Abstract The effectiveness of at-home dental bleaching treatments depends on the time that bleaching products are in contact with the teeth surface and, consequently, on the adequate use of associated custom acetate trays. Objective This randomized single-blinded trial aimed to analyze if the daily usage time of these products influences the patient’s compliance behavior when submitted to monitored at-home dental bleaching. Secondary outcomes were color change and tooth sensitivity. Methodology Sixty-six volunteers were randomly distributed into three groups (n=22): patients were instructed to use the trays for 2 (G2), 4 (G4), and 8 (G8) hours daily. The daily dental bleaching compliance behavior was measured using a microsensor inserted into the trays. Subjective and objective color evaluation assessments were adopted at baseline (T0), one (T1), two (T2), and three weeks (T3) after the beginning of the bleaching treatment, as well as two weeks after the treatment (T4). Tooth sensitivity was analyzed using the VAS scale, ranging from T1 to T4. Results G2 showed a greater degree of cooperation than G8 and cooperation was inversely proportional to the recommended usage time. Significantly higher color change was observed in the upper arch for G8 when compared to G2 in subjective analysis, from T1 to T4. There were no statistical differences between the groups in objective analysis. Conclusion Shorter recommended usage time of the bleaching product may improve the patient's compliance with at-home dental bleaching treatments. However, increased daily usage time may promote better subjective color change. Bleaching sensitivity was more significant in the first week for a longer time of use.

Resumo O objetivo deste estudo foi avaliar os efeitos das concentrações de ácido fluorídrico (AF) e do prévio tratamento térmico (PTT) na morfologia da superfície e resistência de união ao microcisalhamento (mRUM) de uma cerâmica vítrea de dissilicato de lítio (EMX) ao cimento resinoso. Cento e quatro espécimes de EMX foram aleatoriamente distribuídos em dois grupos (n=52) de acordo com a concentração do AF: 5% e 10%. Os espécimes foram novamente distribuídos de forma aleatória de acordo com o PTT (n=13): controle (sem PTT); AF previamente aquecido (70 °C); superfície do EMX previamente aquecida (85 °C); combinação entre AF e EMX aquecidos. O tempo de condicionamento foi fixado em 20 s. Todos os espécimes de EMX foram silanizados e receberam a aplicação de uma fina camada de um adesivo sem carga. Cinco cilindros de cimento resinoso foram confeccionados usando tubos Tygon como matrizes e então armazenados por 24 h a 37 °C. Uma amostra condicionada de cada grupo foi aleatoriamente selecionada e analisada em um microscópio eletrônico de varredura em emissão de campo (MEVEC). Os dados foram submetidos ao teste ANOVA de dois fatores e múltiplas comparações foram feitas pelo teste de Tukey (a=0.05). Para os grupos controle, AF 5% mostrou valor de mRUM estatisticamente menor do que AF 10% (p<0.05). PTT aumentou os valores de mRUM para o AF 5%, proporcionando resultados estatisticamente similares ao grupo AF 10% controle (p<0.05). MEVEC mostrou um aumento na remoção da matriz vítrea quando o PTT foi aplicado ao grupo AF 5%, no entanto esse efeito não foi visto no grupo AF 10%. O PTT tem o potencial de melhorar a resistência de união do AF 5% na cerâmica vítrea reforçada por disilicato de lítio.

Abstract The aim of this study was to evaluate the effects of hydrofluoric acid (HF) concentration and previous heat treatment (PHT) on the surface morphology and micro-shear bond strength (mSBS) of a lithium disilicate glass ceramic (EMX) to resin cement. One hundred four EMX specimens were randomly assigned to two groups (n=52) according to the HF concentration: 5% and 10%. A new random distribution was made according to the PHTs (n=13): control (no PHT); previously heated HF (70 °C); previously heated EMX surface (85 °C); the combination of heated HF + heated EMX surface. The etching time was set at 20 s. All EMX blocks were silanated and received a thin layer of an unfilled resin. Five resin cement cylinders were made on each EMX surface using Tygon tubes as matrices, and then stored for 24 h at 37 °C. One random etched EMX sample from each group was analyzed using field-emission scanning electron microscopy (FE-SEM). The data were subjected to two-way ANOVA and multiple comparisons were performed using the Tukey post hoc test (a=0.05). For the control groups, 5% HF showed statistically lower mSBS values when compared to 10% HF (p<0.05). PHT increased the mSBS values for 5% HF, yielding statistically similar results to non-PHT 10% HF (p<0.05). FE-SEM images showed increased glassy matrix removal when PHT was applied to HF 5%, but not to the same degree as for 10% HF. PHT has the potential to improve the bond strength of 5% HF concentration on lithium disilicate glass ceramic.

