Effect of type of artificial bovine enamel caries lesion on the remineralizing potential of Saliva, fluoride dentifrice and varnish: an in situ study

Author(s)

Priscila Maria Aranda Salomão

• Document type: Master's Dissertation
• Press: Bauru.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Bauru (FOB/SDB)
• Defense date: 2013-08-28

Examining board members

Ana Carolina Magalhães; Alberto Carlos Botazzo Delbem; Linda Wang

• Advisor: Ana Carolina Magalhães

Abstract

This study evaluated the effect of type of artificial enamel carious lesion produced by four in vitro protocols in respect to the remineralizing potential in situ, using as response variables: surface microhardness (SH), cross-sectional microhardness (CSH) and transverse microradiography (TMR). Thus, 288 polished enamel specimens (4x4mm) were divided according to the baseline SH values in 4 demineralizing protocols: MC gel (8% methylcellulose gel, 0.1 M lactic acid, pH 4.6, 14 days); PA gel (20g/L polyacrylic acid, 0.1 M lactic acid with 500 mg/L hydroxyapatite, pH 4.8, 16h); MHDP solution (50 mM lactic acid, calcium, phosphate and tetraethyl methylene diphosphanate, pH 5.0, 6 days) and Buffer Solution (50 mM acetic acid, calcium, phosphate and fluoride, pH 5.0, 16h). The demineralized specimens were treated with the remineralizing agents in an in situ model, with crossover and double-blind design. Twelve volunteers wore intra-oral appliances containing two specimens of each type of enamel lesion in each phase, during 3 experimental phases with duration of 3 days each. In the phase \"human saliva\", the volunteers performed the treatment of specimens with placebo toothpaste (no fluoride, solution 1:3) ex vivo, 2x1min/day. In phase \"fluoride toothpaste\", the same procedure was repeated, but using the toothpaste Crest (1100 ppm F). In the phase \"fluoride varnish\", the same procedures of the phase \"fluoride toothpaste\" were repeated, but the specimens were treated with Duraphat varnish (22600 ppm F, 6h in vitro) prior to the in situ phase. The data were submitted to statistical analysis (ANOVA or similar nonparametric test and 2-way ANOVA, p<0.05). The different demineralizing protocols produced artificial carious lesions with different profiles (similar results among SH, CSH and TMR. Degree of demineralization: MHDP solution> MC Gel > Buffer solution = PA Gel). There was a clear difference in the degree of remineralization between the different artificial carious lesions (contradictories results among SH, CSH and TMR). In SH analysis, PA Gel was able to show significant differences among the 3 remineralizing protocols, while MC Gel and Buffer Solution showed significant differences between the fluoride phases and control. MHDP solution did not show any significant difference among the remineralizing treatments. In respect to the CSH, remineralization was inversely related to the degree of initial demineralization. In the analysis of the percentage of CSH recovery, only PA gel was able to show significant differences between the fluoride and control phases up to 30 &#x3BC;m depth. For TMR (&#x394;&#x394;Z parameter), there was significant difference between the artificial carious lesions in respect to the remineralization (buffer solution < MHDP Solution = PA gel < MC Gel), except during fluoride varnish phase. No significant differences were found among the remineralizing treatments by TMR, showing a modest remineralization, regardless of the treatment. It can be concluded that the type of artificial carious lesion has influence on the degree of enamel remineralization and this should be considered in experimental design. (AU)

• FAPESP's process: 11/03907-1 - Effect of type of artificial bovine enamel caries lesion in the remineralizing potential of saliva, fluoride dentifrice and varnish: an in situ study
• Grantee: Priscila Maria Aranda Salomão
• Support Opportunities: Scholarships in Brazil - Master