Evaluation of Dentin Tubule Occlusion Using Pre-Treatment with No-Ozone Cold Plasma: An In Vitro Study

Abstract

Dentin hypersensitivity is a common disease of the oral cavity, which renders the tooth extremely sensitive to stimuli. These symptoms usually result from the exposure of the dentinal tubules to the external environment. There is a need for a treatment for dentinal hypersensitivity that can overcome the shortcomings of the existing agents. This study thus aimed to assess the therapeutic efficacy of no-ozone cold plasma (NCP), which was developed for safe use in the oral cavity, in conjunction with 1.23% acidulated phosphate fluoride (APF) and hydroxyapatite (HA), which are widely used conventional treatments of hypersensitivity. The fluoride content was evaluated using electron probe micro-analyzer (EPMA) analysis. Moreover, we confirmed the effect of NCP pre-treatment on the dentinal tubule occlusion by APF and HA as follows: scanning electron microscopy and energy dispersive X-ray spectrometry were employed to analyze the exposed dentinal tubules, and the calcium and phosphorus content were measured. Furthermore, an additional experiment was conducted using a metal mesh to analyze the working elements of NCP. All experimental results were analyzed by one-way analysis of variance and then by using the Turkey test as a post hoc test. EPMA analysis confirmed that the fluoride content of the APF and NCP group was significantly higher than that of the APF group (p < 0.001). The fluoride content of the group treated with APF and NCP equipped with a metal mesh was significantly lower than that in the group treated with APF and NCP and the group treated with APF and NCP equipped with a cotton mesh (p < 0.01). Moreover, the group treated with NCP pre-treated with HA and APF exhibited significantly greater dentinal tubule occlusion than the other groups (p < 0.05). The same result was confirmed by calculating the calcium/phosphorus ratio (p < 0.05). Pre-treatment of the enamel and dentin surfaces with plasma improved hypersensitivity by enhancing fluoride deposition with APF and dentinal tubule occlusion with HA.