Ormco’s inspire!™ aesthetic bracketrepresents an evolution in technologythat dates back to the mid ’80s. It isthe culmination of 15 plus years in alearning process, capitalizing on themistakes and progress in ceramic andorthodontic bracket technology.

Since 1984, we have seen polycrys-talline and single-crystal aluminumoxide brackets of several designs. Theprofession witnessed a period of enameldamage from ceramic brackets, ranging

from enamel attrition to outright enamel fractures.This unfortunate experience provided a valuablelesson about controlling the bond strengths of theserigid materials and recognizing that the cliniciancannot treat ceramic brackets the same as metal.

When “A” Company produced the Star�re®

sapphire bracket (a single-crystal aluminum oxide),clinicians appreciated the clarity of the single-crystalmaterial but experienced high fracture rates due todesign and manufacturing �aws. Ormco also dabbledfor a short time with a single-crystal bracket called

Dr. Michael Swartz is currently the Clinical Director forOrthodontic Training and Seminars at Ormco where heorganizes and conducts continuing education programs.He began in the dental �eld as a laboratory technicianand then became involved in dental materials researchand development. He received his dental degree fromthe University of Southern California. In 1975 he joinedOrmco as director of research and development whilemaintaining a private, general practice. Dr. Swartz receivedhis post-doctoral orthodontic education at the University ofCalifornia, San Francisco. He maintained a private specialtypractice from 1985 to 1998 in Encino, California. He is nowactively lecturing worldwide while treating a limited numberof patients at the Sybron headquarters in Orange, California.

Figure 1.The inspire! bracketprovides a water-clearappearance for thepatient who wantsaesthetic treatment.

Michael L. Swartz, DDS

Encino, California

a history lesson

Gem. Unitek’s original polycrystalline Transcend™

bracket evolved to a mechanical retention base design,the Transcend™ 2000, and then into the Clarity™

design with a metal slot insert.After the merger with “A” Company, Ormco

ceramists and engineers totally redesigned the Star�rebracket based on the lessons from the past, resultingin the inspire!bracket (Figure 1). It has retained thewater-clear attributes of single-crystal sapphire andeliminated the high fracture rate o� ts predecessor.A mechanical retention ball base was added for morereliable bonding and debonding. Ormco’s Face Paint™

was also added for ease in bracket identi�cation andvisibility for accurate bracket placement.

Man-made sapphire is made by drawing a single-crystal mass from ultrapure molten aluminum oxide.The sapphire crystal can measure 4 to 6 inches indiameter and up to 24 inches in height. The crystalhas strong and weak axes. It’s cut into rods along thestronger axis (Figure 2) from which the brackets aresubsequently machined (Figure 3). In the process ofcutting the extremely high-strength single-crystalinto rods and brackets, stress or fracture points arecreated. The machined bracket must then be annealedor heat treated to release these stress points. Experienceand extensive testing have shown that the annealingprocess used for the Star�re bracket was inadequateto remove all the stress points. Star�re brackets wererapidly heated and cooled. The inspire!brackets nowgo through an extensive annealing process thatinvolves three separate cycles in a furnace (Figure 4)at extremely high temperatures for a total period of72 hours (Figures 5 and 6) . The tie-wing dimensionswere also increased to help eliminate fractures. Theoriginal bracket fracture problem appears to havebeen solved. When handled properly, my �rst-handexperience indicates that bracket fractures are now rare.

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INSPIRE! SAPPHIRE BRACKETS

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Figure 2. A crystal sapphire rodis cut to shape in preparation ofmachining brackets.

Figure 3. The bracket slot and tie-wings are machined into the rod(cuspid bracket with hook).

Figure 4. The heat treatment process consists ofthree separate cycles in the furnace at extremelyhigh temperatures for a total of 72 hours. Trayscontaining sapphire brackets are stacked in the furnace (inset).

Figure 6. SEM photographs show the bracket slot before and after heat treatment. Unevenedges become smooth after the annealingprocess in addition to relieving surface �aws.Figure 5. The heat treatment of inspire! brackets involves signi�cantly longer

and slower heating and cooling cycles than the earlier Star�re brackets.

Multiple Factors Contribute to Bonding SuccessThe rhomboid design, mechanical retention ballbase and Face Paint features of inspire!make bond-ing routine and reliable. You can use any bondingmaterial with its mechanical ball base, but I prefer a light-initiated resin system because light-curedmaterials tend to discolor less than self-cured mate-rials. I have been successful in bonding inspire!usingEnlight™ adhesive with a �ve-second exposure fromthe Optilux 501 curing light.

