Occlusal Status in Asian Male Adults:

Transcription

1 Originl Article Occlusl Sttus in Asin Mle Adults: Prevlence nd Ethnic Vrition Jen Soh ; Andrew Sndhm ; Yiong Huk Chn c Astrct: The purpose of this study ws to determine the occlusl sttus in young Asin mle dults of three ethnic groups. Study models of smple of mle rmy recruits (N 33, ge yers) with no history of orthodontic tretment were ssessed. The ethnic proportions of the smple were 76.1, Mly 17.7 (n 6), nd Indin 6.2. British Stndrd Institute (BSI) nd Angle s clssifiction were used to determine incisor nd molr reltionships, respectively. Chi-squre test or Fisher s Exct test ws performed to compre the occlusl trits etween ethnic groups. The distriution of incisor reltionships of the totl smple consisted of Clss I 48.1, Clss II/1 26.3, Clss II/2 3.2, nd Clss III Right Angle s molr reltionships were 4., 24.5, nd 24.2 wheres left Angle s molr reltionships were 53.1, 25.1, nd 21.2 for Clss I, II, nd III, respectively. Comprison etween ethnic groups found tht Indin sujects were more likely to hve Clss II/1 mlocclusions nd cliniclly missing permnent teeth (P.5). The study found tht the overll prevlence of mlocclusion (BSI) ws Clss I, Clss II/1, Clss III, nd Clss II/2 in descending order of proportions. Angle s Clss I molr ws most prevlent followed y Clss II nd Clss III reltions. A significnt difference in occlusl sttus etween the ethnic groups ws found regrding incisor reltionship nd missing permnent teeth (P.5). (Angle Orthod 25;75: ) Key Words: BSI incisor clssifiction; Angle s molr clssifiction; ; Mly; Indin INTRODUCTION Mlocclusion hs een defined s devition from norml occlusion. Good documenttion of occlusl sttus is vlule from n epidemiologicl stndpoint ecuse it descries the rnge of occlusl vritions within the community in which orthodontic tretment my e instituted. Prevlence studies on mlocclusion hve lso een closely ssocited with the ssessment of orthodontic tretment need in vrious communities. 1 5 Informtion from such studies provided the Assistnt Professor, Deprtment of Preventive Dentistry, Ntionl University of Singpore, Singpore, Singpore. Professor, Orthodontic Deprtment, Fculty of Medicine, Acdemic Hospitl, University of Groningen, Groningen, The Netherlnds. c Hed of Biosttistics, Clinicl Trils nd Epidemiology Reserch Unit, Singpore, Singpore. Corresponding uthor: Jen Soh, BDS, MDS, MOrthEd, FAMS, Deprtment of Preventive Dentistry, Fculty of Dentistry, Ntionl University Hospitl Min Building, Ntionl University of Singpore, 5 Lower Kent Ridge Rod, Singpore, Singpore (e-mil: pndsj@nus.edu.sg) Accepted: My 24. Sumitted: Ferury y The EH Angle Eduction nd Reserch Foundtion, Inc. sic informtion for the plnning nd progress of orthodontic delivery service to the pulic s well s the trining of orthodontic specilists to meet the orthodontic need nd demnd. The methods of recording occlusl trits cn e rodly divided into qulittive nd quntittive mesurements. 6 Qulittive methods commonly used include British Stndrd Institute (BSI) of incisor clssifiction 7 nd Angle s clssifiction for molr reltionship. 8 These methods re useful in descriing the occlusl trits for mens of ctegorizing vrious types of dentl mlocclusions for quick nd esy documenttion s well s providing common chnnel of communiction mong dentl professionls. Literture shows tht these methods hve een used extensively in numerous mlocclusion prevlent studies. Quntittive methods such s overjet nd overite mesurements in millimeters hd lso een used in popultion studies. 11 These methods re useful in descriing the extent of devition of n occlusl trit in numericl formt s n independent descriptor or s component in the scoring of mlocclusion for the purpose of estlishing the severity of mlocclusion nd tretment prioritiztion A study on smple of 38 Swedish men etween 814

