Review Article Long-term Skeletl Chnges with Rpid Mxillry Expnsion: A Systemtic Review Mnuel O. Lgrvere ; Pul W. Mjor b ; Crlos Flores-Mir c Abstrct: The objective ws to evlute long-term trnsverse, nteroposterior nd verticl skeletl chnges fter rpid mxillry expnsion (RME). The dt were clinicl trils tht ssessed skeletl chnges through cephlometric nlysis. No surgicl or other simultneous tretment during the evlution period ws ccepted. Electronic dtbses (PubMed, Medline, Medline In- Process & Other Non-Indexed Cittions, Cochrne Dtbse of Systemtic Reviews, ASP Journl Club, DARE, CCTR, Embse, Web of Sciences nd Lilcs) were serched with the help of senior Helth Sciences librrin. Abstrcts tht ppered to fulfill the initil selection criteri were selected by consensus. The originl rticles were then retrieved. A methodologicl checklist ws used to evlute the qulity of the selected rticles. Their references were lso hnd-serched for possible missing rticles. Articles without n dequte control group to fctor out growth chnges were excluded. Only three rticles (one mesuring trnsverse nd two nteroposterior nd verticl chnges) mesured RME stbility fter ctive expnsion, ll of them hd some methodologicl flws, which limit the ttinble conclusions. An individul nlysis of these rticles ws mde. Long-term trnsverse skeletl mxillry increse is pproximtely 25% of the totl dentl expnsion for prepubertl dolescents. Better long-term outcomes re expected in trnsverse chnges becuse of RME in less skeletlly mture ptients. RME ppers not to produce cliniclly significnt nteroposterior or verticl chnges in the position of the mxill nd mndible. The conclusions from this systemtic review should be considered with cution becuse only secondry level of evidence ws found. Long-term rndomized clinicl trils re needed. (Angle Orthod 2005;75:1046 1052.) Key Words: Rpid mxillry expnsion; Skeletl chnges; Rpid pltl expnsion INTRODUCTION When skeletl constricted mxillry rch is dignosed, orthopedic skeletl expnsion involving sep PhD Student, Orthodontic Grdute Progrm, Fculty of Medicine nd Dentistry, University of Albert, Edmonton, Cnd. b Professor, Director of the Orthodontic Grdute Progrm, Fculty of Medicine nd Dentistry, University of Albert, Edmonton, Cnd. c Postdoctorl Fellow, Orthodontic Grdute Progrm, Fculty of Medicine nd Dentistry, University of Albert, Edmonton, Cnd. Corresponding uthor: Crlos Flores-Mir, DDS, MSc, Cert Orth, PhD, Fculty of Medicine nd Dentistry, Room 4051A, Dentistry/Phrmcy Centre, University of Albert, Edmonton, Albert, Cnd T6G 2N8 (e-mil: crlosflores@ulbert.c) Accepted: September 2004. Submitted: June 2004. 2005 by The EH Angle Eduction nd Reserch Foundtion, Inc. rtion of the midpltl suture is the tretment of choice. Three tretment lterntives re vilble for this purpose: rpid mxillry expnsion (RME), slow mxillry expnsion (SME), nd surgicl-ssisted RME (SARME). Both SME nd RME re indicted for growing ptients, wheres SARME is the lterntive selected for nongrowing dolescent nd young dult ptients. Even though RME tretments were reported to bring cliniclly stble results, 1 others reported relpse fter expnsion ws ttined. 2 Yers lter, other studies demonstrted tht the ttined chnges were produced primrily in the underlying structures nd, therefore, stble results were expected. 3,4 Although, SME nd RME were reported to bring similr results, 5 theoreticlly RME delivers forces rnging from 15 to 50 N wheres the SME incorportes forces tht only rech 10 N of mgnitude. Becuse RME tretments exert greter force on prmxillry 1046
LONG-TERM SKELETAL CHANGES WITH RME structures, chnges in skeletl structures other thn in the mxill re more fesible. Some disdvntges hve been reported in RME including: bite opening, 6 relpse, 7,8 microtrum of the TMJ nd the midpltl suture, 7,8 nd root resorption. 7,8 Becuse direct reltionship hs been reported between incresed resistnce to skeletl expnsion nd incresed ptient ge, the use of SME in dolescents my be questioned becuse it my not offer enough expnsion force to seprte the midpltl suture in young dults. 9 Even in young children, no scientific evidence in fvor or ginst is vilble. 10 Severl disdvntges for SME re minor mxillry nd mndibulr plne chnges, 11 poor fit, frcture or loss of the pplince, 12 nd pltl irrittion. 12 SARME tretment hs been successful in splitting the pltine suture nd thus widening the mxill in young dults. 