Dental arch response to Haas-type rapid maxillary expansion anchored to deciduous vs permanent molars: A multicentric randomized controlled trial

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1 Originl Article Dentl rch response to Hs-type rpid mxillry expnsion nchored to deciduous vs permnent molrs: A multicentric rndomized controlled tril Alessndro Ugolini ; Crmen Cerruto b ; Luc Di Vece c ; Luis Hunc Ghislnzoni d ; Chirell Sforz e ; Tizin Doldo f ; Armndo Silvestrini-Bivti g ; Alberto Cprioglio h ABSTRACT Objective: To ssess mxill nd mndibulr rch widths response to Hs-type rpid mxillry expnsion (RME) nchored to deciduous vs permnent molrs on children with unilterl posterior crossbite. Mterils nd Methods: Seventy ptients with unilterl posterior crossbite recruited t the Universities of Genov, Sien, nd Insubri (Vrese) were rndomly locted into GrE (RME on second deciduous molrs) or Gr6 (RME on first permnent molrs) nd compred. Results: Upper intermolr distnce nd permnent molr ngultion incresed significntly in Gr6 vs GrE t T1. Upper intercnine distnce incresed significntly in GrE vs Gr6 t T1 nd T2. GrE showed significnt increses for upper intermolr nd upper intercnine widths. Gr6 showed sttisticlly significnt increses for upper intermolr widths, for upper nd lower intercnine widths, nd for increses of ngultion of upper nd lower permnent molrs. Conclusions: GrE showed reduced molr ngultion increses t T1 nd reduced molr ngultion decreses t T2 when compred with Gr6. At T2, the net increse of the upper intercnine distnce in GrE ws still significnt compred with Gr6, indicting more stble expnsion in the nterior re. (Angle Orthod. 2015;85: ) KEY WORDS: Rpid mxillry expnsion; Multicentric rndomized tril; Three-dimensionl; Deciduous vs permnent molrs Reserch Fellow, Deprtment of Orthodontics, University of Geno, Itly. b Privte prctice, Sien, Itly. c Reserch Fellow, Tuscn School of Dentl Medicine, University of Sien, Itly. d Reserch Fellow, Deprtment of Biomedicl Sciences for Helth, Università degli Studi di Milno, Milno, Itly. e Professor, Deprtment of Biomedicl Sciences for Helth, Università degli Studi di Milno, Milno, Itly. f Professor, Tuscn School of Dentl Medicine, University of Sien, Itly. g Professor, Deprtment of Orthodontics, University of Geno, Itly. h Professor, Deprtment of Orthodontics, University of Insubri, Vrese, Itly. Corresponding uthor: Dr Alessndro Ugolini, Deprtment of Orthodontics, University of Geno, Lrgo Rosnn Benzi 10, Pd. IV Genov, Itly (e-mil: lexugolini@yhoo.it) Accepted: August Submitted: April Published Online: October 14, 2014 G 2015 by The EH Angle Eduction nd Reserch Foundtion, Inc. INTRODUCTION Posterior crossbite is common clinicl condition often ssocited with trnsverse mxillry deficiency nd functionl mndibulr shift. This frequent mlocclusion is not self-correcting nd cn led to the development of crniofcil symmetries nd mndibulr dysfunction. 1 3 The effects of rpid mxillry expnsion (RME) on the mxillry complex hve been highly investigted, 4 reporting mximum mxillry intermolr nd intercnine width increse of 6.7 mm nd 5.3 mm, 5 respectively, when RME is bnded on upper first permnent molrs. Literture 6 lso reported cses of periodontl nd endodontic dmge on RME nchoring teeth; therefore, some uthors 7 10 hve suggested bnding RME on primry teeth nd reporting lso different men intermolr ( mm) 8,10 nd intercnine width increses (5 5.9 mm). 8, DOI: /

