Eruption of the permanent maxillary canines in relation to mandibular second molar maturity

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1 Originl Article Eruption of the permnent mxillry cnines in reltion to mndibulr second molr mturity Giuseppe Perinetti ; Mrilen Cllovi b ; Stefno Slgrello c ; Mtteo Bisotto d ; Luc Contrdo d ABSTRACT Objective: To evlute the timing of spontneous mxillry cnine eruption in reltion to stges of mndibulr second molr mturtion. Potentil confounding effects from such fctors s ge, growth phse, nd fcil fetures were lso explored. Subjects nd Methods: A smple of 106 helthy subjects (48 femles nd 58 mles; ge rnge, yers) with both permnent mxillry cnines during the finl phse of introrl eruption were included. Mndibulr second molr mturtion (stges E to H) ws ssessed ccording to the method of Demirjin. Skeletl mturity ws determined using the cervicl vertebrl mturtionl (CVM) method. Fcil verticl nd sgittl reltionships were evluted by recording the Sell- Nsion/mndibulr plne (SN/MP) ngle nd the ANB ngle. An ordered multiple logistic regression ws run to evlute djusted correltion of ech prmeter with the mndibulr second molr mturtionl stge. Results: Overll, the prevlence of the different second molr mturtionl stges ws 36.8%, 37.8%, nd 27.4% for stges E, F nd G, respectively. According to the regression model, this reltion ws not influenced by sex, CVM stge, SN/MP ngle, nd ANB ngle. Conclusions: Irrespective of sex, growth phse, nd fcil fetures, the mturtionl stge of the mndibulr second molr my be relible indictor for the timing of spontneous eruption of the mxillry cnine. (Angle Orthod. 2013;83: ) KEY WORDS: Dentl mturtion; Cnine eruption; Dignosis; Timing; Orthodontics INTRODUCTION Permnent cnines hve primry roles in determining functionl occlusion nd plesnt smile, nd disturbnces of norml development nd eruption cn hve mjor consequences (for review, see Bedoy Reserch Fellow, Deprtment of Medicl, Surgicl nd Helth Sciences, School of Dentistry, University of Trieste, Trieste, Itly. b Resident, Deprtment of Medicl, Surgicl nd Helth Sciences, School of Dentistry, University of Trieste, Trieste, Itly. c Associte Professor, Deprtment of Orl Sciences, University of Bresci, Bresci, Itly. d Assistnt Professor, Deprtment of Medicl, Surgicl nd Helth Sciences, School of Dentistry, University of Trieste, Trieste, Itly. Corresponding uthor: Giuseppe Perinetti, DDS, MS, PhD, Struttur Compless di Clinic Odontoitric e Stomtologic, Ospedle Mggiore, Pizz Ospitle 1, Trieste, Friuli Venezi Giuli, Itly (e-mil: G.Perinetti@fmc.units.it) Accepted: December Submitted: September Published Online: Jnury 9, 2013 G 2013 by The EH Angle Eduction nd Reserch Foundtion, Inc. nd Prk 1 ). Regrding the mxillry cnine, n importnt nd effective tretment modlity to prevent impction is bsed on intercepting nd eliminting ny fctor tht my interfere with eruption. 2 However, lthough precise dignosis of delyed eruption, tht is, displcement or impction, is needed, this cnnot be done on the bsis of chronologicl ge or phse of dentition. 3,4 On the contrry, erly studies, 3,4 confirmed by recent evidence, 5 hve shown tht permnent mxillry cnines undergo spontneous eruption until lte puberty, tht is, during prepubertl nd pubertl growth phses. These results were determined using the stturl height pek 3,4 or the mturtion of the hnd nd wrist or cervicl vertebre 5 methods to identify the pubertl growth-spurt period in individul subjects. Therefore, the use of indictors of the timing of spontneous mxillry cnine eruption hs been dvocted s n djunct to the dignosis nd mngement of cnine displcement/impction. 5 Of interest, recent primry study 6 on white subjects nd met-nlysis 7 on different ethnicities hve consistently shown significnt ssocition of the complete mturtion, tht is, complete root formtion, of the mndibulr second molr with ttinment of 578 DOI: /