13 However, this surgicl procedure is costly nd requires outptient surgery or hospitliztion with ttendnt morbidity nd loss of work time. Other complictions reported with the SARME re tissue irrittion, hemorrhge, infection, pin, unilterl or symmetric expnsion, periodontl problems, nd relpse. 14 For these resons, creful cost-effectiveness nlysis should be mde by ptients nd orthodontists before undergoing the procedure. 13 From this literture review, RME ppers s the tretment of choice in growing dolescents. Previous reports on RME skeletl nd dentl effects re contrdictory becuse of vrible study designs, smple sizes, nd reserch pproches. 15,16 Two met-nlyses regrding the trnsverse dentl effects of RME hve been published. 15,17 One systemtic review 18 bout the long-term dentl effects of RME hs been published, but to dte there re no systemtic reviews regrding long-term skeletl effects. The purpose of this systemtic review is to evlute long-term (minimum of one-yer postctive tretment) trnsverse, nteroposterior, nd verticl skeletl chnges obtined fter RME. MATERIALS AND METHODS The following inclusion criteri were chosen to initilly select the pproprite rticles from the published bstrcts: humn clinicl trils; mesurements mde from fcil rdiogrphs (nteroposterior nd lterl cephlogrms); no surgicl or other simultneous tretment tht could ffect RME effect during the evlution period. A computerized serch ws then conducted using Medline (from 1966 to week 1 of September 2004), Medline In-Process & Other Non-Indexed Cittions (from week 1 of September 2004 to week 2 of September 2004), Lilcs (from 1982 to September 2004), 1047 PubMed (1966 to week 2 of September 2004), Embse (from 1988 to week 37 of 2004), web of science (1945 to week 2 of September 2004) nd ll EBM reviews (Cochrne Dtbse of Systemtic Reviews, ASP Journl Club, DARE nd CCTR) (to the third qurter of 2004) dtbses for skeletl chnges in RME. Terms used in this literture serch were rpid pltl expnsion or RME, bone nd bones or skeletl chnges. The selection of these terms were mde with the help of senior librrin specilized in Helth Sciences dtbses. No ttempts were mde t this stge to identify studies tht did not use dequte control groups to fctor out growth chnges. It ws considered improbble tht the bstrcts would necessrily report enough informtion regrding control groups, which would potentilly exclude some rticles. Eligibility of potentil studies ws determined by reding the title nd bstrcts of ech rticle identified by ech serch engine. Two reserchers selected the rticles to be collected on the bsis of the bstrct informtion. An interexminer greement of 0.900 (interexminer Kpp) ws obtined. Any discrepncies were settled through discussion. All the rticles tht ppered to meet the inclusion criteri on the bsis of their bstrcts were selected nd collected. In ddition, the ctul rticles were lso obtined from bstrcts in which not enough relevnt informtion ws stted. The finl selection ws independently completed by three reserchers reding the complete rticles nd their results were compred. An interexminer greement of 0.885 (interexminer Kpp) ws obtined. Use of n dequte control group to fctor out growth chnges ws considered necessry t this stge. Any discrepncies were settled through discussion. Reference lists of the selected rticles were hndserched for dditionl relevnt publictions tht my hve been missed in the dtbse serches. In cses where specific dt ws necessry for the discussion, nd ws not specified in the rticle, efforts were mde to contct the uthors to obtin the required extr informtion. RESULTS The serch results nd the finl number of bstrcts selected ccording to the initil selection criteri from the vrious dtbses re provided in Tble 1. Compring the dtbse results, Medline obtined the gretest diversity of finlly selected bstrcts (78.6%), wheres the other dtbses obtined significntly fewer finlly selected bstrcts ( 33.3%). The different dtbses repeted most of the bstrcts, except Lilcs, which included only Ltin-Americn public-
