Influence of photodynamic therapy, different final irrigants, and ultrasonic activation on the bond strength of glass fiber posts to root dentin.

OBJECTIVE: To evaluate the influence of photodynamic therapy (PDT), different final irrigants, and ultrasonic activation (US) on the bond strength of glass fiber posts (GFP) to root dentin. METHODS: One hundred twenty bovine roots were divided into 12 groups according to PDT application, the type of final endodontic irrigant, and US. The samples were divided into 12 groups (n = 10): G1-DW(distilled water); G2-DW+US; G3-17% EDTA; G4-17% EDTA+US; G5-17% GA (glycolic acid); G6-17% GA+US; G7-PDT+DW; G8-PDT+DW+US; G9-PDT+17% EDTA; G10-PDT+17% EDTA+US; G11-PDT+17% GA; G12-PDT+17% GA+US. After cementing the glass fiber posts with resin cement, roots were sectioned into 2-mm-thick slices. One slice from the cervical third and another from the middle third were used for the push out test (PO), and the other two for the diametral compression test (DC). Thus, 10 samples were obtained per third for each mechanical test (n = 10). Kruskal-Wallis and Student-Newman-Keuls tests were used to analyze PO and DC data, and Pearson's correlation test was used to verify the relationship between the variables. Failure patterns were analyzed with chi-square test. RESULTS: Significant differences were found in the PO test among the experimental groups (p < 0.001; power=1.00). PDT improved bond strength when using EDTA. PDT and US increased bond strength when using GA. Favorable failure patterns occurred more frequently in Group GA+US. There was no correlation between data obtained with PO and DC tests (r = 0.112; p = 0.729). CONCLUSION: PDT provided the highest bond strength values of GFP to root dentin when associated with GA and US or when associated only with EDTA.

Oral leukoplakia-epidemiological survey and histochemical analysis of 107 cases in Brazil.

OBJECTIVE: To perform an epidemiological survey comparing the cell proliferative activity of 107 cases of oral leukoplakia with their clinical and histopathological characteristics. MATERIALS AND METHODS: A cross-sectional, observational, and histological-histochemical study. The cases came from the Histopathological Diagnostic Service of UPF/RS and the School of Dentistry of Araçatuba FOA/UNESP/SP (1986-2016). The histopathological sections were stained using the silver staining (AgNOR) technique and the nuclei of 100 epithelial cells selected randomly were recorded to count the number of nucleolar organizer regions (NORs). The mean NORs per lesion were correlated to clinical and histological characteristics using ANOVA, at 5% significance. RESULTS: Most of the cases included men (62.62%), white (64.49%), and with an average age of 53.94 years. The most probable etiological factors were smoking (44.7%) and alcohol consumption (9.85%). The evolution time of most lesions was fast (33.65%), manifesting mainly in the form of plaques (70.37%) and without symptoms (58.88%). They were located mainly in the cheek mucosa (26.62%) and presented white color (66.35%), well-defined edges (59.81%), firm consistency (47.5%), and keratinized surface (49.53%). Etiological factor (p = 0.003), evolution time (p = 0.006), symptoms (p = 0.029), location (p = 0.020), consistency (p = 0.047), histopathological characteristics (p = 0.004), and superficial keratinization (p = 0.001) were statistically significant regarding the mean NORs of the leukoplakias studied. CLINICAL RELEVANCE: Oral leukoplakias caused by alcohol consumption and/or tobacco use, considering an evolution time of fewer than 12 months, asymptomatic, located in the lower lip or tongue, and with a firm consistency and increased superficial keratinization should be treated more aggressively by the clinician to avoid cancerization.

Ação inibitória de dentifrícios sobre Streptococcus mutans e Candida albicans: estudo in vitro / Inhibitory effect of dentifrices on Streptococcus mutans and Candida albicans: in vitro study

Introdução: este estudo avaliou a ação antimicrobiana de sete dentifrícios nacionais com ação antiplaca ou antimicrobiana, conforme os fabricantes, sobre os patógenos orais Streptococcus mutans e Candida albicans. Métodos: a avaliação dos dentifrícios foi realizada pelo teste de difusão em ágar. Placas de Petri com meios de cultura ágar cérebro coração e ágar Sabourad foram semeadas com suspensão microbiana padronizada de S. mutans e C. albicans. Poços foram confeccionados no ágar semeado e preenchidos com as soluções dos dentifrícios diluídas em 1:1, 1:2, 1:4 e 1:8, além dos controles positivo (solução de clorexidina 2%) e negativo (dentifrício sem princípios ativos). Após incubação por 48h/37°C, os halos de inibição do crescimento microbiano foram medidos com paquímetro e régua milimetrada, e os resultados finais dos halos obtidos em milímetros. Resultados e conclusão: verificou-se que todos os dentifrícios, na diluição de 1:1, foram efetivos sobre C. albicans e S. mutans, exceto o composto de bicarbonato de sódio e extratos vegetais, o qual não inibiu S. mutans. Na diluição de 1:2, somente o dentifrício contendo triclosan inibiu C. albicans, enquanto todos mostraram algum potencial de inibição ao S. mutans. Nas demais diluições, não foram observados halos de inibição de ambos os microrganismos. A C. albicans demonstrou ser mais resistente à ação inibitória dos antimicrobianos dos dentifrícios testados neste estudo. S. mutans demonstrou ser mais sensível à ação dos dentifrícios, no entanto, a diluição durante a escovação dentária reduz a ação inibitória esperada, indicando a importância da remoção mecânica do biofilme.(AU)

Introduction: this study analyzed the antimicrobial activity in seven national dentifrices with antiplaque or antimicrobial substances in their composition, according the manufacturer, on the oral pathogens Streptococcus mutans and Candida albicans. Methods: the dentifrices antimicrobial effect evaluation was carried out by agar diffusion test. S. mutans and C. albicans. Padronized microbial suspension was cultured on Petri dishes containing Brain Hearth Agar and Sabourad Agar, respectively. Wells were prepared in the cultured agar and filled with 1:1, 1:2, 1:4 and 1:8 dilutions of dentifrice solutions, and besides positive (2% chlorhexidine solutions) and negative controls (dentifrices without active ingredients). After 48h/37°C incubation, the microbial growing inhibition zones were measured with a paquimeter and a millimeter rule, being the final zone results obtained in millimeters. Results and conclusion: on 1:1 dilution, all dentifrices were effective on C. albicans and S. mutans, except one with vegetal extract and sodium bicarbonate composition, which did not inhibit S. mutans. In 1:2 dilution, only tricolsan-containing dentifrice inhibited C. albicans, while all dentifrices presented some inhibition potential on S. mutans. There were no inhibition zones for both microorganims in other dilutions. We concluded that C. albicans showed to be more resistant to antimicrobial agents tested in the dentifrices, in this study. S. mutans showed to be more sensitive to tested dentifrices, however, the product dilution during toothbrushing reduces the expected inhibitory action, strengthening the importance of the mechanical removal of dental biofilm.(AU)