Is immediate dentin sealing a mandatory or optional clinical step for indirect restorations?

OBJECTIVE: The use of immediate dentin sealing (IDS) following tooth preparation for indirect restorations is well-supported by laboratory studies. The inclusion of IDS as a mandatory clinical step, it must be firmly supported by evidence from randomized clinical trials (RCT). The objective of this study is to assess whether IDS should be added as a mandatory procedure in all indirect restorations, taking into consideration clinically significant outcomes for the patient, such as restoration longevity and hypersensitivity. MATERIALS AND METHODS: A bibliographic search was carried out in the PubMed. In addition, a manual search was conducted in the references of literature reviews. RESULTS: Data from four RCT were included. Two studies assessed preparations for full crowns, and two assessed preparations for partial restorations. Data from full crown preparations were subjected to a meta-analysis, revealing a reduction in hypersensitivity incidence in the IDS group 1 week after restoration cementation. With respect to hypersensitivity, IDS seems to offer advantages exclusively during the provisional phase and up to 1 week following the cementation of the final restoration. One study has shown no difference on longevity. CONCLUSION: The use of IDS should be considered as an elective clinical step during the rehabilitation with indirect restorations. CLINICAL SIGNIFICANCE: IDS is an elective clinical step that should be considered in patients and preparations with a higher risk of sensitivity between appointments.

Color variation of composite resins in relation to the Vita Classical shade guide: colorimetric analysis

Aim: The aim of this study was to verify the color variation between different composite resins and the Vita Classical Shade Guide. Methods: Two-millimeter thickness samples were made (n = 6) from eight commercial brands of composite resin (shade A2): Charisma (Kulzer), Forma (Ultradent), Harmonize (Kerr), Luna (SDI), Opallis (FGM), Oppus Bulk Fill (FGM), Vittra (FGM) and Filtek Z250 XT (3M ESPE). Specimens were stored in distilled water for 7 days and then polished. Color measurements of samples and A2 shade of the Vita Classical Shade Guide were performed using the Vita Easy Shade Advance 4.0 spectrophotometer on a black background. Color variations were calculated using the CIEDE2000 formula, considering values ≥0.81 being noticeable by the human eye and ≥1.77 being clinically unacceptable. Results were statistically analyzed with a 5% significance level. Results: Color variation (ΔE) of composite (E1 ) compared to the Vita Classical Shade Guide (E0 ) was greater than clinically acceptable for all the materials evaluated in this study. Forma (ΔE=2.08 ± sd=0.47) and Filtek Z250 XT (2.50 ± 0.20) had the smallest amount of color variation values found in the results. Harmonize (3.32 ± 0.63) presented values similar to Filtek Z250 XT, but it was worse than Forma. Vittra (3.51 ± 0.28), Charisma (3.80 ± 0.20), Opallis (4.24 ± 0.30) and Luna (5.67 ± 0.20) did not differ among each other and presented higher color variation than Forma, Filtek Z350XT and Harmonize. Oppus Bulk Fill (13.94 ± 1.12) was the composite with the greatest color variation. Conclusions: The findings in this study show that attention should be taken when using the Vita Color Shade Guide for composite shade selection

Influence of the incorporation of titanium dioxide nanofibers net on bond strength and morphology of a total etching adhesive system.