1048 LAGRAVERE, MAJOR, FLORES-MIR TABLE 1. PubMed Medline Serch Results from Different Dtbses Dtbse Keywords Results Selected Medline In-Process & Other Non-Indexed Cittions Embse All EBM reviews (Cochrne Dtbse of Systemtic Reviews, ASP Journl Club, DARE nd CCTR) Web of Science Lilcs (1) Rpid mxillry expnsion nd skeletl chnges; (2) rpid pltl expnsion nd skeletl chnges; (3) #1 OR #2 expn$.mp; (2) limit to humn; (3) skeletl chnges.mp; (4) 1 nd 2 nd 3 expn$.mp; (2) limit to humn; (3) skeletl chnges.mp; (4) 1 nd 2 nd 3 expn$.mp; (2) limit to humn; (3) skeletl chnges.mp; (4) 1 nd 2 nd 3 expn$.mp; (2) limit to humn; (3) skeletl chnges.mp; (4) 1 nd 2 nd 3 (1) TS (rpid mxillry expnsion); (2) TS (rpid pltl expnsion); (3) TS (skeletl chnges); (4) #1 OR #2; (5) #3 AND #4 DocType Article; Lnguge All lnguges; Dtbse(s) SCI- EXPANDED, SSCI, A&HCI (1) Rpid mxillry expnsion; (2) Rpid pltl expnsion; (3) #1 OR #2 Percentges do not dd up to 100% s the sme reference could be found in severl dtbses. Percentge of Totl Selected Abstrcts (42) 27 14 33.3 159 33 78.6 0 0 0 33 2 4.8 21 4 9.6 9 2 4.8 33 9 21.4 TABLE 2. Studies tht Fulfilled Initil Selection Criteri but Were Lter Rejected Authors Bhtt nd Jcob 19 Linder-Aronson nd Lindgren 20 d Silv et l 21 d Silv et l 22 Velzquez et l 23 Asnz et l 24 Sndikcioglu nd Hzr 9 Akky et l 6 Memikoglu nd Iseri 25 Ursi et l 26 Brmnte nd Almeid 27 Frnchi et l 28 Cozz et l 29 Cross et l 30 Reson(s) for Rejection No control group nd no error of method No control group, no error of method nd pplince design No control group, no error of method nd no retention period No control group, no error of method nd no retention period No control group No control group nd no error of method No control group No control group nd no retention period No control group No control group nd no error of method No control group, no error of method nd pplince design Dtbse repetition Only short-term chnges Only short-term chnges Error of method, mgnitude of the mesurement error; retention period, specified retention period nd type; pplince design, pplince modified significntly compred to RME trditionl design; dtbse repetition, sme dt used in different study; short-term chnges, only immedite chnges (fter expnsion phse) were reported. tions nd ccounted for significnt percentge (21.4%) of the finlly selected bstrcts. From the 42 studies tht on the bsis of the bstrcts seemed to be potentilly useful, only 17 studies ctully fulfilled the initil selection criteri fter reding the complete rticle. Mnul serching of the references from these 42 studies did not revel ny study tht hd not ppered in the electronic serch. At the finl stge of rticle selection, eleven 5,12,19 27 of the 17 rticles were rejected becuse of the lck of n dequte control group, one 28 becuse it used the sme dtbse s nother selected study nd two 29,30 becuse they only evluted short-term (six nd three months fter insertion of pplince, respectively) skeletl chnges. Lck of reported mesurement error 19 22,24,26,27 or use of unconventionl cephlometric nlysis 28 were lso found in some studies (Tble 2). Finlly, only three rticles tht met ll the inclusion criteri remined. A summry of the smple size, retention period, rdiogrphs, nd pplince used is given in Tble 3. A methodologicl qulity checklist ws developed to evlute the selected rticles (Tble 4),
LONG-TERM SKELETAL CHANGES WITH RME 1049 TABLE 3. Studies Finlly Included Authors Smple Control Method Error Reported Rdiogrphs Chng et l 6 18 femle nd seven mle (11.8 yers) seven femle nd 16 mle (11.8 yers) Yes Lt Cephs Bccetti et l 31 25 femles nd 17 mles (grouped ccording nine femles nd 11 mles (grouped c- Yes PA Cephs to skeletl ge) cording to skeletl ge) Grib et l 32 11 mles nd 14 femles (13.6 yers; 11 17.4 yers) 13 mles nd 13 femles (pired ccording to ge with tretment group) Yes Lt Cephs TABLE 4. Methodologicl Score for the Clinicl Trils I. Study Design (9 ) A. Objective: objective clerly formulted ( ) B. Popultion: described ( ) C. Selection criteri: clerly described ( ); dequte ( ) D. Smple size: considered dequte ( ); estimted before collection of dt ( ) E. Bseline chrcteristics: similr bseline chrcteristics ( ) F. Timing: prospective ( ) G. Rndomiztion: stted ( ) II. Study Mesurements (5 ) H. Mesurement method: pproprite to the objective ( ) I. Blind mesurement: blinding (exminer, sttisticin ) J. Relibility: described ( ), dequte level of greement ( ) III. Sttisticl Anlysis (6 ) K. Dropouts: dropouts included in dt nlysis ( ) L. Sttisticl nlysis: pproprite for dt ( ); combined subgroup nlysis ( ) M. Confounders: confounders included in nlysis ( ) N. Sttisticl significnce level: P vlue stted ( ); confidence intervls ( ) Mximum number of s 20. nd the ppliction of the methodologicl qulity checklist is provided in Tble 5. A flow digrm of the literture serch ppers