Filling Material Bond Strength to Dentin Is Positively Influenced by the Agitation of Endodontic Final Irrigating Solutions.

Introduction: The final step of irrigation has been considered to of increase the bonding strength of filling material to dentin. This study investigated the impact of three final-step irrigation methods on the endodontic sealer bond strength to dentin by using a micro push-out test. Materials and Methods: Palatal roots of human maxillary molars were cleaned and shaped and randomly divided in six groups (n=15) according to the final-step irrigation method and the type of root canal sealer used. The solutions used for the final-step irrigation were 17% ethylenediaminetetraacetic acid and 2.5% sodium hypochlorite, which underwent three methods: 1) syringe-needle irrigation/conventional, 2) passive ultrasonic irrigation, and 3) XP-endo Finisher agitation. The root canal sealers used were: EndoSequence BC Sealer, and AH-Plus sealer. Roots were obturated with the single cone technique and then, cross-sectioned in 2-mm-thick slices (3 slices from each root). Push-out test was performed on the sliced specimens (cervical, middle, and apical thirds) with a universal testing machine. Bond strength values were recorded in megapascal (MPa). Subsequently, each specimen was longitudinally split to verify the type of failure. Data analysis was performed using Johnson transformation, three-way analysis of variance, Tukey's post-hoc tests, and the partial Eta squared test. Results: There were significant differences in bond strength between the sealers [AH: 4.46±2.24 and BC: 3.47±2.19 MPa (P<0.001)]; between final-step irrigation methods [passive ultrasonic irrigation: 4.52±2.25, XP-endo Finisher: 3.93±3.93 and syringe-needle irrigation/conventional: 3.37±2.51 MPa (P<0.001)], and between the root canal thirds represented by the sliced specimens [cervical: 5.45±2.39, middle: 4.14±1.99 and apical: 2.30±1.30 MPa (P<0.001)]. The interaction between the variables had no significance (P>0.05). Conclusion: Agitation of the final irrigating solution may improve the bonding of the sealer to canal walls. AH-Plus sealer had the highest bond strength. The bond strength reduced significantly towards the apical third.

Tissue repair capacity of bioceramic endodontic sealers in rat subcutaneous tissue.

This study aimed to evaluate the tissue repair capacity of four bioceramic endodontic sealers by quantifying type I and III collagen fibers. The following sealers were tested: EndoSequence BC Sealer (Brasseler, Brasseler, Savannah, USA), Bio C Sealer (Angelus, Londrina, Brazil), Bioroot RCS (Septodont, Santa Catarina, Brazil), and Sealer Plus BC (MKLife, Porto Alegre, Brazil). Polyethylene tubes 1.5 mm in diameter and 1 cm in length containing the endodontic sealers were implanted in the subcutaneous tissue of five rats (Rattus norvegicus albinus, Wistar lineage). After 14 days, the animals were euthanized, and collagen fibers were quantified from the histological tissue sections. Given a non-normal distribution of the data, a gamma regression with log link function was employed and implemented through the generalized linear models module, was used to test whether there was a significant difference between the sealers. The pairwise comparison was performed using Least significant difference. There were significant differences between the sealers for type I (p=0.001), type III (p=0.023), and total collagen (p=0.002). Overall, Bioroot sealer was statistically superior to the other sealers, except in the analysis of type III collagen, in which there was no difference between the Bioroot sealer and Bio C Sealer sealer and the control group (p>0.05). Bioroot RCS bioceramic endodontic sealer stimulates a greater production of collagen.

Tissue repair capacity of bioceramic endodontic sealers in rat subcutaneous tissue

Abstract This study aimed to evaluate the tissue repair capacity of four bioceramic endodontic sealers by quantifying type I and III collagen fibers. The following sealers were tested: EndoSequence BC Sealer (Brasseler, Brasseler, Savannah, USA), Bio C Sealer (Angelus, Londrina, Brazil), Bioroot RCS (Septodont, Santa Catarina, Brazil), and Sealer Plus BC (MKLife, Porto Alegre, Brazil). Polyethylene tubes 1.5 mm in diameter and 1 cm in length containing the endodontic sealers were implanted in the subcutaneous tissue of five rats (Rattus norvegicus albinus, Wistar lineage). After 14 days, the animals were euthanized, and collagen fibers were quantified from the histological tissue sections. Given a non-normal distribution of the data, a gamma regression with log link function was employed and implemented through the generalized linear models module, was used to test whether there was a significant difference between the sealers. The pairwise comparison was performed using Least significant difference. There were significant differences between the sealers for type I (p=0.001), type III (p=0.023), and total collagen (p=0.002). Overall, Bioroot sealer was statistically superior to the other sealers, except in the analysis of type III collagen, in which there was no difference between the Bioroot sealer and Bio C Sealer sealer and the control group (p>0.05). Bioroot RCS bioceramic endodontic sealer stimulates a greater production of collagen.

