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BACKGROUND: The objective of this study was to evaluate the effect of bleaching techniques, including or not the use of violet light (405-410 nm), on resin-based composites' color, surface roughness, nanohardness, and elastic modulus. METHODS: Ninety-six disk-shaped specimens (12 mm x 2 mm; n = 12) were prepared using Filtek Z350 XT (Z350) and IPS Empress Direct (ED) resin-based composites. After 24 h, specimens were stained in red wine for 28 days. After staining, specimens were divided into four experimental groups: 40 % Hydrogen Peroxide (HP); Violet Light (VL); 40 % Hydrogen Peroxide associated with Violet Light (HP+VL), and a control group - no treatment (NT). Specimens were evaluated at six experimental times: initial (24 h after light curing); after staining and after the 1st, 2nd, 3rd, and 4th bleaching sessions regarding the color change (ΔE00, L*, a*, b*, and WID); roughness (Ra), nanohardness and elastic modulus (GPa). Two-way analysis of variance for repeated measures was performed (α=0.05 %). RESULTS: There was a statistically significant difference between staining and the 1st bleaching session for all ED groups (p<0.05). After the last bleaching session, there were no differences between the experimental and the control groups of both resin-based composites. Bleaching using violet light did not change the roughness, nanohardness and elastic modulus of the tested resin-based composites (p>0.05). CONCLUSIONS: Although hydrogen peroxide and violet light remove pigments from resin-based composites without affecting their surface roughness, nanohardness, and elastic modulus, the color change was similar to the one obtained by immersion in distilled water.

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Objectives: This study verified the possibility of cementing fiberglass-reinforced posts using a flowable bulk-fill composite (BF), comparing its push-out bond strength and microhardness with these properties of 3 luting materials. Materials and Methods: Sixty endodontically treated bovine roots were used. Posts were cemented using conventional dual-cured cement (CC); self-adhesive cement (SA); dual-cured composite (RC); and BF. Push-out bond strength (n = 10) and microhardness (n = 5) tests were performed after 1 week and 4 months of storage. Two-way repeated measures analysis of variance (ANOVA), 1-way ANOVA, t-test, and Tukey post-hoc tests were applied for the push-out bond strength and microhardness results; and Pearson correlation test was applied to verify the correlation between push-out bond strength and microhardness results (α = 0.05). Results: BF presented higher push-out bond strength than CC and SA in the cervical third before aging (p < 0.01). No differences were found between push-out bond strength before and after aging for all the luting materials (p = 0.84). Regarding hardness, only SA presented higher values measured before than after aging (p < 0.01). RC and BF did not present 80% of the maximum hardness at the apical regions. A strong positive correlation was found between the luting materials' push-out bond strength and microhardness (p < 0.01, R2 = 0.7912). Conclusions: The BF presented comparable or higher push-out bond strength and microhardness than the luting materials, which indicates that it could be used for cementing resin posts in situations where adequate light curing is possible.

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INTRODUCTION: Studies defining the characteristics of light curing units and photoactivation methods are necessary to allow the correct choices to be made in daily practice. This study aimed to determine whether different photoactivation protocols for composite resins [periodic level shifting (PLS) - 5 second and soft-start] are able to maintain or enhance the mechanical properties and marginal adaptation of restorations. METHODS: Restorations were placed in bovine teeth using the following photoactivation methods: continuous light for 20 seconds (control group); PLS technology (PLS - 5 second group); and continuous light and a light guide tip distance of 6 mm after which the tip was placed at the surface of the restoration (soft-start group). The teeth were transversely sectioned in the incisal-cervical direction. Thirty halves were randomly selected for Knoop microhardness testing (n = 10). The other 30 halves were subjected to scanning electron microscopy analysis. The images obtained were measured to identify the highest marginal gap, and statistical tests for variance analysis were conducted. RESULTS: Microhardness tests showed no statistically significant difference between the photoactivation methods analysed (P ≥ 0.01). The tests showed a difference among depths (P < 0.01), with the deeper layers being the hardest. In analysing marginal adaptation, no significant difference was identified between the higher marginal gap values in the continuous (mean = 10.36) and PLS - 5 second (mean = 10.62) groups, and the soft-start group (mean = 5.83) presented the lowest values (P < 0.01). CONCLUSIONS: The PLS - 5 second and soft-start protocols did not alter the hardness of the restorations. Moreover, the PLS - 5 second protocol did not alter the marginal adaptation, whereas the soft-start protocol improved marginal adaptation.