2 MULTICENTRIC RCT ON RME ANCHORED TO DECIDUOUS VS PERMANENT 571 Tble 1. Inclusion Criteri Ptients in mixed dentition Unilterl posterior crossbite t lest of the first permnent molr Upper deciduous second molrs vilble s RME nchoring teeth Subjects before the pubertl pek (CVM 1 3) 5 The deciduous molr ws considered vilble s nchoring tooth when the root hd the sme length s the clinicl crown t the orthopntomogrm rx exmintion. Few studies hve investigted the chnges in molr dentl tipping nd inclintions (on verge from 3u up to 16.7u) 9,11 following RME but comprised difficult (ie, brium sulfte solution) 12 nd more invsive exmintions such s computed tomogrphy nd cone bem computed tomogrphy (CBCT). 13,14 Few rticles 8,15 17 concerning the indirect effects on mndibulr rch following RME 11,18 20 reported low but sttisticlly significnt increse of lower intermolr ( mm) 20 nd intercnine width (0.9 mm). 8,20 Since no studies in the literture hve nlyzed the differences in permnent vs primry molrs s nchoring teeth for RME, the decision to bnd the permnent deciduous molrs did not follow clinicl protocol, but n individul decision ws mde for ech ptient bsed on clinicin experience. The im of the current study ws to evlute mxillry nd mndibulr rch widths response to RME when it is nchored to the upper second deciduous molrs or to the upper first permnent molrs nd to crete decision-mking protocol for RME therpy in mixed-dentition ptients. MATERIALS AND METHODS The design of this study ws first pproved by the Institutionl Ethicl Review Bord of the Universities of Genov, Sien, nd Insubri (Vrese), Itly. Eightyeight consecutive children presenting unilterl posterior crossbite were recruited in the corresponding three deprtments of orthodontics. The inclusion nd primry nd secondry exclusion criteri re shown in Tbles 1 nd 2. The finl smple of ptients comprised 70 subjects (31 boys nd 39 girls; men ge, yers) in Clss I or Clss II dentl mlocclusion with ANB,5u. Subjects were rndomly ssigned to group GrE (RME on second deciduous molrs; Figure 1) or Gr6 (RME on first permnent molrs; Figure 1b) by using strtified blocked rndomiztion with rndom block sizes performed by n electronic computer progrm. Ptients were lso strtified ccording to ge nd gender. The treting clinicin ws blinded from the rndomiztion procedure, but becuse of cler differences in pplince design, blinding ws not possible during the tretment period. The cst exminer ws lso blinded from the tretment protocol. Tble 2. Exclusion Criteri nd Number of Ptients No. of Ptients Initil smple 88 Primry exclusion criteri Previous orthodontic tretment 0 Hypodonti in ny qudrnt excluding third molrs 2 Indequte orl hygiene 3 Temporomndibulr joint disorders 2 Crniofcil bnormlities 2 Secondry exclusion criteri Lck of records 1 Loss of lower E nd need for lingul rch, lip bumper, or spce mintiner 2 Lck of consensus 3 Need for other orthodontic tretment during rpid mxillry expnsion 3 Finl smple 70 In GrE or Gr6, when RME ws in situ, ptients strted the screw ctivtion (Snp-lock expnder screw, Forestdent, Pforzheim, Germny) of one-qurter turn dy (0.22 mm) until overcorrection ws chieved (ie, the occlusl surfce of the first mxillry pltl cusp contcted the occlusl surfce of the mndibulr first molr fcil cusp), nd the RME remined in plce for 10 months. The screw ws turned for dys for GrE nd for 6 6 dys for Gr6, nd the verge tretment time ws months. Dentl csts were tken t T0 (before the tretment) nd t T1 (5 months fter the end of the ctive tretment, with RME in situ in GrE to void second deciduous molr exfolition nd with RME temporrily removed for the impression in Gr6) nd t T2 (5 months fter T1), ccording to the protocol by Cozzni et l. 8 The men ge of the ptients t T0, T1 nd T2 is reported in Tble 3. Mesurements on 3D Dentl Csts The mxillry nd mndibulr csts were processed by three-dimensionl (3D) scnner (NextEngine, Inc, Snt Monic, Clif), nd lndmrks were trced by mens of Geomgic 3D Softwre (Reserch Tringle Prk, Durhm, NC). Mesurements were subsequently clculted directly on scnned dentl csts by mens of Figure 1. () Hs-type RME bnded on upper second deciduous molrs. (b) Hs-type RME bnded on upper first permnent molrs.

