Dentofacial Effects of Asymmetric Headgear and Cervical Headgear with Removable Plate on Unilateral Molar Distalization

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1 Originl Article Dentofcil Effects of Asymmetric Hedger nd Cervicl Hedger with Removble Plte on Unilterl Molr Distliztion Hndn Altug ; A. Osmn Bengi b ; Erol Akın; c Seniz Krcy d Abstrct: Cervicl hedger (CHG) is used widely in the tretment of Clss II nomlies. Asymmetric hedger (AHG) is n lterntive tretment for the correction of unilterl Clss II dentl reltionships. The purpose of this investigtion ws to compre the effects of AHG with those of CHG combined with removble plte in unilterl first molr distliztion. The study consisted of 20 ptients with unilterl Clss II molr reltionship (12 girls nd eight boys). One group of 10 ptients ws treted with n AHG, nd second group of 10 ptients ws treted with CHG nd removble plte. Lterl cephlogrms nd bsilr rdiogrphs were tken before nd fter molr distliztion. It ws found tht distliztion nd distl tipping of molr on the pssive side ws less in the CHG nd removble plte (CHG-RP) group. Distliztion nd distl tipping of the second premolr on the distliztion side ws lso reduced in this group. Incisors were retruded in both groups but were retruded more in the CHG-RP group. (Angle Orthod 2005;75: ) Key Words: Clss II mlocclusion; Asymmetric hedger; Cetlin therpy; Unilterl molr distliztion INTRODUCTION Hedgers were first used in the erly 1800s, nd modifictions hve been mde throughout time. Cervicl hedger (CHG) therpy hs been studied extensively for the lst 50 yers, but tretment results hve vried gretly becuse of modifictions of the pplince. Extrorl trction hs been used successfully to correct skeletl or dentl Clss II mlocclusion by restrining the forwrd growth of the mxill or by Specilist, Deprtment of Orthodontics, Dentl Science Center, Gulhne Militry Medicl Acdemy, Ankr, Turkey. b Associte Professor, Deprtment of Orthodontics, Dentl Science Center, Gulhne Militry Medicl Acdemy, Ankr, Turkey. c Assistnt Professor, Deprtment of Orthodontics, Dentl Sciences Center, Gulhne Militry Medicl Acdemy, Ankr, Turkey. d Assistnt Professor, Deprtment of Orthodontics, Dentl Science Center, Gulhne Militry Medicl Acdemy, Ankr, Turkey. Corresponding uthor: Erol Akın, DDS, PhD, Deprtment of Orthodontics, Dentl Science Center, Gulhne Militry Medicl Acdemy, Gn. Tevfik Sglm Cd., Ankr, Etlik 06018, Turkey (e-mil: erol1kin@hotmil.com) Accepted: November Submitted: August by The EH Angle Eduction nd Reserch Foundtion, Inc. distlizing the mxillry molrs. The effects of CHG on the crniofcil complex hve been evluted by numerous experimentl nd clinicl studies. 1 8 However, extrorl cervicl trction requires considerble ptient complince to obtin successful results. 5,9 11 In recent yers, methods hve been sought for correcting Clss II mlocclusions without the need for strict ptient complince. Different tretment modlities hve been suggested to distlize mxillry molrs including pltl brs, 12 repelling mgnets, Nitinol coil springs, K-loops, 19 superelstic wires, 20 Wilson rches, 21 Jones jig pplinces, 22,23 pendulum pplinces, 24 distl jet pplinces, 25 three-dimensionl bimetric mxillry distlizing rches, 26 nd introrl bodily molr distlizer. 27,28 In the erly 1980s, Cetlin nd Ten Hoeve 29 introduced nonextrction tretment method for Clss II division 1 mlocclusion, which corrected the molr reltionship with the use of distlizing plte combined with extrorl trction. Extrorl trction should be worn 10 to 12 hours dy nd produce force of 150 to 200 g/side, or more, for n orthopedic effect on the mxill. Orthodontic tretment often requires n extrorl fcebow tht will predictbly deliver greter distl force to one side of the dentl rch. Fcebows provid- 584

