Comparison of two early treatment protocols for anterior dental crossbite in the mixed dentition: A randomized trial

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1 Originl Article Comprison of two erly tretment protocols for nterior dentl crossbite in the mixed dentition: A rndomized tril Cristin B. Mimoto ; Lendro S. Mrques b ; Lucs G. Abreu c ; Sul M. Piv c ABSTRACT Objective: To evlute nd compre two tretment protocols to correct nterior dentl crossbite in the mixed dentition. Mterils nd Methods: Thirty children, 8 10 yers of ge, prticipted. Individuls were divided into two groups. Group 1 consisted of 15 children treted with n upper removble pplince with finger springs; group 2, 15 children treted by bonding resin-reinforced glss ionomer cement bite pds on the lower first molrs. The 30 prticipnts were evluted before tretment (T1) nd 12 months fter tretment begn (T2). The vribles evluted included overjet, perimeter of the mxillry rch, intercnine distnces in the mxill nd mndible, SNA, SNB, ANB, nd U1.NA. Dt nlysis included descriptive sttistics, pired t-test nd Student s t-test. Effect sizes nd confidence intervls were lso clculted. Results: Group 1 showed significnt increse in overjet (P,.001), intercnine distnce in the mxill (P ¼.006), intercnine distnce in the mndible (P ¼.031), nd U1.NA (P ¼.002). Group 2 showed significnt increse in overjet (P ¼.008), intercnine distnce in the mndible (P ¼.005), nd U1.NA (P,.001). For ll the evluted vribles, no sttisticlly significnt differences were observed between the two groups. Conclusions: No significnt differences were observed between the two protocols: use of removble mxillry biteplte with finger springs nd bonding of resin-reinforced glss ionomer cement bite pds on the lower first molrs, for the correction of nterior crossbite in the mixed dentition. (Angle Orthod. 0000;00: ) KEY WORDS: Child; Mlocclusion; Anterior crossbite; Mixed dentition; Interceptive orthodontics INTRODUCTION PhD Student, Deprtment of Peditric Dentistry nd Orthodontics, Universidde Federl de Mins Geris, Belo Horizonte, MG, Brzil. b Professor, Deprtment of Peditric Dentistry, Universidde Federl dos Vles do Jequitinhonh e Mucuri, Dimntin, MG, Brzil. c Professor, Deprtment of Peditric Dentistry nd Orthodontics, Universidde Federl de Mins Geris, Belo Horizonte, MG, Brzil. Corresponding uthor: Dr Lucs Guimrães Abreu, Deprtment of Peditric Dentistry nd Orthodontics, Universidde Federl de Mins Geris, Ru Mrnhão 1447 / 1101, Funcionários, Belo Horizonte, MG, Brzil (e-mil: lucsgbreu01@gmil.com) Accepted: September Submitted: My Published Online: November Ó 0000 by The EH Angle Eduction nd Reserch Foundtion, Inc. Anterior crossbite is defined s mlocclusion in the sgittl dimension resulting in lingul position of the mxillry nterior teeth in reltion to the mndibulr nterior teeth. It hs gret clinicl significnce tht is both esthetic nd functionl. 1 It cn be found in the deciduous, mixed, nd permnent dentitions. Bsed on the individul presenttion, n nterior crossbite cn be dentl, functionl, or skeletl. In the literture, the prevlence of ll types of nterior crossbite vries from 2.2% to 11.9%, depending on whether the edge-toedge reltionship of the incisors is considered nd on the rcil chrcteristics of the individuls evluted. 2 Anterior crossbite occurs becuse of chnge in the vestibulr-lingul reltionship of one or more nterior teeth, with the mxillry incisor(s) lingully positioned nd the mndibulr teeth more fcil. It hs been reported tht trumtic occlusion my be present nd, if this problem does not receive erly tretment, tht it DOI: /