3 572 UGOLINI, CERRUTO, DI VECE, GHISLANZONI, SFORZA, DOLDO, SILVESTRINI-BIAVATI, CAPRIOGLIO Tble 3. Ptient Ages in the Two Anlyzed Study Groups Smple, n Men, y SD Minimum Mximum GrE T0 T1 T2 Gr6 T0 T1 T2 d hoc softwre. If cusp tips were worn, the centers of the resulting fcets were used s lndmrks. Pltl nd lingul mesurements for mxillry nd mndibulr intermolr width were mde t the point of intersection of the pltl or lingul groove with the cervicl gingivl mrgin (Figure 2,b, line 1) ccording to McDougll et l.21 The upper nd lower occlusl vestibulr intermolr width ws mesured s the distnce between mesiobuccl cusps tips of the first permnent molrs bilterlly nd the upper nd lower intercnine width s the distnce between cusp tips bilterlly (Figure 2, b, lines 2 nd 3). Two points per teeth were llowed to trce the fcil xis of the clinicl crown (FACC) of the first molrs nd deciduous cnines t T0, T1, nd T2 (Figure 3). Also, three lingul or pltl points (interincisl ppill; right nd left molr points t the intersection of the tooth nd gingivl mrgin between the two cusps) were used s reference to trce plne22 (Figure 4,b). The ngles between FACC nd this reference plne were then mesured. These ngles corresponded to crown ngultion on reference plne (Figure 5,b), nd their clinicl equivlent ws the torque of the crown.23 Sttisticl Anlysis Method error. To stndrdize mesurements, dt were collected by the principl investigtor nd checked by nother senior clinicin. Mesurements Figure 2. () Mxillry 3D dentl cst. (b) Mndibulr 3D dentl cst. Line 1 5 pltl mxillry nd lingul mndibulr intermolr width; line 2 5 mxillry nd mndibulr vestibulr intermolr width; line 3 5 mxillry nd mndibulr intercnine width. Figure 3. FACC of the upper right first permnent molr nd upper right deciduous cnine. nd lndmrk loction were repeted (3 dys fter the first mesurement) on 25 rndomly selected csts to determine the error of method. Dhlberg s vlues method error24 (inter- nd intropertor) ws performed nd rnged from 0.17 to 0.53 mm (not significnt). Also, intrclss correltion coefficients25 were clculted, nd ll vlues were lrger thn.95. Stndrd devitions between repeted mesurements were found to be in the rnge of 0.08 to 0.17 mm for ll mesurements nd of 0.09u to 0.2u for ngulr mesurement. Overll, the method error ws considered negligible. Descriptive sttistics were computed for ll nlyzed vribles (Tbles 3, 4 nd 5). Shpiro-Wilks test showed tht dt were normlly distributed (W in Tbles 4 nd 5). A one-wy repetedmesures nlysis of vrince (ANOVA; T0, T1, nd T2 were the independent vribles) ws used to find sttisticlly significnt differences for the vribles nlyzed in the sme group (widths nd ngultions). When sttisticlly significnt difference ws found, post hoc test (Bonferroni corrected) ws performed. In Tble 6, GrE nd Gr6 chnges t T1 nd t T2 were compred using Student s t-tests. Probbilities of less thn.05 were ccepted s significnt in ll sttisticl nlyses (P,.05). Smple size ws clculted priori bsed on primry outcome (molr expnsion, s continuous Figure 4. () Tringulr reference plne for crown ngultion in mxillry 3D dentl cst. (b) Tringulr reference plne for crown ngultion in mndibulr 3D dentl cst.

