The influence of malocclusion on masticatory performance

Transcription

1 Review Article The influence of on mstictory performnce A systemtic review Isbel Brndão Mglhães ; Lucino José Pereir b ; Lendro Silv Mrques ; Gustvo Huber Gmeiro c ABSTRACT Objective: To systemticlly review the reltionship between s nd mstictory performnce. In ddition, we will perform qulittive nlysis of the methodologicl soundness of the studies. Mterils nd Methods: A literture survey ws done by pplying the Medline dtbse (www. ncbi.nim.nih.gov) in the period from Jnury 1965 to June 2009, using the Medicl Subject Hedings term crossed with vrious combintions of the following terms: mstictory performnce, mstictory efficiency, nd chewing efficiency. The rticles were seprted into two min topics: (1) the influence of tretment (orthognthic surgery) nd (2) the influence of type nd severity. Results: The serch strtegy used identified 78 rticles. After selection ccording to the inclusion/ exclusion criteri, 12 rticles qulified for the finl nlysis. The reserch qulity nd methodologicl soundness were high in one study, medium in 10 studies, nd low in one study. The most serious shortcomings comprised the clinicl trils nd controlled clinicl trils designs with smll smple sizes nd indequte description of selection criteri. Lck of method error nlysis nd the bsence of blinding in mesurements were other exmples of shortcomings. Conclusions: Mls cuse decresed mstictory performnce, especilly s it reltes to reduced occlusl contcts re. The influence of tretment (orthognthic surgery) on mstictory performnce is only mesurble 5 yers fter tretment. (Angle Orthod. 2010;80: ) KEY WORDS: Mstictory performnce; Ml; Orthognthic surgery; Systemtic review INTRODUCTION Deprtment of Clinicl Dentistry, Vle do Rio Verde University UNINCOR, Três Corções-MG, Brzil. b Deprtment of Physiology nd Phrmcology, Federl University of Lvrs UFLA, Lvrs-MG, Brzil. c Deprtment of Physiology, Federl University of Rio Grnde do Sul UFRGS, Porto Alegre-RS, Brzil. Corresponding uthor: Prof Dr Lucino José Pereir, DMV, Physiology nd Phrmcology, Federl University of Lvrs UFLA, Lvrs-MG, Brzil Cix Postl 3037 CEP Lvrs MG, Brzil (e-mil: lucinojosepereir@yhoo.com.br) Accepted: Februry Submitted: Jnury G 2010 by The EH Angle Eduction nd Reserch Foundtion, Inc. Mstiction represents the first stge of the digestive process, during which foods re physiclly broken down into smller prticles to increse their surfce re, thereby fcilitting enzymtic processing during lter stges of digestion. 1,2 Mstiction cn be mesured by severl mens, including mstictory bility, efficiency, nd performnce. Mstictory bility is subjective mesure, perception of how well think they brek down foods. 3 Efficiency pertins to the number of mstictory cycles (ie, number of chews) required to reduce foods to certin size, 4 nd mstictory performnce, the most common nd powerful mesure used, pertins to the prticle size distribution of food chewed fter stndrdized number of cycles. 4,5 Tble 1. Initil Inclusion nd Exclusion Criteri for the Retrieved Studies Inclusion Criteri Exclusion Criteri Studies using objective Cse reports nd cse series prmeters to evlute Review rticles nd bstrcts mstictory performnce Dentl mutilted ptients Studies with untreted/norml Systemic nd neurologic diseses controls Cleft lip nd/or plte or other Articles written in English crniofcil syndrome dignosis DOI: /

2 982 MAGALHÃES, PEREIRA, MARQUES, GAMEIRO Tble 2. Mstictory Performnce Studies in Orthognthic Surgicl Ptients Author Design Groups Zrrinkelk L, CCT I: Ptients before nd et l. 18 fter orthognthic surgery II: Control: skeletl nd dentl Clss I reltionships Vn den et l. 15 Vn den et l. 16 Vn den et l. 17 L, CCT I: Skeletl nd dentl Clss II ptients before nd fter orthognthic surgery L, CCT I: Skeletl nd dentl Clss II ptients before nd fter orthognthic surgery L, CCT I: Skeletl nd dentl Clss II ptients before nd fter orthognthic surgery Smple Size n 5 18 (12 femles, 6 mles) n 5 49 (26 femles, 23 mles) n 5 11 (5 mles, 6 n 5 12 (4 mles, 8 n 5 11 (5 mles, 6 n 5 12 (4 mles, 8 n 5 12 (8 mles, 4 n 5 12 (6 mles, 6 Age, y Methods/ Mesurements (men, 29) Mstictory performnce (medin (men, 26) crrots 20 cycles), swllowing threshold 24.8 (66.4) Mstictory performnce (medin Optosoft 30 cycles), bite force, EMG, chewing cycle durtion Outcome Mesurements: Orthognthic Surgery or Orthopedics Functionl Tretment Ptients produced significntly lrger medin prticle size thn controls both before nd fter surgery. The verge decrese in medin prticle size between preopertive nd postopertive trils for ptients ws not sttisticlly significnt. No significnt difference between ptients nd controls ws detected with regrd to the swllowing threshold. Controls presented better mstictory performnce thn ptients both before nd fter surgery (65.9) The orthognthic surgery did not improve the mstictory performnce in retrognthic ptients, nd no chnge ws found in the bite force, EMG vlues, nd chewing cycle time (66.4) Mstictory performnce (medin Optosoft 15 nd (65.9) cycles), selection nd brekge in one-chew experiment 24.2 (65.1) Mstictory performnce (medin Optosoft 15 cycles), 25.1 (65.9) bite force CCT indictes controlled clinicl trils; L, longitudinl; nd EMG, surfce electromyogrphy. Controls presented better mstictory performnce thn ptients both before nd fter surgery. The orthognthic surgery did not improve the mstictory performnce. Controls hd better selection nd brekge thn ptients, nd these vribles did not improve fter tretment. There ws significnt improvement in mstictory performnce 5 y fter surgery. An increse of the mximum bite force ws not observed. Severl fctors influence mstictory performnce, including body size, bite force, 6 number of functionl tooth units, 7 occlusl contct re, 8 nd s. 9 Although not s potent fctor s the mutilted dentition, s cn negtively ffect bility to process nd brek down foods. 10 Unfortuntely, most of the studies evluting the reltionship between s nd mstiction re not conclusive in terms of identifying the subtle influences of the different types of s on mstictory performnce. Given this bckground, systemtic review ws wrrnted, focusing on the reltionship between s nd mstictory performnce. Furthermore, qulittive nlysis of the methodologicl soundness of the studies in the review ws performed. MATERIALS AND METHODS Serch Strtegies A literture survey ws done by pplying the Medline dtbse ( in the period from Jnury 1965 to June 2009, using the Medicl Subject Hedings term crossed with vrious combintions of the following terms: mstictory performnce, mstictory efficiency, nd chewing efficiency. Selection Criteri The inclusion nd exclusion criteri re given in detil in Tble 1.

3 MALOCCLUSION AND MASTICATORY PERFORMANCE REVIEW 983 Tble 3. Author Design Pncherz CT nd Anehus 22 Mstictory Performnce Studies Regrding Different Ml Types Groups Smple Age, y I: Relpse of overjet fter ctivtor tretment II: Stbility of overjet fter ctivtor tretment Tte CCT I: Preorthognthic et l. 23 surgery ptients Henrikson et l. 24 CCT I: Clss II orthodontic group II: Clss II group (without ny plnned orthodontic tretment) Vn den et l. 25 CCT n 5 9 (1 mle, 8 n 5 10 (3 mles, 7 n 5 35 (23 femles, 12 mles) n 5 58 (31 femles, 27 mles) n 5 65 ( n 5 58 ( III: Norml group n 5 60 ( I: Skeletl nd n 5 12 dentl Clss II (4 mles, ptients before 8 orthognthic surgery Gvião et l. 26 CCT I: Norml II: Posterior cross bite III: Anterior open bite n 5 12 (6 mles, 6 n 5 10 (both genders) n 5 10 (both genders) n 5 10 (both genders) Owens et l. 8 CCT I: Clss I n 5 14 (6 mles, 8 II: Clss II n 5 13 (5 mles, 8 III: Clss III n 5 6 (2 mles, 4 IV: Norml n 5 18 (6 mles, 12 Methods/ Mesurements 28.9 Mstictory performnce (medin Optosil 20 cycles), occlusl contcts, EMG 28.7 ctivity of msseter nd temporl (men, 28.8) (men, 27.2) Mstictory performnce (medin crrots 20 cycles), bite force, EMG ctivity of msseter, nterior nd posterior temporlis 12.8 (61.1) Mstictory performnce (chewing efficiency 12.9 (61.0) index Optosil 20 cycles), mstictory bility (visul nlog scle), occlusl contcts 12.7 (60.7) 24.9 (65.5) Mstictory performnce (medin Optosoft 15 nd 30 cycles), mstictory efficiency (number of 25.1 (65.9) cycles needed to hlve the initil medin prticle size), selection nd brekge in one-chew experiment Mstictory performnce (prticle size re nd perimeter of Optosil 20 cycles) (614.7) Mstictory performnce (medin prticle size nd brodness of prticle distribution of Cuttersil 20 cycles), mstictory