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Objetivo: Determinar, dentre os profissionais de Odontologia, o grau de formação e informação quanto ao uso da tomografia computadorizada tipo cone-beam, assim como quantificar e discriminar o uso desta ferramenta diagnóstica no cotidiano das especialidades. Materiais e métodos: Profissionais cursando algum tipo de especialização tiveram que responder a um questionário de respostas certo/errado, que continha parâmetros sobre as indicações do uso da tomografia computadorizada na Odontologia, assim como perguntas que permitiram o levantamento de informações acerca desta ferramenta diagnóstica no tocante a influência do custo do procedimento, necessidade de treinamento específico para interpretação e necessidade de investimento por parte do profissional clínico. Resultados: Pudemos observar que a indicação da técnica não está totalmente esclarecida para muitos Cirurgiões-Dentistas. A porcentagem de desconhecimento foi significativa (27%), por se tratar de radiação ionizante, que pode causar riscos estocásticos e deletérios. Pudemos observar em nossos resultados que existe um embasamento geral da técnica, pois à medida que especialistas de uma certa área acertaram questões correspondentes a outras especialidades, notamos a ocorrência de equívocos de conceitos quando eram questionados sobre o protocolo de uso em sua própria área de conhecimento. Conclusão: A divulgação dos dados obtidos será de grande valia para o clínico geral, bem como para os especialistas, no intuito de reduzir a dose de exposição desnecessária quando da indicação da técnica. A necessidade de aprimorar o conhecimento será sempre necessária, para que não tenhamos apenas o conhecimento geral, mas o específico para a área de atuação de cada um.

Objective: To determine, among dental professionals, the degree of training and information regarding the use of CBCT, as well as to quantify and discriminate the use of this diagnostic tool in specialties daily basis. Materials and methods: Professionals attending specialization courses had to answer a right/wrong answers questionnaire containing parameters of indications for the use of computed tomography in dentistry. Beyond that, they had to answer questions that allowed the collection of information about this diagnostic tool regarding the influence of the cost of the procedure, the need for specific training in the interpretation and need for investment by the clinical professional. Results: We observed that the technique is not entirely clear for many dentists. The percentage of unawareness was significant (27%) considering it is about an ionizing radiation, which can cause deleterious and stochastic risks. We observed in our results that there is a general grounding of the technique, because on the one hand experts of a determined area showed a certain knowledge of other specialties, on the other hand we verified there were misunderstandings of concepts when questioned about the protocol used in their own area of knowledge. Conclusion: The release of the data obtained will be of great value to the general practitioner as well as to specialists in order to reduce the amount of unnecessary exposure in the indication of the technique. Improve knowledge will always be necessary so we will not only have general knowledge, but the specific one to the area of each dentistry professional.

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Objetivo: Avaliar a nanodureza (Nn) e o módulo de elasticidade (ME) da região de adesão quando utilizados diferentes sistemas adesivos e correlacionar com a resistência adesiva (RA) à dentina. Método: Foram medidos a nanodureza e o módulo de elasticidade da resina composta junto à área de união, da camada de adesivo (Ad), da camada híbrida (Ch), e da dentina adjacente utilizando testes de nanoendentação. Quarenta molares (n=10) foram preparados de modo a obterem-se superfícies planas em dentina, sobre as quais os sistemas adesivos foram aplicados (Adper Scotchbond Multiuso, Adper Single Bond 2, Adper SE Plus e Clearfil SE Bond). Sobre essas superfícies foi inserida a resina composta. Os dentes restaurados foram seccionados para obterem-se corpos-de-prova com área aderida de 1mm2. Um palito de cada dente foi selecionado para análise da nanodureza e do módulo de elasticidade da interface adesiva. Os demais tiveram a resistência de união testada através do teste de microtração. Resultados: O teste ANOVA detectou diferença estatística entre todos os grupos, exceto para a variável nanodureza da camada híbrida. O teste de correlação de Pearson detectou significância para o módulo de elasticidade. Conclusões: Pôde-se concluir que as propriedades mecânicas (resistência adesiva, módulo de elasticidade e nanodureza do sistema adesivo e da camada híbrida) variam dependendo do sistema adesivo. Quanto maior o módulo de elasticidade da camada híbrida de um sistema adesivo maior é sua resistência adesiva e menor o módulo de elasticidade da camada de adesivo. Pôde observar que não houve correlação entre nanodureza e a resistência adesiva.