2 OCCLUSAL STATUS IN ASIAN MALE ADULTS the ges of 21 nd 54 yers found tht 75 hd mlocclusions nd 45 hd dentl crowding with dentl rottions eing the most common occlusl trit. 15 Another Swedish study on Cucsins found tht distriution of mlocclusions for the totl smple ws 71, 23, nd 5 for Angle s Clss I, II, nd III, respectively. Spcing nd unilterl crossite were found to e more prevlent in mles thn femles. 16 A Dutch study found tht 78 of the mles hd overjet etween zero nd four mm, nd 21 of the mles hd overjet greter thn five mm. The prevlence of mlocclusion for the totl smple ws 6, 28, nd 2 for Angle s Clss I, II, nd III, respectively. 17 Clss III mlocclusions were more commonly ssocited with mle dult orthodontic ptients. 18 The molr reltionships found in Hong Kong mle dults were 64.8 Clss I, 15.7 Clss II, nd 1.4 Clss III. The overjet mesurements showed tht 71.3 hd Clss I incisors, 13 Clss II, nd 15.8 Clss III. 1 The occlusl distriution found in Austrlin Cucsin dults ws 67.1 Clss I, 28.7 Clss II, nd 4.2 Clss III. 2 A recent lrge-scle survey on mlocclusion sttus in the United Sttes found tht only 35 of dults hd well-ligned mndiulr incisors nd 15 hd severe incisor irregulrity tht ws potentilly hndicpping in terms of socil cceptility nd occlusl function. The survey lso detected n ethnic difference in the prevlence of incisor irregulrity nd severity of Clss II nd III mlocclusions etween Mexicn-Americns nd the rest of the popultion. The ims of this study were to (1) descrie the occlusl sttus in Asin mle dults nd (2) compre the ethnic vrition in occlusl sttus. MATERIALS AND METHODS A smple of mle rmy recruits (N 33, ge yers) with no previous history of orthodontic tretment prticipted in this reserch on voluntry sis with informed consent. Sujects with crniofcil nomlies (eg, cleft lip or plte, or oth) were excluded. Dt collection ws crried out once week for period of 11 weeks t the only preenlistment recruitment center tht performed medicl nd dentl exmintions. The first 3 consecutive sujects of the dy who volunteered hd lginte impressions tken, with the susequent study csts used to ssess the occlusl trits. Sujects with missing permnent teeth were interviewed for their history of dentl extrctions. The incisor reltionship ws clssified ccording to the British Stndrd Institute (183) 7 s descried elow: Clss I the lower incisl edges occlude with or lie immeditely elow the cingulum plteu of the upper incisors. 815 Clss II the lower incisor edges lie posterior to the cingulum plteu of the upper centrl incisors. Division 1 the overjet is incresed, nd the upper centrl incisors re proclined. Division 2 the overjet is miniml or incresed with retroclined upper centrl incisors. Clss III the lower incisor edges ly nterior to the cingulum plteu of the upper centrl incisors. The overjet is reduced or reversed. Overjet nd overite mesurements were lso mde using metl ruler (ccurte up to.5 mm) nd dopting the method proposed y Brunelle et l. 1 Recording of the other occlusl trits were s follows: Crossite nterior crossite ws recorded when one or more upper incisor teeth were pltl to the lower incisor teeth t mximum intercusption. Buccl crossite ws recorded when one or more lower posterior teeth in ny qudrnt distl to the lterl incisor were plced uccl to the upper posterior teeth t mximum intercusption. Lingul crossite/ scissors ite ws recorded when one or more lower posterior teeth in ny qudrnt distl to the lterl incisor were lingully plced with respect to the upper posterior teeth t mximum intercusption. Molr reltionship right nd left molr reltionships were clssified sed on Angle s clssifiction. Missing teeth nd retined deciduous teeth missing tooth or teeth except cliniclly sent third molrs were recorded. Dentitions with retined primry molrs were ssumed to hve missing permnent successors. Retined deciduous tooth or teeth were recorded. Incisor crowding liner contct point displcement etween djcent incisors of the mxillry nd mndiulr rches were mesured using ruler nd summted to give totl score. The scores were ctegorized into idel (zero mm), mild (1 3 mm), moderte (4 6 mm), nd severe ( 7 mm) crowding. Sttisticl nlysis All sttisticl nlyses were performed using SPSS 11.. Descriptive sttistics for the distriution of occlusl trits of the totl smple nd etween ethnic groups ws presented using frequencies, percentges, nd 5 confidence intervl (CI). A goodness-offit test on the ethnic distriution of the smple with the popultion census 21 ws performed. The ssocition etween occlusl trits nd ethnic groups ws ssessed using Chi-squre or Fisher s Exct test with odds rtios presented where pplicle. Sttisticl significnce ws set t P.5 unless otherwise djusted for multiple comprisons (Bonferroni corrections).

