Evaluation of dentin caries like-lesions produced by different models

Author(s)

Larissa Ferreira Pacheco

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2010-02-26

Examining board members

Regina Maria Puppin Rontani; Eliana Rodrigues

• Advisor: Regina Maria Puppin Rontani

Abstract

The use of restorative materials attached to the dentin substrate has been a challenge that has been overcome in the last years. Research has been able to improve the bonding between the materials and dentin substrate, however, the most studies use sound dentin, since the use of dentin after caries remove, such as dentin substrate affected make research difficult to perform. Among the main reasons stand the difficult selection of similar lesions, and, therefore a challenge to the researchers for the variability found in the results not reaching the proper scientific evidence for the application of bonding techniques. In order to improve the researches about this specific substrate, the aim of this study was to evaluate different models to produce caries, using the biological model, and the in situ model, comparing them about the cross-sectional microhardness and caries depth with the natural carious lesion, thus, extract teeth with caries dentin. Were used 15 third molars, including 5 teeth with natural caries (occlusal caries with average depth- CN), 10 teeth were sound, which 5 were used for the in situ production model of caries (IS) and 5 for the biological model (MB). Of all the teeth were obtained dentin samples with 4x4x2mm. Sound dentin samples were submitted to surface microhardness analysis and after to artificial caries process. After the cariogenic challenge, samples of the three groups (CN, IS, e MB) were cross sectioned to the center obtaining two sections which one was submitted cross-sectional microhardness analysis (CSMH) and the other to Scanning Electron Microscopy (SEM). Samples were analyzed as cross-section hardness in 4 columns with 8 different points (with a distance of 20µm between the first five indentations and 100µm between the last three) obtaining average measures for sample. The rest of sections were submitted to analysis by SEM to check the depth of the lesion, which was measured in the deepest region of each one. The data obtained by microhardness analysis and the depth lesion by SEM were submitted to ANOVA 2 criteria and t test, and ANOVA and Tukey test, respectively (p<0,05). Results of surface microhardness after to artificial caries process showed significantly difference between biological model and in situ model, and the biological model had no difference to natural caries. In the cross-sectional microhardness in situ model present no statistically difference from natural caries, but the lowest CSMH was observed for biological model of caries producing. SEM analysis, the artificial carious dentin lesions produced by biological model and natural carious dentin had similar depth, and the in situ model had the lowest depth of carious lesion. Based on the obtained results of this study it was concluded that both methods showed similar characteristics to natural caries dentin but concerning different tests: surface and cross-sectional microhardness, and scanning electron microscopy. (AU)

• FAPESP's process: 08/02331-6 - Study of different dentin substrata in order to bond adhesives systems. Morphological, molecular and mechanical analysis
• Grantee: Larissa Ferreira Pacheco
• Support Opportunities: Scholarships in Brazil - Master