To evaluate the nanohardness (Nn) and the modulus of elasticity (ME) in the region of adhesion when used different adhesive systems and correlate with the bond strength to dentin (RA). We measured the nanohardness and the modulus of elasticity of the resin composed with the area of bond of the adhesive layer (Ad), hybrid layer (Ch) and adjacent dentin using nanodentition tests. Forty molars (n = 10) were prepared in order to obtain flat dentin surfaces on which the adhesive systems were applied (Adper Scotchbond Multipurpose, Single Bond 2, Adper SE Plus and Clearfil SE Bond). On these surfaces was inserted a composite resin. The restored teeth were sectioned to obtain body-of-proof with adhered area of 1mm2. A stick of each teeth was selected for the nanohardness analysis and the modulus of elasticity of the adhesive interface. The others had the bond strength tested using the microtensile test. The ANOVA detected statistical difference between all groups, except for the variable nanohardness of the hybrid layer. The Pearson’s correlation test found significance for the modulus of elasticity. It was concluded that the mechanical properties (bond strength, the modulus of elasticity and nanohardness of the adhesive system and the hybrid layer) vary depending on the adhesive system. The higher the modulus of elasticity of the hybrid layer of an adhesive system a greater adhesive strength will be and lower the modulus of elasticity of the adhesive layer. It can be observed that there was no correlation between nanohardness and bond strength.

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Avaliar a resistência de união, pelo ensaio de tração, de sistemas adesivos autocondicionantes e baseados no condicionamento ácido total em diferentes superfícies dentinárias de molares decíduos e analisar a interface de união adesiva. Metodologia: Neste estudo in vitro, amostras de dentina de 35 a 65% de distância pulpar (dentina intermediária) foram obtidas do terço médio das faces vestibular e lingual/palatina de primeiros e segundos molares decíduos. As superfícies dentinárias foram polidas com lixas de carboneto de silício de granulação 400 e 600. Três sistemas adesivos (Prime & Bond NT, AdheSE e Clearfil SE Bond) foram empregados nas amostras dos primeiros e segundos molares (n=15); corpos de prova foram confeccionados em resina composta com uma área de adesão de 2 mm de diâmetro. Após 24 horas de armazenagem em água destilada a 37ºC, fez-se o ensaio de tração. Para a análise da interface de união adesiva entre sistema adesivo e dentina usando microscopia eletrônica, as amostras foram preparadas com os mesmos três sistemas adesivos (n=5). Resultados: Não foram observadas diferenças estatisticamente significantes nos valores de adesão entre primeiros e segundos molares (ANOVA; p>0,05). Os seguintes valores médios de adesão em MPa foram obtidos: 15,65±3,70 (Prime & Bond NT), 19,47±7,09 (AdheSE) e 17,14±5,35 (Clearfil SE Bond). Não foram observadas diferenças estatisticamente significantes entre os adesivos autocondicionantes. A formação de camada híbrida e tags foi observada em todos os grupos. Conclusões: Os sistemas adesivos contemporâneos apresentaram comportamentos similares em ambos os tipos de superfícies tubulares dentinárias dos molares decíduos. Estudos de seguimento são necessários para o acompanhamento do desempenho clínico desses materiais...

