Association between 3D palatal morphology and upper arch dimensions in buccally displaced maxillary canines early in mixed dentition

Association between 3D palatal morphology and upper arch dimensions in buccally displaced... Summary Objectives To evaluate the association between maxillary dental arch transverse dimensions, palatal depths, palatal area and volume with buccally displaced canine (BDC) in mixed dentition subjects when compared to non-BDC subjects using laser scanner 3D technology. Materials and methods Sixty Caucasian subjects, 8–11 years of age (mean, 9.26 ± 1.48 years), were included. In each group (BDC and non-BDC) 30 children were matched. Digital dental casts were obtained using a 3 Shape D700 laser scanner. Intercanine and intermolar widths (cusp and gingival levels), anterior and posterior palatal depth (cusp level), palatal surface area and volume were measured. An independent sample Student’s t-test and an ANOVA were undertaken with significance level set as P < 0.05. Results Intercanine widths at the cusp (1.76 mm; P = 0.020) and the gingival level (1.6 mm; P = 0.006), palatal area (133 mm2; P = 0.021) and volume (790 mm3; P = 0.046) were significantly lower in the BDC compared to the control group. Limitations A smaller part of the subjects was in late mixed dentition phase. To overcome this limitation a matched control group was used. Some subjects did not have some teeth because of the transition phase which might have had an influence on the dental measurements. However, these subjects were not excluded to avoid introducing a bias. Conclusions 3D evaluation of the maxillary arch and palate highlighted significant differences between BDC and non-BDC mixed dentition subjects. Maxillary dental arch dimensions and palate morphology may allow early identification and prevention of maxillary canine impaction. Introduction Tooth impaction can be defined as the untimely infraosseous position of the tooth after its expected eruption time. For the maxillary canines such scenario would occur beyond 14 years of age, whereas before this age the anomalous infraosseous position of the canine can be defined as displacement (1). Displaced maxillary canine (DMC) can be palatally or buccally positioned (2). In European population, the average prevalence of buccally displaced canine (BDC) is 3.1 per cent with a male-to-female ratio of 1:1 (3), while the prevalence of palatally displaced canine (PDC) is 2.4 per cent with a male-to-female ratio of 1:3 (4). Numerous etiological factors are involved in BDC and PDC although their exact influence is not completely clear (1, 5, 6). What seems to be known is that BDC are mainly associated with lack of space in the arch (crowding) (5, 6), while PDC with hypoplastic/missing lateral incisors (guidance theory) or with aplasia of molars and hypodontia (genetic theory) (1). Other reported causes of DMC are disturbances in tooth eruption sequence, trauma, retention of primary canine, premature root closure, rotation of tooth buds, as well as localized pathological lesions such as cysts and odontomas (1). The relationship between BDC and the morphology of the upper dental arch when measuring transverse widths has been already investigated using conventional two-dimensional dental cast analysis (3, 7, 8). Mucedero et al. (3) showed a significant reduction of the maxillary intercanine width in BDC subjects when compared to the control group. However, no significant difference between the two groups for maxillary intermolar width was found. Also McConnell et al. (7) showed the same outcomes although in DMC subjects. Conversely, Larsen et al. (8) reported that the maxillary intermolar width was significantly enlarged transversally in subjects with DMC. Two-dimensional (2D) methods used in the previous studies, although reliable, are time-consuming and insufficient to provide reliable volumetric data (9–11). To the best of our knowledge, there are no three-dimensional (3D) studies focusing on the maxillary morphology (palatal area and volume) and its correlation with BDC. Understanding the association between BDC and maxillary morphology could be useful for early identification and prevention of maxillary canine impaction in those patients with maxillary deficiency, as they seem to be more likely to have an impacted canine (3). In the past only linear dental arch dimensions have been explored. As the complexity of palatal morphology can only be properly explored with 3D volumetric measurements, we were interested in assessing that unexplored area in BDC. So the purpose of this study was to evaluate the association between the maxillary dental arch transverse dimensions, palatal depths, palatal area and volume and the presence of BDC using laser scanner 3D technology. Materials and methods Approval for this comparative cross-sectional study was granted by the Ethics Committee of the University of Campania “Luigi Vanvitelli” (n. 497, 2017). A signed informed consent from the subjects’ parents was obtained. Material and study design A total of 60 Caucasian subjects referred for an initial visit at the Program of Orthodontics of University of Campania “Luigi Vanvitelli”, Naples, Italy, from January 2016 to January 2017, were included. The BDC group consisted of a sample of 30 subjects (22 girls and 8 boys; aged 9.26 ± 1.48 years) (Table1), all in the mixed dentition phase with cervical vertebral maturation (CVM) less than 4 (12). Initial dental casts of all subjects were used to verify the absence of erupted canines in the upper arch and the presence of canine bulges (1). Radiographic material (panoramic X-ray, lateral caphalograms) was used to confirm the presence of BDC according to the sectors proposed by Lindauer et al. (13) and α angle of Power and Short (14) (sectors II, III, IV and α angle > 31 degree) and to specify the intraosseous location (palatal or buccal) of the canines (15) (Table 2). Subjects with craniofacial malformations (including cleft lip or palate), history of dental trauma, oral neoformations and other oral cavity pathologies, or previous or concomitant orthodontic treatment were excluded. The control group consisted of 30 untreated non-BDC subjects. These children were matched for sex, age, dentition phase and type of malocclusion. The same inclusion and exclusion criteria were applied to the control group, except for the presence of BDC (the subjects present both canines in sectors I and α angle <31 degree). Table 1. Characteristics of the samples. Group Total Male Female Age N n n µ ± SD Total 60 16 44 9.13 ± 1.60 CTR 30 8 22 9.04 ± 1.66 BDC 30 8 22 9.26 ± 1.48 Group Total Male Female Age N n n µ ± SD Total 60 16 44 9.13 ± 1.60 CTR 30 8 22 9.04 ± 1.66 BDC 30 8 22 9.26 ± 1.48 CTR, control group; BDC, buccal displaced canine group; n = subjects. View Large Table 1. Characteristics of the samples. Group Total Male Female Age N n n µ ± SD Total 60 16 44 9.13 ± 1.60 CTR 30 8 22 9.04 ± 1.66 BDC 30 8 22 9.26 ± 1.48 Group Total Male Female Age N n n µ ± SD Total 60 16 44 9.13 ± 1.60 CTR 30 8 22 9.04 ± 1.66 BDC 30 8 22 9.26 ± 1.48 CTR, control group; BDC, buccal displaced canine group; n = subjects. View Large Table 2. Unilateral and bilateral distribution of BDC (buccal displaced canine), based on Lindaeur et al. classification. Unilateral n* Bilateral n* Sectors II III IV Total II, II II, III III, III IV, IV