AVALIAÇÃO IN VIVO DAS ALTERAÇÕES EM DENTINA INFECTADA DE DENTES DECÍDUOS APÓS TRATAMENTO RESTAURADOR MINIMAMENTE INVASIVO

Abstract

This study evaluated the infected dentin from deciduous teeth before and after cavity sealing, using clinical criteria (dentin color, consistency and fluorescence) and laboratorial criteria (microbiological, ultra-structural, mineral and immunohistochemical evaluations). Clinical and radiographic aspects from the treated teeth were also assessed after a mean period of 11 months in oral function. Fourty-five deciduous molars with active caries lesions and without signs or symptoms of pulp pathologies were selected. The infected dentin was divided in two portions for evaluation and removal in different moments: before cavity sealing (mesial portion) and 60 days after restoration (distal portion). Scores were used to register dentin color and consistency; dentin fluorescence was measured with DIAGNOdent 2095. Carious dentin samples were collected for microbiological analysis ( total viable counts), ultra-structural (SEM) and mineral analysis (SEM/EDS - calcium, phosphorus and fluoride) and immunohistochemical assays (expressions of MMP-2, MMP-8, MMP-9, type I collagen and bone sialoprotein [BSP]). The cavities were restored with high viscosity glass ionomer cement (GIC) and reopened after 60 days, when the same tests were done in the distal portion. After removal of the caries samples needed for the different analysis, the teeth were restored with GIC again and were clinical and radiographic followed-up. The characteristics of the restorations were evaluated using United States Public Health System criteria. Radiographic subtraction techniques in standardized radiographics allowed the detection of differences in the mineral content from the carious dentin bellow restoration over time, using the evaluation of gray levels changes. Data from dentin color, consistency, fluorescence and total viable counts were analysed using Wilcoxon signed rank test; the weight percentage of calcium, phosphorus and fluoride, and the expressions of MMP-2, MMP-8, MMP-9, collagen type I and BSP were compared using paired t test; the restorations characteristics after 10-13 follow-up period were analysed using McNemar test; the mean gray levels over time were compared using two way ANOVA (α= 0.05). Sixty days after cavity sealing, the infected dentin samples exhibited lower values of fluorescence (p<0.0001) and total viable counts (p<0.0001), as well as higher values of consistency (p<0.0001), calcium (p=0.001) and phosphorus content (p=0.002) and expressions of MMP-8 (p=0.018), type I collagen (p=0.004) and BSP (p<0.001). There were no statistical differences in dentin color, fluoride content and expressions of MMP-2 and MMP-9. Ultra-structural changes were clear: the infected dentin showed much less bacteria and better tissue organization, with narrower dentinal tubules and a more mineralized and compact intertubular dentin. After 10-13 months follow-up, the restorations were acceptable clinically, with alterations detected only for cavosurface discoloration (p=0.008), wear (p < 0.001) and surface texture (p < 0.001). The radiographic subtraction routine showed that the mean of gray levels in sound and carious dentin increased (p<0.001). It is possible to conclude that sealing infected dentin from deciduous teeth promotes tissue reorganization and favors the remineralization of remained carious dentin, in a constant process over the time.