2 2 MIAMOTO, MARQUES, ABREU, PAIVA my result in periodontl problems in the mndibulr incisors, 3 the occurrence of pin, chnges in the nterior-posterior positioning of the mndible, nd development of problems in the temporomndibulr joint (TMJ). 4,5 Interceptive orthodontic tretment is defined s ny procedure tht elimintes or reduces the severity of developing mlocclusion. 2 Such n intervention during the mixed dentition my llow the clinicin to correct n nterior crossbite, thus fvoring more hrmonious growth of the bones 6 8 nd perhps preventing the crossbite to persist in the permnent dentition. In this sense, when the orthodontist cts in n interceptive mnner, comprehensive orthodontic tretment with fixed pplinces my be simplified or reduced. 9 A wide rnge of tretment protocols cn be used to correct n nterior crossbite in the mixed dentition. 2 However, there is little evidence to indicte which tretment method is the most efficient. 10 Therefore, the present study imed to compre two of these protocols: n upper removble pplince with finger springs nd the bonding of resin-reinforced glss ionomer cement bite pds on the lower first molrs. The null hypothesis ws tht the erly tretment of nterior crossbite with either of these two protocols is eqully efficient. MATERIALS AND METHODS This study is reported ccording to the Consolidted Stndrds of Reporting Trils (CONSORT) guidelines. 11 Prticipnts, Study Loction, nd Eligibility Criteri The smple consisted of 30 individuls 8 10 yers of ge who presented with nterior crossbite in the mixed dentition. The prticipnts were divided into two groups. Group 1 consisted of 15 children who were treted with n upper removble pplince with finger springs. Group 2 consisted of 15 children treted by bonding resin-reinforced glss ionomer cement bite pds on the lower first molrs. The distribution of the 30 individuls into the two groups ws performed in rndomized mnner s follows: seled envelope ws prepred with 30 crds contining the nmes of the two tretment protocols on 15 crds ech. For ech prticipnt, one crd ws drwn from the envelope to indicte to which group the ptient would be ssigned. This process ws crried out by n ssistnt until ll ptients hd been plced in group. The 30 children were treted by one orthodontist. The smple ws selected from the medicl records of ptients receiving tretment t the Children s Clinic of the Federl University of the Vlleys of Jequitinhonh nd Mucuri (UFVJM), Dimntin, Brzil. The study included individuls from 8 to 10 yers of ge who presented with n nterior crossbite in the mixed dentition with ll four permnent first molrs erupted nd t lest one permnent incisor in crossbite. Exclusion criteri were (1) ny compromised condition of the child s overll helth (including crniofcil nomlies nd cognitive disorders) ccording to the child s medicl record nd physicl exmintion s reported by the prents, (2) children with functionl crossbites, (3) individuls with skeletl nterior crossbites (ANB,08) or posterior crossbite ssocited with the nterior crossbite, (4) children with sucking hbits or cesstion of sucking hbit within less thn 1 yer, nd (5) individuls with prior history of orthodontic tretment. Ethicl Considertions The study ws pproved by the UFVJM Humn Reserch Ethics Committee (protocol ). The children nd their gurdins were informed bout the objectives of the study nd tht their prticiption ws voluntry. For those greeing to prticipte, the children nd their gurdins signed n informed consent form. After 12 months of follow-up, the children who did not exhibit full correction of the nterior crossbite either continued in tretment or underwent new type of tretment. Smple Clcultion Considering n lph significnce level ¼ 0.05 nd sttisticl power of 95%, the study required t lest nine individuls in ech group to detect n verge difference of 2.0 mm (63.0) in overjet between the tretment protocols. To compenste for possible losses, six dditionl prticipnts were included in ech group. Therefore, there were 15 individuls ssigned to ech group (Figure 1). Upper Removble Applince with Finger Springs The device hd two Adms clsps on the permnent first molrs, two rrow clsps between the deciduous molrs, nd double finger spring dpted to the pltl surfces of the teeth to be uncrossed, in ddition to the lbil bow. The posterior region included n occlusl splint in n ttempt to obtin sufficient disocclusion to llow for moving the teeth in crossbite. The ptients were dvised to remove the pplince only to et or during orl hygiene. Resin-reinforced Glss Ionomer Cement Bite Pds Resin-reinforced glss ionomer cement bite pds (Riv Light Cure, Byswter, Austrli) were plced on the occlusl surfce of the mndibulr permnent first