Resumo O objetivo deste estudo foi avaliar o efeito da ciclagem de pH erosiva com soluções que simulam a erosão dental, na dureza Martens (HMV) e módulo de elasticidade (Eit) da dentina restaurada com sistemas adesivos contendo fluoretos. Vinte e sete blocos de dentina foram restaurados com três sistemas adesivos: sistema adesivo de condicionamento total Adper Single Bond 2 e sistemas adesivos autocondicionantes contendo fluoreto One Up Bond F e Clearfil SE Protect. As restaurações foram realizadas com resina Filtek Z250. Os valores de HMV e Eit nas distâncias de 10, 30, 50 e 70µm da interface foram avaliadas em ultramicrodurômetro dinâmico antes e após a imersão em água deionizada, ácido cítrico e ácido clorídrico (n=9). Dados foram submetidos à ANOVA para medidas repetidas e Fisher PLSD (α=0,05). Após a ciclagem erosiva, os valores de HMV da dentina diminuíram em todos os grupos. Para a dentina restaurada com Adper Single Bond 2, os menores valores foram encontrados próximo a camada híbrida enquanto que, para os sistemas adesivos One Up Bond F e Clearfil SE Protect, os valores permaneceram inalterados em todas as distâncias. Para a dentina restaurada com os materiais que liberam fluoretos, uma redução nos valores de Eit foi encontrada, mas após 30µm essa diferença não foi mais significante. As substâncias ácidas foram capazes de alterar a HMV e o Eit da dentina subjacente. Para os adesivos que liberam fluoretos, quanto maior a distância da interface adesiva, menor os valores de Eit. O fluoreto presente no One Up Bond F e Clearfil SE Protect foi capaz de proteger a dentina subjacente próxima aos materiais. Dessa maneira, a presença do flúor em sistemas adesivos pode ter algum efeito positivo em estágios iniciais de lesões erosivas.

Abstract The aim of the study was to evaluate the effect of erosive pH cycling with solutions that simulate dental erosion on Martens hardness (HMV) and elastic modulus (Eit) of dentin restored with fluoride-releasing adhesive systems. Twenty-seven bovine dentin slabs were restored with three adhesive systems: Adper Single Bond 2 total-etch adhesive system, One Up Bond F and Clearfil SE Protect fluoride-containing self-etching adhesive systems. The restorations were made with Filtek Z250. The HMV and Eit values at distances of 10, 30, 50 and 70 µm from the interface were evaluated using a dynamic ultra microhardness tester before and after immersion in deionized water, citric acid and hydrochloric acid (n=9). Data were submitted to repeated-measures ANOVA and Fisher's PLSD tests (=0.05). After erosive cycling, HMV values of dentin decreased in all groups. For dentin restored with Adper Single Bond 2, the lowest values were found closer to the hybrid layer, while for One Up Bond F and Clearfil SE Protect, the values remained unaltered at all distances. For dentin restored with fluoride-releasing adhesive systems, a decrease in Eit was found, but after 30 µm this difference was not significant. The acid substances were able to alter HMV and Eit of the underlying dentin. For fluoride-releasing adhesives, the greater the distance from bonded interface, the lower the Eit values. The fluoride in One Up Bond F and Clearfil SE Protect was able to protect the underlying dentin closer to the materials. In this way, the fluoride from adhesive systems could have some positive effect in the early stages of erosive lesions.

