Analysis of color stability and degree of conversion of different types of resin composites

Abstract Resin composites containing surface pre-reacted glass (S-PRG) have been introduced to reduce demineralization and improve remineralization of the tooth structure. However, water diffusion within the material is necessary for its action, which can impair its overall physicomechanical properties over time, including color stability. This study aimed to evaluate the color stability and related degree of conversion (DC) of four resin composites. Discs (6 x 4 mm, n = 5/group) of microhybrid (MH), nanofilled (NF), nanohybrid (NH), and S-PRG-based nanohybrid (S-PRG-NH) composites with two opacities (A2/A2E and A2O/A2D) were prepared. Color (CIELab and CIEDE2000) was evaluated with a spectrophotometer after aging in grape juice (2 x 10 min/10mL/7days). The DC was analyzed by using Fourier transform infrared spectroscopy before and after light-curing. Data were statistically analyzed by using two-way analysis of variance and post-hoc least significant difference tests (p<0.05). In the color stability analysis, the interaction between filler type and opacity was significant (CIELab, p = 0.0015; CIEDE2000, p = 0.0026). NH presented the highest color stability, which did not differ from that of MH. The greatest color alteration was observed for S-PRG-NH. S-PRG fillers also influenced DC (p < 0.05). The nanohybrid resin composite presented favorable overall performance, which is likely related to its more stable organic content. Notwithstanding the benefits of using S-PRG-based nanohybrid resins, mostly in aesthetic procedures, professionals should consider the susceptibility of such resins to color alteration, probably due to the water-based bioactive mechanism of action.

Evaluation of contact angle and mechanical properties of resin monomers filled with graphene oxide nanofibers

Abstract This in vitro study synthesized hybrid nanofibers embedded in graphene oxide (GO) and incorporated them into experimental resin composite monomers to evaluate their physical-mechanical properties. Inorganic-organic hybrid nanofibers were produced with precursor solutions of 1% wt. GO-filled Poly (d,l-lactide, PLA) fibers and scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) characterized the morphology and chemical composition of the spun fibers. Resin composite monomers were developed and a total of 5% nanofibers were incorporated into the experimental materials. Three groups were developed: G1 (control resin monomers), G2 (resin monomers/PLA nanofibers), and G3 (resin monomers/inorganic-organic hybrid nanofibers). Contact angle (n=3), flexural strength (n=22), elastic modulus (n=22), and Knoop hardness (n=6) were evaluated. The mean of the three indentations was obtained for each sample. The normality of data was assessed by QQ Plot with simulated envelopes and analyzed by Welch's method (p<0.05). Overall, SEM images showed the regular shape of nanofibers but were non-aligned. Compositional analysis from EDS (n=6) revealed the presence of carbon and oxygen (present in GO composition) and Si from the functionalization process. The results of contact angle (°) and hardness (Kg/mm2) for each group were as follow, respectively: G1 (59.65±2.90; 37.48±1.86a), G2 (67.99±3.93; 50.56±1.03b) and G3 (62.52±7.40; 67.83±1.01c). The group G3 showed the highest Knoop hardness values (67.83 kg/mm2), and the flexural strength of all groups was adversely affected. The experimental resin composite composed of hybrid nanofibers with GO presented increased hardness values and hydrophilic behavior.

Resumo Este estudo in vitro sintetizou nanofibras híbridas embebidas em óxido de grafeno (GO), incorporando-as à uma resina composta experimental de monômeros para avaliar suas propriedades físico-mecânicas. Nanofibras híbridas inorgânica-orgânicas foram produzidas com soluções precursoras de fibras poli (d, l-lactídeo, PLA) preenchidas com GO a 1% em peso e microscopia eletrônica de varredura (MEV) e espectroscopia de raio-X de energia dispersiva (EDS) caracterizaram a morfologia e composição química das fibras. Monômeros de resina composta foram desenvolvidos e um total de 5% de nanofibras foi incorporado aos materiais experimentais. Três grupos foram desenvolvidos: G1 (monômeros de resina controle), G2 (monômeros de resina/ nanofibras de PLA) e G3 (monômeros de resina/nanofibras híbridas inorgânico-orgânicas). Ângulo de contato (n=3), resistência à flexão (n=22), módulo de elasticidade (n=22) e dureza Knoop (n=6) foram avaliados. A média das três endentações foi obtida para cada amostra. A normalidade dos dados foi avaliada pelo QQ Plot com envelopes simulados e analisada pelo método de Welch (p<0,05). No geral, as imagens de MEV mostraram forma regular de nanofibras, mas não alinhadas. A análise composicional de EDS (n=6) revelou a presença de carbono e oxigênio (presentes na composição do GO) e Si resultante do processo de funcionalização. Os resultados do ângulo de contato (°) e dureza (Kg/mm2) para cada grupo foram os seguintes, respectivamente: G1 (59,65±2,90; 37,48±1,86a), G2 (67,99±3,93; 50,56±1,03b) e G3 (62,52±7,40; 67,83±1,01c). G3 apresentou os maiores valores de dureza Knoop (67,83 kg/mm2), e a resistência à flexão de todos os grupos foi prejudicada. A resina composta experimental composta por nanofibras híbridas com GO apresentou maiores valores de dureza e comportamento hidrofílico.