Background: The aim of this study was to evaluate the nanoleakage and microtensile bond strength (µTBS) of an ethanol based-adhesive containing Titanium dioxide (TiO2) nanofibers to dentin. Material and Methods: TiO2 nanofiber was produced by electrospinning and it was inserted in an ethanol-based adhesive in 0.5, 1.5 and 2.5% by weight. The original adhesive did not receive nanofiber. The middle dentin was exposed by diamond saw under water-cooling and dentin was polished with wet 600-grit SiC abrasive paper. Resin composite build-ups were applied incrementally to the dentin after adhesive application. After storage in distilled water (24 hours/37°C) the teeth were sectioned perpendicularly to the bonded interface and sticks were obtained. Twenty-five sticks per group were tested by µTBS with a crosshead speed of 0.5mm/minute. The average values (MPa) obtained in each substrate were subjected to one-way ANOVA (α=0,05) with the tooth being considered the experimental unit. The nanoleakage pattern was observed in ten sticks per group and analyzed by Chi-square test (α=0,05). Results: There was no difference in µTBS among the experimental groups. However, there was a statistically significant difference among 2.5 % nanofiber adhesive, 0.5 % nanofibers and control groups, (p=0,028) in relation to nanoleakage. Conclusions: TiO2 nanofibers in 2.5% of weight inserted in dental adhesive reduced the nanoleakage, but did not improve the µTBS to dentin. Key words:Dentin-bonding agents, nanoleakage, tensile bond strength.

Bibliometric analysis and diagnostic efficacy of cone-beam computed tomography studies published in Imaging Science in Dentistry from 2011 to 2022.

Purpose: This bibliometric analysis aimed to provide a comprehensive overview of the characteristics, trends, and level of diagnostic efficacy of studies on cone-beam computed tomography (CBCT) published in Imaging Science in Dentistry (ISD) from 2011 to 2022. Materials and Methods: Publications related to CBCT identified in the electronic collection of ISD were selected according to eligibility criteria by 2 independent reviewers who collected data on the characteristics of the articles (year, authors, and country). The type and topic of studies were analyzed using VOSviewer v.1.6.18 (Centre for Science and Technology Studies, Leiden University, Leiden, Netherlands). The research articles were classified according to the hierarchical scale of diagnostic efficacy. Results: Of the 236 articles included, most were from South Korea and Brazil. Bong-Hae Cho and Yun-Hoa Jung were the most prolific authors on the topic of CBCT. The most frequently published types of studies were cross-sectional and laboratory-based. The most popular topics WERE related to the diagnosis of pathologies and/or alterations, as well as anatomical variations. On the diagnostic efficacy scale, most studies were rated level 1 (technical efficacy) or 2 (diagnostic accuracy efficacy). Conclusion: A steady increase was observed in publications related to CBCT, which are of both clinical and academic interest. The trends in these publications were analyzed, revealing that most are cross-sectional studies primarily exploring the capabilities of CBCT in diagnosing pathologies and/or changes in the oral and maxillofacial complex. These studies were typically classified as level 1 or 2 on the diagnostic efficacy scale.

Reuse of healing abutments: Ethical, biological and professional training implications.

Background: The aim was to estimate the prevalence of reuse of healing abutments, the methods used in disinfection and to analyze the reasons that lead to the reuse of these components by professionals who work in rehabilitation with dental implants. Material and Methods: For this, an online data collection was carried out through a questionnaire developed in Google Forms. This questionnaire was applied to 284 specialists in implantology, randomized, of the 1,147 registered in the Regional Council of Dentistry of Rio Grande do Sul. The questionnaire was divided into three parts: the first containing the Free and Informed Consent Form; the second referring to the correspondents' demographic data; and the third part with information on reuse, disinfection and sterilization routines used, risk perception and information from manufacturers. To estimate the prevalence in the reuse of healing abutments by implantologists, the frequency of responses was used. Results: The results showed that almost all implantologists reuse healing abutments (98.1%). The main reasons for reuse were cost (71.2%) and practicality (26%). Regarding the limitations, 53.3% do not see limitations in its reuse, 20% associate it with increased roughness, 17.8% with the accumulation of organic matter and 8.9% with cross-infection as limitations for reuse. Already 95.3% did not receive any guidance from manufacturers on the reuse of these components. Enzymatic detergent and ultrasonic bath was the most used cleaning method (50.7%) followed by ultrasonic bath (23.3%). Autoclave was the method used for sterilization for all respondents. Conclusions: The reuse of healing abutments is a practice adopted by implantologists in the state of Rio Grande do Sul, Brazil and most professionals do not observe limitations in this practice since these components are used repeatedly. Decontamination with enzymatic detergent and an ultrasonic bath is the most commonly used procedure associated with autoclave sterilization. Key words:Abutment, reuse, decontamination, sterilization.

