Sérgio Luiz Pinheiro

Capacity of photodynamic therapy for microbial reduction in periodontal pockets

Practitioners are not successful in implemented treatments due to the great difficulty in completely removing bacterial deposits and their endotoxins. This study aimed to evaluate the capacity of photodynamic therapy to reduce the numbers of viable bacteria in periodontal pockets. Microbiological samples were collected before and after scaling and after photodynamic therapy. Photodynamic therapy was performed through the insertion of the photosensitizer toluidine blue and Endo PTC into the pocket for 3xa0min, followed by photosensitization with low-intensity diode of 4xa0J/cm2. The results (log10) were submitted to a descriptive analysis and a t-test. A reduction of 81.24% in the numbers of bacteria after scaling was observed, as well as 95.90% after photodynamic therapy (Pu2009<u20090.01). Photodynamic therapy is indicated as an adjuvant treatment to reduce the numbers of viable bacteria in periodontal diseases.

Effective Analysis of the Use of Peracetic Acid after Instrumentation of Root Canals Contaminated with Enterococcus faecalis

INTRODUCTIONnThe aim of this study was to evaluate the effectiveness of peracetic acid (PAA) in cleaning root canals contaminated with Enterococcus faecalis.nnnMETHODSnSixty first and second mandibular molars were used. Their mesiobuccal canals were prepared with the Reciproc System (VDW, Munich, Germany). The canals were irrigated with 10xa0mL saline during instrumentation. The teeth were randomly divided into 3 groups (nxa0=xa020), according to the irrigation solution to be used after instrumentation: group PAA (5xa0mL 1% PAA), group EDTA/sodium hypochlorite (NaOCl) (5xa0mL 17% EDTA followed by 5xa0mL 2.5% sodium hypochlorite), and group S (5xa0mL saline). Microbiological samples were collected before instrumentation and after final irrigation. Bacterial quantification was performed by counting the number of colony-forming units (CFUs/mL). The results were analyzed by the nonparametric Wilcoxon and Kruskal-Wallis tests.nnnRESULTSnThe 3 groups showed a significant reduction (Pxa0<xa0.05) in CFUs/mL after final irrigation. PAA and NaOCl associated with EDTA produced a significantly higher reduction in CFUs/mL (Pxa0<xa0.05) compared with saline. There was no statistically significant difference between PAA and EDTA + 2.5% NaOCl (Pxa0>xa0.05).nnnCONCLUSIONSnAccording to the results of the present study, the effectiveness of 1% PAA was similar to that of 17% EDTA + 2.5% NaOCl in cleaning curved root canals contaminated with E. faecalis.

Antimicrobial Capacity of Casein Phosphopeptide/Amorphous Calcium Phosphate and Enzymes in Glass Ionomer Cement in Dentin Carious Lesions

OBJECTIVEnTo evaluate the ability of casein phosphopeptide/amorphous calcium phosphate (CPP/ACP) and lysozyme, lactoferrin, and lactoperoxidase (LLL) added to glass ionomer cement (GIC) to inhibit the growth of S. mutans in a caries model.nnnMATERIAL AND METHODSnEighty permanent third molars were selected. The dentin of these teeth was exposed and flattened. Except for the coronal dentin, the specimens were waterproofed, autoclaved, and submitted to cariogenic challenge with standard strain of S. mutans. The carious lesions were sealed as follows: group 1 (n=20): GIC without additives; group 2 (n=20): GIC + CPP/ACP; group 3 (n=20): GIC + LLL; group 4 (n=20): GIC + CPP/ACP + LLL. S. mutans counts were performed before the caries were sealed (n=5), after 24 hours (n=5), at 1 month (n=5), and at 6 months (n=5). The results were analyzed using descriptive statistical analysis and the Kruskal-Wallis test (Student-Newman-Keuls test).nnnRESULTSnGIC + LLL caused a significant reduction of S. mutans 1 month after sealing (p<0.01); however, there was a significant growth of S. mutans 6 months after sealing. GIC, GIC + CPP/ACP, and GIC + CPP/ACP + LLL showed similar behavior with significant reduction of S. mutans after 24 hours (p<0.05) and increase after 1 and 6 months.nnnCONCLUSIONnThe addition of LLL to GIC increases the antimicrobial action of GIC on S. mutans. This leads to control of bacterial biofilm for 1 month, thus stopping the progression of carious lesions.