bility (swllowing threshold), occlusl contcts Outcome Mesurements: Ml Ptients with relpse of overjet presented poor mstictory performnce, reduced EMG ctivity, nd fewer occlusl contcts in the nterior dentl rch when compred to stble ones. The poor mstictory performnce ws ssocited with fewer intermxillry tooth contcts nd diminished EMG ctivity of the mstictory muscles. Mstictory performnce ws significntly lower in ptients thn in controls. The differences with regrd to bite force nd EMG ctivity were not sttisticlly significnt. The norml group presented better mstictory performnce thn the two Clss II groups, which did not differ between ech other. Few occlusl contcts nd lrge overjet predicted reduced mstictory performnce. Both the mstictory performnce nd efficiency of the ptients were lower thn tht of the controls. Ptients lso hd n impirment of both selection nd brekge of prticles. The norml group presented better mstictory performnce thn did those in the groups with posterior cross bite nd nterior cross bite, which did not differ between ech other. Subjects with norml hd significntly lrger occlusl contcts thn did those with Clss I, Clss II, nd Clss III s, in descending order, but only the difference for brodness of prticles ws sttisticlly significnt with regrd to the mstictory performnce.

4 984 MAGALHÃES, PEREIRA, MARQUES, GAMEIRO Tble 3. Continued Author Design English et l. 10 CCT I: Norml II: Clss I III: Clss II IV: Clss III Toro et l. 27 CCT I: Norml Groups Smple Age, y II: Clss I III: Clss II Methods/ Mesurements n 5 38 n 5 56 n Mstictory performnce (medin prticle size nd brodness of prticle distribution of Cuttersil 20 cycles), mstictory bility (visul nlog scle), swllowing threshold n 5 46 (48% mles, 52% n (86 mles, 53 n (76 mles, 36 n 5 84 (62 mles, Mstictory performnce (medin prticle size nd brodness of prticle distribution of Cuttersil 20 cycles) CCT indictes controlled clinicl trils; CT, clinicl tril; nd EMG, surfce electromyogrphy. Outcome Mesurements: Ml Subjects with norml hd significntly smller prticle sizes nd broder prticle distributions thn with. Ptients with lso perceived chewing disbilities with the hrder foods. The swllowing threshold did not differ between groups. Children with norml hd better mstictory performnce thn those with Clss I. No differences were found between norml nd Clss II. Angle clssifiction nd the Peer Assessment Rtio (PAR) index could not explin most of the vrition in mstictory performnce. Dt Collection nd Anlysis Dt were collected on the following items: uthor, yer of publiction, study design, study groups, methods/mesurements, nd outcome mesurements. The rticles were seprted into two min topics: (1) the influence of tretment (orthognthic surgery) (Tble 2) nd (2) the influence of type nd severity (Tble 3). In ddition, to document the methodologicl soundness of ech rticle, qulity evlution ws performed with respect to preestblished chrcteristics, 11,12 evluting the following eight vribles: (1) study design (rndomized clinicl trils, prospective trils, or controlled clinicl trils [CCTs] 3 points; clinicl trils [CTs] 1 point); (2) dequte smple size 1 point; (3) dequte selection description 1 point; (4) vlid mesurement methods 1 point; (5) Tble 4. Qulity Evlution of the Retrieved Studies Articles Design Smple Size Selection Description Vlid Mesurement Methods Method Error Anlysis Blinding in Mesurement Adequte Sttistics Provided Pncherz nd Anehus 22 CT Indequte Adequte Yes ND ND Yes Tte et l. 23 CCT Indequte Indequte Yes ND ND Yes Zrrinkelk et l. 18 CCT, L Indequte Adequte Yes Yes ND Yes Henrikson et l. 24 CCT Adequte Adequte Yes Yes ND Yes Gvião et l. 26 CCT Indequte Adequte Yes ND ND Yes Vn den et l. 25 CCT Indequte Adequte Yes ND ND Yes Owens et l. 8 CCT Indequte Indequte Yes ND ND Yes English et l. 10 CCT Adequte Adequte Yes ND ND Yes Vn den et l. 15 CCT, L Indequte Adequte Yes ND ND Yes Vn den et l. 16 CCT, L Indequte Adequte Yes ND ND Yes Vn den et l. 17 CCT, L Indequte Adequte Yes ND ND Yes Toro et l. 27 CCT Adequte Adequte Yes ND ND Yes CCT indictes controlled clinicl tril; RCT, rndomized clinicl tril; CT, clinicl tril; L, longitudinl; ND, not declred; EMG, surfce electromyogrphy; nd TMD, temporomndibulr joint dysfunction.