Multidisciplinary approach for anatomical correction and diastema closure with laminates veneers: a clinical report / Abordagem multidisciplinar para correção anatômica e fechamento de diastemas com facetas laminadas: relato de caso clínico

Objective: multidisciplinary treatment has become increasingly common in dental offices and this treatment strategy is based on the achievement of a healthy, harmonious, and pleasant smile. In addition, the development of new ceramic systems and the possibility of making indirect restorations with a low thickness, such as laminates veneers, allowed combining highly satisfactory aesthetic properties, preserving the dental structure through minimally Invasive technique. Case report: this paper describes a multidisciplinary approach involving periodontics and restorative dentistry for the successful, functional, and aesthetic treatment in an adult patient. The digital smile design was performed as a guide to plan the clinical case considering factors such as tooth inclination and position, golden proportion, tooth size and shape. Discussion: based on these concepts, the present work reports, through a clinical case, the restoration of aesthetics and function with ceramic laminates veneers in lithium disilicate, in the case of anatomical correction and diastema closure. Conclusion: overall, the multidisciplinary treatment plan demonstrated to have greater advantages both for the aesthetics and function of the patient, as well as for the work team. During the 24-month follow-up, this case presented great functional and aesthetics results. (AU)

Introdução: o tratamento multidisciplinar tornou-se cada vez mais comum nos consultórios odontológicos, sendo uma estratégia baseada no tratamento da obtenção de um sorriso saudável, harmonioso e agradável. Além disso, o desenvolvimento de novos sistemas cerâmicos e a possibilidade de fazer restaurações indiretas com baixa espessura, como facetas laminadas, permitiram combinar propriedades estéticas altamente satisfatórias, preservando a estrutura dentária com o mínimo desgaste. Caso clínico: este artigo descreve uma abordagem multidisciplinar envolvendo Periodontia e Odontologia restauradora para um tratamento funcional e estético em um paciente adulto. O desenho digital do sorriso foi realizado como um guia para planejar o caso clínico, considerando fatores como inclinação e posição do dente, proporção áurea, tamanho e formato do dente. Discussão: com base nesses conceitos, o presente trabalho relata, através de um caso clínico, a restauração estética e funcional com laminados cerâmicos em dissilicato de lítio para correção anatômica e fechamento de diastemas. Conclusão: em geral, o plano de tratamento multidisciplinar demonstrou ter maiores vantagens tanto para a estética e função do paciente, quanto para a equipe de trabalho. Durante os 24 meses de acompanhamento, esse caso apresentou ótimos resultados funcionais e estéticos. (AU)

Influence of modulated photo-activation on shrinkage stress and degree of conversion of bulk-fill composites

Abstract This study aimed to evaluate the polymerization properties of bulk-fill materials (low and high-viscosity) by using high-intensity continuous light and intermittent photo-activation in terms of polymerization shrinkage stress and degree of conversion (DC). The following Bulk-fill and Conventional nanofilled resin composites were evaluated: Filtek Z350XT Flow (3M/ESPE), SureFil SDR Flow (Dentsply), Filtek Bulk Fill Flow (3M/ESPE), Filtek Z350XT (3M/ESPE) and Filtek Bulk Fill Posterior (3M/ESPE). A LED device (DB 685, Dabi Atlante) was used for both protocols: continuous uniform and intermittent photo-activation (light-on and light-off cycles) with identical radiant exposure (14 J/cm2). The polymerization shrinkage stress (n=6) was evaluated by inserting a single increment of 12 mm3 between two stainless steel plates (6×2 mm) adapted to a Universal Testing Machine (UTM), at different times. Measurements were recorded after photo-activation. The degree of conversion was evaluated by Fourier transformed infrared spectroscope (FTIR) with an attenuated total reflectance (ATR) accessory (n=5). Data were analyzed by three-way ANOVA and Tukey's HSD (α=0.05) tests. Bulk Fill Posterior presented higher shrinkage stress values when photo-activated with the intermittent technique (p<0.05). The intermittent photo-activation increased the degree of conversion for the low-viscosity bulk-fills (p<0.05). Therefore, the use of modulated photo-activation (intermittent) must be indicated with caution since its use can influence the shrinkage stress and degree of conversion of composites, which varies according to the resin formulations.

Resumo O presente estudo teve como objetivo avaliar as propriedades de polimerização de materiais bulk-fill (baixa e alta viscosidade) utilizando luz contínua de alta intensidade e fotoativação intermitente em relação ao estresse de contração de polimerização e grau de conversão (DC). As seguintes resinas compostas Bulk-fill e nanohíbridas convencionais foram avaliadas: Filtek Z350XT Flow (3M/ESPE), SureFil SDR Flow (Dentsply), Filtek Bulk Fill Flow (3M/ESPE), Filtek Z350XT (3M/ESPE) e Filtek Bulk Fill Posterior (3M/ESPE). Um dispositivo de LED (DB 685, Dabi Atlante) foi utilizado nos dois protocolos: fotoativação contínua e intermitente contínua (ciclos de liga e desliga) com exposição idêntica (14 J/cm2). A tensão de contração de polimerização (n=6) foi avaliada através da inserção de um incremento único de 12 mm3 entre duas placas de aço inoxidável (6×2 mm) adaptadas a uma Máquina de Ensaio Universal (UTM), em tempos diferentes. As medições foram registradas após a fotoativação. O grau de conversão foi avaliado por FTIR-ATR (n=5). Os dados foram analisados ​​pelos testes ANOVA a três fatores e teste de Tukey (α=0,05). A resina Bulk Fill Posterior apresentou maiores valores de tensão de contração quando fotoativadas com a técnica intermitente (p<0,05). A fotoativação intermitente aumentou o grau de conversão nas resinas bulk-fill de baixa viscosidade (p<0,05). Portanto, o uso de fotoativação modulada (intermitente) deve ser indicado com cautela, uma vez que seu uso pode influenciar a tensão de contração e o grau de conversão dos compósitos, o que varia de acordo com as formulações da resina.