Aims: To evaluate the tensile bond strength of self-etching and total-etching adhesive systems to the different dentin surfaces of primary molars and to analyze the resin-dentin interface. Methodology: In this in vitro study, dentin samples 35 to 65% distant from the pulp (intermediate dentin) were obtained from buccal and lingual surfaces at the middle third of the crown of first and second primary molars. Dentin surfaces were prepared with 400 and 600-grit silicon carbide paper. Three adhesive systems (Prime & Bond NT, AdheSE and Clearfil SE Bond) were tested on the first and second primary molar surfaces (n=15); inverted truncated cones of resin composite with a 2.0 mm bonding diameter were built. After 24 hour storage in distilled water at 37°C, the specimens were submitted to the tensile bond strength test. To analyze the resin-dentin interface under scanning electron microscopy, samples were prepared with the same three adhesive systems (n=5). Results: No differences between first and second primary molar dentin substrates could be observed in mean bond strength values (ANOVA; p>0.05). The following mean bond strength values (MPa) were obtained: 15.65±3.70 (Prime & Bond NT), 19.47±7.09 (AdheSE) and 17.14 ±5.35 (Clearfil SE Bond). There were no statistically significant differences between the self-etching adhesive systems. The presence of hybrid a layer and tags were observed in all groups. Conclusions: Contemporary adhesive systems showed similar behaviors on both dentin tubular surfaces of primary molars. Follow-up studies of the clinical performance of these materials are needed...

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Objetivo: avaliar a dureza de uma resina composta fotoativada com dois métodos diferentes, contínuo e soft-start, por meio da variação da distância entre a ponta fotoativadora e a resina composta (7 mm e 0 mm). Materiais e métodos: Foram confeccionados 20 corpos-de-prova, nos quais a superfície irradiada e a oposta foram analisadas, totalizando 40 superfícies divididas em quatro grupos (n = 10): Grupo 1, método contínuo superfície irradiada; Grupo 2, método contínuo superfície oposta; Grupo 3, método soft-start superfície irradiada; Grupo 4, método soft-start superfície oposta. Os corpos-de-prova foram confeccionados com o auxílio de matrizes pretas de polipropileno, com 4 mm de diâmetro e 2 mm de espessura, utilizando a resina composta Z350 (3M ESPE) na cor AO3 e o fotoativador Elipar Freelight 2 (3M ESPE). Os corpos-de-prova foram submetidos ao teste de microdureza Vickers, no microdurômetro HMV- 2000 (Shimadzu). Foram realizados cinco entalhes por superfície, com carga de 50 gf por 45 segundos. Para a análise estatística, foram realizados os testes de ANOVA e Tukey. Resultados: Não foi encontrada diferença estatisticamente signifi cante entre os métodos avaliados nas superfícies irradiadas. Entretanto, nas superfícies opostas, houve diferença entre os protocolos, sendo que o soft-start obteve menores valores de dureza. Quando comparadas as diferentes profundidades, houve redução nos valores de dureza para ambos os métodos de fotoativação, de forma que a porcentagem de dureza máxima de 80% não foi atingida na superfície oposta à irradiada. Relevância: O cirurgião-dentista, em sua prátic clínica, deve atentar para o método de fotoativação de suas restaurações, visto que este pode prejudicar a qualidade da polimerização de resinas compostas, especialmente na profundidade de 2 mm em resinas opaca.

Objective: to evaluate the hardness of a composite resin polymerized with two different methods, continuous and soft-start, by varying the distance between the activator tip and the composite resin (7 mm and 0 mm). Materials and Methods: Twenty test specimens were fabricated, in which the irradiated and the opposite surfaces were analyzed, totaling 40 surfaces divided into 4 groups (n = 10): Group 1, continuous method + irradiated surface; Group 2, continuous method + opposite surface; Group 3, soft-start method + irradiated surface; Group 4, soft-start method + opposite surface. The test specimens were prepared using black polypropylene matrices, with a diameter of 4 mm and thickness of 2 mm, Z350 composite resin (3M ESPE), shade AO3, and the Elipar Freelight 2 curing unit (3M ESPE). The test specimens were subjected to nthe Vickers hardness test in an HMV-2000 microhardness tester (Shimadzu). Five indentations were made per surface with a load of 50 gf for 45 seconds. The ANOVA and Tukey tests were used for the statistical analysis. Results: No statistically signifi cant difference between the evaluated methods was found in the irradiated surfaces; however, in the opposite surfaces, there were differences between protocols, in that the soft-start protocol achieved the lowest hardness values. When comparing the different depths, there was a reduction in hardness values for both activation methods, so that the maximum hardness percentage of 80% was not achieved in the opposite surface. Relevance: The dentist should be knowledgeable of the photoactivation method applied to his/her restorations, since it may reduce the polymerization quality, especially in depths of 2 mm when using opaque resins.

