Originl Article Intrrch nd Interrch Reltionships of the Anterior Teeth nd Periodontl Conditions Pp Ibrhim Ngom ; Flou Digne b ; Henri Michel Benoist c ; Fn Thim d ABSTRACT This study ws undertken to investigte the ssocition between orthodontic nomlies nd periodontl conditions. Three prmeters of the intrrch reltionship on both dentl rches (displcement of contct point, crowding, nd spcing) nd four prmeters of interrch reltionship (overjet, open bite, crossbite, nd overbite) ssessed with either Index of Orthodontic Tretment Need or Index of Complexity, Outcome nd Need were correlted with prmeters of periodontl condition, ie, hygiene (Plque Index nd Retention Index), inflmmtion (gingivl inflmmtion nd Gingivl Bleeding Index), nd periodontl disese severity (pocket depth, clinicl ttchment loss, nd gingivl recession). In the min, wek but significnt correltions were found between certin prmeters of intrrch nd interrch reltionship nd some indices of periodontl conditions. Within the limittions of this study, it ws concluded tht providing orthodontic tretment on the ground of deleterious effect of mlocclusion nd mlpositioned teeth on periodontl condition is justified. (Angle Orthod 2006;76:236 242.) KEY WORDS: Intrrch reltionship; Interrch reltionship; Periodontl condition; Orthodontic indices; Periodontl indices INTRODUCTION The pst decdes hve witnessed stedy increse of children nd dults undergoing orthodontic tretment in industrilized countries. 1 The sme trend might be observed in developing countries. Improvement of fcil nd dentl esthetics nd of dentl helth nd function re routinely cited to justify the provision of orthodontic tretment nd form the cornerstone of some orthodontic indices. The Index of Orthodontic Tretment Need () 2 records tretment need on Assistnt Professor, Orthodontic Section, Deprtment of Dentistry, Fculty of Medicine, Phrmcy nd Dentistry, Université Cheikh Ant Diop, Dkr, Senegl. b Assistnt Professor, Orthodontic Section, Deprtment of Dentistry, Fculty of Medicine, Phrmcy nd Dentistry, Université Cheikh Ant Diop, Dkr, Senegl. c Assistnt Professor, Section of Periodontics, Deprtment of Dentistry, Fculty of Medicine, Phrmcy nd Dentistry, Université Cheikh Ant Diop, Dkr, Senegl. d Postgrdute student, Fculty of Medicine, Phrmcy nd Dentistry, Université Cheikh Ant Diop, Dkr, Senegl. Corresponding uthor: Pp Ibrhim Ngom, Deprtment of Dentistry, Fculty of Medicine, Phrmcy nd Dentistry, Université Cheikh Ant Diop, BP 45282 Dkr, Senegl (e-mil: ibrhim@refer.sn, e-mil: ngomibrhim@hotmil.com) Accepted: Februry 2005. Submitted: Jnury 2005. 2006 by The EH Angle Eduction nd Reserch Foundtion, Inc. the bsis of two components, Dentl Helth Component (DHC) nd n Aesthetic Component. The DHC intends to record the indiction for tretment on the ground of potentil deleterious effects of mlocclusion on the helth nd functioning of the dentition. At the time of its development, the uthors pointed out the uncertinty bout the reltive contribution tht ech occlusl trit mkes to the helth of the dentition nd emphsized the dptbility of the index ccording to the emergence of further reserch findings on this re. 2 The Index of Complexity, Outcome nd Need () ws developed lter nd is bsed on the consensus opinion of eight Europen countries nd the United Sttes. 3 The etiology nd pthogenesis of periodontl disese re known to be multifctoril, but dentl plque is recognized s n essentil precursor. 4,5 Hence, ny fctor presumed to promote plque retention or to mke difficult its removl might contribute to the locl risk of periodontl disese. For instnce, crowding of teeth cretes res hrdly ccessible to tooth brushing nd hs been recognized to mke thorough clening of the teeth lborious. 6 8 Vrious types of mlocclusions hve lso been correlted to incresed plque indices. 9,10 On the other hnd, mny investigtions filed to demonstrte ny significnt correltion between tooth irregulrities nd periodontl stte. 11 In 236