Total BDC 10 9 2 21 5 2 1 1 9 Unilateral n* Bilateral n* Sectors II III IV Total II, II II, III III, III IV, IV Total BDC 10 9 2 21 5 2 1 1 9 *n = subjects. View Large Table 2. Unilateral and bilateral distribution of BDC (buccal displaced canine), based on Lindaeur et al. classification. Unilateral n* Bilateral n* Sectors II III IV Total II, II II, III III, III IV, IV Total BDC 10 9 2 21 5 2 1 1 9 Unilateral n* Bilateral n* Sectors II III IV Total II, II II, III III, III IV, IV Total BDC 10 9 2 21 5 2 1 1 9 *n = subjects. View Large Three-dimensional evaluation of upper arch and palate morphology The study casts were scanned using a 3D scanner (3shape D700) with a reported manufacturing accuracy of less than 20 microns (www.3shape.com). The 3D data were imported to a reverse modelling software package, Geomagic Studio (3D Systems, Inc) (16). Each study cast scan was manually preprocessed to remove unwanted data such as some degree of imaging noise around the surface boundary of the model to allow for adequate imaging analysis. All 3D scanners are based on the principle known as ‘triangulation’. The light source projects all lines onto the surface of the object and the camera acquires images of the lines. Based on the known angle and distance between camera and light source the 3D position where the projected light is reflected can be calculated using trigonometry. For this reason, the measurements are not influenced by the orientation of the cast inside the machine. Then intermolar and intercanine transverse widths at the cusps and gingival level (Figure 1), anterior and posterior palatal depths at the cusp level (Figure 2) as well as palatal surface area (Figure 3) and volume (Figure 4) were measured. The anterior and posterior depth of the palatal vault was defined as the vertical distance from the contact line between the cusp of the right and left canine and mesiopalatal cusp tips of the right and left first molars to the palatal vault, respectively. The palatal surface area and the palatal volume were calculated using a customized method to create the median sagittal, distal and gingival planes as boundaries of the palate (Figure 5a–d). The distal plane was created through two points at the distal of the first upper permanent molars. The gingival plane was created by intersecting the distal and median sagittal planes through the centre of incisive papilla which is considered a stable point structure (17). That is the only plane perpendicular both to the sagittal and the distal plane passing though the centre of incisive papilla. All planes were perpendicular to each other. Figure 1. View largeDownload slide Assessment of the upper arch on 3D digitized cast. Intermolar and intercanine widths assessed at the cusp (red lines) and gingival (blue lines) level on 3D maxillary digitized model. Figure 1. View largeDownload slide Assessment of the upper arch on 3D digitized cast. Intermolar and intercanine widths assessed at the cusp (red lines) and gingival (blue lines) level on 3D maxillary digitized model. Figure 2. View largeDownload slide Anterior and posterior palatal depths at cusp level. Figure 2. View largeDownload slide Anterior and posterior palatal depths at cusp level. Figure 3. View largeDownload slide Calculation of the palatal surface area on 3D digitized cast. Figure 3. View largeDownload slide Calculation of the palatal surface area on 3D digitized cast. Figure 4. View largeDownload slide Calculation of the palatal volume on 3D digitized cast. Figure 4. View largeDownload slide Calculation of the palatal volume on 3D digitized cast. Figure 5. View largeDownload slide The palatal volume (d) was delimited using a median sagittal plane (a), a distal plane (b) and a gingival plane (c). Figure 5. View largeDownload slide The palatal volume (d) was delimited using a median sagittal plane (a), a distal plane (b) and a gingival plane (c). Statistical analysis All measurements were carried out by the same observer, three times at weekly intervals to calculate the intra-operator error assessment. Furthermore, all measurements were carried out by another observer, one time to calculate the inter-operator error assessment. The mean value, standard deviation (SD) and intra-class and inter-class correlation coefficients (ICC end Cohen’s kappa) were calculated to evaluate the reliability of the method. Minitab Statistical Software (Minitab, Inc., State College, Pennsylvania, USA) was used for statistical analysis. Data were tested for normal distribution according to Levene’s test. Analysis of variance (ANOVA) test considered the effect of age and sex and their interactions on the parameters. An independent samples Student’s t-test was used to calculate the statistical differences between the BDC and the non-BDC groups for each measurement. The mean values, standard deviations and percentages were calculated to determine statistically significant differences. The results were considered to be significant at values P < 0.05. Results A post hoc analysis of the obtained power for each variable with statistical significant differences showed a power of 97.5 and 99.5 per cent for intercanine measurements at cusp and gingival level, respectively, of 90.3 per cent for the area difference and of 73.9 per cent for the volumetric difference. The error of method was not clinically relevant. For palatal surface area ICC was 0.983 [95% confidence interval (CI) = 0.970–0.991] with measurement error of 1.08% (95% CI = 0.55–1.62%). For palatal volume, the ICC was 0.987 (95% CI = 0.978–0.994) with measurement error of 0.81% (95% CI = 0.41–1.21). For palatal surface area inter-rater Cohen’s kappa coefficient was 0.874 (95% CI = 0.830–0.918). For palatal volume inter-rater Cohen’s kappa coefficient was 0.855 (95% CI = 0.804–0.906). In summary, values showed a good level of accuracy for all the variables. The error of method was also not clinically relevant. For palatal surface area ICC was 0.983 (95% CI = 0.970–0.991). For palatal volume the ICC was 0.987 (95% CI = 0.978–0.994). The mean values and standard deviations of the intercanine and intermolar widths, palatal depths, palatal surface areas and volumes for each group and P-values for group comparisons were reported in Table 3. Data distribution was considered normal for palatal surface area (P = 0.541) and volume (P = 0.097). Palatal area (133 mm2; P = 0.021) and volume (790 mm3; P = 0.046) were significantly smaller for BDC with a reduction of 12% and 18%, respectively. Intercanine and intermolar widths were also normally distributed at the cusp (P = 0.893; P = 0.943) and gingival level (P = 0.801; P = 0.511), respectively. Intercanine widths were significantly smaller at the cusp (1.76 mm; P = 0.020) and gingival level (1.6 mm; P = 0.006) whereas intermolar widths were reduced, but not significantly, both at the cusp (P = 0.113) and at the gingival level (P = 0.406). Table 3. Upper arch and palate parameters for BDC and non-BDC groups and respective group comparisons. Parameter BDC group non-BDC group P value* Mean SD Mean SD Intercanine cusp (mm) 30.81 2.83 32.57 2.51 0.020 Intercanine ging (mm) 23.77 2.01 25.37 1.94 0.006 Intermolar cusp (mm) 47.42 3.06 48.69 2.83 0.113 Intermolar ging (mm) 31.51 3.21 32.15 2.41 0.406 Ant palatal depth (mm) 6.66 1.37 5.92 1.77 0.104 Post palatal depth (mm) 14.93 1.58 15.48 1.97 0.255 Area (mm2) 