Abstract The purpose of this population-based, observational, and cross-sectional study was to evaluate alterations in the oral cells of a population of older people from a Brazilian rural area, using the micronucleus technique to investigate possible associated genotoxic factors. A questionnaire was applied and clinical examination and collection of oral mucosal cells were performed for all older people (≥ 60 years) from a town in southern Brazil. Demographic and socioeconomic variables, deleterious habits (drinking and tobacco use), presence of gastro-oesophageal reflux disease (GERD), and the use of proton pump inhibitors (PPIs) were considered the exposure variables, whereas metanuclear changes (MCs) and the prevalence of cell micronuclei (MN) were considered outcomes. Out of 489 older people, 447 were included in the study, among whom 50.8% were men with a mean age of 70.9 years and 83.9% had a monthly family income greater than US$ 500.00. GERD symptoms were present in 36.2% of the individuals, and 29.1% used PPIs daily, 53.3% consumed alcoholic beverages, and 46.7% used tobacco. The analysis of 1,000 oral mucosal cells per subject showed a MN frequency of 0–2 per individual, and MCs were detected with an average of 15 units per individual (median = 11 per individual). Poisson regression did not show statistical association between the exposure variables and the outcomes (presence of MN and MCs), except for the use of PPIs, which was a protective factor for the prevalence of MN [PR 0.6 (CI 0.3–0,9)]. Age, sex, family income, tobacco use and drinking, and GERD were not associated with the number of MN and MCs in oral mucosal cells of the investigated older people.

Coronal leakage is an important factor affecting the outcome of endodontic therapy. This study evaluated the microbial leakage (ML) and the apical inflammatory response (AIR) in dog's teeth after root canal filling with three endodontic sealers, post preparation and exposure to the oral environment, testing the hypothesis that there is a positive correlation between these two histological parameters (ML and AIR). Sixty-four root canals of 8 mongrel dogs were cleaned, shaped and randomly distributed into groups according to the sealer to be used: Sealer 26 (n=18); AH Plus (n=18); RoekoSeal (n=19); no sealer - control group (n=9). Root canals were filled by the lateral condensation technique. Post space preparation left 4 mm of filling material in the apical root third, and specimens were exposed to the oral environment for 90 days. The dogs were killed and jaw blocks were histologically processed using Brown & Brenn and HE staining techniques. ML and AIR were scored from 1 to 4. Results were analyzed statistically using ANOVA, Duncan's post-hoc test and Spearman's correlation. ML and AIR score means were: Sealer 26 - 2.44±0.98 and 2.50±0.70; AH Plus - 2.50±0.78 and 2.22±0.54; RoekoSeal - 1.84±0.95 and 2.63±0.83; Control - 2.56±1.23 and 3.11±0.60. Statistically significant differences in AIR scores were found between the AH Plus and control groups (p<0.05). Although RoekoSeal had the lowest ML means, and AH Plus, the lowest AIR means after 90-day exposure to the oral environment, no statistically significant differences were found between the three sealers under study, and no correlation was found between ML and AIR.

OBJETIVO: determinar a influência de três sistemas distintos de instrumentos rotatórios para alargamento cervical na determinação do comprimento real de trabalho. MATERIAL E MÉTODOS: Trinta primeiros molares inferiores foram submetidos ao acesso endodôntico convencional e odontometria inicial pelo método visual, utilizando-se para irrigação/aspiração da câmara pulpar o hipoclorito de sódio a 5%. Procedeu-se a ampliação cervical dos canais mésio-vestibulares empregando-se diferentes alargadores cervicais. De acordo com o sistema de ampliação cervical empregado, as 30 amostras foram divididas aleatoriamente em 3 grupos de 10 dentes cada. No Grupo 1 as brocas de Gates-Glidden foram utilizadas para a ampliação cervical; no Grupo 2, Orifice Openers foram empregados; e, no Grupo 3, foi usado o sistema La Axxess. Foram utilizadas em ordem crescente, duas numerações do sistema rotatório correspondente a cada grupo e, após, realizou-se a odontometria final. A leitura das duas tomadas odontométricas foi realizada com paquímetro digital, em milímetros, considerando-se duas casas decimais para averiguar a provável discrepância entre ambas as tomadas. RESULTADOS: a análise de variância (ANOVA) e o teste de Tukey (p£ 0,05) demonstraram diferença estatística entre o Grupo 1 e os Grupos 2 e 3. CONCLUSÕES: todos os grupos apresentaram encurtamento do comprimento de trabalho após alargamento cervical; os grupos preparados com instrumentos La Axxes e Orifice Opener apresentaram os melhores resultados.

OBJECTIVE: to investigate the influence of three different rotary systems for cervical flaring on establishment of the real working length. MATERIAL AND METHODS: Thirty mandibular first molars were submitted to conventional endodontic access and initial working length measurement, followed by irrigation/suction of the pulp chamber with 5% sodium hypochlorite. Teeth were randomly divided into 3 groups (n=10) and cervical flaring of the mesiobuccal canals were performed using one of the following instrument systems: Group 1 - Gates-Glidden burs; Group 2 - Orifice Openers; Group 3 - La Axxess system. Two subsequent numbers of instruments of each rotary system were used and the final working length was recorded. A digital calyper was used to record the working length, in millimeters, to investigate a possible discrepancy between initial and final measurements. RESULTS: Analysis of variance (Anova) na Tukey test revealed statistical difference between Group 1 and Groups 2 and 3 (p£ 0.05). CONCLUSIONS: all groups presented shorter working length after cervical flaring; groups prepared with instruments La Axxes and Orifice Opener presented the best results among the systems studied.

