Effect of experimental coating with sodium fluoride and stannous chloride on erosive tooth wear

Author(s)

Sávio José Cardoso Bezerra

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia (FO/SDO)
• Defense date: 2020-02-07

Examining board members

Taís Scaramucci Forlin; Ana Cecilia Corrêa Aranha; Alessandra Buhler Borges; Anderson Takeo Hara

• Advisor: Taís Scaramucci Forlin

Abstract

The aims of this study were: 1. To formulate a hybrid coating and test its effect against enamel and dentin erosion and erosion-abrasion; 2. To modify the hybrid coating with the addition of fluoride and stannous, encapsulated or not, and thereafter test their effects against erosion and erosion-abrasion. The retention of the hybrid film to the dental substrate was evaluated by Scanning Electron Microscopy (SEM). Then, sodium fluoride (15,000 ppm F) or sodium fluoride plus tin chloride (10,000 ppm Sn) were added on the polymeric film. The addition of the agents was performed by direct or encapsulated means. The amounts of fluorine and tin chloride released by the nanocapsules (halloysite and bentonite, respectively), in acidic (citric acid 0.3%, pH=2.6) and neutral media, were evaluated by an ion selective electrode and atomic emission spectrometry, respectively, 1, 3, 5, 12, 24 and 48 h after immersion. Then, the enamel and dentin specimens, obtained from bovine incisors, were subjected to the treatments and tested in erosion and erosion-abrasion cycling models (n = 10 for each substrate, for each model). Deionized water was used as a negative control and a fluoride varnish (Fluor Protector, 1000 ppm F-) was used as positive control. Erosive cycling consisted of 5 min of immersion in 0.3% citric acid (pH = 2.6), followed by 60 min of remineralization in artificial saliva, 4 times a day for 5 consecutive days. For the erosion-abrasion cycling, the same protocol was used, however, the specimens were brushed on a brushing machine after the first and last erosive challenges with a fluoridated toothpaste and water slurry (1:3) for 15 sec (45 strokes), with 2 min total suspension exposure. At the end of the cycling, the tooth surface loss (in µm) was evaluated by optical profilometry. Data were analyzed by Kruskall-Wallis, Dunn and Mann-Whitney tests (?=0.05). The SEM analysis showed the presence of the hybrid coating as a film over the dental substrates. The clays were able to store the antierosive agents, presenting a greater release of F- and Sn2+ in acid medium in relation to the neutral one, at all times. For enamel, in the erosion model, the hybrid coating and positive control showed significantly less SL than negative control (p<0.05), without difference between them (p=1). The other groups did not significantly differ from the negative control (p>0.05). For dentin, all the hybrid coatings tested and the positive control showed significantly less surface loss than the negative control (p <0.05), except the groups hybrid coating with encapsulated fluoride and hybrid coating with fluoride and stannous, which did not differ from each other (p> 0.05). For the erosion-abrasion model, none of the groups showed significantly lower SL than negative control, for both substrates. The hybrid coating was able to adhere to dental substrate and protect them from erosion, regardless of the addition of the agents. However, none of the treatments tested was effective on protection of erosive tooth wear on enamel and dentin. (AU)

• FAPESP's process: 17/13855-5 - Anti-erosive and anti-abrasive effect of a hybrid film associated or not with sodium fluoride or sodium fluoride and stannous chloride in enamel and dentin
• Grantee: Sávio José Cardoso Bezerra
• Support Opportunities: Scholarships in Brazil - Doctorate