1076 193 1209 2.24 0.021 Volume (mm3) 4475 1176 5265 1664 0.046 Parameter BDC group non-BDC group P value* Mean SD Mean SD Intercanine cusp (mm) 30.81 2.83 32.57 2.51 0.020 Intercanine ging (mm) 23.77 2.01 25.37 1.94 0.006 Intermolar cusp (mm) 47.42 3.06 48.69 2.83 0.113 Intermolar ging (mm) 31.51 3.21 32.15 2.41 0.406 Ant palatal depth (mm) 6.66 1.37 5.92 1.77 0.104 Post palatal depth (mm) 14.93 1.58 15.48 1.97 0.255 Area (mm2) 1076 193 1209 2.24 0.021 Volume (mm3) 4475 1176 5265 1664 0.046 *Independent t-test was performed for comparison of the mean differences between the two groups. SD, standard deviation. View Large Table 3. Upper arch and palate parameters for BDC and non-BDC groups and respective group comparisons. Parameter BDC group non-BDC group P value* Mean SD Mean SD Intercanine cusp (mm) 30.81 2.83 32.57 2.51 0.020 Intercanine ging (mm) 23.77 2.01 25.37 1.94 0.006 Intermolar cusp (mm) 47.42 3.06 48.69 2.83 0.113 Intermolar ging (mm) 31.51 3.21 32.15 2.41 0.406 Ant palatal depth (mm) 6.66 1.37 5.92 1.77 0.104 Post palatal depth (mm) 14.93 1.58 15.48 1.97 0.255 Area (mm2) 1076 193 1209 2.24 0.021 Volume (mm3) 4475 1176 5265 1664 0.046 Parameter BDC group non-BDC group P value* Mean SD Mean SD Intercanine cusp (mm) 30.81 2.83 32.57 2.51 0.020 Intercanine ging (mm) 23.77 2.01 25.37 1.94 0.006 Intermolar cusp (mm) 47.42 3.06 48.69 2.83 0.113 Intermolar ging (mm) 31.51 3.21 32.15 2.41 0.406 Ant palatal depth (mm) 6.66 1.37 5.92 1.77 0.104 Post palatal depth (mm) 14.93 1.58 15.48 1.97 0.255 Area (mm2) 1076 193 1209 2.24 0.021 Volume (mm3) 4475 1176 5265 1664 0.046 *Independent t-test was performed for comparison of the mean differences between the two groups. SD, standard deviation. View Large The distributions of anterior and posterior palatal depths were both considered normal (P = 0.702; P = 0.373). Anterior palatal depth was increased, but not significantly (P = 0.104), whereas posterior palatal depth was reduced but also this one not significantly (P = 0.255). Discussion The aim of the present study was to evaluate the association between the maxillary dental arch transverse dimensions, palatal depths, palatal area and volume and the presence of BDC using laser scanner 3D technology to better understand the association between BDC and maxillary morphology (area and volume) for early identification and prevention of future canine impaction. The anatomical characteristics of the upper arch and palate in BDC subjects have been previously evaluated by measuring only the intercanine and intermolar widths (linear distances) (3, 7, 8). In this study, we evaluated in BDC subjects, not only the upper arch widths and depths, but also the palatal surface area and volume because these two 3D measurements have been previously reported as reliable indicators of palatal and maxillary arch growth (18). The question is whether buccal displacement of the canines is the result of the deviated growth of the maxillary complex or whether deviation in eruption is independent from morphology of the maxillary complex (8). Our results suggested that all these measurements in BDC subjects were significantly smaller compared to non-BDC subjects, implying that untreated BDC subjects in the mixed dentition showed a significantly different upper arch morphology, with a higher degree of constriction. Similarly to previous reports (3, 7), the results of our study reinforce that BDC is associated with decreased intercanine widths both at cusp and gingival levels. However, in the mixed dentition phase, no significant reduction of the intermolar widths was identified. Conversely Larsen et al. (8) in a group of DMC patients reported that the posterior transverse dimensions were significantly greater. Such results may be attributed to the heterogeneous sample of BDC and PDC. In fact, other authors (19) also reported greater posterior transverse dimensions in PDC compared with their control. To better describe the shape of the palatal vault, we also evaluated the anterior and posterior palatal depths at cusp level. The corresponding values differ between BDC and non-BDC group, but not significantly. In association with statistically reduced intercanine width, an increased anterior palatal depth could signifies that the palatal vault in BDC group is narrower and deeper in its anterior portion compared to non-BDC group. No previous studies, reported data on these parameters in BDC subjects, so a direct comparison was not possible. As the assessment of upper arch morphology based on interdental measurements does not fully consider the 3D morphological characteristics and could be biased due to axial inclination of the first molars and/or the alveolar bridge, palatal surface area and volume were used to better describe the upper arch and palate morphology using 3D laser technology as previously suggested (18). Both the palatal surface area and volume were significantly smaller in BDC than in non-BDC group. A direct comparison with other studies was not possible because our study was the first attempt to perform a 3D evaluation of palatal area and volume in untreated BDC subjects compared with untreated healthy subjects in mixed dentition phase. Therefore, we probably added a missing piece in the puzzle of the upper arch and palate morphology in BDC individuals during the development of the dentition. In fact, our results suggested that in the diagnosis of BDC cases transverse widths as well as palatal area and palatal volume must be taken into account. Upper arch constriction in BDC subjects could contribute to the aetiology of buccal canine impaction (3). In that light a 3D analysis of the upper arch can improve diagnosis and treatment of cases with BDC (18). Several methods of interceptive treatment of DMC have been described in the literature such as extraction of deciduous canine (single extraction approach), concomitant deciduous canine and first molar extractions (double extraction approach) (14, 20–22), use of maxillary expansion, transpalatal arch or headgear therapy in combination with the single or double extraction approach (22–25), often focusing on PDC (26). Transverse dimensions, palatal area and volume can be finally considered as risk indicators for developing a buccal canine impaction. Thus, according to the result of the present study, expansion, with an emphasis in the anterior reduced section of the palate, should be also considered for BDC beneficial, to increase palatal area and volume and allow normal canine eruption preventing impaction. Limitations The sample included patients both in the early and late mixed dentition phase. To overcame this potential confounder a matched control group was used. The sample included subjects who did not have some teeth, such as deciduous canines or first molars, elements required for both linear and volumetric measurement with Geomagic software, and therefore some measurements were missing. Specifically seven subjects, one in BDC group and six in the control group did not have the deciduous canine because of the transition phase, while four subjects, two in the BDC group and two in the control group did not have the first molar since they were still erupting. However, these subjects have not been excluded to avoid introducing a bias. Only those variables that were not been able to be measured were excluded from the analysis. Conclusions