2 CANINE ERUPTION AND SECOND MOLAR MATURITY 579 postpubertl growth phse. Therefore, considering how the mxillry cnine eruption nd mndibulr second molr mturtion re both prts of the sme whole dentition development, reltion between the two processes my be hypothesized. Thus, considering the relevnt clinicl implictions reported erlier, the present study focused on the reltion between the spontneous eruption of the permnent mxillry cnine nd the mturtion of the mndibulr second molr to propose the monitoring of the ltter s mens of predicting the timing for the spontneous eruption of the former in individul subjects. Moreover, the potentil confounding effects from such fctors s ge, growth phse, nd fcil fetures were lso explored. MATERIALS AND METHODS A smple of 106 subjects (48 femles nd 58 mles; ge rnge, yers) t the Unit of Orthodontics of the University of Trieste with both permnent mxillry cnines during the finl phse of introrl eruption were retrospectively included. Signed informed consent ws obtined from the prents of the subjects before entry into the study, nd the protocol ws reviewed nd pproved by the locl ethicl committee. Thirty-three subjects of the present smple were included in previous study 6 with different purpose. At their first clinicl exmintion, introrl photogrphs, dentl pnormic rdiogrph, nd lterl cephlogrm were obtined from ech subject s prt of the pretretment clinicl recording. The following inclusion criteri were observed: (1) white ethnicity, (2) good generl helth with bsence of ny nutritionl or developmentl problems, (3) never orthodonticlly treted, (4) negtive for ny dentl or fcil nomly (including mssive cries, tooth loss, multiple genesis), (5) no history of previous trum in the orofcil region, nd (6) bsence of ny pthologic obstcles to the eruption pthwy of the mxillry cnines, such s odontoms, cysts, or supernumerries. 5 Moreover, only ptients with miniml crowding or differentil eruption degree between the two contrlterl cnines were considered. In cse of slight dely in the eruption of one cnine over the other, the less erupted tooth ws considered. The finl phse of cnine eruption ws defined s previously reported. 8 Briefly, it ws the emergence of the cnine from the initil ppernce of the tip of the cusp in the dentl rch to 1-mm distnce of the tip of the cusp from the mxillry occlusl plne (trced on the pnormic rdiogrph). Skeletl mturity ws ssessed through the cervicl vertebrl mturtionl (CVM) method. 9 This method Figure 1. Mturtionl stges of the mndibulr second molr ccording to Demirjin et l. 10 (stges E to H). comprises six stges (CS1 to CS6). An experienced orthodontist, blinded to the ge nd sex of the subjects, ssessed the skeletl mturity of the subjects. Finlly, the subjects were clustered, ccording to their growth phses, s prepubertl (CS1 nd CS2), pubertl (CS3 nd CS4), nd postpubertl (CS5 nd CS6). Assessment of Mndibulr Second Molr Mturity Mndibulr second molr mturity (Figure 1) ws ssessed through the clcifiction stges, ccording to the method of Demirjin et l. 10 (stges E to H), from the pnormic rdiogrphs of the left-side mndibulr teeth. Alterntively, when the left side ws not clerly visible, the right side ws ssessed. Briefly, these stges re defined s follows: Stge E: (1) The wlls of the pulp chmber form stright lines, the continuity of which is broken by the presence of the pulp horn, which is lrger thn in the previous stge; nd (2) the root length is less thn the crown height. Stge F: (1) The wlls of the pulp chmber form more or less isosceles tringle, with the pex ending in funnel shpe; nd (2) the root length is equl to or greter thn the crown height. Stge G: The wlls of the root cnl re prllel, nd its picl end is still prtilly open. Stge H: (1) The picl end of the root cnl is completely closed; nd (2) the periodontl membrne hs uniform width round the root nd the pex. An experienced orthodontist, blinded to the skeletl mturtion stges nd the ge nd sex of the subjects, ssessed the dentl mturity of the mndibulr second molrs using the distl root s the reference structure. Cephlometric Recordings Fcil verticl nd sgittl reltionships were evluted by recording the Sell-Nsion/mndibulr plne

