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Background: Considering the variability of finishing protocols for composite resins, the literature does not offer a consensus about the influence of these approaches to obtain a final polishing and whether the physical properties of these composite resins change at different analysis times. Therefore, the study analyzed the microhardness, roughness, color stability, and gloss of a nanocomposite resin with different finishing, aging with coffee, and repolishing protocols. Material and Methods: Nanocomposite resin samples were divided into three finishing protocol groups: Diamond burs (F and FF), multi-fluted tungsten carbide burs (18 and 30 flutes), and coarse and medium abrasive discs (Soflex-3M). All protocols used spiral rubber tips (F and FF) for polishing. Knoop microhardness (KHN), roughness (Ra), color changes (ΔE00 and YI), and gloss (GU) were analyzed. Scanning electron microscopy provided images of resins and finishing and polishing instruments. Results: Resin KHN (p<0.001) decreased, and Ra (p<0.001), ΔE00 (p<0.001), and YI (p<0.001) increased after aging with coffee, regardless of finishing protocol. Abrasive discs showed lower color changes, YI, and Ra and higher GU. Repolishing restored KHN and Ra but not ΔE00 (p>0.05) and YI (p>0.05). Conclusions: Abrasive disc finishing reduced roughness and yellowness and increased nanocomposite resin gloss after aging with coffee. Key words:Color, Composite resins, Dental materials, Staining, Surface properties.

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Non-carious Cervical Lesions (NCCL) are dental tissue defects, non-related to caries, frequently observed in the dental practice. The aim of this study was to evaluate the effects of NCCL on dentin depth and thickness and the response to dental pain by means of clinical diagnostic tests. 86 teeth from 14 patients with NCCL were assessed by: depth of NCCL, clinical tests (evaporative stimulus, to detect pain levels of dentin hypersensitivity, cold thermal test to classify pulp health, percussive stimuli to evaluate the periradicular tissues and cone beam computed tomography (tomography to evaluate remaining dentin thickness (RDT). In terms of depth, the sample was divided into two groups: G1- teeth with NCCLs ≤1.0mm and G2- teeth with NCCLs between 1.1-2.0 mm. Dental pain data were compared by Mann-Whitney test and RDT by Student's t-test and correlations by the Pearson test (p<0.05). The depth of NCCL does not influence dental pain response to evaporative stimulus (p=0.129), cold thermal test (p = 0.125), vertical (p = 0.317) and horizontal (p = 0.119) percussion clinical diagnostic tests. However, G1 showed more RDT (p<0.001), and the correlation test showed that deeper NCCL presents smaller remaining dentin thickness (p=0.011/r=-0.273). In conclusion, tooth with NCCL up to 2mm-depth presents similar levels of pain for dentin hypersensitivity, pulp and periradicular tissue independent to NCCL depth, however, lesions with ≤1.0mm-depth showed greater RDT in tomographic findings.

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Abstract Non-carious Cervical Lesions (NCCL) are dental tissue defects, non-related to caries, frequently observed in the dental practice. The aim of this study was to evaluate the effects of NCCL on dentin depth and thickness and the response to dental pain by means of clinical diagnostic tests. 86 teeth from 14 patients with NCCL were assessed by: depth of NCCL, clinical tests (evaporative stimulus, to detect pain levels of dentin hypersensitivity, cold thermal test to classify pulp health, percussive stimuli to evaluate the periradicular tissues and cone beam computed tomography (tomography to evaluate remaining dentin thickness (RDT). In terms of depth, the sample was divided into two groups: G1- teeth with NCCLs ≤1.0mm and G2- teeth with NCCLs between 1.1-2.0 mm. Dental pain data were compared by Mann-Whitney test and RDT by Student's t-test and correlations by the Pearson test (p<0.05). The depth of NCCL does not influence dental pain response to evaporative stimulus (p=0.129), cold thermal test (p = 0.125), vertical (p = 0.317) and horizontal (p = 0.119) percussion clinical diagnostic tests. However, G1 showed more RDT (p<0.001), and the correlation test showed that deeper NCCL presents smaller remaining dentin thickness (p=0.011/r=-0.273). In conclusion, tooth with NCCL up to 2mm-depth presents similar levels of pain for dentin hypersensitivity, pulp and periradicular tissue independent to NCCL depth, however, lesions with ≤1.0mm-depth showed greater RDT in tomographic findings.

