Originl Article Three-dimensionl positionl ssessment of glenoid fosse nd mndibulr condyles in ptients with Clss II subdivision mlocclusion Julin Mcêdo de Mttos ; Jun Mrtin Plomo b ; Antonio Crlos de Oliveir Ruells c ; Pul Loureiro Cheib d ; Mnhl Eliliwi e ; Bernrdo Quirog Souki f ABSTRACT Objectives: To test the null hypotheses tht the positions of the glenoid fosse nd mndibulr condyles re identicl on the Clss I nd Clss II sides of ptients with Clss II subdivision mlocclusion. Mterils nd Methods: Retrospective three-dimensionl (3D) ssessments of the positions of the glenoid fosse nd mndibulr condyles were mde in ptients with Clss II mlocclusion. Reltive to fiducil reference t the nterior crnil bse, distnces from the glenoid fosse nd condyles were clculted in pretretment cone bem computed tomogrphic scns of 82 ptients: 41 with Clss II nd 41 with Clss II subdivision mlocclusions. The 3D distnces from glenoid fosse to sell turcic in the X (right-left), Y (nterior-posterior), Z (inferior-superior) projections were clculted. Results: Ptients with Clss II mlocclusion displyed symmetric position of the glenoid fosse nd condyles with no sttisticlly significnt differences between sides (P..05), wheres ptients with Clss II subdivision showed symmetry in the distnce between the glenoid fosse nd nterior crnil bse or sell turcic (P,.05), with distlly nd lterlly positioned glenoid fosse on the Clss II side. (P,.05). Mle ptients hd greter distnces between glenoid fosse nd nterior crnil fosse (P,.05). The condylr position reltive to the glenoid fosse did not differ between the two mlocclusion groups nor between mles nd femles (P..05). Conclusions: The null hypotheses were rejected. Ptients with Clss II subdivision mlocclusion displyed symmetriclly positioned right- nd left-side glenoid fosse, with distlly nd lterlly positioned Clss II side, lthough the condyles were symmetriclly positioned within the glenoid fosse. (Angle Orthod. 2017;87:847 854.) KEY WORDS: Angle Clss II mlocclusion; Temporomndibulr joint; Clss II subdivision Former Resident, Grdute Progrm in Orthodontics, Pontificl Ctholic University of Mins Geris, Belo Horizonte, Brzil. b Professor nd Residency Director, Deprtment of Orthodontics, nd Director of the Crniofcil Imging Center, Cse Western Reserve University, Clevelnd, OH, USA. c Associte Professor, Deprtment of Orthodontics, Federl University of Rio de Jneiro, Rio de Jneiro, Brzil. d PhD Student, Grdute Progrm in Orthodontics, Pontificl Ctholic University of Mins Geris, Belo Horizonte, Brzil. e Reserch Fellow, Deprtment of Orthodontics, Cse Western Reserve University, Clevelnd, OH, USA. f Associte Professor, Deprtment of Orthodontics, Grdute Progrm in Orthodontics, Pontificl Ctholic University of Mins Geris, Belo Horizonte, Brzil. Corresponding Author: Dr Bernrdo Quirog Souki, Deprtmento de Ortodonti, Pontifíci Universidde Ctólic, Av. Dom José Gspr, 500 Prédio 46, Sl 106, Belo Horizonte, Mins Geris 30535-901, Brzil (e-mil: souki.bhe@terr.com.br) Accepted: July 2017. Submitted: December 2016. Published Online: September 1, 2017 INTRODUCTION The distl positions of the glenoid foss reltive to the crnil bse nd of condyles in glenoid fosse hve been ssocited with the etiology of Clss II mlocclusion. 1,2 However, in symmetric cses such s those of Clss II subdivision, it remins uncler how the temporomndibulr joint s (TMJ) ntomic position influences the occlusl pttern. Erly investigtions into the dentoskeletl components of Clss II subdivision, typiclly bsed on two-dimensionl (2D) imges, detected no ssocition between cliniclly visulized occlusl symmetry nd skeletl bnormlities. 3 6 Accordingly, dentolveolr chnges were ssocited with the etiology of Clss II subdivision mlocclusion; Ó 2017 by The EH Angle Eduction nd Reserch Foundtion, Inc. DOI: 10.2319/121216-890.1 847