Resumo Este estudo visou avaliar a capacidade de reparação de tecidos de quatro cimentos endodônticos biocerâmicos através da quantificação de fibras colágenas de tipo I e III. Foram testados os seguintes cimentos: EndoSequence BC Sealer (Brasseler, Brasseler, Savannah, EUA), Bio C Sealer (Angelus, Londrina, Brasil), Bioroot RCS (Septodont, Santa Catarina, Brasil), e Sealer Plus BC (MKLife, Porto Alegre, Brasil). Foram implantados tubos de polietileno de 1,5 mm de diâmetro e 1 cm de comprimento contendo os cimentos endodônticos no tecido subcutâneo de cinco ratos (Rattus norvegicus albinus, linhagem Wistar). Após 14 dias, os animais foram eutanasiados e as fibras colágenas foram quantificadas a partir de cortes histológicos do tecido. Diante de uma distribuição não-normal dos dados, uma regressão gama com função de ligação log, implementada por meio do módulo de modelos lineares generalizados, foi empregada para testar se havia diferença significativa entre os cimentos. A comparação dois a dois foi realizada utilizando Least significant difference. Houve diferença significativa entre os cimentos para os colágenos tipo I (p=0,001), tipo III (p=0,023) e colágeno total (p=0,002). No geral, o cimento Bioroot foi estatisticamente superior aos demais cimentos, com exceção na análise do colágeno tipo III na qual não houve diferença entre o cimento Bioroot e o cimento Bio C Sealer e o grupo controle (p>0,05). O cimento endodôntico biocerâmico Bioroot RCS foi capaz de estimular uma maior produção de colágeno.

One-year follow-up of microscopical and clinical behavior of bioactive self-etching resin sealant.

Background: The development of early carious lesions can be prevented with the use of sealants. This study aimed to evaluate the retention and sealant quality of conventional and bioactive self-etching sealants by direct (clinical) and indirect (microscopical) assessment. Materials and Methods: Sixty newly erupted mandibular second molars (International Caries Detection and Assessment System ≤2) from adolescents were selected for the split-mouth trial study. The tooth was randomized and treated with conventional Fluoroshield (FS) and BeautiSealant (BS) bioactive self-etching sealants. Molds were taken and cast with epoxy resin after treatment. Indirect and direct assessments of retention degree and sealant remnant quality were performed after baseline, 1 month, and 1 year. The Chi-square test, ordinal regression, reasons of chance, and Fleiss' kappa statistical test were employed. Results: After 1 month, greater total retention was observed for FS, but 1-year follow-up demonstrated no retention difference for FS and BS. The odds ratios showed an 86% greater chance of FS showing better marginal adaptation, after 1 month. At 1 year, the clinical assessment showed better anatomical shape and marginal adaptation scores for FS, but no microscopical difference was observed. A pour agreement between clinical and microscopical data was observed. Conclusions: The 1-year follow-up showed no significant difference in the degree of retention, and in the microscopic evaluation of the conventional sealant (FS) and the bioactive self-etching sealant (BS), but in the clinical evaluation, better marginal and anatomical adaptation scores for FS were observed.

Effect of Bioactive Filler Addition on the Mechanical and Biological Properties of Resin-Modified Glass Ionomer.

The maintenance of affected dentin can promote the greater conservation of tooth structure. The development of materials that have properties capable of reducing the demineralizing potential and/or even helping in dental remineralization is important for conservative dentistry. This study aimed to evaluate, in vitro, the alkalizing potential, fluoride as well as calcium ion release ability, antimicrobial activity, and dentin remineralization properties of resin-modified glass ionomer cement (RMGIC) incorporated with a bioactive filler (niobium phosphate (NbG) and bioglass (45S5)). The study samples were grouped into RMGIC, NbG, and 45S5. The materials' alkalizing potential, ability to release calcium as well as fluoride ions, and antimicrobial properties concerning Streptococcus mutans UA159 biofilms were analyzed. The remineralization potential was evaluated using the Knoop microhardness test, which was performed at different depths. The alkalizing and fluoride release potential was higher for the 45S5 group (p < 0.001) over time. An increase in the microhardness of demineralized dentin was observed in the 45S5 and NbG groups (p < 0.001). No differences in biofilm formation were observed between the bioactive materials, although 45S5 exhibited lower biofilm acidogenicity at different time points (p < 0.001) and greater calcium ion release in the microbial environment. A resin-modified glass ionomer cement enriched with bioactive glasses, particularly 45S5, is a promising alternative for the treatment of demineralized dentin.

