Reliability of digital orthodontic setups

Originl Article Relibility of digitl orthodontic setups Monic S. Brreto ; Jorge Fber b ; Crlos J. Vogel c ; Telm M. Arujo d ABSTRACT Objective: To evlute the relibility of digitl orthodontic setup technology by compring it with mnul setups nd models cst t the end of orthodontic tretment. Mterils nd Methods: Initil models, mnul setups, nd finl models of 20 ptients were used. The initil nd finl models, s well s the mnul setups, were scnned using 3Shpe R-700 scnner, while the digitl setups were fbricted bsed on the initil models using 3Shpe OrthoAnlyzer softwre. Evlution of the models bsed on the mnul setup, digitl setup, nd finl models of ech ptient ws performed using the following liner mesurements: intercnine widths, intermolr widths, nd length of the upper nd lower dentl rches. Results: The results disclosed tht none of the mesures ssessed through the mnul setup, digitl setup, nd finl models showed sttisticlly significnt differences (P..05). Conclusions: Bsed on these findings, it cn be inferred tht digitl setups re s effective nd ccurte s mnul setups nd constitute tool for dignosing nd tretment plnning tht cn be relibly reproduced in orthodontic tretments. (Angle Orthod. 0000;00:000 000.) KEY WORDS: Computer-ssisted dignosis; Dentl models; Three-dimensionl imging INTRODUCTION Setup is technique whereby teeth re ressembled in plster models to depict the ptient s mlocclusion. 1 6 In crrying out this dignosis, the teeth re seprted from ech other nd from the bses of upper nd lower csts, llowing them to be repositioned within the frmework of orthodontic tretment plnning. 1 4 Setup s key dvntge lies in llowing professionls to scertin tht tretment plnning is indeed vible in ech cse. 1,3,5,6 It nswers questions such s the following: Are extrctions necessry or will the mere stripping of interproximl prove sufficient to lign the teeth? How much interproximl stripping should be performed nd Resident in Orthodontics, Deprtment of Orthodontics, Federl University of Bhi, Slvdor, Brzil. b Adjunct Professor, Postgrdute Progrm in Helth Sciences, Deprtment of Orthodontics, University of Brsili, Brsili, Brzil. c Visiting Professor, Deprtment of Orthodontics, Federl University of Bhi, Slvdor, Brzil. d Chir, Deprtment of Orthodontics, Federl University of Bhi, Slvdor, Brzil. Corresponding uthor: Dr Monic S. Brreto, Av Arujo Pinho, 399, Apt 1302, Cnel, Slvdor BA 40110-150, Brzil (e-mil: monicsbrreto@hotmil.com) Accepted: April 2015. Submitted: December 2014. Published Online: June 4, 2015 G 0000 by The EH Angle Eduction nd Reserch Foundtion, Inc. on which teeth? Wht precutions would be necessry to ensure proper nchorge? Fbriction of mnul setup involves lborious technique. However, when properly performed nd nlyzed, it provides dt tht cn fcilitte tretment nd reduce biologicl dmge to the ptient. 4 Therpy should be initited only fter mking sure tht plnning is suitble for correcting given mlocclusion. 4,6 With the incresing use of digitl dentl models, it is now possible to build digitl orthodontic setups. These llow one to review different orthodontic tretment options tht cn be shred with other orthodontists nd helth-relted professionls to exchnge informtion bout the tretment. Furthermore, digitl setups lso mke it esier to present the therpeutic lterntives to ptients nd/or their legl gurdins, llowing them to understnd the best tretment option. 6 8 Given the emergence of new softwre, this study imed to evlute the relibility of digitl orthodontic setup technology by compring it with mnul setups nd with the finl tretment models. For this purpose, OrthoAnlyzer (3Shpe, Copenhgen, Denmrk) computer softwre ws employed. MATERIALS AND METHODS The smple size (n) consisted of 20 ptients. Clcultion ws performed using n expected difference of 1, with 80% power nd n 5% lph level. Smple size clcultion ws performed using BioEstt DOI: 10.2319/120914-890.1 1