3 EARLY TREATMENT OF ANTERIOR CROSSBITE IN THE MIXED DENTITION 3 Figure 1. Flow chrt of the study. molrs. These devices were thick enough to disclude ll the nterior teeth, which llowed enough spce for the movement of the teeth in crossbite by tongue pressure. Appointments were scheduled every 3 4 weeks for ptients in both groups. Tretment for the 30 prticipnts ws conducted by n orthodontic specilist. Evluted Vribles The ssessor of the outcomes ws blinded. The 30 prticipnts were evluted before tretment (T1) nd 12 months fter implementtion of the protocols (T2). The following outcomes were mesured on study csts: Overjet (Correction of the Crossbite) The therpeutic effect of the two tretment protocols ws evluted, using metl ruler, by mesuring the overjet increse in millimeters, tht is, the difference of overjet between T1 nd T2. Perimeter of the Mxillry Arch Evlution of the mxillry rch perimeter ws performed with n initil nd finl plster model using brss wire, beginning t the distl surfce of the deciduous second molr (or the mesil surfce of the permnent first molr), pssing round the rch over the contct points of the posterior teeth nd incisl edges of the nterior teeth to the distl surfce of the Angle Orthodontist, Vol 00, No 0, 0000

4 4 MIAMOTO, MARQUES, ABREU, PAIVA Tble 1. Chrcteristics of the Children in Both Groups nd Intergroup Comprisons Group 1 Group 2 Intergroup Comprison Number (%) Number (%) (P Vlue) Gender Boys 11 (73.3) 07 (46.7) 0.264* Girls 04 (26.7) 08 (53.3) Crowding No 05 (33.3) 08 (53.3) 0.462* Yes 10 (66.7) 07 (46.7) Full crossbite correction No 07 (46.7) 07 (46.7) 0.999* Yes 08 (53.4) 08 (53.3) Men (SD ) Men (SD) Children s ge (yers) 9.07 (0.79) 9.00 (0.84) 0.826** Number of teeth crossed 1.60 (1.06) 1.67 (0.61) 0.834** SD indictes stndrd devition. * Person chi-squre test. ** Student s t-test. deciduous second molr (or the mesil surfce of the permnent first molr) on the opposite side. 12 The increse in rch perimeter ws clculted by the difference between the perimeter of the rch in T1 nd T2. Intercnine Distnce The intercnine distnce in the mxill nd mndible ws mesured with digitl cliper (Digitl 6, 8M007906, Muser-Messzeug GmbH, Oberndorf/ Neckr, Germny) s the shortest liner distnce between the cnine cusp tips on the plster models. Intercnine expnsion ws clculted by the difference between the intercnine distnces t T1 nd T2. 13 Cephlometric Anlysis The cephlometric ngles evluted were SNA, SNB, nd ANB, to evlute the position of the mxill nd mndible reltive to the crnil bse nd the Tble 2. Comprison of Pretretment Mesures Between Groups Group 1 Group 2 Men (SD) Men (SD) P Vlue* Overjet 1.13 (0.35) 1.27 (0.45).379 Arch perimeter (6.61) (5.24).506 Dist IC (Mx) (2.12) (3.52).496 Dist IC (Md) (2.04) (2.57).051 SNA (3.74) (4.41).805 SNB (3.76) (4.36).961 ANB 3.80 (1.74) 3.35 (2.75).600 U1.NA (4.88) (6.11).671 Indictes mxillry rch perimeter; Dist IC (Mx), intercnine distnce in the mxill; Dist IC (Md), intercnine distnce in the mndible; SD, stndrd devition. * Indictes Student s t-test. Significnce level of P,.05. position of the mxill nd mndible to ech other. The upper incisor inclintion (U1.NA) ws lso evluted. The chnge in cephlometric ngles ws determined by the difference in the vlues between T1 nd T2. Sttisticl Anlysis Sttisticl nlysis ws conducted using the Sttisticl Pckge for the Socil Sciences (SPSS for Windows, version 17.0, SPSS Inc, Chicgo, Ill). Appliction of the Shpiro-Wilk test demonstrted tht the dt were normlly distributed. Therefore, prmetric tests were used. The nlysis of the dt included descriptive tests (chi-squre nd Student s t- test) to chrcterize the smple. Pired t-tests were used to evlute the effects (chnges occurring during tretment, T2 T1) of the two tretment protocols for correcting nterior crossbite. A Student s t-test ws used to compre the chnges occurring during tretment (T2 T1) between the two groups. Vlues of P,.05 were considered sttisticlly significnt. Effect sizes with 95% confidence intervls were lso clculted by dividing the difference between the mens of both groups by the pooled stndrd devition. 