Efeitos do clareamento dental em consultório para dentes polpados: uma revisão da literatura / Efeitos do clareamento dental em consultório para dentes polpados: uma revisão da literatura

Introdução: A busca por um padrão de dentes mais brancos tem estimulado o consumo de agentes clareadores e, apesar de ser um tratamento estético conservador, possíveis danos à estrutura oral podem ocorrer com o uso excessivo desses produtos. Objetivo: Discorrer sobre as principais implicações do clareamento dental em consultó rio realizado em dentes vitais, ressaltando os efeitos locais causados tanto nos tecidos moles, quanto nos duros. Metodologia: Trata-se de uma revisão de literatura, realizada nas bases de dados online: Pubmed, Lilacs e Scielo, incluindo artigos originais e de revisão. Utilizando os seguintes descritores: "Esmalte Dentário", "Clareamento Dental", "Clareadores" e "Sensibilidade da dentina". Conclusão: Observou-se que dentre os efeitos adversos, a sensibilidade dentária durante e após o clareamento de dentes vitais ocorre mais frequentemente, seguido da irritação gengival e das alterações da superfície do esmalte.

Introduction: the search for whiter teeth pattern has encouraged the consumption of bleaching agents and, despite being a conservative aesthetic treatment, possible damages to the oral structure can occur with excessive use of bleaching products. Objective: to describe the main implications of the vital tooth bleaching in-office, emphasizing the local effects in the soft and hard tissues. Methods: this is a literature review that used electronic databases: PubMED/ Medline, Lilacs and Scielo, including original and review articles. The following descriptors were used: "Dental Enamel", "Tooth Bleaching", "Bleaching Agents" and "Dentin Sensitivity". Conclusion: It was observed that among the adverse effects tooth sensitivity during and after vital tooth bleaching occur more often, followed the gingival irritation and alteration of the enamel surface.

Assessment of a conservative approach for restoration of extensively destroyed posterior teeth

Abstract Extensive restorations in posterior teeth always bring doubts to the clinicians regarding the best protocol, mainly when structures of reinforcement were lost. Objective This study aimed to evaluate the effect of beveling on the fracture resistance and pattern of class II (MOD) restored teeth. Methodology Ninety human premolars were randomly assigned into 9 groups: CTR (control/sound); NC (cavity preparation, non-restored); RU (restored, unbeveled); RTB (restored, entire angle beveling); RPB (restored, partial/occlusal beveling); EC (endodontic access/EA, non-restored); EU (EA, unbeveled); ETB (EA, entire angle beveling); EPB (EA, partial/occlusal beveling). Teeth were restored with Esthet X resin composite and stored in distilled water for 24 h before the inclusion in PVC cylinders. The axial loading tests were performed with 500 kgF at 0.5 mm/min crosshead speed until fracture of the specimens. Fracture resistance and pattern were accessed and data were analyzed using one-way ANOVA and Tukey's HSD test (α=0.05). Results Mean (±SD) failure loads ranged from 136.56 (11.62) to 174.04 (43.5) kgF in the groups tested without endodontic access. For endodontically accessed teeth, fracture resistance ranged from 95.54 (13.05) to 126.51 (19.88) kgF. Beveling of the cavosurface angle promoted the highest fracture resistance values (p<0.05) and prevented catastrophic fractures. Conclusions Cavosurface angle beveling is capable of improving fracture resistance and pattern for both endodonticaly accessed and non-accessed teeth.

Effect of a resin-modified glass-ionomer with calcium on enamel demineralization inhibition: an in vitro study

Abstract We assessed the effect of a new coating material based on resin-modified glass-ionomer with calcium (Ca) in inhibiting the demineralization of underlying and adjacent areas surrounding caries-like lesions in enamel. The measures used were surface hardness (SH) and cross-sectional hardness (CSH). Thirty-six bovine enamel specimens (3 × 6 × 2 mm) were randomly allocated into three groups (n = 12): No treatment (NT); resin-modified glass-ionomer with Ca (Clinpro XT Varnish, 3M ESPE) (CL), and fluoride varnish (Duraphat, Colgate) (DU). The specimens were subjected to alternated immersions in demineralizing (6 h) and remineralizing solutions (18 h) for 7 days. SH measurements were conducted at standard distances of 150, 300, and 450 µm from the treatment area. CSH evaluated the mean hardness profile over the depth of the enamel surface and at standard distances from the materials. The energy-dispersive X-ray spectroscopy analysis was conducted to evaluate the demineralization bands created on the sublayer by % of calcium (Ca), phosphorus (P), and fluoride (F). Ca/P weight ratio was also calculated. Based on SH and CSH measurements, there was no difference between groups at the distances 150 µm (p = 0.882), 300 µm (p = 0.995), and 450 µm (p = 0.998). Up to 50 µm depth (at 150 µm from the treatment area), CL showed better performance than DU ( p< 0.05). NT presented higher loss of Ca and P than CL and DU (p < 0.05). There was no significant difference in the % of F ion among the three groups. The new coating material was similar to F varnish in attenuating enamel demineralization.