848 DE MATTOS, PALOMO, DE OLIVEIRA RUELLAS, CHEIB, ELILIWI, SOUKI however, despite their historic importnce, 2D exms hve inherent limittions of relibility. 7,8 Reserch hs shown tht to evlute fcil skeletl symmetries, three-dimensionl (3D) imging is mndtory. 9 Indeed, with the incresed use of cone bem computed tomogrphy (CBCT), studies hve found results contrsting those of previous 2D investigtions. Recent 3D evidence hs shown tht Clss II subdivision mlocclusion might be ssocited not only with symmetric occlusl pttern but lso with skeletl components, 9 11 nd 3D studies show gret potentil to id in the visuliztion of the skull nd TMJ structures. 9 12 Minich et l. 10 compred Clss II subdivision ptients with Clss I controls, nd lthough they found significnt skeletl nd occlusl differences between the groups, dentl components contributed to twothirds of ll symmetry. Li et l., 11 who lso compred Clss II subdivision nd Clss I mlocclusions, showed tht symmetric ptterns contributed mjorly to the distl positioning of glenoid fosse. Given the chllenge of treting Clss II subdivision ptients, primrily becuse the dignosis of symmetry is frequently difficult bsed on clinicl exmintion lone, studies tht cn provide clinicins with epidemiologicl dt bout the components of Clss II subdivision re necessry. However, previous reports on the topic remin contrdictory, nd evidence bout chnges in the position of glenoid fosse is lcking. At present, the literture lso revels gp in the comprison between Clss II subdivision nd Clss II ptients themselves. Improvements in the dignosis of the position nd morphology of TMJ structures cn help chieve more ccurte orthodontic dignoses nd increse the effectiveness of tretment. 2,10,13 Therefore, the im of this retrospective CBCT investigtion ws to evlute ptients with Clss II subdivision nd skeletl Clss II mlocclusion with mndibulr deficiencies bsed on fcil nlysis. The null hypothesis ws tht the position of glenoid fosse nd condyles is identicl between the Clss I nd II sides of ptients with Clss II subdivision. MATERIALS AND METHODS The Institutionl Review Bord t the Pontificl Ctholic University of Mins Geris pproved this retrospective study bsed on pretretment orthodontic records. Bsed on the stndrd devition of 2.149 mm reported by Li et l. 11 for the primry outcome of the current reserch (ie, sgittl position of the glenoid foss), n lph significnce level of 0.05 nd power of 0.80 to detect differences between groups greter thn 1.3 mm, smple size of 41 ptients per group ws dopted. The smple consisted of 82 orthodontic ptients (49 mle nd 33 femle), ll ged 12 to 17 yers. A totl of 41 ptients presented with Clss II subdivision mlocclusion (C2SD), nd 41 with Angle Clss II mlocclusion (C2). Inclusion criteri were permnent dentition, presence of Clss II subdivision mlocclusion (ie, in the C2SD group), or Angle Clss II (ie, in the C2 group), nd the vilbility of CBCT scns t the beginning of orthodontic tretment. Ptients with syndromes, dentofcil deformities, temporomndibulr disorders, or histories of orthodontic tretment were excluded. All C2SD ptients nd 19 of the C2 ptients hd CBCT performed s component of pretretment records t Cse Western Reserve University, Clevelnd, Ohio (CB MercuRy, Hitchi Medicl Systems Americ Co., Twinsburg, Ohio), nd 22 C2 ptients hd CBCT scns cquired s prt of the pretretment routine of orthodontic record tking t Pontificl Ctholic University of Mins Geris, Belo Horizonte, Brzil (i-cat, Imging