Bruno Frazão Gribel

Maxillofacial Features Related to Mandibular Asymmetries in Skeletal Class III Patients

PURPOSE To analyze components related to different degrees of mandibular asymmetry in adults with skeletal Class III using cone-beam computed tomographic (CBCT) images. MATERIALS AND METHODS CBCT images from 138 patients were analyzed. Asymmetry was determined by the deviation of the gnathion point in relation to the midsagittal plane and classified as relative symmetry, moderate mandibular asymmetry, or severe mandibular asymmetry. Several maxillary and mandibular measurements were used to compare different degrees of mandibular asymmetry and the difference between measurements of the contralateral and deviated sides. RESULTS For patients with moderate and severe mandibular asymmetry, there were statistically relevant differences between bilateral measurements of the sagittal position of the condylar heads, the transverse and sagittal positioning of the gonion, ramus height, and mandibular body length, the transverse and vertical positioning of the jugale point, including a vertical positioning of the gonion only for severe asymmetry. In patients with severe mandibular asymmetry, there was a highly relevant correlation of gnathion lateral displacement with lower dental midline displacement and with the difference in height of the mandibular rami between the deviated and contralateral sides. CONCLUSION In patients with skeletal Class III, not only lateral displacement of the menton but also a series of morphologic changes differed markedly for each degree of mandibular asymmetry.

Stability of extraction space closure.

INTRODUCTION The objectives of this study were to evaluate the prevalence and long-term behavior of extraction space reopening in patients with Class I malocclusion and to identify some associated factors. METHODS A sample of 43 patients met the inclusion criteria. Dental casts at the onset of treatment, after treatment, and 1 and 5 years after debonding were used. Initial and final cephalometric radiographs were used to measure the amount of incisor retraction. Cochran tests were used to compare the numbers of open and closed extraction spaces after treatment and at 1 and 5 years after debonding (P <0.05). Initial incisor crowding, amounts of anterior retraction, and angulations between the canines and the second premolars were compared between patients with and without space reopening with t tests. RESULTS Of the sample, 30.23% had extraction space reopening. The frequency of open spaces significantly increased between the final and the 1-year posttreatment dental casts and decreased between the casts at 1 and 5 years posttreatment. Patients with space reopening had less initial anterior crowding and greater amounts of mandibular incisor retraction during treatment. CONCLUSIONS There was a high prevalence of space reopening 1 year after treatment. However, these spaces tended to decrease by 5 years after treatment.

Mandibular asymmetries and associated factors in orthodontic and orthognathic surgery patients

OBJECTIVES To estimate the prevalence of mandibular asymmetries in orthodontic and orthognathic surgery patients and to investigate demographic and skeletal factors associated with this disharmony. MATERIALS AND METHODS Cone-beam computed tomography images of 1178 individuals aged 19 through 60 years with complete dentitions were analyzed. Outcomes were classified as relative mandibular symmetry, moderate asymmetry, and severe asymmetry. Factors recorded included sex, age, side of mandibular deviation, sagittal jaw relationship, vertical skeletal pattern, angle of the cranial base, and maxillary asymmetry. Ordinal logistic regression was used to estimate simple and adjusted odds ratios (OR) for the individuals with moderate and severe mandibular asymmetry, as well as 95% confidence intervals. RESULTS Prevalence values of 55.2%, 27.2%, and 17.6% were observed for relative mandibular symmetry, moderate asymmetry, and severe asymmetry, respectively. An independent association with the side of mandibular deviation and the presence of maxillary asymmetry was observed, both for subjects with moderate mandibular asymmetry (left side: OR = 1.50; 95% CI: 1.01-2.24 / maxillary asymmetry: OR = 2.07; 95% CI: 1.11-3.76) and for those with severe asymmetry (left side: OR = 2.09; 95% CI: 1.27-3.44 / maxillary asymmetry: OR = 4.93; 95% CI: 2.64-9.20). CONCLUSIONS Moderate and severe mandibular asymmetries were present in 44.8% of the sample, being associated with the side of mandibular deviation and with maxillary asymmetry.