Effect of sports drinks on the surface properties of composite resins after prolonged exposure - in vitro study

Aim: Using dietary supplements may affect the properties of composite resins due to their acidic pH. The present in vitro study aimed to assess the surface roughness and color stability of two composite resins - nanohybrid (Empress Direct) and nanoparticulate (Filtek Z350) - after prolonged exposure to dietary supplements. Methods: We produced 30 specimens from each composite (8x2-mm discs) and divided them into six groups (n=10). After the initial measurement of the surface properties (roughness and color), we exposed the specimens to a degradation process in Maltodextrin and Whey Protein for 22.5 and 7.5 days, respectively, using deionized water as the control solution. At the end of 22.5 days, we reassessed the specimens. After verifying data normality with the Kolmogorov-Smirnov test, we performed ANOVA followed by Tukey's test at 5%. Results: We found significant differences for materials immersed in the Whey Protein solution (p<0.05). The roughness of Empress Direct was higher (0.45+0.07) than Filtek Z350 (0.22+0.05). The composites tested also showed color change (ΔE>3.3) after the immersion period (p<0.001). In Maltodextrin, the Empress Direct group presented (4.52+1.23) and Filtek Z350 (4.04+0.66), while after immersion in Whey Protein, they showed (5.34+1.68) and (4.26+1.02), respectively. Conclusion: Sports drinks changed the surface roughness and color stability of the composite resins studied. The Filtek Z350 group showed lower color variation than the Empress Direct composite in both solutions evaluated

Understanding the interaction of resin composite with light for predictable aesthetic results in anterior teeth: A case report / Compreensão da interação das resinas compostas com a luz para resultados estéticos previsíveis em dentes anteriores: Relato de caso

This case report illustrates a conservative technique for reintervention on anterior composite restorations in a young patient with composite veneers. The treatment incorporated the use of photos and digital planning to establish a harmonious smile design. In order to conserve the dental tissues, existing resin composites restorations in maxillary anterior teeth were carefully removed to minimize enamel reduction, followed by a study of color and shade of teeth considering factors such as hue, chroma, luminosity, opacity, translucency and light effects. Eight direct veneers were built up with resin composite taking the optical properties of the material into account and their influence on the thickness of the layers that create specific light effects when superimposed on each other. To obtain excellent results with a predictable working protocol, nanohybrid composite systems facilitate good aesthetics, avoiding more invasive treatment in an economic manner.(AU)

O presente relato de caso ilustra uma técnica conservadora para a re-intervenção em restaurações diretas de resina composta em pacientes jovens. O tratamento consistiu em fotos e planejamento digital para obtenção de um desenho digital do sorriso individual e harmonioso. De acordo com os princípios de máxima conservação da estrutura dentária, as restaurações existentes nos dentes superiores anteriores foram criteriosamente removidas para minimizar a redução do esmalte, seguido do estudo de cor e sombra dos dentes considerando fatores como matiz, croma, valor, opacidade, translucidez e efeitos de luz. Oito facetas diretas foram realizadas em resina composta considerando as propriedades ópticas do material e a influência destas na espessura das camadas de resina para criar efeitos de luz singulares quando sobrepostas. Para a execução de uma odontologia estética e consciente, em associação a um protocolo de trabalho previsível, os sistemas de resinas compostas nanohibridas possibilitam resultados estéticos satisfatórios, evitando tratamentos mais invasivos de maneira economicamente viável.(AU)

Evaluation of surface roughness and color change of bovine enamel after immersion in dye solution

Aim: The aim of this in vitro study was to evaluate the influence of dye solution on enamel color change after bleaching protocols and the effectiveness in maintaining the color of these agents. Material and Methods: The buccal surfaces of sixty-five bovine incisors were cleaned and polished, and the enamel specimens were divided into thirteen groups: G1 to G6: treated with 6% hydrogen peroxide using different surface agents; G7 to G12: treated with 15% hydrogen peroxide using different surface agents; G13: control. After 24 hours, the groups treated were immersed in black tea solution; the control group was stored in artificial saliva. The color was evaluated prior to bleaching, 24 hours later and after immersion in the dye solution; the roughness was measured immediately after bleaching, 24 hours later and 7 days after immersion in the dye solution. The data was analyzed using the Kruskal-Wallis test, followed by the Miller test for roughness analysis, and the Duncan test for color change analysis. It was used 5% significant level with p<0.05. Results: The data found in the evaluation of surface roughness after bleaching indicated a reduction of roughness in all the groups. The surface agent Bifluoride, when applied, showed an increase in roughness after its application and it decreases after immersion in dye solution; the surface agent Desensibilize and the XP Bond adhesive showed greater color alteration after immersion in dye solution. Conclusions: All the groups studied, under different whitening technique, were effective in promoting whitening.

Marginal adaptation in proximal cavities restored with composites and other materials / Adaptação marginal em cavidades proximais com compósitos e outros materiais

Objective: To evaluate the marginal adaptation, in enamel (E) and dentin (D), of composite resin (CR) associated with flowable resin composite (flow), bulk fill flowable base (bulk) and resin modified glass ionomer cement (RMGIC) in slot cavities. Material and Methods: The study was conducted after approval (Protocol No. 21148413.4.0000.5417) from Ethics Committee. Forty extracted human molar teeth were randomly assigned in eight experimental groups: E-CR, E-BULK, E-FLOW, E-RMGIC, D-CR, D-BULK, D-FLOW, D-RMGIC. The occlusal surface was planned, two slot cavities with standard sizes (depth: 2.0 mm, height: 2.5 mm, width: 2.0 mm) were created on a machine for making cavities. The teeth were restored and after 24h subjected to 2000 cyclic loading and sectioned for analysis of marginal adaptation by scanning electron microscopy (SEM). The micrographs were analyzed with the Image J program to measure the size of marginal gaps. The data were transformed into percentages (%GAPS = LG ÷ LM × 100) and analyzed by 2-way ANOVA followed by the post hoc Tukey test (α=0.05). Results: There was a significant difference between different treatments (p0.05). Conclusions: It was concluded that restorations with flowable composite resin and bulk fill liners exhibit the same behavior, but the RMGIC liner increased marginal gap (AU)