Sciences Interntionl, Hrtfield, P). Imges with the CB MercuRy were tken with field of view of 20.3 cm, 0.37 mm voxel size, nd custom settings of 2mA, 120 kvp, nd 9.5-second exposure. The i-cat imges were tken with field of view of 17 3 22 cm, 0.3 mm voxel dimension, 5mA, 120 kv, nd 40 seconds of exposure. All ptients were instructed to bite into mximum intercusption during scn cpture. Mesurement Tomogrphic imges were processed using Dolphin Imging softwre version 11.7 (Dolphin Imging & Mngement Solutions, Chtsworth, Clif). Before mesurements, ptients heds were oriented long three plnes of spce so tht mesurements could be tken with ll ptients in the sme position ccording to previously reported criteri. 14 Angulr nd liner mesurements were ssessed using voxel dimension of 1 mm to ensure better shrpness nd stndrdiztion. From the topogrphic sgittl view, modifiction of the fiduciry crnil bse reference point of the fronto-mxillo-nsl (FMN) suture, locted s described for 2D cephlometry, 2,15 ws selected for mesuring the sptil reltionships of the TMJ. From the sgittl view of the FMN point, verticl reference line ws drwn tht, from 3D perspective, defined the coronl plne tngent to the FMN point dubbed the stble plne (Figure 1). The selection of the stndrdized xil cross-section ws bsed on the first section of the mndibulr condyle, from top to bottom, which included the lrgest medil lterl condylr mesurement. Cross-sections were selected independently for the left nd right sides
FOSSA AND CONDYLE POSITION IN CLASS II SUBDIVISION 849 Figure 1. Identifiction of the stble plne (SP). A verticl dshed line tngent to the front mxillo nsl point is drwn. In threedimensionl perspective, the coronl plne is tngent to SP. The stright line is the xil plne perpendiculr to the SP. (Figure 2). In the xil sections, three lndmrks (P1, P2, nd C) were mrked. P1 ws locted in the most nterior internl contour of the glenoid foss nterior wll; P2 ws locted in the most posterior internl contour of the glenoid foss posterior wll; nd C ws the geometric center of the condyle. From the three lndmrks, orthogonl liner mesurements were tken reltive to the stble plne nd mid-sgittl line (MSL), both on the right nd left sides of ll ptients. From the xil view, the coronl plne ws positioned tngentilly to the geometric center of the right nd left condyles. From coronl views, the ngulr inclintions of the right nd left glenoid fosse (A1) were clculted using the line constructed from the most medil nd lterl poles of the fosse wlls nd the xil plne tngentilly to the most superior spect of the glenoid fosse (Figure 3). To ssess the 3D sptil position of the glenoid fosse, the nterior wll of sell turcic ws designted s the intersection of ll three Crtesin plnes nd given 0.0.0. coordinte. Coordintes for the most superior point of the glenoid fosse were extrcted to ssess X (right left), Y (nterior posterior), Z (superior inferior), nd 3D Eucliden displcement reltive to sell turcic. Figure 2. Lndmrks nd mesures. (1) P1 to front mxillo nsl; (2) P2 to front mxillo nsl; (3) C to front mxillo nsl; (4) C to P1; (5) C to P2; (6) C to mid-sgittl line (MSL). Sttisticl Anlysis The relibility of mesurements (ie, intrexminer repetbility nd interexminer reproducibility) ws tested with the intrclss correltion coefficient. For ll liner nd ngulr mesurements, intrexminer intrclss correltion coefficient ws clculted with the remesurement of 42 rndomly chosen individuls Figure 3. Glenoid foss ngultion reltive to the mid-sgittl line. The tngent lines to the medil nd lterl wlls of the glenoid foss form the ngle of the glenoid foss (A1) reltive to the mid-sgittl line (MSL).
