RESUMO
OBJECTIVES: This study aimed to assess the bite force of 3-6-year-old children in primary dentition period after unilateral extraction of a primary first molar (D) and its correlation with the height, weight, gender, type of occlusion, and temporomandibular disorders (TMDs). MATERIALS AND METHODS: Twenty children between the ages of 3 and 6 years with a unilaterally extracted D comprised our case group, and 29 age-matched children with no extracted teeth comprised the control group. The maximum bite force at the site of posterior teeth was measured using a bite force measuring device with a 0.2-mm thickness and 3-cm diameter, attached to a strain-gage sensor. Each child bit the sensor with maximum force for 3 seconds, and this was repeated three times at 10-minute intervals. The mean value was calculated. Data were analyzed using SPSS 18 software program via generalized estimating equation (GEE). RESULTS: the bite force on the side of extraction was significantly lower than that on the contralateral side (P<0.05). Also, the bite force was significantly correlated with the height, gender, and age, but the correlations between the bite force and weight, type of occlusion and side of the jaw were not significant (P>0.05). CONCLUSIONS: Extraction of primary first molars decreases the bite force on the respective side of the jaw.
RESUMO
BACKGROUND: Attempts to enhance bond strength of the sealant have been among the most important sides of dental research. AIM: The purpose of the present study was to evaluate the effect of using different rinsing angles on the micro-tensile bond strength of the sealant to the etched enamel. SETTINGS AND DESIGN: Experimental study. MATERIALS AND METHODS: Sixty first-premolars were randomly assigned to six groups based on the rinsing angle applied (15°, 30°, 45°, 60°, 75°, and 90°). Following etching and rinsing, a 4-mm height build up of sealant material was created. Bonded specimens were sectioned into sticks (1 × 1 mm), which were subjected to micro-tensile bond strength, testing at a cross-head speed of 0.5 mm/min. STATISTICAL ANALYSIS USED: The data were analyzed by Kolmogorov-Smirnov and post-hoc Tukey test. RESULTS: The tensile bond strength in specimens rinsed at 90° were statistically higher compared to those rinsed at 15° and 30° (P < 0.05), and increasing the angle from 15° to 90° was correlated with a reduction in the number of specimens with adhesive failures. CONCLUSIONS: Rinsing the conditioned enamel surface at 90° may improve the bond strength and retention of the sealant.
