Prevalence of mandibular asymmetry in different skeletal sagittal patterns:

ABSTRACT Objectives To analyze the prevalence of mandibular asymmetry in skeletal sagittal malocclusions. Materials and Methods PubMed/MEDLINE, EMBASE, LILACS, Web of Science, Scopus, LIVIVO and gray literature (OpenGrey, ProQuest, and Google Scholar) were electronically searched. Two independent investigators selected the eligible studies, and assessed risk of bias and certainty of evidence (GRADE). One reviewer independently extracted the data and the second reviewer checked this information. Any disagreement between the reviewers in each phase was resolved by discussion between them and/or involved a third reviewer for final decision. Results Electronic search identified 5,132 studies, and 5 observational studies were included. Risk of bias was low in two studies, moderate in one, and high in two. The studies showed high heterogeneity. Mandibular asymmetry ranged from 17.43% to 72.95% in overall samples. Horizontal chin deviation showed a prevalence of 17.66% to 55.6% asymmetry in Class I malocclusions, and 68.98% in vertical asymmetry index. In Class II patients, prevalence of mandibular asymmetry varied from 10% to 25.5% in horizontal chin deviation, and 71.7% in vertical asymmetry index. The Class III sample showed a prevalence of mandibular asymmetry ranging from 22.93% to 78% in horizontal chin deviation and 80.4% in vertical asymmetry index. Patients seeking orthodontic or orthognathic surgery treatment showed greater prevalence of mandibular asymmetry. Conclusions Skeletal Class III malocclusion showed the greatest prevalence of mandibular asymmetry. Mandibular vertical asymmetry showed a marked prevalence in all malocclusions. However, conclusions should be interpreted with caution due to use of convenience samples and low-quality study outcomes.

Surgical-Orthodontic Diagnosis and Treatment Planning in an Asymmetric Skeletal Class III Patient—A Case Report

The skeletal Class III pattern is characterized by a sagittal intermaxillary mesial discrepancy. This discrepancy may have an unfavorable impact on function and aesthetics, which can be aggravated by the presence of facial asymmetries. This case report describes the diagnosis and treatment planning of a 19-year-old male patient with a skeletal Class III, maxillary hypoplasia, anterior crossbite, and mandibular asymmetry. When the patient reached skeletal maturity at the end of puberty, the definitive diagnosis was skeletal Class III with hyperdivergent profile and mandibular asymmetry, and a surgical-orthodontic treatment was proposed. At the end of the treatment, bimaxillary surgical correction allowed a skeletal Class I with mandibular symmetry, improving the function of the stomatognathic system and facial aesthetics.

Relationship Between Maxillary Sinus Hypoplasia and Maxillary Occlusal Cant: A Cone Beam CT Study

Background: maxillary sinus hypoplasia (MSH) has been reported to cause a cant in the orbital plane. No similar reports exist about the possible impact on the maxilla. The aim of this study was to assess if MSH is associated with maxillary occlusal plane (MOP) cant, and if dental or mandibular factors influenced the existence of the MOP cant. Methods: 80 cone beam CT images of subjects with MSH were analyzed for type of MSH, degree of MOP cant, open or cross bite, mandibular asymmetry, and degenerative joint disease of the temporomandibular joints. The subjects were compared with a control group matched by age and gender. Results: The degree of MOP cant (range 0-5.1°) was not statistically significantly different in unilateral vs bilateral MSH, or between the different types of MSH. The frequency of open bite, crossbite, mandibular asymmetry, or degenerative joint disease in unilateral vs bilateral MSH, or between the different types of MSH was not statistically significantly different. Between the case and control, there was no statistically significant difference in the degree of MOP cant (1.3±1.1° vs 1.1±0.9°, respectively), or frequency of dental and mandibular factors. There was low positive linear correlation between MOP cant and mandibular symmetry in MSH subjects (Spearman’s rho= 0.23) and controls (Spearman’s rho= 0.187). Conclusions: The data suggests a view of the alveolar bone as the adaptable skeletal unit to ensure and bridge the functionality between the nasomaxillary complex and TMJ system – two systems with very different function, and therefore largely independent “matrix units”.

CBCT Evaluation in a Growing Patient With Mandibular Asymmetry Treated With Rapid Palatal Expander and Frankel-III. Case Report.

BackgroundThis study aims to evaluate the development and the compensation mechanisms of the mandibular asymmetry in a growing patient, using Cone Beam Computed Tomography (CBCT). In this case, the menton was deviated on the right, an extremely rare condition, which may be the consequence of a disorder in the mandibular growth. Case presentationThe patient was treated with Rapid Palatal Expander (RPE) and Fränkel Functional Regulator III (FR-3). The initial CBCT was acquired at the beginning of therapy, when patient was 8 years old (y.o), the final CBCT was acquired at the end of the treatment, when patient was 12 y.o. Patient’s CBCT was performed with the head oriented according to the Natural Head Position (NHP); the NHP is a physiological and reproducible posture defined for morphological analysis.The 3D image of the cranium was oriented in the Dolphin software according to NHP posture; the cephalometric measurements were performed in frontal, laterolateral right and left, posteroanterior and submentovertex views in the aforementioned software. The therapy lasted 3.8 years and ended with a significant regression of the mandibular asymmetry from moderate grade (4.2 mm) to slight grade (1.3 mm). Conclusion The left hemi-mandible has grown more than right side, in accordance with the literature, which affirm that in case of deviation of the menton greater than 4 mm, the bone volume increases on the nondeviated side.

Radiologic Evaluation of Odontometric and Osteologic Traits for Gender Determination in Adult Ethnic Tamil Population

Background: Odontometric and osteologic trait have always served as an excellent resource in anthropological, genetic, odontologic, and forensic investigations. Traits: The aim of this study was to find the most reliable method for gender determination by correlating both the odontometric and osteologic variables. Materials and Methods: A retrospective study was conducted using digital panoramic radiographs of 400 individuals (200 males and 200 females) with age ranging from 20 to 50 years. Standardized digital panoramic radiographs of patients taken as part of pretreatment planning for implants, extractions of third molars, and for periodontal diseases were selected from the archives. Measurements were done using IMAGE Pro software. Results: Mesiodistal width of 17–47 exhibited significant gender variation. Osteologic parameters such as ramus dimension and the gonial angle also showed significant gender variation and the mandibular asymmetry was significant in both the genders. Conclusion: Correlation of the two group of traits showed strong positive predictive values attributable for gender determination.