O método de fotopolimerização é capaz de influenciar nos valores de microdureza das resinas compostas? Um estudo in vitro / Is the photopolimerization method able to influence on the microhardness values of composite resins? An in vitro study

Introdução: a inovação dos métodos de fotopolimerização foi proposta na tentativa de diminuir o estresse de contração de polimerização das resinas compostas e proporcionar maior conforto ao paciente, reduzindo o tempo de atendimento odontológico. Objetivo: avaliar a microdureza de duas resinas compostas nanoparticuladas submetidas a diferentes técnicas de polimerização. Material e método: quarenta espécimes foram divididos em quatro grupos (n=10) da seguinte forma: Filtek Z350 XT® + técnica imediata (GI); Filtek One Bulkfill® + técnica imediata (GII); Filtek Z350 XT® + técnica de pulso tardio (GIII); Filtek One Bulkfill® + técnica de pulso tardio (GIV). Após o armazenamento em água destilada à temperatura ambiente, os corpos de prova foram direcionados para a medição de microdureza. Utilizou-se teste T para comparação de técnicas e teste Two-Way ANOVA para calcular os efeitos das resinas compostas, técnicas de polimerização e interações referentes à variável dependente (p ≤0,05). Resultado: a resina Filtek Z350 XT® apresentou maior dureza na técnica imediata (GI - 312,45 ± 64,37) e pulso tardio (GIII - 244,50 ± 75,63) comparado à resina Filtek One Bulkfill®, em ambas as técnicas. Observaram-se maiores valores de dureza referentes à técnica imediata, com diferença estatística significativa em relação à resina testada (p = 0,04 - Filtek Z350 XT®; p = 0,03 - Filtek One Bulkfill®). Ambos os fatores isolados (resina e técnicas) apresentaram efeito nos valores de microdureza (p = 0,02 e p < 0,01, respectivamente). Conclusão: a técnica convencional demonstrou atingir maiores valores de dureza quando comparada à técnica de polimerização alternativa.

Introduction: the innovation of photopolymerization methods was proposed in an attempt to reduce the polymerization shrinkage stress of composite resins and also provide more comfort to patient reducing the chair time. The aim of this in vitro study was to assess the microhardness of two nanofilled composite resins subject to different curing techniques. Objective: assess the microhardness of two nanofilled composite resins subject to different curing techniques. Material and method: forty specimens were divided into four groups (N=10) as follows: Filtek Z350 XT® + immediate technique (GI); Filtek One Bulkfill® + immediate technique (GII); Filtek Z350 XT® + delayed pulse technique (GIII); Filtek One Bulkfill® + delayed pulse technique (GIV). After storage in distilled water at room temperature the specimens were assessed for microhardness measurement. T-test was used for comparison of techniques and two-way ANOVA used to calculate the effects of composite resins, curing techniques and their interactions on dependent variable (p set at 0.05). Result: Filtek Z350 XT® resin presented greater hardness on immediate technique (GI - 312,45 ± 64.37) and delayed pulse (GIII - 244,50 ± 75.63) compared to Filtek One Bulkfill® under both techniques. Overall, it was observed greater hardness values under immediate technique with a significant statistical difference apart of tested resin (p = 0.04 - Filtek Z350 XT®; p = 0.03 - Filtek One Bulkfill®). Both isolated factors (resin and techniques) presented effect on microhardness values (p = 0.02 and p < 0.01, respectively). Conclusion: the conventional technique demonstrated to reach higher hardness values when compared to the alternative polymerization technique

Ex vivo evaluation of the effectiveness of XP-endo Finisher on the removal of smear layer from the root canal / Avaliação ex vivo da eficácia do XP-endo Finisher na remoção de smear layer do canal radicular

