COVID-19 incidence, severity, medication use, and vaccination among dentists: survey during the second wave in Brazil.

OBJECTIVE: This cross-sectional study with dentists in Brazil assessed the COVID-19 incidence and severity, its vaccination status, and the level of confidence in vaccines in May 2021 (COVID-19 second wave). The medications used to prevent or treat COVID-19, including controversial substances (vitamin D, ivermectin, zinc, and chloroquine), were analyzed. METHODOLOGY: Dentists were recruited by email and responded to a pretested questionnaire until May 31, 2021. Bivariate and multivariate regression analyses were performed (α=0.05). Prevalence ratios were calculated for the association between professional characteristics and two outcomes: SARS-CoV-2 infection and use of controversial substances. RESULTS: In total, 1,907 responses were received (return rate of 21.2%). One third of dentists reported intermediate levels of confidence in the safety and efficacy of COVID-19 vaccines, but 96% had received at least one vaccine dose, mainly CoronaVac. The effect of the pandemic on dental practice was classified as lower/much lower, in comparison with the first wave, by 46% of participants. Moreover, 27% of dentists had already tested positive for SARS-CoV-2 and about 50% had relatives or friends who had been hospitalized or died from COVID-19. At least one medication was used by 59% of participants and 43% used two or more substances. Vitamin D (41%), ivermectin (35%), and zinc (29%) were the most frequent substances. More experienced dentists (≥21 years of professional experience) were 42% more likely to use controversial substances than less experienced dentists. The prevalence of use of controversial substances was 30% higher among dentists with residency or advanced training, such as postgraduate degrees, in comparison with participants holding MSc or PhD degrees. Participants with low confidence in vaccines were 2.1 times more likely to use controversial substances than participants with a very high confidence. CONCLUSION: The results of this study show the high severity of the COVID-19 pandemic in Brazil and raised questions about the use of scientific evidence by dentists in their decision to use controversial substances.

A multi-country survey on the impact of COVID-19 on dental practice and dentists' feelings in Latin America.

BACKGROUND: The COVID-19 pandemic has significantly influenced the routine of healthcare workers. This study investigated the impact of the pandemic on dental practice and dentists' feelings in Latin America. METHODS: A survey was conducted with dentists from 11 Spanish-speaking Latin American countries in September-December 2020. Professionals were invited by email and via an open campaign promoted on social media. The questions investigated dental care routines, practice changes, and feelings about the pandemic. Descriptive statistics were used to identify frequencies and distributions of variables. Proportions were compared using chi-square tests. RESULTS: A total of 2127 responses were collected from a sample with diverse demographic, sex, work, and education characteristics. The impact of COVID-19 was considered high/very high by 60% of respondents. The volume of patients assisted weekly was lower compared with the pre-pandemic period (mean reduction = 14 ± 15 patients). A high rate of fear to contracting the COVID-19 at work was observed (85%); 4.9% of participants had a positive COVID-19 test. The main professional challenges faced by respondents were reduction in the number of patients or financial gain (35%), fear of contracting COVID-19 (34%), and burden with or difficulty in purchasing new personal protective equipment (22%). The fear to contracting COVID-19 was influenced by the number of weekly appointments. A positive test by the dentists was associated with their reports of having assisted COVID-19 patients. The most cited feelings about the pandemic were uncertainty, fear, worry, anxiety, and stress. Negative feelings were more prevalent for professionals who did not receive training for COVID-19 preventive measures and those reporting higher levels of fear to contract the disease. CONCLUSION: This multi-country survey indicated a high impact of the pandemic on dental care routines in Latin America. A massive prevalence of bad feelings was associated with the pandemic.