Experiências e percepções de discentes e docentes de odontologia sobre as aulas remotas durante a pandemia de COVID-19 / Experiences and perception of dentistry students and professors regarding online classes during the COVID-19 pandemic

O presente estudo objetivoudescrever a percepção de docentes e discentes de Odontologia sobre as atividades desenvolvidas nos ambientes virtuaisde aprendizagemdurante o período de isolamento social. Professores e estudantes dequatro cursosde Odontologia foram convidados a responderaum questionário autoaplicável, contendo questões objetivas e subjetivas arespeito de suas experiências e sensações em relação às atividades.Tanto docentes quanto discentes consideram que o aprendizado nesse período foi inferior ao presencial, contudo, concordam com a manutenção das aulas virtuais durante o período da pandemia (AU).

The present study aimed to describe the perception of Dentistry professors and students regarding the activities developed in virtual environments during the period of social isolation. Through self-administered questionnaires, professors and students from four Dentistry courses were invited to answer objective and subjective questions about their experiences and sensations during the period. Both professors and students consider that the learning in this period was inferior to the face-to-face, however, they agree with the maintenance of the virtual classes during the pandemic period (AU).

Cytotoxicity assessment of Bio-C Repair Íon+: A new calcium silicate-based cement.

Background. Direct pulp capping is a method designed to preserve the exposed dental pulp. Due to good biological, physical, and mechanical properties, new versions of calcium silicate-based materials have been developed as pulp capping materials. The present study aimed to evaluate the cytotoxic effects of four calcium silicate-based pulp capping materials, of which the Bio-C Repair Íon+ is still in an experimental phase. Methods. Biodentine, MTA Repair HP, Bio-C Repair, and Bio-C Repair Íon+ cements were dispensed in a metallic matrix to produce 125-mm3 specimens, which were immersed in Dulbecco's Modified Eagle Medium (DMEM) to obtain extracts. NIH 3T3 cells were cultured and exposed to the extracts for 24 hours and seven days. Cell viability was assessed by the methyl tetrazolium test (MTT). The mean values for the experimental and control groups (without treatment) were compared by analysis of variance (ANOVA) and post hoc Tukey tests, considering a significance level of 5%. Results. All the tested materials demonstrated a reduction in cell viability (P < 0.05). According to ISO 10993-5: 2009 (E), Bio-C Repair Íon+ exhibited mild and moderate cytotoxicity in the 24- hour and 7-day analyses, respectively. Bio-C Repair and Biodentine showed mild cytotoxicity, and MTA Repair HP exhibited moderate cytotoxicity at both intervals. Conclusion. The highest cell viability was demonstrated by Biodentine, MTA, and Repair HP, in descending order. Bio-C Repair and Bio-C Repair Íon+ showed moderate cytotoxicity, similar to MTA Repair HP in the 7-day analysis.

Efetividade da ozonioterapia contra microrganismos endopatogênicos: revisão de literatura / Effectiveness of ozone therapy against endopathogenic microorganisms: literature review

Introdução: A comunidade científica está em constante busca por alternativas terapêuticas que promovam a desinfecção dos canais radiculares. Dentre os diversos protocolos existentes, a terapia com o ozônio tem se mostrado uma técnica viável para tal finalidade. Assim, o objetivo da presente revisão de literatura é descrever a efetividade da ozonioterapia na redução de microrganismos endopatogênicos. Revisão de literatura e discussão: A literatura apresenta, em sua maioria, estudos laboratoriais e carece de estudos clínicos sobre o tema. Esses estudos demonstram que o ozônio líquido e gasoso possui propriedades antimicrobianas e é eficiente na desinfecção do sistema de canais radiculares. No entanto, devido aos diferentes protocolos de utilização da ozonioterapia, associado às diferenças metodológicas dos estudos, pode-se afirmar que a ozonioterapia parece ser eficiente na desinfecção dos canais radiculares, mas há controvérsias sobre a sua utilização como técnica complementar ou substituta às soluções irrigadoras tradicionais. Conclusão: Ainda não é possível afirmar que o ozônio pode ser um substituto ao hipoclorito de sódio. No entanto, alguns autores relatam que o ozônio pode ser utilizado como um agente coadjuvante na redução de microrganismos presentes nos canais radiculares e é uma alternativa viável para os casos em que o hipoclorito de sódio está contraindicado.

