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.

Abstract The aim of this paper was to present a summary of the process of developing and preparing the final documents of the national consensus for teaching undergraduate Brazilian dental students the dental caries curriculum in the Portuguese language. The final document was developed in three steps: a) The ABENO and LAOHA cariology group invited experts from all five regions of Brazil to participate in the discussion. The theoretical support for crafting the first draft of the consensus was based on two publications: National Curriculum Guidelines of the Dentistry graduation in Brazil, Ministry of Education (2021) and the competences described in the European Core Curriculum for Cariology (ORCA-ADEE, 2011); b) The group of experts was divided into 5 working groups: G1-Domain, Main and Specific Competences, G2-Essential knowledge, G3-Life course perspective, G4-Social determinants and dental caries, G5- Glossary. The document was finalized by thoroughly reviewing the process using Delphi methodology; c) The 5-chapter document (one from each working group) was submitted to three open public consultations in 2022 (May-June, August, and October) using Google-forms. The suggestions (content/wording) were discussed within the group as: totally accepted, partially accepted, and rejected. A total of 192 suggestions were registered from 31 dental schools in all regions of Brazil. The number of suggestions received per Group were: 84, 28, 26, 24, 30 suggestions for G1, G2, G3, G4 and G5, respectively. The majority of suggestions were totally accepted by the group of experts (n = 172, 89.6%), 15 were partially accepted (7.8%), and 5 were rejected. Conclusion The final document could be considered to be the first national consensus for teaching the dental caries curriculum in Brazil.

Abstract Objectives To analyze the effect of 5 toothpastes containing different percentages of S-PRG fillers compared to NaF toothpaste and NaF varnish on the dentin hydraulic conductance (Lp). Methodology Dentin disks (1.0±0.2 mm thickness) were cut from third molars, and their Lp values were evaluated using Flodec. The specimens were allocated into 7 groups (n=8). The minimum (smear layer) and the maximum (after acid etching) Lp values were recorded. Lp was also assessed after treatment with either a 0wt.%, 1wt.%, 5wt.%, 20wt.%, or 30wt.% S-PRG toothpaste, a NaF toothpaste, or a NaF varnish. Toothpastes were applied by brushing for 15 s, allowing it to settle for 1 min, and rinsing with deionized water. The NaF varnish was applied for 4 min and was removed with a probe. Specimens were exposed to citric acid (6%, pH 2.1, 1 min) and their final Lp was recorded. The pH of all products was recorded (n=3) and specimens from each group were analyzed by Laser Scanning Confocal Microscopy (LSCM). Data were subjected to 2-way repeated measures ANOVA and post-hoc Bonferroni (a=0.05). Results The highest Lp reduction was noticed for the 5wt.% S-PRG toothpaste, NaF toothpaste, and NaF varnish. However, the toothpastes containing 5wt.%, 20wt.%, and 30wt.% of S-PRG were similar to all toothpastes but differed from the NaF varnish. After erosion, all groups retrieved their maximum Lp values, except for the NaF varnish. The LSCM evidenced deposits on the surface of specimens treated with 5%, 20%, and 30% S-PRG-based toothpastes and NaF toothpaste. Even more deposits were observed for the NaF varnish. After the erosive challenge, the deposits were diminished in all groups. Conclusion Toothpastes containing 5wt.%, 20wt.%, and 30wt.% of S-PRG fillers behaved similarly to a conventional NaF toothpaste, even after an erosive challenge. The NaF varnish promoted better reduction of the Lp, but its effect was also diminished after erosion.

Abstract This was a retrospective cohort study to investigate the impact of COVID-19 pandemic on the gender gap in articles submitted to three international dental journals based in Brazil. All submissions performed to Brazilian Dental Journal, Brazilian Oral Research, and Journal of Applied Oral Science before (2019) and during the pandemic (2020) were assessed. Gender of the first, last, and corresponding authors were collected. Other variables collected were journal, continent studied by authors and stage of their careers (classified according to authors’ highest degree), and final decision reached in the article. Absolute and relative frequencies with 95% confidence intervals, Pearson’s Chi-square tests, and Fisher’s Exact test were used (α = 0.05). In total, 4,726 unique submissions were analyzed. A higher proportion of early-career authors was observed during the pandemic (44.8% to 49.3%, p = 0.021). Most articles were rejected but without association with gender. Increased proportion of male first authors from before to during the pandemic was observed (39% to 42.1%, p = 0.034). Drop in the proportion of articles with women as first authors was observed for researchers in their early- (65.9% to 58.8%, p = 0.02) and mid-career stages (63% to 55.8%, p = 0.014). Reduction in women as first authors was observed during the pandemic in South and Central Americas (66.7% to 61.5%, p = 0.010), and when the last author was a female, or the corresponding author was a male. In conclusion, a disproportionate impact on female dental researchers in submitting articles in the period from before to during the pandemic was observed when considering first authorship, suggesting that the COVID-19 may have increased the gender inequality in dental science.

