Influence of maxillary posterior dentoalveolar discrepancy on angulation of maxillary molars in individuals with skeletal open bite

Comparison of mesiodistal angulations of premolars and molars in anterior open bite subjects with different sagittal malocclusions: A retrospective study

INTRODUCTION

Mesiodistal angulation of premolars and molars can be altered by forces of open bite malocclusion. The aim of this study was to compare the mesiodistal angulations of the posterior teeth in class I, II, and III individuals with anterior open bite (AOB) versus individuals with harmonious occlusion.

METHODS

This comparative cross-sectional study used 299 lateral head radiographs of individuals with permanent dentition. There were 4 groups (harmonious occlusion [n=89], Class I open bite [OB] [n=75], Class II OB [n=66], and Class III OB [n=69]). Premolar (1UPM, 2UPM) and molar (1UM, 2UM) angulations were measured relative to the occlusal plane and the palatal or mandibular plane by a trained and calibrated evaluator. ANOVA and Scheffe tests were used for statistical analyses (P<0.05).

RESULTS

The mesial angulation of the upper premolars showed greater angulation of between approximately 2° and 5° in the OB groups compared to the harmonious occlusion group (P<0.05). Only in the Class II OB group did the first and second upper molars show distal angulation in relation to the palatal plane (1UM 81.85°±5.42°; 2UM 75.32±7.4°) (P<0.05). The Class III OB group presented the greatest distal angulations of the lower premolars and molars (between 3° to 5° of difference, P<0.05) in relation to those of the harmonious occlusion group.

CONCLUSIONS

The upper first premolars in all the AOB groups and the lower second premolars in the Class II OB group had greater mesioangulation. Additionally, the upper molars of the Class II OB group and the lower molars of the Class III OB group showed distoangulation compared with the molars in the group with harmonious occlusion.

Analysis of Variations in Maxillary Second Molar Buccopalatal Inclination in Angle's Class I, Angle's Class III Malocclusion, and Unilateral Cleft Lip and Palate (UCLP) Cases: A Comparative Observational Study

Introduction Cleft of the lip and/or the palate is commonly inherited defect which involves cleft of lip and palate. Maxillary second molar inclination has been studied in various malocclusion. Every abnormality in body is compensated to some extend by compensation. Our objectives were to evaluate maxillary second molar inclination in Angle's Class I, Class III malocclusion, and unilateral cleft lip and palate (UCLP) patients in transverse plane and to compare variation in maxillary second molar inclination in Angle's Class I, Class III malocclusion, and UCLP cases buccopalatally in transverse plane. Material and method Model of 45 subjects were analyzed. The maxillary second molar inclination was measured using aid of protractor fixed on the surveyor. Axis under consideration was the axis along the long axis of the central fossa of maxillary second molar. Various standardization regarding measurement of second molar inclination were set. The maxillary second molar inclination was compared among 3 groups Angle's Class I, Class III malocclusion, and UCLP cases. Results Data was analyzed using one-way analysis of variance (ANOVA) and post-hoc Tukey test. There was a significant difference between inclination of maxillary second molar when Angle's Class I malocclusion was compared with Angle's Class III malocclusion and UCLP cases (p = 0.003 and p = 0.011, respectively). There was not a significant difference between Angle's Class III malocclusion and UCLP cases (p = 0.87). Conclusion Amongst Class III patients and UCLP patients the inclination of maxillary second molar had greater buccal inclination. Maxillary second molar correction would alleviate the effect of deleterious force on periodontium and bone generated by malpositioned teeth.

Mesiodistal Angulation of Each Whole Tooth in Patients With Nonsyndromic Unilateral Cleft Lip and Palate: Is it Symmetrical?

OBJECTIVE

To assess the symmetry of the mesiodistal angulations of maxillary and mandibular teeth in patients with unilateral cleft lip and palate (UCLP) and compare with the class I control group without cleft lip and palate (CLP).

DESIGN

A retrospective study.

SETTING

University department.

PATIENTS, PARTICIPANTS

The panoramic radiographs of 45 orthodontically untreated individuals with nonsyndromic UCLP (mean age 14.13 ± 0.75 years) and 45 skeletal class I individuals without CLP (mean age 14.01 ± 0.74 years).

INTERVENTIONS

The line passing through the most superior points of the condyles was taken as the reference. The angle between the long axes of the maxillary and mandibular teeth and reference line was measured digitally. With the purpose of determining condylar symmetry, mandibular asymmetry index measurements were utilized. Independent samples t test and paired samples t test were used for the statistical analyses.

MAIN OUTCOME MEASURE(S)

The mesiodistal angulation of the maxillary and mandibular teeth in patients with UCLP was measured. The differences between the contralateral sides were determined and compared to class I individuals without CLP.

RESULTS

No statistically significant difference was found among the condylar asymmetry in both groups (P > .05).The significant differences between the cleft and noncleft sides in the UCLP group was observed in the maxillary central, canine, first premolar and second molar teeth (P < .001, P = .002, P = .013, P = .012, respectively). The mean differences were found to be higher in the central and lateral incisors, canines and first premolars in the UCLP group (P < .001, P = .006, P = .001, respectively).

CONCLUSIONS

Although the cleft-side maxillary central incisors tipped in a distal direction in patients with UCLP, the canine and first premolar showed more inclinations toward the mesial direction.