ORTHODONTIC ANOMALIES AND PERIODONTAL CONDITION TABLE 1. Scoring System for the Intrrch Reltionship With nd Scores CPD Crowding Spcing 0 No CPD 2 mm 2 mm 1 1 mm CPD 0 mm 2.1 to 5 mm 2.1 to 5 mm 2 2 mm CPD 1 mm 5.1 to 9 mm 5.1 to 9 mm 3 4 mm CPD 2 mm 9.1 to 13 mm 9.1 to 13 mm 4 4 mm 13.1 to 17 mm 5 17 mm indictes Index of Orthodontic Tretment Need;, Index of Complexity, Outcome nd Need; CPD, Contct Point Displcement. ddition, some uthors stressed tht the enhncement provided by orthodontic tretment in terms of periodontl helth my be of minor importnce compred with mintennce of good orl hygiene. 12 Also, recently, Geiger 13 wondered bout the vilble findings on the correltion between mlocclusion nd periodontl disese nd emphsized the need for dditionl quntittive studies to vlidte the predictbility of mlocclusion s n etiologic fctor of periodontl disese. Towrd these ends, this study ws undertken to further investigte the correltion between the intrrch nd interrch reltionships of the nterior teeth s ssessed by the nd the nd some prmeters of periodontl conditions, ie, hygiene, inflmmtion, disese severity, nd tretment need. MATERIALS AND METHODS Subjects The study popultion consisted of smple of 101 young dults (51 mles nd 50 femles), ged 20 to 35 yers (men 25.44 SD 3.00 yers) with no history of orthodontic tretment. They were students or techers of the Deprtment of Dentistry, Fculty of Medicine, Phrmcy nd Dentistry t University Cheikh Ant Diop of Dkr (Senegl). They prticipted in the study on voluntry bsis fter receiving comprehensive informtion bout the ims nd design of the study before its strt nd signed n informed consent. Before enrollment in the study, informtion regrding orl hygiene hbits nd knowledge bout orl hygiene prctice were obtined directly from ech subject. Inclusion criteri To be included in the study, subjects needed to fulfill the following criteri: possession of the six nturl teeth of the nterior sextnt (incisors nd cnines) in ech rch; mnul tooth brushing t lest twice dily 237 right hnded; nd thorough knowledge of useful orl hygiene methods. Noninclusion criteri These included known fctors likely to influence periodontl condition, ie, smoking, pregnncy, mouth brething, nd dibetes. In ddition, ll subjects who hd undergone professionl plque removl nd scling in the pst five months were not included in the study. Assessment of periodontl condition The study subjects were exmined for evlution of periodontl conditions in dentl office under optiml conditions with mouth mirror nd periodontl probe. Prmeters relted to the periodontl sttus were ssessed directly by one of the uthors in the upper nd lower nterior sextnt (incisors nd cnines of both the mxillry nd the mndibulr rches). These included orl hygiene, gingivl inflmmtion, nd severity of periodontl disese. Orl hygiene. The orl hygiene sttus ws evluted by mesuring the mount of soft nd minerlized deposits present on the tooth surfce. Plque nd clculus were ssessed on ll four surfces (lbil, lingul/pltl, mesil, nd distl) of incisors nd cnines in both the lower nd upper rches by the Plque Index (PlI) nd the Retention Index (RI). 14 The PlI nd RI were recorded s described by Loe 14 except tht for RI only clculus ws tken into ccount. Cvities nd dentl restortions were not considered. The plque nd retention scores from the four res of ech tooth were dded nd divided by four to give the PI nd the RI for the tooth. The PII nd the RI for the nterior sextnt of ech rch were obtined by summing the scores for individul teeth (incisors nd cnines) nd divided by six (the number of teeth in ech sextnt). Gingivl inflmmtion. The degree of gingivl inflmmtion ws ssessed with the Gingivl Index (GI) 14 nd the Gingivl Bleeding Index (GBI). 15 For the GI, 14 ech of the four gingivl res of the teeth (lbil, lingul/pltl, mesil, nd distl) is given score from 0 to 3, which represent the GI for the re. The scores from the four res of the tooth were dded nd divided by four to give the GI for the tooth. The scores for individul teeth of ech rch were summed nd divided by six to obtin the GI for the nterior sextnt. The GBI 15 is recorded dichotomously fter gentle probing of the mesil, midline, nd distl on the lbil nd lingul/pltl surfces of ech of the trgeted teeth. GBI 0 corresponds to n bsence of bleeding nd 1 to presence of bleeding, 15 seconds fter the removl of the probe. The GBI for ech tooth is cl-