14,15 Effect sizes were interpreted ccording to the following vlues: 0.20, smll; 0.50, medium; nd 0.80, lrge. 14 RESULTS The verge ge of the children in group 1 ws 9.07 yers (60.79), while in group 2, it ws 9.00 yers (60.84). Chrcteristics of the prticipnts nd intergroup comprisons re described in Tble 1. Comprison of the pretretment mesures between groups is displyed in Tble 2. Tble 3 shows the effects (T2 T1) of the two tretment protocols for correcting the nterior crossbite. Group 1 showed significnt increse in overjet (P,.001), mxillry intercnine distnce (P ¼.006), mndibulr intercnine distnce (P ¼.031), nd upper incisor inclintion (P ¼.002). Group 2 showed significnt increse in overjet (P ¼.008), mndibulr intercnine distnce (P ¼.005), nd upper incisor inclintion (P,.001). Tble 4 compres the chnges during tretment between the two protocols nd the effect sizes. No sttisticlly significnt differences were observed between the two groups for ny of the vribles evluted. DISCUSSION The orthodontic literture on erly tretment protocols for nterior crossbite hs been sprse. Recently, systemtic review suggested tht clinicl trils should be conducted to evlute the efficiency of different tretment protocols for this type of mlocclusion. 2 Tking into ccount the lck of sttisticlly significnt

5 EARLY TREATMENT OF ANTERIOR CROSSBITE IN THE MIXED DENTITION 5 Tble 3. Effects of the Two Tretment Protocols in Correcting Anterior Crossbite Group 1 Group 2 Men (SD) T1 Men (SD) T2 P Vlue* Men (SD) T1 Men (SD) T2 P Vlue* Overjet 1.13 (0.35) 0.27 (0.88), (0.45) 0.27 (0.96).008 Arch perimeter (6.61) (6.60) (5.24) (5.50).396 Dist IC (Mx) (2.12) (2.71) (3.52) (1.98).084 Dist IC (Md) (2.04) (2.66) (2.57) (2.37).005 SNA (3.74) (3.76) (4.41) (4.61).794 SNB (3.76) (3.69) (4.36) (4.45) ANB 3.80 (1.74) 4.09 (2.48) (2.75) 3.21 (1.46).795 U1.NA (4.88) (4.67) (6.11) (5.08),.001 Indictes mxillry rch perimeter; Dist IC (Mx), intercnine distnce in the mxill; Dist IC (Md), intercnine distnce in the mndible; SD, stndrd devition; T1, before tretment; T2, 12 months fter beginning tretment. * Pired t-test. Significnce level of P,.05. differences between protocols, the null hypothesis could not be rejected in the present study. Anterior crossbite ffecting one or more incisors ws corrected efficiently by both n upper removble pplince with finger springs nd bonded resin-reinforced glss ionomer cement bite pds on the lower first molrs. Thus, both tretment protocols could be recommended for correcting this type of mlocclusion. Consequently, this study offers relevnt informtion to prctitioners becuse erly tretment of nterior crossbite hs been widely dvocted. 16,17 The findings reported in this study showed tht both of the erly protocols investigted led to significnt increse in overjet nd mndibulr intercnine distnce fter the 12-month tretment period. Moreover, improvement in overjet nd intercnine distnce in the mndible ws not different between the upper removble pplince nd the bite pds on the lower first molrs. One prior study tht compred the efficiency of fixed pplinces nd upper removble pplinces with finger springs demonstrted tht n nterior crossbite in the mixed dentition cn lso be corrected successfully using either of those two protocols. 10 Additionlly, long-term, posttretment stbility ws similr in those two modes of tretment. For both the fixed nd the removble pplince, the success rte remined high t the 2-yer follow-up. 18 One rndomized clinicl tril tht evluted the erly correction of unilterl posterior crossbite reveled tht the success rte ws superior with fixed device (Qud-helix) compred with tretment using removble pplince with n expnsion screw. 19 The verge tretment time ws lso significntly shorter nd cheper with the bonded device. 20 This finding my be ttributed to low complince with the removble device. It is well-known tht when therpy with removble pplinces is prescribed, ptient complince is determining fctor in the efficiency of tretment. 21 The level of complince with tretment cn prtly explin the prolonged tretment time observed with removble pplinces. However, if the ptients hd cooperted, perhps there would hve been more fvorble outcome. 22 It is likely tht ptients with nterior crossbite hve greter wreness of their mlocclusion since the condition is estheticlly obvious in contrst to ptients with posterior crossbite. 