In vitro Assessment of Thermal Changes in Human Teeth during Photodynamic Antimicrobial Chemotherapy Performed with Red Light Sources

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Photo-disinfection of deep dentin caries lesions may be a useful tool for preserving tooth structure. However, increase of pulpal temperature higher than 5.5 degrees C may put pulp vitality in danger. Objectives: This in vitro study evaluated thermal effects of radiation of the red spectrum (lambda = 600-700 nm, 94 J cm(-2)) on pulpal and periodontal areas when irradiating deep dentin cavities in human teeth. Methods: Tooth preparation was performed at occlusal surface in 10 human teeth, which were irradiated by five different light units, four diode GaAlAs lasers: Coherent (C); Kondortech (B); Whitening lase (W); and K5000 with 2 different tips (K1 and K2), as well as one light emitting diode Laserbeam (LED). After application of toluidine blue O dye in the cavity, variation of temperature was measured in duplicate using a digital thermometer and 2 K-type thermocouples one placed inside the pulpal chamber and the other on root surface at the cementoenamel junction, simultaneously. The mean average temperature rise (Delta T) was calculated for each group. Results: Delta T values were analyzed by ANOVA and Tukey tests. Pulpal temperature increase ranged from 0.62 +/- 0.51 to 1.25 +/- 0.50 degrees C. Group C presented the highest Delta T, which was statistically significant different from B, K1, and K2. The lowest Delta T value was found for group K2, which statistically differed from the group W. No other statistically significant difference was found. At the root surface, Delta T values were lower than 0.5 degrees C for all devices and no statistically significantly difference was found among them. Conclusion: With regard to thermal side effects, the use of these red light sources operating at 94 J cm(-2) may be considered harmless for dental tissues.20614751480Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [620160/2006-3

Susceptibility of Streptococcus mutans biofilms to photodynamic therapy: an in vitro study

Objectives: The purpose of this study was to evaluate the antimicrobial effect of toluidine blue 0 (TBO), in combination with either a helium/neon (HeNe) laser or a light-emitting diode (LED), on the viability and architecture of Streptococcus mutans biofilms. Methods: Biofilms were grown on hydroxyapatite discs in a constant depth film ferment or fed with artificial saliva that was supplemented with 2% sucrose four times a day, thus producing a typical 'Stephan pH curve'. Photodynamic therapy was subsequently carried out on biofilms of various ages with light from either the HeNe laser or LED using energy densities of between 49 and 294 J/cm(2). Results: Significant decreases in the viability of S. mutansbiofilms were only observed when biofilms were exposed to both TBO and light, when reductions in viability of up to 99.99% were observed with both light sources. Overall, the results showed that the bactericidal effect was light dose-dependent and that older biofilms were less susceptible to photodynamic therapy. Confocal laser scanning microscopy images suggested that lethal photosensitization occurred predominantly in the outermost layers of the biofilms. Conclusions: Photodynamic therapy may be a useful approach in the treatment of dental plaque-related diseases.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.56232433

Root instrumentation with an erbium : yttrium-aluminum-garnet laser: Effect on the morphology of fibroblasts

Objective: The purpose of this study was to evaluate the effect of erbium:yttrium-aluminum-garnet laser instrumentation of root surfaces on the morphology of fibroblasts from continuous lineage. Method and materials: Dentinal slices with 4 mm(2) of surface area were obtained from teeth extracted for severe periodontal involvement. Specimens were assigned to one of three treatment groups: group 1, application of the laser with an energy level of 250 mJ at 103 pulses per second; group 2, application of the laser with an energy level of 80 mJ at 166 pulses per second; and group 3, similar to group 2, but with concomitant water irrigation of the device. The specimens were incubated in multiwell plates containing cell culture media. After 24 hours, the specimens were submitted to routine preparation for scanning electron microscopy. Three independent and blind examiners used photomicrographs to evaluate the morphology of the fibroblasts: 0 = without cells; 1 = flat cells; 2 = round cells; and 3 = combination of round and flat cells. Results: Statistical analysis indicated that there were significant differences among treatment groups and that group 3 was significantly different from groups 1 and 2. Conclusion: There was no difference between groups 1 and 2 in the morphology of fibroblasts. Laser instrumentation with concomitant irrigation impaired the adhesion of fibroblasts to dentinal surfaces.33749650

Root instrumentation with an erbium : yttrium-aluminum-garnet laser: Effect on the morphology of fibroblasts