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The aim of the present study was to investigate the in vitro effect of CO2 laser on the inhibition of root surface demineralization around composite resin restorations. For this purpose, 30 blocks obtained from human molar roots were divided into three groups: group 1 (negative control), cavity prepared with cylindrical diamond bur + acid etching + adhesive + composite resin restoration; group 2, cavity prepared with cylindrical diamond bur + CO2 laser (5.0 J/cm(2)) + acid etching + adhesive + composite resin; and group 3, cavity prepared with cylindrical diamond bur + CO2 laser (6.0 J/cm(2)) + acid etching + adhesive + composite resin. After this procedure, the blocks were submitted to thermal and pH cycling. Root surface demineralization around the restorations was measured by microhardness analysis. The hardness results of the longitudinally sectioned root surface were converted into percentage of mineral volume, which was used to calculate the mineral loss delta Z (ΔZ). The percentage of mineral volume, ΔZ, and the percentage of demineralization inhibition of the groups were statistically analyzed by using analysis of variance and Tukey-Kramer test. The percentage of mineral volume was higher in the irradiated groups up to 80 µm deep. The ΔZ was significantly lower in the irradiated groups than in the control group. The percentage of reduction in demineralization ranged from 19.73 to 29.21 in position 1 (50 µm), and from 24.76 to 26.73 in position 2 (100 µm), when using 6 and 5 J/cm(2), respectively. The CO2 laser was effective in inhibiting root demineralization around composite resin restorations.

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A descolagem acidental do bráquete é uma severa complicação no decorrer do tratamento ortodôntico, especialmente quando o tratamento é feito com bráquetes linguais. A força de adesão entre o bráquete e o dente é um importante requisito para o sucesso da Ortodontia Lingual na prática diária do consultório. O presente estudo analisou a influência do jateamento do óxido de alumínio na superfície lingual dos dentes antes do condicionamento do esmalte na colagem indireta do aparelho lingual. A força de cisalhamento foi medida 24 horas após a colagem dos bráquetes. Os dentes foram divididos em quatro grupos: G1 - 10 pré-molares com bráquetes da marca American Orthodontics com condicionamento de ácido ortofosfórico a 37%; G2 - 10 pré-molares com bráquetes da marca American Orthodontics com aplicação do jato de óxido de alumínio e ácido ortofosfórico a 37% no esmalte; G3 - 10 pré-molares com bráquetes da marca Ormco com condicionamento de ácido ortofosfórico a 37% e G4 - 10 pré-molares com bráquetes da marca Ormco com aplicação do jato de óxido de alumínio e ácido ortofosfórico a 37% no esmalte. Avaliou-se a resistência ao cisalhamento e observou-se que não ocorreu diferença estatisticamente significante entre os grupos quanto aos diferentes modos de preparo de esmalte. Com relação às marcas comerciais, os bráquetes da American Orthodontics apresentaram resistência à descolagem maior do que os bráquetes da marca Ormco. Concluindo, a resistência à descolagem dos bráquetes não foi aumentada com a aplicação prévia do jato de óxido de alumínio no esmalte hígido, nas duas marcas comerciais de bráquetes.