Prevalence and Associated Factors of Mandibular Asymmetry in an Adult Population.

Background: This study aimed to estimate the prevalence of mandibular asymmetry and investigate some associated factors. Methods: Tomographic images of 952 individuals aged from 18 to 75 years old were analyzed. The investigated outcome was mandibular asymmetry. The explanatory variables included gender, age, absence of posterior teeth, and sagittal jaw relationship of the individuals. Statistical analyses included the chi-squared and the Poisson regression with robust variance. Results: Mandibular asymmetry was present in 17.4% of the sample (95% confidence interval 15.2–20.0). In the bivariate analysis, there was an association between the variables age and sagittal jaw relationship with mandibular asymmetry (P = 0.026 and P = 0.018, respectively). However, in the adjusted regression model, the association with age was not maintained, occurring only an association between sagittal jaw relationship and mandibular asymmetry (P = 0.045), with significant difference between individuals with skeletal Class II and skeletal Class III (P = 0.013). Conclusion: Mandibular asymmetry was not independently associated with sex, age, or absence of posterior teeth. The only verified independent association was between mandibular asymmetry and sagittal jaw relationship.BACKGROUND This study aimed to estimate the prevalence of mandibular asymmetry and investigate some associated factors. METHODS Tomographic images of 952 individuals aged from 18 to 75 years old were analyzed. The investigated outcome was mandibular asymmetry. The explanatory variables included gender, age, absence of posterior teeth, and sagittal jaw relationship of the individuals. Statistical analyses included the chi-squared and the Poisson regression with robust variance. RESULTS Mandibular asymmetry was present in 17.4% of the sample (95% confidence interval 15.2-20.0). In the bivariate analysis, there was an association between the variables age and sagittal jaw relationship with mandibular asymmetry (P = 0.026 and P = 0.018, respectively). However, in the adjusted regression model, the association with age was not maintained, occurring only an association between sagittal jaw relationship and mandibular asymmetry (P = 0.045), with significant difference between individuals with skeletal Class II and skeletal Class III (P = 0.013). CONCLUSION Mandibular asymmetry was not independently associated with sex, age, or absence of posterior teeth. The only verified independent association was between mandibular asymmetry and sagittal jaw relationship.

Three-dimensional evaluation of craniofacial characteristics related to mandibular asymmetries in skeletal Class I patients

Introduction: Our objective was to analyze the characteristics that affect skeletal Class I adults with mandibular asymmetries using cone‐beam computerized tomography. Methods: The sample included cone‐beam computerized tomography images of 120 subjects. Asymmetry was determined by the deviation of gnathion from the midsagittal plane and classified as relative symmetry, moderate asymmetry, or severe asymmetry. Maxillary and mandibular measurements were made, and the differences between the contralateral side and the deviated side were evaluated, as well as the differences between the categories of asymmetry. Results: For patients with moderate asymmetry, there were significant differences between the contralateral and deviated sides for some measuments in the transverse and vertical planes. For those with severe asymmetry, statistically significant differences were found between the sides for all measurements, except for the measuments that evaluated the position of the mandibular condyle in the transverse and sagittal directions. Furthermore, a strong correlation was found in patients with severe asymmetry, between the deviation of the mandibular dental midline and the lateral displacement of gnathion. Conclusions: Patients with relative symmetry had a bilateral balance, whereas those with moderate and severe asymmetries showed several skeletal imbalances. A great deviation of the mandibular dental midline may indicate severe skeletal asymmetry in Class I adults. HIGHLIGHTSMandibular asymmetry presents morphologic features, notably lateral chin deviation.Patients with relative symmetry differed from those with moderate or severe asymmetry.Lower midline and gnathion deviations were correlated in Class I patients with severe asymmetry.