ABSTRACT
OBJECTIVE@#We aim to examine teenagers with varying vertical facial skeletal types with near-normal occlusion. We further aim to identify and study mandibular morphology and dentition characteristics to establish normal ranges and variations for future clinical reference.@*METHODS@#According to the results of the case studies, 42 adolescents with near-normal occlusion were divided into three groups, namely, low- (7 cases), average- (23 cases) and high-angle (12 cases) groups. We used Invivo 5 software for Digital Imaging and Communications in Medicine (DICOM) data to calculate the cant of occlusal plane, axis corner of L6, ∠L1/MP, ∠L6/MP, Balkwill angle and Bonwill triangle of each group.@*RESULTS@#Markedly, the finding shows that the cant of occlusal plane and axis corner of L6 in the low-angle group were smaller than those of the other two groups. In the average-angle group, ∠L1/MP was larger than that of the high-angle group. Lastly, in the high-angle group, ∠L6/MP was smaller than those of the two other groups. On the one hand, these differences were considered statistically significant (P0.05).@*CONCLUSIONS@#In the low-angle group, the parallelisation of the occlusal plane tends to be more obvious compared with the two other groups. In the coronal section of the low-angle group, the axis of the mandibular first molar is up-right, whereas it is distally tilted in the sagittal section of the high-angle group. Furthermore, a number of differences are noted in the adult groups. Factors, such as aging and development in the craniofacial region, lead to changes in functional occlusion.
Subject(s)
Adolescent , Humans , Cephalometry , Dental Occlusion , Dentition , Mandible , ToothABSTRACT
Objective The aim of our work is to characterize individual normal occlusions to establish appropriate treatment standards for different vertical facial types. Methods A total of 30 patients with near-normal occlusion were grouped into high-angle group (eight cases), medium-angle group (12 cases), and low-angle group (10 cases) according to vertical facial skeletal type. Invivo5 software was used and digital imaging and communications in medicine data were rebuilt to measure the ∠L1/MP, ∠L6/MP, axis corner of L6, cant of occlusion plane, Balkwill angle, and Bonwill triangle of each group. Results Among the groups, the low-angle group had the smallest ∠L6/MP (P<0.05) and largest cant of occlusion. No significant difference was observed among the three groups with regard to the other parameters (P>0.05). Conclusion Patients with low-angle vertical facial skeletal type requires a modified treatment standard. In this group, the treatment standard must ensure that the cant of occlusion plane is more parallel to the Frankfurt horizontal plane compared with those of the other groups, and the axis of L6 is tilted distally relative to the mandibular plane.
ABSTRACT
Objective:To analyze the correlation between arch width and different vertical facial skeletal types of the adults with individual normal occlusion.Methods:52 adults with individual normal occlusions(females 31,males 21) were included.According to the values of mandibular plane angle MP-FH,SN-MP measured on CBCT image the subjects were divided into 3 groups(13 cases with highangle,19 with average-angle and 20 with low-angle groups).12 parameters were measured for each sample,including maxillary and mandible arch width and alveolar arch width between canines,between first premolars and between first molars,the difference between the maxillary arch width and mandibular arch width were calculated.The data were statistically analyzed by one-way ANOVA and Pearson~ rank correlation test.Results:In the group of high-angle,average-angle and low-angle the alveolar arch width(mm) between maxillary canines was 38.03 ± 1.90,39.65 ± 1.80 and 39.78 ± 2.20 respectively(P ＜ 0.05).The arch width between maxillary first premolars of high-angle group(37.01 ± 1.60) was smaller than that of low-angle group(38.65 ± 1.30).The arch width difference in canine area between maxillary and mandibular alveolar in high-angle,average-angle and low-angle groups was 7.39 ± 1.82,9.04 ± 1.43 and 9.26 ± 1.67 respectively(P ＜0.05);in maxillary first premolars area in high-angle(6.8 ± 1.59) was smaller than that in averageangle(7.79 ± 1.09),maxillary and mandibular arch width showed no statistical difference.Pearson correlation test showed that among 3 groups,upper and lower alveolar arch width difference in canine and first premolars area was negatively correlated with the mandibular plane angle.while upper and lower arch width difference showed no statistical correlation with the mandibular plane angle.Conclusion:The maxillary middle arch width of the subjects with individual normal occlusion was correlated with vertical facial type.
ABSTRACT
BACKGROUND:Posterior arch length deficiency is closely related to the formation and development of malocclusion. OBJECTIVE:To measure the posterior arch length in individual normal occlusions of adults in Lanzhou. METHODS:A total of 102 current col ege students with individual normal occlusions, with a mean age of (19.33±2.67) years (range 18-24 years), including 47 males and 55 females from Gansu Province, were chosen to take lateral cephalograms. Al research objects were divided into three groups according to mandibular plane angle:high angle group (Frankfort mandibular-plane angle>32°), low angle group (Frankfort mandibular-plane angleRESULTS AND CONCLUSION:Posterior arch length of maxil ary arch was slightly longer in male group than that in female group, and the difference was not significant (P>0.05). The posterior arch length of mandibular arch was slightly longer in male group than that in female group, but the difference was no significant (P>0.05). Comparison between groups revealed that the posterior arch length of low angle mandibular arch was significantly longer than that of high angle mandibular arch in male group, and the difference was significant (P<0.05). The results indicate that the gender wil not influence the development of posterior arch length. Different vertical facial types and different genders have different posterior arch length in individual normal occlusions of adults