Accidental bracket debonding is a severe complication throughout orthodontic treatment, especially when using lingual brackets. The bond strength between the bracket and the tooth is an important requirement for the success of Lingual Orthodontics. This study has analyzed the influence of aluminum oxide blasting on the lingual surface of the teeth, before conditioning of the enamel, over indirect bonding of the lingual brace. Shear strength was measured 24 hours after brackets bonding. Teeth were divided into four groups: G1 - 10 premolar teeth with American Orthodontics brackets and 37% orthophosphoric acid conditioning; G2 - 10 premolar teeth with American Orthodontics brackets and application of aluminum oxide and 37% orthophosphoric acid blasting on the enamel; G3 - 10 premolar teeth with Ormco brackets and 37% orthophosphoric acid conditioning; G4 - 10 premolar teeth with Ormco brackets, application of aluminum oxide and 37% orthophosphoric acid blasting on the enamel. When evaluating the shear resistance through mechanical assay, it was not observed statistically significant difference between the groups regarding different enamel preparation modes. Concerning the different commercial brands, the American Orthodontics brackets showed higher debonding resistance than the Ormco brackets. It was concluded that, for both brands of brackets, the resistance to bracket debonding did not increase with the previous application of aluminum oxide blasting on the ename.

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O objetivo desse estudo foi avaliar a lisura de superfície de três resinas compostas por nanopartículas, após serem submetidas a três diferentes sistemas de acabamento e polimento. Foram obtidos 40 corpos de prova de cada resina (Filtek Z350 XT, Premise e Charisma Diamond) e distribuídos em quatro grupos experimentais (n=10): C (controle) - sem tratamento; SOF -Discos abrasivos Soflex; ENH - Pontas siliconadas Enhance e F/FF - Pontas diamantadas de granulação fina/extra-fina + disco de feltro e pasta diamantada. Após 24h da confecção e armazenamento, os sistemas de acabamento e polimento foram aplicados. A lisura superficial foi avaliada utilizando-se um rugosímetro, tendo sido realizadas cinco leituras em cada corpo de prova. A média dos valores de rugosidade de superfície [um] obtidos foi analisada através da ANOVA, dois fatores, seguido do teste de Tukey, com significância de 1%. Para todas as resinas testadas, houve diferença estatística entre os sistemas de acabamento e polimento testados (p<0,01). Para a resina Charisma, os valores de rugosidade foram: C - 0,10a; SOF - 0,24b; ENH - 0,23b; F/ FF - 0,32c. Para a Premisa: C-0,12a; SOF - 0,16ab; ENH - 0,22b; F/FF - 0,30<. Para a Filtek: C - 0,08'; SOF - 0,14ab; ENH - 0,20b<; F/FF - 0,26<. No grupo controle foram obtidos os melhores resultados de lisura de superfície para todas as resinas testadas. Em relação aos tratamentos, os grupos SOF e ENH promoveram as melhores lisuras de superfície, enquanto que o grupo F/FF resultou em superfícies com maiores rugosidades.

The aim of this study was to evaluate the smoothness surface of 3 composites by nanoparticles (Filtek Z350 XT, Premise e Charisma Diarnond], after being subjected to three different finishing and polishing systems. Were obtained 40 specimens of each resin selected and randomly divided into 4 experimental groups (n= 10): C (control) - no treatment; SOF - Abrasive discs Soflex; ENH - silicon tips Enhance; and F / FF - diamond tips fine/extra-fine granulation + felt disc and diamond paste. Twenty-four hours after the preparation and storage of the specimens in distilled water at 37°(, the finishing and polishing systems were applied. The smooth surface of the composites was evaluated using a rugosimeter, where five readings were taken on each specimen. The mean surface roughness (um) were analyzed by ANOVA, two factors, followed by Tukev's test, with significance of 1%. For ali resins tested, statistical difference was found between finishing and polishing systems tested (p<0,01). To the resin Charisma roughness values were: C - 0,10a; SOF - 0,24b; ENH - 0,23b; F/ FF - 0,32c. For the premise : C-0,12a; SOF - 0,16ab; ENH - 0,22b; F/FF - 0,30<. Para a Filtek: C - 0,08'; SOF - 0,14ab; ENH - 0,20b<; F/FF - 0,26<. The control group obtained better results of surface smoothness for ali composites tested. Regarding the treatments groups, SOF and ENH resulted on better smoothness surface, while the group FI FF resulted in surfaces with higher roughness.

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