Aim The aim of this study is to evaluate the effect of demographic, clinical, and radiographic factors on the duration of surgical extraction of impacted lower third molars. Materials and methods This retrospective study included patients who underwent surgical removal of impacted lower third molars, and the investigated factors were demographic data including age and gender, radiographic data including the impacted tooth angulation and depth of impaction and ramus relation, and clinical data including the state of eruption of the impacted teeth. These factors were evaluated for association with the duration of surgery. Descriptive statistical analysis included percentages and mean ± standard deviation (SD). Student's t-test was used to compare means between two groups, while for comparing the means among three or more groups for statistical significance, analysis of variance (ANOVA) test was used. Results Forty patients were included: 20 (50%) males and 20 (50%) females. The age range was from 17 to 37 years with a mean ± SD of 23.4 ± 5.016 years. The duration of surgery (± SD) in all the patients ranged from 10 to 40 minutes with a mean of 25.8 ± 8.56 minutes. Clinically unerupted teeth and deep ramus relationship were associated with statistically significant increase in duration of surgical extraction. Conclusion This study identifies state of eruption and ramus relation to be significant predictive factors, whereas other investigated factors, namely, age of patient, sex, angulation of teeth, and depth of impaction, were found to be not significant in determining the duration of surgery and hence, the difficulty of extraction. Clinical significance Duration of surgical extraction of impacted mandibular third molars can be considered as an indicator for difficulty of surgical extraction. Difficult surgical extraction of impacted mandibular third molars can be anticipated in clinically unerupted teeth and those with deep ramus relationship.
The necessary optimality conditions with Lagrange multipliers are studied and derived for a new class that includes the system of Caputo–Katugampola fractional derivatives to the optimal control problems with considering the end time free. The formula for the integral by parts has been proven for the left Caputo–Katugampola fractional derivative that contributes to the finding and deriving the necessary optimality conditions. Also, three special cases are obtained, including the study of the necessary optimality conditions when both the final time and the final state are fixed. According to convexity assumptions prove that necessary optimality conditions are sufficient optimality conditions.
... Show MoreDue to the wide distribution through the Iranian Plateau, especially in its western parts adjacent to Iraq’s northeastern borders, the occurrence of Brandt’s Hedgehog