The Effect of Luting Agents and Ceramic Thickness on the Color Variation of Different Ceramics against a Chromatic Background

Objectives: The aim of this study was to assess the influence of various ceramic thicknesses and luting agents on color variation in five ceramic systems. Methods: Fifteen disc-shaped ceramic specimens (11 mm diameter; shade A3) were fabricated with each of the six veneering ceramics tested, with 1, 1.5, or 2 mm thickness (n=5). Resin composite discs (Z-250, shade C4) were used as bases to simulate a chromatic background. The cementation of the veneers was carried out with an opaque resin-based cement (Enforce, shade C4), a resin-based cement (Enforce, shade A3), or without cement (C4, control group). Color differences (??E*) were determined using a colorimeter. Three-way ANOVA was used to analyze the data, followed by a Tukey post-hoc test (??=.05). Results: The L*a*b* values of the ceramic systems were affected by both the luting agent and the ceramic thickness (P<.05). In general, there was no difference between the control group and the group using the resin-based cement. The use of an opaque luting agent resulted in an increase of the color coordinates a*, b*, L*, producing differences in ??E* values for all ceramics tested, regardless of the thickness (P<.05). For the 2-mm thick veneers, higher values in the color parameters were obtained for all ceramics and were independent of the luting agent used. Conclusions: The association of 2-mm thickness with opaque cement presented the strongest masking ability of a dark colored background when compared to a non- opaque luting agent and the other thicknesses tested. (Eur J Dent 2011;5:245-252

Efeito de substâncias desinfetantes na adesão à dentina de um adesivo de quarta geração

The purpose of the present study was to evaluate the influence of different disinfectant solutions on the tensile bond strength of a fourth generation dentin bonding agent. Forty non carious human molars were selected. Teeth were embedded in acrylic resin and ground until the exposure of a flat superficial dentin surface. Teeth were randomly divided in 4 groups and treated as follows: Group 1 - 2.5% NaOCl for 40 seconds; Group 2 - 2% chlorhexidine for 40 seconds; Group 3 - 1.23% acidulated fluoride for 4 minutes; and Group 4 - control (without disinfectant solution). Following treatments, Scotchbond Multipurpose Plus® (3M) was used according to the manufacturer&#146;s instructions. After that, the test specimens were built with composite resin (Z100®-3M), using a standard Teflon matrix. The specimens were stored in distilled water for 24 hours at a temperature of 37ºC. The tensile strength test was performed using a Mini Instrom testing machine. The mean values obtained for each group, in MPa, were: Group 1 - 7.37 (± 2.51); Group 2 - 11.25 (± 4.65); Group 3 - 9.80 (± 3.11); and Group 4 - 10.96 (± 3.37). The results were submitted to statistical analysis using the ANOVA test, and no statistical significant differences among the groups were found. It can be concluded that the different disinfectant substances used in this research do not adversely affect dentin adhesion.O objetivo do presente trabalho foi avaliar a influência de diferentes substâncias de desinfecção cavitária na resistência à tração de um sistema adesivo de quarta geração. Foram selecionados 40 molares humanos livres de cáries. Os dentes foram incluídos em resina acrílica e desgastados até expor dentina superficial. Os dentes foram divididos aleatoriamente em 4 grupos e assim tratados: Grupo 1 - NaOCl a 2,5% por 40 segundos; Grupo 2 - clorexidina a 2% por 40 segundos; Grupo 3 - flúor-fosfato acidulado a 1,23% por 4 minutos; e Grupo 4 - controle. Após os diferentes tratamentos superficiais o sistema adesivo Scotchbond Multipurpose Plus® (3M) foi aplicado na dentina, de acordo com as instruções do fabricante. Os corpos-de-prova foram confeccionados com resina composta Z100® (3M) utilizando uma matriz padronizada. Após armazenagem em água destilada por 24 horas, os espécimes foram submetidos ao teste de tração em uma máquina universal Mini Instrom. Os resultados em MPa para os diferentes grupos foram: Grupo 1 - 7,37 (± 2,51); Grupo 2 - 11,25 (± 4,65); Grupo 3 - 9,80 (± 3,11); e Grupo 4 - 10,96 (± 3,37). Os dados foram submetido à análise estatística de variância, a qual não permitiu detectar diferenças estatisticamente significantes entre os grupos. Foi possível concluir que as substâncias desinfetantes não ocasionaram alteração na capacidade adesiva do sistema adesivo de quarta geração empregado