ABSTRACT Objective: The aim of this study was to evaluate the effectiveness of XP-endo Finisher (XP) on removal of the smear layer in root canals by comparing different irrigation protocols. Methods: Seventy-two human single-rooted teeth were similarly instrumented using R25 Reciproc files (VDW, Munich, Germany) applied in reciprocating mode with a VDW GOLD endo motor (VDW, Munich, Germany). The working length was determined at 1 mm short of the apical foramen. The canals were irrigated with 5 mL of 2.5% sodium hypochlorite during instrumentation. The teeth were divided at random into six groups (n=12). A control group, which was not submitted to the final irrigation protocol, and five experimental groups with different irrigants and agitation techniques: EDTA/File, EDTA/XP, EDTA/Passive Ultrasonic Irrigation (PUI), Distilled Water (DW)/XP, and DW/PUI). Smear layer removal quality scores were assessed in the apical, middle, and cervical thirds of the root canal based on images obtained by scanning electron microscopy. Data were analyzed using the Kruskal-Wallis test, followed by two-by-two comparisons with the Dunn test (α=5%). Results: EDTA/File, EDTA/PUI, and EDTA/XP groups demonstrated significantly lower scores than the other groups (P<0.05) in all thirds evaluated. No significant difference was observed between the groups in which distilled water was used and the control group in all thirds evaluated (P> 0.05). Conclusion: The XP-endo Finisher file did not increase the efficiency of EDTA in removal of the smear layer in root canals.

RESUMO Objective: Avaliar a eficácia do XP-endo Finisher (XP) na remoção da smear layer em canais radiculares, comparando diferentes protocolos de irrigação. Métodos: Setenta e dois dentes humanos unirradiculares foram similarmente instrumentados usando limas R25 (VDW, Munich, Germany) aplicadas no modo reciprocrantes em um motor endodôntico VDW GOLD (VDW, Munich, Germany). O comprimento de trabalho foi determinado a 1 mm aquém do forame apical. Os canais foram irrigados com 5 mL de hipoclorito de sódio 2,5% durante a instrumentação. Os dentes foram divididos aleatoriamente em seis grupos (n=12). Um grupo controle, que não foi submetido ao protocolo final de irrigação, e cinco grupos experimentais com diferentes irrigantes e técnicas de agitação: EDTA/Lima, EDTA/XP, EDTA/Irrigação Ultrassônica Passiva (IUP), Água destilada (AD)/XP, e AD/IUP). Os escores de qualidade de remoção da camada de smear layer foram avaliados nos terços apical, médio e cervical do canal radicular com base em imagens obtidas por microscopia eletrônica de varredura. Os dados foram analisados pelo teste de Kruskal-Wallis, seguido de comparações dois a dois pelo teste de Dunn (α = 5%). Resultados: Os grupos EDTA/lima, EDTA/PUI e EDTA/XP demonstraram escores significativamente menores que os outros grupos (P <0,05). Não foi observada diferença entre os grupos que utilizaram água destilada e o grupo controle em todos os terços avaliados (P> 0.05). Conclusão: A lima XP-endo Finisher não aumentou a eficiência do EDTA na remoção da smear layer em canais radiculares.

Influence of the geometry of the screwdriver-screw connection on the reverse torque of UCLA screws.

The aim of this study was to evaluate the influence of the geometry of the screwdriver-screw connection on the reverse torque of UCLA screws after repeated cycles of tightening and loosening in an implant-supported prosthesis. Thirty sets of external hex titanium implants, UCLA abutments, and UCLA abutment screws were divided into 3 experimental groups (n = 10). In the square group, the implant and UCLA abutment system were mounted in an upright position using a screw with a square screwdriver-screw connection. In the hexagonal group, the implant and UCLA abutment system were mounted in an upright position using a screw with a hexagonal screwdriver-screw connection. In the hexalobular group, the implant and UCLA abutment system were mounted at 70° using a dynamic UCLA abutment and screw with a hexalobular screwdriver-screw connection. Ten alternating torque-reverse torque cycles were applied to each screw using a screwdriver fixed at the end of a digital torque meter. The screws with a square connection resulted in less loss of reverse torque than the other types. Screws with a hexagonal connection showed a statistically significant loss of torque initially but remained constant for the remaining cycles. For the screws with a hexalobular connection, the loss of torque was greater, and substantial deformation of the plastic in the microstructure was noted. The screwdriver-screw connection geometry had a direct influence on the reverse torque of UCLA screws, and the initial reverse torque of the abutment screws with a square connection was greater than that of the hexagonal and hexalobular designs.

Clinical effects of the exposure to red wine during at-home bleaching.