2 UNILATERAL MOLAR DISTALIZATION 585 FIGURE 1. Points nd plnes used in the cephlometric nlysis: (1) Ud6, inserting point of the mrker t distliztion side; (2) Up6, inserting point t pssive side; (3) U5, distl point of the mxillry second bicuspid t distliztion side; (4) Ud6o, lower point of the mxillry first molr t distliztion side; (5) Up6o, lower point t pssive side; (6) U5o, lower point of the mxillry second bicuspid t the distliztion side; (7) U1i, incisl point of the mxillry incisor; (8) Ud6, long xis of the mrker t distliztion side; (9) Up6, long xis of the mrker t pssive side. ing n symmetric distl force to their inner-bow terminls re termed unilterl fcebows. Studies describing the dentoskeletl chnges ssocited with the Cetlin method hve been rre. The im of this study ws to evlute nd to compre the dentoskeletl chnges produced by CHG used with removble plte (CHG-RP) with those effects produced by n symmetric hedger (AHG). FIGURE 2. Mesurements used in the cephlometric nlysis: (10) U5, long xis of the mxillry second bicuspid t the distliztion side; (11) Ud6/FH; (12) Up6/FH; (13) U5/FH; (14) Ud6-PtV; (15) Up6-PtV; (16) U5-PtV; (17) U1i-PtV; (18) Ud6o-FH; (19) Up6o-FH; (20) U5o-FH; (21) U1i-FH. MATERIALS AND METHODS This prospective study consisted of 20 ptients (12 girls nd eight boys) divided rndomly into two groups. Group I (AHG group) comprised 10 children (seven girls nd three boys) with men ge of 14.1 yers, nd group II (CHG-RP group) comprised 10 children (five girls nd five boys) with men ge of 14.6 yers. Cses were selected with inclusion criteri s: (1) skeletl Clss I, unilterl dentl Clss II molr reltionship, (2) norml growth pttern nd direction, (3) lower midline coincident with the midsgittl plne (MSR), (4) miniml or no dentolveolr discrepncies in the lower rch, (5) norml overbite, (6) erupted upper second molrs, nd (7) bsence of ny shpe or size nomlies or congenitl missing tooth or teeth. The study ws crried out fter the institutionl pprovl for the use of humns ws obtined from ethics committee of Gulhne Militry Medicl Acdemy. The mxillry first molrs were unilterlly distlized using 250 g of force in both groups. Records of ll the ptients were obtined before tretment (T1) nd fter molr distliztion (T2). Distliztion ws considered dequte when super Clss I molr reltionship ws obtined. The pplinces were removed t the end of distliztion, nd pssive trnspltl rch ws inserted for retention. Rdiogrphic evlution Lterl nd bsilr rdiogrphs were obtined before nd fter the distliztion period. Molr positions were identified on the rdiogrphs by the use of individul verticlly oriented guiding mrkers ( mm Blue Elgiloy) plced in the rectngulr double buccl tubes of molr bnds while obtining the rdiogrphs. Occlusl rdiogrphs were tken for evidence of suturl opening. One investigtor (Dr Altug) trced the rdiogrphs, nd the lndmrks were verified by the other three investigtors. Suspicious structures nd lndmrks were retrced to the mutul stisfction of the investigtors. A single verge trcing ws mde in instnces of bilterl structures. Twenty-three lndmrks nd 32 prmeters were used in the study. The prmeters were mesured by one investigtor (Dr Altug) once more t nother time to evlute mesurement errors. Mesurements used in the study re shown in Figures 1 4 nd Tbles 1 nd 2. The fre-

