Method: Ten bovine teeth were used to obtain 50 enamel specimens (5 x 5 mm) divided into 5 groups (n=10) as follows: CO - Control (non sterilized); GI - Gamma Irradiation (1.75 Gy/h for 15h); SA - Steam Autoclave (121ºC for 30 min); EO - Ethylene Oxide (EtO 30% + CO270% for 3.5h) and MI - Microwave Irradiation (3 min at 650 W). After the sterilization procedures, the specimens were coated with carbon and submitted to analysis using a scanning electron microscope equipped with an EDS detector. The system was operated at 12 kV, with magnification of 200x and counting time of 180 s. The counts were conducted in two areas for each specimen. Data from major elements identified were obtained in weight % and Ca/P ratio was also calculated. Student’s t-test and ANOVA were used for statistical analysis (α ≤ 0.05).
Result: The results indicated that the major elements detected in all samples were calcium, oxygen and phosphorus, with no statistical significant difference among groups (p > 0.05). The Ca/P ratio values (Mean ± SD) also showed no statistical significant difference, with p > 0.05, according groups: CO (2.5 ± 0.9), GI (2.5 ± 0.7), SA (2.5 ± 0.9), EO (2.4 ± 0.7) and MI (2.4 ± 0.7).
Conclusion: The results of this EDS study suggest that the sterilization methods evaluated produced no changes on the chemical composition of enamel.