3 580 PERINETTI, CALLOVI, SALGARELLO, BIASOTTO, CONTARDO Tble 1. Chronologicl Age, SN/MP Angle, nd ANB Angle for Femles (n 5 48) nd Mles (n 5 58) Femles Prmeter Men 6 SD Rnge Men 6 SD Rnge Diff. Age (yers) NS SN/MP ngle (u) NS ANB ngle (u) NS SN/MP indictes Sell-Nsion/mndibulr plne; SD, stndrd devition of the men; Diff., significnce of the difference between the sexes; NS, not sttisticlly significntly different. Mles (SN/MP) ngle nd the ANB ngle, respectively. The mndibulr plne ws defined s the Gonion-Gnthion line. The cephlogrms were hnd trced by single investigtor. Cephlometric softwre (Viewbox, version 3.0, dhal Softwre, Kifissi, Greece) ws used for mesurements on digitized cephlogrms. Subjects were not clustered s hyper-/normo-/hypodivergent or s skeletl Clss I/II/III s previously done. 5,11 Insted, multiple regression models were used to evlute the effects of these vribles on the correltions between the mxillry cnine eruption nd mndibulr second molr mturtion. Repetbility nd Method Error Clcultion The following nlyses were performed on 20 pirs of recordings rndomly selected. Repetbility for the ssessed mturtionl stges of both the cervicl vertebre nd mndibulr second molr ws evluted through weighted kpp coefficient. This kpp coefficient ws weighted linerly s this mkes the coefficient less sensitive to the number of ctegories 12 or stges, thus voiding bises in the interprettion of the results. A weighted kpp coefficient bove 0.80 stnds for n lmost perfect repetbility. 13 Method error of the recordings for both SN/MP ngle nd ANB ngle ws quntified though the method of moments vrince estimtor, 14 which hs the dvntges of not being ffected by ny unknown bis, tht is, systemtic errors, between pirs of mesurements. 14 Sttisticl Anlysis Normlity of the dt sets nd the equlity of vrince mong them were evluted by the Shpiro-Wilk test nd Levene test, respectively. Between the sexes, the sttisticl significnce of the differences in men ges, SN/MP ngle, nd ANB ngle ws evluted by n independent smple t-test, wheres those for the distributions of the growth phses (s prepubertl nd pubertl) nd the second molr mturtionl stges (s E, F, nd G) were evluted by x 2 test. Subsequently, the djusted correltions of these vribles with the dentl mturtionl stges were evluted by multiple ordered logistic regression, which is regression model for ordinl dependent vribles. In prticulr, the following explntory vribles (ctegories) were entered in the model: ge, sex (femles, mles), growth phse (prepubertl, pubertl), SN/MP ngle, nd ANB ngle. Ech of the three dentl mturtionl stges (E, F, nd G) ws the ctegory of the dependent vrible, with stge G s the reference ctegory. For sex nd growth phse, reference ctegories were mles nd pubertl, respectively. Briefly, the bet coefficients retrieved by this ordinl regression model re the ordered log odds of being in more mture stge of the mndibulr second molr for one-unit increse in SN/MP ngle or ANB ngle (continuous vrible) or when belonging to nonreference ctegory (ie, femles vs mles nd prepubertl vs pubertl), given ll of the other vribles in the model re held constnt. Moreover, dt from previous investigtion 6 on dentl mturtion were retrieved, nd mens nd stndrd errors of the chronologicl ges of the subjects t ech mturtionl stge of the mndibulr second molr were plotted for femles nd mles. This ws cross-sectionl study on lrge smple of subjects; therefore, the difference in men ges between the subjects, clustered ccording to two consecutive mturtionl stges, my be considered s the time required for the investigted tooth to mture from one stge to the next, especilly from stge E to stge G. A P vlue less thn.05 ws used for rejection of the null hypothesis. RESULTS For pprisl of the stges of both cervicl vertebre nd second molr mturtionl stges, the weighted kpp coefficients for repetbility were bove The method error for the cephlometric recordings ws lower thn 1u. The men ges of the subjects, long with the SN/ MP ngle nd ANB ngle, for femles nd mles re summrized in Tble 1. All of these prmeters were similr between the sexes, nd there were no significnt differences. The reltive distributions of the different growth phses nd second molr mturtionl stges for femles nd mles re summrized in Tble 2. A

