Comparison of heat generation during implant drilling using stainless steel and ceramic drills.

PURPOSE: The purpose of this study was to compare the heat generated from implant drilling using stainless steel and ceramic drills. MATERIALS AND METHODS: A total of 40 fresh bovine femoral cortical bone samples were used in this study. A constant drill load of 2.0 kg was applied throughout the drilling procedures via a drilling rig at a speed of 1,500 rpm. Two different implant drill types (stainless steel and ceramic) were evaluated. Heat was measured with type K thermocouple from 3 different depths. Data were subjected to the independent-sample t test and Pearson correlation analysis. The α level was set a priori at 0.05. RESULTS: The mean maximum temperatures at the depths of 3 mm, 6 mm, and 9 mm with the stainless steel drill were 32.15°C, 35.94°C, and 37.05°C, respectively, and those with the ceramic drill were 34.49°C, 36.73°C, and 36.52°C, respectively. A statistically significant difference was found at the depth of 3 mm (P = .014) whereas there was no significant difference at the depths of 6 and 9 mm (P > .05) between stainless steel and ceramic drills. CONCLUSION: Within the limitations of the study, although more heat was generated in the superficial part of the drilling cavity with the ceramic drill, heat modifications seemed not to be correlated with the drill type, whether stainless steel or ceramic, in the deep aspect of the cavity. Further clinical studies are required to determine the effect of drill type on heat generation.

The effect of unilateral partial edentulism to muscle thickness.

OBJECTIVE: Teeth and muscles play a very important role for occlusal equilibrium and function. When tooth loss begins, it may also affect the function of the muscle tissues. METHODS: The thickness of the masseter and anterior temporalis muscles were measured bilaterally in 30 healthy fully dentate adults and in 30 unilateral edentulous patients by using ultrasonographic imaging. All scans were carried out by the same radiologist to eliminate the inter-observer difference, using a real time scanner (Toshiba SSA- 270 A Japan). A 7.5 MHz linear transducer was used. The transducer was held against the cheek with light pressure. The effect of age, sex, duration of the partial edentulism, unilateral chewing habits of the individuals to the muscle thickness were also evaluated. In all subjects, facial proportion index was also determined. RESULTS: No study has been found in the literature concerning the masticatory muscle thickness in unilateral partial edentulous patients. Therefore, the main purpose of this study was to compare and establish the differences of the muscle thicknesses between dentate and edentulous sides in unilateral partial edentulous patients with ultrasonography and to test whether the variation in the thickness of the muscle is related to the variation in the facial morphology using the facial proportional indices in the study groups. In the present study, ultrasonography revealed a large variation in the thicknesses of the masseter and temporalis muscles in experimental and control groups, during both relaxed and contracted conditions. The thicknesses of the muscles in females during both relaxed and contracted conditions were less than those in males in both control and experimental groups. In experimental group, a high negative correlation was found between the thickness of the masseter muscle and Facial proportion Index (FPI) in females, however, the statistical analysis showed no significant difference in males. Also, a high negative correlation was found in control group, especially in females. There was no statistically significant relationship between thicknesses of the muscles and age of the subjects in both groups. There was no statistically significant relationship between unilateral chewing habits and muscle thickness. In this study, the duration of partial edentulism did not affect the thickness of the muscles. CONCLUSION: Further research is required to study muscular atrophy for comparison with total edentulism.