OBJECTIVES: This clinical trial evaluated the effects of red wine exposure on the effectiveness of at-home bleaching with 10% carbamide peroxide, degree of tooth sensitivity, and levels of periodontal inflammatory markers. METHOD AND MATERIALS: Eighty participants were assigned to two groups, namely, those who drank red wine (experimental group), and those who did not drink red wine (control group). The experimental group participants rinsed their mouths with 25 mL of red wine four times a day during the bleaching period. Shade evaluation was assessed visually by using the Vita Classical and Vita Easyshade techniques. Tooth sensitivity was evaluated by the numeric and visual analog scales, and the salivary and gingival crevicular fluids were collected for assessment of nitric oxide (NO) levels, a marker of inflammation. Differences in color change were analyzed by one-way analysis of variance (ANOVA). The absolute risks of tooth sensitivity were compared by the Fisher exact test. Tooth sensitivity intensity data sets for both the visual analog scale and the numeric rating scale were compared using the Wilcoxon signed rank test (α = .05). Repeated measures and two-way ANOVA followed by the Bonferroni test were used to assess time-course and differences between groups in NO production. RESULTS: The bleaching technique was effective regardless of wine consumption (P > .05). Tooth sensitivity was classified as mild, with no differences between groups (P > .05). Red wine reduced both the gingival crevicular fluid and salivary levels of NO (P < .05). CONCLUSION: Red wine does not interfere with the effectiveness and sensitivity of at-home teeth bleaching with 10% carbamide peroxide and protects against bleaching-induced inflammation.

Pattern of Disinfection of Root Canal Dentin by Alternated Acid-Base Irrigating Regimen.

OBJECTIVE: To quantify Enterococcus faecalis density in root canal dentin after chemomechanical preparation (CMP) using alternated irrigating regimen. METHODOLOGY: Root canals (RC) were contaminated with E. faecalis (ATCC 19433) for 3 weeks and evident biofilms were obtained. After initial sampling (S1), the CMP was aided by irrigants: saline solution (control; n=12), a conventional regimen (CR) (group 1; n=12) using 5.25% NaOCl and a final rinse with 17% EDTA, and an alternating regimen (AR) of intercalated use of NaOCl and EDTA (group 2, n=12), followed by a second sampling (S2). After 2 weeks, S3 was obtained. Two roots were analyzed by scanning electron microscopy. Each root was divided into cervical, mild, and apical segments and sampling of the superficial (n=90) and deep (n=90) dentin layers was obtained using Gates-Glidden burs. The E. faecalis density (CFU/mg) in log10 was categorized as residual (0 > 0.2), moderate (0.2 ≥ 0.5), or elevated (> 0.5). The prevalence of positive samples in BHI and BHI-A was analyzed by Pearson's chi-square test. The data were normalized by a log10 transformation of CFU and were analyzed by one-way ANOVA and Tukey's tests. RESULTS: Biofilms were observed only in the control root canal walls. Topographically, the controls and CR showed similar distributions of E. faecalis in the dentin. Microbiologically positive root canals harbored much E. faecalis in the adjacent dentin (p < 0.05). Irrigating saline provided moderate density of E. faecalis in the dentin while CR and AR resulted in a residual density of microorganisms (p < 0.05). CONCLUSIONS: The Enterococcus faecalis density in dentin was influenced by the irrigating regimen and the microbiological status of the root canal. The CMP aided by the alternating regimen interfered with the recolonization of the root canal and topographic distribution of Enterococcus in root dentin.

Effects of Exposure to Cola-Based Soft Drink on Bleaching Effectiveness and Tooth Sensitivity of In-Office Bleaching: A Blind Clinical Trial.

OBJECTIVE: The purpose of this single-blind (evaluators) and parallel design study was to evaluate whether exposure to a cola-based soft drink during bleaching treatment with 35% hydrogen peroxide (HP) affects color change and bleaching-induced tooth sensitivity. MATERIAL AND METHODS: Forty-four patients with central incisors darker than A2 were selected. Participants who did not drink cola-based soft drinks were assigned to the control group (CG), while participants who drank a cola-based soft drink at least twice a day were assigned to the experimental group (EG). For the CG, foods with staining dyes were restricted. For the EG, there was no restriction on food and patients were asked to rinse their mouths with a cola-based soft drink for 30 s, 4 times daily. For both groups, 2 sessions with three 15 min applications of 35% HP were performed. Shade evaluation was assessed via subjective (VITA classical and VITA bleacheguide shade guides) and objective methods (Easyshade spectrophotometer) at baseline, during bleaching (first, second, and third weeks), and post bleaching (1 week and 1 month). Patients recorded their sensitivity perceptions using a numerical rating scale and 0-10 visual analog scales. Variation in shade guide units and the 2 colors (DE) were evaluated with a Student's t-test (α = 0.05) and Mann-Whitney test (α = 0.05). Absolute risk of tooth sensitivity and intensity of tooth sensitivity were evaluated by a Chi-square test (α=0.05). RESULTS: Effective bleaching was observed for both groups after 30 days, without statistical difference (p > 0.08). There was no significant difference in absolute risk of bleaching-induced tooth sensitivity between the 2 groups (p = 0.74). Higher and significant scores in pain scales were detected for the EG in comparison to the CG (p < 0.05). CONCLUSION: Even that the cola-based soft drink exposure during in-office bleaching treatments did not affect the bleaching's effectiveness; patients reported a higher intensity in bleaching-induced tooth sensitivity.