4 CANINE ERUPTION AND SECOND MOLAR MATURITY 581 Tble 2. Reltive Distributions of the Different Growth Phses nd Second Molr Mturtionl Stges for Femles nd Mles Prmeter Femles, N (%) Mles, N (%) Diff. Growth phse Prepubertl 16 (33.3) 40 (69.0) P,.001 Pubertl 32 (66.7) 18 (31.0) Second molr mturtion Stge E 22 (45.8) 17 (29.3) NS Stge F 14 (29.2) 26 (44.8) Stge G 12 (25.0) 15 (25.9) No subjects in the postpubertl growth phse or mndibulr second molr t stge H were seen. Diff. indictes significnce of the difference between the sexes; NS, not sttisticlly significntly different. greter percentge of subjects in the pubertl growth phse ws seen for femles (66.7%) compred with mles (31.0%; P,.01). Overll, the prevlences of the different second molr mturtionl stges were 36.8%, 37.8%, nd 27.4% for stges E, F, nd G, respectively. No stge H ws seen, nd the distributions of the other stges were similr between the sexes, with no significnt difference. The ordered multiple regression model for the ssocition of ech explntory vrible with the second molr mturtionl stge is summrized in Tble 3. With the exception of ge (b, 0.543; P,.01), none of the explntory vrible yielded sttisticlly significnt interction with the second molr mturity. Chronologicl ges mong the different mndibulr second molr mturtionl stges for femles nd mles s retrieved from previously investigted smple 6 re shown in Figure 2. The overll men (stndrd error) vlues were , , , , nd yers for stges D, E, F, G, nd H, respectively. Men time intervls between stges E to F nd stges F to G were 1.5 nd 1.6 yers, respectively. The slight differences seen between femles nd mles were not sttisticlly significnt. DISCUSSION This cross-sectionl study ws undertken to evlute the reltion between the spontneous eruption of mxillry cnine nd mndibulr second molr Figure 2. Chronologicl ges mong the different mndibulr second molr mturtionl stges for femles (N 5 208) nd mles (N 5 146). Dt re presented s men 6 stndrd error of the men. Dt were retrieved from cses included in previous study. 6 mturtion. All the subjects hd cnine eruption of the mndibulr second molr within mturtionl stges E, F, nd G (see Figure 3), irrespective of growth phse nd other investigted fctors. Being tht spontneous eruption of mxillry cnines nd mndibulr second molr mturtion re prts of the sme dentl mturtion process, correltion between them ws expected. However, whether the eruption of the former my be predicted by the mturtion of the ltter with stisfctory relibility, nd whether other fctors my influence this prediction, hs still not been reported. Subjects included herein were seeking orthodontic tretment; therefore, greter prevlence of mlocclusion in the present smple ws seen compred with similr group in the generl popultion. 15 In prticulr, generl tendency towrd hyperdivergent skeletl clss II ws encountered (Tble 1). The overll prevlence of subjects t the prepubertl growth phse seen herein (52.8%) ws similr, though lower, thn tht reported previously (56.6%). 5 According to previous results, 4,5 no subject herein showed spontneous eruption of the mxillry cnine t the postpubertl growth phse. In the present study, the correltion between the spontneous mxillry cnine eruption nd mturtion Tble 3. Ordered Multiple Regression Model for the Assocition of Ech Explntory Vrible With the Second Molr Mturtionl Stge Prmeter b (SE) 95% CI Significnce Age (0.192) P,.01 Sex (femles) (0.415) NS Growth phse (prepubertl) (0.428) NS SN/MP ngle (0.034) NS ANB ngle (0.101) NS Stge H is the reference ctegory for the second molr mturtion; n b (SE) indictes men bet coefficient (stndrd error of the men); 95% CI, 95% confidence intervl; NS, not sttisticlly significntly different.