850 DE MATTOS, PALOMO, DE OLIVEIRA RUELLAS, CHEIB, ELILIWI, SOUKI Tble 1. Gender Comprison of the Temporomndibulr Joint Position of Clss II Subdivision Ptients Mle Right Side Femle Left Side Mesurement Men SD Men SD P Vlue Men SD Men SD P Vlue P1-SP 53.3 5.2 50.2 3.2.035* 53.7 5.2 50.9 3.6.006* P2-SP 69.3 5.4 65 8.1.046* 70.5 5.3 66.9 3.4.002* C-SP 61.2 5.1 58.4 3.5.032* 62.6 5.2 59.8 3.8.036* C-P1 8.3 1.3 8.2 1.2.673 8.1 1.4 8.1 1.4.960 C-P2 7.9 1.1 8.3 1.2.319 7.9 1 7.4 1.4.170 C-MSL 48.5 2.6 45.9 3.1.006* 48.4 3.3 46.3 1.9.017* A1 19.5 4.2 19.3 4.1.851 20 3.7 19 2.9.365 SD indictes stndrd devition. sterisks indictes sttisticl difference between groups Mle Femle fter 2-week intervl. Interexminer greement ws confirmed with the remesurement of 20 individuls. Descriptive sttistics, including mens, stndrd devitions, nd medins, were clculted for ll vribles. The chi-squre test ws used to ssess gender differences in both groups. For quntittive nlysis, ssumptions of normlity nd homoscedsticity were confirmed using the Kolmogorov Smirnov nd Levene sttisticl tests, respectively. Pired t-tests were used to compre Clss I nd Clss II sides of C2SD nd the right nd left sides of C2 ptients, wheres n independent t-test ws used to compre the position of the glenoid fosse between groups (C2SD nd C2). Anlysis ws performed using the Sttisticl Pckge for the Socil Sciences version 16.0 (SPSS Inc, Chicgo, Ill), for which the level of significnce ws set t 5%. RESULTS High greement (intrclss correltion coefficient 0.8) ws found for ll mesures. The distribution of mles nd femles in the smple ws similr in ll groups (P ¼.822, chi-squre). An overll greter bsolute distnce between the glenoid fosse nd the nterior crnil bse or sell turcic ws found in the mles, lthough the condyles were centrlly positioned in the glenoid fosse in both genders. In both the C2SD (Tble 1) nd C2 groups (Tble 2), sttisticlly significnt gender differences were found regrding the distnce from the glenoid fosse to the nterior crnil bse s well s from the condyles to the nterior crnil bse. Glenoid fosse in the mles were more distlly nd lterlly positioned reltive to the fiduciry nterior crnil bse reference becuse the crnil bse dimensions were greter in the mles thn in the femles. However, condyles were symmetriclly positioned within the right nd left glenoid fosse in both the mles nd femles (Tbles 1 nd 2). Symmetry in the position of the glenoid fosse ws found in ptients with Clss II mlocclusion, but not in those with Clss II subdivision mlocclusion, both reltive to the FMN nd to the sell turcic. Those with Clss II mlocclusion showed symmetric sptil positioning of the right nd left sides nd the glenoid fosse nd mndibulr condyles. No sttisticlly significnt difference (P..05) ws found between the right nd left sides of ptients in the C2 group (Tble 3). However, ptients in the C2SD group (Figure 4 nd Tble 4) exhibited glenoid fosse on the Clss II side tht were more distlly nd lterlly positioned thn those on the Clss I side (P vlue rnging from.003 to.046), suggesting n symmetric condyle foss crnil bse reltionship. No positionl differences of the Clss I side in ptients in the C2SD group Tble 2. Gender Comprison of the Temporomndibulr Joint