Evaluation of the protective effect of TiF4 gel, associated or not with CO2 laser (10.6 µm) irradiation with low fluence on eroded bovine dental enamel: in vitro study

• Grant number: 16/21517-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2016
• End date: November 30, 2017
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Patricia Moreira de Freitas Costa e Silva
• Grantee: Juliane de Paula Tavares
• Host Institution: Faculdade de Odontologia (FO). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Several measures have been proposed for controlling dental erosion, as the use of fluoridated products and lasers. This study aims to evaluate the effect of different fluoridated gels on the progression of erosive lesion in dental enamel and the possible influence of CO2 laser combination (10.6 µm) with low energy density (fluence), for these treatments. Therefore, this study will have two experimental stages. In stage I, 80 previously eroded enamel fragments will be randomly divided into 8 groups (n=10): G1 - negative control (no treatment); G2 - placebo gel (water + thickener); G3 - 2% NaF gel (pH 7.0); G4 - 2% NaF gel (pH 1.5); G5 - 5.42% NaF gel (pH 7.0); G6 - 5.42% NaF gel (pH 1.5); G7 - 4% TiF4 gel (pH 1.5) and G8 - 4% gel TiF4 (pH 7.0). After treatments, samples will be subjected to 10 days of erosive cycling by alternating immersions in citric acid solution (0.05 M, pH 2.3, 2 min, 6x/day) and artificial saliva. After applying the gel, 5 and 10 days of cycling, profilometric analyzes will be performed (surface loss in µm). For stage II, 40 previously eroded enamel slabs will be randomly divided into four experimental groups (n=10): G1 - no treatment (negative control); G2 - application of the gel that provides the best results in stage I (positive control); G3 - CO2 laser irradiation and G4 - CO2 Laser irradiation + gel with the best results of stage I. Irradiations will be performed with a CO2 pulsed laser (10.6 µm, 0.4 W, 50 Hz, 5.7 J/cm2, 10 ms, 10 mm from the tooth surface in focused mode). Samples will be subjected to 10 days of erosive cycling and analyzed by optical profilometry (n=10) as in stage I. In addition, three randomly selected samples from each group will be evaluated in scanning electron microscopy (n=3) to determine possible changes caused in the enamel surface morphology. Surface loss results from both stages will be subjected to homogeneity and normality tests to determine the most appropriate statistical test (significance level=5%). (AU)