5 582 PERINETTI, CALLOVI, SALGARELLO, BIASOTTO, CONTARDO Figure 3. The permnent mxillry cnine during the finl phse of eruption in three subjects, long with the mturtionl stges of the mndibulr second molr. In these subjects, the finl phse of eruption of the mxillry cnine is ssocited with mturtionl stges E (ptient 106), F (ptient 101), nd G (ptient 105). of the mndibulr second molr ws not influenced by sex, growth phse, or dentofcil growth fetures. On the contrry, previous study 5 reported n erlier eruption for hyperdivergent subjects but only when the mxillry cnine eruption is ttined t prepubertl growth phse. This finding is consistent with the evidence tht dentl mturtion would occur erlier in subjects with n extreme verticl fce type. 11 However, previous studies 5,11 did not djust correltions by the use of multiple regression models. Regrding the sgittl skeletl fcil fetures, the present evidence is in greement with previous findings. 5 Nevertheless, potentil effects by other fctors, such s genetic or hormonl fetures, my be responsible for the intersubject vrition seen in the timing of the spontneous eruption of the mxillry cnines. In comprison with the growth phse, mturtion of the mndibulr second molr my thus be considered more strictly relted to the spontneous eruption of the mxillry cnine. This my be expected s these re two events of the sme overll mturtion of the dentl rches. Therefore, s reported for the ttinment of the postpubertl growth phse, 5 cnine impction cn be suspected when not erupted fter the complete root formtion of the mndibulr second molr. In this cse, n implementtion of the dignosis would be deemed. Consistently for both femles nd mles, intervls of 18 months were seen s the time required for mndibulr second molr to mture from stge E to F nd from stge F to G (Figure 2). This informtion on the timing of mturtion of the mndibulr second molr my be helpful when mnging interceptive tretments for mxillry displced cnines. Indeed, knowledge of the timing t which the mxillry cnines cn still undergo spontneous eruption is useful for determining the expected ppernce in the orl cvity. On the contrry, if cnine hs not erupted by the ttinment of mndibulr second molr stge H, even fter n interceptive tretment, surgicl pproch my be considered, especilly if other dignostic fetures of cnine impction re noted. 1 Considering tht ll subjects undergo spontneous eruption of the mxillry cnine when the mndibulr second molr mturtion is between stges E nd G, informtion regrding timing of eruption my be vilble in ll the subjects, irrespective of sex, growth phse, nd verticl nd sgittl skeletl fcil fetures. Even though the CVM method hs been shown to be relible indictor of the timing of cnine eruption, this nlysis requires lterl hed film, which is vilble s pretretment record. However, in severl instnces, optiml tretment timing is delyed until fter the dignosis, mking lter reevlution of the growth phse necessry. Moreover, the cervicl vertebre might be prtilly covered by the protection

