TADs versus traditional devices and tecniques in … second molar uprighting procedures ... TADs versus traditional devices and tecniques in ... temporary anchorage ,

Article ID: WMC004494 ISSN 2046-1690

TADs versus traditional devices and tecniques inlower second molar uprighting proceduresPeer review status:No

Corresponding Author:Dr. Francesca Muggiano,Dentist, Dipartimento di Scienze Odontostomatologiche e Maxillo Facciali, Universita' degli Studi di Roma - Italy

Submitting Author:Dr. Francesca Muggiano,Dentist, Dipartimento di Scienze Odontostomatologiche e Maxillo Facciali, Universita' degli Studi di Roma - Italy

Other Authors:Dr. Ivana Giannantoni,Dentist, Dipartimento di Scienze Odontostomatologiche e Maxillo Facciali, Universita degli Studi di Roma - Italy

Dr. Giulia Anastasi,Dentist, Dipartimento di Scienze Odontostomatologiche e Maxillo Facciali, Universita degli Studi di Roma - Italy

Dr. Calicchia Giorgia,Dentist, Dipartimento di Scienze Odontostomatologiche e Maxillo Facciali, Universita degli Studi di Roma - Italy

Dr. Andrea Quaranta,Dentist, Dipartimento di Scienze Odontostomatologiche e Maxillo Facciali, Universita degli Studi di Roma - Italy

Article ID: WMC004494

Article Type: Review articles

Submitted on:04-Jan-2014, 10:58:48 AM GMT Published on: 06-Jan-2014, 04:42:05 AM GMT

Article URL: http://www.webmedcentral.com/article_view/4494

Subject Categories:ORTHODONTICS

Keywords:TADs, temporary anchorage devices, miniscrew, uprighting, disimpaction, second molar, lowersecond molar, impacted, orthodontic devices

How to cite the article:Muggiano F, Giannantoni I, Anastasi G, Giorgia C, Quaranta A. TADs versus traditionaldevices and tecniques in lower second molar uprighting procedures. WebmedCentral ORTHODONTICS2014;5(1):WMC004494

Copyright: This is an open-access article distributed under the terms of the Creative Commons AttributionLicense(CC-BY), which permits unrestricted use, distribution, and reproduction in any medium, provided theoriginal author and source are credited.

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No competing interests.

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TADs versus traditional devices and tecniques inlower second molar uprighting proceduresAuthor(s): Muggiano F, Giannantoni I, Anastasi G, Giorgia C, Quaranta A

Abstract

Impaction of the lower second molar is not a commonproblem. The prevalence of it is low ranging from 0%to 2.3%. The etiology of an impaction is various and itcan involve systemic, local, and periodontal factors, aswell as a developmental disruption of the tooth bud.Treatment options suggested in the literature are varyincluding leaving the tooth in situ,the extractionimpacted second molar, orthodontic uprighting(surgically assisted or not), and autotransplantation. Areview of various traditional and innovative orthodonticdevices and techniques are hence exposed andcompared to help clinicians solve this very challengingcases.

Introduction

Impaction of permanent teeth is a common clinicaloccurrence and may involve any tooth in the dentalarch. The teeth most often impacted, in order offrequency, are the maxillary and mandibular thirdmolars, the maxillary canine, and the mandibularsecond premolar. The impaction of the secondmandibular molar is relatively rare and has a reportedprevalence of 0 % -2.3 % with a male and right sidedpredominance. The most common forms areunilaterally with a mesial, vertical and distal angulation(in descending order), usually associated to severecrowding. In fact, a very complex problem is theuprighting and subsequent eruption of themesioangular impacted lower second or third molar. Inthe normal growth and development of the lower jaw,the molar tooth buds distal to the first permanentmandibular molar have a mesial inclination. Thisinclination is usually self-correcting as the anteriorborder of the mandibular ramus resorbs. Added to this,the mesial drift of the first permanent molar createsapproximately 2.7 mm of space per side for angularadjustment and eruption. When this adjustment doesnot occur, second molar impaction results.

Several orthodontic therapeutic options have beenproposed, priorly the need for third molar extractionshould be evaluated. Frequently, the third molarposition may impede the distal movement of the

impacted molar, indicating the need for extraction.However, from a biomechanical perspective,sometimes it is better to leave the third molar bud tofacilitate the second molar rotation.