Introduction: The scientific community is in constant search for therapeutic alternatives that promote the disinfection of root canals. Among the various existing protocols, ozone therapy has been shown to be a viable technique for this purpose. Thus, the aim of the present literature review is to describe the effectiveness of ozone therapy on reduction of endopathogenic microorga-nisms. Literature review and discussion: Most part of the literature presents in vitro and clinical studies on the subject and demonstrate that the liquid and gaseous ozone have antimicrobial properties and are efficient in disinfecting the root canal system. However, due to the different protocols for ozone therapy use associated with the methodological differences from the studies, it can be indicated that ozone therapy seems to be an efficient disinfection of root canals, but there are controversies about its use as a complementary or substitute technique in place of traditional irrigation solutions. Conclusion:It is not yet possible to consider ozone as a substitute for hypochlorite sodium. However, some authors report that ozone can be used as a supporting agent on reduc-tion of microorganisms present in the root canals and a viable alternative for cases in which hypochlorite is contraindicated.

Influência do polimento na estabilidade de cor de uma resina composta após imersão em diferentes substâncias corantes / Influence of polishing on color stability of a composite resin after immersion in different coloring substances

Objetivo: Avaliar o grau de pigmentação da resina composta imersa em água destilada, molho shoyu e vinho tinto, submetida a diferentes métodos de polimento. Método: Foram confeccionadas 90 espécimes de resina composta cor A2 esmalte (4 mm de diâmetro de topo, 3 mm de diâmetro de fundo e 2 mm de espessura), divididos igualmente em três grupos, de acordo com o tratamento superficial realizado (sem polimento, polimento com Diamond Pro e polimento com lixa). As 30 amostras de cada grupo foram divididas em três subgrupos (n=10) e imersas em diferentes soluções (água, molho shoyu e vinho tinto). A análise colorimétrica foi realizada previamente, 7 e 15 dias após a imersão das amostras nas soluções, com o auxílio de um colorímetro. Os dados foram submetidos aos testes de ANOVA/Tukey considerando um nível de significância de 5%. Resultados: Amostras imersas em água apresentaram pequena variação de cor (E=2,2), com exceção das que não receberam polimento (E=7,8). O vinho tinto apresentou significativo maior potencial de pigmentação (E=15), independente do método de polimento, enquanto o molho shoyu (E=11) demonstrou pigmentar com maior intensidade as amostras polidas com discos de lixa. Conclusões: É necessário fazer um acabamento e um polimento adequado na restauração de resina composta para que o grau de pigmentação seja o menor possível. Sobre os alimentos corantes, conclui-se que tanto o molho shoyu quanto o vinho tinto pigmentam a resina composta, porém o vinho pigmenta com uma intensidade maior(AU)

Objective: To evaluate the degree of pigmentation of composite resin immersed in distilled water, shoyu sauce and red wine, with different polishing methods. Method: 90 specimens of A2 enamel composite resin (4 mm of top diameter, 3 mm of bottom diameter and 2 mm of thickness) were made, equally divided into three groups, according to the surface treatment carried out (without polishing, polishing with Diamond Pro and polishing with sandpaper). The 30 samples from each group were divided into three subgroups (n = 10) and immersed in different solutions (water, shoyu sauce and red wine). The colorimetric analysis was performed previously, 7 and 15 days after the samples immersion in the solutions, with the aid of a colorimeter. The data were submitted to ANOVA/Tukey tests considering a significance level of 5%. Results: Samples immersed in water showed little color variation (E = 2.2), with the exception of those that did not receive polishing (E = 7.8). Red wine showed a significant higher pigmentation potential (E = 15), regardless of the polishing method, while shoyu sauce (E = 11) demonstrated to pigment the polished samples with sandpaper with greater intensity. Conclusion: It is necessary to finish and polish the composite resin properly so that the degree of pigmentation is as low as possible. Regarding coloring foods, it is concluded that both shoyu sauce and red wine pigment the composite resin, but the wine pigments with greater intensity(AU)

