Abstract

The effects of a nonthermal atmospheric plasma jet (NAPJ) on the enamel demineralization rate around orthodontic brackets were investigated. Fifty extracted caries-free human premolars were divided randomly into five groups and fixed with round wires. For each group, 100 cm3 BHI medium containing 2 glucose with 1.5 × 108 cells of Streptococcus mutans was used. Moreover, 10 cm3 of this solution was replaced with 10 cm3 of a fresh solution with glucose and S. mutans for 21 days. Group 1 held negative controls. Group 2 teeth were brushed in a tooth-brushing machine with fluoride-free toothpaste and a soft brush. Groups 3, 4, and 5 were exposed twice a week with NAPJ for 1, 2, and 3 minutes, respectively, and were brushed. Lastly, all teeth were sectioned buccolingually, and demin-eralization depth was measured by stereomicroscope. The mean demineralization depth in groups 3, 4, and 5 was less than that in group 2 (P < 0.05) and group 1 (P < 0.001). There were no significant differences among groups 3, 4, and 5 with different plasma exposure du-rations. While the demineralization depth average in groups 3, 4, and 5 was about 80 that of group 2, it was mostly about 60 that of group 1. Therefore, it was concluded that the NAPJ is a suitable tool for the reduction of cariogenic bacterial species at 1-min exposure. More-over, demineralization was not completely observed in 20 positions on the enamels in all groups. © 2022 by Begell House, Inc.