Heritability of mandibular asymmetries in sagittal direction: A cephalometric study.

AIM OF THE WORK: If we figure out mandible asymmetry etiology, we can inspire further scientific research, create more effective treatment schemas and recommend means of prophylaxis that could stop mandible asymmetry development. The aim of this work was to analyze monozygotic and dizygotic twins' mandibular asymmetry in sagittal direction using cephalometric data and to analyze its dependence of genetic and environmental factors. MATERIAL AND METHODS: Study sample consisted of 80 dizygotic (DZ) and 80 monozygotic (MZ) twins of same sex. 3 cephalometric measurements were made to determine mandible asymmetry in sagittal direction. Indexes of mandibular asymmetry (IMA1, IMA2) were calculated. Data analysis was done using Microsoft Excel (2013). Genetic and environmental factors influencing mandible asymmetry was determined. RESULTS: Mandibular dental asymmetry was bigger in monozygotic twins' group but the results were not statistically significant. Mandibular skeletal asymmetry was significantly bigger in dizygotic twins' group: IMA1(DZ)=3.05±1.94, IMA1(MZ)=1.92±1.05, p=0.005. IMA2(DZ)=3.12±2.04, IMA2(MZ)=1.88±1.04, p=0.004. Distance between distal borders of the ramus is mostly determined by genetic factors. CONCLUSIONS: 1. Mandibular skeletal asymmetry was significantly bigger in dizygotic twins' group. Mandibular dental asymmetry and symmetry did not differ in groups significantly. 2. Skeletal mandible's asymmetry is more determined by genetics than environmental factors, but lower molars' sagittal position is determined more by environment.

Orthodontic treatment complexity, outcome and need among school age patients of Lithuanian university of health sciences clinic of orthodontics.

AIM OF THE WORK: It has not been any well-documented study describing the prevalence of orthodontic anomalies between school-age children seeking orthodontic treatment at LUHS (Lithuanian university of health sciences) clinic of Orthodontics. Our aim was to assess the prevalence of orthodontic problems and to determine orthodontic treatment need, complexity and outcome for school-age patients who were treated at LUHS clinic of Orthodontics. MATERIAL AND METHODS: Our study sample consists of 336 scholars 6-19 years old who were treated at LUHS clinic of orthodontics from 2013 to 2018. ICON index is used to determine the complexity, outcome and need of orthodontic treatment. Statistical analysis is performed using the statistical software package IBM SPSS Statistics 24.0. Quantitative variable distribution is assessed visually and by using the Shapiro-Wilk test. RESULTS: The estimated need for orthodontic treatment is 56.3 percent among patients. The need of treatment for 6-10 year old group is significantly higher than for 11-14 and 15-19 groups (69.0, 52.3 and 51.2 percent). In the group of 11-14 year olds the need of treatment between boys and girls differs significantly (63.1 percent in boy group, 43.8 percent in girl group). Moreover in the 11-14 year old group, the complexity of treatment "easy" is more frequent than in the 6-10 group. CONCLUSIONS: The need of orthodontic treatment is 56.3 percent among subjects treated in LUHS clinic of orthodontics from 2013 to 2018. In all age groups the complexity of treatment is mostly "easy" or "mild".