Effect of preheating on cytotoxicity and physicochemical properties of light-cured calcium-based cements.

The aim of this study was to evaluate the degree of conversion, cytotoxicity, solubility and pH of photopolymerizable calciumbased cements submitted to preheating. The degree of conversion was analyzed by Fourier transform infrared, cytotoxicity by the MTT test and solubility through loss of mass. The data were subjected to statistical tests (ANOVA / Tukey's, p<0.05). The photopolymerizable materials showed a low degree of conversion, regardless of preheating. All materials caused a reduction in cell viability at 24 hours and 7 days, with the Dycal (control) being more cytotoxic. Heat had a positive effect on Biocal at 7 days. Dycal is the most soluble material. Heat had no effect on the solubility or pH of the polymerizable materials. It is concluded that photopolymerizable calcium-based cements have a low degree of conversion and are soluble, which results in mild to moderate cytotoxicity.

O objetivo do presente estudo foi avaliar o grau de conversão, citotoxicidade, solubilidade e pH de cimentos à base de cálcio fotopolimerizáveis submetidos a pré-aquecimento. O grau de conversão foi analisado por espectroscopia no infravermelho com transformada de Fourier, a citotoxicidade pelo teste de MTT e a solubilidade através da perda de massa. Os dados foram submetidos a testes estatísticos (ANOVA/Tukey, p<0,05). Os materiais fotopolimerizáveis apresentaram baixo grau de conversão, independente do pré-aquecimento. Todos os materiais causaram redução da viabilidade celular nas análises de 24 horas e 7 dias, sendo que o Dycal (controle) apresentouse mais citotóxico e o calor apresentou efeito positivo sobre o Biocal na análise de 7 dias. O Dycal é o material mais solúvel e o calor não causou efeito na solubilidade e pH dos materiais polimerizáveis. Assim, conclui-se que os cimentos à base de cálcio fotopolimerizáveis apresentam baixo grau de conversão e são solúveis, que resulta em citotoxicidade suave e moderada.

Effect of preheating on cytotoxicity and physicochemical properties of light-cured calcium-based cements / Efeito do pré-aquecimento na citotoxicidade e propriedades físico-químicas de cimentos à base de cálcio fotopolimerizáveis

ABSTRACT The aim of this study was to evaluate the degree of conversion, cytotoxicity, solubility and pH of photopolymerizable calciumbased cements submitted to preheating. The degree of conversion was analyzed by Fourier transform infrared, cytotoxicity by the MTT test and solubility through loss of mass. The data were subjected to statistical tests (ANOVA / Tukey's, p<0.05). The photopolymerizable materials showed a low degree of conversion, regardless of preheating. All materials caused a reduction in cell viability at 24 hours and 7 days, with the Dycal (control) being more cytotoxic. Heat had a positive effect on Biocal at 7 days. Dycal is the most soluble material. Heat had no effect on the solubility or pH of the polymerizable materials. It is concluded that photopolymerizable calcium-based cements have a low degree of conversion and are soluble, which results in mild to moderate cytotoxicity.