Influence of thermal stress on marginal integrity of restorative materials

The aim of this study was to evaluate the influence of thermal stress on the marginal integrity of restorative materials with different adhesive and thermal properties. Three hundred and sixty Class V cavities were prepared in buccal and lingual surfaces of 180 bovine incisors. Cervical and incisal walls were located in dentin and enamel, respectively. Specimens were restored with resin composite (RC); glass ionomer (GI) or amalgam (AM), and randomly assigned to 18 groups (n=20) according to the material, number of cycles (500 or 1,000 cycles) and dwell time (30 s or 60 s). Dry and wet specimens served as controls Specimens were immersed in 1% basic fuchsine solution (24 h), sectioned, and microleakage was evaluated under x40 magnification. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests: Thermal cycling regimens increased leakage in all AM restorations (

Uso de serviços odontológicos em adultos de uma coorte de nascimentos no sul do Brasil

OBJETIVO: Mensurar a prevalência de uso de serviços odontológicos no último ano e os fatores associados em adultos de 31 anos pertencentes à coorte de nascimentos de 1982. MÉTODOS: Estudo transversal, aninhado na coorte de nascimentos de Pelotas de 1982. Em 1997, uma amostra sistemática de 27% dos setores censitários da cidade foi realizada e todos os domicílios desses setores foram visitados, onde 1.076 adolescentes de 15 anos foram entrevistados. Para os estudos de saúde bucal foram sorteados aleatoriamente 900 desses indivíduos, que foram acompanhados também aos 24 e 31 anos. O estudo utilizou dados coletados de 523 indivíduos em 2013 (aos 31 anos). O desfecho foi a ida ao dentista (uso do serviço) no último ano. Fatores demográficos, (sexo), socioeconômicos (renda, escolaridade) e de saúde bucal (motivo e tipo de serviço da consulta, autopercepção de saúde bucal, dor e experiência de cárie - CPOD) foram utilizados como variáveis independentes. As razões de prevalência foram estimadas usando a regressão de Poisson. RESULTADOS: A prevalência de uso de serviços odontológicos no último ano foi de 55,3% (IC95%: 51,0 –59,5%). Na análise ajustada, o motivo e tipo de serviço da consulta, a autopercepção de saúde bucal e o CPOD foram associados ao desfecho. Foi encontrada maior associação com a utilização de serviços odontológicos em indivíduos que visitaram por prevenção e usaram o serviço privado, satisfeitos com a sua saúde bucal e que tinham maior experiência de cárie. CONCLUSÃO: 55,3% da amostra da coorte utilizaram os seviços odontológicos no último ano. Os indivíduos que visitaram o dentista por motivo preventivo, em consulta privada, que estavam muito satisfeitos ou satisfeitos com sua saúde bucal utilizaram em maior proporção esses serviços. Além disso, o maior índice de CPOD também levou ao maior uso.OBJECTIVE: Measure the prevalence of use of dental services in the previous year and associated factors among 31-year-old adults from a birth cohort of 1982. METHODS: This is a cross-sectional study that analyzed a birth cohort of 1982 from the city of Pelotas. In 1997, a systematic sample of 27% of the city’s census sectors was defined and all households in these sectors were visited, where 1,076 15-year-old adolescents were interviewed. For the oral health studies, 900 of these individuals were randomly selected and followed up at 24 and 31 years of age. The study used data collected from 523 individuals in 2013 (at 31 years old). The outcome was visit to the dentist (use of dental services) in the previous year. Demographic factors (sex), socioeconomic factors (income, education), and oral health factors (reason and type of service, self-perception of oral health, dental pain and caries experience - DMFT) were used as independent variables. Prevalence ratios were estimated using Poisson regression. RESULTS: The prevalence of use of dental services in the previous year was 55.3% (95%CI: 51.0–59.5%). In the adjusted analysis, the reason and type of service, self-perception of oral health, and DMFT were associated with the outcome. A stronger association was found with use of dental services in individuals who visited for prevention and used the private service, who were satisfied with their oral health, and who had more caries experiences. CONCLUSION: 55.3% of the cohort sample used dental services in the previous year. Individuals who visited the dentist of private service for preventive reasons, who were very satisfied with their oral health, used these services in a higher proportion. In addition, a higher DMFT index also led to higher use of services

Development of experimental HEMA-free three-step adhesive system.