Objetivo: Avaliar a adaptação marginal, em esmalte (E) e dentina (D), de restaurações com resina composta (RC) associada a resina composta fluida (flow), resina bulk fill (bulk) e cimento de ionômero modificado por resina (CIVMR) em cavidades tipo slot. Materiais e Métodos: O estudo foi realizado após aprovação no Comitê de Ética e Pesquisa (Protocolo no. 21148413.4.0000.5417). Quarenta molares humanos foram aleatoriamente distribuídos em oito grupos experimentais: E-RC, E-BULK, E-FLOW, E-CIVMR, D-RC, D-BULK, D-FLOW, D-CIVMR. A superfície oclusal foi planificada e duas cavidades tipo slot com tamanhos padronizados (profundidade: 2,0 mm, altura: 2,5 mm, largura: 2,0 mm) foram realizadas em uma máquina para confecção de cavidades. Os dentes foram restaurados e, após 24h, submetidos a 2000 ciclos mecânicos e foram seccionados para análise da adaptação marginal em microscopia eletrônica de varredura (MEV). As micrografias foram analisadas através do programa Image J para medir as fendas marginais. Os dados foram transformados em porcentagens (%fendas = largura da fenda / largura da margem x 100) e analisados através do teste ANOVA-2 critérios seguido do teste de Tukey (α=0,05). Resultados: Houve diferença significante entre os diferentes tratamentos (p0,05). Conclusões: Concluiu-se que as restaurações com base de resina flow e bulk fill exibiram o mesmo comportamento, mas a base de CIVMR aumentou a fenda marginal. (AU)

Pulp Chamber Heating: An In Vitro Study Evaluating Different Light Sources and Resin Composite Layers

Abstract The aim of the present in vitro study was to evaluate the temperature variation inside the pulp chamber during light-activation of the adhesive and resin composite layers with different light sources. Cavities measuring 8x10 mm were prepared on the buccal surface of bovine incisors, leaving a remaining dentin thickness of 1 mm. Specimens were placed in a 37±1 °C water bath to standardize the temperature. The temperature in the pulp chamber was measured every 10 s during 40 s of light activation of the adhesive system (SBMP-3M/ESPE) and in the three consecutive 1-mm-thick layers of resin composite (Z250-3M/ESPE). Three light source devices were evaluated: Elipar 2500 (QTH), LD Max (LED low irradiance) and VALO (LED high irradiance). The results were submitted to one-way ANOVA with repeated measures and Tukey's test, both with p<0.001. The exothermic reaction warming was observed in the Z250 increments, but not in the SBMP. The high irradiance LED showed a higher temperature average (42.7±1.56 °C), followed by the quartz-tungsten-halogen light (40.6±0.67 °C) and the lower irradiance LED (37.8±0.12 °C). Higher temperature increases were observed with the adhesive and the first resin composite increment light-activation, regardless of the employed light source. From the second increment of Z250, the restorative material acted as a dispersive structure of heat, reducing temperature increases. Regardless the light source and restorative step, the temperature increased with the irradiation time. It may be concluded that the light source, irradiation time and resin composite thickness interfered in the temperature variation inside the pulp chamber.

Resumo O objetivo do presente estudo in vitro foi avaliar a variação de temperatura dentro da câmara pulpar durante a fotoativação de um sistema adesivo e de camadas de resina composta com diferentes fontes de luz. Cavidades com dimensões de 8x10 mm foram preparadas na superfície vestibular de incisivos bovinos deixando uma espessura de dentina remanescente de 1 mm. Os espécimes foram inseridos em uma cuba térmica com água à temperatura de 37±1 °C. A temperatura no interior da câmara foi medida a cada 10 s durante 40 s de ativação de luz do sistema adesivo (SBMP; 3M/ESPE) e três camadas de 1 mm de espessura consecutivas de resina composta (Z250; 3M/ESPE ). Três fonte de luz foram avaliadas: Elipar 2500 (QTH), LD Max (LED de baixa densidade de potência), VALO (LED alta densidade de potência). Os resultados foram submetidos a ANOVA de medidas repetidas a um critério e teste de Tukey (ambos com p<0,01). O aquecimento da reação exotérmica foi observado nos incrementos de resina composta, mas não no sistema adesivo. O LED de alta densidade de potência mostrou uma média de temperatura mais elevada (42,7±1,56 °C) seguido pela luz halogéna (40,6±0,67 °C) e o LED de menor densidade de potência (37,8±0,12 °C). Maiores aumentos de temperatura foram observados na fotoativação do sistema adesivo e do primeiro incremento de resina composta, independente da fonte de luz utilizada. A partir do segundo incremento de resina composta, o material restaurador agiu como estrutura dispersiva de calor, reduzindo o aumento de temperatura. Independente da fonte de luz e da etapa restauradora, a temperatura aumentou com o tempo de irradiação. Pode-se concluir que a fonte de luz, o tempo de irradiação, a espessura resina composta interferiram na variação de temperatura no interior da câmara pulpar.