Abstract Proanthocyanidin has been shown to be efficient in inhibiting matrix metalloproteinases. Objective The aim of this in situ study was to evaluate the protective effect of Proanthocyanidin-based mouthrinses either with naturally acidic or with a neutral pH applied on dentin subjected to erosion. Methodology Eight volunteers wore one palatal device in two phases (7 days washout) with 16 samples per group (n=8). The groups under study were: First Phase/ G1 – 10% proanthocyanidin mouthrinse (pH 7.0, Experimental group 1 – Purified Grape Seeds Oligomeric Proanthocyanidins), G2 – 10% proanthocyanidin mouthrinse (pH 3.0, Experimental group 2 – Purified Grape Seeds Oligomeric Proanthocyanidins). Second Phase/ G3 – 0.12% chlorhexidine mouthrinse (pH 7.0, Positive control group), G4 – no previous treatment (Negative control group). Each device was subjected to 3 erosive cycles (5 minutes) per day for 5 days. Treatments with different mouthrinses were applied once after the second erosive challenge (5 minutes). Profilometry was used to quantify dentin loss (µm). Results Data were analyzed by repeated measures of ANOVA followed by Fisher’s test (p<0.05). G1 (1.17±0.69) and G3 (1.22±0.25) showed significantly lower wear values with no statistical difference between them. G2 (2.99±1.15) and G4 (2.29±1.13) presented higher wear values with no significant differences between them. Conclusion The 10% proanthocyanidin mouthrinse (pH 7.0) could be a good strategy to reduce dentin wear progression.

Abstract Non-inferiority randomized clinical trials are indicated when it is intended to prove that an experimental group is not inferior to a control group by more than a margin of non-inferiority. However, this type of study differs from traditional randomized clinical trials (superiority studies) because they have particularities that impact on the formulation of hypothesis to be tested, experimental design (non-inferiority margin determination, adapted sample size calculation, sensitivity of the study and data final analysis) and also on the presentation of data when writing the manuscript. Therefore, this article aims to present and discuss the particularities of non-inferiority clinical studies, since these requirements are fundamental to guarantee the validity of the conclusions of this type of study.

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.

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 objetivo deste trabalho foi avaliar a resistência de união e permeabilidade da interface de pinos de fibra de vidro nos diferentes terços da dentina intrarradicular (cervical, médio e apical) submetidos a diferentes agentes irrigantes. Noventa dentes unirradiculares humanos foram submetidos ao tratamento endodôntico e foram divididos em cinco grupos de acordo com os agentes irrigantes: água destilada, hipoclorito de sódio 5,25%, ácido poliacrílico 25%, clorexidina 2% e dispersão de nanopartícula de prata à 23 ppm. Os grupos foram divididos em 3 subgrupos (n=6) de acordo com a técnica adotada para cimentação adesiva dos pinos de fibra de vidro: Grupo SBU: sistema adesivo ScotchbondTM Universal + cimento resinoso RelyX ARC; Grupo U200: cimento resinoso autoadesivo RelyX U200; Grupo MCE: cimento resinoso autoadesivo Maxcem Elite. A resistência de união e a permeabilidade da interface foram mensurados em diferentes áreas da dentina intrarradicular. Os dados foram submetidos a ANOVA e teste de Fisher (a=0,05). Amostras representativas foram levadas à microscopia eletrônica de varredura. A solução de nanopartícula de prata apresentou os maiores valores de resistência de união em todos os terços analisados para o grupo SBU. No grupo U200, os maiores valores foram encontrados para a solução de hipoclorito de sódio, com diferença para o ácido poliacrílico. Observou-se uma diminuição nos valores de resistência de união na direção cérvico-apical para o grupo MCE e o mesmo comportamento foram encontrados para os demais grupos. Com relação a permeabilidade da interface, o uso da solução de nanopartícula de prata resultou em menores valores nos terços cervical e apical. Houve diminuição dos valores de resistência de união no sentido cérvico-apical. As diferentes soluções irrigantes, bem como a profundidade intrarradicular influenciaram a resistência de união e permeabilidade da interface dos materiais adesivos ao substrato dentinário. A nanopartícula de prata pode ser utilizada como agente irrigador do conduto radicular previamente à cimentação de pinos de fibra de vidro.