Position of Clss II Ptients Mle Right Side Femle Left Side Mesurement Men SD Men SD P Vlue Men SD Men SD P Vlue P1-SP 51 4.8 47.3 4.1.014* 51.9 5.1 47.6 4.8.010* P2-SP 65.9 5.6 61.9 4.7.016* 67.2 5.4 62.9 5.2.015* C-SP 58.9 5.3 54.3 4.2.006* 59.9 4.9 54.3 5.9.002* C-P1 7.9 1.1 7.3 1.3.093 7.6 1.1 7 1.1.086 C-P2 7.9 1.3 7.3 1.6.217 7.7 1.5 7.2 1.3.289 C-MSL 49.1 2.4 47.1 3.9.031* 48.3 2.5 46.8 2.1.047* A1 17.7 3.8 16.9 3.9.491 18.9 3.1 17.7 4.3.347 SD indictes stndrd devition. sterisks indictes sttisticl difference between groups Mle Femle
FOSSA AND CONDYLE POSITION IN CLASS II SUBDIVISION 851 Tble 3. Comprison of the Right nd Left Sides of the Temporomndibulr Joint Position of Clss II Ptients, According to Gender Right Mle Left Femle Mesurement Men SD Men SD P Vlue Men SD Men SD P Vlue P1-SP 51 4.8 51.9 5.1.413 47.3 4.1 47.6 4.8.761 P2-SP 65.9 5.6 67.2 5.4.287 61.9 4.7 62.9 5.2.363 C-SP 58.9 5.3 59.9 4.9.377 54.3 4.2 54.3 5.9.999 C-P1 7.9 1.1 7.6 1.1.220 7.3 1.3 7 1.1.262 C-P2 7.9 1.3 7.7 1.5.520 7.3 1.6 7.2 1.3.756 C-MSL 49.1 2.4 48.3 2.5.200 47.1 3.9 46.8 2.1.665 A1 17.7 3.8 18.9 3.1.121 16.9 3.9 17.7 4.3.380 SD indictes stndrd devition. sterisks indictes sttisticl difference between groups Right Left or on either side in ptients in the C2 group were found (Tble 5). Nevertheless, the glenoid fosse were significntly more distlly positioned (P vlue rnging from.005 to.024) on the Clss II side of ptients in the C2SD group reltive to FMN (Tble 6) when compred with both sides of ptients in the C2 group. Reltive to sell turcic, however, there were no sttisticlly significnt differences (P vlue rnging from.115 to.488 mong ll 3D components), despite the 0.8-mm more forwrd positioned glenoid foss of the Clss II side of C2SD ptients in comprison with C2 individuls (Tble 7). DISCUSSION Becuse the position of the mndible reltive to the fce is highly dependent on the position of glenoid fosse reltive to the crnil bse, investigtions into the topic re necessry to understnd the complex components of Clss II subdivision skeletl ptterns. Studies of mndibulr morphology tht do not consider the reltionships mong the condyle, foss, nd crnium cnnot explin the complex reltionship tht culmintes in dentofcil symmetry. Figure 4. Axil view of the cone bem computed tomogrphy from Clss II subdivision ptient showing the symmetric position of the glenoid fosse reltive to the nterior crnil foss nd the symmetric position of the condyles within the glenoid fosse. Although pioneering 2D studies found tht the primry etiologicl fctor of Clss II subdivision mlocclusion ws dentl symmetry without skeletl bnormlities, 4,5,13,16,17 recent 3D investigtions hve concluded tht symmetric mndibulr length nd glenoid fosse positioning reltive to the crnil bse might lso contribute to unblnced Clss II mlocclusion. 