4 MULTICENTRIC RCT ON RME ANCHORED TO DECIDUOUS VS PERMANENT 573 Figure 5. () Crown ngultions of 1.6, 2.6, 5.3, nd 6.3 in the mxillry 3D dentl csts. (b) Crown ngultions of 3.6, 4.6, 7.3. nd 8.3 in the mndibulr 3D dentl csts. outcome) to obtin sttisticl power of the study greter thn 0.85, using the men vlues nd stndrd devitions of mxillry molr expnsion fter RME therpy found by Cozzni et l., 8 t 5.05 nd b 5.2). Bsed on these prmeters, to hve n 85% chnce of detecting s significnt (t the two-sided 5% level) five-point difference between the two groups, with n ssumed stndrd devition of 20 nd loss to follow-up of 20%, the smple size required ws 30 ptients in ech group. The effect size (ES) coefficient (d) 26 ws lso clculted. An ES of.2 to.3 might be smll effect nd thus smll cliniclly significnt difference, bout.5 medium effect, nd 0.8 to infinity lrge effect. RESULTS Clinicl crossbites were entirely corrected in 100% of the cses t T1 nd t T2. At T2 in GrE, during the pplince debonding, 6 (8%) second deciduous molrs were lost (removed with the RME). No differences between GrE nd Gr6 were found t T0 for ge, sex distribution, or for the vribles regrding dentl mesurements. At T1, there were no sttisticl differences (P 5.4) for the screw ctivtion between the groups. Both ANOVA for GrE (Tble 4) nd ANOVA for Gr6 (Tble 5) showed sttisticlly significnt increse between T0 T1 nd T0 T2 for upper intermolr vestibulr nd pltl widths nd for upper intercnine width. Moreover, sttisticlly significnt increse of the ngultion of the upper right nd left first permnent molrs, of the lower intercnine distnce, nd of 3.6 nd 4.6 ngultions ws lso found in Gr6. When GrE ws compred with Gr6 (Tble 6), t T1, there were sttisticlly significnt lrger increments of upper intermolr vestibulr nd pltl distnces s well s of upper first right nd left molr ngultions in GR6 thn GrE. The ES ws smll for upper intermolr vestibulr nd pltl distnce nd medium for 1.6 nd 2.6 ngultion. There ws lso sttisticlly significnt lrger increse of upper intercnine distnce of 1.8 mm (P 5.005) in GrE compred with Gr6. The ES ws lrge. At T2, GrE showed sttisticlly significnt lrger increse of upper intercnine distnce of 1.6 mm (P 5.02) in comprison with Gr6 ptients. The ES result ws medium. DISCUSSION All subjects were selected before the pubertl pek (CVM 1 3). In these three stges, RME ptients exhibit significnt nd more effective long-term chng- Tble 4. Dentl Arch Distnces (Unit: mm) nd Crown Angultions (Unit: u) in GrE Ptients T0 T1 T2 Comprisons GrE Men SD Men SD Men SD P ANOVA Post Hoc Tests Mxill Intermol vestib dist ,.01** T0 vs T1 T0 vs T2 Intermol plt dist ,.01** T0 vs T1 T0 vs T2 Intercn dist ,.01** T0 vs T1 T0 vs T2 1.6 Angultion Angultion Angultion Angultion Mndible Intermol vestib dist Intermol ling dist Intercn dist Angultion Angultion Angultion Angultion ANOVA for GrE. Post hoc tests (Bonferroni corrected) re reported for vribles with sttisticlly significnt difference found by ANOVA. ** P,.01.