Manual and Rotary Instrumentation Ability to Reduce Enterococcus faecalis Associated with Photodynamic Therapy in Deciduous Molars

This aim of this study was to assess the ability of manual or rotary instrumentation associated with photodynamic therapy (PDT) to reduce Enterococcus faecalis using three combinations of light/photosensitizers: toluidine blue O/laser, fuchsin/halogen light and fuchsin/LED. Twenty deciduous molars were selected and contaminated with Enterococcus faecalis (McFarland 0.5 scale). Working length determination was performed by visual method. The teeth were randomly divided into two groups: G1 (n=10): manual instrumentation (Kerr-type files) and G2 (n=10): rotary instrumentation (ProTaper system). The bacteria were collected three times using sterile paper cones compatible with the anatomic diameter of the root canal for 30 s before and after instrumentation and after PDT. The samples were diluted in peptone water, seeded on blood agar plates and incubated in an oven at 37 °C for colony-forming units counting. The decrease of E. faecalis counts after instrumentation and after PDT was compared using the Wilcoxon test, t-test and Kruskal Wallis test. A significant reduction of E. faecalis occurred after manual and rotary instrumentation and after PDT using the three combinations of light/photosensitizer (p<0.05). It may be concluded that both rotary and manual instrumentation reduced E. faecalis. Fuchsin with halogen light or LED irradiation and toluidine blue O with laser irradiation can be used to reduce E. faecalis in root canals of primary molars. PDT can be used as an adjuvant to conventional endodontic treatment.

Evaluation of the furcation area permeability of deciduous molars treated by neodymium:yttrium–aluminum–garnet laser or adhesive

The purpose of this in vitro study was to compare the effects of a self-etch adhesive system and neodymium:yttrium–aluminum–garnet (Nd:YAG) laser application on the dentinal permeability of the furcation area of primary molars. After endodontic access, 39 extracted human deciduous molars were divided into three groups: control group (CG), no treatment; adhesive group (AG), self-etching adhesive was applied to the furcation area; laser group (LG), specimens were irradiated with Nd:YAG laser. To evaluate dentin permeability of the furcation area, we immersed the specimens in 0.5 % methylene blue dye for 4xa0h. Then, they were longitudinally sectioned into two halves and photographed. The images were analyzed by two qualified evaluators using TpsDig software to calculate the percentage of the dye penetration area in comparison with the total furcation area. Additional analyses by scanning electron microscopy (SEM) were performed. The analysis of variance (ANOVA), complemented by Student’s t-test, showed that mean dye penetration in the LG was statistically significant lower than that in all the other groups (Pu2009<u20090.05). The SEM analysis showed mostly dentinal tubules obliterated by smear layer in the CG; in the AG the smear layer was modified by the adhesive, and, in the LG, melted surfaces were observed. It can be concluded that the Nd:YAG laser was capable of reducing the dentinal permeability of the furcation area of deciduous molars.

Microbial contamination and inhibitory effect against Streptococcus mutans from fifth-generation bonding systems

PURPOSEnThe aim of this study was to evaluate microbial contamination and inhibitory effect against Streptococcus mutans (SM) of Prime & Bond (PB), Single Bond (SB) and Excite (EX) bonding systems before use, and after 10 and 20 applications.nnnMETHODSnThe bonding material was collected by applying a drop of the material directly on broth brain-heart infusion. The samples were homogenized, diluted and seeded on blood agar plates. To evaluate the inhibitory effect on SM, a drop of each bonding material was dispensed on filter discs and placed on blood agar plates. The Cochran statistical analysis was used to evaluate the total amount of viable bacteria among the different bonding systems. Comparisons between the inhibitory effects on SM were made using the Kruskal-Wallis test.nnnRESULTSnAdhesives SB and EX presented microbial contamination (p<0.05) and inhibitory effect (p<0.05) over SM strains with statistically significant differences concerning PB. SB and EX inhibitory capacity remained after 20 applications.nnnCONCLUSIONSnThe monomers variation in chemical composition, solvent and application technique of the bonding systems had an influence on contamination by the total number of bacteria and on the inhibitory effect on SM.

Capacity of a hydroxyapatite–lysozyme combination against Streptococcus mutans for the treatment of dentinal caries

Background: One current strategy for the treatment of carious lesions is the use of biomaterials with antimicrobial activity. Aims: The aim of this study was to evaluate a combination of hydroxyapatite and lysozyme for the treatment of dentinal caries by measuring Streptococcus mutans counts before carious tissue sealing, and 24 h, 1 month, and 6 months after treatment. Materials and Methods: Forty permanent third molars were selected, and flat dentin surfaces were prepared. The teeth were exposed to a cariogenic challenge with S. mutans. After challenge, the dentinal caries were collected from five specimens. The remaining specimens were treated with a mixture of hydroxyapatite and lysozyme in sodium laureth sulfate and sealed with composite resin. S. mutans counts were obtained 24 h, 1 month, and 6 months after sealing. Statistical Analysis: The results were evaluated by descriptive statistics and Wilcoxon signed-rank test. Results: a significant reduction in S. mutans (CFU/mL) was observed in dentinal lesions 1 month after treatment with hydroxyapatite/lysozyme in sodium laureth sulfate (P = 0.0254). Comparison of S. mutans counts obtained 24 h, 1 month, and 6 months after treatment revealed reductions only at the 1-month time point (P = 0.0318). Conclusions: the combination of hydroxyapatite and lysozyme may be an alternative for reducing the S. mutans burden in dentinal caries.