3 816 SOH, SANDHAM, CHAN TABLE 1. Distriution of Mlocclusion Types (Incisor [BSI] Clssifiction) of Totl Smple nd Among Ethnic Groups (), Mlocclusion Types: BSI Incisor Clssifiction Clss I Clss II/1 Clss II/2 Clss III Percentge () Mly (n 6) Indin* Totl (N 33) 48.1 ( ) 25.6 ( ) 3.5 ( ) 22. ( ) 51.7 ( ) 18.3 ( ) 3.3 ( ) 26.7 ( ) 38.1 ( ) 57.1 ( ) ( 16.1) 4.8 ( ) 48.1 ( ) 26.3 ( ) 3.2 ( ) 22.4 ( ) Indin sujects were more likely to hve ClssII/1 mlocclusion when compred with the others (P.1, OR 4.2, 1.7 to 1.3). Indictes British Stndrd Institute; CI, confidence intervl; OR, odds rtio. * P.5. TABLE 2. Totl smple (N 33) Mly (n 6) Indin Distriution of Overjet nd Overite (in mm) for the Totl Smple nd Among Ethnic Groups Overjet P.1 P.1* Overite Totl smple (N 33) Mly (n 6) Indin CI, confidence intervl; OR indictes odds rtio. Indins were more likely to hve overjet greter thn 6.5 mm (OR 8.1, ), *P P.875 RESULTS The distriution of mlocclusion types for the totl smple ccording to incisor clssifiction ws 48.1, 26.3, 22.4, nd 3.2 for Clss I, Clss II/1, Clss III, nd Clss II/2, respectively, s shown in Tle 1. Indin mles were four times more likely to hve Clss II/1 mlocclusion when compred with nd Mly mles (P.1, odds rtio [OR] 4.2, 1.7 to 1.3). No significnt difference in the distriution of mlocclusion types etween nd Mly ethnic groups ws found (P.5), implying tht the pttern of distriution of incisor occlusl sttus ws similr, lthough mles hd higher prevlence of Clss II/1 mlocclusion nd lower prevlence of Clss I mlocclusion when compred with Mly mles (Tle 1). Tle 2 shows the distriution of overjet nd overite mesurements. Thirty-six percent of the totl smple hd n overjet of two to three mm, which could e regrded s norml nteroposterior incisor reltionship, 2. hd overjet less thn two mm, nd 43.1 of four mm or more. Aout 6 of the totl smple hd

4 OCCLUSAL STATUS IN ASIAN MALE ADULTS 817 TABLE 3. Distriution of Crossites of Totl Smple nd Among Ethnic Groups in Frequencies nd Percentges Type of Crossite Anterior crossite Posterior uccl crossite Posterior lingul/scissor ite NS indictes not significnt. 35 (13.6) 4 (15.5) 35 (13.6) () Ethnicity Mly (n 6) 13 (21.7) 12 (2.) 5 (8.3) Indin 2 (.5) 5 (23.5) 4 (1.) Totl Smple (N 33) P 5 (14.7) 57 (16.8) 44 (13.).23 NS.41 NS.36 NS TABLE 4. Angle s Molr Reltionship Right Unclssified Clss I Clss II Clss III Left Unclssified Clss I Clss II Clss III Distriution of Angle s Molr Reltionships of Totl Smple nd Among Ethnic Groups in Frequencies nd Percentges NS indictes not significnt. 2 (.8) 12 (5.) 63 (24.4) 64 (24.8) 2 (.8) 135 (52.3) 63 (24.4) 58 (22.5) () Ethnicity Mly (n 6) 2 (3.3) 28 (46.7) 13 (21.7) 17 (28.3) 32 (53.3) 14 (23.3) 14 (23.3) Indin 1 (4.8) 12 (57.1) 7 (33.3) 1 (4.8) 13 (61.) 8 (38.1) Totl Smple (N 33) P 5 (1.5) 16 (4.) 83 (24.5) 82 (24.2) 2 (.6) 18 (53.1) 85 (25.1) 72 (21.2). NS.158 NS Missing Permnent Teeth nd Retined Deciduous Teeth of Totl Smple nd Among Ethnic Groups in Frequencies nd Percen- TABLE 5. tges Missing permnent teeth Retined deciduous teeth 34 (13.2) 7 (2.7) () Ethnicity Mly (n 6) 6 (1.) 3 (5.) Indin 7 (33.3) 1 (4.8) Totl Smple (N 33) P 47 (13.) 11 (3.2).4*.41 NS NS indictes not significnt. Pirwise comprisons (djusted P vlue.167) indicted tht Indin mle dults were more likely to hve missing permnent teeth (P.16, OR 3.5, 1.3 to.1). * P.5. overjet greter thn 6.5 mm tht could e considered s severe nd potentilly hndicpping. Indin mles were eight times more likely to hve n overjet greter thn 6.5 mm thn or Mly mles (P.1, OR 8.1, 2.7 to 23.8). Norml (1 2 mm) to modertely incresed ( 2 mmto 4 mm) overite ccounted for lrge proportion of the totl smple. Aout 4 hd openite wheres 11 hd deep overite greter thn four mm. Thus 15 of the totl smple hd overite tht could e regrded s severe devition from the norm. Miniml overite (.5 mm) ccounted for No significnt difference in overite distriution ws found mong the ethnic groups (P.5). The distriution of crossites is shown in Tle 3. Posterior uccl crossite (16.8) ws the most prevlent, followed