To evaluate the influence of Bis-EMA 30 on the resin-to-dentin microtensile bond strength (microTBS) and structural reliability of the experimental three-step etch-and-rinse adhesive systems.Five experimental primers containing different dimethacrylate monomer concentrations (0, 10, 20, 40, 60 wt% of the Bis-EMA 30, P0.P60) added to acid monomer and solvents (ethanol/water), and a resin bond (Bis-GMA/TEGDMA, 50/50 wt%) were formulated. The adhesive system Scotchbond MultiPurpose (SBMP, 3M ESPE) was tested as commercial reference. Sixty bovine incisors were randomly separated into six groups, and their superficial coronal dentin was exposed. After acid etching and rinsing, the excess water was removed from the surface with absorbent paper. Each experimental primer was actively applied (30 s), followed by a mild air stream (10 s). The experimental adhesive resin was applied and light activated for 20 s. Resin composite restorations were incrementally built up. The restored teeth were stored in distilled water at 37 degrees C for 24 h, and then sectioned to obtain sticks with a cross-sectional area of approximately 0.5 mm(2), after which 24 specimens per group were subjected to the microTBS test. Data (MPa) were analyzed by One-way ANOVA, Tukey test (alpha=0.05) and Weibull analysis.The P40 group showed microTBS means similar to those of the control (SBMP), whereas both had statistically higher values when compared with the other groups (p0.001). Moreover, P40 showed higher structural reliability, represented by the high Weibull modulus and characteristic strength values. The lowest microTBS was observed in the P0, P10 and P20 groups, which also had low structural reliability.Bis-EMA 30 is a promising monomer to be considered as a substitute for HEMA in adhesive system compositions

Associação entre dor dentária, uso de serviços odontológicos e absenteísmo escolar: Pesquisa Nacional de Saúde do Escolar 2015

Objective: To analyze the association between dental pain, use of dental services and school absenteeism in Brazilian adolescents. Methods: Cross-sectional study with data from the National School Health Survey (PeNSE 2015). The dependent variable of the study was school absenteeism due to health reasons in the last 12 months. Socioeconomic characteristics, dental pain and the use of dental services were the independent variables evaluated. Logistic regression was used to estimate odds ratio (OR) and respective 95% confidence intervals (95%CI). Results: Data of 102,072 schoolchildren were included. The prevalence of absenteeism due to health reasons was 53.7% (95%CI 53.2;54.3). In the adjusted analysis, there was an association between dental pain and school absenteeism (OR=1.35 – 95%CI 1.26;1.45), and an increase in the occurrence of absenteeism according to higher number of dental visits. Conclusion: The results suggest that dental pain and frequency of dental visits may be related to school absenteeism.Objetivo: Analisar a associação entre dor dentária, uso de serviços odontológicos e absenteísmo escolar em adolescentes brasileiros. Métodos: Estudo transversal, sobre dados da Pesquisa Nacional de Saúde do Escolar (PeNSE 2015). A variável dependente do estudo foi o absenteísmo escolar por motivo de saúde nos últimos 12 meses. Características socioeconômicas, dor dentária e utilização de serviços odontológicos foram as variáveis independentes avaliadas. Empregou-se regressão logística, para estimar odds ratio (OR) e respectivos intervalos de confiança de 95% (IC95%). Resultados: Foram incluídos 102.072 escolares. A prevalência de absenteísmo por motivo de saúde foi de 53,7% (IC95% 53,2;54,3). Pela análise ajustada, houve associação entre dor dentária e absenteísmo (OR=1,35 – IC95% 1,26;1,45), e aumento na ocorrência de absenteísmo conforme o maior número de consultas odontológicas. Conclusão: Os resultados sugerem que a dor dentária e a frequência de consultas odontológicas podem estar relacionadas ao absenteísmo escolar