Two endodontics techniques analysis in primary molars with fistula

OBJECTIVE: The purpose of this research was to follow the radiolucent area (pixels) in the furcation area and the behavior of the endodontically treated deciduous molars with different simplified echniques.METHODS: The treatments were performed without the duct instrumentation using relative isolation and two drugs were applied, as follows: G1: Guedes-Pinto paste (GP) and G2: CTZ paste (CTZ) for the pulp chamber filling. The radiolucent areas in the furcation region of deciduous molars were obtained from previous x-rays, after 6 and 12 months of the endodontic treatment and was analysed by l Image Tool 3.0 by two blinded examiners. In order to analyse the calibration between the examiners, Kappa test was used and for comparison of the initial radiographic image, analysis of variance was used after 6 and 12 months of each group and Tukey spost-hoc test. T-Student test was used for comparison between groups.RESULTS: There was a reduction of radiolucent area after 6 (p<0.01) and 12 months (p<0.01) in the teeth treated with CTZ paste. In the teeth treated with PG there was not reduction of radiolucent area after 12 months. (p= 0,09).CONCLUSION: Although the clinical signs were similar in both groups after 12 months of follow up, only teeth treated with CTZ showed reduction of radiolucent area in the furca area after 6 and 12 months.

Microleakage analysis of dental caries lesions sealed with flow resin and compared to microhybrid resin restorations in dentin

Objective To evaluate the sealing of cavities of dentinal occlusal caries lesions, reproduced in vitro, with flow resin compared to cavity restorations presenting healthy dentin using microhybrid composite resin. Methods The sample consisted of 27 healthy deciduous molars where cavities of approximately 2 mm in the fossa region were performed and occlusal cleft of each tooth were sealed, impermeabilization was performed and the sample was randomly divided into 2 groups: group I underwent cariogenic challenge and occlusal sealing with resin flow. The teeth of group II were restored with microhybrid composite resin. The teeth were immersed in 5% methylene blue for 8 hours at 37° C and washed until all the dye was removed from the surface. The teeth were sectioned in the mesio-distal direction. The penetration of the dye was evaluated: 0no penetration; 1dye penetration up to 1/3 of the restoration; 2dye penetration up to 2/3 of the restoration depth; 3 penetration of dye into the pulp wall. The results were analyzed by the Biostat 4.0 program. Descriptive analysis and the mode among the examiners submitted to the Mann-Whitney test. Results There was no significant difference in microleakage between restoration performed in healthy dentin with microhybrid composite resin or maintenance of infected dentin in primary teeth sealed with resin flow (p = 0.6035). Conclusion It was concluded that the marginal infiltration of primary molars sealed with microhybrid composite resin and resin flow was not influenced by the removal -or not -of the carious tissue or the material used. Indexing terms: Dental caries. Dental leakage. Methylene blue. Pediatric dentistry. Tooth deciduous.

Dental acid etchant as a sensitizing agent in photodynamic therapy to reduce S. mutans in dentinal carious lesions

The study aims to assess the utility of dental acid etchant containing 37% phosphoric acid and methylene blue dye (DAE) as a sensitizing agent for photodynamic therapy (PDT) to reduce Streptococci mutans in dentinal caries. Forty-five permanent third molars were sectioned and the coronal dentin exposed. A cariogenic challenge was performed using brain-heart infusion (BHI) supplemented with 0.5% yeast extract, 1% glucose, 1% sucrose, and S. mutans ATCC 25175 standardized to 0.5 McFarland turbidity. Specimens were incubated in anaerobic jars at 37xa0°C for 15xa0days. During this period, BHI broth was renewed every 24xa0h. After 15xa0days, specimens were randomly divided into three groups (nu2009=u200915): DAE, application of dental acid etchant containing 37% phosphoric acid and methylene blue dye for 15xa0s; LLL, application of low-level laser (wavelength 660xa0nm, energy 4xa0J/cm2, power 5xa0W) for 15xa0s; and PDT, application of DAE for 15xa0s followed by LLL irradiation (660xa0nm, 4xa0J/cm2, 5xa0W). Carious tissue from each specimen was collected before and after the applications. Five decimal dilutions were performed and the resulting solution was seeded in mitis-salivarius-bacitracin agar. Plates were incubated in anaerobic jars at 37xa0°C for 48xa0h. Analysis of variance (ANOVA) with post hoc Tukey’s test was used to compare total S. mutans counts. Significant reductions in S. mutans were observed after DAE application (40.70%, pu2009<u20090.0001), LLL (12.35%, pu2009=u20090.0036), and PDT (55.22%, pu2009<u20090.0001). Dental acid etchant containing 37% phosphoric acid and methylene blue dye can be used as a photosensitizing agent for PDT to reduce S. mutans burden in dentinal caries.