Resumo Lesões Cervicais Não Cariosas (LCNC) são defeitos do tecido dentário, não relacionados à cárie, frequentemente observados na prática odontológica. O objetivo do estudo foi avaliar os efeitos da profundidade e espessura da dentina de LCNC na resposta à dor dentária por meio de testes de diagnóstico clínico. 86 dentes de 14 pacientes com LCNC foram avaliados por: profundidade da LCNC, testes clínicos (estímulo evaporativo, para detectar níveis de dor de hipersensibilidade dentinária, teste térmico frio para classificar a saúde pulpar, estímulos percussivos para avaliação do tecido perirradicular e tomografia computadorizada de feixe cônico (TCFC), para avaliação da espessura de dentina remanescente (EDR). Em termos de profundidade, a amostra foi dividida em dois grupos: G1- dentes com LCNCs ≤1,0mm e G2- dentes com LCNCs entre 1,1-2,0 mm. Os dados de dor dentária foram comparados pelo teste de Mann-Whitney e a EDR pelo teste t-Student e correlações pelo teste de Pearson (p <0,05). A profundidade da LCNC não influencia a resposta da dor dentária ao estímulo evaporativo (p = 0,129, teste térmico frio (p = 0,125), teste diagnóstico clínico de percussão vertical (p = 0,317) e horizontal (p = 0,119), porém o G1 apresentou maior EDR (p <0,001) e o teste de correlação mostrou que LCNC mais profunda apresenta menor EDR (p = 0,011 / r = -0,273). Conclusão: Dentes com LCNC de até 2mm de profundidade apresenta níveis semelhantes de dor para hipersensibilidade dentinária, pulpar e saúde perirradicular, independente da profundidade da LCNC. Entretanto, lesões com profundidade ≤1,0mmin apresentaram mais EDR nos achados tomográficos.

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This study aimed to evaluate the influence of different bone attachment levels and occlusal loads on the stress distribution pattern of maxillary premolars with or without non-carious cervical lesion (NCCL), before and after restoration with composite resin by three-dimensional (3D) finite element analysis. From the healthy model, NCCL models were produced and the cavity was restored with composite resin. Models with vertical and horizontal bone loss were also made. For each model, three types of occlusal loads were simulated (100 N): vertical load (VL), buccal load (BL), and palatal load (PL). After processing the models, the data were obtained in MPa for the criteria of Maximum Principal Stress (for all structures) and Minimum Principal Stress (for cortical and medullary bones). Stress values were collected for a node on the cervical buccal surface (Maximum Principal Stress) and the buccal crestal bone (Minimum Principal Stress). As a result, the different bone attachment levels did not affect stress distribution at the amelodentinal junction. The buccal load promoted a higher concentration of compressive stress on the buccal bone surface and the palatal load resulted in greater tensile stress in the buccal cervical third of the tooth. The concentration of tensile stress in the buccal cervical third was exacerbated by the presence of NCCL and it was similar to the healthy and restored models. It can be concluded that stress concentration at the bone level does not depend on the presence or absence of NCCL and the restoration procedure but it is related to the type of occlusal load. However, the presence of NCCL promoted a higher stress concentration in the cervical region, especially when combined with oblique occlusal loads.

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OBJECTIVE: The aim of this study was to evaluate the influence of different light-curing units (LCUs) with distinct tip diameters and light spectra for activating bulk-fill resins. MATERIALS AND METHODS: The specimens (n = 10) were made from a conventional composite (Amaris, VOCO) and bulk-fill resins (Aura Bulk Fill, SDI; Filtek One, 3M ESPE; Tetric Bulk Fill, Ivoclar Vivadent) with two diameters, 7 or 10 mm, × 2 mm thickness. Following 24 hours of specimen preparation, the degree of conversion (DC) was evaluated using the Fourier-transform infrared unit. Knoop hardness (KHN) readings were performed on the center and periphery of the specimens. Data were assessed for homoscedasticity and submitted to one-way and three-way analysis of variance followed by the Tukey's and Dunnett's tests, depending on the analysis performed (α = 0.05). RESULTS: LCUs and specimen diameter significantly affected the DC. The Tetric Bulk Fill provided increased DC results when light-cured with Valo (54.8 and 53.5%, for 7 and 10 mm, respectively) compared with Radii Xpert (52.1 and 52.9%, for 7 and 10 mm, respectively). No significant differences in KHN results were noted for the conventional resin composite (Amaris) compared with LCUs (p = 0.213) or disc diameters (p = 0.587), but the center of the specimen exhibited superior KHN (p ≤ 0.001) than the periphery. CONCLUSION: The light spectrum of the multipeak LCU (Valo) significantly increased the DC and KHN of the bulk-fill resin composite with additional initiator to camphorquinone (Tetric Bulk Fill) compared with the monowave LCU (Radii Xpert). The tip size of the LCUs influenced the performance of some of the resin composites tested.