AIM: This study evaluated saliva effects on enamel morphology surface after microabrasion technique. METHODS: Enamel blocks (16 mm2) obtained from bovine incisors were divided into 9 groups as follows: one control group (no treatment), four groups with microabrasion treatment using 35% phosphoric acid and pumice (H3PO4+Pum) and other four groups treated with 6.6% hydrochloric acid and silica (HCl+Sil). One group of each treatment was submitted to 4 frames of saliva exposure: without exposure, 1-h exposure, 24-h exposure, and 7-days exposure on in situ regimen. Nineteen volunteers (n=19), considered as statistical blocks, used an intraoral appliance containing the specimens, for 7 days. Enamel roughness (Ra) was tested before and after treatment, and after saliva exposure. Confocal laser scanning microscopy (CLSM) was used to evaluate qualitatively the enamel morphology. RESULTS: All groups exhibited increased Ra after microabrasion. With regards to saliva exposure, the treatment with HCl+Sil presented more susceptibility to the saliva action, but no period of time was efficient in re-establishing this characteristic compared with the control group. CLSM analysis showed reduction of the micro-abrasive damages during the experimental times. CONCLUSIONS: Seven days of saliva exposure were not sufficient for the treated enamel to reach its normal characteristics compared with the control group.

Superficial irregularities and certain intrinsic stains on the dental enamel surfaces can be resolved by enamel microabrasion, however, treatment for such defects need to be confined to the outermost regions of the enamel surface. Dental bleaching and resin-based composite repair are also often useful for certain situations for tooth color corrections. This article presented and discussed the indications and limitations of enamel microabrasion treatment. Three case reports treated by enamel microabrasion were also presented after 11, 20 and 23 years of follow-ups.

O objetivo dessa pesquisa foi mensurar a espessura da camada hibrida de adesao (CH), o comprimento dos prolongamentos resinosos (Tags) e a resistencia de uniao (RU) em um mesmo especime e analisar a correlacao entre esses fatores, usando o adesivo autocondicionante Adper Prompt L Pop em dentina higida. Dez molares humanos foram utilizados e apos a realizacao dos procedimentos restauradores, de acordo com os fabricantes, cada especime foi cortado ao meio no sentido mesio/distal. Em uma hemi-seccao dental os especimes foram descalcificados para analise e mensuracao dos tags e da camada hibrida de adesao em microscopia optica comum (AXIOPHOT, 400X). Na outra hemi-seccao, foi realizado o teste de microtracao em uma velocidade de 0,5 mm/min ate sua ruptura. A superficie fraturada foi mensurada e classificada de acordo com o tipo de fratura observada em microscopia eletronica de varredura. Os valores obtidos para os fatores em analise, correspondentes a cada especime foram submetidos a um teste de correlacao. As medias correspondentes a CH, Tags e RU foram 3,36μm, 12,97 μm 14,10 MPa, respectivamente. Nao foi observado correlacao entre a CH e RU (R2= 0,011, p>0,05) e entre os Tags e RU (R2= 0,038). Diante dos resultados, observamos nao haver correlacao entre a camada hibrida e a resistencia a tracao, assim como entre os tags e a resistencia a tracao do sistema adesivo autocondicionante empregado.

The objective of this study was to measure the thickness of the hybrid layer (HLT), length of resin tags (RTL) and bond strength (BS) in the same teeth, using a self-etching adhesive system Adper Prompt L Pop to intact dentin and to analyze the correlation between HLT and RTL and their BS. Ten human molars were used for the restorative procedures and each restored tooth was sectioned in mesio-distal direction. One section was submitted to light microscopy analysis of HLT and RTL (400×). Another section was prepared and submitted to the microtensile bond test (0.5 mm/min). The fractured surfaces were analyzed using scanning electron microscopy to determine the failure pattern. Correlation between HLT and RTL with the BS data was analyzed by linear regression. The mean values of HLT, RTL and BS were 3.36 μm, 12.97 μm and 14.10 MPa, respectively. No significant relationship between BS and HLT (R2= 0.011, p>0.05) and between BS and RTL (R2= 0.038) was observed. The results suggested that there was no significant correlation between the HLT and RTL with the BS of the self-etching adhesive to dentin.

