Background This study aimed to assess the interradicular distance and alveolar bone thickness of Persian adults with different sagittal skeletal patterns for miniscrew insertion using cone-beam computed tomography (CBCT). Methods This cross-sectional study was conducted on maxillary and mandibular CBCT scans of 60 patients (18–35 years) in three groups (n = 20) of class I, II and III sagittal skeletal pattern. Anatomical and skeletal parameters were measured at 2, 4 and 6 mm apical to the cementoenamel junction (CEJ) by one examiner. The intra- and inter-class correlation coefficients were calculated to assess the intra, and interobserver reliability. Data were analyzed by ANOVA and Tukey’s test (alpha = 0.05). Results The intra- and interobserver reliability were > 0.9 for all parameters. The largest inter-radicular distance in the maxilla was between the central incisors (1–1) in classes I and III, and between premolars (4–5) in class II patients. The largest inter-radicular distance in the mandible was between molar teeth (6–7) in all three classes. The buccal cortical plate thickness was maximum at the site of mandibular first and second molars (6–7). The posterior maxilla and mandible showed the maximum thickness of cancellous bone and alveolar process. Wide variations were noted in this respect between class I, II and III patients. Conclusions The area with maximum inter-radicular distance and optimal alveolar bone thickness for miniscrew insertion varies in different individuals, depending on their sagittal skeletal pattern.

AIM: This study compared the effect of traditional and virtual oral hygiene instruction to school health instructors on plaque index (PI) of elementary schoolchildren. METHODS AND MATERIALS: In this descriptive, analytical study, 66 elementary schools in Kermanshah city were selected by cluster sampling. The school health instructors first participated in a pretest and filled out a questionnaire. The O’Leary’s index of 339 elementary schoolchildren was measured at baseline. Next, the school health instructors received oral hygiene instructions in two groups (n = 33) of virtual instruction through an online course and traditional classroom setting. After 3 weeks, a post-test was held and school health instructors filled out the same questionnaire for the 2nd time. After 3 months, the PI of students was measured again. Data were analyzed using the Chi-square test, t-test, Mann–Whitney U-test, and ANOVA. RESULTS: Both instruction methods significantly enhanced the oral hygiene knowledge of instructors (p < 0.001) but virtual instruction was significantly more effective (p = 0.02). No significant association was noted between age, work experience of instructors, or their level of education with their knowledge level in the virtual group (p > 0.05). An inverse correlation was noted between age and work experience of instructors with their knowledge level in the traditional instruction group (p < 0.05). Both instruction methods caused significant improvement of PI of students (p < 0.001) but virtual instruction was more effective (p < 0.001). CONCLUSION: Correct oral hygiene instruction to school health instructors (preferably by virtual instruction) can reduce PI elementary schoolchildren.