Correlation between the Periapical Index and Lesion Volume in Cone-beam Computed Tomography Images.

INTRODUCTION: The study aimed to correlate the Periapical Index (PAI), obtained by way of periapical radiographs, with the volume of chronic periapical lesion, obtained through cone-beam computed tomography (CBCT), in the permanent teeth. METHODS AND MATERIALS: Radiographs and CBCT images were selected from 35 single-rooted permanent teeth, with fully formed apices, with a diagnosis of pulp necrosis and chronic apical periodontitis that was radiographically visible. Two independent raters evaluated the radiographs on two separate occasions and classified the periapical lesions in accordance with Ørstavik's PAI. The periapical lesion volume was calculated in the CBCT images. The correlation between the PAI and the lesion volume was calculated using Spearman's correlation test. RESULTS: There was a positive, moderate correlation between the PAI and the volume (rs=0.596; P<0.001) where rs2 is equal to 0.355, showing that only 35% of the PAI variation was dependent upon the variation in periapical lesion volume. CONCLUSION: The radiographic evaluation of the periapical lesion does not reflect the lesion's volumetric characteristics as the volume had a moderate effect on the choice of PAI score.

Exploring different photodynamic therapy parameters to optimize elimination of Enterococcus faecalis in planktonic form.

BACKGROUND: The failure of endodontic treatment is linked to the presence of Enterococcus faecalis in the root canals. The scope of this study was to evaluate the influence of the energy dose and frequency of photodynamic therapy (PDT cycles), as well as the volume of bacterial suspensions (BS) in the elimination of Enterococcus faecalis in planktonic form. METHODS: In four successive assays BS of Enterococcus faecalis ATCC 19433 were irradiated with a diode laser (40 mW) using the photosensitizer (PS) methylene blue (MB) (0.005 µg/mL). Group 1 - Effect of energy dose: 100 µâ€¯L of BS and 100 µâ€¯L of PS were irradiated by 1, 2.5, 5, 7.5 and 10 minute s. Group 2 - Effect of PDT cycles: The BS received 1, 2, 3 or 4 PDT cycles (in each cycle 100 m L of PS was added and irradiated by 2.5 minutes). Group 3 - Effect of energy dose and bacterial suspension volume: 10 µâ€¯L of BS and 10 µâ€¯L of PS were irradiated similar to group 1. Group 4 - Effect of energy dose, bacterial suspension volume and PDT cycles: 10 µâ€¯L of BS and 10 µL of PS were irradiated according to group 2. The laser source and MB isolated represented the controls. RESULTS: The mean log reduction after separate applying laser light and MB were 0.01 and 0.07, respectively. It was found that wells with 100 µâ€¯L of BS irradiated with 2.4 to 24 J of energy did not cause significant bacterial elimination (p > 0.05), on the other hand PDT cycles above 12 J increased significantly bacterial elimination (p < 0.05). In 10 µâ€¯L wells irradiation from 12 J of energy provided higher bacterial elimination (p < 0.05) which combined with PDT cycle resulted in the logarithmic elimination of E. faecalis (p < 0.05). CONCLUSIONS: The energy dose, the volume of the bacterial suspension and, especially, the PDT cycles optimized the bacterial elimination of Enterococcus faecalis in planktonic form.

Effect of different endodontic sealers and time of cementation on push-out bond strength of fiber posts.

OBJECTIVES: This study aims to evaluate the effect of different endodontic sealers (epoxy resin, eugenol, and bioceramic/calcium silicate-based) and the time of cementation (immediately or 7 days after canal obturation) on the bond strength of a fiberglass post cemented with RelyX™ ARC. MATERIAL AND METHODS: Eighty-four premolars were instrumented and divided into groups (n = 12) according to the sealer and the time of post cementation: Endofill (EN), Endosequence BC Sealer (BC), and AH Plus (AH) had immediately fiber post cementation; EN7, BC7, and AH7 had post cementation after 7 days; and control group (C) had fiber post cementation without endodontic sealer. Each post space of the root was cut into slices and submitted to push-out test. Failure mode was assessed. Two-way ANOVA, Tukey's, and Dunnett's tests were used for statistical analysis (α = 5%). RESULTS: The type of endodontic sealer (p < 0.001), the time of post cementation (p = 0.038), and the interaction sealer time (p = 0.002) had negative influence on bond strength of fiberglass posts cemented with RelyX™ ARC. AH promoted the highest bond strength mean values (21.20 MPa immediately and 15.54 MPa at 7 days). EN (9.75 MPa immediately and 13.15 MPa at 7 days) and BC (10.43 MPa immediately and 5.73 MPa at 7 days) had lower bond strength than AH, regardless the time of cementation. CONCLUSIONS: AH was the best sealer to obturate the root canal when fiberglass cementation with resin-based cement is planned. CLINICAL RELEVANCE: The correct choice of an endodontic sealer and the adequate time of post cementation may avoid post dislocation caused by low bond strength to dentin.