5 MALOCCLUSION AND MASTICATORY PERFORMANCE REVIEW 985 use of method error nlysis 1 point; (6) blinding in mesurement 1 point; (7) dequte sttistics provided 1 point; nd (8) confounders included in nlysis 1 point. Ech study ws ctegorized s low (0 5 points), medium (6 8 points), or high (9 or 10 points). The dt extrction nd qulity scoring from ech rticle were ssessed independently by two reserchers who selected the rticles by reding the title nd bstrcts. All of the rticles tht ppered to meet the inclusion criteri were selected. One hundred percent greement ws obtined in this phse between the two reserchers. The reference lists of the selected rticles were lso serched mnully for dditionl relevnt publictions tht might hve been missed in the dtbse serches. 13 RESULTS The serch strtegy yielded 78 rticles. After selection ccording to the inclusion/exclusion criteri, 12 rticles qulified for the finl nlysis (Tbles 2 nd 3). The reserch qulity nd methodologicl soundness were high in one study, medium in 10 studies, nd low in one study (Tble 4). The most serious shortcomings were the CT nd CCT designs with smll smple sizes nd indequte description of selection criteri. Lck of method error nlysis nd the bsence of blinding in mesurements were other exmples of shortcomings. However, the choice of sttisticl methods ws explined in ll rticles. Considering the use of confounding vribles, only two studies did not report ny fctor. In ll other reports, confounding vribles, such s surfce electromyogrphy, occlusl contcts, bite force, signs nd symptoms of temporomndibulr joint dysfunction, nd nthropometric mesurements, Tble 4. Extended Confounder Fctors Considered EMG nd occlusl contcts EMG nd bite force Skeletl nd dentl reltionship Signs nd symptoms of TMD, occlusl contcts Yes, body weight nd height ND Occlusl contcts re Body weight nd height Bite force nd EMG ND Bite force Anthropometric mesurements Judged Qulity Stndrd: Low (0 5 points), (6 8 points), or High (9 or 10 points) Low High were declred. All mesurement methods used in the studies were vlid. DISCUSSION This systemtic review imed to select ll clinicl trils verifying the reltionship between nd mstictory performnce. No previous review study could be found. Twelve studies were retrieved. From methodologicl point of view, it ws notble tht ll of the studies used exmintion methods without blinding design. In ll studies, the methods used to detect nd nlyze the reltionship between nd mstictory performnce were vlid nd well known. However, gret vritions in test food nd number of cycles were observed, which could mke comprisons mong ll studies difficult. 1,14 On the other hnd, studies published by the sme group were found, llowing more comprehensive conclusions bsed on their results. The influence of tretment (orthognthic surgery) on mstictory performnce showed tht mstiction ws still hmpered in comprison to results obtined from controls, even fter surgicl correction. In ddition, surgicl correction did not improve mstictory performnce significntly. 15,16,18 However, it ws suggested tht fter surgery, some time is needed in order for the muscles to dpt to the new bone position. The muscle fibers re stretched nd my lso decrese bite force when compred to the sitution before surgery. 15,19 This fct ws confirmed when significnt increse in mstictory performnce ws noted 5 yers fter surgery. 17 According to these results, it is importnt to consider tht longitudinl studies with short postsurgicl time evlution should be observed cutiously, since the musculture my need long time to redpt the new incorported modifictions. It seems tht t lest 5 yers re needed to mesure rel improvement in mstictory performnce. 