Avaliação clínica e laboratorial do uso de materiais bioativos para preservação de tecido desmineralizado

Abstract

Bioactive materials are an interesting alternative to prevent demineralization and maintenance of dental tissue, since they are able to release remineralizing ions into the environment. The aim of Chapter I was to evaluate the influence of the association of bioactive materials (45S5 and Niobiophosphate -NbG) with resin-modified glass ionomer cement (CIV-MR) regarding the alkalinizing potential, release of fluoride ions, demineralized dentin microhardness and its antimicrobial effect. Methodology: Four experimental groups composed of: RC- Composite

Resin; CIV-MR- Resin Modified Glass Ionomer Cement; 45S5- CIV-MR+10%45S5; NbG- CIV-MR+10%NbG were evaluated. The alkalinizing potential and fluoride release of the

materials were evaluated at different times, and their effect on microhardness at different depths of dentin. For microhardness, dentin slabs were used, which were subjected to caries induction, performing treatment in one half of the slab and the other half remained as a control. The antimicrobial effect of the different experimental groups was evaluated by analyzing the surfaces of materials exposed to colonies of S. mutans UA159. The two-way, three-way ANOVA and T-tests and post-hoc tests were used for the different outcomes evaluated. Results: The alkalinizing potential and fluoride release was higher for 45S5 (p = 0.000) over 60 days. At a depth of 10μm, 45S5 and NbG showed the highest microhardness values (p <0.001). Regarding acidity of the biofilm, 45S5 presented the highest pH values, and a difference was observed between the different materials and times (p = 0.000). Conclusion: The 45S5 bioactive glass associated with the CIV-MR has greater alkalinizing potential and fluoride release, over time, increasing the microhardness of demineralized dentin, and decreasing the acidity of the biofilm. The objective of Chapter II was to present a pragmatic study that proposes the evaluation of the effectiveness of the association of 45S5 with resin-modified glass ionomer cement (CIV-MR) in retaining and preventing the progression of initial carious lesions in permanent molars. Methodology: A total of 36 patients, aged 8 to 14 years, with at least two permanent molars homologous with ICDAS (International Caries Detection and Assessment System) 3 or 4 will be selected to participate in the clinical study of the split-mouth type. The DMF-T (Decayed, Missed and Filled Teeth index), ICDAS, BOP (Bleeding on probing), and VPI (Visible Plaque Index) will be analyzed. The complementary radiographic exam will be performed to assess the dentin underlying lesion. The selected teeth will be randomly assigned into 2 groups: GIC-MR and GIC-MR + 45S5. Parameters such as retention, the clinical performance of materials, and caries evolution will be evaluated into the two studied groups. A calibrated evaluator will perform clinical, radiographic, and microscopic evaluations at 1, 6, and 12 months of follow-up. The results obtained will be evaluated using the Chi-square test. The intention to treat protocol will be followed. Conclusion: The application of the 45S5 association with the GIC-MR may be a promising alternative material for the prevention of the caries lesions evolution with enamel microcavities. In Chapter III, the objective was to evaluate the retention of resin-modified glass ionomer cement (CIV-MR) associated with 45S5 bioglass and its influence in preventing the progression of moderate caries lesions in permanent molars. Methodology: From a total of 1,161 patients, 31 patients were selected and sixty-two permanent homologous molars with moderate lesions of caries, from patients aged 8 to 14 years, were randomly treated with CIV-MR or CIV-MR associated with the 45S5 bioglass. The index of decayed, missing and filled teeth (DMFT), International Caries Detection and Assessment System (ICDAS), Bleeding on probing (BOP), and Visible Plaque Index (VPI) were recorded and initial radiographic examinations were performed. After 1 month, a clinical and radiographic examination was performed, and the retention and clinical quality of the applied material were assessed. The data were analyzed using the Chi-square test of independence (χ2 = 0.05). Results: After one month, there was a difference in the degree of retention of materials (p = 0.031), with total retention predominating in the CIV-MR group. The CIV-MR showed better clinical performance (anatomical shape, marginal adaptation, superficial texture and marginal discoloration) when compared to the CIV-MR + 45S5 (p <0.05). There was a significant reduction from ICDAS 3 and 4 to ICDAS 0 (fully sealed tooth) and 3 (p <0.05), with no significant difference between groups (p = 0.053). During this period, there was an increase in BOP and VPI. Radiographically, none of the groups showed progression of caries lesions. Conclusion: The materials CIV-MR and CIV-MR + 45S5 showed favorable results in controlling the evolution of caries disease, despite the fact that bioactive materials still need improvements to obtain better retention and quality of the material.