COVID-19 incidence, severity, medication use, and vaccination among dentists: survey during the second wave in Brazil

Abstract Objective This cross-sectional study with dentists in Brazil assessed the COVID-19 incidence and severity, its vaccination status, and the level of confidence in vaccines in May 2021 (COVID-19 second wave). The medications used to prevent or treat COVID-19, including controversial substances (vitamin D, ivermectin, zinc, and chloroquine), were analyzed. Methodology Dentists were recruited by email and responded to a pretested questionnaire until May 31, 2021. Bivariate and multivariate regression analyses were performed (α=0.05). Prevalence ratios were calculated for the association between professional characteristics and two outcomes: SARS-CoV-2 infection and use of controversial substances. Results In total, 1,907 responses were received (return rate of 21.2%). One third of dentists reported intermediate levels of confidence in the safety and efficacy of COVID-19 vaccines, but 96% had received at least one vaccine dose, mainly CoronaVac. The effect of the pandemic on dental practice was classified as lower/much lower, in comparison with the first wave, by 46% of participants. Moreover, 27% of dentists had already tested positive for SARS-CoV-2 and about 50% had relatives or friends who had been hospitalized or died from COVID-19. At least one medication was used by 59% of participants and 43% used two or more substances. Vitamin D (41%), ivermectin (35%), and zinc (29%) were the most frequent substances. More experienced dentists (≥21 years of professional experience) were 42% more likely to use controversial substances than less experienced dentists. The prevalence of use of controversial substances was 30% higher among dentists with residency or advanced training, such as postgraduate degrees, in comparison with participants holding MSc or PhD degrees. Participants with low confidence in vaccines were 2.1 times more likely to use controversial substances than participants with a very high confidence. Conclusion The results of this study show the high severity of the COVID-19 pandemic in Brazil and raised questions about the use of scientific evidence by dentists in their decision to use controversial substances.

Ceramic Laminate Veneers Luted with Preheated Resin Composite: A 10-Year Clinical Report.

Resin cement and preheated restorative resin composite may be used for luting laminate veneers. The main advantage of resin composite is increased wear resistance, which could lead to better marginal performance in long term. This article reports a clinical treatment with feldspar laminate veneers luted to the maxillary teeth with preheated resin composite in a private practice. Case was finalized in May 2009 and followed by 10 years. Excellent clinical service and remarkable long-lasting marginal integrity were observed after 123 months. Scanning electron microscopy analysis showed no wear, gaps, or ditching at the margins. Restorative margins showed a smooth transition between ceramic and tooth with no signs of degradation. Preheated resin composite for luting ceramic laminate veneers may be considered an excellent clinical option.

Charcoal-based dentifrices and powders: analyses of product labels, Instagram engagement, and altmetrics.

This study identified charcoal-based dentifrices and abrasive powders sold in Brazil and analyzed their label information. The products were searched in four online shopping platforms. The same products were searched on Instagram and their engagement metrics were investigated. Furthermore, a literature review of international publications assessing charcoal dentifrices and powders was conducted, and altmetrics were collected (Altmetric and PlumX). Thirty-six products were found with prices between $0.4-22 USD. Most frequent words in product description were sodium, stain, whitening, oil, xylitol, and coconut. Only 3 products contained fluoride. Bactericidal, antiviral, antifungal, and anti-inflammatory activities were indicated, in addition to non-scientific claims such as calming teeth or increasing oral immunity. In total, 72% of products had Instagram profiles, which generally showed low engagement rates (81%) and medium audience quality scores (65%). Twenty-two articles were found in the literature, from which 21 were in vitro studies. The single clinical study was sponsored by a charcoal product and had no control group. In total, 23% of studies showed positive results and 55% reported negative results for the charcoal products, which included no whitening ability, increased roughness, surface alterations, and lower demineralization prevention ability. Altmetric scores for the included articles varied from 0 to 55, with 40.9% of studies mentioned online. In conclusion, charcoal-based products are using marketing strategies on Instagram but their current engagement with the public is not high. Consumers are being exposed to charcoal products whose potential risks to health are still unknown.

Email Vs. Instagram Recruitment Strategies For Online Survey Research.

In this study, we describe a method for reaching a target population (i.e., dentists practicing in Brazil) to engage in survey research using traditional e-mail invites and recruitment campaigns created on Instagram. This study addresses methodological aspects and compares respondents reached by different methods. A pre-tested questionnaire was used and participants were recruited for 10 days via a source list of email addresses and two discrete Instagram organic open campaigns. A total of 3,122 responses were collected: 509 participants were recruited by email (2.1% response rate) and 2,613 by the two Instagram campaigns (20.7% and 11.7% conversion rates), respectively. Response/min collection rates in the first 24 h ranged between 0.23 (email) and 1.09 (first campaign). In total, 98.8% of all responses were received in the first 48 h for the different recruitment strategies. There were significant differences for all demographic variables (p< 0.001) between email and Instagram respondents, except for sex (p=0.37). Instagram respondents were slightly older, had more professional experience (years in practice), and a higher graduate education level than email respondents. Moreover, most email and Instagram respondents worked in the public sector and private practice, respectively. Although both strategies could collect responses from all Brazilian regions, email responses were slightly better distributed across the five territorial areas compared to Instagram. This study provides evidence that survey recruitment of a diverse, large population sample using Instagram is feasible. However, combination of email and Instagram recruitment led to a more diverse population and improved response rates.

Charcoal-based dentifrices and powders: analyses of product labels, Instagram engagement, and altmetrics

Abstract This study identified charcoal-based dentifrices and abrasive powders sold in Brazil and analyzed their label information. The products were searched in four online shopping platforms. The same products were searched on Instagram and their engagement metrics were investigated. Furthermore, a literature review of international publications assessing charcoal dentifrices and powders was conducted, and altmetrics were collected (Altmetric and PlumX). Thirty-six products were found with prices between $0.4-22 USD. Most frequent words in product description were sodium, stain, whitening, oil, xylitol, and coconut. Only 3 products contained fluoride. Bactericidal, antiviral, antifungal, and anti-inflammatory activities were indicated, in addition to non-scientific claims such as calming teeth or increasing oral immunity. In total, 72% of products had Instagram profiles, which generally showed low engagement rates (81%) and medium audience quality scores (65%). Twenty-two articles were found in the literature, from which 21 were in vitro studies. The single clinical study was sponsored by a charcoal product and had no control group. In total, 23% of studies showed positive results and 55% reported negative results for the charcoal products, which included no whitening ability, increased roughness, surface alterations, and lower demineralization prevention ability. Altmetric scores for the included articles varied from 0 to 55, with 40.9% of studies mentioned online. In conclusion, charcoal-based products are using marketing strategies on Instagram but their current engagement with the public is not high. Consumers are being exposed to charcoal products whose potential risks to health are still unknown.

Resumo Este estudo identificou dentifrícios e pós abrasivos de carvão vendidos no Brasil e analisou suas informações de rótulo. Os produtos foram pesquisados em quatro plataformas de compras online. Os mesmos produtos foram pesquisados no Instagram e métricas de engajamento dos perfis foram investigadas. Além disso, foi realizada uma revisão da literatura buscando publicações internacionais que avaliaram dentifrícios e pós de carvão; dados de altmetria foram coletados (Altmetric e PlumX). Foram encontrados 36 produtos com preços entre US$ 0,4-22. As palavras mais frequentes na descrição dos produtos foram sódio, mancha, clareamento, óleo, xilitol e coco. Apenas 3 produtos continham flúor. Foram indicadas atividades bactericidas, antivirais, antifúngicas e anti-inflamatórias, além de alegações não-científicas como acalmar dentes ou aumentar a imunidade oral. No total, 72% dos produtos tinham perfis no Instagram, que geralmente apresentavam baixas taxas de engajamento (81%) e média qualidade de audiência (65%). Vinte e dois artigos foram encontrados na literatura, dos quais 21 foram estudos in vitro. O único estudo clínico foi patrocinado por um produto de carvão e não tinha grupo controle. No total, 23% dos estudos apresentaram resultados positivos e 55% relataram resultados negativos para os produtos de carvão, que incluíram incapacidade de clareamento, aumento da rugosidade, alterações superficiais e menor capacidade de prevenção da desmineralização do esmalte. A altmetria dos artigos incluídos variou de 0 a 55, com 40,9% dos estudos sendo mencionados online. Em conclusão, os produtos à base de carvão estão usando estratégias de marketing no Instagram, mas seu engajamento atual com o público não é alto. Consumidores estão sendo expostos a produtos de carvão cujos potenciais riscos à saúde ainda são desconhecidos