17 In ddition, simultneous evlution of number nd re of occlusl contcts, bite force, muscle thickness, mount of lterl jw movement, pin, nd muscle ctivity re encourged in order to control ll covribles fter orthognthic surgery, once mstictory performnce my be influenced by ll of these fctors. 6,20,21 The influence of type nd severity on mstictory performnce ws lso investigted. In generl, s cused decresed mstictory performnce. 8,10,22 27 Undoubtedly poor mstictory performnce is ssocited with fewer intermxillry tooth contcts. In ddition, diminished muscle ctivity ws noted. 22 A reduced pltform to grind the food ffects

6 986 MAGALHÃES, PEREIRA, MARQUES, GAMEIRO mstictory performnce. 6 Subjects with reduced occlusl contcts re cnnot pulverize their food to the sme extent s with more occlusl units, in fixed number of chewing strokes. Fontijn-Tekmp et l. 28 reported tht the number of occlusl units ws the most importnt fctor tht ffected the medin prticle size of mstictory performnce nd the swllowing threshold. Similr results were previously reported. 7 Occlusl contcts promote mndibulr stbility t mximl intercusption 29 nd hve n influence on chewing function 8 nd mstictory muscle ctivity. 30 Mstictory performnce is lso influenced by bite force. It is believed tht bite force increses with teeth in occlusl contct. 31,32 In ll selected studies, only Tte et l. 23 evluted bite force nd mstictory performnce in orthodontic ptients. The differences with regrd to bite force in preorthognthic surgery ptients nd Clss I ws not sttisticlly significnt. However, in this study, smple size nd selection description were considered indequte for drwing ny further conclusions. Therefore, the correction of through orthodontic tretment becomes n importnt resource with which to improve occlusl contcts nd, consequently, mstictory performnce. CONCLUSIONS N Mls cuse decresed mstictory performnce, especilly s it reltes to reduced occlusl contcts re. N The influence of tretment (orthognthic surgery) on mstictory performnce is only mesurble 5 yers fter tretment. ACKNOWLEDGMENT The uthors re grteful to the Brzilin fostering gencies: Fundção de Ampro Pesquis do Estdo de Mins Geris (FAPEMIG) nd Fundção de Ampro Pesquis do Estdo do Rio Grnde do Sul (FAPERGS), which supported the present study. REFERENCES 1. Pereir LJ, Gvião MBD, vn der Bilt A. Influence of orl chrcteristics nd food products on mstictory function. Act Odontol Scnd. 2006;64: vn der Bilt A, Engelen L, Abbink J, Pereir LJ. Effects of dding fluids to solid foods on muscle ctivity nd number of chewing cycles. Eur J Orl Sci. 2007;115: Crlsson GE. Mstictory efficiency: the effect of ge, the loss of teeth nd prosthetic rehbilittion. J Int Dent. 1984; 34: Btes JF, Stfford GD, Hrrison A. Mstictory function review of the literture. J Orl Rehb. 1976;3: Slgter AP, Bosmn F, vn der Gls HW, vn der Bilt A. Humn jw elevtor muscle ctivity nd food comminution in the dentte nd edentulous stte. Arch Orl Biol. 1993;38: Fontijn-Tekmp FA, Slgter AP, vn der Bilt A, et l. Biting nd chewing in overdentures, full dentures, nd nturl dentitions. J Dent Res. 2000;79: Htch JP, Shinki RS, Ski S, Rugh JD, Punovich ED. Determinnts of mstictory performnce in dentte dults. Arch Orl Biol. 2001;46: Owens S, Buschng PH, Throckmorton GS, Plmer L, English J. Mstictory performnce nd res of occlusl contct nd ner contct in with norml nd. Am J Orthod Dentofcil Orthop. 2002; 12: Buschng Peter H. Mstictory bility nd performnce: the effects of mutilted nd mloccluded dentitions. Semin Orthod. 