y nterior crossite (14.7), nd posterior lingul/scissor ite (13.) for the totl smple. No significnt difference in the distriution of crossites ws found etween the ethnic groups, lthough nterior crossites nd posterior uccl crossites were more commonly seen in Mly nd Indin mles, respectively, when compred with mles. Tle 4 shows the Angle s molr reltionship of the totl smple nd ethnic groups. Clss I molr reltionship ws the most prevlent followed y Clss II nd III for oth right nd left sides. There ws no significnt difference in the distriution of molr reltionships etween the three ethnic groups (P.5). Cliniclly missing permnent teeth ccounted for 13. of the totl smple s shown in Tle 5. A significnt difference in the prevlence of missing teeth ws found e-

5 818 SOH, SANDHAM, CHAN Distriution of Mxillry nd Mndiulr Incisor Crowding of Totl Smple nd Among Ethnic Groups in Frequencies nd Percen- TABLE 6. tges Incisor Crowding Mxillry rch No crowding Mild crowding (1 3 mm) Moderte crowding (4 6 mm) Severe crowding ( 7 mm) Mndiulr rch No crowding Mild crowding (1 3 mm) Moderte crowding (4 6 mm) Severe crowding ( 7 mm) NS indictes not significnt. 4 (1.) 41 (15.) 86 (33.3) 82 (31.8) 8 (31.) 36 (14.) 67 (26.) 75 (2.1) () Ethnicity Mly (n 6) 13 (21.7) 6 (1.) 24 (4.) 17 (28.3) 11 (18.3) 12 (2.) 22 (36.7) 15 (25.) Indin 5 (23.8) 3 (14.3) (42.) 4 (1.) (42.) 2 (.5) 5 (23.8) 5 (23.8) Totl Smple (N 33) P 67 (1.8) 5 (14.7) 11 (35.1) 13 (3.4) 1 (2.5) 5 (14.7) 4 (27.7) 5 (28.).72 NS.23 NS tween the ethnic groups (P.5). Pirwise comprison (djusted P vlue t.167) found tht Indin mles were 3.5 times more likely to hve missing teeth when compred with nd Mly mles (P.16, OR 3.5, 1.3 to.1). Aout 3 of the totl smple hd retined deciduous teeth with no significnt difference found etween the ethnic groups (P.5). Moderte to severe incisor crowding of the mxillry nd mndiulr rch ccounted for 65.5 nd 55.7 of the totl smple, respectively, s shown in Tle 6. No significnt difference in the degree of crowding ws found mong the ethnic groups for oth mxillry nd mndiulr incisor crowding (P.5). DISCUSSION The study showed tht Asin men with Clss I mlocclusions were most prevlent on the sis of oth incisor BSI nd Angle s molr clssifiction. In comprison with previous Cucsin studies, 15 17,2 lower prevlence of Clss I mlocclusions in n Asin community ws found. However, much higher prevlence of Clss III mlocclusions ws found in this Asin smple when compred with its Cucsin counterprts. The clinicl impliction from this finding could men tht the orthodontic mngement of Clss III mlocclusions would e more commonly encountered in n Asin community. Although higher prevlence of Clss III mlocclusions hve een commonly ssocited with sujects hving heritge, this study found tht Mly ethnic group hd similr prevlence for Clss III mlocclusions. No significnt difference in the prevlence of mlocclusion types ws found etween nd Mly groups (P.5) implying tht the distriution of mlocclusion types could e regrded s similr. Woon et l 26 lso found no difference in the mlocclusion pttern etween nd Mly ethnic groups, lthough the results were otined from dolescents in multiethnic Asin community. Indin ethnic group in this study hd the highest prevlence of Clss II/1 mlocclusions (P.5) nd the lowest prevlence for Clss III mlocclusions mong the three ethnic groups. This pttern of distriution displyed y the Indin sugroup resemled tht in the results otined from recent study tht involved Cucsin sujects. Perhps the Indin sujects hd certin hereditry predisposition 27 to certin types of mlocclusions in mnner similr to Cucsins wheres nd Mlys shred certin common genetic trits. Vlidtion of this oservtion would require further investigtion in the re of genetics. Comprison of overjet mesurements found tht Indin ethnic group ws more likely to hve overjet greter thn 6.5 mm (P.1). This finding suggests tht Indin mles hd greter tendency to exhiit Clss II dentofcil pttern thn or Mly. The ssessment of molr reltionship in this study took into ccount