Subjects with BDC have a significantly reduced intercanine upper arch widths with a narrower shape of the anterior portion, while intermolar widths and depths are similar to those measured in matched subjects without BDC. Moreover also significantly smaller palatal surface area and volume were seen in untreated BDC subjects. Conflict of Interest None to declare. References 1. Litsas , G. and Acar , A . ( 2011 ) A review of early displaced maxillary canines: etiology, diagnosis and interceptive treatment . The Open Dentistry Journal , 5 , 39 – 47 . Google Scholar CrossRef Search ADS PubMed 2. Schindel , R.H. and Duffy , S.L . ( 2007 ) Maxillary transverse discrepancies and potentially impacted maxillary canines in mixed-dentition patients . The Angle Orthodontist , 77 , 430 – 435 . Google Scholar CrossRef Search ADS PubMed 3. Mucedero , M. , Ricchiuti , M.R. , Cozza , P. and Baccetti , T . ( 2013 ) Prevalence rate and dentoskeletal features associated with buccally displaced maxillary canines . European Journal of Orthodontics , 35 , 305 – 309 . Google Scholar CrossRef Search ADS PubMed 4. Sacerdoti , R. and Baccetti , T . ( 2004 ) Dentoskeletal features associated with unilateral or bilateral palatal displacement of maxillary canines . The Angle Orthodontist , 74 , 725 – 732 . Google Scholar PubMed 5. Chaushu , S. , Sharabi , S. and Becker , A . ( 2003 ) Tooth size in dentitions with buccal canine ectopia . European Journal of Orthodontics , 25 , 485 – 491 . Google Scholar CrossRef Search ADS PubMed 6. Chaushu , S. , Bongart , M. , Aksoy , A. , Ben-Bassat , Y. and Becker , A . ( 2009 ) Buccal ectopia of maxillary canines with no crowding . American Journal of Orthodontics and Dentofacial Orthopedics , 136 , 218 – 223 . Google Scholar CrossRef Search ADS PubMed 7. McConnell , T.L. , Hoffman , D.L. , Forbes , D.P. , Janzen , E.K. and Weintraub , N.H . ( 1996 ) Maxillary canine impaction in patients with transverse maxillary deficiency . ASDC Journal of Dentistry for Children , 63 , 190 – 195 . Google Scholar PubMed 8. Larsen , H.J. , Sørensen , H.B. , Artmann , L. , Christensen , I.J. and Kjaer , I . ( 2010 ) Sagittal, vertical and transversal dimensions of the maxillary complex in patients with ectopic maxillary canines . Orthodontics & Craniofacial Research , 13 , 34 – 39 . Google Scholar CrossRef Search ADS PubMed 9. Primožič , J. , Perinetti , G. , Richmond , S. and Ovsenik , M . ( 2012 ) Three-dimensional longitudinal evaluation of palatal vault changes in growing subjects . The Angle Orthodontist , 82 , 632 – 636 . Google Scholar CrossRef Search ADS PubMed 10. Primožic , J. , Baccetti , T. , Franchi , L. , Richmond , S. , Farčnik , F. and Ovsenik , M . ( 2013 ) Three-dimensional assessment of palatal change in a controlled study of unilateral posterior crossbite correction in the primary dentition . European Journal of Orthodontics , 35 , 199 – 204 . Google Scholar CrossRef Search ADS PubMed 11. Primozic , J. , Ovsenik , M. , Richmond , S. , Kau , C.H. and Zhurov , A . ( 2009 ) Early crossbite correction: a three-dimensional evaluation . European Journal of Orthodontics , 31 , 352 – 356 . Google Scholar CrossRef Search ADS PubMed 12. Baccetti , T. , Franchi , L. and McNamara , J.A. , Jr . ( 2005 ) The cervical vertebral maturation (CVM) method for the assessment of optimal treatment timing in dentofacial orthopedics . Seminars in Orthodontics , 11 , 119 – 129 . Google Scholar CrossRef Search ADS 13. Lindauer , S.J. , Rubenstein , L.K. , Hang , W.M. , Andersen , W.C. and Isaacson , R.J . ( 1992 ) Canine impaction identified early with panoramic radiographs . Journal of the American Dental Association (1939) , 123 , 91 – 92, 95 . Google Scholar CrossRef Search ADS PubMed 14. Power , S.M. and Short , M.B . ( 1993 ) An investigation into the response of palatally displaced canines to the removal of deciduous canines and an assessment of factors contributing to favourable eruption . British Journal of Orthodontics , 20 , 215 – 223 . Google Scholar CrossRef Search ADS PubMed 15. Maverna , R. and Gracco , A . ( 2007 ) Different diagnostic tools for the localization of impacted maxillary canines: clinical considerations . Progress in Orthodontics , 8 , 28 – 44 . Google Scholar PubMed 16. Martorelli , M. , Maietta , S. , Gloria , A. , De Santis , R. , Pei , E. and Lanzotti , A . ( 2016 ) Design and analysis of 3D customized models of a human mandible . Procedia CIRP , 49 , 199 – 202 . Google Scholar CrossRef Search ADS 17. Shah , M. , Verma , A.K. and Chaturvedi , S . ( 2014 ) A comparative study to evaluate the vertical position of maxillary central incisor and canine in relation to incisive papilla line . Journal of Forensic Dental Sciences , 6 , 92 – 96 . Google Scholar CrossRef Search ADS PubMed 18. Generali , C. , Primozic , J. , Richmond , S. , Bizzarro , M. , Flores-Mir , C. , Ovsenik , M. and Perillo , L . ( 2017 ) Three-dimensional evaluation of the maxillary arch and palate in unilateral cleft lip and palate subjects using digital dental casts . European Journal of Orthodontics , 39 , 641 – 645 . Google Scholar CrossRef Search ADS PubMed 19. Al-Nimri , K. and Gharaibeh , T . ( 2005 ) Space conditions and dental and occlusal features in patients with palatally impacted maxillary canines: an aetiological study . European Journal of Orthodontics , 27 , 461 – 465 . Google Scholar CrossRef Search ADS PubMed 20. Williams , B.H . ( 1981 ) Diagnosis and prevention of maxillary cuspid impaction . The Angle Orthodontist , 51 , 30 – 40 . Google Scholar PubMed 21. Ericson , S. and Kurol , J . ( 1988 ) Early treatment of palatally erupting maxillary canines by extraction of the primary canines . European Journal of Orthodontics , 10 , 283 – 295 . Google Scholar CrossRef Search ADS PubMed 22. Alessandri Bonetti , G. , Incerti Parenti , S. , Zanarini , M. and Marini , I . ( 2010 ) Double vs single primary teeth extraction approach as prevention of permanent maxillary canines ectopic eruption . Pediatric Dentistry , 32 , 407 – 412 . Google Scholar PubMed 23. Leonardi , M. , Armi , P. , Franchi , L. and Baccetti , T . ( 2004 ) Two interceptive approaches to palatally displaced canines: a prospective longitudinal study . The Angle Orthodontist , 74 , 581 – 586 . Google Scholar PubMed 24. Baccetti , T. , Leonardi , M. and Armi , P . ( 2008 ) A randomized clinical study of two interceptive approaches to palatally displaced canines . European Journal of Orthodontics , 30 , 381 – 385 . Google Scholar CrossRef Search ADS PubMed 25. Baccetti , T. , Mucedero , M. , Leonardi , M. and Cozza , P . ( 2009 ) Interceptive treatment of palatal impaction of maxillary canines with rapid maxillary expansion: a randomized clinical trial . American Journal of Orthodontics and Dentofacial Orthopedics , 136 , 657 – 661 . Google Scholar CrossRef Search ADS PubMed 26. Baccetti , T. , Sigler , L.M. and McNamara , J.A. , Jr . ( 2011 ) An RCT on treatment of palatally displaced canines with RME and/or a transpalatal arch . European Journal of Orthodontics , 33 , 601 – 607 . Google Scholar CrossRef Search ADS PubMed © The Author(s) 2018. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The European Journal of Orthodontics Oxford University Press

Association between 3D palatal morphology and upper arch dimensions in buccally displaced maxillary canines early in mixed dentition

Loading next page...
