Cephalometric correlation between facial dimensions and sagital and vertical position of anterior teeth

Description of relationship between dental and skeletal parameters can help diagnosis and treatment of malocclusions. This study evaluated the relationship between facial height and vertical and sagital position of anterior teeth. The lateral cephalogerams of 89 patients between ages of 14 to 18 years old were studied. The study casts were analyzed then samples were divided into 2 groups of with or without crowding. Cephalograms were traced and Pearson correlation was determined between parameters that explain facial dimensions and parameters that showed sagital and vertical position of anterior teeth. High correlation was found between ANB and Ul to SN, Ul to FH, and Ui to NA [mm]. SNB had also correlation with Ui to FH and Ul to SN. Additionally, Jaraback index showed a great correlation with L to MP, IMP A and SNB. FMA was similarly correlated with IMP A and FMIA. Significant correlation was detected between basal angle and IMP A [P< 0.001]. The remaining subjects did not have crowding and demonstrated high correlation between ANB and LI to NB. SN-GoGn displayed a great correlation with SNB and FMIA. Ui to FH was highly correlated with FMA, SN-GoGn and L! to MP. High correlation was observed between LI to NB [mm] and LI to MP [P<0.001]. There was correlation between position of anterior teeth and facial dimensions that confirms the existence of balance between dentofacial parts. Therefore, establishment of equilibrium is essential for stability of treatment results

[ effect of vitamin A on orthodontic tooth movement in male rat]

It has been reported that, administration of excessive vitamin A can lead to profound effects on bone. This vitamin can induce bone degradation by stimulating the formation of mature osteoclasts from precursors. This study was designed to determine the effect of vitamin A on orthodontic tooth movement [OTM] using animal model. A total of 80 male Wister rats were included in this clinical trial. They were divided into eight equal groups. Orthodontic appliances were applied in all the eight groups to deliver an initial force of 60gr for 14 days on the first molar tooth. Six different doses of vitamin A were prepared. In addition to study groups, two control groups were considered as well. One control groups received daily intraperitoneal injections of olive oil and the other did not. Five rats were considered as normal base which received neither appliance nor injection and they were used for histological comparison with all groups. Study groups received 250, 500, 750, 1000, 1750, 2500 IU/Kg doses of vitamin A intraperitoneally each day. OTM was measured at the start and at the end of the study. Blood samples were taken from the heart, and the level of serum alkaline phosphatase was evaluated. After sacrificing the animals, cross-sections of maxilla were prepared by H and E and histological assessments were performed. The descriptive data was analyzed with SPSS version 11 and results were presented by mean and standard deviations. Group differences were analyzed by using One-way ANOVA, followed by Tukey, Kruskal-Wallis and Chi-Square tests. From the eight groups studied the highest amount of OTM was observed in the 2500 IU/Kg group and the least OTM was demonstrated in the 250 IU/Kg study group. Histological assessments showed no difference between vitamin A-treated and control groups. No difference was demonstrated between the groups when comparing the number of osteoclasts, cementoclasts, PDL width, root resorption, and serum alkaline phosphatase [P>0.05]. However significant difference was observed between normal base group and the other eight study groups. Based on the results of this study, despite reported effect of vitamin A on bone tissue, it did not accelerate alveolar bone remodeling and therefore did not change the process of orthodontic tooth movement