Several traditional and innovative orthodontic deviceshave been advanced. The use of miniscrews insecond molars disimpaction represents theculmination of a long period, starting from theseventies until today, has seen a succession of anumber of therapeutic modalities with in order torestore a proper dental occlusion and to reduce thetime of treatment. The choice of which biomechanictechniques is more suitable for each treatment needsis determined by factors such as the severity ofinclusion of the second molar, the accessibility of thecrown of the included tooth, the simplicity and thepossible side effects on dental arch of the chosenmechanism of disimpaction.

Several articles were analyzed with the aim tocompare traditional versus miniscrew biomechanictechnique of second molar disimpaction.

Some of those traditional disimpaction devices used inthe second molar uprighting, as reported in literature,consist in: titanium uprighting coil-springs ( Sander'salike designed uprighting spring), crossed tipbacksprings, orthodontic elastic separating rings, "DeImpactor", Distal jet, complex sectional or segmental,auxiliaries arch- spring techniques, straight wire - TMAwire sequences mechanics combined with surgicaltooth crown exposure and elastic traction or specificwire bending loops. The most often recommendedappliance for molar uprighting and extrusion is asimple tip-back spring, the length of the cantileverdetermines the momento- force ratio, and so theachieved movement. A short cantilever delivers moreextrusion than a longer one.

In Table I are shown the main advantages anddisadvantages associated with the use of traditionalmethods of uprighting.

Possible risks related to the uprighting procedures asreffered by Gazit are:

the issue of the anchor and the side effects on dental●

intra -and inter- arch position;the necessity for a disimpaction device that●

minimizes the risk for dental, bone and adjacentmucosal structures;



correct positioning of the traction rispettoall'elemento●

from disincludere , essential for the properapplication of force and movement of the tooth.

In 2008, Fernandes at al. used a removable retainerdisincludere the second molar, including but not verydeep. The apparatus was constituted by lingual arch,hooks vestibular retention in correspondence of thefirst molars and first premolars, occlusal stops on thefirst molars and a spring uprighting wire realized with0.028 anchored to a composite support polymerizedon the visible surface of the tooth included. Thedisto-buccal cusp of the second molar was surgicallyexposed and an impression was taken of the entirejaw to build the device, the uprighting spring has beenjoined to the composite support and then turned everytwo weeks for 5 months, when it terminated theuprighting of the tooth. Advantages and limitations ofthess proposed equipment are:

- Risks associated with a surgical uprighting arereduced

- Need for a strenuous cooperation from the patient

- The hassle of using fixed equipment (which wouldhave required a continuous bonding of new hooks,following the progress of disimpaction ) is reduced.

Temporary anchorage devices are an alternative totraditional methods of uprighting techniques as ameans to allow second molars uprighting, thuspreventing unwanted dental movements in the sameor opposite arch. It can be said that Branemark havepioneered the experimental work that has establishedthe principle of osseointegration, with the study oftitanium implants and the evaluation of their biological-mechanical characteristics on the insertion site. Withthe succession of numerous studies occurred the wideclinical spread of temporary anchorage devices (TADs), referring to all types of plants treated surface,mini-plates (surgical plates in situ from moreminiscrews) and mini-implants (miniscrews) used fororthodontic anchorage purposes and subsequentlyremoved once exhausted their function. Those devicesare inserted into the bone and the traction of the toothis performed with the aid of springs or elastic chains.Kanomi and Costa have introduced the use ofminiscrews and mini-implants as a means oftemporary anchorage , opening up new frontiers to thepossibilities of orthodontic anchorage;

Table II. Advantages of miniscrews.

The skeletal anchorage , provided by devices such asimplants or mini screws fixed to the bone , it may beindirect (obtained by increasing the reactive supportunit ) or direct ( by fixing the anchorage unit ) bothwere found to be equally successful in 90.5% as

reported by Melo.

Sohn and colleagues described a technique foruprighting using the mini-screw anchorage with anindirect technique: the choice of the indirect anchoravoids some drawbacks related to direct anchor suchas pain referred at the force application site, thereduced effectiveness of the applied mechanism whenthe force vector intensity is reduced and the lack ofutility in the upper jaw .