RESUMO O objetivo do presente estudo foi avaliar o grau de conversão, citotoxicidade, solubilidade e pH de cimentos à base de cálcio fotopolimerizáveis submetidos a pré-aquecimento. O grau de conversão foi analisado por espectroscopia no infravermelho com transformada de Fourier, a citotoxicidade pelo teste de MTT e a solubilidade através da perda de massa. Os dados foram submetidos a testes estatísticos (ANOVA/Tukey, p<0,05). Os materiais fotopolimerizáveis apresentaram baixo grau de conversão, independente do pré-aquecimento. Todos os materiais causaram redução da viabilidade celular nas análises de 24 horas e 7 dias, sendo que o Dycal (controle) apresentouse mais citotóxico e o calor apresentou efeito positivo sobre o Biocal na análise de 7 dias. O Dycal é o material mais solúvel e o calor não causou efeito na solubilidade e pH dos materiais polimerizáveis. Assim, conclui-se que os cimentos à base de cálcio fotopolimerizáveis apresentam baixo grau de conversão e são solúveis, que resulta em citotoxicidade suave e moderada.

Effect of heat treatment on cytotoxicity and polymerization of universal adhesives.

To assess, in vitro, the influence of heat air treatment on cytotoxicity and degree of conversion (DC) of universal self-etch adhesives (Ambar Universal APS, Scotchbond Universal Adhesive, and Tetric N-Bond Universal) in an NIH/3T3 fibroblast cell culture. Samples were divided into three groups: 1) no heat treatment (control), 2) 37°C and 3) 60°C heat treatment before photopolymerization. Cytotoxicity was analyzed by MTT assay and the DC by FTIR. All adhesives heated at 60°C showed reduced cytotoxicity levels when compared with those heated at 37°C. In general, DC of Ambar Universal APS presented the highest DC than Scotchbond Universal Adhesive and Tetric N-Bond Universal, and the hot air treatment do not influence the conversion. Heat treatment at 60°C was able to reduce the cytotoxicity of universal self-etch adhesives, even, the heat treatment does not enhances the DC.

Hot air stream reduces cytotoxicity of light-cured calcium hydroxide based cements.

BACKGROUND: The light-cured calcium hydroxide based cements have incomplete polymerization and unconverted monomers can cause pulp cell damage. The aim of this study was to evaluate the influence of a warm and hot air stream on the cytotoxicity of light-cured calcium hydroxide based cements. MATERIAL AND METHODS: The materials Dycal (conventional cement), Biocal, Hidrox-Cal, and Ultra-Blend Plus (light-cured calcium hydroxide cements) were submitted to cytotoxicity analysis after polymerization, without vs. with previous heat treatment with a warm (37°C) and a hot (60°C) air stream. Following polymerization, cements were maintained in culture medium for 24 hours and 7 days, and subjected to the MTT test. Data were analyzed using analysis of variance (ANOVA) followed by post-hoc Student-Newman-Keuls (<0.05). RESULTS: The results indicated significant differences between the materials according to their composition, i.e., light-cured cements treated with a jet of warm air showed similar cytotoxicity levels to those observed for conventional cement, suggesting that they may be considered alternatives in cases requiring pulp-capping treatment. CONCLUSIONS: Application of a hot air stream reduced cytotoxicity of materials tested. Key words:Dental pulp capping, dental cements, calcium hydroxide, cell survival.

O papel das mídias sociais na construção do conhecimento em Odontologia / The role of social media in the construction of knowledge in Dentistry

Este artigo, de cunho teórico, discute a construção do conhecimento em Odontologia no contexto da Sociedade em Rede, aproximando essa temática ao ponto de vista de alguns autores das Ciências Sociais Contemporâneas em voga. A bibliografia especializada aponta que a sociedade vive em uma constante transformação. Prova disso é que a construção de conhecimento pedagógico em Odontologia se dá hoje com maior intensidade na internet, principalmente nas mídias sociais, do que através da busca em livros. Por essa nova forma de agregar conhecimento ser uma realidade, é de fundamental importância que pessoas qualificadas sejam vetores de transmissão desses conhecimentos, de uma forma didática e com embasamento científico. Além disso, cabe aos professores se adaptarem ao novo estilo de construção do conhecimento pedagógico, elaborando aulas mais interativas e com o auxílio de ferramentas que chamem a atenção dos seus alunos e, concomitante a isso, ofereçam-lhes informações de qualidade.

