Fluorescence image and microbiological analysis of biofilm retained around healthy and inflamed orthodontic miniscrews.

INTRODUCTION: Peri-miniscrew inflammation is one of the causes of orthodontic miniscrew failure. OBJECTIVE: The aim of this study was to correlate and quantify throughout autofluorescence images, PCR and microbiologic count of biofilm retained around orthodontic miniscrew and the presence of Porphyromonas gingivalis. MATERIALS AND METHODS: Forty miniscrews used for orthodontic treatment were evaluated during orthodontic treatment, collected from patients and divided into two groups: healthy and inflamed miniscrews. To be considered inflamed, the samples should present: loss of stability checked by periotest®, clinical presence of mucositis, red aspect of the gum or bleeding around the miniscrew. Immediately after removal of the miniscrews, they were photographed using a macro 100 lens and a Pentax camera coupled to a fluorescent equipment - Qscan (AioBio - Korea) with 405 nm excitation wavelength and a blue band filter. A microbiologic sample was collected with a sterile microbrush scrubbed around the miniscrew tread. Fluorescent images were analyzed with ImageJ software to quantify fluorescent intensity and fluorescent area and microbiological samples were submitted to CFU count for total contamination and q-PCR assay to quantify Porphyromonas gingivalis. RESULTS: The results showed a good correlation between CFU count and fluorescent intensity and PCR/fluorescent area. The healthy miniscrews presented less fluorescent intensity and lower CFU count when compared to inflamed miniscrews. q-PCR analysis showed a higher number of P. gingivalis contamination around inflamed miniscrews. CONCLUSION: Quantification of biofilm retained by miniscrew by images of autofluorescence is a simple and reliable method with great potential for clinical use to monitory inflammation around miniscrew and risk of loss.

Real-time evaluation of two light delivery systems for photodynamic disinfection of Candida albicans biofilm in curved root canals.

Antimicrobial photodynamic therapy (APDT) combined with endodontic treatment has been recognized as an alternative approach to complement conventional root canal disinfection methods on bacterial biofilms. We developed an in  vitro model of bioluminescent Candida albicans biofilm inside curved dental root canals and investigated the microbial reduction produced when different light delivery methods are employed. Each light delivery method was evaluated in respect to the light distribution provided inside curved root canals. After conventional endodontic preparation, teeth were sterilized before canals were contaminated by a bioluminescent strain of C. albicans (CEC789). Methylene blue (90 µM) was introduced into the canals and then irradiated (λ = 660 nm, P = 100 mW, beam diameter = 2 mm) with laser tip either in contact with pulp chamber or within the canal using an optical diffuser fiber. Light distribution was evaluated by CCD camera, and microbial reduction was monitored through bioluminescence imaging. Our findings demonstrated that the bioluminescent C. albicans biofilm model had good reproducibility and uniformity. Light distribution in dental tissue was markedly dependent on the light delivery system, and this strategy was directly related to microbial destruction. Both light delivery systems performed significant fungal inactivation. However, when irradiation was performed with optical diffuser fiber, microbial burden reduction was nearly 100 times more effective. Bioluminescence is an interesting real-time analysis to endodontic C. albicans biofilm inactivation. APDT showed to be an effective way to inactivate C. albicans biofilms. Diffuser fibers provided optimized light distribution inside curved root canals and significantly increased APDT efficiency.