Effect of rewetting solutions on micropush-out dentin bond strength of new bioceramic endodontic material.

To evaluate the influence of rewetting solutions on bond strength to root dentin of conventional gutta-percha (GP) or niobium phosphate glass-based gutta-percha (GNb) associated with a bioceramic sealer. The root canals of 80 human mandibular premolars were prepared using nickel-titanium instruments and irrigation with sodium hypochlorite and EDTA. The teeth were randomly divided into four groups according to the gutta-percha used: GNb or GP associated with EndoSequence BC Sealer (BC) and the solution for rewetting dentin before filling (distilled water; phosphate buffer saline solution - PBS; simulated body fluid - SBF; or no solution). The root canals were filled with a single cone using warm vertical condensation. Micropush-out bond strengths associated with the filling materials in slices from middle root thirds was determined 30 days after root filling. The failure mode was analyzed with stereoscopic lens. The data were statistically analyzed by two-way ANOVA and Holm-Sidak test (p < 0.05). There was significant difference in the types of gutta-percha (p < 0.001) and in the different rewetting solutions (p = 0.003). The interaction between gutta-percha and rewetting solutions was not significant (p = 0.53). The SBF solution provided an increase in bond strength for both gutta-percha solutions. The GNb+BC (3.42 MPa) association increased bond strength when compared with GP+BC (2.0 MPa). The use of SBF as a dentin rewetting solution increased bond strength in the groups studied. Association of GNb with bioceramic sealer was beneficial, increasing the bond strength to dentin when compared with the association with GP.

Photodynamic therapy with high-power LED mediated by erythrosine eliminates Enterococcus faecalis in planktonic forms.

BACKGROUND: The failure of endodontic treatment is linked to the presence of microorganisms, particularly Enterococcus faecalis, in the root canals. This study evaluated the effectiveness of photodynamic therapy (PDT) using erythrosine irradiated by a high-power curing light on a planktonic suspension culture of E. faecalis. METHODS: Bacterial suspensions of E. faecalis were adjusted and then mixed in a 1:1 proportion, in triplicate, in treatment groups by varying the length of irradiation time (120 and 240s) and the molarity of the erythrosine (5 and 10µM). In order to verify the post-treatment bactericidal effect, a count of the viable bacteria was performed (CFUmL-1) and transformed into Log10 CFU. The one-way ANOVA with Tukey post-hoc test was applied to check for differences between the groups. RESULTS: The bacteria were completely eradicated in the groups that used PDT with 5µM 240s, 10µM 120s and 10µM 240s (p≪0.001). The effect of the PDT 5µM 120s group was significant (p≪0.05) in comparison with the groups using only light or only erythrosine. Positive control (exposure to 2.5% NaClO for 120 and 240s) completely eradicated E. faecalis. The negative control (PBS) did not alter the quantities of E. faecalis CFU with 9.605 Log10 CFU at 120s and 9.621 Log10 CFU at 240s. CONCLUSION: PDT with erythrosine in a concentration of 10µM and high-power LED is capable of totally eliminating E. faecalis in planktonic suspension.

Shear bond strength of different surface treatments in bulk fill, microhybrid, and nanoparticle repair resins.

OBJECTIVES: The purpose of this study was to evaluate the influence of surface treatment and different types of composite resin on the microshear bond strength of repairs. MATERIALS AND METHODS: Seventy-two specimens (n=72) were prepared using a nanoparticle resin and stored in artificial saliva at 37 ± 1°C for 24 h. After this period, the specimens (n=24) were restored with microhybrid resin P60 (3M ESPE), nanoparticle resin Filtek Z350 (3M ESPE), and Bulk Fill Surefil SDR Flow (Dentsply) composite resins. Previously, the surfaces of the samples were treated, forming the following subgroups (n=12): (A) conditioned with 37% phosphoric acid for 30 s, and (B) abrasioned with a diamond tip for 3 s and conditioned with 37% phosphoric acid. In all groups, before insertion of the composite resin, the adhesive system Adper Single Bond 2 was actively applied and photopolymerized for 20 s. RESULTS: The microshear test was executed to assess bond strength. Kruskal-Wallis (p<0.05) and Mann-Whitney statistical tests showed significant statistical difference considering that the bulk-fill resin turned out to have a lower bond strength than the conventional nanoparticle and microhybrid composites. With regard to the technique, the roughening with diamond bur followed by the application of phosphoric acid exhibited values higher than the exclusive use of acid. CONCLUSION: The microshear bond strength of the composite resin repairs varies in accordance with the type of composite resin utilized, and roughening the surface increased the bond strength of these materials.

