SURFACE MICROHARDNESS OF DIFFERENT RESTORATIVE MATERIALS EXPOSED TO CANDIDA ALBICANS BIOFILM ISOLATED FROM THE ORAL CAVITY OF HIV-INFECTED CHILDREN

Abstract

Introduction: Candida albicans is one of the microrganisms that most often colonizes the oral cavity of HIV-infected children. This fungus secretes organic acids, which decrease the pH of the oral cavity; an environment that is already particularly acidic in HIV-Infected children because of their hypercaloric diets, use of sugary medicines, and poor oral hygiene. Considering the large number of dental restorations and the high prevalence of caries in this population, these conditions, including the metabolism of C. albicans, can potentially cause problems in terms of the surface of restorative materials. Objective: Therefore, the aim of this study was to evaluate, in vitro, the potential of C. albicans isolated from the dental biofilm of HIV-infected children to cause surface demineralization of the restorative materials used in pediatric dentistry. Material and method: Forty-four blocks of four different materials (2 resins, 1 compomer, and 1 glass ionomer cement) were made and separated into four groups (n = 11). All blocks were submitted to initial surface microhardness (ISM) analysis. Subsequently, each block was exposed to C. albicans biofilm, formed from a 1 mL standard suspension containing 105 yeasts/mL, over seven days. The blocks were then cleaned and kept at 4 °C until being submitted for measurement of the final surface microhardness (FSM). The Mann-Whitney test was used for intragroup comparisons between ISM and FSM values. Results: The percentage of microhardness loss (% MHL) values between the four groups were compared using the Kruskall- Wallis test (95% CI). The ISM values ranged from 63.54 ± 11.41 to 77.92 ± 10.91, with no statistical differences being found (p = 0.76). After exposure to biofilm, no significant changes in surface microhardness were observed when comparing the values of ISM and FSM, except for group 3 (compomer VitremerTM), which had an FSM value of 40.45 ± 7.57 (p = 0.001). The % MHL of the compomer (group 3) was significantly higher (41.16%) than the other groups (5.35% group 1; 7.02% group 2; and 9.57% group 3) (p = 0.036). Conclusion: It can be concluded that, in vitro, C. albicans isolated from the dental biofilms of HIV-infected children can cause   significant reduction in the surface microhardness of compomer compared with other materials.