238 NGOM, DIAGNE, BENOIST, THIAM TABLE 2. Scores Scoring System for the Interrch Reltionship With nd Crossbite Overbite 0 No crossbite 1 Crossbite present Overbite 1/3 2 Discrepncy b 1mm 3.5 mm 1/3 to 2/3 coverge c 3 2 mm Discrepncy b 1 mm Full coverge c 2/3 coverge c 3/3 4 Discrepncy b 2 mm Full coverge c GP trum Full coverge c 5 indictes Index of Orthodontic Tretment Need;, Index of Complexity, Outcome nd Need. b Discrepncy between retruded contct point nd intercuspl position. c Lower incisor coverge. culted by summing the scores for the six res nd by dividing it by six. The GBI for the sextnt is clculted by dividing the score of the teeth by six. Disese severity. The extent of periodontl disese severity ws ssessed by mesuring the pocket depth (PD), the clinicl ttchment loss (CAL), nd the gingivl recession (GR) with Willim probe on six res of the teeth of the upper nd lower nterior sextnt, ie, mesil, midline, nd distl on the fcil nd lingul/ pltl surfces. The score for the sextnt is obtined by verging the findings for the six teeth. Intrrch nd interrch reltionship prmeters The intrrch nd interrch reltionship ws ssessed on the nterior sextnt (teeth 13 to 23 nd 33 to 43) by either 2 or 3 (or both) depending on the occlusl trits of interest. The recording of the nd scores ws performed with disposble DHC ruler nd n ordinry millimeter ruler by one of the uthors, who ws trined, nd clibrted in the use of these occlusl indices. Scoring protocols for nd re given in Tbles 1 nd 2. The extent of the relibility of the ssessment of the periodontl condition nd the intrrch/interrch reltionship ws ssessed by performing the sme ssessment on rndom subsmple of 20 subjects with minimum intervl of one month. Sttisticl nlysis The set of vribles used in this study re summrized in Tble 3. Wilcoxon mtched pirs signed rnk test nd kpp sttistics were used to test the relibility of the ssessment of periodontl condition nd intrrch nd interrch reltionship, respectively. Differences between mles nd femles with respect to periodontl condition score were tested with Mnn- Whitney U-test. Spermn rnk correltion ws used to test the ssocition between the periodontl condition nd the intrrch nd the interrch reltionship. All tests were crried out by SPSS (Relese 11, 2001, Chicgo, Ill). Significnce ws set t the 5% level. RESULTS None of the tests for relibility using Wilcoxon mtched pirs test were significnt t the 5% level. Kpp sttistics ws, respectively, 0.87 nd 0.91 for the ssessment of intrrch nd interrch reltion with the nd the. The periodontl sttus of the mle nd femle subjects long with the corresponding interprettion is shown in Tble 4. Overll, it ppers tht the study subjects hd verge periodontl conditions. Femles generlly hd better periodontl condition thn mles, but the difference ws significnt only for the RI, which tkes into ccount only the mount of clculus present on the tooth surfce. About one third of the subjects hve t lest some kind of orthodontic nomly. Tbles 5 nd 6 show the distribution of the different fetures of the intrrch nd the interrch reltionship s ssessed by nd. Correltions between prmeters of periodontl condition nd intrrch reltionship in the mxill nd the mndible re listed in Tble 7. Wek but significnt correltions were found between contct point displcement nd the PlI nd the GI in both the mxill nd the mndible. Crowding is significntly correlted with lmost ll prmeters of periodontl condition in the mndibulr rch but not in the mxillry rch. Overll, spcing is negtively correlted to periodontl condition, but this correltion is not significnt. The periodontl disese severity, s reflected by PD, clinicl ttchment loss, nd GR, is not significntly correlted with the prmeters of intrrch reltionship except with crowding of teeth. Tble 8 shows the correltions between the interrch reltionship nd the periodontl sttus. Open bite ssessed by either the or the is often positively nd significntly correlted with the prmeters of periodontl condition. The only exception is with GR with which it is negtively correlted. The prmeters