6 CANINE ERUPTION AND SECOND MOLAR MATURITY 583 collr, which would be necessry to reduce rdition exposure. 16 On the other hnd, rdiogrphic recording of the hnd nd wrist requires dditionl x-ry exposure nd dedicted x-ry mchine. Importntly, for both methods, re-execution of recordings to reevlute growth phses only is not indicted ccording to some recent guidelines. 17 In this view, the use of the mndibulr second molr mturtion to predict the timing for eruption of the mxillry cnines offers the dvntge of esy interprettion, nd it does not require dditionl x-ry exposure to the ptient when dentl pnormic record is vilble. The rdiogrphic recording of the region of the mndibulr second molr lso voids doubling or superimposition of the recorded structures with ntomic fetures of the distl root tht re clerly visible. Moreover, the sme pnormic rdiogrph my be used to retrieve other relevnt informtion regrding the identifiction of potentil displced/impcted cnine. 18 Finlly, if needed, n introrl peripicl rdiogrphic record of the mndibulr second molr my be tken during follow-up visits with miniml irrdition to the ptients. CONCLUSIONS N Spontneous eruption of the mxillry cnine occurs between stges E nd G of the mndibulr second molr, irrespective of sex, growth phse, nd fcil fetures. N The mturtionl stge of the mndibulr second molr my be relible indictor for the timing of spontneous eruption of the mxillry cnine. REFERENCES 1. Bedoy MM, Prk JH. A review of the dignosis nd mngement of impcted mxillry cnines. J Am Dent Assoc. 2009;140: Bccetti T, Leonrdi M, Armi P. A rndomized clinicl study of two interceptive pproches to pltlly displced cnines. Eur J Orthod. 2008;30: Bjork A, Helm S. Prediction of the ge of mximum puberl growth in body height. Angle Orthod. 1967;37: Hägg U, Trnger J. Mturtion indictors nd the pubertl growth spurt. Am J Orthod. 1982;82: Bccetti T, Frnchi L, De Lis S, Giuntini V. Eruption of the mxillry cnines in reltion to skeletl mturity. Am J Orthod Dentofcil Orthop. 2008;133: Perinetti G, Contrdo L, Gbrieli P, Bccetti T, Di Lenrd R. Dignostic performnce of dentl mturity for identifiction of skeletl mturtion phse. Eur J Orthod. 2012;34: Perinetti G, Di Lenrd R, Contrdo L. Dignostic performnce of combined cnine nd second molr mturity for identifiction of growth phse. Prog Orthod In press. 8. Ericson S, Kurol J. Erly tretment of pltlly erupting mxillry cnines by extrction of the primry cnines. Eur J Orthod. 1988;10: Bccetti T, Frnchi L, McNmr JAJ. The cervicl vertebrl mturtion (CVM) method for the ssessment of optiml tretment timing in dentofcil orthopedics. Semin Orthod. 2005;11: Demirjin A, Goldstein H, Tnner JM. A new system of dentl ge ssessment. Hum Biol. 1973;45: Jnson GR, Mrtins DR, Tvno O, Dinesi EA. Dentl mturtion in subjects with extreme verticl fcil types. Eur J Orthod. 1998;20: Brenner H, Kliebsch U. Dependence of weighted kpp coefficients on the number of ctegories. Epidemiology. 1996;7: Lndis JR, Koch GG. The mesurement of observer greement for ctegoricl dt. Biometrics. 1977;33: Springte SD. The effect of smple size nd bis on the relibility of estimtes of error: comprtive study of Dhlberg s formul. Eur J Orthod. 2012;34: Perinetti G, Cordell C, Pellegrini F, Esposito P. The prevlence of mlocclusl trits nd their correltions in mixed dentition children: results from the Itlin OHSAR Survey. Orl Helth Prev Dent. 2008;6: Ptcs R, Signorelli L, Peltomki T, Schtzle M. Is the use of the cervicl vertebre mturtion method justified to determine skeletl ge? A comprison of rdition dose of two strtegies for skeletl ge estimtion. Eur J Orthod Jul 30. [Epub hed of print]. 17. Iscson KG, Thom AR, Horner K, Whites E. Orthodontic Rdiogrphs Guidelines for the Use of Rdiogrphs in Clinicl Orthodontics. 3rd ed. London, UK: British Orthodontic Society; Linduer SJ, Rubenstein LK, Hng WM, Andersen WC, Iscson RJ. Cnine impction identified erly with pnormic rdiogrphs. J Am Dent Assoc. 1992;123:91 92,