ¢ı˘ÁÚ¿Ì-ÌÈÛË ÙˆÓ ‰ÔÓÙÈÒÓ, Â›Ó·È ÛËÌ·ÓÙÈÎfi Ó· ÚÔÛ‰¤ÓÂÙ·È ¯·Ï·-Ú¿ ÛÙ· ·Á·ÏÈ·, ÒÛÙ ӷ ¤¯ÂÈ ÙÔ Û‡ÚÌ· ÙË ‰˘Ó·ÙfiÙËÙ·‰ÈÔÏ›ÛıËÛ˘ ÛÙȘ ˘Ô‰Ô¯¤˜ ÙˆÓ ·ÁÎ˘Ï›ˆÓ. ªÂ ÙÔÓ ÙÚfiÔ·˘Ùfi ıˆÚÂ›Ù·È ˆ˜ ÂÈÙ·¯‡ÓÂÙ·È ÛËÌ·ÓÙÈο ÙÔ Û˘ÁÎÂ-ÎÚÈ̤ÓÔ ÛÙ¿‰ÈÔ Ù˘ ıÂڷ›·˜.

Asgharnia MK, Brantley WA. Comparison of bending and tensiontests for orthodontic wires. Am J Orthod Dentofacial Orthop1986;89:228-35.

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Bock JJ, Fraenzel W, Bailly J, Gernhardt CR, Fuhrmann RA. Influenceof different brazing and welding methods on tensile strengthand microhardness of orthodontic stainless steel wire. Eur JOrthod 2008;30:396-400.

Bourauel C, Scharold W, Jäger A, Eliades T. Fatigue failure of as-received and retrieved NiTi orthodontic archwires. Dent Mater2008;24:1095-101.

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Bradley TG, Brantley WA, Culbertson B. Differential scanningcalorimetry (DSC) analyses of superelastic and nonsuperelastici-ty nickel-titanium orthodontic wires. Am J Orthod DentofacialOrthop 1996;109:589-97.

Brantley WA. Orthodontic wires, in: Brantley WA, Eliades T, eds.Orthodontic materials: scientific and clinical aspects. Stuttgard:Thieme, 2001: 91-9.

Brantley WA, Webb CS, Soto U, Cai Z, McCoy BP. X-ray diffractionanalyses of Copper Ni-Ti orthodontic wires. J Dent Res1997;76:401.

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Burstone CJ, Qin B, Morton JY. Chinese NiTi wire: A new orthodonticalloy. Am J Orthod 1985;87:445-52.

Burstone CJ. Variable-modulus orthodontics. Am J Orthod1981;80:81-6.

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Cash A, Curtis R, Garrigia-Majo D, McDonald F. A comparative studyof the static and kinetic frictional resistance of titanium molyb-denum alloy archwires in stainless steel brackets. Eur J Orthod2004;26:105-11.

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Elayyan F, Silikas N, Bearn D. Mechanical properties of coated super-elastic archwires in conventional and self-ligating orthodonticbrackets. Am J Orthod Dentofacial Orthop 2010;137:213-7.

Eliades T, Athanasiou AE. In vivo aging of orthodontic alloys: impli-cations for corrosion potential, nickel release, and biocompati-bility. Angle Orthod 2002;72:222-37.

Eliades T, Eliades G, Athanasiou A, Bradley TG. Surface characteriza-tion of retrieved NiTi orthodontic archwires. Eur J Orthod

π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires HELLENIC ORTHODONTIC REVIEW