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OBJECTIVE: This study aimed to evaluate the effect of interval time after acidic beverage intake and brushing on roughness and hardness of resin composite. MATERIALS AND METHODS: Nanofilled resin composites were tested as per interval time (no interval, 15 or 30 minutes) between aging media (isotonic, sports drink) and brushing. Specimens (n = 9) were subjected to three cycles daily for 5 days with immersion in beverage followed by simulated brushing (585 strokes). The brushing (control) group was submitted only in brushing cycles. Roughness and microhardness were analyzed in the baseline and end of the experiment. Surface morphology was analyzed by using scanning electron microscopy (SEM). STATISTICAL ANALYSIS: Data were analyzed by one-way ANOVA and Tukey's honestly significant difference (α = 0.05). RESULTS: Roughness was higher in no interval group and lower in 30 minutes and control. The 15 minutes present no statistical difference between control, 30 minutes and no interval. The hardness not present difference between groups. The SEM showed the no interval more roughness than 15 and 30 minutes, control and baseline. CONCLUSION: The interval time between erosive and abrasive challenge is important to preserve the smoothness surface of composite resin.

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OBJECTIVE: To perform a systematic review of the literature focused to evaluate in vitro function of prefabricated fiber posts with and without customization by additional auxillary fiber posts and composite resin on the fracture strength of wide or enlarged canals and the failure pattern. METHODS: Six databases were used as primary search sources (PubMed, Scopus, LILACS, SciELO, Science Direct, and Web of Science) and three databases (Open Grey, Open Thesis, and OATD) were used to partially capture the "grey literature". The research included laboratory studies that used human upper anterior teeth aiming to assess the fracture strength and failure pattern of different glass fiber post customizations by additional auxiliary fiber posts or composite resin. The search had no restriction of year, language, and publication status. The risk of bias of the studies was assessed from the criteria established in systematic reviews of laboratory studies. Standardized mean differences were calculated by comparing the mean fracture strengths of customized and non-customized posts. Pooled estimates were calculated by Glass' delta method using the random-effects model. Subtotal estimates were presented according to each type of relining procedure and an overall estimate was described considering all studies combined. RESULTS: The search provided 2291 results, from which six met the eligibility criteria and were included in the qualitative assessment of the review. Only three studies presented a moderate risk of bias. The meta-analysis results showed that the use of auxiliary posts produced higher mean fracture strengths than non-customized posts (SMD = 2.21; 95%CI: 0.74; 3.68), and it was more effective than the use of composite resin to reline the posts. CONCLUSION: Based on laboratories studies, even though has not been observed any difference to a statistically significant level on fracture strength and failure pattern of the customized and non-customized post, future studies should follow a standardized approach to implementation and reporting of data.