Email vs. instagram recruitment strategies for online survey research

Abstract In this study, we describe a method for reaching a target population (i.e., dentists practicing in Brazil) to engage in survey research using traditional e-mail invites and recruitment campaigns created on Instagram. This study addresses methodological aspects and compares respondents reached by different methods. A pre-tested questionnaire was used and participants were recruited for 10 days via a source list of email addresses and two discrete Instagram organic open campaigns. A total of 3,122 responses were collected: 509 participants were recruited by email (2.1% response rate) and 2,613 by the two Instagram campaigns (20.7% and 11.7% conversion rates), respectively. Response/min collection rates in the first 24 h ranged between 0.23 (email) and 1.09 (first campaign). In total, 98.8% of all responses were received in the first 48 h for the different recruitment strategies. There were significant differences for all demographic variables (p< 0.001) between email and Instagram respondents, except for sex (p=0.37). Instagram respondents were slightly older, had more professional experience (years in practice), and a higher graduate education level than email respondents. Moreover, most email and Instagram respondents worked in the public sector and private practice, respectively. Although both strategies could collect responses from all Brazilian regions, email responses were slightly better distributed across the five territorial areas compared to Instagram. This study provides evidence that survey recruitment of a diverse, large population sample using Instagram is feasible. However, combination of email and Instagram recruitment led to a more diverse population and improved response rates.

Resumo Neste estudo, descrevemos um método para atingir uma população-alvo (dentistas atuando no Brasil) para se engajar em pesquisa do tipo enquete (survey) utilizando convites tradicionais por e-mail e campanhas de recrutamento criadas no Instagram. Este estudo aborda aspectos metodológicos e compara as pessoas entrevistadas alcançadas por diferentes métodos. Foi utilizado um questionário pré-testado e os(as) participantes foram recrutados(as) por 10 dias por meio de uma lista de endereços de e-mail e duas campanhas abertas orgânicas independentes no Instagram. Foram coletadas 3122 respostas: 509 participantes foram recrutados(as) por e-mail (taxa de resposta 2,1%) e 2613 pelas duas campanhas do Instagram (taxas de conversão 20,7% e 11,7%), respectivamente. As taxas de coleta de resposta/min nas primeiras 24h variaram entre 0,23 (e-mail) e 1,09 (primeira campanha). No total, 98,8% das respostas foram recebidas nas primeiras 48h para as diferentes estratégias de recrutamento. Houve diferenças significativas para todas as variáveis demográficas (p<0,001) entre recrutados(as) por e-mail e Instagram, com exceção de sexo (p=0,37). As pessoas recrutadas via Instagram eram um pouco mais velhas, tinham mais experiência profissional (anos na prática) e nível de pós-graduação superior às entrevistadas por e-mail. Além disso, a maioria dos entrevistados por e-mail e Instagram trabalhava no setor público e na prática privada, respectivamente. Embora ambas estratégias tenham sido capazes de coletar respostas de todas as regiões brasileiras, as respostas por e-mail foram ligeiramente melhor distribuídas nas cinco áreas territoriais em comparação ao Instagram. Este estudo fornece evidências de que o recrutamento de uma amostra de população diversificada e grande usando o Instagram é viável. No entanto, a combinação de e-mail e Instagram no recrutamento levou a uma população mais diversificada e melhores taxas de resposta.

COVID-19 challenges to dentistry in the new pandemic epicenter: Brazil.