3 586 ALTUG, BENGI, AKIN, KARACAY FIGURE 3. Points used in the bsilr nlysis; (1) GI; (2) PPCB, tip of the posterior border of crnium; 3. SOR nd SOL, intersection between the l minor of the sphenoid bone nd lterl wll of the orbit t the right nd left sides; 4. MADD nd MAPD: distl point of lveolr bone t distliztion nd pssive side; 6. DPD nd DPD, distopltl corner t distliztion nd pssive side; 7. DBD nd DBP, distobuccl corner t distliztion nd pssive side; 8. MPD nd DPP, mesiopltl corner t distliztion nd pssive side; 9. MPC nd MPC, the intersection point between the plnes connecting MB to DP nd MP to DB t distliztion nd pssive side; 10. PVD nd PVP, vestibule point of the mxillry second bicuspid t tdistliztion nd pssive side; 11. PPD nd PPP, pltl point of the mxillry second bicuspid t distliztion nd pssive side; 12. PDC nd PPC, midpoint of the plne connecting PVB to PPD; (13) I, contct point of mxillry of mxillry incisors. quently used points nd mesurements re not shown in the figures. Sttisticl method Thirty-two lterl nd bsilr rdiogrphs were chosen rndomly for exmintion of the mesurement error. The relibility of single mesurement ws clculted by using Dhlberg s formul of method error. The method error did not exceed Sttisticl nlyses were performed with sttisticl pckge (SPSS Inc, Chicgo, Ill), nd the results re shown s men stndrd devition. After the prmetric ssumptions were tested nd if the vribles were suitble for prmetric tests, the differences between the T1 nd T2 mesurements were evluted with the pired-smples t-test. The differences FIGURE 4. Mesurements used in the bsilr nlysis: (14) midsgittl plne (MSR), plne connecting Gl to PPCB; (15) trnsversl plne (TP), plne connecting SOR to SOL; 16. MADD-MSR; 17. MADD-MAPD; 18. MADD-TP; 19. MBD-DPD/MSR nd MBP-DPP/ MSR; 20. PVD-PVP/MSR nd PVP-PPP/MSR; 21. MPC-MSR nd MPC-MSR; 22. MDC-MPC; 23. PDC-MSR; 24. MDC-TP; 25. PDC- TP; 26. I-TP. between the two groups were evluted using Student s t-test. P vlues.05 were considered sttisticlly significnt. RESULTS The T1 to T2 chnges of the groups in the cephlometric nd bsilr rdiogrphs re shown in Tbles 3 through 6. The y-xis (P.01 for AHG nd P.05 for CHG-RP), pltl plne (P.05 for AHG nd P.01 for CHG-RP), mndibulr plne (P.01 for both groups), nd occlusl plne (P.01 for AHG nd P.05 for CHG-RP) ll reveled posterior rottion. Anterior nd lower fce heights (P.01 for both groups) nd posterior fce height (P 05 for AHG nd P.01 for CHG-RP) were incresed. Upper molrs nd centrl incisors were extruded in both groups, nd it ws denoted by increses in the cephlometric vribles Ud6o-FH, Up6o-FH, nd U1i- FH (P.01 for AHG nd P.05 for CHG-RP). Extrusion of the second premolrs ws observed only in AHG group (U5o-FH ws incresed by P.01). Distopltl rottion of the first molrs nd second premolrs ws determined by increses in bsilr vr-

4 UNILATERAL MOLAR DISTALIZATION 587 TABLE 1. Ud6 Up6 U5 Ud6o Up6o U5o U1i Ud6 Up6 U5 Ud6/FH Up6/FH U5/FH Ud6-PtV Up6-PtV U5-PtV U1i-PtV Ud6o-FH Up6o-FH U5o-FH U1i-FH Explntion of the Abbrevitions Used in the Cephlometric Anlysis, Figures, nd Tbles Inserting point of the mrker to the tube on the mxillry first molr t distliztion side Inserting point of the mrker to the tube on the mxillry first molr t pssive side Distl point of the mxillry second bicuspid t distliztion side Lower point of the mxillry first molr t distliztion side Lower point t pssive side Lower point of the mxillry second bicuspid t the distliztion side Incisl point of the mxillry incisor Long xis of the mrker t distliztion side Long xis of the mrker t pssive side Long xis of the mxillry second bicuspid t the distliztion side The lower, inner ngle between Ud6 nd Frnkfort Horizontl plne The lower, inner ngle between Up6 nd Frnkfort Horizontl plne The lower, inner ngle between U5 nd Frnkfort Horizontl plne The perpendiculr distnce between Ud6 nd Pterygoid Verticle plne The perpendiculr distnce between Up6 nd Pterygoid Verticle plne The perpendiculr distnce between U5 nd Pterygoid Verticle plne The perpendiculr distnce between U1 nd Pterygoid Verticle plne The perpendiculr distnce between Ud6 nd Frnkfort Horizontl plne The perpendiculr distnce between Up6 nd Frnkfort Horizontl plne The perpendiculr distnce between U5 