Surface Characteristics of Esthetic Tooth-coating Materials and Bacterial Adhesion Characteristics

Abstract

Purpose: Surface characteristics and bacterial adhesion characteristics of tooth coating materials were investigated. Methods: In this study, using 2 types of tooth-coating material with different compositions and a 3-dimensional electron probe surface roughness analyzer, the surface roughness, gloss level, antibacterial activity against cariogenic Streptococcus mutans, and adhesion characteristics of Streptococcus oralis, which is the bacterium showing initial adhesion, were investigated. The 2 types of coating material were Beauty Coat (BC, main components: S-PRG fillers, bis-GMA, TEGDMA) and White Coat (WC, main components: silica fillers, sodium fluoride, UDMA, HEMA). Based on differences in the surface treatment method, the BC group was classified into the strip-pressure group (BCA), finishing-polishing group (BCP), and resin-hardening accelerator application group (BCG), and the WC group was classified into the strip-pressure group (WCA), finishing-polishing group (WCP), and surface-lubricant application group (WCT). Result: Although no significant differences in the surface roughness were noted between the 2 types of tooth-coating material in each surface treatment method, the gloss level significantly differed in the order of BCA, WCA>BCG, WCT>BCP, WCP. No influences of 1,000 times of thermal cycling in water at 4 and 60℃ were observed. Furthermore, although the 2 types of tooth-coating material showed no antibacterial activity against S. mutans in each surface treatment method, the adhesion characteristics of S. oralis was significantly lower in BCA and BCP, in comparison with other groups. From these results, it was speculated that the capacity for bacterial adhesion to tooth-coating materials, whose surface roughness (Ra) is less than 0.1 μm and gloss level is 40-90%, is not influenced by the surface roughness or gloss level, but is influenced by the composition of tooth-coating materials, such as S-PRG fillers and sodium fluoride, in particular. Conclusion: It was suggested that, although tooth-coating material application is a temporary treatment, the restoration surface becomes smoother and glossier with each surface treatment method, and the use of tooth-coating materials considering the bacterial adhesion characteristics will be beneficial to the prognosis after surface treatment from the perspectives of esthetics and oral hygiene.