ABSTRACT
OBJECTIVE: The purpose of this study was to measure the thickness of the palatal bone using cone beam computed tomography images for placement of mini-screws and their relationship with palatal vault depth. METHODS: This study was performed on 150 maxillary cone beam computed tomography images, 50% (n = 75) had deep palate and 50% (n = 75) had normal palate and 27.3% (n = 41) were male and 72.7% (n =109) were female. Coronal sections with a thickness of 1 mm were prepared at distances of 4 mm, 8 mm, 12 mm, 16 mm, 20 mm, and 24 mm from the posterior wall of the incisive foramen. Then, in each section, in the midsagittal line and at distances of 2 mm, 4 mm, 6 mm, 8 mm, and 10 mm from that to the lateral sides, the bone thickness was measured. The Korkhaus index was used to identify the patients with a high palatal vault. RESULTS: The results showed that at the posterior sections in the midsagittal and parasagittal area, a significant difference (P < .05) was observed between deep and normal palate, and in these points, the bone thickness in the normal palate was greater. Also, in the section of 4 mm and 8 mm, a significant difference was observed between males and females in most of these points, and those were greater in males than females. CONCLUSION: The maximum thickness of the palatal bone was observed first along the midsagittal line and then the paramedian and in the anterior section. Patients with deep palate had less palatal bone thickness in the posterior sections.
ABSTRACT
BACKGROUND: New tools have been introduced for tooth inclination measurement and assessment of its changes over time. This study aimed to measure the change in inclination of teeth after the periods of 2 and 4 years in adolescents with normal occlusion using three-dimensional (3D) software. MATERIALS AND METHODS: This retrospective longitudinal study was conducted on 54 pairs of dental casts of 24 adolescents between 9 and 13 years of age with normal occlusion. The inclination of teeth was determined by 3D measurements using OrthoAid software. After scanning the casts via stereophotogrammetric scanner, the mean and standard deviation of inclination of teeth were calculated at three time points. Change in these values was calculated after 2 and 4 years. The effect of sex, duration of follow-up, and the jaw (maxilla/mandible) on change of inclination was analyzed using the Mann-Whitney and Wilcoxon tests. P < 0.05 was considered statistically significant. RESULTS: Incisor teeth torque was positive in the maxilla (9.72 ± 8) and mandible (4.22 ± 6.09), but it was negative for the canine (-7.73 ± 6.3 for maxilla and -9.9 ± 5.22 for mandible), premolar (-10.35 ± 6.84 for maxilla and -26.51 ± 9.94 for mandible), and molar teeth (-13.23 ± 6.22 for maxilla and -39.78 ± 9.5 for mandible) in both jaws. Maxillary lateral incisor in boys showed the greatest change of inclination in both 2 and 4 years (about 7°) and the mandibular canine tooth in girls showed the least change of inclination in 4 years (4°). CONCLUSION: Sex significantly affected the changes in the inclination of teeth throughout the period of study. The variation of changes in torque was considerable, and no consistent pattern was defined.