A nationwide survey of dentists was carried out in Brazil, a new pandemic epicenter, to analyze how dental care coverage has been affected in public versus private networks, changes in routine and burdens, and how local prevalence of COVID-19 affects dental professionals. Dentists were recruited via email and Instagram®. Responses to a pre-tested questionnaire were collected May 15-24, 2020. COVID-19 case/death counts in the state where respondents work was used to test associations between contextual status and decreases in weekly appointments, fear of contracting COVID-19 at work, and current work status (α = 0.05). Over 10 days, 3,122 responses were received (response rate ~2.1%) from all Brazilian states. Work status was affected for 94%, with less developed regions being more impacted. The pandemic impact on clinical routine was high/very high for 84%, leading to varied changes to clinic infrastructure, personal protective equipment use, and patient screening, as well as increased costs. COVID-19 patients had been seen by 5.3% of respondents; 90% reported fearing contracting COVID-19 at work. Multilevel models showed that greater case and death rates (counted as 1000 cases and 100 deaths per million inhabitants) in one's state increased the odds of being fearful of contracting the disease (18% and 25%). For each additional 1000 cases/100 deaths, the odds of currently not working or treating only emergencies increased by 36% and 58%. The reduction in patients seen weekly was significantly greater in public (38.7±18.6) than in private clinics (22.5±17.8). This study provides early evidence of three major impacts of the pandemic on dentistry: increasing inequalities due to coverage differences between public and private networks; the adoption of new clinical routines, which are associated with an economic burden for dentists; and associations of regional COVID-19 incidence/mortality with fear of contracting the disease at work.

Evaluation of alternative photoinitiator systems in two-step self-etch adhesive systems.

OBJECTIVE: The aim of this study was to evaluate the effect of different photoinitiator systems on the cell viability and physico-chemical properties of an experimental adhesive resin of a two-step self-etch adhesive system. METHODS: Eight photoinitiators and coinitiators were evaluated, camphorquinone (CQ); ethyl-dimethylamino benzoate (EDAB); diphenyliodonium hexafluorophosphate (DPIHFP); 1,3-benzodioxole (BDO); piperonyl alcohol (AP); 1,3-diethyl-2-thiobarbituric acid (TBA); bisphenyl phosphinic oxide (BAPO); and diphenyl phosphinic oxide (TPO). Seven experimental adhesive resins (Bis-GMA:TEGDMA - 1:1 by wt%) were formulated by varying the initiation systems: RCQ+EDAB (control), RCQ+EDAB+DPHFP, RCQ+BDO, RCQ+AP, RCQ+TBA, RBAPO and RTPO. The cell viability of the different photoinitiators in their isolated form and after being incorporated into the adhesive resins was evaluated using the MTT assay. The degree of conversion within the hybrid layer (DC in situ) was evaluated by micro-Raman spectroscopy; the polymerization kinetics, by FTIR spectroscopy. The water sorption (Wsp) and solubility (Wsl) were calculated by using percentage of gain and loss of mass. Data were analyzed using One-way ANOVA and Kruskal-Wallis tests (α=0.05). RESULTS: When evaluated in their isolated form, the DPIHFP was considered cytotoxic in all concentrations evaluated. When incorporated into and adhesive resin, RCQ+TBA presented higher cell viability values than control and the highest values of DC in situ (p<0.05). Additionally, the use of CQ+TBA showed a higher cell viability when compared with the conventional CQ+EDAB system. SIGNIFICANCE: The pair CQ+TBA could be potentially useful in the development of materials with improved biocompatibility.

Restoration of a single darkened central incisor with a modified ceramic veneer.

Restoring a single darkened central incisor can be challenging. Both direct and indirect options may be acceptable to mask discoloration and achieve functional requirements. This report describes placement of a modified feldspathic porcelain veneer to reproduce the appearance of a maxillary central incisor discolored after trauma.

Bonding to Sound and Caries-Affected Dentin: A Systematic Review and Meta-Analysis.