The presence of porosities at the dentin/adhesive interface has been observed with the use of new generation dentin bonding systems. These porosities tend to contradict the concept that etching and hybridization processes occur equally and simultaneously. Therefore, the aim of this study was to evaluate the micromechanical behavior of the hybrid layer (HL) with voids based on a self-etching adhesive system using 3-D finite element (FE) analysis. MATERIAL AND METHODS: Three FE models (Mr) were built: Mr, dentin specimen (41x41x82 μm) with a regular and perfect (i.e. pore-free) HL based on a self-etching adhesive system, restored with composite resin; Mp, similar to M, but containing 25% (v/v) voids in the HL; Mpp, similar to Mr, but containing 50% (v/v) voids in the HL. A tensile load (0.03N) was applied on top of the composite resin. The stress field was obtained by using Ansys Workbench 10.0. The nodes of the base of the specimen were constrained in the x, y and z axes. The maximum principal stress (σmax) was obtained for all structures at the dentin/adhesive interface. RESULTS: The Mpp showed the highest peak of σmax in the HL (32.2 MPa), followed by Mp (30 MPa) and Mr (28.4 MPa). The stress concentration in the peritubular dentin was high in all models (120 MPa). All other structures positioned far from voids showed similar increase of stress. CONCLUSION: Voids incorporated into the HL raised the σmax in this region by 13.5%. This behavior might be responsible for lower bond strengths of self-etching and single-bottle adhesives, as reported in the literature.

The bond strength of composite resins (CRs) to dentin is influenced by the interfacial microstructure of the hybrid layer (HL) and the resin tags (TAG). The contemporary self-etching primer adhesive systems overcame the inconvenient of the etch-and-rinse protocol. Studies, however, have demonstrated that HL thickness and TAG length vary according to the wetting time and additional use of acid-etching prior to self-etching primers. This study investigated the localized stress distribution in the HL and the dentin/adhesive interface. Two HL thicknesses (3 or 6 µm), two TAG lengths (13 or 17 µm) and two loading conditions (perpendicular and oblique-25º) were investigated by the finite element (FE) analysis. Five two-dimensional FE models (M) of a dentin specimen restored with CR (38 x 64 µm) were constructed: M1 - no HL and no TAG; M2 - 3 µm of HL and 13 µm of TAG; M3 - 3 µm of HL and 17 µm of TAG; M4 - 6 µm of HL and 13 µm of TAG; and M5 - 6 µm of HL and 17 µm of TAG. Two distributed loadings (L) (20N) were applied on CR surface: L1 - perpendicular, and L2 - oblique (25º). Fixed interfacial conditions were assigned on the border of the dentin specimen. Ansys 10.0 (Ansys®, Houston, PA, USA) software was used to calculate the stress fields. The peak of von Mises (sigmavM) and maximum principal stress (sigmamax) was higher in L2 than in L1. Microstructures (HL and TAG) had no effect on local stresses for L1. Decreasing HL decreased sigmavM and sigmamax in all structures for L2, but the TAG length had influence only on the peributular dentin. The thickness of HL had more influence on the sigmavM and sigmamax than TAG length. The peritubular dentin and its adjacent structures showed the highest sigmavM and sigmamax, mainly in the oblique loading.

Avaliação fotográfica para observar a presença ou a ausência de bolhas nos selantes de fóssula e fissuras Concise e Prisma Shield aos 7 dias, 18 meses, 36 meses e 11 anos, após a realização dos selamentos. METODOLOGIA: Foi aplicado na superfície oclusal, em todos os períodos de análise, uma solução corante a base de hematoxilina, que possibilitou a verificação e a avaliação dos materiais seladores presentes nesta superfície. Todas as superfícies oclusais foram fotografadas e as fotografias, correspondentes a cada período em análise, foram submetidas à avaliação fotográfica. RESULTADOS: Verificou-se diferença estatisticamente significativa somente aos 18 meses de análise, com o selante Prisma Shield apresentando um número significativamente maior de bolhas superficiais, que o selante Concise; enquanto que os demais grupos apresentaram-se estatisticamente semelhantes entre si, em todos os outros períodos de análise. Por outro lado, quando os selantes foram analisados isoladamente, nos períodos subseqüentes, não foi observada a presença de diferença estatisticamente significativa. CONCLUSÃO: De acordo com os resultados observados, pudemos verificar que os materiais seladores apresentaram o aparecimento e o desaparecimento de bolhas, fato que não interferiu na finalidade clínica do selamento realizado.