Nano‐/microfiber scaffold for tissue engineering: Physical and biological properties

Alginate hydrogel (AH) has intrinsic physical and biological limitations that hinder its broader application in tissue engineering. We hypothesized that the inclusion of nanofibers in the hydrogel and the use of a biotemplate that mimics nature would enhance the translational potential of alginate hydrogels. In this study, we have shown a method to obtain nano‐/microfibers of titanium (nfTD) and hydroxyapatite (nfHY) using cotton as a biotemplate. These fibers were incorporated in the alginate hydrogel and the mechanical characteristics and biological response to these reinforced materials were evaluated. We observed that these nanofibers resembled the structure of natural collagen and did not mediate cell toxicity. The incorporation of nfTD or nfHY to the AH has not increased the viscosity of the hydrogel. Therefore, this is a feasible method to produce a scaffold with improved physical characteristics, while at the same time generating an enhanced environment for cell adhesion and proliferation. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3051–3058, 2012.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/93772/1/34242_ftp.pd

Triple-blinded randomized clinical trial comparing efficacy and tooth sensitivity of in-office and at-home bleaching techniques

Objective: Our study aims to compare the efficacy and tooth sensitivity following in-office (35% hydrogen peroxide) or at-home (10% carbamide peroxide) bleaching treatments both preceded by 2% potassium nitrate (2%KF) desensitizing gel. Methodology: 130 volunteers were randomly allocated to a) in-office bleaching and a placebo at-home protocol; or b) in-office placebo and at-home bleaching treatment. 2% KF was applied for 10 min before both treatments. Objective: color evaluation was performed (spectrophotometer CIEL*a*b* system and CIEDE2000) to calculate the color change (ΔE00). Subjective evaluation was performed using the VITA classical shade guide followed by shade variation (ΔSGU) at the beginning and end of bleaching treatment and 2 weeks post-bleaching. Tooth sensitivity was daily recorded using a Likert scale varying from 1 (no sensitivity) to 5 (severe sensitivity). Analysis was carried out using non-parametric tests. Results: Regarding the color change, at-home bleaching resulted in significant color improvement compared to in-office treatment for the parameters Δb* (p=0.003) and Δa* (p=0.014). Two weeks post-bleaching, the at-home treatment resulted in significant color improvement compared to in-office treatment for the parameters Δb* (p=0.037) and ΔE00 (p=0.033). No differences were observed in either ΔSGU parameters. Concerning sensitivity, patients treated with in-office bleaching reported more tooth sensitivity than the at-home group only on the first day after bleaching started, without significant differences in the other periods evaluated (p&gt;0.05). Conclusions: At-home and in-office bleaching, preceded by a desensitizing agent, were effective for vital teeth bleaching and 10% carbamide peroxide produced a higher whitening effect than 35% hydrogen peroxide in the short time evaluation. Tooth sensitivity rates were similar for the two techniques tested

Factors associated with prevalence of oral lesions and oral self-examination in young adults from a birth cohort in Southern Brazil

The objective of this study was to assess the prevalence and characteristics of oral lesions and oral self-examination and the association between these variables and life course determinants in a young population. A representative sample (n = 720) of all births occurring in Pelotas, Rio Grande do Sul State, Brazil, in 1982, was investigated and the outcomes were assessed in 2006. Data regarding exploratory variables was collected from other cohort waves. The prevalence of oral lesions was 23.3% (95%CI: 20.3-26.6). A total of 31% of individuals (95%CI: 27.6-34.4) reported never having performed oral self-examination. Multivariable analysis showed that low socio-economic status at birth, lack of oral hygiene instruction from a dentist up to the age of 15 years and smoking habits at the age of 22 year were associated with the presence of oral lesions. Performing oral self-examination was associated with high levels of maternal schooling at birth and having received oral hygiene orientation from a dentist up to the age of 15 years. Socioeconomic and behavioral factors are associated with both presence of oral mucosal lesions and the habit of performing self-examination