5 574 UGOLINI, CERRUTO, DI VECE, GHISLANZONI, SFORZA, DOLDO, SILVESTRINI-BIAVATI, CAPRIOGLIO Tble 5. Dentl Arch Distnces (Unit: mm) nd Crown Angultions (Unit: u) in Gr6 Ptients T0 T1 T2 Comprisons Gr6 Men SD Men SD Men SD P ANOVA Post Hoc Tests Mxill Intermol vestib dist ,.01** T0 vs T1 T0 vs T2 Intermol plt dist ,.01** T0 vs T1 T0 vs T2 Intercn dist ,.01** T0 vs T1 T0 vs T2 1.6 Angultion * T0 vs T1 2.6 Angultion ,.01** T0 vs T1 T0 vs T2 5.3 Angultion Angultion Mndible Intermol vestib dist Intermol ling dist Intercn dist ,.01** T0 vs T2 3.6 Angultion * T0 vs T2 4.6 Angultion * T0 vs T2 7.3 Angultion Angultion ANOVA for Gr6. Post hoc tests (Bonferroni corrected) re reported for vribles with sttisticlly significnt difference found by ANOVA. * P,.05; ** P,.01. es t the skeletl level in both mxillry nd circummxillry structures. 27 Between T0 nd T1, there ws significnt lrger increse of upper intermolr vestibulr nd pltl width together with lrger increse of 1.6 nd 2.6 ngultion in Gr6 vs GrE ptients. Ptients in GrE showed insted trend of reduced ngultion increses of 1.6 nd 2.6 t T1 nd reduced ngultion decreses of the sme teeth t T2. This is in ccordnce with Asnz et l., 28 who ssessed tht bnded RME will produce tipping of the nchor tooth (n verge of 3u) insted of true skeletl expnsion, lthough this tipping is not considered cliniclly significnt. Ferrrio et l. 11 found 17.6u of molr vestibulr inclintion increse, but tht ws due to the use of the less rigid NiTi pltl expnder. In our study, we found lso smll ES nd thus smll clinicl significnce. Moreover, t T2, the significnt difference for the increse of 1.6 nd 2.6 ngultion between Gr6 nd GrE disppered, thus indicting the sme expnsion conditions for both groups t the end of tretment. In GrE, the molr width increse is minly relted to the ctul molr expnsion (85%), nd only minor percentge ws relted to the ngultion Tble 6. Comprison of Dentl Arch Distnces nd Crown Angultions in Gr6 vs GrE Ptients in the Two Anlyzed Time Points T1 T2 P Vlue Effect Size P Vlue Effect Size Mxill Intermolr vestibulr distnce.04*.4 S.56 Intermolr pltl distnce.03*.4 S.07 Intercnine distnce.005**.8 L.02*.6 M 1.6 Angultion.04*.5 M Angultion.03*.5 M Angultion Angultion Mndible Intermolr vestibulr distnce Intermolr lingul distnce Intercnine distnce Angultion Angultion Angultion Angultion Student s t-test for independent smples. Effect size S indictes smll clinicl significnce; M, medium clinicl significnce, L, lrge clinicl significnce. * P,.05; ** P,.01.

6 MULTICENTRIC RCT ON RME ANCHORED TO DECIDUOUS VS PERMANENT 575 Figure 6. Lower increse molr ngultion between T0 nd T2. increse (15%). On the opposite, in Gr6, ngultion produced 45% of the molr expnsion. At T1 nd T2, we lso found significnt lrger increse of upper intercnine width in GrE vs Gr6 ptients, which ws not ssocited with differences in the increse of upper cnine ngultion. These results suggest better nd more stble expnsion in the nterior re in GrE, probbly due to more nterior position of the screw. Regrding the lower rch, between T0 nd T2, for both groups there ws generl tendency of increse of lower molr nd cnine vlues together with increse of lower intermolr nd intercnine widths, but no sttisticlly significnt differences between GrE nd Gr6 were found, in ccordnce with Cozzni et l. 8 Between T0 T1 nd T0 T2, GrE ptients showed sttisticlly significnt increse of upper intermolr vestibulr nd lingul widths together with intercnine width. There ws no sttisticlly significnt increse of the ngultion of 1.6, 2.6, 5.3, or 6.3, thus indicting no dentl tipping nd dentolveolr compenstion. Although there ws generl tendency of expnsion of the lower rch, no sttisticlly significnt differences were found regrding the vribles for the lower rch in GrE. In Gr6 ptients, sttisticlly significnt increses of upper intermolr vestibulr nd lingul widths together with intercnine width were observed between T0 T1 nd T0 T2. In this cse, there ws lso significnt increse of the ngultion of 1.6 nd 2.6, indicting dentl tipping nd dentolveolr compenstion. 