nd Frnkfort Horizontl plne The perpendiculr distnce between U1 nd Frnkfort Horizontl plne ibles MBD-DPD/MSR, MBP-DPP/MSR, PVP-PPP/ MSR (P.01 for both groups), nd PVD-PPD/MSR (P.01 for AHG nd P.05 for CHG-RP), wheres the expnsion of these teeth ws shown by increses in MDC-MSR, MDC-MPC, PDC-MSR (P.01 for both groups), nd MPC-MSR, PPC-MSR (P.01 for AHG nd P.05 for CHG-RP). Distliztion of molrs nd premolrs ws denoted by increses in bsilr vribles MDC Trnsversl Plne (TP), MPC-TP, PDC-TP (P.01 for both groups) nd PPC-TP (P.01 for AHG nd P.05 for CHG-RP). Cephlometric findings lso reveled distliztion nd distl tipping of these teeth by decreses in the vribles Ud6/FH, Up6/FH, U5/FH, Ud6-Ptv, Up6-Ptv, nd U5-Ptv (P.01 for both groups). Upper incisors were retruded in both groups (U1i- Ptv ws decresed by P.01 for AHG nd P.05 for CHG-RP), nd they were lso distlly tipped in CHG-RP group (U1/SN ws decresed by P.05 nd I-TP ws decresed by P.01). Significnt increses in the bsilr vribles MADD- MSR, MAPD-MSR, MADD-MAPD, MADD-TP, nd MAPD-Trns (P.01) showed the displcement of the lveolr bone in both groups. When the mens of the groups were compred, significnt chnges were found in vribles Up6/FH, Up6-Ptv, nd U5-Ptv (P.05) nd U5/FH (P.01) showing more distliztion nd distl tipping of molr t the pssive side nd of second premolr t the distliztion side in AHG group (Tble 7). DISCUSSION Alterntive introrl molr distliztion modlities hve been sought to crete noncomplince therpies. Becuse the most unvoidble effect of introrl molr distliztion is the undesirble ltertions in the lveolr bone nd the nchor teeth, these pplinces were suggested for use before eruption of the second molrs. 15,16,20,22,24 Severl AHG forms hve been used for unilterl molr distliztion An undesirble effect of the AHG is the derngement of the upper molrs in the sgittl nd trnsverse plnes becuse of lterl forces. 31 In this study, removble plte with screw nd CHG combintion ws used to eliminte these lterl forces. Studies of distliztion were conducted usully on bilterl mxillry molrs. Severl uthors hve investigted unilterl molr distliztion with introrl pplinces. In the literture, despite the investigtions explining the biomechnics of extrorl unilterl molr distliztion, the number of clinicl trils is few. The direction of verticl force could be controlled with the ngultion of outer rms of the fcebow, but in this sitution, decresed mount of molr distliztion should be expected. Our first trget ws to obtin rpid molr distliztion, so ngulr ltertions were not performed to the outer rms nd 250 g of force ws pplied in our study. In bilterl CHG pplictions, force lines intersect t the posterior of the neck on the MSR t n illusive point. The force vector occurs s the bisector of the ngle formed by the force lines psses through the MSR nd the midpoint of the distnce between the upper molrs. When the geometric configurtions of the unilterl CHG were evluted, the ngle formed by the force lines is lso t the posterior of the neck but is positioned to the side tht is to be stble. In this condition, the force component runs in direction tht

5 588 ALTUG, BENGI, AKIN, KARACAY TABLE 2. Explntion of the Abbrevitions Used in the Bsilr Anlysis, Figures, nd Tbles GI Gibell PPCB Tip of the posterior border of crnium SOR Intersection between the l minor of the sphenoid bone nd lterl wll of the orbit t the right side SOL Intersection between the l minor of the sphenoid bone nd lterl wll of the orbit t the left side MADD Distl point of lveolr bone t distliztion side MAPD Distl point of lveolr bone t pssive side MBD Point constituting the mesiobuccl corner of the mxillry first molr t distliztion side MBP Point constituting the mesiobuccl corner of the mxillry first molr t pssive side DPD Point constituting