9,10,11 The current study corroborted the recent findings of Li et l., 11 who reported right- nd left-side differences in sptil positioning of glenoid fosse of ptients with Clss II subdivision mlocclusion. Although they ssessed the position of glenoid fosse in Clss II subdivision in comprison with Clss I ptients, the present study is the first to hve compred Clss II subdivision with skeletl Clss II ptients. The primry etiology of occlusl symmetries is complex, nd the literture offers no consensus bout their exct cuse. 10 12 Such uncertinty is of concern to clinicins becuse there is difficulty in dignosing nd treting ptients with Clss II subdivision mlocclusion, Tble 4. Temporomndibulr Joint Position of Clss II Subdivision Mle nd Femle Ptients Compring the Clss I Side nd Clss II Side Clss II Side Clss I Side P Mesurement Men SD Men SD Difference Vlue Mle P1-SP 54.3 5.5 51.3 3.4 3.0.013* P2-SP 69.7 5.8 66.1 5.4 3.6.003* C-SP 61.7 5.5 60.1 3.8 1.6.046* C-P1 8.4 1.0 7.6 1.4 0.5.284 C-P2 7.6 1.0 8.4 1.5 0.8.601 C-MSL 49.2 2.2 47.8 2.7 2.5.026* Femle P1-SP 49.9 3.7 47.4 2.4 2.5.024* P2-SP 66.7 4.2 63.7 3.2 3.0.007* C-SP 59.4 1.9 58 2 1.4.026* C-P1 8.3 1 8.1 1.2 0.2.581 C-P2 8.6 1.2 8.1 1.3 0.5.402 C-MSL 45.8 3.1 45.9 3.7 0.1.756 SD indictes stndrd devition. sterisks indictes sttisticl difference between groups
852 DE MATTOS, PALOMO, DE OLIVEIRA RUELLAS, CHEIB, ELILIWI, SOUKI Tble 5. Comprison Between Clss II Group nd Clss I Side of Clss II Subdivision Group Mesurement C2 Clss I Side of C2SB Men SD Men SD Difference P Vlue P1-SP 49.6 4.8 51.8 3.4 2.2 0.144 P2-SP 64.3 5.6 66.2 10 1.9 0.392 C-SP 57 5.3 60 3.3 2.9 0.078 C-P1 7.5 1.2 7.9 1.1 0.4 0.379 C-P2 7.6 1.4 8.2 1.3 0.6 0.215 C-MSL 48.1 3.1 46.7 3.3 1.4 0.187 A1 17.4 3.8 19.8 2.5 2.8 0.059 C2 indictes Clss II group; C2SB, Clss II subdivision group; SD, stndrd devition. sterisks indictes sttisticl difference between groups Tble 6. Comprison Between Clss II Group nd Clss II Side of Clss II Subdivision Group Mesurement Angle Clss II, C2 Clss II Side, C2SB Men SD Men SD Difference P Vlue P1-SP 49.6 4.8 52.7 5.3 3.1.023* P2-SP 64.3 5.6 68.6 5.4 4.3.005* C-SP 57.1 5.3 60.4 5.4 3.2.024* C-P1 7.5 1.2 8.4 1.3 0.86.014* C-P2 7.6 1.4 8 1.2 0.4.348 C-MSL 48.1 3.1 48 3.1 0.1.916 A1 17.4 3.8 19.9 4.2 2.5.021* C2 indictes Clss II group; C2SB, Clss II subdivision group; SD, stndrd devition. sterisks indictes sttisticl difference between groups prticulrly regrding the possibility of trnsforming the Clss II side into Clss I reltionship. If the concept of n symmetric morphogenetic pttern offers ftlistic explntion of the difficulty of performing tretments for Clss II subdivision, 3,9 then the fct tht the origin of the problem in ptients with n symmetric occlusl reltionship is the uneven sgittl positions of the glenoid fosse offers orthodontists mostly dentolveolr therpeutic lterntives s compenstion. The literture on the tretment of Clss II subdivision mlocclusion using dentofcil orthopedics is scrce. Bock et l. 18 presented the only functionl pplince study on the tretment of symmetric Clss II ptients nd found, by mens of study models, tht symmetric Herbst tretment demonstrted success tht ws similr to symmetric Clss II Herbst tretment with respect to the occlusl correction. Ars nd Psoglu 19 reported tht ptients with Clss II subdivision mlocclusion treted with Forsus ftigue resistnt device were corrected minly by dentolveolr chnges, without significnt skeletl modifictions. In tht light, the current findings point out significnt crnil bse skeletl contribution to the development of Clss II subdivision tht, lthough consistent with other reports, 11,20 is beyond the therpeutic rnge of correction for orthodontists. The present results lso show tht the Clss II side in ptients, especilly mles with Clss II subdivision, is more lterlly positioned reltive to the MSL. It cn therefore be inferred tht Clss II subdivision is ssocited with n xil rottion of the mndibulr fosse, with center of rottion on the Clss I side nd distliztion of the foss on the Clss II side. However, the current findings do not fully gree with those of other 2D studies. 