62 HELLENIC ORTHODONTIC REVIEW 2011 ñ VOLUME 14 ñ ISSUE 1

∆· ˘ÂÚÂÏ·ÛÙÈο Û‡ÚÌ·Ù· ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘ Î·È Ù· Û‡Ú-Ì·Ù· Ì ÌÓ‹ÌË Û¯‹Ì·ÙÔ˜ Â›Ó·È ¯Ú‹ÛÈÌ· ÂΛ fiÔ˘ ··È-ÙÔ‡ÓÙ·È ÌÂÁ¿Ï˜ ·Ú·ÌÔÚÊÒÛÂȘ ÙÔ˘ Û‡ÚÌ·ÙÔ˜ ÁÈ· ÙËÓÙÔÔı¤ÙËÛË ÙÔ˘, fiˆ˜ Û ÂÚÈÙÒÛÂȘ Ì ¤ÓÙÔÓÔ Û˘Óˆ-ÛÙÈÛÌfi (Bartzela Î·È Û˘Ó., 2007). ¶Ú¤ÂÈ Ó· ÙÔÓÈÛÙ› ˆ˜Ë ¯Ú‹ÛË ÙˆÓ ÏÈÁfiÙÂÚÔ ¿Î·ÌÙˆÓ Û˘ÚÌ¿ÙˆÓ, fiˆ˜ Ù·˘ÂÚÂÏ·ÛÙÈο Û‡ÚÌ·Ù· NiTi, ÛÙ· ·Ú¯Èο ÛÙ¿‰È· Ù˘ıÂڷ›·˜, ÚÔÙ›ÓÂÙ·È Ó· Á›ÓÂÙ·È fiÙ·Ó Ô ˘¿Ú¯ˆÓ Û˘Óˆ-ÛÙÈÛÌfi˜ Â›Ó·È Û¯ÂÙÈο Û˘ÌÌÂÙÚÈÎfi˜. ∂ȉ¿Ïψ˜, ˘¿Ú¯ÂÈ ÔΛӉ˘ÓÔ˜ ¢ı˘ÁÚ¿ÌÌÈÛ˘ ÙˆÓ ‰ÔÓÙÈÒÓ Ì ٷ˘Ùfi¯ÚÔÓË·ÒÏÂÈ· ÙÔ˘ Û¯‹Ì·ÙÔ˜ ÙÔ˘ ÙfiÍÔ˘ (Proffit Î·È Û˘Ó.,2007).√È ∫usy Î·È Stevens (1987) ·Ó·Ê¤ÚÔ˘Ó ˆ˜ ¤Ó· ÙÚ›Îψ-ÓÔ Û‡ÚÌ· ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· 0,015 ÈÓÙÛÒÓ ¤¯ÂÈ ÌÂÁ·-χÙÂÚÔ Â‡ÚÔ˜ ‰Ú¿Û˘ ·fi Û˘Ì‚·ÙÈο Û‡ÚÌ·Ù· ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘ Î·È ‚-ÙÈÙ·Ó›Ô˘ ›‰ÈˆÓ ‹ ÌÂÁ·Ï‡ÙÂÚˆÓ ‰È·ÛÙ¿ÛÂ-ˆÓ. √È ›‰ÈÔÈ Û˘ÁÁÚ·Ê›˜ ˘ÔÛÙËÚ›˙Ô˘Ó ˆ˜ Ù· ÔχÎψ-Ó· Û‡ÚÌ·Ù· ÌÔÚÔ‡Ó Ó· Û˘ÁÎÚÈıÔ‡Ó Ì ·ÚÎÂÙ¿ ηϿ·ÔÙÂϤÛÌ·Ù· Ì ۇÚÌ·Ù· ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘ Î·È ›Ûˆ˜ Ó··ÔÙÂÏÔ‡Ó ÌÈ· ηϋ ÂÓ·ÏÏ·ÎÙÈ΋ ÙˆÓ ·ÎÚÈ‚fiÙÂÚˆÓ·˘ÙÒÓ Û˘ÚÌ¿ÙˆÓ ÁÈ· ÙËÓ ·Ú¯È΋ ÂȤ‰ˆÛË (QuintaoÎ·È Û˘Ó. 2009). ∫ÏÈÓÈΤ˜ ÌÂϤÙ˜, Û˘ÁÎÚ›ÓÔÓÙ·˜ ˘ÂÚÂÏ·-ÛÙÈο Û‡ÚÌ·Ù· NiTi, Û˘Ì‚·ÙÈο Û‡ÚÌ·Ù· NiTi Î·È Ôχ-Îψӷ Û‡ÚÌ·Ù· ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚·, ‰ÂÓ ÂÓÙfiÈÛ·ÓÛËÌ·ÓÙÈΤ˜ ‰È·ÊÔÚ¤˜ fiÛÔÓ ·ÊÔÚ¿ ÙËÓ ÈηÓfiÙËÙ· Î·È ÙËÓÙ·¯‡ÙËÙ· ·Ú¯È΋˜ ¢ı˘ÁÚ¿ÌÌÈÛ˘ Î·È ÂȤ‰ˆÛ˘ ÙˆÓ‰ÔÓÙÈÒÓ (West Î·È Û˘Ó., 1995; Evans Î·È Û˘Ó., 1998).∞ÎfiÌË, ‰‡Ô Û˘ÛÙËÌ·ÙÈΤ˜ ·Ó·ÛÎÔ‹ÛÂȘ Ô˘ ÌÂϤÙËÛ·ÓÙËÓ ÈηÓfiÙËÙ· ¢ı˘ÁÚ¿ÌÌÈÛ˘ Î·È ÙËÓ ÚfiÎÏËÛË fiÓÔ˘·fi ‰È¿ÊÔÚÔ˘˜ Ù‡Ô˘˜ ÌÔÓfiÎÏˆÓˆÓ Û˘ÚÌ¿ÙˆÓ ÓÈÎÂÏ›-Ô˘-ÙÈÙ·Ó›Ô˘ Î·È ÔχÎÏˆÓˆÓ Û˘ÚÌ¿ÙˆÓ ·ÓÔÍ›‰ˆÙÔ˘¯¿Ï˘‚· ‰ÂÓ ÂÓÙfiÈÛ·Ó ÛËÌ·ÓÙÈ΋ ‰È·ÊÔÚ¿ (Riley ηÈBearn, 2009; Wang Î·È Û˘Ó., 2010). ∆· ÌÂÛ·›· ÛÙ¿‰È· Ù˘ ÔÚıÔ‰ÔÓÙÈ΋˜ ıÂڷ›·˜ Û˘¯Ó¿··ÈÙÔ‡Ó Î·Ù¿ÏÏËÏË ‰È·ÌfiÚʈÛË ÙˆÓ Û˘ÚÌ¿ÙˆÓ Î·ÈÛ˘ÁÎfiÏÏËÛË ‰È·ÊfiÚˆÓ ÂÌ‚ÈÔÌ˯·ÓÈÎÒÓ ‚ÔËıËÌ¿ÙˆÓ.∆· Û‡ÚÌ·Ù· ‚-ÙÈÙ·Ó›Ô˘ ·Ú¿ ÙÔ ˘„ËÏfiÙ·ÙÔ ÎfiÛÙÔ˜ ÙÔ˘˜¯·Ú·ÎÙËÚ›˙ÔÓÙ·È ·fi Ôχ ηϋ ÈηÓfiÙËÙ· ‰È·ÌfiÚʈ-Û˘, Ë ÔÔ›· ÛÂ Û˘Ó‰˘·ÛÌfi Ì ÙËÓ Ú·ÁÌ·ÙÈ΋ ÈηÓfiÙË-Ù· Û˘ÁÎfiÏÏËÛ˘ ¯ˆÚ›˜ ÙË ¯Ú‹ÛË Û˘ÁÎÔÏÏËÙÈÎÔ‡ ̤ÛÔ˘Ù· ηıÈÛÙ¿ Û‡ÚÌ·Ù· ÂÈÏÔÁ‹˜ fiÙ·Ó ··ÈÙÂ›Ù·È Ë Î·Ù·-Û΢‹ ÔχÏÔÎˆÓ ‰È·ÌÔÚÊÒÛˆÓ. ∂ÈÚfiÛıÂÙ·,·Ú¤¯Ô˘Ó ÌÂÁ·Ï‡ÙÂÚÔ Â‡ÚÔ˜ ÂÓÂÚÁÔÔ›ËÛ˘ Î·È ËÈfiÙÂ-Ú˜ ‰˘Ó¿ÌÂȘ ·fi Ù· Û‡ÚÌ·Ù· ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· ‹¯ÚˆÌ›Ô˘-ÎÔ‚·ÏÙ›Ô˘ (Kapila Î·È Sachdeva, 1989; Kusy,1997; Johnson, 2003). ™Â ÂÚÈÙÒÛÂȘ Ô˘ ‰ÂÓ ··ÈÙ›ٷȉȷÌfiÚʈÛË ÙˆÓ Û˘ÚÌ¿ÙˆÓ ÌÔÚÔ‡Ó Ó· ÙÔÔıÂÙËıÔ‡ÓÎ·È Û‡ÚÌ·Ù· ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘ ÌÂÁ¿Ï˘ ‰È·ÙÔÌ‹˜ (Kusy,1997). ŸÙ·Ó ÂȉÈÒÎÂÙ·È Ë ÌÂٷΛÓËÛË ÂÓfi˜ Û˘ÛÙ‹Ì·ÙÔ˜·ÁÎ˘Ï›Ô˘-‰ÔÓÙÈÔ‡ ηٿ Ì‹ÎÔ˜ ÂÓfi˜ Û‡ÚÌ·ÙÔ˜ Ë ¯·ÌËÏ‹