the distopltl corner of the mxillry first molr t distliztion side DPP Point constituting the distopltl corner of the mxillry first molr t pssive side DBD Point constituting the distobuccl corner of the mxillry first molr t distliztion side DBP Point constituting the distobuccl corner of the mxillry first molr t pssive side MPD Point constituting the mesiopltl corner of the mxillry first molr t pssive side DPP Point constituting the mesiopltl corner of the mxillry first molr t pssive side MDC The intersection point between the plnes connecting MB to DP nd MP to DB t distliztion side MPC The intersection point between the plnes connecting MB to DP nd MP to DB t pssive side PVD Vestibule point of the mxillry second bicuspid t distliztion side PVP Vestibule point of the mxillry second bicuspid t pssive side PPD Pltl point of the mxillry second bicuspid t distliztion side PPP Pltl point of the mxillry second bicuspid t pssive side PDC Midpoint of the plne connecting PVD to PPD t distliztion side PPC Midpoint of the plne connecting PVP to PPP t pssive side I Contct point of mxillry centrl incisors MSR Midsgittl plne: plne connecting GI to PPCB TP Trnsversl plne: plne connecting SOR to SOL MADD-MSR The perpendiculr distnce with the distl point of lveolr bone t distliztion side nd MSR MADD-MAPD The perpendiculr distnce with the distl point of lveolr bone t pssive side nd MSR MADD-TP The perpendiculr distnce with the distl point of lveolr bone t distliztion side nd TP MAPD-TP The perpendiculr distnce with the distl point of lveolr bone t pssive side nd TP MBD-DPD/MSR The ngle between the plne connecting MBD to DPD nd MSR t distliztion side MBP-DPP/MSR The ngle between the plne connecting MBP to DPP nd MSR t pssive side PVD-PVP/MSR The ngle between the plne connecting PVD to PVP nd MSR t distliztion side PVP-PPP/MSR The ngle between the plne connecting PVP to PPP nd MSR t pssive side MDC-MSR The perpendiculr distnce from MDC to MSR MPC-MSR The perpendiculr distnce from MPC to MSR MDC-MPC The distnce between MDC nd MPC PDC-MSR The perpendiculr distnce from PDC to MSR MDC-TP The perpendiculr distnce from MDC to TP PDC-TP The perpendiculr distnce from PDC to TP I-TP The perpendiculr distnce from I to TP crosses the MSR nd comes close to the upper molr desired to be distlized. Hershey et l 32 determined tht increse in the symmetry of the unilterl hedger leds to n increse in lterl force vector. In our study, short rm of the ACH ws t the level of upper bicuspids. The introrl molr distliztion techniques were often introduced in the literture, so the results of our study were compred with these investigtions. The y-xis, SN-PP, SN-MP, SN-Occ, N-Me, ANS- Me, nd S-Go vribles showed sttisticlly significnt increses in both groups. These ltertions reveled the chnges in the reltionship of mxill nd mndible ginst the crnil bse nd posterior rottion of the chin becuse of orthopedic nd dentolveolr effects of extrorl pplinces. Therefore, nterior fce height/posterior fce height rtio chnged nd the fcil height prmeters incresed. Sttisticlly significnt differences were found in the vribles MADD- MSR, MAPD-MSR, MADD-MAPD, MADD-TP, nd MAPD-TP. According to these findings, we concluded tht the lveolr bone moved distlly. When the dentolveolr effects of the pplinces were evluted, sttisticlly significnt differences were found in the mount of distliztion of the upper molrs. Mxillry molrs on the pssive side were lso distlized in both groups. This finding ws in ccordnce with Hershey et l 32 nd Bldini. 31 The betweengroup difference for this prmeter ws sttisticlly significnt. The distliztion ws more in the AHG group. This finding ws result of the plte tht fcilittes the distliztion in one side becuse of the screw nd tightens the contrlterl ginst the distliztion force of the hedger. Significnt ltertion in the Ud6/FH nd Up6/FH showed the tipping of the molrs. This finding ws sim-