ORTHODONTIC ANOMALIES AND PERIODONTAL CONDITION 239 TABLE 2. Extended Open Bite Overjet 1mm OB 0mm 1 mm 6mm OJ 3.5 mm 2mm OB 1mm 2mm OB 1.1 mm 6 mm OJ 3.5 mm 4mm OB 2mm 4mm OB 2.1 mm 9 mm OJ 6mm OB 4mm 4 mm 9 mm TABLE 3. Summry of the Vribles Used Vribles Type of Vrible Unit Periodontl condition Hygiene PlI Ordinl Unitless RI Ordinl Unitless Gingivl inflmmtion GI Ordinl Unitless GBI Ordinl Unitless Periodontl disese severity PD Scle mm CAL Scle mm GR Scle mm Intrrch nd interrch reltionship Intrrch reltionship CPD Ordinl mm Spcing Ordinl mm Crowding Ordinl mm Interrch reltionship Crossbite Ordinl mm Open bite Ordinl mm Overbite Ordinl mm Overjet Ordinl mm Crossbite Ordinl mm Overbite Ordinl mm Open bite Ordinl mm Demogrphic dt Age Scle Yers Gender Nominl Unitless PlI indictes Plque Index; RI, Retention Index; GI, Gingivl Index; GBI, Gingivl Bleeding Index; PD, pocket depth; CAL clinicl ttchment loss; GR, gingivl recession; CPD, contct point displcement; IOCN, Index of Complexity, Outcome nd Need;, Index of Orthodontic Tretment Need. of disese severity re generlly significntly correlted with those of interrch reltionship (Tble 8). DISCUSSION Methodologicl considertions nd limittions of this study This study is cross-sectionl nd observtionl by nture. At best, the scope of such study is limited to demonstrting correltion between exposition nd presence or bsence of disese or condition. Hence, on the bsis of the present findings, one cnnot speculte bout cusl reltionship between orthodontic nomlies nd periodontl condition. Becuse of the multifctoril nture of periodontl disese, longitudinl studies controlling for most confounding effects re necessry. However, it should be borne in mind tht, with respect to the current subject mtter, longitudinl studies my be probbly highly unethicl nd methodologiclly difficult to crry out. Accordingly, this study nd its predecessors cn provide vluble indictions on the influence of orthodontic nomlies on periodontl condition. Evidence exists to suggest close reltionship between eductionl level nd qulity of orl hygiene. 16 A poor dentl ttendnce pttern hs lso been found to be ssocited with higher frequency of periodontitis. 17 These findings dictted the choice of the study popultion within the dentl profession. It is ssumed tht the study subjects hve the necessry skills nd motivtion to remove suprgingivl plque nd subsequently to prevent the onset of gingivitis. It ddition, they my hve the sme level of wreness regrding these confounding fctors. The restriction of the study to the nterior teeth proceeds lso from the need to reduce the possible confounding effect of mnul dexterity in tooth brushing. Also, the noninclusion of lefthnded subjects, pregnnt women, nd smokers nd
240 NGOM, DIAGNE, BENOIST, THIAM TABLE 4. Periodontl Sttus of the Subjects nd Interprettion. Comprison Between Mle nd Femle Subjects Periodontl Condition (Men SD) Mle Interprettion (Men SD) Femle Interprettion Mnn-Whitney U-test P Vlue Upper rch PlI 0.99 0.53 Averge plque control 0.84 0.40 Averge plque control.16 RI 0.20 0.31 Slight mount of clculus 0.10 0.29 Slight mount of clculus.00** GI 0.42 0.44 Mild gingivl inflmmtion 0.30 0.36 Mild gingivl inflmmtion.14 GBI 0.10 0.18 Mild gingivl inflmmtion 0.08 0.12 Mild gingivl inflmmtion.94 CAL 3.26 1.48 3.05 0.92.55 PD 3.12 1.04 Shllow pockets 3.03 0.84 Shllow pockets.77 GR 0.32 1.34 0.05 0.42.30 PlI 1.22 0.65 Averge plque control 0.99 0.56 Averge plque control.09 RI 0.62 0.71 Slight mount of clculus 0.40 0.64 Slight mount of clculus.04* Lower rch GI 0.66 0.56 Mild gingivl inflmmtion 0.53 