 
/lp/ou_press/association-between-3d-palatal-morphology-and-upper-arch-dimensions-in-9x0cpV1M6K
Publisher
Oxford University Press
Copyright
© The Author(s) 2018. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com
ISSN
0141-5387
eISSN
1460-2210
D.O.I.
10.1093/ejo/cjy023
Publisher site
See Article on Publisher Site

Abstract

Summary Objectives To evaluate the association between maxillary dental arch transverse dimensions, palatal depths, palatal area and volume with buccally displaced canine (BDC) in mixed dentition subjects when compared to non-BDC subjects using laser scanner 3D technology. Materials and methods Sixty Caucasian subjects, 8–11 years of age (mean, 9.26 ± 1.48 years), were included. In each group (BDC and non-BDC) 30 children were matched. Digital dental casts were obtained using a 3 Shape D700 laser scanner. Intercanine and intermolar widths (cusp and gingival levels), anterior and posterior palatal depth (cusp level), palatal surface area and volume were measured. An independent sample Student’s t-test and an ANOVA were undertaken with significance level set as P < 0.05. Results Intercanine widths at the cusp (1.76 mm; P = 0.020) and the gingival level (1.6 mm; P = 0.006), palatal area (133 mm2; P = 0.021) and volume (790 mm3; P = 0.046) were significantly lower in the BDC compared to the control group. Limitations A smaller part of the subjects was in late mixed dentition phase. To overcome this limitation a matched control group was used. Some subjects did not have some teeth because of the transition phase which might have had an influence on the dental measurements. However, these subjects were not excluded to avoid introducing a bias. Conclusions 3D evaluation of the maxillary arch and palate highlighted significant differences between BDC and non-BDC mixed dentition subjects. Maxillary dental arch dimensions and palate morphology may allow early identification and prevention of maxillary canine impaction. Introduction Tooth impaction can be defined as the untimely infraosseous position of the tooth after its expected eruption time. For the maxillary canines such scenario would occur beyond 14 years of age, whereas before this age the anomalous infraosseous position of the canine can be defined as displacement (1). Displaced maxillary canine (DMC) can be palatally or buccally positioned (2). In European population, the average prevalence of buccally displaced canine (BDC) is 3.1 per cent with a male-to-female ratio of 1:1 (3), while the prevalence of palatally displaced canine (PDC) is 2.4 per cent with a male-to-female ratio of 1:3 (4). Numerous etiological factors are involved in BDC and PDC although their exact influence is not completely clear (1, 5, 6). What seems to be known is that BDC are mainly associated with lack of space in the arch (crowding) (5, 6), while PDC with hypoplastic/missing lateral incisors (guidance theory) or with aplasia of molars and hypodontia (genetic theory) (1). Other reported causes of DMC are disturbances in tooth eruption sequence, trauma, retention of primary canine, premature root closure, rotation of tooth buds, as well as localized pathological lesions such as cysts and odontomas (1). The relationship between BDC and the morphology of the upper dental arch when measuring transverse widths has been already investigated using conventional two-dimensional dental cast analysis (3, 7, 8). Mucedero et al. (3) showed a significant reduction of the maxillary intercanine width in BDC subjects when compared to the control group. However, no significant difference between the two groups for maxillary intermolar width was found. Also McConnell et al. (7) showed the same outcomes although in DMC subjects. Conversely, Larsen et al. (8) reported that the maxillary intermolar width was significantly enlarged transversally in subjects with DMC. Two-dimensional (2D) methods used in the previous studies, although reliable, are time-consuming and insufficient to provide reliable volumetric data (9–11). To the best of our knowledge, there are no three-dimensional (3D) studies focusing on the maxillary morphology (palatal area and volume) and its correlation with BDC. Understanding the association between BDC and maxillary morphology could be useful for early identification and prevention of maxillary canine impaction in those patients with maxillary deficiency, as they seem to be more likely to have an impacted canine (3). In the past only linear dental arch dimensions have been explored. As the complexity of palatal morphology can only be properly explored with 3D volumetric measurements, we were interested in assessing that unexplored area in BDC. So the purpose of this study was to evaluate the association between the maxillary dental arch transverse dimensions, palatal depths, palatal area and volume and the presence of BDC using laser scanner 3D technology. Materials and methods Approval for this comparative cross-sectional study was granted by the Ethics Committee of the University of Campania “Luigi Vanvitelli” (n. 497, 2017). A signed informed consent from the subjects’ parents was obtained. Material and study design A total of 60 Caucasian subjects referred for an initial visit at the Program of Orthodontics of University of Campania “Luigi Vanvitelli”, Naples, Italy, from January 2016 to January 2017, were included. The BDC group consisted of a sample of 30 subjects (22 girls and 8 boys; aged 9.26 ± 1.48 years) (Table1), all in the mixed dentition phase with cervical vertebral maturation (CVM) less than 4 (12). Initial dental casts of all subjects were used to verify the absence of erupted canines in the upper arch and the presence of canine bulges (1). Radiographic material (panoramic X-ray, lateral caphalograms) was used to confirm the presence of BDC according to the sectors proposed by Lindauer et al. (13) and α angle of Power and Short (14) (sectors II, III, IV and α angle > 31 degree) and to specify the intraosseous location (palatal or buccal) of the canines (15) (Table 2). Subjects with craniofacial malformations (including cleft lip or palate), history of dental trauma, oral neoformations and other oral cavity pathologies, or previous or concomitant orthodontic treatment were excluded. The control group consisted of 30 untreated non-BDC subjects. These children were matched for sex, age, dentition phase and type of malocclusion. The same inclusion and exclusion criteria were applied to the control group, except for the presence of BDC (the subjects present both canines in sectors I and α angle <31 degree). Table 1. Characteristics of the samples. Group Total Male Female Age N n n µ ± SD Total 60 16 44 9.13 ± 1.60 CTR 30 8 22 9.04 ± 1.66 BDC 30 8 22 9.26 ± 1.48 Group Total Male Female Age N n n µ ± SD Total 60 16 44 9.13 ± 1.60 CTR 30 8 22 9.04 ± 1.66 BDC 30 8 22 9.26 ± 1.48 CTR, control group; BDC, buccal displaced canine group; n = subjects. View Large Table 1. Characteristics of the samples. Group Total Male Female Age N n n µ ± SD Total 60 16 44 9.13 ± 1.60 CTR 30 8 22 9.04 ± 1.66 BDC 30 8 22 9.26 ± 1.48 Group Total Male Female Age N n n µ ± SD Total 60 16 44 9.13 ± 1.60 CTR 30 8 22 9.04 ± 1.66 BDC 30 8 22 9.26 ± 1.48 CTR, control group; BDC, buccal displaced canine group; n = subjects. View Large Table 2. Unilateral and bilateral distribution of BDC (buccal displaced canine), based on Lindaeur et al. classification. Unilateral