The purpose of this study was to employ photographic evaluation to observe the presence or absence of bubbles in pit and fissure sealants Concise and Prisma Shield, at 7 days, 18 months, 36 months and 11 years after accomplishment of treatment. METHODS: A hematoxylin-based staining solution was applied to the occlusal surface at the study periods, which allowed assessment of the sealing material on the surface. All occlusal surfaces were photographed and the photographs corresponding to each period were subjected to photographic evaluation. RESULTS: There was statistically significant difference only at 18 months, with a significantly higher number of specimens with bubbles for the Prisma Shield sealant compared to the Concise, whereas the groups were similar at all other study periods. On the other hand, separate analysis of subsequent periods of the sealants did not reveal any significant difference. CONCLUSIONS: According to the results of the present longitudinal investigation, it may be concluded that the sealing materials showed that bubbles came into and went out with time. However, this fact did not interfere with its clinical purpose, provided the remaining material covers the expected region of pits and fissures.

INTRODUCTION: A evolução dos aparelhos fotopolimerizadores pode ser notada nos diferentes sistemas introduzidos recentemente no mercado. A tecnologia apresentada pelos aparelhos LED promete maior tempo de vida útil, não gerar aquecimento e produzir luz específica para a ativação da canforoquinona. No entanto, ainda são necessários estudos complementares para se conhecer a real efetividade destes aparelhos na polimerização dos materiais. PROPOSTA: Neste trabalho foi verificada a microdureza de 4 cores (B-0,5, B-1, B-2 e B-3) da resina composta Filtek Z-250 (3M ESPE) quando polimerizadas com 4 fontes de luz, sendo uma halógena (Ultralux - Dabi Atlante) e três LED (Ultraled - Dabi Atlante, Ultrablue - DMC e Elipar Freelight - 3M ESPE). MÉTODOS: Os 192 corpos-de-prova foram distribuídos em 16 grupos e os materiais foram inseridos em único incremento em matrizes cilíndricas de 4mm X 4mm, sendo polimerizados pelo tempo preconizado pelo fabricante. Em seguida, foram submetidos ao teste de microdureza na superfície superior e inferior dos cilindros. RESULTADOS: Os valores de dureza obtidos foram submetidos à análise de variância e ao teste de Tukey ao nível de 5%. Foi observado que a dureza dos corpos-de-prova variou conforme a cor do material e aparelhos utilizados. O aparelho LED que emite maior intensidade luminosa proporcionou a obtenção dos maiores valores de dureza, com o croma B-0,5 possibilitando a melhor polimerização. Por outro lado aparelhos com baixa intensidade luminosa foram os menos efetivos. Também foi observado que a região do fundo dos corpos-de-prova foi mais sensível à mudança das cores. CONCLUSÕES: A intensidade de luz dos fotopolimerizadores LED é fundamental para seu bom funcionamento, principalmente quando empregadas resinas com croma mais acentuado.

INTRODUCTION: The evolution of light curing units can be noticed by the different systems recently introduced. The technology of LED units promises longer lifetime, without heating and with production of specific light for activation of camphorquinone. However, further studies are still required to check the real curing effectiveness of these units. PURPOSE: This study evaluated the microhardness of 4 shades (B-0.5, B-1, B-2 and B-3) of composite resin Filtek Z-250 (3M ESPE) after light curing with 4 light sources, being one halogen (Ultralux - Dabi Atlante) and three LED (Ultraled - Dabi Atlante, Ultrablue - DMC and Elipar Freelight - 3M ESPE). METHODS: 192 specimens were distributed into 16 groups, and materials were inserted in a single increment in cylindrical templates measuring 4mm x 4mm and light cured as recommended by the manufacturer. Then, they were submitted to microhardness test on the top and bottom aspects of the cylinders. RESULTS: The hardness values achieved were submitted to analysis of variance and to Tukey test at 5% confidence level. It was observed that microhardness of specimens varied according to the shade of the material and light sources employed. The LED appliance emitting greater light intensity provided the highest hardness values with shade B-0.5, allowing the best curing. On the other hand, appliances with low light intensity were the least effective. It was also observed that the bottom of specimens was more sensitive to changes in shade. CONCLUSION: Light intensity of LED light curing units is fundamental for their good functioning, especially when applied in resins with darker shades.