Effect of Two Antioxidants Agents on Microtensile Bond Strength to Bleached Enamel

Abstract This in vitro study evaluated the effect of sodium bicarbonate and sodium ascorbate on the microtensile bond strength of an etch-and-rinse system to bleached bovine enamel. Sixty bovine enamel blocks (4x4 mm) were flattened and randomly allocated into 5 groups: G1 (negative control): without treatment; G2 (positive control): bleached with 35% hydrogen peroxide (HP); G3: bleached and stored for 7 days in artificial saliva before restorative procedures; G4: bleached and treated with 10% sodium bicarbonate solution for 5 min; G5: bleached and treated with 10% sodium ascorbate hydrogel for 15 min. HP gel was applied twice (20 min each, except in G1) and the adhesive restorations were performed. After 24 h, the specimens were sectioned into sticks and submitted to microtensile bond strength testing with a crosshead speed of 0.5 mm/min (n=12). As a complementary visual observation, the enamel surfaces of the G1 and G2 specimens were evaluated with scanning electron microscopy. Data were analyzed by one-way ANOVA (p<0.05). The means (standard deviation) were: G1: 24.22±7.74; G2: 18.29±5.88; G3: 40.88±7.95; G4: 19.95±5.67 and G5: 24.43±6.43. Adhesive failures were predominant in all groups. The comparison between the treatments indicates that waiting 7 days after bleaching is still the most effective approach. When this waiting period is not possible, application of sodium ascorbate or sodium bicarbonate seems to be a good alternative. Therefore, the practicality of obtaining sodium bicarbonate in the bleaching kits and its higher stability enables its clinical use.

Resumo Este estudo in vitro avaliou o efeito do bicarbonato de sódio e do ascorbato de sódio na resistência de união de um sistema adesivo convencional unido ao esmalte bovino clareado. Sessenta blocos de esmalte bovino (4x4 mm) foram planificados e distribuídos aleatoriamente em 5 grupos: G1: (controle negativo); G2 (controle positivo): clareamento com peróxido de hidrogênio 35% (HP); G3: clareamento com HP seguido de armazenamento por 7 dias em saliva artificial antes do procedimento restaurador; G4: clareamento com HP seguido de tratamento com a solução de bicarbonato de sódio 10% por 5 min; G5: clareamento com HP seguido de tratamento com hidrogel de ascorbato de sódio 10% por 15 min. O HP foi aplicado duas vezes (20 min cada, com exceção do grupo G1) e então as restaurações adesivas foram realizadas. Após 24 h, os espécimes foram seccionados em palitos e submetidos ao teste de resistência de união a uma velocidade de 0,5 mm/min (n=12). As superfícies de esmalte de G1 e G2 foram avaliadas com microscopia eletrônica de varredura para fins de análise visual complementar. Os dados foram analisados por ANOVA a um critério (p<0,05). As medias (desvio-padrão) foram: G1: 24,22±7,74; G2: 18,29±5,88; G3: 40,88±7,95; G4: 19,95±5,67 e G5: 24,43±6,43. Falhas adesivas foram predominantes em todos os grupos. A comparação entre os diferentes tratamentos indica que esperar 7 dias após o clareamento é ainda a abordagem mais eficaz. Nos casos em que este período de espera não é possível, a aplicação do ascorbato de sódio e do bicarbonate de sódio parecem ser boas alternativas. Entretanto, a praticidade na obtenção da solução de bicarbonato de sódio nos kits de clareamento e sua maior estabilidade favorecem o seu uso clínico.

Evaluation of temperature increase during in-office bleaching

ABSTRACT The use of light sources in the bleaching process reduces the time required and promotes satisfactory results. However, these light sources can cause an increase in the pulp temperature. Objective The purpose of the present study was to measure the increase in intrapulpal temperature induced by different light-activated bleaching procedures with and without the use of a bleaching gel. Material and Methods A human maxillary central incisor was sectioned 2 mm below the cementoenamel junction. A K-type thermocouple probe was introduced into the pulp chamber. A 35% hydrogen peroxide bleaching gel was applied to the vestibular tooth surface. The light units used were a conventional halogen, a hybrid light (only LED and LED/Laser), a high intensity LED, and a green LED light. Temperature increase values were compared by two-way ANOVA and Tukey´s tests (p<0.05). Results There were statistically significant differences in temperature increases between the different light sources used and between the same light sources with and without the use of a bleaching gel. The presence of a bleaching gel generated an increase in intra-pulpal temperature in groups activated with halogen light, hybrid light, and high intensity LED. Compared to the other light sources, the conventional halogen lamp applied over the bleaching gel induced a significant increase in temperature (3.83±0.41°C). The green LED unit with and without gel application did not produce any significant intrapulpal temperature variations. Conclusion In the present study, the conventional halogen lamp caused the highest increase in intrapulpal temperature, and the green LED caused the least. There was an increase in temperature with all lights tested and the maximum temperature remained below the critical level (5.5°C). The addition of a bleaching gel led to a higher increase in intrapulpal temperatures.

A simplified restorative technique of fractured maxillary anterior teeth

Introduction: Fractures of the anterior teeth consists of a clinical condition that generates not only aesthetic and psychological problems, but may also cause dental pain. Thus, the affected teeth should be treated as urgencies in dental offices and their resolution whenever possible should be in a single session. Direct resin composite restorations should wherever possible be preferred due to the speed and possibility of obtaining good results. Objective: The objective of this case report is to describe the clinical sequence for restoration of a maxillary central incisor that presented a crown fracture using an immediate insert technique for resin composite (a "free hand" technique) with a modification to obtain dentin layer. Case report: A patient sought treatment after she fractured tooth #21. The restoration was performed with resin composite using the immediate technique. To facilitate the layering technique, the immediate insertion technique was changed for making the dentin lobes with the aid of a Teflon tape and the support with the index finger. Conclusion: The restoration of fractured anterior teeth can be performed quickly with the use of resin composites of different opacities and the use of the technique of immediate insertion proposed in this case report.