n* Bilateral n* Sectors II III IV Total II, II II, III III, III IV, IV Total BDC 10 9 2 21 5 2 1 1 9 Unilateral n* Bilateral n* Sectors II III IV Total II, II II, III III, III IV, IV Total BDC 10 9 2 21 5 2 1 1 9 *n = subjects. View Large Table 2. Unilateral and bilateral distribution of BDC (buccal displaced canine), based on Lindaeur et al. classification. Unilateral n* Bilateral n* Sectors II III IV Total II, II II, III III, III IV, IV Total BDC 10 9 2 21 5 2 1 1 9 Unilateral n* Bilateral n* Sectors II III IV Total II, II II, III III, III IV, IV Total BDC 10 9 2 21 5 2 1 1 9 *n = subjects. View Large Three-dimensional evaluation of upper arch and palate morphology The study casts were scanned using a 3D scanner (3shape D700) with a reported manufacturing accuracy of less than 20 microns (www.3shape.com). The 3D data were imported to a reverse modelling software package, Geomagic Studio (3D Systems, Inc) (16). Each study cast scan was manually preprocessed to remove unwanted data such as some degree of imaging noise around the surface boundary of the model to allow for adequate imaging analysis. All 3D scanners are based on the principle known as ‘triangulation’. The light source projects all lines onto the surface of the object and the camera acquires images of the lines. Based on the known angle and distance between camera and light source the 3D position where the projected light is reflected can be calculated using trigonometry. For this reason, the measurements are not influenced by the orientation of the cast inside the machine. Then intermolar and intercanine transverse widths at the cusps and gingival level (Figure 1), anterior and posterior palatal depths at the cusp level (Figure 2) as well as palatal surface area (Figure 3) and volume (Figure 4) were measured. The anterior and posterior depth of the palatal vault was defined as the vertical distance from the contact line between the cusp of the right and left canine and mesiopalatal cusp tips of the right and left first molars to the palatal vault, respectively. The palatal surface area and the palatal volume were calculated using a customized method to create the median sagittal, distal and gingival planes as boundaries of the palate (Figure 5a–d). The distal plane was created through two points at the distal of the first upper permanent molars. The gingival plane was created by intersecting the distal and median sagittal planes through the centre of incisive papilla which is considered a stable point structure (17). That is the only plane perpendicular both to the sagittal and the distal plane passing though the centre of incisive papilla. All planes were perpendicular to each other. Figure 1. View largeDownload slide Assessment of the upper arch on 3D digitized cast. Intermolar and intercanine widths assessed at the cusp (red lines) and gingival (blue lines) level on 3D maxillary digitized model. Figure 1. View largeDownload slide Assessment of the upper arch on 3D digitized cast. Intermolar and intercanine widths assessed at the cusp (red lines) and gingival (blue lines) level on 3D maxillary digitized model. Figure 2. View largeDownload slide Anterior and posterior palatal depths at cusp level. Figure 2. View largeDownload slide Anterior and posterior palatal depths at cusp level. Figure 3. View largeDownload slide Calculation of the palatal surface area on 3D digitized cast. Figure 3. View largeDownload slide Calculation of the palatal surface area on 3D digitized cast. Figure 4. View largeDownload slide Calculation of the palatal volume on 3D digitized cast. Figure 4. View largeDownload slide Calculation of the palatal volume on 3D digitized cast. Figure 5. View largeDownload slide The palatal volume (d) was delimited using a median sagittal plane (a), a distal plane (b) and a gingival plane (c). Figure 5. View largeDownload slide The palatal volume (d) was delimited using a median sagittal plane (a), a distal plane (b) and a gingival plane (c). Statistical analysis All measurements were carried out by the same observer, three times at weekly intervals to calculate the intra-operator error assessment. Furthermore, all measurements were carried out by another observer, one time to calculate the inter-operator error assessment. The mean value, standard deviation (SD) and intra-class and inter-class correlation coefficients (ICC end Cohen’s kappa) were calculated to evaluate the reliability of the method. Minitab Statistical Software (Minitab, Inc., State College, Pennsylvania, USA) was used for statistical analysis. Data were tested for normal distribution according to Levene’s test. Analysis of variance (ANOVA) test considered the effect of age and sex and their interactions on the parameters. An independent samples Student’s t-test was used to calculate the statistical differences between the BDC and the non-BDC groups for each measurement. The mean values, standard deviations and percentages were calculated to determine statistically significant differences. The results were considered to be significant at values P < 0.05. Results A post hoc analysis of the obtained power for each variable with statistical significant differences showed a power of 97.5 and 99.5 per cent for intercanine measurements at cusp and gingival level, respectively, of 90.3 per cent for the area difference and of 73.9 per cent for the volumetric difference. The error of method was not clinically relevant. For palatal surface area ICC was 0.983 [95% confidence interval (CI) = 0.970–0.991] with measurement error of 1.08% (95% CI = 0.55–1.62%). For palatal volume, the ICC was 0.987 (95% CI = 0.978–0.994) with measurement error of 0.81% (95% CI = 0.41–1.21). For palatal surface area inter-rater Cohen’s kappa coefficient was 0.874 (95% CI = 0.830–0.918). For palatal volume inter-rater Cohen’s kappa coefficient was 0.855 (95% CI = 0.804–0.906). In summary, values showed a good level of accuracy for all the variables. The error of method was also not clinically relevant. For palatal surface area ICC was 0.983 (95% CI = 0.970–0.991). For palatal volume the ICC was 0.987 (95% CI = 0.978–0.994). The mean values and standard deviations of the intercanine and intermolar widths, palatal depths, palatal surface areas and volumes for each group and P-values for group comparisons were reported in Table 3. Data distribution was considered normal for palatal surface area (P = 0.541) and volume (P = 0.097). Palatal area (133 mm2; P = 0.021) and volume (790 mm3; P = 0.046) were significantly smaller for BDC with a reduction of 12% and 18%, respectively. Intercanine and intermolar widths were also normally distributed at the cusp (P = 0.893; P = 0.943) and gingival level (P = 0.801; P = 0.511), respectively. Intercanine widths were significantly smaller at the cusp (1.76 mm; P = 0.020) and gingival level (1.6 mm; P = 0.006) whereas intermolar widths were reduced, but not significantly, both at the cusp (P = 0.113) and at the gingival level (P = 0.406). Table 3. Upper arch and palate parameters for BDC and non-BDC groups and respective group comparisons. Parameter BDC group non-BDC group P value* Mean SD Mean SD Intercanine cusp (mm) 30.81 2.83 32.57 2.51 0.020 Intercanine ging (mm) 23.77 2.01 25.37 1.94 0.006 Intermolar cusp (mm) 47.42 3.06 48.69 2.83 0.113 Intermolar ging (mm) 31.51 3.21 32.15 2.41 0.406 Ant palatal depth (mm) 6.66 1.37 5.92 1.77 0.104 