in Tble 6. From the three finl rticles, one mesured trnsverse chnges, two nteroposterior chnges, nd two verticl chnges. All the three rticles mesured long-term RME stbility (more thn five yers fter finishing full ctive tretment). Trnsverse chnges The only sttisticlly significnt difference in skeletl width increse for ptients before nd fter pek pubertl growth spurt ws lteronsl width ( 1.5 mm). For the erly-treted group, the mxillry width increse ws significnt (three mm) but not for the ltetreted group (0.9 mm). The uthors concluded tht ptients treted before compred with fter pubertl pek exhibit cliniclly significnt nd more effective long-term chnges t the skeletl level in both mxillry nd circummxillry structures. 31 Anteroposterior chnges There ws no significnt difference except for the position of A point, which ws more retruded in the RME-treted group ( 1.05 when compred with control group). No significnt chnges were lso found for the nteroposterior position of the mxill nd mndible. 6 When compred with the control group, they found tht the mxill nd mndible presented similr chnges in both groups. No sttisticlly significnt chnges were found concerning the nteroposterior position of the mxill nd mndible. 32 Verticl chnges Any sttisticlly significnt short-term differences were found in skeletl verticl cephlometric vribles. The mndibulr plne ngle reduction between pretretment nd long-term follow-up ( 0.85 ) ws less for the RME thn the two comprison groups ( 2.52 in group treted with full fixed pplinces nd 2.21 for control group). 6 A sttisticlly significnt long-term difference ws present in the SN-PP (0.8 ) nd SN-Gn (0.8 ) ngles when compring the tretment group with the control TABLE 5. Methodologicl Score of Selected Articles Articles A B C D E F G H I J K L M N Totl no. of Checks Percentge of The Totl Chng et l 6 9.5 45.00 Grib et l 32 9.5 45.00 Bccetti et l 31 12 60 A M: methodologicl criteri in Appendix 1;, fulfilled stisfctorily the methodologicl criteri (1 check point);, fulfilled prtilly the methodologicl criteri (0.5 check point);, did not fulfill the methodologicl criteri (0 check point).
1050 LAGRAVERE, MAJOR, FLORES-MIR TABLE 6. Flow Digrm of the Literture Serch Electronic serch 188 bstrcts Selection criteri on 188 bstrcts excluded 146 Selection criteri on 42 ppers Mnul serch 0 ppers excluded 25 Potentilly pproprited to be included 0 ppers Potentilly pproprited to be included 17 ppers 17 ppers excluded 11 lck of control group 6 ppers excluded 1 repetition of smple 5 ppers finlly selected group. No significnt chnge ws found for the verticl mesurements between the end of ctive tretment nd the follow-up. 32 DISCUSSION Much informtion bout RME hs been published, but the conclusions hve been contrdictory. Two met-nlyses 15,17 nd one systemtic review 16 nlyzed only RME dentl chnges. These met-nlyses nd systemtic review concluded tht tril results for dentl chnges were inconclusive nd recommendtions for clinicl prctice could not be supported. However, one previous systemtic review 18 found tht long-term trnsversl chnges were cliniclly significnt. No previous systemtic review or met-nlysis hs been published regrding the long-term skeletl effects of RME. Even though there re considerble number of studies deling with skeletl chnges with RME procedures, the mjority of reports bout RME skeletl chnges were excluded becuse of the bsence of control group to fctor out the norml growth chnges tht could hve hppened during the expnsion nd retention periods. Also, some of them did not provide the error of methods. Knowledge of the mesurement error is essentil in judging the clinicl significnce of ny reported sttisticlly significnt findings. Finlly, methodologicl fctors such s different postctive tretment evlution periods nd differences in the lndmrks evluted between the two studies tht met the inclusion criteri nd evluted skeletl nteroposterior nd verticl chnges prevented use of met-nlysis. The individul significnt differences found were sttisticlly significnt not cliniclly significnt, nd therefore, met-nlysis would not hve dded significntly to our knowledge bout long-term skeletl chnges fter RME. Although three studies stisfied the finl inclusion criteri for this systemtic review, conclusions should be mde nd evluted with cution. The finlly selected studies presented methodologicl issues such s lck of description of sttisticl estimtion process for the smple size, dropouts, nd intr- nd interexminer relibility. Although ssessing study qulity is subjective nd dependent on dequte reporting in the journl rticles, 33 it gives comprtive ide of the methodologicl qulity of the studies. Within the limittions of the qulity score list used, scores for the finlly selected studies were limited. Long-term rndomized clinicl trils re required to obtin sound clinicl conclusions bout the effectiveness of RME t the skeletl level. Also, these studies filed to give the higher level of scientific evidence, which is only ttinble through the use of rndomized clinicl trils. 