Abstract The aim of this study was to evaluate the push-out bond strength and interface permeability of glass-fiber posts in different regions of post space (cervical, middle, and apical) submitted to different irrigation solutions. Ninety single-rooted human teeth were submitted to endodontic treatment and divided into five groups, according to irrigation solutions: distilled water, 5.25% NaOCl, 25% polyacrylic acid, 2% chlorhexidine, and 23 ppm Ag NP dispersion. Each group was divided in 3 subgroups (n=6) according to cementation: SBU: Adper Scotchbond Universal + RelyX ARC; U200: RelyX U200; MCE: MaxCem Elite. Bond strength and sealing ability were measured in different areas of post space. The data was subjected to ANOVA and Fisher’s test (a=0,05). The silver nanoparticle solution showed highest bond strength values and lowest interface permeability in all thirds analyzed for SBU group. In the U200 group, the highest bond strength values were found for sodium hypochlorite solution, with significant difference between this solution and polyacrylic acid. A decrease in bond strength values in cervical to apical direction was found for MCE group and the same behavior were found for others groups. Regarding interface permeability, use of silver nanoparticle solution resulted in lower values in cervical and apical thirds. There was a decrease in bond strength in cervical to apical direction. Different irrigation solutions and intraradicular depth influenced the bond strength and interface permeability of adhesive material to dentin substrate. Silver nanoparticle solution can effectively be used as an irrigation agent in post space prior to fiber post cementation process.

Resumo Este estudo avaliou o impacto de suco de laranja na resistência de união (RU) de sistemas adesivos dentinários (SAD) à superfície do esmalte após a simulação com uma ciclagem erosiva in situ/ex vivo. Cento e noventa e dois fragmentos de esmalte bovino (4x4x2mm) foram obtidos e randomizados considerando a microdureza superficial, e distribuídos em dispositivos palatinos para 8 voluntários, em três fases (uma para cada SAD), contendo 8 blocos, os quais foram alocados em 4 pares. Diariamente, esses pares eram submetidos às seguintes condições extraoralmente: CONT- sem desafio erosivo ou abrasivo; ERO- desafio erosivo somente; ABR- desafio abrasivo somente; e ERO+ABR- com desafio erosivo e abrasivo. A ciclagem erosiva (imersão em suco de laranja, 3 vezes/dia/5 min/5 dias) e/ou ciclagem abrasiva (escova dentária elétrica, 3 vezes/dia/1 min/5 dias) foram feitas. Após estas ciclagens, todos os espécimes foram restaurados com os sistemas adesivos Adper Scotchbond Multi Purpose (MP), Adper Single Bond 2 (SB) ou Clearfil SE Bond (SE), e com a resina composta Filtek Z250. Após 7 dias, palitos (área ≈1 mm) eram obtidos e submetidos ao teste de resistência de união por microtração (μTBS) a 0,5 mm/min. Os dados foram estatisticamente analisados por ANOVA e teste de Tukey (a=0,05). Os modos de fratura foram determinados utilizando um microscópio digital (40×). SAD foi o único fator estatisticamente significante. SE foi o único SAD não afetado por qualquer desafio, enquanto o MP e o SB apresentaram um desempenho de acordo com o cenário. As fraturas do tipo mista e adesiva foram predominantes em todos os grupos. O desempenho geral sugeriu que RU ao esmalte após desafio erosivo/abrasivo por suco de laranja não foi afetada e foi material-dependente.

Abstract This study evaluated the impact of orange juice on the bond strength (BS) of dentin bonding systems (DBSs) to enamel surface after simulation with an in situ/ ex vivo erosive cycling. One hundred and ninety two bovine enamel fragments (4x4x2mm) were obtained and randomized regarding superficial microhardness and distributed to palatal devices for 8 volunteers, in three phases (one for each DBS), containing 8 blocks, which were, allocated in 4 pairs. Daily, these pairs were subjected extraorally to the following conditions: CONT- neither erosive nor abrasive challenge; ERO- erosive challenge only; ABR- abrasive challenge only and ERO + ABR- with erosive and abrasive challenges. Erosive cycles (immersion in orange juice, 3 times/day/5 min/5 days) or/and abrasive challenges (electric toothbrush, 3 times/day/1 min/5 days) were performed. After these cycles, all specimens were restored with the adhesive systems Adper Scotchbond Multi Purpose (MP), Adper Single Bond 2 (SB) or Clearfil SE Bond (SE), and the composite resin Filtek Z250. After 7 days, sticks (area ≅1 mm2) were obtained and subjected to the microtensile bond strength test (μTBS) at 0.5 mm/min. Data was statistically analyzed by ANOVA and Tukey tests (a=0.05). Failure modes were determined using a digital microscope (40´). DBS was the only statistical significant factor. SE was the unique DBS not affected in any challenge, whereas MP and SB performed according to the scenario. The adhesive and mixed failures were predominant in all groups. Overall performance suggested that BS to enamel after erosive /abrasive challenged by orange juice was not affected and it was material-dependent.

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.

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.