2 BARRETO, FABER, VOGEL, ARAUJO softwre (version 5.0, Mmiruá Institute, Belém, Prá Stte, Brzil). Ethicl pprovl for this study ws obtined from the Ethicl Coittee of the Federl University of Bhi, Fculty of Dentistry. To be selected, ptients hd to meet the following criteri: orthodontic tretment must hve been completed, presence of permnent teeth s fr s the second molrs, tretment must not involve prosthetic rehbilittion, fcil growth must hve been completed before the strt of tretment, no involvement of orthognthic surgery, dentl csts properly fbricted 2 nd in perfect condition, nd mnul setups bsed on the proposed tretment pln. Mnul setups, digitl setups, nd finl models of the ptients were used in the study. To fbricte the setups, the uthors endevored to comply with the key principles of norml occlusion by preserving the originl intermolr nd intercnine widths, mintining the rch form, ttining correct contct points, norml overbite nd overjet, coincident nd correct midlines, correct xil inclintions nd ngultions (tip), no rottions, norml reltionship between occlusl inclined plnes, nd pproprite curve of Spee nd curve of Wilson. To produce the digitl models, n R-700 scnner (3Shpe) ws used, which fetures lser bem nd two digitl cmers cpble of cpturing high-resolution imges. The sme specilist in orthodontics scnned the models ccording to the specifictions provided by the equipment mnufcturer. The initil models, finl models, nd mnul setups were scnned. The mnul setups hd been previously fbricted by grdute students from the Speciliztion Progrm in Orthodontics, Federl University of Bhi, ccording to the tretment pln proposed under the supervision of n orthodontics instructor following the method described by Arújo et l. 2 The mnul setups were mde nd used for dignosis nd plnning prior to the orthodontic tretment. In scnning the mnul setups, the sme technique ws used for initil models. However, given tht wx where the teeth re mounted is not scnned by the lser, Spotcheck SKD-S2 (Mgnflux, Glenview, Ill) solvent developer hd to be used on the wx re. The finl models were scnned without the use of developer. The digitl setups were constructed bsed on the initil models scnned using the OrthoAnlyzer (3Shpe) softwre. The resercher who built the digitl setup hd ccess to the tretment pln, exmintions, nd initil models. However, he ws blinded to the mnul setup nd finl model. The setup ws bsed on the nchorge requirements, the finl desired position for the whole mxill nd mndible ccording to the tretment pln, the expected torque Figure 1. (A) Mxillry model preprtion process. (B) Imge depicting teeth mnipultion. loss relted to wire ply nd other fctors, the mount of overcorrection for rottion control, nd the rch forms. Initilly, the upper nd lower rch forms were obtined nd the crown xis determined. The teeth were sectioned one by one, preserving the ntomy of the tooth crown in the mesiodistl nd buccolingul directions (Figure 1A), while ensuring tht ech section extended right through the contct point. After this stge, mnul djustment of individul teeth to their idel positions ws performed ccording to the tretment pln. The mounting ws initited by repositioning the lower incisors. One side ws mounted t time, nd the rch form ws mintined. Finlly, the models in occlusion were evluted for potentil collisions between the teeth, nd when necessry, corrections were mde (Figure 1B). When redy, the digitl setups were sved s digitl models, nd no further chnges were llowed

RELIABILITY OF DIGITAL ORTHODONTIC SETUPS 3 Tble 1. Results of Intrclss Correltion (ICC) Between Mesurements Mesurement ICC Conclusion P Upper ICW.62 Fir reproducibility,.001 Outstnding reproducibility,.001 IMW.8 Outstnding reproducibility,.001 LDA.93 Lower ICW.75 Outstnding reproducibility,.001 IMW.76 Outstnding reproducibility,.001 LDA.93 Outstnding reproducibility,.001 ICW indictes intercnine widths; IMW, intermolr widths; LDA, length of the dentl rches. Sttisticl Anlysis Sttisticl nlysis ws performed with BioEstt softwre (version 5.0, Mmiruá Institute, Belém, Prá Stte, Brzil). D Agostino-Person test ws employed to observe norml dt distribution. Moreover, repeted-mesures nlysis of vrince (ANOVA) nd Friedmn test were used to test the null hypothesis of no difference between the mesurements of the setup methods nd finl models of the ptients. The significnce level ws set t 5%. Figure 2. (A) Intercnine nd intermolr widths of the mxillry rch. (B) Length of the mndibulr rch. to be mde in tooth positions to ensure relible mesurements. Comprisons between digitl models in terms of mnul setup, digitl setup, nd finl model were crried out by mens of liner mesurements: intercnine nd intermolr widths nd length of the upper nd lower dentl rch (Figure 2). The mesurements were performed by properly clibrted exminer with the id of OrthoAnlyzer softwre (3Shpe). Prior to mesuring, five ptients were rndomly selected. The digitl mesurements were performed t two different points in time with 2-week intervls between them, under the sme conditions, by single duly trined opertor. The mesured vlues were subjected to sttisticl test to determine rndom error. For ll vribles, rndom error ws clculted ccording to Dhlberg s formul (S 2 5 Sd 2 /2n) to verify intrexminer greement. Anlysis of the reproducibility of