In contrast Lee et al. have promoted the use ofminiscrew as direct anchorage changing the miniimplant position in order to obtain two different types offorce. The miniscrew can be positioned in theretromolar area, where it acts as a fulcrum for thetraction by pulling distally to the second molar, ormesially to the same element where is the point ofapplication of a tension force. It is important to knowthis dual possibility of use mini implant in molaruprighting taken in account the fact that the center ofrotation of the second molar lies in the bifurcation ofthe roots of this tooth. In fact, in mild inclusion caseswith mesial inclination of the crown, placing the miniimplant in the retromolar area, it is possible togenerate an effective uprighting sufficient to allow thecomplete straightening of the molar. Instead inmoderate to severe inclusion cases, the generatedmoment is too small to produce a sufficientstraightening of the tooth. For this reason it is essentialto consider the possibility of placing the mini implantmesially to the included tooth so as a thrusting actionforce from mesial to distal in generated. The distalizingaction force is due to an open -coil spring , replacedevery 4 weeks. The third molar bud extraction isoptional and required only if its contiguity is anobstacle to the eruptive course of the second molar.

Musilli et al. proposed three different methods of usingmini screws for molar uprighting:

1 . To place mini screw in the retromolar area andapply an elastic chain loaded between the screw andthe molar;

2 . To place a screw in the retromolar area and use asmall cantilever active when intrusion and uprighting isperformed;

3 . To use a miniscrew placed a few millimeters mesialto the molar for controlling the vertical force producedby the long frontal teeth-uprighting tooth cantilever.

Discussion

The prevalence of impacted second molars is low,ranging from 0% to 2.3 % . The etiology of impaction



can involve systemic, local and periodontal factors, aswell as a developmental disruption of the dental buds.Several surgical and orthodontic treatment optionshave been suggested in literature as leaving the toothin situ, removing it, orthodontic uprighting andautotransplantation of dental buds. Tooth impactionprecludes its complete eruption and requires a properuprighting treatment. Temporary Anchorage Devicesallow disimpaction and the achievement of their finalposition , without the movement and reaction forces onother dental elements or the patient's compliance.

Therefore it is clear that the anchorage control is oneof the most important aspects of orthodontic treatment:in fact, success depends on the protocol anchoragedifferently planned for each single case. Theintroduction of mini- implants in orthodontics hassolved the problem of patient's cooperation andensure a safe and stable anchorage .

In conclusion, the use of miniscrews presents thefollowing advantages :

ease of use;●

lack of cooperation by the patient;●

reduced duration of treatment;●

good control of dental movements;●

requires the use of only a miniscrew or a bracket /●

button on the tooth surface, minimizing thediscomfort of the patient;the insertion of the implant and the application of●

force can be effected in a single session (unlikeconventional treatments that require taking theimpression and a laboratory phase);

Furthermore, the supporters of the techniques of directanchoring, highlight the simplicity of application of theforces compared to indirect anchorage, thuseliminating the possibility of any undesirablemovement on anchoring teeth;

If the implant is inserted in the premolar area isreduced the need for third molar extraction.

In relation to third molars presence, Melsen andcolleagues demonstrated that the third molarextraction can change the center of resistance of thesecond molar, inducing unwanted movement in thedistal direction. In fact, in a computer simulation , itwas revealed a significant mesial movement of theroots and a distal tip -back of the crown. However, thethird molar bud presence can hinder the second molaruprighting movement, thus causing unwantedmovement in the anchoring segment .

Finally, it is necessary to highlight some limitations inthe use of miniscrews :

– In lingually inclined or rotated molars, the applicationof a single force may be insufficient to complete the

straightening of the tooth , making necessary theapplication of different and more complex biomechanicsystems of forces;

– The uprighting movement must always be carefullycontrolled to avoid unwanted movements on thebuccal or lingual side;

– Miniscrew can not be used in extruded dentalelements , because the system of forces necessary inthis case is rather complex to apply. In these situationsit may be more convenient the choice of traditionalmethods such as the application of an V arc or of aSander's uprighting spring.

Conclusions

Second molar impaction is a very challengingtherapeutic treatment issue. A proper clinical,radiological, and biomechanical evaluation and athoughtful selection of the best orthodontic devices toapply and treatment mechanics, encompassingdifferent levels of complexity, based on each singlecase features is necessary to grant successfultreatment results.