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Huang HH, Chiu YH, Lee TH, Wu SC, Yang HW, Su KH, Hsu CC. Ionrelease from NiTi orthodontic wires in artificial saliva with vari-

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ÙÚÈ‚‹ ¢ÓÔ› ÙË ÌÂٷΛÓËÛË. ™˘ÓÂÒ˜, ÌÈÎÚfiÙÂÚ· ÌÂÁ¤ıËÛÙÚfiÁÁ˘ÏˆÓ Û˘ÚÌ¿ÙˆÓ ·fi ·ÓÔÍ›‰ˆÙÔ ¯¿Ï˘‚· ıˆ-ÚÔ‡ÓÙ·È ÂÚÈÛÛfiÙÂÚÔ Î·Ù¿ÏÏËÏ· ÁÈ· ·˘Ù‹ ÙËÓ ÂÚ›Ùˆ-ÛË (Kapila Î·È Sachdeva, 1989; Kusy, 1997). ™ÙÔ ÛËÌÂ›Ô ·˘Ùfi ÎÚ›ÓÂÙ·È ÛÎfiÈÌÔ Ó· ÙÔÓÈÛÙ› ˆ˜ ηٿÙË ‰È¿ÚÎÂÈ· Ù˘ ıÂڷ›·˜ Ë ·ÓÙ›ÛÙ·ÛË ÛÙËÓ Î›ÓËÛË ÂÓfi˜·ÁÎ˘Ï›Ô˘ ηٿ Ì‹ÎÔ˜ ÂÓfi˜ Û‡ÚÌ·ÙÔ˜ ÌÂÚÈÎÒ˜ Î·È ÌfiÓÔÔÊ›ÏÂÙ·È ÛÙËÓ ÙÚÈ‚‹ (Burrow, 2009). ∂ÚÁ·ÛÙËÚȷΤ˜ÌÂϤÙ˜ ‰Â›¯ÓÔ˘Ó fiÙÈ Ë Û‡Ó‰ÂÛË ÙÔ˘ Û‡ÚÌ·ÙÔ˜ ÛÙȘÁˆÓ›Â˜ ÙÔ˘ ·ÁÎ˘Ï›Ô˘ (binding), Ë ÔÔ›· Û˘Ì‚·›ÓÂÈ Ï›ÁÔÌÂÙ¿ ÙËÓ ¤Ó·ÚÍË Ù˘ Ô‰ÔÓÙÈ΋˜ ÌÂٷΛÓËÛ˘, ·›˙ÂÈ ÔχÛËÌ·ÓÙÈÎfi ÚfiÏÔ (Thorstenson Î·È Kusy, 2002; HamdanÎ·È Rock, 2008), ÂÓÒ Ë ÌfiÓÈÌË ·Ú·ÌfiÚʈÛË ÙÔ˘ Û‡Ú-Ì·ÙÔ˜ ·fi ‰ËÌÈÔ˘ÚÁ›· ÂÁÎÔ‹˜ (notching), Ë ÔÔ›· ÛÙ·-Ì·Ù¿ ÚÔÛˆÚÈÓ¿ ÙËÓ ÌÂٷΛÓËÛË, Â›Ó·È Â›Û˘ ÛËÌ·ÓÙÈ΋(Articolo Î·È Û˘Ó., 2000; Burrow, 2009). ™˘ÓÂÒ˜, Ë·ÓÙ›ÛÙ·ÛË ÛÙËÓ ÔÚıÔ‰ÔÓÙÈ΋ ÌÂٷΛÓËÛË ‰ÂÓ Â›Ó·È ¤Ó··Ïfi Ê·ÈÓfiÌÂÓÔ Ô˘ ÌÔÚ› Ó· ·Ó··Ú·¯ı› Î·È ÂÏÂÁ-¯ı› ·ÎÚÈ‚Ò˜ Ì ÂÚÁ·ÛÙËÚÈ·ÎÔ‡˜ ÂϤÁ¯Ô˘˜ ÛÙ·ÙÈ΋˜Â›Ù ÎÈÓËÙÈ΋˜ ÙÚÈ‚‹˜. ∞ÓÙÈı¤Ùˆ˜, Â›Ó·È ¤Ó· ÔÏ˘·Ú·ÁÔ-ÓÙÈÎfi Ê·ÈÓfiÌÂÓÔ Û‡Ó‰ÂÛ˘-·ÂÏ¢ı¤ÚˆÛ˘ (binding-and-release) Ô˘ Â›Ó·È ‰‡ÛÎÔÏÔ Ó· ÚÔÛÔÌÔȈı› ÌÂÂÈÙ˘¯›· in vitro ÒÛÙ ӷ ÌÂÏÂÙËı› ·ÚÎÒ˜ (Swartz,2007; Burrow, 2009). ŒÙÛÈ, ÔÈ ÂÚÁ·ÛÙËÚȷΤ˜ ÌÂϤÙ˜ Ô˘‰Â›¯ÓÔ˘Ó fiÙÈ Ù· Û‡ÚÌ·Ù· SS ˘ÂÚ¤¯Ô˘Ó fiÏˆÓ ÙˆÓ ¿ÏψÓÎ·È È‰È·›ÙÂÚ· ÙˆÓ Û˘ÚÌ¿ÙˆÓ ·fi ÎÚ¿Ì·Ù· ÙÈÙ·Ó›Ô˘ fiÛÔÓ·ÊÔÚ¿ ÙÔ Ì¤ÁÂıÔ˜ Ù˘ ÙÚÈ‚‹˜ (Peterson Î·È Û˘Ó., 1982;Kusy Î·È Whitley, 1990; Kusy Î·È Whitley, 1989; KapilaÎ·È Û˘Ó., 1990; Cash Î·È Û˘Ó., 2004; Krishnan Î·È Kumar,2004a) ÂӉ¯Ô̤ӈ˜ Ó· ¤¯Ô˘Ó ÌÈÎÚ‹ ÛËÌ·Û›· Û ÎÏÈÓÈÎfi›‰Ô.™Ù· ÙÂÏÂ˘Ù·›· ÛÙ¿‰È· Ù˘ ıÂڷ›·˜, fiÔ˘ ··ÈÙÔ‡ÓÙ·ÈÌÈÎÚfiÙÂÚ˜ ÌÂÙ·ÎÈÓ‹ÛÂȘ, ÌÂÁ·Ï‡ÙÂÚË ÛÙ·ıÂÚfiÙËÙ· ηȤÏÂÁ¯Ô˜ Ù˘ ÛÙÚ¤„˘ (torque), Ë ÈηÓfiÙËÙ· ‰È·ÌfiÚʈÛË˜Î·È Ë ·Î·Ì„›· ÙˆÓ Û˘ÚÌ¿ÙˆÓ ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚· (‹ÂÓ·ÏÏ·ÎÙÈο ¯ÚˆÌ›Ô˘-ÎÔ‚·ÏÙ›Ô˘) ηıÈÛÙ¿, ·˘Ù¿ Ù· Û‡Ú-Ì·Ù·, Û‡ÚÌ·Ù· ÂÈÏÔÁ‹˜ (Kapila Î·È Sachdeva, 1989;Kusy, 1997). ™Â ÂÚÈÙÒÛÂȘ Ô˘ ÔÈ ··ÈÙÔ‡ÌÂÓ˜ ‰ÈÔÚ-ıÒÛÂȘ Â›Ó·È Û¯ÂÙÈο ÌÂÁ¿Ï˜, Â›Ó·È ÚÔÙÈÌfiÙÂÚË Ë ¯Ú‹ÛËÛ˘ÚÌ¿ÙˆÓ ‚-ÙÈÙ·Ó›Ô˘ ÁÈ· ÙËÓ Â›Ù¢ÍË ÌÂÁ·Ï‡ÙÂÚԢ‡ÚÔ˘˜ ÂÓÂÚÁÔÔÈ‹ÛÂˆÓ Î·È ÙËÓ ·ÔÊ˘Á‹ ¿ÛÎËÛ˘˘¤ÚÌÂÙÚˆÓ ‰˘Ó¿ÌÂˆÓ ÛÙ· ‰fiÓÙÈ· (Johnson, 2003). ∏¯·ÌËÏ‹ ·Î·Ì„›· ÙˆÓ Û˘ÚÌ¿ÙˆÓ ÓÈÎÂÏ›Ô˘-ÙÈÙ·Ó›Ô˘ ٷηıÈÛÙ¿ ·Î·Ù¿ÏÏËÏ· ÁÈ· Ù· ÙÂÏÈο ÛÙ¿‰È· Ù˘ ıÂڷ›·˜.∫¿ÔȘ ÊÔÚ¤˜, ÔÚıÔÁÒÓÈ· ÔχÎψӷ Û‡ÚÌ·Ù· ·ÓÔÍ›-‰ˆÙÔ˘ ¯¿Ï˘‚· ¯ÚËÛÈÌÔÔÈÔ‡ÓÙ·È Î·Ù¿ ÙËÓ ÙÂÏÈ΋ ‰È¢-ı¤ÙËÛË ÙˆÓ Ô‰ÔÓÙÈÎÒÓ ÙfiÍˆÓ (settling), ÏfiÁˆ ÙÔ˘ fiÙÈÂÈÙÚ¤Ô˘Ó ÌÈÎÚ¤˜ Ô‰ÔÓÙÈΤ˜ ÌÂÙ·ÎÈÓ‹ÛÂȘ ‰È·ÙËÚÒÓÙ·˜·Ú¿ÏÏËÏ· ÙË Û¯ÂÙÈ΋ ÙÂÏÈ΋ ı¤ÛË ÙˆÓ ‰ÔÓÙÈÒÓ. ∞ÎfiÌË, Ù· ÔχÎψӷ Û‡ÚÌ·Ù· ¤¯Ô˘Ó ¢Ú›· ÂÊ·ÚÌÔÁ‹