2006;12: English JD, Buschng PH, Throckmorton GS. Does ffect mstictory performnce? Angle Orthod. 2002;72: Antczk AA, Tng J, Chlmers TC. Qulity ssessment of rndomized control trils in dentl reserch I. Methods. J Periodont Res. 1986;21(4): Jdd AR, Moore RA, Crroll D, Jenkinson C, Reynolds DJ, Gvghn DJ, McQuy HJ. Assessing the qulity of reports of rndomized clinicl trils: is blinding necessry? Control Clin Trils. 1996;17: Andrde AS, Gmeiro GH, Derossi M, Gvião MBD. Posterior crossbite nd functionl chnges systemtic review. Angle Orthod. 2009;79: Gmbreli FR, Serr MD, Pereir LJ, Gvião MBD. Influence of mesurement technique, test food, teeth nd muscle force interctions in mstictory performnce. J Texture Stud. 2007;38: vn den W, vn der Gls H, vn der Bilt A, Bosmn F. Mstictory function in retrognthic ptients, before nd fter mndibulr dvncement surgery. J Orl Mxillofc Surg. 2004;62: vn den W, vn der Bilt A, vn der Gls HW, Bosmn F, Rosenberg A, Koole R. The influence of orthognthic surgery on mstictory performnce in retrognthic ptients. J Orl Rehbil. 2005;32: vn den W, vn der Bilt A, vn der Gls H, Rosenberg T, Koole R. The influence of mndibulr dvncement surgery on orl function in retrognthic ptients: 5-yer follow-up study. J Orl Mxillofc Surg. 2006;64: Zrrinkelk HM, Throckmorton GS, Ellis E III, Sinn DP. A longitudinl study of chnges in mstictory performnce of ptients undergoing orthognthic surgery. J Orl Mxillofc Surg. 1995;53: ; discussion, Finn RA, Throckmorton GS, Bell WH, et l. Biomechnicl considertions in the surgicl correction of mndibulr deficiency. Orl Surg. 1980;38: vn der Bilt A, Engelen L, Pereir LJ, vn der Gls HW, Abbink JH. Orl physiology nd mstiction. Physiol Behv. 2006;89: Cstelo PM, Gvião MBD, Perreir LF, Bonjrdim LR. Mstictory muscle thickness, bite force, nd occlusl contcts in young children with unilterl posterior crossbite. Eur J Orthod. 2007;29: Pncherz H, Anehus M. Mstictory function fter ctivtor tretment. An nlysis of mstictory efficiency, occlusl contct conditions nd EMG ctivity. Act Odontol Scnd. 1978;36: Tte GS, Throckmorton GS, Ellis E III, Sinn DP. Mstictory performnce, muscle ctivity, nd occlusl force in pre orthognthic surgery ptients. J Orl Mxillofc Surg. 1994; 52: ; discussion, 482.

7 MALOCCLUSION AND MASTICATORY PERFORMANCE REVIEW Henrikson T, Ekberg EC, Nilner M. Mstictory efficiency nd bility in reltion to nd mndibulr dysfunction in girls. Int J Prosthodont. 1998;11: vn den W, vn der Gls HW, vn der Bilt A, Bosmn F. Chewing efficiency of pre-orthognthic surgery ptients: selection nd brekge of food prticles. Eur J Orl Sci. 2001;109: Gvião MB, Rymundo VG, Sobrinho LC. Mstictory efficiency in children with primry dentition. Peditr Dent. 2001;23: Toro A, Buschng PH, Throckmorton G, Roldán S. Mstictory performnce in children nd dolescents with Clss I nd II s. Eur J Orthod. 2006;28: Fontijn-Tekmp FA, vn der Bilt A, Abbink JH, Bosmn F. Swllowing threshold nd mstictory performnce in dentte dults. Physiol Behv. 2004;432: Rodrigues CH, Mori M, Rodrigues AA, Nscimento EJ, Gonçlves FM, Sntn KC. Distribution of different types of occlusl contcts t mximl intercuspl position in deciduous dentition. J Clin Peditr Dent. 2003;27: Ferrrio V, Serro G, Dellvi C, Cruso E, Sforz C. Reltionship between the number of occlusl contcts nd mstictory muscle ctivity in helthy young dults. J Crniomndibulr Prct. 2002;20: Sonnesen L, Bkke M, Solow B. Bite force in preorthodontic children with unilterl crossbite. Eur J Orthod. 2001;23: Sonnesen L, Bkke M. Molr bite force in reltion to, crniofcil dimensions, nd hed posture in pre-orthodontic children. Eur J Orthod. 2005;27:58 63.