6 UNILATERAL MOLAR DISTALIZATION 589 TABLE 3. Descriptive Sttistics of Skeletl/Dentl Mesurements of Lterl Cephlometric Rdiogrphs t T1, T2, nd T2 T1 for the Asymmetric Hedger Group T1 T2 T2 T1 P Significnce y-xis ** SN/PP * SN/MP ** SN/Occ ** N-Me ** ANS-Me ** S-Go * Ud6/FH ** Up6/FH ** U5/FH ** Ud6-Ptv ** Up6-Ptv ** U5-Ptv ** U1i-Ptv ** Ud6o-FH ** Up6o-FH ** U5o-FH ** U1i-FH ** T1 indictes before tretment; T2, fter tretment. TABLE 4. Descriptive Sttistics of Mesurements of Bsilr Rdiogrphs t T1, T2, nd T2 T1 for the Asymmetric Hedger Group T1 T2 T2 T1 P Significnce MADD-MSR ** MAPD-MSR ** MADD-MAPD ** MADD-TP ** MAPD-TP ** MBD-BPD ** MBP-DPP ** PVD-PPD ** PVP-PPP ** MDC ** MPC ** MDC ** PDC ** PPC ** MDC ** MPC ** PDC ** PPC ** I-TP * T1 indictes before tretment; T2, fter tretment. ilr to other investigtions evluting introrl molr distliztion. On the other hnd, Keles nd Syinsu 27 nd Keles et l 28 dvocted bodily tooth movement. The between-group differences reveled significnt ltertion for the vrible Up6/FH nd showed less distl tipping of the molr in the pssive side of CHG- RP group. The vribles describing the extrusion of the molrs incresed significntly in both groups, nd no sttisticlly significnce ws found between the groups. Extrusion of molrs is in ccordnce with Greenspn 6 nd Blck nd Poulsen 4 but conflicts with Ringenberg nd Butts. 8 In the evlution of the bsilr rdiogrphs, it ws found tht rottion of the molrs ws sttisticlly significnt in both groups. Rottion ws more in the AHG group, but the between-group differences were sttis-

7 590 ALTUG, BENGI, AKIN, KARACAY TABLE 5. Descriptive Sttistics of Skeletl/Dentl Mesurements of Lterl Cephlometric Rdiogrphs t T1, T2, nd T2 T1 for the Cervicl Hedger with Removble Plte Group T1 T2 T2 T1 P Significnce y-xis * SN/PP ** SN/MP ** SN/Occ * N-Me ** ANS-Me ** S-Go ** Ud6/FH ** Up6/FH ** U5/FH ** U1/SN * Ud6-Ptv ** Up6-Ptv ** U5-Ptv ** U1i-Ptv * Ud6o-FH * Up6o-FH * U5o-FH * U1i-FH * T1 indictes before tretment; T2, fter tretment. TABLE 6. Descriptive Sttistics of Mesurements of Bsilr Rdiogrphs t T1, T2, nd T2 T1 for the Cervicl Hedger with Removble Plte Group T1 T2 T2 T1 P Significnce MADD-MSR ** MAPD-MSR ** MADD-MAPD ** MADD-TP ** MAPD-TP ** MBD-DPD/MSR ** MBP-DPP/MSR ** PVD-PPD/MSR * PVP-PPP/MSR ** MDC-MSR ** MPC-MSR * MDC-MPC ** PDC-MSR ** PPC-MSR * MDC-TP ** MPC-TP ** PDC-TP ** PPC-TP * I-TP ** T1 indictes before tretment; T2, fter tretment. ticlly insignificnt. Although the crylic plte reduced the rottion of the molrs to degree, it could not prevent it completely. Contrry to our findings, Crno nd Test 25 dvocted no rottionl ltertions. Becuse of the molr rottions, intermolr width showed sttisticlly significnt increses in both groups. When the ltertions in the upper bicuspids were evluted, significnt distl movement, extrusion, nd distopltl rottion were observed in both groups. When the groups were compred, more distliztion nd distl tipping were found in AHG group. The bll loop nd the crylic were believed to be the

8 UNILATERAL MOLAR DISTALIZATION TABLE 7. Comprison of the Between-Group Differences t the End of Distliztion AHG, T2 T1 CHG-RP, T2 T1 P Significnce Up6/FH * U5/FH ** Up6-Ptv * U5-Ptv * U5o-FH * I-TP ** T1 indictes before tretment; T2, fter tretment; AHG, ssymmetric hedger; nd CHG-RP, cervicl hedger with removble plte. reson for the decresed distl movement in the CHG- RP. Jones nd White 22 nd Ucem et l 26 lso found distl tipping nd distliztion in the premolrs. Extrusion of the bicuspids ws lso found in the studies of Ghosh nd Nnd 33 nd Keles nd Syinsu. 