0.61 Mild gingivl inflmmtion.08 GBI 0.19 0.27 Mild gingivl inflmmtion 0.15 0.22 Mild gingivl inflmmtion.60 CAL 3.22 1.09 3.25 1.05.92 PD 2.98 1.02 Shllow pockets 3.2 1.03 Shllow pockets.53 GR 0.58 1.26 0.25 0.89.14 PlI indictes Plque Index; RI, Retention Index. ** Difference significnt t.001 level. TABLE 5. Distribution of Fetures of the Intrrch Reltionship Within the Study Subjects CPD Crowding Spcing Scores: 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 Upper rch 7 26 31 26 11 73 19 6 3 0 67 16 11 7 0 Lower rch 5 19 41 28 8 49 37 10 4 1 81 11 5 4 0 indictes Index of Orthodontic Tretment Need;, Index of Complexity, Outcome nd Need; CPD, Contct point displcement. TABLE 6. Distribution of Fetures of the Interrch Reltionship Within the Study Subjects Crossbite Overbite Open bite Overjet Vlue 0 71 70 82 81 83 85 66 1 0 30 0 14 0 3 0 2 15 18 6 8 4 22 3 6 1 5 4 6 4 9 0 5 5 7 5 0 0 0 indictes Index of Orthodontic Tretment Need;, Index of Complexity, Outcome nd Need. the inclusion of subjects of reltively close ge brcket, rises from the sme concerns. However, these precutions hve been tken t the expense of losing the possibility of generlizing the findings to other res of the mouth nd to other subgroups of popultion. The subjects included in this study hve climed to brush their teeth t lest twice dily nd to ttend dentl visits regulrly. However, our estimtes of dentl hygiene nd gingivl inflmmtion in this popultion reflect verge periodontl condition (Tble 4). It ppers tht in the context of this study, the use of common orl hygiene regimen is not synonymous with high stndrd of periodontl condition. There ws no difference in this study between mles nd femles regrding periodontl condition except for the RI, which ws significntly more importnt in mles. Intrrch reltionship nd periodontl condition Vrying degrees of correltion hve been found between intrrch reltionship nd periodontl condition depending on the rch nd the indices tken into ccount. Overll, it ppers tht, despite norml hy-
ORTHODONTIC ANOMALIES AND PERIODONTAL CONDITION 241 TABLE 7. Intrrch reltionship Spermn Rnk Order Correltions Between Periodontl Condition nd Intrrch Reltionship in the Upper nd the Lower Dentl Arch PlI Hygiene RI Periodontl Condition Gingivl Inflmmtion GI GBI Periodontl Disese Severity CAL PD GR Upper rch CPD () 0.225* 0.105 0.212* 0.134 0.115 0.111 0.042 Crowding () 0.101 0.177 0.111 0.076 0.087 0.055 0.017 Spcing () 0.014 0.162 0.171 0.056 0.100 0.082 0.011 Lower rch CPD () 0.338** 0.068 0.263** 0.160 0.097 0.192 0.026 Crowding () 0.297** 0.192 0.377*** 0.310** 0.224* 0.240* 0.045 Spcing () 0.047 0.028 0.131 0.147 0.054 0.087 0.014 PlI indictes Plque Index; RI, Retention Index; GI, Gingivl Index; GBI, Gingivl Bleeding Index; CAL clinicl ttchment loss; PD, pocket depth; GR, gingivl recession. * Correltion is significnt t.05 level (two-tiled); ** Correltion is significnt t.01 level (two-tiled); *** Correltion is significnt t.001 (two-tiled). TABLE 8. Intrrch reltionship Spermn Rnk Order Correltions Between Periodontl Condition nd Interrch Reltionship s Assessed by nd PlI Hygiene RI Periodontl Condition Gingivl Inflmmtion GI GBI Periodontl Disese Severity CAL PD GR Overjet 0.216* 0.153 0.139 0.157 0.095 0.115 0.001 Crossbite 0.051 0.097 0.017 0.094 0.081 0.037 0.223* Overbite 0.223* 0.164 0.169 0.198* 0.290** 0.233* 0.166 Open bite 0.154 0.188 0.236* 0.332** 0.197* 0.232* 0.131 Crossbite 0.039 0.084 0.029 0.063 0.073 0.024 0.198* Overbite 0.164 0.079 0.126 0.135 0.259** 0.210* 0.161 Open bite 0.221* 0.236* 0.299** 0.393*** 0.249* 0.273** 0.112 PlI indictes Plque Index; RI, Retention Index; GI, Gingivl Index; GBI, Gingivl Bleeding Index; CAL clinicl ttchment loss; PD, pocket depth; GR, gingivl recession. * Correltion is significnt t.05 level (two-tiled); ** Correltion is significnt t.01 level (two-tiled); *** Correltion is significnt t.001 (two-tiled). giene regimen, the presence of mlpositioned nd crowded teeth in the mndibulr rch is ssocited with difficulties