Influence of pH, bleaching agents, and acid etching on surface wear of bovine enamel

ABSTRACT Development of new materials for tooth bleaching justifies the need for studies to evaluate the changes in the enamel surface caused by different bleaching protocols. Objective The aim of this study was to evaluate the bovine dental enamel wear in function of different bleaching gel protocols, acid etching and pH variation. Material and Methods Sixty fragments of bovine teeth were cut, obtaining a control and test areas. In the test area, one half received etching followed by a bleaching gel application, and the other half, only the bleaching gel. The fragments were randomly divided into six groups (n=10), each one received one bleaching session with five hydrogen peroxide gel applications of 8 min, activated with hybrid light, diode laser/blue LED (HL) or diode laser/violet LED (VHL) (experimental): Control (C); 35% Total Blanc Office (TBO35HL); 35% Lase Peroxide Sensy (LPS35HL); 25% Lase Peroxide Sensy II (LPS25HL); 15% Lase Peroxide Lite (LPL15HL); and 10% hydrogen peroxide (experimental) (EXP10VHL). pH values were determined by a pHmeter at the initial and final time periods. Specimens were stored, subjected to simulated brushing cycles, and the superficial wear was determined (μm). ANOVA and Tukey´s tests were applied (α=0.05). Results The pH showed a slight decrease, except for Group LPL15HL. Group LPS25HL showed the highest degree of wear, with and without etching. Conclusion There was a decrease from the initial to the final pH. Different bleaching gels were able to increase the surface wear values after simulated brushing. Acid etching before bleaching increased surface wear values in all groups.

Variação da temperatura intra-câmara pulpar em função da ativação com LED de géis clareadores de uso ambulatorial / Variation of temperature in pulp chamber due to LED bleaching gels activation

Este estudo avaliou o efeito da aplicação de diferentes géis clareadores na temperatura intra-câmara pulpar no clareamento fotoativado em consultório. Preencheu-se a câmara pulpar de um incisivo com pasta térmica e um sensor digital Termopar, e a raiz submersa em água a 37°C. Avaliaram-se 6 grupos: G1- SG: sem gel; PH: G2- peróxido de hidrogênio incolor a 35%; G3- OXB: Opalescence Xtra Boost; G4- WHP: Whiteness HP; G5- WM: Whiteness HP MAXX; G6- LP: Lase Peroxide. Para a ativação dos géis empregou-se o aparelho LED por 3 minutos. A aferição da variação de temperatura intra-câmara foi realizada com termômetro digital com termopar tipo K a cada 30 segundos. Os dados foram submetidos à ANOVA a dois critérios e teste de Tukey. Os resultados foram: 60 s - O grupo G2 (38° C) apresentou menor valor que os demais; 90 s - G2 (38,8°C) < G6 (39,6°C), G3 (39,8°C); 120 s - G2 (38,8°C) < G3 (40°C), G4 (39,6°C), G5 (39,8°C), G6 (40°C); 150 s - G2 (39°C) < G1 (39,8°C) G3, G4, G5, G6 (40°C); 180 s. A média final obtida foi: G2 (38,72°C) < G5 (39,16°C) < G1 (39,27°C) < G4 (39,30°C) < G6 (39,33°C) < G3 (39,47°C). O gel incolor não promoveu aumento significante na temperatura intrapulpar; géis clareadores com corante vermelho e verde aceleram este aumento quando ativados por luz LED azul de alta densidade de energia...

This study has evaluated the effect of different dental bleaching gels over the pulp chamber temperature during in-office photoactivated dental bleaching. The empty pulp chamber of an incisor was filled with a heat sink compound and a thin digital K-type thermocouple, immersed in distilled water at 37°C. Six groups were evaluated: G1 with no gel; G2 colorless gel; G3- OXB: Opalescence Xtra Boost; G4- WHP: Whiteness HP; G5- WM: Whiteness HP MAXX; G6- LP: Lase Peroxide. The gel light activation was made using LED, during 3 consecutive minutes. The intra-pulpal temperature was measured using a digital thin K-type thermocouple K at every 30 seconds. Data were submitted to ANOVA and TukeyÆs test. Results showed: 60 s -G2 (38°C) showed lower value than the others; 90s -G2 (38.8°C) < G6 (39.6°C), G3 (39.8°C); 120 s - G2 (38.8°C) < G3 (40°C), G4 (39.6°C), G5 (39.8°C), G6 (40°C); 150 s - G2 (39°C) < G1 (39.8°C) G3, G4, G5, G6 (40°C); 180 s. The final mean obtained was: G2 (38,72°C) < G5 (39,16°C) < G1 (39,27°C) < G4 (39,30°C) < G6 (39,33°C) < G3 (39,47°C). The colorless gel did not provided significant increase in the pulp chamber temperature; bleaching gels with red and green dyes accelerate this increase in temperature when activated by blue LED light with high energy density...

Whitening gel and light source influence on pulp chamber temperature

Introduction: The chemical injury caused to the pulp by the penetration of the whitening gel is already known, but another possible cause may be the heat generated by the irradiation of the whitening gel with light sources to accelerate the whitening reaction. Objective: To evaluate in vitro the temperature increasing in the pulp chamber during in-office bleaching with different gel concentrations and light sources. Material and methods: A maxillary human central incisor was used in the 6 groups evaluated. The specimen was sectioned 3 mm apical to the cementoenamel junction. The root canal and pulp chamber were cleaned and widened with a diamond bur to receive the sensor of a thermocouple thermometer. The following hydrogen peroxide gel concentrations were evaluated: 35%, 25%, 15%, and 10%; and the following light sources were applied: blue hybrid LED/laser and violet hybrid LED/laser. The specimen bleaching was repeated 6 times per group. As a control, the temperature was measured with the application of light, without applying any gel. Results were evaluated with one-way ANOVA and Tukey's test (α = 5%). Results: Significant differences between groups were observed (p < 0.05). The blue LED without the gel induced the smallest heat (37.5 ± 0.2) and the blue LED with 15% gel caused the highest heat (38.2 ± 0.3). The combination of violet LED with the 10% gel caused no significant increase in temperature compared to the control in which light was used without gel (p> 0.05). Conclusion: No increase in pulp chamber temperature was higher than 2°C.