4,5,13 Such differences might be result of the limittions of 2D. 7,8,12 The difficulty of visulizing the TMJ in 2D exms derives from its complex ntomy nd the overlp of djcent structures. This my hve contributed to differences between the current nd previously reported results. 2,9,17 In contrst, CBCT imges do not present such bises nd llow the quntittive nd qulittive ssessment of bone in ctul dimensions. 9,20,21 As such, 3D imging hs opened new horizon in scientific fields, nd new evidence to confirm previous reports or t lest show tht different wys of thinking re needed. The first cse-control investigtion tht used CBCT technology to ssess the etiology of Clss II subdivision mlocclusion showed different results from wht 2D studies hd previously provided, 9 nd it concluded tht the cuse of Clss II subdivision mlocclusion ws chiefly result of shorter mndible on the Clss II side. However, in tht study, comprehensive nlysis of the glenoid fosse nd condylr positioning reltive to stble crnil bse structure ws not performed. The previous literture lcks gender comprisons of the positioning of the glenoid fosse in ptients with Clss II subdivision mlocclusion. In the present study, ssocited with greter dimensions of the crnil bse, mles presented with glenoid fosse in more posterior position reltive to the nterior crnil bse nd more lterlly positioned reltive to the midsgittl line. No ssocition between gender nd the degree of symmetry of the position of the glenoid fosse ws found. Condylr positioning within the glenoid foss ws similr, independent of the Clss II group or gender, in ccordnce with previous studies performed with pnormic rdiogrphs 13 nd CBCT. 22,23 The skeletl positionl symmetry of the mndibulr fosse nd mndibulr condyles in Clss II subdivision mlocclusion is reltively new concern in orthodontics, nd controversies persist. Additionl 3D studies, including comprehensive ssessments of ll dentoskeletl components, re therefore necessry. This study concluded tht, in ptients with Clss II subdivision mlocclusion, it is likely tht the right- nd left-side mndibulr fosse re symmetriclly positioned nd the condyles symmetriclly positioned within the glenoid fosse. Moreover, mle ptients
FOSSA AND CONDYLE POSITION IN CLASS II SUBDIVISION 853 Tble 7. Comprison Between the Three-Dimensionl Position nd the X, Y nd Z Distnces of the Glenoid Fosse Reltive to Sell Turcic of Clss II Subdivision Ptients (Both the Clss II Side nd the Clss I Side), nd the Men Vlue of Both Sides of Clss II Ptients Comprisons Coordintes b Groups Men SD Clss II side (CII S) vs Clss I side (CI S) of C2SD ptients Clss II sides of C2 ptients (C2) vs Clss II side of C2SD ptients (ClI S) Clss II side of C2 ptients (C2) vs Clss I side of C2SD ptients (CI S) Men Difference 95% CI P