The facial surface of the inspire!bracket is coatedwith Face Paint, a water-soluble dye in a di�erentcolor for each tooth in the arch. Face Paint greatly aidsin visually positioning the bracket during bonding.Immediately after bonding, Face Paint easily rinseso�. The size and rhomboid shape of the bracket isidentical to the popular Diamond™ and Mini Diamond™

brackets so that bracket placement criteria doesn’trequire any change or additional familiarization time.

The inspire!bracket base is coated with a glassbinder on which small, hollow zirconia balls(approximately 40 microns in diameter) are evenlydistributed and fused (Figure 7). The glass binder

Heat Treatment

Duration–One Cycle

Star�re inspire!

Tem

pera

ture

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Figure 7. SEM photographillustrates the mechanicalball base, small zirconiaballs evenly distributed andfused to the bracket base.

Figure 8. SEM photographshows the undercuts createdwhen the zirconia balls andbracket base fuse for the interlock of the bonding resin.

polyurethane) are excellent for ligation with ceramicbrackets but, as we have all experienced, can discolorwith some foods (mustard and curry dishes in particular) and with poor hygiene. Usually, if youremind the patient about what foods to avoid andreinforce good oral hygiene, the ligatures will main-tain an acceptable appearance between visits.

Improved Bonding Base Aids in DebondingRigid ceramic brackets present a debonding challengedi�erent from metal brackets. The more pliable metalbracket assemblies allow easy distortion and safe,atraumatic removal. Earlier ceramic bracket designs,with their chemically bonded bases, resulted inenamel fractures and shattered brackets during thedebonding procedure. The lesson history teaches usis to produce a bonding base design that will routine-ly fail between the bracket base and the bondingmaterial without applying excessive stress to theresin/enamel interface. The solution was developmentof the mechanical ball base design and a specialdebonding plier.

If you compress a ceramic bracket mesiodistallyas you would a pliable metal bracket, it will shatterand can often leave the ceramic bracket base stillattached to the tooth. This procedure leaves you witha di�cult, time-consuming debonding process.

The inspire! debonding method focuses on usinga plastic debonding plier that absorbs and distributesthe forces of debonding such that it causes a bracket/resin interface failure without shattering the bracket.To debond, engage the tips of the inspire!plasticdebonding plier under the incisal/occlusal and gingival tie-wings (Figure 9) and squeeze the plierhandles together �rmly.It is important that the plierhandles are compressed together �rmly and touch beforeany force is exerted to debond(Figure 10). Firmly gripthe bracket with the plier and pivot in either thegingival or occlusal direction in a steady, con�dentmotion until the bracket separates from the bondingresin. The pliers are designed to be used to debondone case, then discard.

melts at a lower temperature than the zirconia balls,fusing them to the aluminum oxide bracket base.This fusion produces �llets where the balls meet thebracket base to create the desired undercuts for theinterlock of the bonding resin (Figure 8) .

Brackets Have Distinct PropertiesOne possible mistake orthodontists made in the pastwas failure to treat ceramic brackets di�erently frommetal brackets. Ceramics are rigid, brittle materials.Rough handling can increase the risk of bracketfracture. Fortunately, we now have titanium wiresthat deliver lower forces than stainless steel, are farkinder to ceramic brackets and can be used through-out treatment. I would certainly encourage the useof nickel titanium, copper nickel-titanium and beta-titanium ( TMA ®) wires with any ceramic brackets.In contrast with the polycrystalline ceramics that aremore opaque, the inspire!brackets are water-clear.While this is aesthetically pleasing, the bracket slotcan be di�cult to see. If you attempt to engage asti�, large rectangular wire in a hard-to-see slot, youcould apply too much force and possibly stress thebracket. By using titanium alloy wires, you can greatlyreduce this risk.

All ceramic brackets are composed of aluminumoxide, which is second in hardness only to diamondand signi�cantly harder than enamel. Placing ceramicbrackets on the lower arch can lead to rapid andsevere enamel wear of the opposing dentition. Whenexplaining the potential risk, I �nd that most patientswill accept metal brackets on the lower arch, partic-ularly when shown that they’ll display little if any ofthe lower brackets during normal speech.

The dimensions of the tie-wing areas of theinspire!bracket have been made comparable to metal(Mini Diamond ) brackets and are easily ligated.The Te�on®-coated steel ligatures seem to be a better,more aesthetic alternative to stainless steel ligaturesand may be more acceptable to the patient whoexperiences discoloration of their clear elastic liga-tures. The elastomeric ligatures (all of which are