Laser and photochemotherapy for the treatment of oral mucositis in young patients: Randomized clinical trial.

BACKGROUND: The aim of the present study was to evaluate the effect of low-level laser therapy (LLLT) combined with photochemotherapy (PCT) for the treatment of chemotherapy-induced oral mucositis in young patients. METHODS: A randomized, blind, clinical trial with a split-mouth design was conducted involving a sample of 15 cancer patients aged three to 16 years at the Aldenora Bello Hospital in the city of São Luís, Brazil. The treatments (PCT+LLLT and LLLT alone) were randomly determined for each side of the oral cavity. The patients were blinded to the type of therapy performed on each side. The outcome was the area of the lesion measured in cm2 over an eight-day evaluation period. Treatment and follow up of the lesions under evaluation as well as other lesions occurred until complete remission. Friedman and Wilcoxon tests were employed. Significance was set at a 95% confidence level (α=0.05) and the effect size was calculated. RESULTS: A statistically significant difference was found between therapies for lesion area on Days 6-8 (p=0.020, 0.011 and 0.005, respectively), which was confirmed by the moderate effect size. Lesions submitted to PCT+LLLT had a smaller area at the end of the evaluation period. CONCLUSION: Based on the present findings, PCT+LLLT had a greater therapeutic effect in comparison to LLLT alone regarding the reduction in the degree of severity of chemotherapy-induced oral mucositis.

Effect of rewetting solutions on micropush-out dentin bond strength of new bioceramic endodontic material

Abstract To evaluate the influence of rewetting solutions on bond strength to root dentin of conventional gutta-percha (GP) or niobium phosphate glass-based gutta-percha (GNb) associated with a bioceramic sealer. The root canals of 80 human mandibular premolars were prepared using nickel-titanium instruments and irrigation with sodium hypochlorite and EDTA. The teeth were randomly divided into four groups according to the gutta-percha used: GNb or GP associated with EndoSequence BC Sealer (BC) and the solution for rewetting dentin before filling (distilled water; phosphate buffer saline solution - PBS; simulated body fluid - SBF; or no solution). The root canals were filled with a single cone using warm vertical condensation. Micropush-out bond strengths associated with the filling materials in slices from middle root thirds was determined 30 days after root filling. The failure mode was analyzed with stereoscopic lens. The data were statistically analyzed by two-way ANOVA and Holm-Sidak test (p < 0.05). There was significant difference in the types of gutta-percha (p < 0.001) and in the different rewetting solutions (p = 0.003). The interaction between gutta-percha and rewetting solutions was not significant (p = 0.53). The SBF solution provided an increase in bond strength for both gutta-percha solutions. The GNb+BC (3.42 MPa) association increased bond strength when compared with GP+BC (2.0 MPa). The use of SBF as a dentin rewetting solution increased bond strength in the groups studied. Association of GNb with bioceramic sealer was beneficial, increasing the bond strength to dentin when compared with the association with GP.

Effectiveness of Oral Antiseptics on Tooth Biofilm: A Study in vivo.

AIM: To evaluate the effectiveness of five different mouthwashes through measurement of the plaque index. MATERIALS AND METHODS: Fifty subjects took part in this blind study, randomized into blocks of five groups according to the active ingredient of the mouthwash: CHX group (0.12% chlorhexidine gluconate), essential oils (EO) group, cetylpyridinium chloride (CPC) group, Tri group (triclosan) and Hamamelis virginiana (HV) group. All subjects were evaluated for a reduction in the bacterial plaque index at 7, 14 and 21 days. RESULTS: There was a significant reduction in the mean plaque index during the period of evaluation (p < 0.01), and the reduction during the period of evaluation was different between mouthwashes (p < 0.01). The reduction in the plaque index at the end of 21 days was, in decreasing order, CHX > EO > CPC > Tri > HV. CONCLUSION: The reduction in the plaque index during the period of evaluation was different between the types of mouth-wash. The mouthwash containing the active ingredient chlorhexidine was the most effective, followed by the essential oil, cetylpyridinium chloride, triclosan and H. virginiana.