Vlue X CII S 46.7 2.1 1.1 0.8 to 1.5.000* CI S 45.6 2.3 Y CII S 18.2 2.3 0.7 0.7 to 1.9.022* CI S 17.5 2.5 Z CII S 14.3 2.6 0.2 0.6 to 1.1.523 CI S 14.0 3.4 3D CII S 52.3 2.2 1.3 1.1 to 1.4.000* CI S 50.9 2.2 X C2 46.3 2.1 0.4 1.4 to 0.5.350 ClI S 46.7 2.1 Y C2 17.4 2.2 0.8 1.8 to 0.2.115 ClI S 18.2 2.3 Z C2 14.7 2.9 0.4 1.6 to 0.8.488 ClI S 14.3 2.6 3D C2 51.7 2.4 0.5 1.6 to 0.4.283 ClI S 52.2 2.2 X C2 46.3 2.1 0.7 0.2 to 1.7.143 CI S 45.6 2.3 Y C2 17.5 2.2 0.0 0.9 to 1.1.865 CI S 17.5 2.5 Z C2 14.7 2.9 0.7 0.7 to 2.1.316 CI S 14.0 3.4 3D C2 51.6 2.4 0.7 0.2 to 1.7.152 CI S 50.9 2.2 Itlic font indictes n ssocition with sttisticlly significnt difference. CII S indictes Clss II side of subdivision ptients; CI S, Clss I side of subdivision ptients; C2, both sides of Clss II ptients; SD, stndrd devition; CI, confidence intervl. b X nd Y were mesured in the xil view, nd Z ws mesured in the coronl view. 3D mens the Eucliden distnce between the glenoid fosse nd sell turcic. X, mesil lterl; Y, nterior posterior; Z, superior inferior projections. displyed greter distnces between the glenoid fosse nd ntomic references in the nterior crnil bse despite there being no differences in condylr position within the glenoid fosse. CONCLUSIONS The null hypotheses were rejected. Asymmetric positioning of the glenoid fosse ws found in Clss II subdivision ptients, wheres symmetry ws found in ptients with Clss II mlocclusion. In the former group, the Clss II side ws more posteriorly nd lterlly positioned thn the Clss I side. Mndibulr condyles were centrlly positioned within the glenoid fosse in ptients with Clss II mlocclusion or Clss II subdivision mlocclusion, without ny differences by gender. Mle ptients showed more posteriorly nd lterlly positioned glenoid fosse thn did the femle ptients. ACKNOWLEDGMENT We thnk The Angle Orthodontist reviewer for the suggestion of dding the 3D mesurements reltive to Sell. REFERENCES 1. Droel R, Iscson RJ. Some reltionships between the glenoid foss position nd vrious skeletl discrepncies. Am J Orthod. 1972;61:64 78. 2. Giuntini V, Toffol L De, Frnchi L, Bccetti T. Glenoid foss position in clss ii mlocclusion ssocited with mndibulr retrusion. Angle Orthod. 2008;78:808 812. 3. Alvi DG, BeGole EA, Schneider BJ. Fcil nd dentl rch symmetries in Clss II subdivision mlocclusion. Am J Orthod Dentofc Orthop.1988;93:38 46. 4. Rose JM, Sdowsky C, BeGole EA, Moles R. Mndibulr skeletl nd dentl symmetry in clss II subdivision mlocclusions. Am J Orthod Dentofcil Orthop. 1994;105:489 495. 5. Jnson GRP, Metxs A, Woodside DG, De Freits MR, Pinzn A. Three-dimensionl evlution of skeletl nd dentl symmetries in clss II subdivision mlocclusions. Am J Orthod Dentofc Orthop. 2001;119:406 418. 6. Azevedo AR, Jnson G, Henriques JF, Freits MR. Evlution of symmetries between subjects with clss II subdivision nd pprent fcil symmetry nd those with norml occlusion. Am J Orthod Dentofc Orthop. 2006;129:376 383. 7. Adenwll ST, Kronmn JH, Attrzdeh F. Porion nd condyle s cephlometric lndmrks n error study. Am J Orthod Dentofc Orthop. 1988;94:411 415. 8. Snders DA, Rigli PH, Nece WP, Uribe F, Nnd R. Skeletl nd dentl symmetries in Clss II subdivision
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