missing permnent first upper or lower molrs s result of extrction sed on the oservtion of the residul extrction site, resored lveolr ridge seen on the study models, nd the dentl history scertined during dt collection. This ccounted for the unclssified ctegory of not more thn 2 s shown in Tle 4. The comprison of Angle s molr reltions of ethnic group with Hong Kong study 24 showed tht Clss II nd III molrs were more prevlent in this study. A higher prevlence of Clss I molr reltion ws found in the Hong Kong mle dults. However, this comprison ws t est n estimte ecuse of disprities in smple size nd reserch methodology. Indin dult mles were more likely to hve cliniclly

6 OCCLUSAL STATUS IN ASIAN MALE ADULTS 81 missing permnent teeth thn the other two ethnic groups (P.5). The cuses of missing teeth, oserved in this ge group, would e congenitl hypodonti nd extrction of teeth ecuse of cries or periodontl prolems. No ethnic difference ws found regrding retined deciduous teeth tht consisted of primry first nd second molrs. It my e speculted tht the permnent successors were either congenitlly missing or impcted (rdiogrphic ssessment ws not within the context of the study). Dentl crossites were oserved for ll ethnic groups. The long-term clinicl impliction of posterior lingul/scissor ite ws the supreruption of the unopposed nonfunctionl teeth nd the risk of losing them unless orthodontic correction ws performed. Posterior unilterl crossite hd een implicted s potentil cuse of skeletl nd functionl devition in children. 28,2 Thus, some of these Asin mle dults with posterior crossites could hve enefited from orthodontic intervention during their childhood yers in retrospect. A distinct common occlusl feture oserved in ll three ethnic groups ws the severity of incisor crowding. More thn 5 of the totl smple hd moderte to severe mxillry or mndiulr incisor crowding with no significnt ethnic difference. Thus, moderte to severe dentl displcements would e expected in the untreted dentitions of Asin mle dults, nd the need for extrction therpy would e common tretment pproch in dult orthodontics, should tretment e rendered. A crude comprison with the results from recent study suggests tht Asin men with severe incisor crowding tht could e potentilly hndicpping might e more prevlent thn untreted individuls found in the United Sttes. 3 A limittion of this study ws the reltively smll smple size nd its possile impct on ethnic group comprison. A goodness-of-fit test showed tht there ws no significnt difference (P.162) etween the oserved numer of sujects of the three ethnic groups of the smple (258, 6 Mlys, nd 21 Indins) nd the expected numer (27, 48 Mlys, nd 21 Indins) clculted from the popultion census reported y Shntkumr. 21 Sttisticlly, the ethnic proportions of the smple could e considered to e firly consistent in distriution. However, the uthors recognized this limittion nd would interpret the conclusions of this study with some degree of cution. Nevertheless, the study detected potentil difference in occlusl sttus mong Asin mle dults of different ethnicity. Much considertion ws given to the method chosen in defining nd reporting the occlusl sttus in this study, so tht some degree of comprison of findings could e mde with the pulished results from some of the previous studies. It ws evident from the literture tht there were differences in the methods of ssessing nd reporting occlusl trits. This hd mde the comprison of results tedious nd dependent on estimtion nd interprettion t est. A considertion for uniformity in the method of ssessing nd reporting occlusl sttus would e timely so tht meningful nd more ccurte comprisons could e mde when plnning future studies in this re of reserch. CONCLUSIONS The overll prevlence of mlocclusion in Asin mle dults on the sis of incisor (BSI) clssifiction ws 48.1, 26.3, 22.4, nd 3.2 for Clss I, Clss II/1, Clss III, nd Clss II/2, respectively. Angle s Clss I molr reltionship ws the most prevlent. 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