Photodynamic antimicrobial therapy (PACT) promotes bacterial death as a result of the photosensitization of microbial components. This study evaluated the effect of PACT on dentine caries produced in situ. Over the course of 14 d, 20 volunteers wore intra-oral devices containing human dentine slabs that were treated 10 times daily with a 40% sucrose solution. Afterwards, the antimicrobial effect of toluidine blue O, associated with 47 or 94 J cm(-2) of a light-emitting diode, was evaluated. Before and after the treatments, dentine samples were analysed with regard to the total number of microorganisms, total streptococci, mutans streptococci, and lactobacilli. Significant reductions in the bacterial count were observed for PACT with both energy densities tested, with the following values observed for 47 and 94 J cm(-2) of irradiation: for total streptococci, 3.45 and 5.18; for mutans streptococci, 3.08 and 4.16; for lactobacilli, 3.24 and 4.66; and for total microorganisms, 4.29 and 5.43, respectively. The control, treated with 94 J cm(-2) of irradiation alone, was also effective against all bacteria. To conclude, PACT was effective in killing oral microorganisms present in dentine caries produced in situ and may be a useful technique for eliminating bacteria from dentine carious lesions before restoration.

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The development of a method to ensure bacterial free substrates without extensive cavity prepa ration would be highly useful to dentistry, since there is no currently available effective method for killing residual bacteria in dentinal tissue. This randomized in vitro study determined parameters for using toluidine blue O (TBO) with a light emitting diode (LED) for dentine caries disinfection and monitored intrapul pal/periodontal temperatures during irradiation. Occlusal human dentine slabs were immersed in Streptococ cus mutans culture for demineralization induction. Slabs were allocated to 10 groups (n = 15), which were treated with 0.1 mg ml-1 TBO with 5 min of incubation time or 0.9% NaCl solution for 5, 10 or 15 min, and submitted or not to irradiation for 5, 10 or 15 min (47, 94, and 144 J/cm 2). Before and after treatments, den tine samples were analyzed with regard to S. mutans counts. In whole teeth, temperature in pulp and peri odontium was measured by thermocouples during irradiation. Kruskal Wallis/Student Newman Keuls, and ANOVA/Tukey test were respectively utilized to compare log reductions and temperature rises between groups. Bacterial reduction was observed when dentine was exposed to both TBO and LED at all irradiation times, as well as to LED alone for 10 and 15 min. Temperature increases lower than 2°C were observed for either pulp or periodontium. Concluding, LED combined with TBO is a safe and effective approach for den tine caries disinfection. Nevertheless, additional studies should be conducted to determine the influence of the irradiation in S. mutans viability in dentinal surface/tubules.

Aim:The aim of this study was to evaluate a very short-term in vitro and in situ effect of 2% chlorhexidine-digluconate-based (CHX) cavity cleanser on the disinfection of dentin demineralized by cariogenic bacteria.Materials and Methods:Human dentin slabs were randomly allocated and used in 2 distinct phases, in vitro and in situ, for obtaining demineralized dentin. In vitro, the slabs (n=15) were immersed for 5 days in BHI broth inoculated with Streptococcus mutans CTT 3440. In situ, a double-blind design was conducted in one phase of 14 days, during which 20 volunteers wore palatal devices containing two human dental dentin slabs. On 5th day in vitro and 14th day in situ, the slabs were allocated to the two groups: Control group (5 μl of 0.9% NaCl solution) and CHX group (5 μl of 2% chlorhexidine digluconate solution, Cavity Cleanser™ BISCO, Schaumburg, IL, EUA), for 5 minutes. The microbiological analyses were performed immediately before and after the treatments.Results:The log reductions means found for CHX treatment on tested micro organisms were higher when compared to Control group either in vitro or in situ conditions.Conclusions:Our results showed that CHX was effective in reducing the cultivable microbiota in contaminated dentin. Furthermore, although the use of chlorhexidine-digluconate-based cavity disinfectant did not completely eliminate the viable microorganisms, it served as a suitable agent to disinfect tooth preparations.

Autotransplantation is a safe and currently common procedure in cases of agenesis and tooth loss. Autotransplantation of premolars to replace missing maxillary central incisors has been shown to be an excellent treatment choice, especially in young patients in the 9-12-year-old age range. The choice for adequate restorative materials and techniques is also essential, direct composite resin being indicated in most cases. This paper reports the case of two premolars autotransplanted to replace both maxillary central incisors and addresses the esthetic issues involved in the reshaping of these teeth to incisor morphology.