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E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires

π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires HELLENIC ORTHODONTIC REVIEW

64 HELLENIC ORTHODONTIC REVIEW 2011 ñ VOLUME 14 ñ ISSUE 1

Î·È Î·Ù¿ ÙË Û˘ÁÎÚ¿ÙËÛË Ù˘ ÔÚıÔ‰ÔÓÙÈ΋˜ ıÂڷ›·˜,Ô˘ Á›ÓÂÙ·È Û˘Ó‹ıˆ˜ Ì ÛÙÚÔÁÁ˘Ï¿ Û‡ÚÌ·Ù· (0,0215ÈÓÙÛÒÓ) Ù· ÔÔ›· Û˘ÁÎÔÏÏÔ‡ÓÙ·È Û fiÏ· Ù· ÚfiÛıÈ·‰fiÓÙÈ· (Zachrisson, 2007). ¶ÚÔÙ›ÓÂÙ·È ÙÔ Û‡ÚÌ· Ó· ˘Ê›-ÛÙ·Ù·È Î¿ÔÈ· ÌÔÚÊ‹ ıÂÚÌÈ΋˜ ηÙÂÚÁ·Û›·˜ ÚÈÓ ÙËÓÙÂÏÈ΋ ÙÔÔı¤ÙËÛË ÙÔ˘ ÁÈ· ·ÔÌ¿ÎÚ˘ÓÛË Ù˘¯fiÓ ˘ÔÏÂÈ-fiÌÂÓˆÓ Ù¿ÛÂˆÓ (residual stresses).