11,29 In contrst with previous investigtions, the present study did not find ny sttisticlly significnt increse of lower intermolr width but rther significnt increse of lower 3.6 nd 4.6 ngultion (+6.8u, 2.9u right nd 3.9u left) in Gr6 between T0 nd T2 (Figure 6). This chnge ws probbly due to occlusl chnges following ngultion increse so tht the resultnt force vector cting on the mndibulr teeth (especilly molrs) ws more vestibulr directed, becuse the occlusl spect of the lingul cusp of upper first molrs contcted the occlusl spect of the fcil cusp of the lower first molrs, s stted by Hs. 18 Hs 18 lso ssocited these chnges to the lip bumper effect ; tht is, the lterl movement of the mxille widened the re of ttchment of the buccl musculture. In Gr6, significnt increse of lower intercnine width (men of 1.8 mm) between T0 nd T2 ws lso found, in ccordnce with previous studies. 8,17,18 Two long-term retrospective trils reported the chnges in untreted (Clss I or Clss II mlocclusion but not crossbite) control groups. 29,30 They found reduction in mndibulr rch perimeter, minly relted to the exfolition of the mndibulr second deciduous molrs; slight decrese in intercnine width; nd very little or no increse in molr width. For ethicl resons, it ws not possible to ssemble control group, since the crossbite is not self-correcting sitution. Moreover, emphsis ws given to two different clinicl procedures, nd this ws mde with longitudinl design, in which ech ptient ws his or her own control. In our study, custom-designed digitl procedure ws used to evlute tooth ngultion mesurements. Bsed on our previous investigtion, 23 this procedure showed good results in terms of reproducibility nd relibility of the method, compred with other questionble methods to mesure ngultion of the crowns (eg, mnul protrctor, trimming models) Nevertheless, further comprisons between this method nd new modern (but more invsive) mesurement methods, such s CBCT, my help to confirm the effective reproducibility nd relibility of the custom-designed digitl procedure. Although the literture considers retention period of 6 months sufficient for ptients undergoing RME tretment during their CVM 1 3, 31,32 our procedure reveled interesting clinicl spects such s the stbility of upper second deciduous molrs in GrE: t T1, no nchoring teeth were lost, nd t T2, only smll percentge (8%) of the nchoring deciduous molrs remined ttched to the bnds of RME. Therefore, our inclusion criteri of vilbility of the second deciduous molrs through orthopntomogrm exmintion could be tken s clinicl reference in the evlution of nchoring RME on deciduous teeth for n RME tretment of unilterl posterior crossbite. CONCLUSIONS N GrE ptients show reduced molr ngultion increses t T1 nd reduced molr ngultion decreses t T2 (ie, less dentl compenstion) when

7 576 UGOLINI, CERRUTO, DI VECE, GHISLANZONI, SFORZA, DOLDO, SILVESTRINI-BIAVATI, CAPRIOGLIO compred with Gr6 ptients. Moreover, t T2, the net increse of mxillry intercnine distnce in GrE is still significnt compred with Gr6, indicting more stble expnsion on the nterior region of the rch. N Trnsverse mxillry deficiency cn be successfully corrected with RME on upper second deciduous molrs, voiding undesirble periodontl effects on permnent teeth when RME is nchored on the upper first permnent molrs. N RME nchored on second deciduous molrs ws cliniclly efficient when the root of the nchoring tooth hd t lest the sme length of the clinicl crown t the orthopntomogrm rx exmintion. REFERENCES 1. McNmr J Jr. Mxillry trnsverse deficiency. Am J Orthod Dentofcil Orthop. 2000;117: Thilnder B, Whlund S, Lennrtsson B. The effect of erly interceptive tretment in children with posterior cross-bite. Eur J Orthod. 1984;6: Sntos Pinto A, Buschng PH, Throckmorton GS, Chen P. 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