Objective: the purpose of this study was to evaluate the effect of erbium:yttrium-aluminum-garnet laser instrumentation of root surfaces on the morphology of fibroblasts from continuous lineage. Method and materials: Dentinal slices with 4 mm(2) of surface area were obtained from teeth extracted for severe periodontal involvement. Specimens were assigned to one of three treatment groups: group 1, application of the laser with an energy level of 250 mJ at 103 pulses per second; group 2, application of the laser with an energy level of 80 mJ at 166 pulses per second; and group 3, similar to group 2, but with concomitant water irrigation of the device. The specimens were incubated in multiwell plates containing cell culture media. After 24 hours, the specimens were submitted to routine preparation for scanning electron microscopy. Three independent and blind examiners used photomicrographs to evaluate the morphology of the fibroblasts: 0 = without cells; 1 = flat cells; 2 = round cells; and 3 = combination of round and flat cells. Results: Statistical analysis indicated that there were significant differences among treatment groups and that group 3 was significantly different from groups 1 and 2. Conclusion: There was no difference between groups 1 and 2 in the morphology of fibroblasts. Laser instrumentation with concomitant irrigation impaired the adhesion of fibroblasts to dentinal surfaces

Photosensitization of in vitro biofilms by toluidine blue O combined with a light-emitting diode

In natural ecosystems, micro-organisms grow preferentially attached to surfaces, forming matrix-enclosed biofilms. The aim of this study was to determine photodestruction levels in biofilms after subjecting them to photodynamic therapy. Biofilms of Streptococcus mutans, S. sobrinus, and S. sanguinis were grown on enamel slabs for 3, 5 or 7 d. Both the number of viable micro-organisms and the concentration of water-insoluble polysaccharides were analysed, and mineral loss (Delta Z) analyses were performed on the enamel slabs. The antimicrobial potential of toluidine blue O (0.1 mg ml(-1)), associated with 85.7 J cm(-2) of a light-emission diode, was evaluated on the viability of 5-d biofilms. Both the number of micro-organisms and the concentration of water-insoluble polysaccharide increased with the age of the biofilms. A significant reduction (approximate to 95%) in viability was observed for S. mutans and S. sobrinus biofilms following photosensitization, with a > 99.9% reduction in the viability of S. sanguinis biofilms. In conclusion, a biofilm model was shown to be suitable for studying changes in bacterial numbers and enamel mineralization and for demonstrating the potential value of photosensitization in the control of in vitro biofilms.1141646

Full-Mouth Ultrasonic Debridement Associated With Amoxicillin and Metronidazole in the Treatment of Severe Chronic Periodontitis

Background: The purpose of this study was to evaluate the adjunctive clinical, microbiologic, and immunologic effects of the systemic administration of amoxicillin and metronidazole in the full-mouth ultrasonic debridement of patients with severe chronic periodontitis. Methods: Twenty-five patients presenting at least eight teeth with probing depth (PD) 5 mm and bleeding on probing (BOP) were selected and randomly assigned to full-mouth ultrasonic debridement + placebo (control group) or full-mouth ultrasonic debridement + amoxicillin and metronidazole (test group). The clinical outcomes evaluated were visible plaque index, BOP, position of the gingival margin, relative attachment level (RAL), and PD. Real-time polymerase chain reaction (PCR) was used for quantitative analysis of Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), Porphyromonas gingivalis, and Tannerella forsythia (previously T forsythensis). The enzyme-linked immunosorbent assay (ELISA) technique permitted the detection of prostaglandin E(2), interleukin-1 beta, and interferon-gamma levels in gingival crevicular fluid. All parameters were evaluated at baseline and at 3 and 6 months post-treatment. Results: At 6 months, the test treatment resulted in lower BOP and an additional reduction (0.83 mm) in PD (P= 2 mm at 43.52% of sites in control patients compared to 58.03% of sites in test patients (P= 5 mm exhibiting RAL gain >= 2 mm in the test group. Nevertheless, no improvement in the microbiologic or immunologic outcome was observed with the adjunctive use of systemic amoxicillin and metronidazole. J Periodontol 2009,80:7254-1264.80812541264Sao Paulo State, Sao Paulo, SP, Brazil [04/13256-4]Sao Paulo State, Sao Paulo, SP, Brazil [04/13256-4

Evaluation of the antimicrobial effect of photodynamic antimicrobial therapy in an in situ model of dentine caries

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)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.1175568574Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CNPq [620160/2006-3

In Vitro Photodynamic Antimicrobial Chemotherapy in Dentine Contaminated by Cariogenic Bacteria

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The development of a method to ensure bacterial-free substrates without extensive cavity preparation 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 intrapulpal/periodontal temperatures during irradiation. Occlusal human dentine slabs were immersed in Streptococcus 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, dentine samples were analyzed with regard to S. mutans counts. In whole teeth, temperature in pulp and periodontium 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 degrees C were observed for either pulp or periodontium. Concluding, LED combined with TBO is a safe and effective approach for dentine caries disinfection. Nevertheless, additional studies should be conducted to determine the influence of the irradiation in S. mutans viability in dentinal surface/tubules.20615041513Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [620160/2006-3, 564387/2008-8