Post palatal depth (mm) 14.93 1.58 15.48 1.97 0.255 Area (mm2) 1076 193 1209 2.24 0.021 Volume (mm3) 4475 1176 5265 1664 0.046 Parameter BDC group non-BDC group P value* Mean SD Mean SD Intercanine cusp (mm) 30.81 2.83 32.57 2.51 0.020 Intercanine ging (mm) 23.77 2.01 25.37 1.94 0.006 Intermolar cusp (mm) 47.42 3.06 48.69 2.83 0.113 Intermolar ging (mm) 31.51 3.21 32.15 2.41 0.406 Ant palatal depth (mm) 6.66 1.37 5.92 1.77 0.104 Post palatal depth (mm) 14.93 1.58 15.48 1.97 0.255 Area (mm2) 1076 193 1209 2.24 0.021 Volume (mm3) 4475 1176 5265 1664 0.046 *Independent t-test was performed for comparison of the mean differences between the two groups. SD, standard deviation. View Large Table 3. Upper arch and palate parameters for BDC and non-BDC groups and respective group comparisons. Parameter BDC group non-BDC group P value* Mean SD Mean SD Intercanine cusp (mm) 30.81 2.83 32.57 2.51 0.020 Intercanine ging (mm) 23.77 2.01 25.37 1.94 0.006 Intermolar cusp (mm) 47.42 3.06 48.69 2.83 0.113 Intermolar ging (mm) 31.51 3.21 32.15 2.41 0.406 Ant palatal depth (mm) 6.66 1.37 5.92 1.77 0.104 Post palatal depth (mm) 14.93 1.58 15.48 1.97 0.255 Area (mm2) 1076 193 1209 2.24 0.021 Volume (mm3) 4475 1176 5265 1664 0.046 Parameter BDC group non-BDC group P value* Mean SD Mean SD Intercanine cusp (mm) 30.81 2.83 32.57 2.51 0.020 Intercanine ging (mm) 23.77 2.01 25.37 1.94 0.006 Intermolar cusp (mm) 47.42 3.06 48.69 2.83 0.113 Intermolar ging (mm) 31.51 3.21 32.15 2.41 0.406 Ant palatal depth (mm) 6.66 1.37 5.92 1.77 0.104 Post palatal depth (mm) 14.93 1.58 15.48 1.97 0.255 Area (mm2) 1076 193 1209 2.24 0.021 Volume (mm3) 4475 1176 5265 1664 0.046 *Independent t-test was performed for comparison of the mean differences between the two groups. SD, standard deviation. View Large The distributions of anterior and posterior palatal depths were both considered normal (P = 0.702; P = 0.373). Anterior palatal depth was increased, but not significantly (P = 0.104), whereas posterior palatal depth was reduced but also this one not significantly (P = 0.255). Discussion The aim of the present study was to evaluate the association between the maxillary dental arch transverse dimensions, palatal depths, palatal area and volume and the presence of BDC using laser scanner 3D technology to better understand the association between BDC and maxillary morphology (area and volume) for early identification and prevention of future canine impaction. The anatomical characteristics of the upper arch and palate in BDC subjects have been previously evaluated by measuring only the intercanine and intermolar widths (linear distances) (3, 7, 8). In this study, we evaluated in BDC subjects, not only the upper arch widths and depths, but also the palatal surface area and volume because these two 3D measurements have been previously reported as reliable indicators of palatal and maxillary arch growth (18). The question is whether buccal displacement of the canines is the result of the deviated growth of the maxillary complex or whether deviation in eruption is independent from morphology of the maxillary complex (8). Our results suggested that all these measurements in BDC subjects were significantly smaller compared to non-BDC subjects, implying that untreated BDC subjects in the mixed dentition showed a significantly different upper arch morphology, with a higher degree of constriction. Similarly to previous reports (3, 7), the results of our study reinforce that BDC is associated with decreased intercanine widths both at cusp and gingival levels. However, in the mixed dentition phase, no significant reduction of the intermolar widths was identified. Conversely Larsen et al. (8) in a group of DMC patients reported that the posterior transverse dimensions were significantly greater. Such results may be attributed to the heterogeneous sample of BDC and PDC. In fact, other authors (19) also reported greater posterior transverse dimensions in PDC compared with their control. To better describe the shape of the palatal vault, we also evaluated the anterior and posterior palatal depths at cusp level. The corresponding values differ between BDC and non-BDC group, but not significantly. In association with statistically reduced intercanine width, an increased anterior palatal depth could signifies that the palatal vault in BDC group is narrower and deeper in its anterior portion compared to non-BDC group. No previous studies, reported data on these parameters in BDC subjects, so a direct comparison was not possible. As the assessment of upper arch morphology based on interdental measurements does not fully consider the 3D morphological characteristics and could be biased due to axial inclination of the first molars and/or the alveolar bridge, palatal surface area and volume were used to better describe the upper arch and palate morphology using 3D laser technology as previously suggested (18). Both the palatal surface area and volume were significantly smaller in BDC than in non-BDC group. A direct comparison with other studies was not possible because our study was the first attempt to perform a 3D evaluation of palatal area and volume in untreated BDC subjects compared with untreated healthy subjects in mixed dentition phase. Therefore, we probably added a missing piece in the puzzle of the upper arch and palate morphology in BDC individuals during the development of the dentition. In fact, our results suggested that in the diagnosis of BDC cases transverse widths as well as palatal area and palatal volume must be taken into account. Upper arch constriction in BDC subjects could contribute to the aetiology of buccal canine impaction (3). In that light a 3D analysis of the upper arch can improve diagnosis and treatment of cases with BDC (18). Several methods of interceptive treatment of DMC have been described in the literature such as extraction of deciduous canine (single extraction approach), concomitant deciduous canine and first molar extractions (double extraction approach) (14, 20–22), use of maxillary expansion, transpalatal arch or headgear therapy in combination with the single or double extraction approach (22–25), often focusing on PDC (26). Transverse dimensions, palatal area and volume can be finally considered as risk indicators for developing a buccal canine impaction. Thus, according to the result of the present study, expansion, with an emphasis in the anterior reduced section of the palate, should be also considered for BDC beneficial, to increase palatal area and volume and allow normal canine eruption preventing impaction. Limitations The sample included patients both in the early and late mixed dentition phase. To overcame this potential confounder a matched control group was used. The sample included subjects who did not have some teeth, such as deciduous canines or first molars, elements required for both linear and volumetric measurement with Geomagic software, and therefore some measurements were missing. Specifically seven subjects, one in BDC group and six in the control group did not have the deciduous canine because of the transition phase, while four subjects, two in the BDC group and two in the control group did not have the first molar since they were still erupting. However, these subjects have not been excluded to avoid introducing a bias. Only those variables that were not been able to be measured