18 Hence, the individuls from the current study should hve been highly motivted nd willing to comply with tretment recommendtions. Despite being nonsignificnt difference, the increse in overjet ws mrginlly higher for the Tble 4. Comprison of the Chnges During Tretment (T2 T1) Between the Two Groups Group 1 T2 T1 Group 2 T2 T1 Men (SD) Men (SD) Difference Between Groups P Vlue* Effect Size** CI (95%) Overjet 1.40 (0.91) 1.00 (1.25) Arch perimeter 0.47 (1.50) 0.47 (2.06) Dist IC (Mx) 1.40 (1.68) 1.13 (2.35) Dist IC (Md) 1.60 (2.58) 2.20 (2.56) SNA 0.74 (2.55) 0.14 (2.03) SNB 3.30 (6.68) 0.40 (1.59) ANB 0.29 (2.05) 0.14 (2.04) U1.NA 3.27 (3.41) 3.87 (3.14) indictes mxillry rch perimeter; Dist IC (Mx), intercnine distnce in the mxill; Dist IC (Md), intercnine distnce in the mndible; T1, before tretment; T2, 12 months fter beginning tretment; SD, stndrd devition; CI, confidence intervl. * Student s t-test. Significnce level of P,.05. ** Difference between mens of both groups by the pooled stndrd devition. Angle Orthodontist, Vol 00, No 0, 0000

6 6 MIAMOTO, MARQUES, ABREU, PAIVA individuls treted with the upper removble fingerspring pplince compred with those treted with the resin-reinforced glss ionomer cement bite pds. This effect size ws 0.37 mm. Indeed, tking into ccount the nlysis of the effect size, the benefit of prticulr protocol my be suggested by smll tril such s this one with nonsttisticlly significnt results. It hs been dvocted tht sttisticl outcomes give relevnt informtion but, sometimes the sttisticl significnce might not reflect the size of the tretment effect. 23 The present study hd weknesses tht should be cknowledged. This study should hve included control group of individuls with untreted nterior crossbite of the mixed dentition. 18 However, this would hve been uncceptble for ethicl resons 24 nd, lso, the use of historicl control groups hs been subject of much criticism in orthodontic reserch. 25 Second, s previously mentioned, in ny removble pplince therpy, ptient complince with tretment is significnt determinnt of tretment efficiency. Therefore, one could rgue tht the present clinicl tril my hve been sensitive to the risk of the Hwthorne effect, through which the wreness of being evluted could hve hd positive impct on childrens behvior. 26 Consequently, they my hve cooperted better with the prescribed tretment regimen. However, this tril ws strengthened by the rndom lloction of prticipnts nd the prospective longitudinl design. The former helped to minimize bis in the ssignment of individuls to ech tretment protocol, resulting in two groups tht were comprble for known or unknown confounding vribles. 27 The ltter llowed investigtion of cusl ssocitions between the interventions nd the outcome. 28 The vribles included in this study were highly relevnt mesures for evluting tretment effectiveness. 29,30 Nevertheless, it is importnt to note tht the literture hs lso dvocted tht other importnt spects of erly intervention should be evluted in mixed dentition tretment. These include cost-benefit 31 nd complictions during tretment (displcement, brekge, nd loss of pplinces), 20 in ddition to other vribles, such s the perception of pin nd discomfort ssocited with tretment. 32 Those outcomes should be nlyzed in future studies. Ptientreported mesures, such s qulity of life ssessments hve been underrepresented in orthodontic clinicl trils. Thus, future reserch should evlute individuls perceptions of the physicl nd psychologicl consequences of such orthodontic protocols. 33 Moreover, s the erly tretment of nterior crossbite is performed in individuls who re still growing, it is lso importnt to evlute the stbility fter correction nd the chnges observed from long-term perspective. 10 CONCLUSIONS No significnt differences were observed between the two protocols: use of removble mxillry biteplte with finger springs nd bonding of resinreinforced glss ionomer cement bite pds on the lower first molrs, for correcting nterior crossbite in the mixed dentition. REFERENCES 1. Tsi HH. Components of nterior crossbite in the primry dentition. ASDC J Dent Child. 2001;68: Borrie F, Bern D. Erly correction of nterior crossbites: systemtic review. J Orthod. 2011;38: Eismnn D, Pruss R. Periodontl findings before nd fter orthodontic therpy in cses of incisor cross-bite. Eur J Orthod. 1990;12: Vlentine F, Howitt JW. 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