PURPOSE: This study systematically reviewed the literature to compare the bonding ability of dental adhesives applied to sound dentin (SoD) vs caries-affected dentin (CAD). MATERIALS AND METHODS: Three international databases (Medline/PubMed, Scopus, and Web of Science) were searched. Eligible studies which evaluated the bond strength to both SoD and CAD were included. Random effects meta-analyses were conducted to calculate pooled mean difference between substrates, separately for etch-and-rinse and self-etch adhesives. Subgroup analyses were carried out to explore heterogeneity considering the methods used for removal of infected carious dentin. A comparison between etch-and-rinse and self-etch adhesives restricted to CAD was also performed. Statistical heterogeneity was considered using the I2 test. The risk of bias of all included studies was assessed. RESULTS: In total, 2260 articles were found, 65 were selected for full-text reading, and 40 studies were included. The meta-analyses favored SoD over CAD for both etch-and-rinse (effect size: -10.04; 95% confidence interval [CI]: -11.94, -8.14; I2 = 95%) and self-etch adhesives (effect size: -6.76; 95% CI: -8.23, -5.30; I2 = 89%). In the subgroup analyses, SoD was favored irrespective of the method used for caries removal (effect size ≤ -4.86; I2 ≥ 28%): excavation (manual or with burs), grinding with abrasive papers, combination of more than one method, and when the method was not mentioned. The meta-analysis restricted to CAD favored etch-and-rinse over self-etch adhesives (effect size: 3.13; 95% CI: 1.82, 4.44; I2 = 72%). Most included studies were judged as having an unclear risk of bias. CONCLUSION: Bonding to SoD yields better results compared to CAD. Etch-and-rinse adhesives performed better than self-etch adhesives when applied to CAD.

BAPO as an alternative photoinitiator for the radical polymerization of dental resins.

OBJECTIVES: This study evaluated the performance of phenylbis (2,4,6-trimethylbenzoyl)-phosphine oxide (BAPO) as an alternative photoinitiator in the polymerization kinetics (PK), flexural strength (σ) and elastic modulus (E) of a model dental resin. METHODS: A monomer mixture based on Bis-GMA and TEGDMA was used as model dental resin. Initially a screening was performed to evaluate BAPO concentrations (0.125, 0.25, 0.50, 1, 2, and 4 mol%). Photoinitiator systems were formed with the combination of camphorquinone (CQ), ethyl-dimethylamino benzoate (EDAB), diphenyliodonium hexafluorophosphate (DPIHFP), and BAPO. Groups with unitary photoinitiator systems (BAPO and CQ), binary (BAPO+EDAB, BAPO+DPIHFP and CQ+EDAB), ternary (BAPO+CQ+EDAB, BAPO+CQ+DPIHFP, BAPO+EDAB+DPIHFP and CQ+EDAB+DPIHFP) and quaternary (BAPO+CQ+EDAB+DPIHFP) were formulated for evaluation. Real-time Fourier transform infrared spectroscopy was used to investigate the PK and test mini-bending to evaluate σ and E. RESULTS: When only CQ was used, a slow polymerization reaction was observed and a lower monomer conversion. When only BAPO was used as photoinitiator an increase in the polymerization rate was observed and conversion was higher than CQ+EDAB. The ternary system (BAPO+EDAB+DPIHFP) showed the highest polymerization and conversion rate, in short photo-activation time. SIGNIFICANCE: BAPO it is a potential photoinitiator for the photopolymerization of dental materials.

Effect of immediate and delayed light activation on the mechanical properties and degree of conversion in dual-cured resin cements.

We evaluated the effect of activation mode (immediate or delayed light activation vs. no light activation) on diametral tensile strength (DTS), elastic modulus, ultimate tensile strength (UTS), and degree of conversion (DC) in dual-cured resin cements. Three resin cements were evaluated: Enforce, RelyX ARC, and Panavia F. The mixed cements were inserted into circular molds for the DTS test and into dumbbell-shaped molds for the UTS test. Inside the molds, the cements were light-activated either immediately or after 5 min (delayed light activation). If no light activation was performed, the materials were protected from light exposure (control). The DTS and UTS tests were performed until fracture. The elastic modulus was calculated using data from the DTS test, and DC was evaluated 24 h after manipulation using near-infrared spectroscopy. Data for each variable were individually analyzed by two-way ANOVA and the post-hoc Tukey test (α = 0.05). Regarding DTS, activation mode influenced only Panavia Fspecimens, which had the lowest DTS values in the absence of light activation. Activation mode did not influence the elastic modulus or UTS of any resin cement evaluated. Immediate light activation yielded higher DC values as compared with the absence of light activation.

Nanoparticle loading level and properties of experimental hybrid resin luting agents.