mesurements ws performed by testing intrclss correltion, with confidence level of 95%. RESULTS Method error clcultion took into ccount relible mesurements given their remrkble reproducibility potentil. Correltions for most mesurements were rted s outstnding (r 5.75 to.93), wheres in evluting the intercnine width in the upper rch, there ws sttisticlly significnt correltion (P,.001), which ws given positive rting (r 5.62; Tble 1). In nlyzing the dt, the Friedmn test ws used to ssess the length of the upper rch in the mnul setup, digitl setup, nd finl model. Likewise, the sme test ws pplied to evlute the intercnine width in the lower rch of the mnul setup. An ANOVA ws used to ssess the remining mesures. Descriptive sttistics nd results re shown in Tble 2. None of the mesures ssessed with the id of the mnul setup, digitl setup, nd finl models showed ny sttisticlly significnt differences (P..05). DISCUSSION Studies on virtul setup relibility re still scnt in the literture, nd this contrsts with the incresing sophistiction nd investment in the development of these tools. In using the setup, the min gol is to provide the orthodontist with relistic view of how

4 BARRETO, FABER, VOGEL, ARAUJO Tble 2. Dentl Arches Upper Descriptive Sttistics nd Results of Friedmn nd Anlysis of Vrince Tests for Mnul Setups, Digitl Setups, nd Finl Models Menu/Medin, Model Mnul Setup Digitl Setup Finl Model Menu/Medin, Menu/Medin, ICW 34.50u 1.38 + 34.82u 1.72 + 35.06u 1.57 +.5301 IMW 49.79u 2.68 + 49.51u 2.17 + 49.24u 2.16 +.7678 LDA 30.25 28.05 39.15 b 30.35 27.68 39.56 b 32.00 29.11 40.12 b.0578 Lower ICW 27.11 26.56 28.41 b 27.33 23.56 28.52 b 27.23 23.96 29.30 b.256 IMW 43.12u 2.61 + 42.84u 1.97 + 42.80u 2.16 +.888 LDA 29.24u 3.45 + 28.88u 3.72 + 29.48u 3.49 +.8681 ICW indictes intercnine widths; IMW, intermolr widths; LDA, length of the dentl rches. b Friedmn test ws used to ssess these mesures. u represents the men vlue;, the medin vlue; + the stndrd devition vlue. Devition + / P cse tht is being plnned will likely end, no mtter if the setup is physicl or digitl. Thus, the setup should not be constructed rtisticlly to help persude the ptient to ccept tretment but very crefully, in line with the tretment gols nd limittions of orthodontic mechnics. 2 In the study, the digitl models were lso nlyzed by converting the mnul setup nd finl model into digitl models. According to Sous et l., 4 the digitl models proved s relible s plster models (csts) in obtining the mesures coonly used for dignosis. Fleming et l. 5 reported tht digitl models offer high degree of vlidity when compred with the direct mesurement of plster models, nd the differences between these pproches re likely to be within cliniclly cceptble limits. However, there my be smll differences between mesurements mde on plster models vs digitl models. Therefore, to obtin more ccurte results nd to void confusion cused by model nlysis methods, models were nlyzed by converting mnul setups into digitl models. The results indicted tht mnul setups re relible tools for plnning tretment. This is becuse there re no differences in the mesurements performed in the finl models vs the mnul setups, thus confirming the results found by Im et l. 9 As result, this lck of differences between the mnul nd digitl setups suggests tht the digitl setups llow one to envision the tretment gols in mnner similr to mnul setups. Digitl setups seem to offer dvntges over mnul setups. Initilly, the progrm is esy to lern nd mnipulte. In ddition, imge setups re esy to store s they do not require lrge physicl spces, s is the cse with plster models, whose storge costs re extremely costly in mny cities round the world. Finlly, couniction between professionls nd the ptient is fcilitted, since setups cn be sent over the Internet, voiding potentil brekge during shipping nd hndling. This dvntge is lso mentioned by some uthors regrding digitl models. 10 17 In recent yers, replcing conventionl dignostic methods with other more technologiclly dvnced methods hs become coon in the medicl nd dentl res. 18,19 The use of digitl setups seems to hve the potentil to reinforce this trend, which could men further development in the process of storing informtion required for orthodontic dignosis. In this study, the progrm used to perform the digitl setup provided poor visuliztion of the gum line. The gum does not follow extensive tooth movements, which hinders gum line nlysis. Arújo et l. 2 emphsized the vrious disdvntges of mnul setups, including lengthy fbriction time given tht professionls spend few hours doing lbortory work, lthough this fctor does not