Intra pulp chamber temperature variation caused by Nd: YAG and Diode LASER irradiation / Variação da temperatura intracâmara pulpar provocada pela irradiação com laser de Diodo e Nd: YAG

A irradiação com LASER de Neodímio (Nd:YAG) e de Diodo sobre sistemas adesivos pode aumentar a resistência de união em dentina, no entanto a existe a preocupação com a variação de temperatura intracâmara pulpar. O objetivo deste trabalho foi avaliar a variação da temperatura intracâmara pulpar após a aplicação dos sistemas adesivos e subsequente a irradiação com LASER de diodo e Nd:YAG. Material e Métodos: Este estudo apresentou um desenho experimental fatorial com dois fatores: LASER em dois níveis (Diodo [D] e Nd:YAG [N]) e sistema adesivo em quatro níveis (Adper™ Scotchbond™ Multi-Purpose [MP], Adper™ SingleBond 2 [SB], Clearfil™ SE Bond [CSE] e Adper™ Easy One [EO]). A variável de resposta quantitativa foi a variação da temperatura (∆t) em ºC .Utilizou-se 40 dentes bovinos, separados em 8 grupos (n=5), a superfície vestibular foi desgastada até 1 mm de espessura. Depois da aplicação de cada sistema adesivo, mas previamente a fotopolimerização, os espécimes eram irradiados com LASER de diodo e Nd:YAG com parâmetro padronizados. A ∆t foi obtida com um termopar inserido intracâmara pulpar. Os valores obtidos foram submetidos ao teste ANOVA a 2 critérios seguido de Tukey para comparações individuais(p<0,05). Resultados: A média e o desvio padrão da ∆t obtidos foram: N-MP: 12.60 (± 2.51), N-SB: 10.40 (± 5.03), N-CSE: 11.80 (± 5.12) e N-EO: 10.20 (± 2.39), D-MP: 4.4 (± 1.82), D-SB: 5.20 (± 1.54), D-CSE: 4.60 (± 1.14), D-EO: 3.60 (± 1.52). Conclusão: O tipo de sistema adesivo não foi significante no aquecimento gerado pela irradiação com LASER, mas o LASER de Nd:YAG pode fornecer um potencial maior para causar danos a pulpar...

Neodymium (Nd:YAG) and Diode LASER irradiation on adhesive systems canincrease bond strength to dentin, however, concerns about the temperature variation inside pulp chamber still remain. The aim of this study was to evaluate the intra pulp chamber temperature variation caused by irradiation with Nd:YAG or Diode LASER on different adhesive systems. Material and Methods: This study presented experimental design with two factors: LASER on two levels (Diode [D] and Nd:YAG [N]) and adhesive system on four levels (Adper™ Scotchbond™ Multi-Purpose [MP], Adper™ SingleBond 2 [SB], Clearfil™ SE Bond [CSE] and Adper™ Easy One [EO]). The quantitative response variable was the temperature variation (∆t) in ºC. Forty bovine teeth, distributed into 8 groups (n = 5), had the buccal surface flattened up to1 mm thickness of dentin. After the application of each adhesive system, but previously to the light curing, specimens were irradiated with Nd:YAG or Diode LASER with standardized parameters. The ∆t was obtained through a thermocouple inserted into pulp chamber. The values of ∆t were submitted to two-way ANOVA, followed by Tukey (p < 0.05) for individual comparisons. Results: The means (± standard deviation) of ∆t were: N-MP: 12.60 (± 2.51), N-SB: 10.40 (± 5.03), N-CSE: 11.80 (± 5.12) and N-EO: 10.20 (± 2.39), D-MP: 4.4 (± 1.82), D-SB: 5.20 (± 1.54), D-CSE: 4.60 (± 1.14), D-EO: 3.60 (± 1.52). Conclusion: The type of adhesive system was not significant in temperature changes generated by LASER irradiation, but Nd:YAG LASER may provide a higher potential to cause pulp damage...

Resin composite build-ups for complementing multidisciplinary esthetic and functional dental treatments: a case report / Reconstruções em resina composta como complemento de tratamentos multi-disciplinares estéticos e funcionais: relato de caso

Discrepâncias na forma e no posicionamento de dentes anteriores representam desconforto estético para muitos pacientes. Reconstruções em resina composta, mesmo sendo consideradas procedimentos práticos e conservadores, em alguns casos, necessitam de uma complementação interdisciplinar com aparatos ortodônticos para otimizar os resultados estéticos e funcionais. Este relato de caso descreve a gestão de um quadro de queixa estética de um paciente com comprometimento da qualidade de vida. O correto diagnóstico e tratamento com uma estratégia interdisciplinar são destaque para oferecer um tratamento viável e promissor...

Discrepancies in tooth shape and placement of the anterior teeth represent an uncomfortable esthetic scenario for many patients. Even the current composite resin proximal build-up is considered to be practical and conservative, and in some cases, an interdisciplinary approach with orthodontics optimizes the functional and esthetic results. This case report describes the management of a patient with complaint of the anterior esthetic, which compromised her quality of life. The correct diagnosis and the treatment with an interdisciplinary strategy are highlighted to offer a reliable and promissory treatment...