Cristiane Duque

In vitro and in vivo investigation of the biological and mechanical behaviour of resin-modified glass-ionomer cement containing chlorhexidine

OBJECTIVES To evaluate: (1) the in vitro antibacterial, cytotoxic and mechanical properties of a resin-modified glass ionomer cement (RMGIC) containing different concentrations of chlorhexidine (CHX) and (2) the in vivo microbiologic action of the best concentration of CHX associated with the RMGIC applied on remaining dentine after indirect pulp treatment (IPT). METHODS For the in vitro studies, RMGIC was associated with 0.2, 0.5, 1.25 and 2.5% CHX. Microbiologic evaluation consisted of an agar diffusion test on cariogenic bacteria for 24h. Odontoblast-like cell metabolism and morphology analyses measured the cytotoxic effects of the RMGIC groups after 24h. The same groups were submitted to compressive and diametral tensile strength. The in vivo treatment consisted of IPT using an RMGIC associated with the best CHX concentration. Clinical and microbiologic evaluations were performed before and after 3 months. RESULTS The use of 1.25% CHX significantly improved the antibacterial effects of the evaluated RMGIC, without causing any detrimental effects to the odontoblast-like cells and on the mechanical properties. This RMGIC and CHX combination completely eliminated mutans streptococci after 3 months of IPT. CONCLUSION The RMGIC and 1.25% CHX mixture showed great biological and mechanical behaviour and could be a good treatment against caries progression. CLINICAL SIGNIFICANCE The association of CHX with a liner RMGIC opens a new perspective for arresting residual caries after IPT.

Evaluation of two alternative methods for disinfection of toothbrushes and tongue scrapers.

OBJECTIVE The aim of this study was to investigate the effectiveness of two alternatives methods for the disinfection of oral cleaning devices. METHODS One type of toothbrush and two types of tongue scrapers (steel and plastic) were tested in this study. Sixteen specimens of each group were cut with standardized dimensions, contaminated separately with Candida albicans, Streptococcus mutans and Staphylococcus aureus and incubated for 24 h. After this, oral cleaning devices were washed in saline solution to remove non-adhered cells and divided into two groups (n = 8), one irradiated in microwave and other immersed in 3.78% sodium perborate solution, and evaluated for microbial recovery. The values of cfu of each group of microorganism after disinfection were compared by Kruskal-Wallis and Dunn non-parametric test, considering 95% of confidence. RESULTS The toothbrush harboured a significant larger number of viable organisms than the tongue scrapers. The steel tongue scraper was less susceptible to adhesion of the three oral microorganisms. The time required to inactivate all contaminating microorganisms using microwave oven was 1 min and, for the immersion in 3.78% sodium perborate solution, was 2 and 3 h, respectively, for C. albicans and S. mutans/S. aureus. CONCLUSION Microwave irradiation proved to be an effective alternative method to the disinfection of tongue cleaners and toothbrushes.