34 In the bsence of the highest level of evidence, clinicins hve to mke decisions bsed on lower levels of evidence. Nonrndomized controlled trils, such s the ones found, represent only the second level of evidence nd re prone to confounding nd selection bis. 35 Therefore, creful nlysis of their results tht considers their limittions is required. Differences were found for the trnsverse mxillry skeletl chnges ccording to the mturtion stge of the subjects. For the lteronsl width ( 1.5 mm), the expnsion effects were significnt for both groups. On the other hnd, the mxillry width increse ws only significnt (three mm) for the erly-treted group but not for the lte-treted group. The uthors concluded tht ptients treted before pubertl pek growth exhibit cliniclly significnt nd more effective long-term chnges t the skeletl level in both mxillry nd circummxillry structures. 31 Therefore, mxillry skeletl width increse ppers to be pproximtely 20% of the totl pplince ctivtion in prepubertl dolescents but not significnt for postpubertl dolescents.
LONG-TERM SKELETAL CHANGES WITH RME Concerning nteroposterior chnges in the mxill nd mndible, no significnt ltertions were found in ny of the studies reviewed. 6,32 After the posttretment nd postretention, the mxill nd mndible of the treted groups presented similr behvior to the ones of the control group, ie, the differences presented no sttisticl or clinicl significnce. Short-term nd long-term verticl skeletl chnges ssocited with RME pper to be restricted to the mxill. The mgnitude of chnge reported by Grib et l 32 ws smll nd, in view of the rnge of mesurement error, hs little, if ny, clinicl significnce. The long-term chnges in mndibulr plne ngle reported by Chng et l 6 re lso of little, if ny, clinicl significnce. Scientific evidence lone does not utomticlly dictte the selection of the tretment. A combintion of vlues from the ptient nd professionl (clinicl, personl, nd socil) should determine whether the intervention benefits re worth the costs. 36 Therefore, the ppliction of evidence into clinicl prctice hs to be relted to professionl expertise nd ptient vlue needs. As in ny usul clinicl environment, clinicins will need to rely on their clinicl experience, the opinion of experts, nd the presented limited evidence concerning RME skeletl short- nd long-term results. CONCLUSIONS The following conclusions for this systemtic review should be considered with cution becuse only secondry level of evidence ws found. Long-term prospective rndomized clinicl trils re needed to support these findings: Long-term stbility of trnsverse skeletl mxillry increse is better in skeletlly less mture individuls (prepubertl growth pek) thn skeletlly more mture (pubertl nd postpubertl growth pek) individuls. The clinicl significnce of long-term mxillry expnsion in skeletlly more mture groups is questionble. Long-term trnsverse skeletl mxillry increse is pproximtely 25% of the totl pplince djustment (dentl expnsion) in prepubertl dolescents but not significnt for postpubertl dolescents. RME did not produce significnt nteroposterior or verticl chnges in the position of the mxill nd mndible. ACKNOWLEDGMENT Specil thnks to Lind Sele for her professionl ssistnce in the dtbse serch. REFERENCES 1051 1. Hs AJ. Pltl expnsion: just the beginning of dentofcil orthopedics. Am J Orthod. 1970;57:219 255. 2. Timms DJ. An occlusl nlysis of lterl mxillry expnsion with midpltl suture opening. Dent Prct Dent Rec. 1968;18:435 441. 3. Hs AJ. Long-term posttretment evlution of rpid pltl expnsion. Angle Orthod. 1980;50:189 217. 4. Pvlin D, Vukicevic D. Mechnicl rections of fcil skeleton to mxillry expnsion determined by lser hologrphy. Am J Orthod. 1984;85:498 507. 5. Akky S, Lorenzon S, Ucem TT. 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