in plque removl nd gingivl inflmmtion. On the other hnd, these prmeters rnked lower in the mxillry teeth. Comprisons with previous studies re complicted by virtue of the differences in methodologicl pproches nd the indices used to ssess both the periodontl nd the occlusl conditions. Ingervll et l 11 lso studied the reltionship between crowding of teeth nd gingivl condition in smller smple of dentl students of lmost the sme ge brcket, s in subjects of this study. They found tht crowding of teeth (tooth displced by two mm or rotted for t lest 15 ) did not fvor plque ccumultion on proximl tooth surfces nd influenced gingivl inflmmtion only slightly. 11 Geiger et l 18 lso found no significnt correltion between crowding nd periodontl condition. On the other hnd, Buckley 8 in study of 300 teengers reported low but significnt correltion in the rnge of tht found in this study between lower incisor crowding s ssessed by the Occlusl Feture Index, the PlI nd the GI. Although they did not rise to levels high enough to ttin significnce, the negtive correltions between spcing nd periodontl prmeters indicte trend towrd more fvorble periodontl condition in subjects with spced dentition. Previous studies 19,20 reported the sme trend. These findings question the indiction for spce closure specificlly for esthetic resons, lthough it might contribute to mintining dentl helth. The reson why crowding, lthough significntly correlted with hygiene nd inflmmtion, is not correlted to disese severity is elusive. However, it is noteworthy tht lthough gingivitis must precede periodontitis, not ll gingivitis progresses to periodontitis. 21 Interrch reltionship nd periodontl condition Concerning the interrch reltionship, the results of this study indicte tht open bite is more lible to induce morbidity with regrd to the periodontium. This issue hs not been investigted before becuse we found no study in the literture deling with the influence of open bite on periodontl condition. Crossbite, in this study correltes significntly with
242 NGOM, DIAGNE, BENOIST, THIAM GR but not with the other periodontl prmeters studied. These results did not support the findings of l- Jsser nd Hshim 9 nd Hshim nd l-jsser, 10 who reported significnt reltionship between crossbite nd PlI, GI, nd PD in smller nd younger smple. However, their study popultion my hve differed with tht of this study in terms of ge nd orl hygiene wreness. Silness nd Roynstrnd 22 lso found tht subjects with crossbite teeth hd higher periodontl scores thn those without. At lst, in n extensive study involving 516 subjects, Geiger nd Wssermn 23 reported no consistent ssocition between this type of mlocclusion nd periodontl disese. The correltion found in this study between crossbite nd GR could be explined by primry occlusl trum. In fct, the teeth in crossbite my be often in premture contct in centric reltion nd t the end of closing phse during mstiction. The occlusl lods in such cse re not properly distributed. Subsequently, the resistnce of the periodontl tissues is overwhelmed which my led to occlusl trum nd GR. Overbite ssessed with either or ws significntly correlted with clinicl ttchment loss nd PD in this study but not with the prmeters of hygiene nd inflmmtion. These findings contrst with the report of Buckley 8 who used PlI nd GI s periodontl condition index nd n ssessment of overbite similr to tht of. Overjet ws wekly but significntly correlted with PlI but not with the other indices of periodontl condition. Dvies, 24 in report of the preliminry results of n extensive longitudinl study involving nine hundred nd fourteen 12-yer-old children lso reported significnt ssocition between men plque score nd nterior overjet. Geiger et l 25 found slight ssocition between severe nterior overjet nd periodontl disese. In contrst, the results of Buckley s 8 investigtion demonstrte n bsence of correltion between incisl overjet nd plque nd gingivl index. 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