were excluded from the analysis. Conclusions Subjects with BDC have a significantly reduced intercanine upper arch widths with a narrower shape of the anterior portion, while intermolar widths and depths are similar to those measured in matched subjects without BDC. Moreover also significantly smaller palatal surface area and volume were seen in untreated BDC subjects. Conflict of Interest None to declare. References 1. Litsas , G. and Acar , A . ( 2011 ) A review of early displaced maxillary canines: etiology, diagnosis and interceptive treatment . The Open Dentistry Journal , 5 , 39 – 47 . Google Scholar CrossRef Search ADS PubMed 2. Schindel , R.H. and Duffy , S.L . ( 2007 ) Maxillary transverse discrepancies and potentially impacted maxillary canines in mixed-dentition patients . The Angle Orthodontist , 77 , 430 – 435 . Google Scholar CrossRef Search ADS PubMed 3. Mucedero , M. , Ricchiuti , M.R. , Cozza , P. and Baccetti , T . ( 2013 ) Prevalence rate and dentoskeletal features associated with buccally displaced maxillary canines . European Journal of Orthodontics , 35 , 305 – 309 . Google Scholar CrossRef Search ADS PubMed 4. Sacerdoti , R. and Baccetti , T . ( 2004 ) Dentoskeletal features associated with unilateral or bilateral palatal displacement of maxillary canines . The Angle Orthodontist , 74 , 725 – 732 . Google Scholar PubMed 5. Chaushu , S. , Sharabi , S. and Becker , A . ( 2003 ) Tooth size in dentitions with buccal canine ectopia . European Journal of Orthodontics , 25 , 485 – 491 . Google Scholar CrossRef Search ADS PubMed 6. Chaushu , S. , Bongart , M. , Aksoy , A. , Ben-Bassat , Y. and Becker , A . ( 2009 ) Buccal ectopia of maxillary canines with no crowding . American Journal of Orthodontics and Dentofacial Orthopedics , 136 , 218 – 223 . Google Scholar CrossRef Search ADS PubMed 7. McConnell , T.L. , Hoffman , D.L. , Forbes , D.P. , Janzen , E.K. and Weintraub , N.H . ( 1996 ) Maxillary canine impaction in patients with transverse maxillary deficiency . ASDC Journal of Dentistry for Children , 63 , 190 – 195 . Google Scholar PubMed 8. Larsen , H.J. , Sørensen , H.B. , Artmann , L. , Christensen , I.J. and Kjaer , I . ( 2010 ) Sagittal, vertical and transversal dimensions of the maxillary complex in patients with ectopic maxillary canines . Orthodontics & Craniofacial Research , 13 , 34 – 39 . Google Scholar CrossRef Search ADS PubMed 9. Primožič , J. , Perinetti , G. , Richmond , S. and Ovsenik , M . ( 2012 ) Three-dimensional longitudinal evaluation of palatal vault changes in growing subjects . The Angle Orthodontist , 82 , 632 – 636 . Google Scholar CrossRef Search ADS PubMed 10. Primožic , J. , Baccetti , T. , Franchi , L. , Richmond , S. , Farčnik , F. and Ovsenik , M . ( 2013 ) Three-dimensional assessment of palatal change in a controlled study of unilateral posterior crossbite correction in the primary dentition . European Journal of Orthodontics , 35 , 199 – 204 . Google Scholar CrossRef Search ADS PubMed 11. Primozic , J. , Ovsenik , M. , Richmond , S. , Kau , C.H. and Zhurov , A . ( 2009 ) Early crossbite correction: a three-dimensional evaluation . European Journal of Orthodontics , 31 , 352 – 356 . Google Scholar CrossRef Search ADS PubMed 12. Baccetti , T. , Franchi , L. and McNamara , J.A. , Jr . ( 2005 ) The cervical vertebral maturation (CVM) method for the assessment of optimal treatment timing in dentofacial orthopedics . Seminars in Orthodontics , 11 , 119 – 129 . Google Scholar CrossRef Search ADS 13. Lindauer , S.J. , Rubenstein , L.K. , Hang , W.M. , Andersen , W.C. and Isaacson , R.J . ( 1992 ) Canine impaction identified early with panoramic radiographs . Journal of the American Dental Association (1939) , 123 , 91 – 92, 95 . Google Scholar CrossRef Search ADS PubMed 14. Power , S.M. and Short , M.B . ( 1993 ) An investigation into the response of palatally displaced canines to the removal of deciduous canines and an assessment of factors contributing to favourable eruption . British Journal of Orthodontics , 20 , 215 – 223 . Google Scholar CrossRef Search ADS PubMed 15. Maverna , R. and Gracco , A . ( 2007 ) Different diagnostic tools for the localization of impacted maxillary canines: clinical considerations . Progress in Orthodontics , 8 , 28 – 44 . Google Scholar PubMed 16. Martorelli , M. , Maietta , S. , Gloria , A. , De Santis , R. , Pei , E. and Lanzotti , A . ( 2016 ) Design and analysis of 3D customized models of a human mandible . Procedia CIRP , 49 , 199 – 202 . Google Scholar CrossRef Search ADS 17. Shah , M. , Verma , A.K. and Chaturvedi , S . ( 2014 ) A comparative study to evaluate the vertical position of maxillary central incisor and canine in relation to incisive papilla line . Journal of Forensic Dental Sciences , 6 , 92 – 96 . Google Scholar CrossRef Search ADS PubMed 18. Generali , C. , Primozic , J. , Richmond , S. , Bizzarro , M. , Flores-Mir , C. , Ovsenik , M. and Perillo , L . ( 2017 ) Three-dimensional evaluation of the maxillary arch and palate in unilateral cleft lip and palate subjects using digital dental casts . European Journal of Orthodontics , 39 , 641 – 645 . Google Scholar CrossRef Search ADS PubMed 19. Al-Nimri , K. and Gharaibeh , T . ( 2005 ) Space conditions and dental and occlusal features in patients with palatally impacted maxillary canines: an aetiological study . European Journal of Orthodontics , 27 , 461 – 465 . Google Scholar CrossRef Search ADS PubMed 20. Williams , B.H . ( 1981 ) Diagnosis and prevention of maxillary cuspid impaction . The Angle Orthodontist , 51 , 30 – 40 . Google Scholar PubMed 21. Ericson , S. and Kurol , J . ( 1988 ) Early treatment of palatally erupting maxillary canines by extraction of the primary canines . European Journal of Orthodontics , 10 , 283 – 295 . Google Scholar CrossRef Search ADS PubMed 22. Alessandri Bonetti , G. , Incerti Parenti , S. , Zanarini , M. and Marini , I . ( 2010 ) Double vs single primary teeth extraction approach as prevention of permanent maxillary canines ectopic eruption . Pediatric Dentistry , 32 , 407 – 412 . Google Scholar PubMed 23. Leonardi , M. , Armi , P. , Franchi , L. and Baccetti , T . ( 2004 ) Two interceptive approaches to palatally displaced canines: a prospective longitudinal study . The Angle Orthodontist , 74 , 581 – 586 . Google Scholar PubMed 24. Baccetti , T. , Leonardi , M. and Armi , P . ( 2008 ) A randomized clinical study of two interceptive approaches to palatally displaced canines . European Journal of Orthodontics , 30 , 381 – 385 . Google Scholar CrossRef Search ADS PubMed 25. Baccetti , T. , Mucedero , M. , Leonardi , M. and Cozza , P . ( 2009 ) Interceptive treatment of palatal impaction of maxillary canines with rapid maxillary expansion: a randomized clinical trial . American Journal of Orthodontics and Dentofacial Orthopedics , 136 , 657 – 661 . Google Scholar CrossRef Search ADS PubMed 26. Baccetti , T. , Sigler , L.M. and McNamara , J.A. , Jr . ( 2011 ) An RCT on treatment of palatally displaced canines with RME and/or a transpalatal arch . European Journal of Orthodontics , 33 , 601 – 607 . Google Scholar CrossRef Search ADS PubMed © The Author(s) 2018. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices)

Journal

The European Journal of OrthodonticsOxford University Press

Published: May 3, 2018

There are no references for this article.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off