preclude its use. This ssertion proves even more flexible when the digitl setup is used s n id in orthodontic dignosis. Although this investigtion did not evlute the time it tkes to construct model, it ws found tht the time tken to construct digitl setup from scnning of the initil model to completion ws 2 hours. On the other hnd, prepring the mnul setup directly on the plster models involves cutting, prepring the teeth nd model bses, nd mounting the plnned occlusion, nd it tkes much longer. The results of this study demonstrte tht the use of digitl orthodontic setups is relible nd n excellent method of orthodontic tretment, s it llows threedimensionl view of the ptient s occlusion t the end of tretment. This enbles greter confidence in the ppliction of ny orthodontic therpy. A comprison between the setups nd the finl model in this study

RELIABILITY OF DIGITAL ORTHODONTIC SETUPS 5 ressures orthodontists with respect to the use of setups, both mnul nd digitl, s tool to determine the orthodontic therpy of choice. Nevertheless, further studies re wrrnted to ssess the relibility of virtul setups nd to develop lgorithms to predict gingivl response to tooth movement, which would llow further refinement of orthodontic plnning. CONCLUSION N Bsed on these findings, it cn be inferred tht digitl setups re s effective nd ccurte s mnul setups nd consist of tool for dignosis nd tretment plnning tht cn be relibly reproduced in orthodontic tretments. ACKNOWLEDGMENT We thnk Dr Dvid Normndo for ssistnce with the sttisticl nlysis. REFERENCES 1. Kim SH, Prk YG. Esy wx setup technique for orthodontic dignosis. J Clin Orthod. 2000;34:140 144. 2. Arújo TM, Fonsec LM, Clds LD, Cost-Pinto RA. Preprtion nd evlution of orthodontic setup. Dentl Press J Orthod. 2012;17:146 165. 3. Mttos CT, Gomes AC, Ribeiro AA, Nojim LI, Nojim M d C. The importnce of the dignostic setup in the orthodontic tretment pln. Int J Orthod. 2012;23:35 39. 4. Sous MV, Vsconcelos EC, Jnson G, Grib D, Pinzn A. Accurcy nd reproducibility of 3-dimensionl digitl model mesurements. Am J Orthod Dentofcil Orthop. 2012;142: 269 273. 5. Fleming PS, Mrinho V, Johl A. Orthodontic mesurements on digitl study models compred with plster models: systemtic review. Orthod Crniofc Res. 2011;14:1 16. 6. Mrcel T. Three-dimensionl on-screen virtul models. Am J Orthod Dentofcil Orthop. 2001;119:666 668. 7. Sntoro M, Glkin S, Teredesi M, Nicoly OF, Cngilosi TJ. Comprison of mesurements mde on digitl nd plster models. Am J Orthod Dentofcil Orthop. 2003;124:101 105. 8. Quimby ML, Vig KWL, Rshid RG, Firestone AR. The ccurcy nd relibility of mesurements mde on computerbsed digitl models. Angle Orthod. 2004;74:298 303. 9. Im J, Ch JY, Lee KJ, Yu HS, Hwng CJ. Comprison of virtul nd mnul tooth setups with digitl nd plster models in extrction cses. Am J Orthod Dentofcil Orthop. 2014;145:434 442. 10. Plmer NG, Ycyshyn JR, Northcott HC, Nebbe B, Mjor PW. Perceptions nd ttitudes of Cndin orthodontists regrding digitl nd electronic technology. Am J Orthod Dentofcil Orthop. 2005;128:163 167. 11. Rheude B, Sdowskyb PL, Ferrierc A, Jcobsond A. An evlution of the use of digitl study models in orthodontic dignosis nd tretment plnning. Angle Orthod. 2005;75: 300 304. 12. Myers M, Firestone AR, Rshid R, Vig KW. Comprison of peer ssessment rting (PAR) index scores of plster nd computer-bsed digitl models. Am J Orthod Dentofcil Orthop. 2005;128:431 434. 13. Okunmi TR, Kusnoto B, Begole E, Evns CA, Sdowsky C, Fdvif S. Assessing the Americn Bord of Orthodontics objective grding system: digitl vs plster dentl csts. Am J Orthod Dentofcil Orthop. 2007; 131:51 56. 14. Horton HM, Miller JR, Gillrd PR, Lrson BE. Technique comprison for efficient orthodontic tooth mesurements using digitl models. Angle Orthod. 2010;80:254 261. 15. Noh H, Nbh W, Cho J, Hwng H. Registrtion ccurcy in the integrtion of lser-scnned dentl imges into mxillofcil cone-bem computed tomogrphy imges. Am J Orthod Dentofcil Orthop. 2011;140:585 591. 16. Slj M, Splj S, Jelusic D, Slj M. Discriminnt fctor nlysis of dentl rch dimensions with 3-dimensionl virtul models. Am J Orthod Dentofcil Orthop. 2011;140: 680 687. 17. Dnz JC, Ktsros C. Three-dimensionl portble document formt: simple wy to present 3-dimensionl dt in n electronic publiction. Am J Orthod Dentofcil Orthop. 2011;140:274 276. 18. Abdelkrim A. Myths nd fcts of cone bem computed tomogrphy in orthodontics. J World Fed Orthod. 2012;1: e3 e8. 19. Abdelkrim A. A cone bem CT evlution of orophryngel irwy spce nd its reltionship to mndibulr position nd dentocrniofcil morphology. J World Fed Orthod. 2012;1: e55 e59.