ABSTRACT Objective: To evaluate the influence of an application technique of a glass-fiber post using self-adhesive resin cements on the push-out bond strength and the presence of bubbles in the root thirds. The cements were either applied according to the manufacturer's instruction or using a commercial delivering system (Centrix), at which the cement pastes were collected and applied after manipulation. Material and Methods: Self-adhesive resin cements (RelyX U200/3M ESPE-U200; Maxcem Elite/Kerr-MAX; Clearfil SA Cement/Kuraray-CSA) and a conventional cement (RelyX ARC/3M ESPE-ARC) were used to cement a post and applied either based on the manufacturer's instructions or using a Centrix syringe to deliver the cements directly onto the post of choice, or directly into canal. The roots were scanned with a micro-computed tomography (μCT) and then sectioned into nine 1-mm thick slices for a push-out bond strength test. The μCT images showed the percentage of bubbles in the root thirds (cervical, medium, and apical). Data were analyzed with three-way ANOVA/Tukey (α=0.05). Results: Triple interaction was not significant (p>0.05). The interaction “material” vs “root third” was not significant. A significant interaction was observed between “material” vs “application technique” (p<0.05). For ARC, U200, and MAX, significantly lower percentages of bubbles were observed when the Centrix syringe delivered the cements. Equivalent percentages of voids were observed for CSA, irrespective of the application technique (p>0.05). Significantly higher bond strength was observed when the self-adhesive resin cements were applied using the Centrix delivery system, in comparison with the manufacturer's instructions (p<0.05). Bond strength varied with the root third: cervical>medium>apical (p<0.05). No correlations were found between the bond strength and voids. Conclusions: Bond strength and voids are negatively influenced by the conventional application technique for luting fiber posts. The delivery system (Centrix) seems to produce better results when cementing fiber posts.

ABSTRACT Objective This study investigated the effect of the fluorescent dye rhodamine B (RB) for interfacial micromorphology analysis of dental composite restorations on water sorption/solubility (WS/WSL) and microtensile bond strength to dentin (µTBS) of a 3-step total etch and a 2-step self-etch adhesive system. Material and Methods The adhesives Adper Scotchbond Multi-Purpose (MP) and Clearfil SE Bond (SE) were mixed with 0.1 mg/mL of RB. For the WS/WSL tests, cured resin disks (5.0 mm in diameter x 0.8 mm thick) were prepared and assigned into four groups (n=10): MP, MP-RB, SE, and SE-RB. For µTBS assessment, extracted human third molars (n=40) had the flat occlusal dentin prepared and assigned into the same experimental groups (n=10). After the bonding and restoration procedures, specimens were sectioned in rectangular beams, stored in water and tested after seven days or after 12 months. The failure mode of fractured specimens was qualitatively evaluated under optical microscope (x40). Data from WS/WSL and µTBS were assessed by one-way and three-way ANOVA, respectively, and Tukey’s test (α=5%). Results RB increased the WSL of MP and SE. On the other hand, WS of both MP and SE was not affected by the addition of RB. No significance in µTBS between MP and MP-RB for seven days or one year was observed, whereas for SE a decrease in the µTBS means occurred in both storage times. Conclusions RB should be incorporated into non-simplified DBSs with caution, as it can interfere with their physical-mechanical properties, leading to a possible misinterpretation of bonded interface.

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.

Interface integrity can be maintained by setting the composite in a layering technique and using liners. Objective The aim of this in vitro study was to verify the effect of resin-modified glass-ionomer cement (RMGIC) lining and composite layering technique on the bond strength of the dentin/resin adhesive interface of lateral walls of occlusal restorations. Material and Methods Occlusal cavities were prepared in 52 extracted sound human molars, randomly assigned into 4 groups: Group 2H (control) – no lining + two horizontal layers; Group 4O: no lining + four oblique layers; Group V-2H: RMGIC lining (Vitrebond) + two horizontal layers; and Group V-4O: RMGIC lining (Vitrebond) + four oblique layers. Resin composite (Filtek Z250, 3M ESPE) was placed after application of an adhesive system (Adper™ Single Bond 2, 3M ESPE) dyed with a fluorescent reagent (Rhodamine B) to allow confocal microscopy analysis. The teeth were stored in deionized water at 37oC for 24 hours before being sectioned into 0.8 mm slices. One slice of each tooth was randomly selected for Confocal Laser Scanning Microscopy (CLSM) analysis. The other slices were sectioned into 0.8 mm x 0.8 mm sticks to microtensile bond strength test (MPa). Data were analyzed by two-way ANOVA and Fisher's test. Results There was no statistical difference on bond strength among groups (p>0.05). CLSM analysis showed no significant statistical difference regarding the presence of gap at the interface dentin/resin among groups. Conclusions RMGIC lining and composite layering techniques showed no effect on the microtensile bond strength and gap formation at the adhesive interface of lateral walls of high C-factor occlusal restorations.