∂∂••∂∂§§ππ••∏∏ -- ∞∞π𙙣£∏∏∆∆ππ∫∫∞∞ ™™ÀÀƒƒªª∞∞∆∆∞∞

ª¤¯ÚÈ Û‹ÌÂÚ· ‰ÂÓ ¤¯ÂÈ ‚ÚÂı› ÙÔ ·ÈÛıËÙÈÎfi Û‡ÚÌ· Ô˘Ó· Û˘Óԉ‡ÂÙ·È ·fi ÙȘ ··Ú·›ÙËÙ˜ Ì˯·ÓÈΤ˜ ȉÈfiÙËÙ˜,Ô˘ ı· ÙÔ Î·ıÈÛÙÔ‡Ó Ô˘ÛÈ·ÛÙÈο ¯Ú‹ÛÈÌÔ ÁÈ· ÙËÓ ÚfiÔ-‰Ô Ù˘ ÔÚıÔ‰ÔÓÙÈ΋˜ ıÂڷ›·˜. √È ‰‡Ô Ù‡ÔÈ ·ÈÛıËÙÈ-ÎÒÓ Û˘ÚÌ¿ÙˆÓ Ô˘ ˘¿Ú¯Ô˘Ó Â›Ó·È Ù· ÂÈÎ·Ï˘Ì̤ӷÌÂÙ·ÏÏÈο (coated) Î·È Ù· ÂÓÈÛ¯˘Ì¤Ó· Ì ›Ó˜ ÔÏ˘ÌÂÚ‹(fiber-reinforced). ∞fi ·˘Ù¿, Ù· ÌÔÓ·‰Èο ‰È·ı¤ÛÈÌ·ÚÔ˜ ÎÏÈÓÈ΋ ¯Ú‹ÛË Â›Ó·È Ù· ÂÈÎ·Ï˘Ì̤ӷ, ·ÊÔ‡ Ù·ÔÏ˘ÌÂÚ‹ Â›Ó·È ·ÎfiÌË Û ÂÈÚ·Ì·ÙÈÎfi ›‰Ô. ∆· ˘ÏÈÎ¿Ô˘ ¯ÚËÛÈÌÔÔÈÔ‡ÓÙ·È ÁÈ· ÙËÓ ÂÈÎ¿Ï˘„Ë Â›Ó·È Û˘ÓıÂÙÈ-Τ˜ ÊıÔÚÈÔ‡¯Â˜ ÚËÙ›Ó˜, Teflon ›Ù ÂÔÍÈΤ˜ ÚËÙ›Ó˜ ·fiÔÏ˘ÙÂÙÚ·ÊıÔÚÔ·Èı˘Ï¤ÓÈÔ (Elayyan Î·È Û˘Ó., 2008;Elayyan Î·È Û˘Ó., 2010). ∆· ÏÂÁfiÌÂÓ· Î·È ''¿ÛÚ· Û‡Ú-Ì·Ù·'' Û˘¯Ó¿ ˘Ô·ÙÔ˘Ó ÛÙȘ Ì·ÛËÙÈΤ˜ ‰˘Ó¿ÌÂȘ ‹ÛÙËÓ ÂÓ˙˘ÌÈ΋ ‰Ú·ÛÙËÚÈfiÙËÙ· Ù˘ ÛÙÔÌ·ÙÈ΋˜ ÎÔÈÏfiÙËÙ·˜ÂÓÙfi˜ ÙÚÈÒÓ Â‚‰ÔÌ¿‰ˆÓ ¯Ú‹Û˘ in vivo (Kusy, 1997).∞ӷʤÚÂÙ·È Â›Û˘ ¯ÚˆÌ·ÙÈ΋ ·ÛÙ¿ıÂÈ· ÙˆÓ Û˘ÚÌ¿ÙˆÓ·˘ÙÒÓ Î·È ·ÔÎ¿Ï˘„Ë ÙÔ˘ ˘ÔΛÌÂÓÔ˘ ÌÂÙ¿ÏÏÔ˘ (LimÎ·È Û˘Ó., 1994). µÚ¤ıËΠˆ˜ ÙÔ 25% Ù˘ ÂÈÎ¿Ï˘„˘¯¿ÓÂÙ·È Û 33 ̤Ú˜ ÂÓ‰ÔÛÙÔÌ·ÙÈο Î·È ¤ÙÛÈ ÙÔ Û‡ÚÌ·˘Ô‚·ıÌ›˙ÂÙ·È ·ÈÛıËÙÈο (Elayyan Î·È Û˘Ó., 2008). H ÂÈ-Î¿Ï˘„Ë Ê·›ÓÂÙ·È ˆ˜ ·Ú¯Èο ÌÂÈÒÓÂÈ ÙËÓ ÙÚÈ‚‹ ÌÂٷ͇ۇÚÌ·ÙÔ˜-·ÁÎ˘Ï›Ô˘ (Husmann Î·È Û˘Ó., 2002), ˆÛÙfiÛÔÔÈ ÙÈ̤˜ ÂÈÊ·ÓÂȷ΋˜ ·‰ÚfiÙËÙ·˜ ·˘Í¿ÓÔÓÙ·È Û‡ÓÙÔ̷ηٿ ÙËÓ ÎÏÈÓÈ΋ ¯Ú‹ÛË (Elayyan Î·È Û˘Ó., 2008). ™‡Ú-Ì·Ù· Ì ÂÈÎ¿Ï˘„Ë ·Ô‰›‰Ô˘Ó ÌÈÎÚfiÙÂÚ˜ ‰˘Ó¿ÌÂȘ ηٿÙËÓ ÊfiÚÙÈÛË Î·È ·ÔÊfiÚÙÈÛË Û ۯ¤ÛË Ì ÌË ÂÈÎ·Ï˘Ì-̤ӷ Û‡ÚÌ·Ù· ›‰È·˜ ÔÓÔÌ·ÛÙÈ΋˜ ‰È·Ì¤ÙÚÔ˘ (Elayyan ηÈÛ˘Ó., 2010). ∆Ô Â‡ÚËÌ· ·˘Ùfi, ·Ó Î·È ·Ó·ÌÂÓfiÌÂÓÔ (ÏfiÁˆÙÔ˘ ¿¯Ô˘˜ ÙÔ˘ ˘ÏÈÎÔ‡ ÂÈÎ¿Ï˘„˘ ¯ÚËÛÈÌÔÔÈ›ٷÈÛ‡ÚÌ· ÂÏ·ÊÚ¿ ÌÈÎÚfiÙÂÚ˘ ‰È·ÙÔÌ‹˜), Ú¤ÂÈ Ó· Ï·Ì‚¿-ÓÂÙ·È ˘fi„Ë ·ÊÔ‡ ÔÏÏÔ› ÔÚıÔ‰ÔÓÙÈÎÔ› ¯ÚËÛÈÌÔÔÈÔ‡Óˆ˜ Ô‰ËÁfi ÙËÓ ‰È¿ÌÂÙÚÔ ÙÔ˘ Û‡ÚÌ·ÙÔ˜ ÛÂ Û˘ÁÎÂÎÚÈ̤Ó˜ÎÏÈÓÈΤ˜ ÂÚÈÙÒÛÂȘ (Elayyan Î·È Û˘Ó., 2010).∞ÚÎÂÙ¿ ˘ÔÛ¯fiÌÂÓË Â›Ó·È Ë ¯Ú‹ÛË Û˘ÓıÂÙÈÎÒÓ ˘ÏÈÎÒÓ,Ô˘ ÂÚÈÏ·Ì‚¿ÓÔ˘Ó Ì‹ÙÚ· ÔÏ˘ÌÂÚÔ‡˜ ÂÓÈÛ¯˘Ì¤ÓË Ì›Ó˜ ˘¿ÏÔ˘ ‹ ¿ÏϘ (Zufall Î·È Kusy, 2000b; GoldbergÎ·È Burstone, 1992). ∏ ·Î·Ì„›· ÙˆÓ Û˘ÚÌ¿ÙˆÓ ·˘ÙÒÓÌÔÚ› Ó· ηıÔÚ›˙ÂÙ·È Î·Ù¿ ÙËÓ Î·Ù·Û΢‹ ¯ˆÚ›˜ ÌÂÙ·-‚ÔÏ‹ ÛÙȘ ‰È·ÛÙ¿ÛÂȘ ÙÔ˘ Û‡ÚÌ·ÙÔ˜, ÌÂÙ·‚¿ÏÏÔÓÙ·˜ ÙË

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E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires

E§§HNIKH OP£O¢ONTIKH E¶I£EøPH™H 2011 ñ TOMO™ 14 ñ TEYXO™ 1 65

ÁˆÌÂÙÚ›· ÙˆÓ ÈÓÒÓ ‹/Î·È ÙȘ ·Ó·ÏÔÁ›Â˜ ÙˆÓ ˘ÏÈÎÒÓ ÙˆÓÈÓÒÓ Î·È Ù˘ Ì‹ÙÚ·˜ Î·È ÔÏ˘ÌÂÚ›˙ÔÓÙ¿˜ Ù· ηٿÏÏËÏ·(Imai Î·È Û˘Ó., 1998; Zufall Î·È Kusy, 2000b). ªÂ ÙÔÓÙÚfiÔ ·˘Ùfi Â›Ó·È Èı·Ó‹ Ë Î·Ù·Û΢‹ ·ÎfiÌË Î·È ÔÚıÔ-ÁÒÓÈˆÓ ·ÈÛıËÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ (Fallis Î·È Kusy., 2000).ªÈ· ÚfiÛÊ·ÙË ÌÂϤÙË Î¿Ì„Ë˜ ÙÚÈÒÓ ÛËÌ›ˆÓ Û ÂÓÈÛ¯˘-̤ӷ Û˘ÓıÂÙÈο Î·È Û‡ÚÌ·Ù· ·ÓÔÍ›‰ˆÙÔ˘ ¯¿Ï˘‚·¤‰ˆÛ ÂÏȉÔÊfiÚ· ·ÔÙÂϤÛÌ·Ù· (Cacciafesta Î·È Û˘Ó.,2008).∫·ıÒ˜ Ù· Û˘ÓıÂÙÈο ˘ÏÈο ·ÓÙÈηıÈÛÙÔ‡Ó Ù· ÌÂÙ·ÏÏÈοÎÚ¿Ì·Ù· ÛÙËÓ ·ÂÚÔÓ·˘ËÁÈ΋ ‚ÈÔÌ˯·Ó›·, οÙÈ ·Ó¿ÏÔÁԷӷ̤ÓÂÙ·È Ó· Á›ÓÂÈ Û οÔÈÔ ‚·ıÌfi Î·È ÛÙËÓ ÔÚıÔ‰Ô-ÓÙÈ΋ ÛÙÔ ÂÁÁ‡˜ ̤ÏÏÔÓ (Kusy, 1997). ¶ÚfiÛÊ·Ù·, ÛÙÔÓ¢ڇÙÂÚÔ ÂÈÛÙËÌÔÓÈÎfi ÙÔ̤· ÙˆÓ ˘ÏÈÎÒÓ ¤¯Ô˘Ó ·Ú·-¯ı› ÔÏ˘ÌÂÚ‹ ˘ÏÈο Ì ÌÓ‹ÌË Û¯‹Ì·ÙÔ˜, Ù· ÔÔ›· ‚Ú‹-Î·Ó ÔÈΛϘ ‚ÈÔ˚·ÙÚÈΤ˜ ÂÊ·ÚÌÔÁ¤˜ (Lendlein Î·È Û˘Ó.,2005). ∆· ˘ÏÈο ·˘Ù¿ ÌÔÚ› Ó· ·ÔÙÂϤÛÔ˘Ó ÛÙÔ Ì¤Ï-ÏÔÓ Ì›· ‚ÈÒÛÈÌË ÂÓ·ÏÏ·ÎÙÈ΋ ÙˆÓ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘Ú-Ì¿ÙˆÓ Ô˘ ¯ÚËÛÈÌÔÔÈÔ‡ÓÙ·È Û‹ÌÂÚ· (Eliades, 2007).π‰È·›ÙÂÚÔ ÂӉȷʤÚÔÓ ·ÚÔ˘ÛÈ¿˙ÂÈ Î·È ¤Ó·˜ Ó¤Ô˜ (ÂÈÚ·-Ì·ÙÈÎfi˜) Ù‡Ô˜ ·ÈÛıËÙÈÎÒÓ ˘ÏÈÎÒÓ ÁÈ· ÔÚıÔ‰ÔÓÙÈ΋¯Ú‹ÛË Ô˘ ·Ó·Ê¤ÚÔÓÙ·È ˆ˜ ·˘ÙÔ-ÂÓÈÛ¯˘fiÌÂÓ· ÔÏ˘ÌÂ-Ú‹. ∞˘Ù¿ ηٷÛ΢¿˙ÔÓÙ·È ·fi ÔÏ˘Ê·ÈÓ˘Ï¤ÓÈÔ, ÙÔÔÔ›Ô ÂÌÊ·Ó›˙ÂÈ ¯ÚÔÓÔÂÍ·ÚÙfiÌÂÓË Ì›ˆÛË Ù¿Û˘(relaxation). ™˘Ó·ÎfiÏÔ˘ı·, Ë Èı·Ó‹ ¯Ú‹ÛË ÙÔ˘˜ ÛÙËÓÎÏÈÓÈ΋ Ú¿ÍË ı· ··ÈÙ› ÙËÓ Î·Ù·ÓfiËÛË ·˘Ù‹˜ ÙË˜Û˘ÌÂÚÈÊÔÚ¿˜ ÙˆÓ Û˘ÚÌ¿ÙˆÓ ·fi ÙÔÓ ÂȉÈÎfi ÔÚıÔ‰ÔÓÙÈ-Îfi (Goldberg Î·È Û˘Ó., 2010).