PURPOSE: This study investigated the influence of nanoparticle loading level on properties of experimental hybrid resin luting agents. MATERIALS AND METHODS: Silanated 2-µm barium borosilicate glass microparticles and 7-nm silica nanoparticles were used. Five materials were obtained by loading a photocurable Bis-GMA/TEGDMA co-monomer with a total mass fraction of 60% inorganic fillers. The mass fraction of nanoparticles was set at 0% (control), 1% (G1), 2.5% (G2.5), 5% (G5), or 10% (G10). The properties evaluated were flexural strength (σ) and modulus (E(f) ), Knoop hardness number (KHN), and film thickness (FT). Dispersion/interaction of the particles with the resin phase was assessed by scanning electron microscopy (SEM). Data were submitted to statistical analysis (5%). RESULTS: For σ, G1 > G2.5 = G5 = G10, and control > G10. For E(f) , G2.5 > control = G1 > G5 > G10. For KHN, G5 = G10 > control = G1 = G2.5. For FT, G10 = G5 > control = G1, and G10 > G2.5. Incorporation of nanoparticles was associated with observation of clusters in the SEM analysis. The clusters were more frequent for higher nanoparticle loadings. CONCLUSION: Modest incorporation of nanoparticles may improve the properties of resin luting materials. Nanofiller mass fractions above 2.5% should, however, be avoided because they may be detrimental to the properties of the resin luting agents.

Hybridization morphology and dentin bond stability of self-etch primers with different ethanol/water ratios.

This study evaluated the influence of ethanol/water ratios on the bond strength to dentin of experimental two-step, self-etch adhesive systems. Self-etch primers were prepared with constant 40 mass % of solvents. The ethanol/water ratios tested were 7:1 (P1), 3:1 (P2), and 1:1 (P3); primers with only ethanol (PE) or water (PW) as solvent were also tested. The bond strength to the dentin was investigated through a microtensile bond strength test. Resin-dentin beam-shaped specimens were obtained and tested after 24 h, 6 months, and 1 year of storage in water at 37°C. The hybridization morphology was analyzed using SEM. For bond strength at 24 h, PE = P1, P1 = P2, and P2, P3 and PW > PE. After 6 months, PE = P1 < P2, P3 and PW. After 1 year, no significant differences among the materials were detected. No significant differences among the periods were detected for PE. For P1, 24 h > 6 months = 1 year. For P2, P3 and PW, 24 h = 6 months > 1 year. For PE and P1, adhesive failures were predominant at 24 h, mixed or adhesive failures after 6 months, and premature debonding was predominant after 1 year. For P2, mixed failures were predominant at 24 h and 6 months, and premature debonding after 1 year. For P3 and PW, mixed failures were predominant at all storage periods. The SEM analysis revealed no clear differences in the hybridization patterns yielded by the water-based primers; PE showed formation of irregular resin tags.

Programa de diagnóstico e prevenção de câncer de boca: uma estratégia simples e eficaz / Program diagnosis and prevention of oral cancer: a simple and effective strategy

O programa de diagnóstico e prevenção de câncer de boca do Univag - Centro Universitário, elaborado pelos docentes da disciplina de Diagnóstico em Odontologia, visa ao incremento de ações preventivas e precoces das doenças bucais com ênfase no câncer bucal, buscando reduzir os índices de morbi-mortalidade através de palestras educativas, divulgação do auto-exame, realizadas pelos acadêmicos de odontologia do Univag desde o segundo semestre de 2005 até os dias atuais. Os acadêmicos de odontologia dos 1º, 2º, 3º e 4º semestres foram capacitados através de aulas teórico-práticas, para a realização de exames preventivos e diagnósticos, como o auto-exame, citologia esfoliativa e biópsia da mucosa bucal, e ainda para a apresentação de palestras educativas. Analisando-se os resultados preliminares foi constatado incremento no número de diagnósticos e encaminhamento de pacientes diagnosticados com câncer bucal para os serviços de referência. Concluiu-se que programa de diagnóstico e prevenção de câncer de boca possibilita o diagnóstico precoce e adoção de medidas de prevenção, e, consequentemente aumento da sobrevida e qualidade de vida da população acometida.

