Effects of Tooth Coating Material and Finishing Agent on Bleached Enamel Surfaces by KTP Laser

Abstract

Objective: The purpose of this study was to evaluate the effect of tooth coating material and finishing agent on bleached enamel surfaces after using KTP laser with 27% hydrogen peroxide.

Background data: There have been few reports on the effects of tooth coating materials and finishing agents after bleaching.

Methods: After 40 crowns of human extracted maxillary incisors were bleached by KTP laser, bleached enamels were finished with fluoride only or both of fluoride and nano-hydroxyapatite as a finishing agent. After application(s) of fluoride and/or finishing agent, the enamel surfaces were divided into 2 groups, which were covered with the coating material or without coating material. After application of coating materials, all specimens were kept for 2 weeks at 37°C of 100% humidity. After removing the coating material, color changing was measured and enamel surfaces were examined by scanning electron microscopy (SEM).

Results: SEM observation of enamel surfaces treated the fluoride gel, finishing agent and coating material showed the most flattered surface compared to other groups. By measuring the color changing, few color changing was observed on the enamel surfaces treated the fluoride gel, finishing agents and coating material.

Conclusion: These results suggested that applications of fluoride gel, finishing agent and coating material made the enamel-surfaces flattered and kept effects of bleaching, could prevent the re-coloration. After applications of fluoride gel and finishing agent, covering the bleached-enamel surfaces with the coating material enhanced the keeping whiteness. It would give the patients satisfaction of whiteness.

Keywords: KTP laser; bleached enamel surface; coating material; finishing agent.

Fig. 1:

Schematic of the experimental procedure. Surface of the enamel was divided into two parts along the center line.

Fig. 2:

The color difference values (∆E*ab) between C₁ and C₂. The color variable of tooth was evaluated using a digital tooth colorimeter, ShadeEye NCC, at the labial enamel surface one-third from the cervical line. Data are the mean ± SEM from five experiments. *Values of p<0.05 were considered statistically significant.

Fig. 3:

Representative SEM photographs of the enamel surface. (A) fluoride gel, (B) fluoride gel and coating material, (C) fluoride gel and finishing agent, (D) fluoride gel, finishing agent and coating material, (E) finishing agent, (F) finishing agent and coating material, (G) control. Original magnification ×4,500; bar represents 10 μm.