Influence of the acquired pellicle and the moment of application of the AmF/NaF/SnCl2 solution in the prevention of in situ erosion in human enamel

Author(s)

Camila Vieira da Silva

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia (FO/SDO)
• Defense date: 2019-08-20

Examining board members

Patricia Moreira de Freitas Costa e Silva; Taís Scaramucci Forlin; Heitor Marques Honório; Cecilia Pedroso Turssi

• Advisor: Patricia Moreira de Freitas Costa e Silva

Abstract

Considering that the protective ability of the salivary acquired pellicle under dental erosion can be influenced by several factors, and that the characteristics of the present pellicle can modify the deposition of salts on the surface of the dental enamel, it is possible that the salivary acquired pellicle can influence the effectiveness of the solution of AmF/NaF/SnCl2 against erosion. The first stage of this study, in vitro, aimed to obtain a simplified protocol for the formation of erosive lesion in human dental enamel, varying acid concentration, frequency and duration of erosions. For this, 64 samples of human dental enamel were divided into 8 experimental groups (n = 8), according to the proposed cycling: G1 - 0.5% citric acid, 3x/day, 2 min; G2 - 0.5% citric acid, 6x/day, 2 min; G3 - 0.5% citric acid, 3x/day, 5 min; G4 - 0.5% citric acid, 6x/day, 5 min; G5 - citric acid 1%, 3x/day, 2 min; G6 - citric acid 1%, 6x/day, 2 min; G7 - citric acid 1%, 3x/day, 5 min; G8 - citric acid 1%, 6x/day, 5 min. The response variable was the loss of mineral tissue (in ?m) by means of optical profilometry. One-way ANOVA showed that there was a statistical difference between the groups, and Tukey showed that only G2 and G3 were similar and all the other groups differed from each other. Thus, the cycling considered simpler, similar to G7, was chosen for the stage in situ, adding erosive immersion to the protocol. The second stage of the study, in situ, was designed to assess whether the acquired pellicle and moment of application interfere with the action of AmF/NaF/SnCl2 solution in erosion control. Twelve volunteers were required for this 3-phase, randomized, split-mouth, cross-over model. Six treatment protocols were tested using human enamel samples in replicas: G1 - without treatment, with the presence of acquired pellicle; G2 - without treatment, without acquired pellicle; G3 - AmF/NaF/SnCl2 solution prior to the first daily acid immersion, with acquired pellicle; G4 - AmF/NaF/SnCl2 solution prior to the first daily acid immersion, without acquired pellicle; G5 - AmF/NaF/SnCl2 solution after the first daily acid immersion, with acquired pellicle; G6 - AmF/NaF/SnCl2 solution after the first daily acid immersion, without acquired pellicle. Erosive challenges (1.0% citric acid, pH 2.3, 4x5 min/day) and removal of the acquired pellicle (2% Sodium Dodecyl Sulfate) were performed extra-orally, while mouthwash was applied intraorally (30 sec). Tissue loss were determined by optical profilometry (n=12) and morphological changes were evaluated by scanning electron microscopy (n=3) analysis. Data were statistically analysed by two-way ANOVA for randomized blocks, with subsequent pairwise comparison of treatments. No significant interaction between the independent variables \"Type of Treatment\" and \"Acquired Pellicle\" was found (p=0.211). Considering the main factor \"Type of Treatment\", when compared to the group without treatment, enamel loss was statistically significant lower with application of tin solution (p<0.001), regardless of whether it was applied either before or after erosive cycling, whether in presence or absence of pellicle. Therefore, neither the presence of acquired pellicle, nor the moment of application, influences the anti-erosive ability of the AmF/NaF/SnCl2 solution in the present model. (AU)

• FAPESP's process: 16/08524-7 - Influence of adquired pellicle and timing of application of the AmF/NaF/SnCl2 solution on its potential to control the progression of human enamel erosion.
• Grantee: Camila Vieira da Silva
• Support Opportunities: Scholarships in Brazil - Doctorate