Validação de modelo de ciclagens de pH para avaliar o efeito de dentifrícios fluoretados na desmineralização do esmalte de dente decíduo humano

Author(s)

Marilia Mattar de Amoêdo Campos Velo

• Document type: Master's Dissertation
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2014-06-25

Examining board members

Cinthia Pereira Machado Tabchoury; Fausto Medeiros Mendes; Marinês Nobre dos Santos

• Advisor: Cinthia Pereira Machado Tabchoury

Abstract

The effect of fluoridated toothpaste on dental caries prevention in primary dentition is concentration-dependent. However, there is no pH-cycling model validated to assess the dose-response to fluoride (F) in human primary teeth enamel. Thus, this study validated a pH-cycling model in terms of dose-response to F to evaluate primary teeth enamel demineralization, and later, the model was tested with commercial toothpastes with different F concentrations. Two independent studies were conducted and primary teeth enamel slabs (3 X 3 X 2 mm), selected according to the surface hardness, were used in both. To validate the model, dental slabs (n=12/group) were submitted to the pH-cycling model and treated twice a day with: purified water (negative control) and solutions containing 62.5; 125; 250 and 375 ?g F/mL. These F concentrations were chosen to simulate the dilution (1:3 w/w) that occurs in the oral cavity when dentifrices containing 250, 500, 1000 and 1500 ?g F/g, respectively, are used. The model lasted 10 days and the slabs remained daily for 6 h in a demineralizing solution and 18 h in a remineralizing solution at 37°C. After validation, the model was tested with commercial toothpastes and enamel slabs (n=15/group) were treated with: no F toothpaste, 500 ?g F/g, as low F toothpaste, 1100 and 1450 ?g F/g, as standard toothpastes. The percentage of surface microhardness loss (%SMHL) and the carious lesion area (?S) were determined. The dose-response effect to F was analyzed by quadratic regression and the toothpaste effect by Tukey¿s test. The model showed dose-response relationship between F concentration and %SMHL (R²=0.7047; p<0.01) and ?S (R²=0.4465; p<0.01). When the pH-cycling model was used to evaluate the anticaries potential of commercial toothpastes, the mean (±SD) of %SMHL and ?S for the group treated with 500 ?g F/g was 36.6±8.0 and 6298.5±1221.3, respectively, which were significantly higher than those treated with 1100 (25.2±8.7 and 4565.7±1122) and 1450 ?g F/g toothpastes (24.2±5.2 and 2339.1±879.7), respectively. In conclusion, this validated model is able to differentiate the anticaries potential of toothpaste with low F concentration (500 ?g F/g) from those with standard concentrations (1000-1500 ?g F/g) (AU)

• FAPESP's process: 12/03105-5 - Validation of pH cycling model to estimate the potential of fluoridated products in reducing deciduous enamel demineralization
• Grantee: Marilia Mattar de Amoêdo Campos Velo
• Support Opportunities: Scholarships in Brazil - Master