This theoretical article discusses the construction of knowledge in dentistry in the context of the Network Society, bringing this theme closer to the point of view of some contemporary Social Science writers, nowadays in vogue. The specialized bibliography indicates that the society lives in a constant transformation, proof of this is that the construction of pedagogical knowledge in dentistry occurs today with greater intensity in the internet, mainly in the social media, than through the search in books. Because this new form of knowledge aggregation is a reality, it is of fundamental importance that qualified people are vectors of transmission of this knowledge, in a didactic and scientific basis. In addition, it is up to teachers to adapt to the new style of construction of pedagogical knowledge, developing more interactive classes and with the help of tools that attract the attention of their students and, at the same time, offer them quality information.

Effect of heat treatment on cytotoxicity of self-adhesive resin cements: Cell viability analysis.

OBJECTIVE: The aim of the study was to assess, in vitro, the influence on cytotoxicity of heat treatment applied before photopolymerization, while mixing three self-adhesive resin cements, in an NIH/3T3 fibroblast cell culture, based on cell viability measures. METHODS: Samples were divided into three groups: (1) no heat treatment while mixing (control), (2) 37°C, and (3) 60°C heat treatment while mixing. Cements were light-cured immediately after mixing and immersed in Dulbecco's Modified Eagle Media for the extraction of possibly uncured products after 24 h and 7 days. Cultures contained 0.5 mL of NIH/3T3 fibroblasts per well at a concentration of 0.4 × 105 cells/mL and specific extracts for each sample. STATISTICAL ANALYSIS USED: Data were statistically analyzed with ANOVA and post hoc Student-Newman-Keuls (significance of 5%). RESULTS: Cement cytotoxicity increased with time, as shown by the higher values observed at 7 days. There was a slight difference in intragroup cytotoxicity levels between 24 h and 7 days. Heat treatment at 60°C was associated with a major decrease in cytotoxicity levels in all three groups, both at 24 h and at 7 days, with no differences among the cements. CONCLUSIONS: Heat treatment at 60°C should be considered as a strategy to reduce cytotoxicity of self-adhesive resin cements, as evidenced by the results observed at 24 h and 7 days of analysis.

Effect of At-home and In-office Bleaching on Marginal Microleakage in Composite Resin Restorations using Two Adhesive Systems.

AIM: The aim of this study is to assess marginal microleakage of cervical cavities restored with composite resins and two different adhesive techniques subjected to at-home and in-office bleaching. MATERIALS AND METHODS: In this randomized, blind laboratory experiment, 60 bovine teeth recently extracted were collected and divided into six groups (n = 10 each group). The teeth received cervical cavity preparations (2 mm × 3 mm × 1 mm) with enamel margins. Two different adhesive systems were used (Single Bond 2 and Clearfil SE Bond), in addition to composite resin (Z250). Restored teeth received two different bleaching gels (Opalescence PF and Opalescence Boost). Teeth were thermo-cycled and analyzed under confocal laser scanning microscopy. RESULTS: No significant differences were observed (p > 0.05) in microleakage scores between the two groups not subjected to bleaching nor between the four groups that received bleaching treatment (p > 0.05), regardless of the gel and adhesive system employed. However, when comparing nonbleached with bleached teeth, those not subjected to bleaching showed statistically lower marginal microleakage scores (p < 0.05). Data were statistically analyzed using the Kruskal-Wallis test followed by Student-Newman-Keuls post hoc test, with significance set at 5%. CONCLUSION: Marginal microleakage in composite resin restorations is influenced by the action of bleaching agents used both at-home and in-office, regardless of the adhesive system employed (total-etch or self-etch). CLINICAL SIGNIFICANCE: Both at-home and in-office bleaching agents have an influence on the adhesive interface of resin restorations, producing changes and inducing marginal leakage.