The program of diagnosis and prevention of oral cancer of Univag - University Center aims to increase preventive and early oral diseases with emphasis on oral cancer, aiming to reduce the morbidity and mortality through educative actions, spreading of the auto-examination, performed by dental students of UNIVAG since the second half of 2005 to the present day. The dental students of 1st, 2nd, 3rd and 4th semesters were trained using practice-theoretical classes, for realization the exams preventives and diagnostics, such as self-examination, exfoliative cytology and biopsy of oral mucosa, and even present educative actions. Analyzing the preliminary results were observed increase in the number of diagnoses and referral of diagnosed with oral cancer for treatment in referral services. It was concluded that the program of diagnosis and prevention of oral cancer can make possible early diagnosis and adoption of preventive measures, consequently improving survival rates and life quality in population.

Tetrahydrofuran as alternative solvent in dental adhesive systems.

OBJECTIVE: To evaluate the influence of tetrahydrofuran (THF) on the resin-to-dentin microtensile bond strength (microTBS) after water storage, for 24h and 6 months, and to compare its behavior with that of traditional solvents. METHODS: Seven versions of monomer/solvent mixtures (primers) were prepared using the following solvent and water combinations: (1) THF, (2) acetone, (3) ethanol, (4) water, (5) THF/water, (6) acetone/water and (7) ethanol/water. An experimental adhesive resin was also synthesized to compare adhesive systems with the different primers. Forty-two bovine incisors, randomly separated into seven groups, had their superficial coronal dentin exposed. After acid-etching and rinsing, the excess water was removed from the surface with absorbent paper. Each experimental primer was applied with agitation (30s) followed by a mild air stream (10s). The experimental adhesive resin was applied and light-activated (20s). Resin composite restorations were constructed incrementally. Restored teeth were stored in distilled water at 37 degrees C (24h) and sectioned to obtain sticks with an area of 0.5mm(2). Half the specimens were subjected to the microTBS test immediately after being cut and the other half were tested after 6 months of water storage. Data (MPa) were analyzed by two-way ANOVA (solvent type and storage time as factors) and Tukey-Kramer's test at alpha=0.05. RESULTS: Factors and interaction showed a statistical effect. After 6 months storage, acetone groups and primers containing THF showed similar microTBS to initial means. SIGNIFICANCE: THF seems to be a promising solvent for use in dental adhesive systems, maintaining bond strength on dentin substrate after storage.

Onium salt reduces the inhibitory polymerization effect from an organic solvent in a model dental adhesive resin.

This study evaluated the effect of organic solvent concentration on the polymerization kinetics for a model dental adhesive resin containing a ternary photoinitiator system. A monomer blend based on the bis-GMA, TEGDMA, and HEMA was used as a model dental adhesive resin, which was polymerized using a binary system [camphorquinone (CQ) and ethyl 4-dimethylamine benzoate (EDAB)] and a ternary system [CQ, EDAB, and diphenyliodonium hexafluorphosphate (DPIHFP)]. Additionally, these blends had 0, 10, 20, 30, and 40 wt % ethanol added. Real-time Fourier transform infrared spectroscopy was used to investigate the polymerization reaction over photoactivation time. Data were plotted, and Hill's three-parameter nonlinear regression was performed for curve fitting. The addition of a solvent to the monomer blends decreased the polymerization kinetics, directly affecting the rate of polymerization, delaying vitrification, and attenuating the Trommsdorf effect. The introduction of DPIHFP displayed a strong increase in reaction kinetics, reducing the solvent inhibition effect. After 10 s of photoactivation, the binary system obtained in 0, 10, 20, 30, and 40% of ethanol, a degree of conversion of 44.6, 26.3, 13.4, 1.15, and 0.0%, respectively, whereas when a ternary system was used, the values were 54.6, 40.5, 27.4, 14.5, and 3.4%. An improvement was observed in the polymerization kinetics of a model dental adhesive resin when using a ternary photoinitiation system, making the material less sensitive to the residual presence of a solvent before photoactivation.