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On ceramic veneers rehabilitation, teeth with non-carious cervical lesions (NCCLs), especially premolars, are often involved. Preparation to remove deep NCCLs may lead to excessive wear and a less conservative approach, which goes against the current principles of minimal wear and maximum preservation. However, no evidence exists indicating which technique could avoid excessive wear during the dental preparation for veneers associated with NCCL. Thus, this study aimed to present an aesthetic treatment with ceramic veneers and follow-up of 24 months of a patient with various levels of NCCL severity; and to evaluate various wear protocols for dental veneers associated with NCCL via Finite Element Analysis (FEA) to guide and justify the clinical decision of the clinical case described. A 37-year-old male patient presented for treatment with wear on the anterior teeth and with NCCLs of various severity degrees on the posterior teeth. The treatment chosen was rehabilitation with ceramic veneers on teeth 15 to 25. The best restorative approach for the NCCL teeth was evaluated via an FEA, simulating various protocols and lesion depths while also calculating the percentage of tooth structure loss. Restoring the premolar's deeper NCCL with a composite resin core, before a ceramic veneer impression, presented better mechanical behavior in FEA and less tooth wear. For the 1.0 mm NCCL, beveling the lesion promoted good stress distribution, less invasive wear and an easier clinical procedure, as it did not involve a previous restorative procedure. It could be concluded that the restorative decision for premolars with NCCLs that will receive veneers should consider the set biomechanical behavior and especially the tooth structure wear necessary. For the case report presented, after two years of follow-up, no changes from the immediate result were observed, indicating that the cause of the lesions was eliminated, and that the treatment was effective, at least in the short-term. For FEA analysis, restoring the deeper NCCL prior to ceramic veneer impression, presented better mechanical behavior and less tooth wear. For the 1.0 mm NCCL, beveling the margin of the lesion generated the same good results

Na reabilitação com facetas cerâmicas, dentes com lesões cervicais não cariosas (LCNC), especialmente pré-molares, estão frequentemente envolvidos. O preparo para remover a LCNC pode levar a um desgaste excessivo e a uma abordagem menos conservadora, o que vai contra os princípios atuais de mínimo desgaste e máxima preservação. Entretanto, não existem evidências indicando qual técnica pode evitar o desgaste excessivo durante o preparo para facetas associado com LCNC. Portanto, esse artigo tem dois objetivos principais: 1) apresentar um tratamento estético com facetas cerâmicas e acompanhamento de 24 meses de um paciente com vários níveis de severidade de LCNC e 2) avaliar vários protocolos de preparo para facetas cerâmicas associadas com LCNC por meio do Método de Elementos Finitos (MEF) para guiar e justificar a decisão clínica do caso clínico descrito. Um paciente de 37 anos, gênero masculino, compareceu para tratamento com desgaste nos dentes anteriores e com LCNC com vários graus de severidade nos dentes posteriores. Optou-se pela reabilitação com facetas cerâmicas nos dentes 15 a 25. A melhor abordagem restauradora para os dentes com LCNC foi avaliada por MEF, simulando vários protocolos e profundidades de lesão, além disso foi calculada a porcentagem de estrutura dental perdida. Restaurar a LCNC profunda de um pré-molar com um núcleo de resina composta, antes da moldagem para faceta cerâmica, apresentou melhor comportamento mecânico em MEF e menos desgaste dental. Para a LCNC de 1 mm, biselar a lesão promoveu boa distribuição de tensões, um desgaste menos invasivo e um procedimento clínico mais fácil, já que não envolveu um procedimento restaurador prévio. Pode-se concluir que a decisão restauradora para pré-molares com LCNC que irão receber facetas deve considerar o comportamento biomecânico do conjunto e, principalmente, o desgaste de estrutura dental necessário. Para o caso apresentado, após 2 anos de acompanhamento, nenhuma mudança foi observada, indicando que a causa das lesões foi eliminada, e que o tratamento foi efetivo, ao menos no curto prazo. Para MEF, restaurar a LCNC antes da moldagem para facetas, apresentou melhor comportamento mecânico e menor desgaste dentário. Para a LCNC de 1,0 mm, fazer o bisel na margem da lesão levou aos mesmos bons resultados.

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The aim of this study was to evaluate the influence of different anterior load type and restorative procedure on stress distribution of maxillary incisors with different noncarious cervical lesions (NCCLs) morphologies. Three-dimensional models of a maxillary incisor were generated. Beyond the sound model (SO), five NCCLs morphologies were simulated: shallow (SH), notched (NO), concave (CO), wedge-haped (WS) and irregular with dual center (IR' and IR"). Composite resin restoration of all the models was simulated (R). Two different anterior loads were applied: 100N on palatine middle third (ML) and 500 N on palatine incisal third (IL). The data were obtained in MPa using the Maximum Principal Stress and Von Mises criteria and the statistical analysis was performed (paired t-test with 95% confidence level). The IL provided higher compressive stress than ML, mainly on WS (-136.3MPa), IR" (-117.5) and NO (-71.1 MPa). The highest tensile stress found within the restored models was on NOR with IL (19,1 MPa). The Von Mises results showed higher stress concentration on non-restored and IL models (p<0.001). The anterior load type and restorative status were determinant factors on stress distribution pattern changes, whereas NCCLs morphologies had little influence in maxillary incisors.

