Materials and method: The study used the crown portion of 10 extracted human permanent molars. Two groups were formed. In Group 1 (control) the cusp tips of the occlusal enamel surface were analyzed by ESCA twice: before the treatment and after one hour of treatment with carbamide peroxide. In Group 2 (study group) the cusp tips were analyzed three times: before storage in pooled saliva, after 24 hour storage in saliva at room temperature and after one hour treatment with 10% carbamide peroxide gel. Significance was determined using one way ANOVA with a=0.05.
Results: No statistically significant changes were found in the control group except for an increase in silicon after treatment with the carbamide peroxide gel. In Group 2, an increase in carbon and nitrogen was observed after biofilm formation, while the surface concentration of oxygen, calcium and phosphorus decreased. After one treatment with carbamide peroxide, carbon and nitrogen decreased, while oxygen, calcium, phosphorus and silicon increased. These changes were statistically significant.
Conclusion: Carbamide peroxide gel treatment of one hour increased the atomic percentage of silicon at the outermost atomic layer of the enamel. This increase may be due to the retention of silicon particles in rough parts of the outer surface of the enamel.
In Group 2 the presence of the biofilm was simultaneously indicated by the increase in carbon and nitrogen and the decrease in oxygen, calcium and phosphorus that may be obscured by biofilm formation. After treatment with carbamide peroxide, a decrease in carbon and nitrogen together with an increase in oxygen, calcium and phosphorus suggested that 10% carbamide peroxide gel helped to remove biofilm from the enamel surface.