References

1. Varpio M, Wellfelt B. Disturbed eruption of the lowersecond molar: clinical appearance, prevalence, andetiology. ASDC J Dent Child. 1988;55:114-8.2. Cassetta F, Altieri F, Di Mambro A, Galluccio G,Barbato E. Impaction of permanent mandibular secondmolar: a rerospective study. Med Oral Patol Oral CirBucal. 2013 Jul;18(4).3. Gazit E, Lieberman M. A mesially impactedmandibular second molar. Treatment considerationsand outcome: a case report. Am J Orthod DentofacialOrthop. 1993 Apr;103(4):374-6.4. Fernandes AF, Fernandes DJ, Quintao C, MendesA. Uprighting an impacted second molar with a springanchored to a composite support. J Clin Orthod. 2008May;42(5):301-2.5. Aksoy AU, Aras S. Use of nickel titanium coilsprings for partially impacted second molars. J ClinOrthod. 1998 Aug;32(8):479-826. Kanomi R. Mini-implant for orthodontic anchorage. JClin Orthod. 1997 Nov;31(11):763-77. Saito CT, Pereira AL, Varanda T, Panzarini SR,Bernabe PF, de Mendonca MR. Uprighting impactedmandibular second molars with orthodontic elasticseparat ing r ings. Quintessence Int . 2009May;40(5):359-618. Papadopoulos MA, Tarawneh F. The use of



miniscrew implants for temporary skeletal anchoragein orthodontics: a comprehensive review. Oral SurgOral Med Oral Pathol Oral Radiol Endod. 2007Feb:e6-e15.9. Lau CK, Whang CZ, Bister D. Orthodonticuprighting of severly impacted mandibular secondmolars. Am J Orthod Dentofacial Orthop. 2013Jan;143(1):116-24.10. Melo AC, Duarte de Silva R, Shimizu RH, CamposD, Andrighetto AR. Lower molar uprighting withminiscrew anchorage: direct and indirect anchorage.Int J Orthod Milwaukee 2013 Fall;24(3):11. Sohn BW, Choi JH, Jung SN, Lim KS. Uprightingmesially impacted second molars with miniscrewanchorage. J Clin Orthod. 2007 Feb;41(2):94-7; quiz72.12.Lee KJ, Park YC, Hwang WS, Seong EH.Uprighting mandibular second molars with directminiscrew anchorage. J Clin Orthod. 2007Oct;41(10):627-35.13. Musilli M, Marsico M, Romanucci A, Grampone F.Molar uprighting with miniscrew: comparison amongdifferent systems and relative biomechanical analysis.Prog Orthod 2010;11(2):166-173.14. Luzi C, Luzi V,MelsenB. Mini-implants and theefficiency of Herbst treatment: a preliminary study.Prog Orthod. 2013 Jul 31;14(1) :21. do i :10.1186/2196-1042-14-21.15. Carano A, Testa M, Siciliani G. The Distal Jet foruprighting lower molars. J Clin Orthod. 1996Dec;30(12):707-10.



Advantages Disadvantages

Simplicity of use Necessity of having the entire dental archbanded in order to get the proper anchor forcesand biomechanism

Reducing the possible traumatism of theincluded tooth

Possible soft tissue irritation

Deformation or fracture of the spring

Illustrations

Illustration 1

Table 1: Advantages and disadvantages of the traditional methods of uprighting.



ADVANTAGES OFMINISCREWS

Excellent mechanical retention

The primary stability offered by miniscrew allows immediate loadingwith a light force and continues , more often developed with the use ofnickel-titanium springs or elastic chains

The retromolar mini implant positioning in the disimpaction of secondlower molars also offers significant biomechanical advantages given theproximity between the fulcrum of application and the center of resistanceof the molar , facilitating the vertical control during the extrusion phase .

The use of springs in the nickel-titanium offers additional benefits suchas the necessity of a smaller number of activation , therefore reducing thepatient's discomfort and chair time, and the frequency of appointments.

Surgical procedures for mini implant's placement is well tolerated bypatients with also a reduced risk of site infection

Illustration 2

Table 2: Advantages of miniscrews


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TADs versus traditional devices and tecniques in … second molar uprighting procedures ... TADs versus traditional devices and tecniques in ... temporary anchorage ,