O sucesso clínico de procedimentos adesivos para restaurações cerâmicas e reparo destas restaurações depende da qualidade e durabilidade da adesão entre a cerâmica e a resina. A qualidade desta adesão dependerá dos mecanismos adesivos que são controlados em parte pelo tratamento de superfície que promove uma união micro-mecânica e/ou química com o substrato. O objetivo desta revisão é correlacionar a tenacidade de fratura aparente da interface adesiva (K A) com os parâmetros morfológicos da superfície de fratura de sistemas cerâmica-resina em função do tratamento da superfície cerâmica. Esta análise é desenvolvida para identificar os mecanismos que promovem a adesão nestes sistemas cerâmica-resina e uma metodologia apropriada para testar a resistência adesiva produzindo resultados relevantes da performa adesiva.

The clinical success of resin bonding procedures for indirect ceramic restorations and ceramic repairs depends on the quality and durability of the bond between the ceramic and the resin. The quality of this bond will depend upon the bonding mechanisms that are controlled in part by the surface treatment that promote micromechanical and/or chemical bonding to the substrate. The objective of this review is to correlate interfacial toughness (K A) with fracture surface morphological parameters of the dental ceramic-resin systems as a function of ceramic surface treatment. This analysis is designed to identify mechanisms that promote adhesion of these ceramic-resin systems and an appropriate bond test method to yield relevant adhesion performance data.

O objetivo deste estudo foi testar duas hipóteses: (1) a deposição de sílica afeta a resistência adesiva entre cerâmicas e cimento resinoso; (2) a resistência adesiva é afetada pelo tipo de cerâmica. Dez blocos (5 x 6 x 8 mm³) das cerâmicas In-Ceram Zircônia (ZR) e Procera AllCeram (PR) foram confeccionados e duplicados em resina composta. Cinco blocos de cada cerâmica foram assim tratados: (1) ZR + GB (jateamento com partículas de Al2O3) + silano; (2) ZR + SC (deposição de sílica/silanização - Sistema CoJet); (3) PR + GB; (4) PR + SC. Os blocos de cerâmica-compósito foram cimentados com Panavia F e armazenados em água destilada (37ºC / 7 dias). Eles foram então cortados para obter corpos-de-prova em forma de barras (n=30) com uma área adesiva de 0,6 ± 0,1mm². Os cp foram submetidos ao teste de microtração em uma máquina de ensaio universal (1mm.min-1). Os valores de resistência adesiva (sigma) foram submetidos à análise de variância (2 fatores) e ao teste de Tukey (alfa = 0,05). As médias de sigma (MPa) e os desvios padrão foram: 1) 15,1 (5,3); 2) 26,8 (7,4); 3) 12,7 (2,6); 4) 18,5 (4,7). A deposição de sílica na superfície cerâmica apresentou maior que o mesmo substrato tratado com GB. Além disso, ZR (com fase vítrea) apresentou maior sigma que PR (sem fase vítrea).

The objective of this study was to test two hypotheses: (1) silica coating affects the bond strength between ceramics and a resin cement; (2) bond strength is affected by the type of ceramic. Twelve blocks 5 x 6 x 8 mm of In-Ceram Zirconia (ZR) and twelve Procera AllCeram (PR) ceramics were made and duplicated in composite. Five blocks of each ceramic were treated as follows: (1) ZR + GB (laboratorial airborne particles abrasion with Al2O3 particles) + silane; (2) ZR + SC (chairside tribochemical silica coating system, Cojet); (3) PR + GB; (4) PR + SC. Two treated samples of ceramic were analyzed under SEM. The ceramic-composite blocks were cemented with Panavia F and stored in 37ºC distilled water for 7 days. They were then cut to produce bar specimens (n=30) with a bonding area of 0.6±0.1mm². Specimens were loaded to failure under tension in a universal testing machine (1 mm/min). Bond strength (sigma) values were statistically analyzed using ANOVA (Two-way) and Tukey (alpha = 0.05). Mean sigma (MPa) and standard deviation were as follows: 1) 15.1 ± 5.3; 2) 26.8 ± 7.4; 3) 12.7 ± 2.6; 4) 18.5 ± 4.7. Silica coated surfaces showed statistically higher sigma than the same substrate treated with GB only. In addition, ZR (with vitreous phase) showed higher ó than PR (without vitreous phase).

O apelo das cerâmicas como materiais odontológicos é baseado no seu peso leve, dureza alta, inércia química e características tribológicas únicas. Um dos maiores objetivos atuais das pesquisas com cerâmicas é a produção de materiais resistentes que possam oferecer uma utilização confiável para o uso odontológico. A quantificação dos parâmetros microestruturais é importante para o desenvolvimento da relação entre estrutura e propriedades. A análise quantitative da microestrutura fornece uma associação entre a composição, as propriedades físicas, e as características estruturais dos materiais. A confiabilidade estrutural das cerâmicas odontológicas é um fator importante para o sucesso clínico das restaurações cerâmicas. Distribuições complexas de estresse estão presentes na maioria das situações clínicas e, por isso, os valores isolados de resistência não podem ser diretamente extrapolados para prever a durabilidade estrutural dos materiais.

The appeal of ceramics as structural dental materials is based on their light weight, high hardness values, chemical inertness, and anticipated unique tribological characteristics. A major goal of current ceramic research and development is to produce tough, strong ceramics that can provide reliable performance in dental applications. Quantifying microstructural parameters is important to develop structure/property relationships. Quantitative microstructural analysis provides an association among the constitution, physical properties, and structural characteristics of materials. Structural reliability of dental ceramics is a major factor in the clinical success of ceramic restorations. Complex stress distributions are present in most practical conditions and strength data alone cannot be directly extrapolated to predict structural performance.