Aim:
To evaluate enamel microhardness and morphology after bleaching with hydrogen peroxide containing calcium in different concentrations.
Methods:
One hundred specimens of human teeth were ground and polished and had the initial microhardness evaluated. The specimens were randomly assigned into five groups (n=20): Group 1 - Control group (no treatment); Group 2 - Home Peroxide 6% (without calcium); Group 3 - Home Peroxide 7.5% (without calcium); Group 4 - White Class 6% (with calcium); Group 5 - White Class 7.5% (with calcium). For each group, the bleaching was performed according to the manufacturer's specifications. The specimens were bleached once a day for 5 days and subjected to pH cycling. Microhardness and scanning electron microscopy (SEM) analysis were performed before and after bleaching.
Results:
The results showed that groups submitted to bleaching treatment presented hardness loss compared to the control group. The group of 7.5% hydrogen peroxide with calcium showed a lower percentage of hardness loss in relation to other groups.
Conclusion:
Calcium in association with a higher hydrogen peroxide concentration may decrease microhardness changes on enamel.
bleaching agents; calcium; hydrogen peroxide; dental enamel