27 However, mesil tipping of the upper bicuspids ws observed in most of the introrl molr distliztion techniques becuse they were used s nchor teeth. The vribles evluting the effect of the extrorl distliztion force on the incisors showed sttisticlly significnt ltertions. The incisor retrusion ws in ccordnce with the findings of other investigtors who used extrorl forces. The proclintion of the nterior teeth ws reported by severl uthors who used introrl molr distliztion methods The differences mong groups were lso sttisticlly significnt for these vribles. The pltl tipping of the nterior teeth ws more in the CHG-RP group. The reson my be the removble plte tht trnsferred the force to the nterior region through the lbil rch. Extrusion of the nterior teeth ws observed in both groups, which ws in ccordnce with the findings of other investigtions. 6,21 Soft tissue chnges were not significnt in both groups. CONCLUSIONS The unilterl distliztion of the mxillry molrs ws chieved effectively in both groups. In the AHG group, the mxillry first molrs on the pssive nd the second premolrs on the distliztion side were distlized more thn those in the CHG-RP group. Incisor retrusion ws more significnt with CHG-RP combintion. Pltl, occlusl, nd mndibulr plne ngles nd nterior nd posterior fce height were incresed in both groups. REFERENCES Angle EH. Regultion pplinces. Int Dent J. 1889;10: Kloehn SJ. Guiding lveolr growth nd eruption of teeth to reduce tretment time nd produce more blnced denture on fce. Angle Orthod. 1947;17: Weislnder L. The effect of orthodontic tretment on the concurrent development of the crniofcil complex. Am J Orthod. 1963;49: Blck IB, Poulsen A. Occipitl nchorge for distl movement of the mxillry first molrs. Act Odontol Scnd. 1966;24: Poulton DR. The influence of extrorl trction. Am J Orthod. 1967;53: Greenspn RA. Reference chrts for controlled extrorl force ppliction to mxillry molrs. Am J Orthod. 1970; 58: Merrifield LL, Cross JJ. Directionl forces. Am J Orthod. 1970;57: Ringenberg QM, Butts WC. A controlled cephlometric evlution of single-rch cervicl trction therpy. Am J Orthod. 1970;57: Clemmer EJ, Hyes EW. Ptient coopertion in wering orthodontic hedger. Am J Orthod. 1979;75: Egolf RJ, BeGole EA, Upshw HS. Fctors ssocited with orthodontic ptient complince with introrl elstic nd hedger wer. Am J Orthod Dentofcil Orthop. 1990;97: El-Mngoury NH. Orthodontic coopertion. Am J Orthod. 1981;80: Eyuboglu S, Bengi AO, Gurton AU, Akın E. Asymmetric mxillry first molr distliztion with the trnspltl rch. Turk J Med Sci. 2004;34: Blechmn AM. Mgnetic force systems in orthodontics. Clinicl results of pilot study. Am J Orthod. 1985;87: Ginelly AA, Vits AS, Thoms WM. The use of mgnets to move molrs distlly. Am J Orthod Dentofcil Orthop. 1989;96: Ginelly AA, Vits AS, Thoms WM, Berger DG. Distliztion of molrs with repelling mgnets. J Clin Orthod. 1988;22: Bondemrk L, Kurol J. Distliztion of mxillry first nd second molrs simultneously with repelling mgnets. Eur J Orthod. 1992;14: Chcons SJ, Cputo AA, Hrvey K. Orthodontic force chrcteristics of open coil spring. Am J Orthod. 1984;85: Ginelly AA, Bednr J, Dietz VS. Jpnese NiTi coils used to move molrs distlly. Am J Orthod Dentofcil Orthop. 1991;99: Klr V. The K-loop molr distlizting pplince. J Clin Orthod. 1995;29: Loctelli R, Bednr J, Dietz VS, Ginelly AA. Molr distliztion with superelctic NiTi wire. J Clin Orthod. 1992;26: Muse DS, Fillmn MJ, Emmerson WJ, Mitchell RD. Molr nd incisor chnges with Wilson rpid molr distliztion. Am J Orthod Dentofcil Orthop. 1993;104: Jones RD, White JM. Rpid Clss II molr correction with n open-coil jig. J Clin Orthod. 1992;26: Brickmn CD, Sinh PK, Nnd RS. Evlution of the Jones jig pplince for distl molr movement. Am J Orthod Dentofcil Orthop. 2000;118:

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