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™‹ÌÂÚ·, Ì›· ÌÂÁ¿ÏË ÔÈÎÈÏ›· ÎÚ·Ì¿ÙˆÓ ¯ÚËÛÈÌÔÔÈ›ٷÈÁÈ· ÙËÓ Î·Ù·Û΢‹ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ. ∫¿ıÂÙ‡Ô˜ Û‡ÚÌ·ÙÔ˜ ¯·Ú·ÎÙËÚ›˙ÂÙ·È ·fi Û˘ÁÎÂÎÚÈ̤Ó˜ ȉÈfi-ÙËÙ˜, ÔÈ Ôԛ˜ Ì¿ÏÈÛÙ· ÔÏϤ˜ ÊÔÚ¤˜ ‰È·Ê¤ÚÔ˘Ó ÛËÌ·-ÓÙÈο ·Ó¿ÏÔÁ· Ì ÙÔÓ Î·Ù·Û΢·ÛÙ‹. √È ‰È·ÊÔÚÂÙÈΤ˜È‰ÈfiÙËÙ˜ ÙˆÓ ÎÚ·Ì¿ÙˆÓ, ÛÂ Û˘Ó‰˘·ÛÌfi Ì ÙËÓ ÔÈÎÈÏ›·ÙˆÓ ÌÂÁÂıÒÓ Î·È ÁˆÌÂÙÚÈÒÓ, ηıÈÛÙÔ‡Ó ÙËÓ ÂÈÏÔÁ‹ÙÔ˘ ηٿÏÏËÏÔ˘ Û‡ÚÌ·ÙÔ˜ ÁÈ· ‰Â‰Ô̤ÓË ÎÏÈÓÈ΋ ÂÚ›-ÙˆÛË ÌÈ· ȉȷ›ÙÂÚ· ··ÈÙËÙÈ΋ ‰È·‰Èηۛ·.∏ ÁÓÒÛË ÙˆÓ Ì˯·ÓÈÎÒÓ Î·È Ê˘ÛÈÎÒÓ È‰ÈÔÙ‹ÙˆÓ ÙˆÓÛ˘ÚÌ¿ÙˆÓ Ô˘ ηıÔÚ›˙Ô˘Ó ˆ˜ ¤Ó· ‚·ıÌfi ÙËÓ ÎÏÈÓÈÎ‹Û˘ÌÂÚÈÊÔÚ¿ ÙÔ˘˜ Â›Ó·È ··Ú·›ÙËÙË ÁÈ· ÙËÓ Â›Ù¢ÍËÂÓfi˜ ÈηÓÔÔÈËÙÈÎÔ‡ Î·È ÚԂϤ„ÈÌÔ˘ ·ÔÙÂϤÛÌ·ÙÔ˜.™˘Ó‹ıˆ˜ Ì ÙËÓ ÚfiÔ‰Ô Ù˘ ıÂڷ›·˜ ÂÈϤÁÔÓÙ·È Û‡Ú-Ì·Ù· Ì ÚÔԉ¢ÙÈο ·˘Í·ÓfiÌÂÓË ·Î·Ì„›·. øÛÙfiÛÔ,ηıÒ˜ ÙÔ È‰·ÓÈÎfi Û‡ÚÌ· ‰ÂÓ ¤¯ÂÈ ·Ó·Î·Ï˘Êı› ̤¯ÚÈÛ‹ÌÂÚ·, ÙÔ Î¿ı ۇÚÌ· ÌÔÚ› Ó· ·ÔÙÂÏ› ηٿÏÏËÏË‹ ÌË ÂÈÏÔÁ‹ ·Ó¿ÏÔÁ· Ì ÙÔ ÛÙ¿‰ÈÔ Ù˘ ıÂڷ›·˜ Î·È ÙÔÂȉȈÎfiÌÂÓÔ ÎÏÈÓÈÎfi ·ÔÙ¤ÏÂÛÌ·. ∏ ÂÈÏÔÁ‹ Î·È Ë ‰È·-

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π‰ÈfiÙËÙ˜ Î·È ÂÊ·ÚÌÔÁ¤˜ ÔÚıÔ‰ÔÓÙÈÎÒÓ Û˘ÚÌ¿ÙˆÓ / Properties and applications of orthodontic wires HELLENIC ORTHODONTIC REVIEW

66 HELLENIC ORTHODONTIC REVIEW 2011 ñ VOLUME 14 ñ ISSUE 1

‰Ô¯‹ ÙˆÓ Û˘ÚÌ¿ÙˆÓ ‰ÂÓ ı· Ú¤ÂÈ Ó· Á›ÓÂÙ·È ÂÈfiÏ·È·Î·È Ó· Â›Ó·È ÚÔηıÔÚÈṲ̂ÓË ÁÈ· fiÏÔ˘˜ ÙÔ˘˜ ·ÛıÂÓ›˜,·ÏÏ¿ Ó· ‚·Û›˙ÂÙ·È ÛÙËÓ ˘¿Ú¯Ô˘Û· ÂÈÛÙËÌÔÓÈ΋ ÙÂÎÌË-Ú›ˆÛË Î·È ÛÙȘ ÎÏÈÓÈΤ˜ ··ÈÙ‹ÛÂȘ οı ÂÚ›ÙˆÛ˘.∏ ÂͤÏÈÍË ÛÙÔ ¯ÒÚÔ ÙˆÓ ‚ÈÔ¸ÏÈÎÒÓ ¤¯ÂÈ ÂÈʤÚÂÈ ·ÈÛÈfi-‰ÔÍ· ·ÔÙÂϤÛÌ·Ù· Û¯ÂÙÈο Ì ÙË ‰ËÌÈÔ˘ÚÁ›· ·ÈÛıËÙÈ-ÎÒÓ Û˘ÚÌ¿ÙˆÓ Ì ÈηÓÔÔÈËÙÈΤ˜ ȉÈfiÙËÙ˜. º·›ÓÂٷȈ˜ ÛÙÔ ¿ÌÂÛÔ Ì¤ÏÏÔÓ Ù· Û‡ÚÌ·Ù· ·˘Ù¿ ı· ‚Ú›ÛÎÔÓÙ·ÈÛÙË ‰È¿ıÂÛË ÙÔ˘ ÔÚıÔ‰ÔÓÙÈÎÔ‡ ·˘Í¿ÓÔÓÙ·˜ ·ÎfiÌËÂÚÈÛÛfiÙÂÚÔ ÙÔ Â‡ÚÔ˜ ÙˆÓ ‰È·ı¤ÛÈÌˆÓ ÂÈÏÔÁÒÓ.

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E-mail: ntopouz@dent.auth.gr

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RReepprriinntt rreeqquueessttss ttoo::Nikolaos TopouzelisAssistant ProfessorDepartment of OrthodonticsSchool of DentistryAristotle University of Thessaloniki54124 Thessaloniki

E-mail: ntopouz@dent.auth.gr