O objetivo deste estudo foi avaliar a influência de diferentes tipos de contatos anteriores e procedimentos restauradores na distribuição de tensões de incisivos superiores com diferentes morfologias de lesões cervicais não-cariosas (NCCLs). Modelos tridimensionais de um incisivo central superior foram gerados. Além do modelo hígido (SO), foram simuladas cinco morfologias de NCCLs: rasas (SH), entalhadas (NO), côncavas (CO), em forma de cunha (WS) e irregulares com centro duplo (IR' e IR''). Restauração com resina composta em todos os modelos foi simulada (R). Dois contatos anteriores diferentes foram aplicadas: 100N no terço médio palatino (ML) e 500N no terço incisal palatino (IL). Os dados foram obtidos em MPa utilizando os critérios de Tensão Máxima Principal e de Von Mises e a análise estatística foi realizada (teste t pareado com nível de significância de 95%). A IL proporcionou maior estresse compressivo que ML, principalmente em WS (-136,3MPa), IR "(-117,5) e NO (-71,1 MPa). A maior tensão de tração encontrada nos modelos restaurados foi na NOR com IL (19,1 MPa). Os resultados de Von Mises mostraram maior concentração de estresse nos modelos não restaurados e IL (p <0,001). O tipo de contato anterior e a presença de restauração foram fatores determinantes nas alterações do padrão de distribuição de estresse, enquanto as morfologias dos NCCLs tiveram pouca influência nos incisivos superiores.

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Objetivo: avaliar o comportamento biomecânico de pré- -molar superior com presença de Lesões Cervicais Não Cariosas (LCNC) e submetido a três carregamentos oclusais distintos pelo método de elementos finitos tridimensional (3D). Material e método: nove modelos tridimensionais elásticos foram gerados, com propriedades ortotrópicas e isotrópicas: Hígido (H); LCNC não restaurada (LCNC) e LCNC restaurada com resina composta (RC); sendo todos estes modelos submetidos a três carregamentos: Axial (A), Oblíquo vestibular (V) e Oblíquo palatino (P). Os carregamentos tiveram intensidade de 150 N e a restrição de deslocamento foi realizada na base e lateral dos ossos cortical e medular. Os resultados foram gerados em tensão máxima e mínima principal. Resultados: O carregamento axial apresentou padrões de tensão mais favoráveis, independente da característica da região cervical. O carregamento palatino mostrou maior acúmulo de tensão de tração na região cervical vestibular e o carregamento vestibular resultou em maior tensão de compressão na tábua óssea vestibular. A presença de LCNC foi fator intensificador para o aumento da concentração de tensão na região cervical. A simulação da restauração com resina composta promoveu um comportamento biomecânico simular ao do hígido. Conclusões: que o carregamento palatino pode estar mais associado com a presença de LCNCs e o vestibular com a presença de recessão gengival. O ajuste oclusal e a restauração da LCNC são indicados para tornar o padrão de tensão mais favorável para o remanescente dentário.

Objective: to evaluate the biomechanical behavior of maxillary premolar with the presence of NCCL and submitted to three distinct occlusal loads, using the three-dimensional (3D) finite element analysis. Methods: nine three-dimensional elastic models were generated, with orthotropic and isotropic properties: Sound (H); Unrestored NCCL (NCCL) and NCCL restored with composite resin (RC); All models were submitted to three loads: Axial (A), Buccal (V) and Palataline (P). The loads intensity was 150 N and the displacement restriction was performed at the base and lateral of the cortical and medullary bones. The results were generated at maximum and minimum principal stress. Results: the axial loading presented more favorable stress pattern, independent of the characteristic of the cervical region. The palataline loading showed a greater concentration of tensile stress in the buccal cervical region and the buccal loading resulted in a higher compression stress in the buccal bone. The presence of NCCL was a relevant factor for increase concentration of stress in the cervical region. The simulation of the restoration with composite resin promoted a biomechanical behavior similar to that of the sound tooth. Conclusion that the palataline loading may be more associated with the presence of NCCLs and the vestibular with the presence of gingival recession. The occlusal adjustment and the restoration of NCCLs are indicated to produce the stress pattern more favorable for the dental remaining.