Effects of lesion size on the 30-month clinical performance of restorations with bulk fill and a regular nanofilled resin composite in noncarious cervical lesions.

OBJECTIVE: The aim of this double-blind, randomized trial was to evaluate the influence of the occlusogingival distance (OGD) in noncarious cervical lesions (NCCLs) on the clinical performance of a regular bulk-fill resin composite and a regular nanofilled resin composite. MATERIALS AND METHODS: One hundred and forty NCCLs in 77 participants were randomly divided into four groups (n = 35), according to OGD (1.5 mm ± 10% or 3 mm ± 10%) and resin composites (Filtek Bulk Fill Posterior [B] or Filtek Z350 XT [C]), namely: 1.5 mm-B, 1.5 mm-C, 3 mm-B, and 3 mm-C. The restorations were bonded using a two-step self-etch adhesive (Clearfil SE Bond), applied following the manufacturer's instructions. Restorations were polished 1 week after placement. Two experienced and calibrated examiners evaluated the restorations using modified US Public Health Service criteria at baseline (7 days) and after 6, 12, 18, 24, and 30 months. Statistical analyses were carried out using Kruskal-Wallis, Friedman's repeated measures analysis of variance, and the Wilcoxon signed rank test (α = 0.05). RESULTS: After 30 months, the recall rate was 94.2%. Eight restorations were lost (3 for 1.5 mm-C, 2 for 1.5 mm-B, 1 for 3 mm-C, and 2 for 3 mm-B). All groups resulted in a significantly worse marginal discoloration and surface texture at 30 months in comparison with the baseline (1 week). No significant difference was found for the other parameters. CONCLUSION: The restorations performed with both resin composites produced clinically acceptable restorations. The OGD of NCCLs did not influence the clinical performance of restorations. CLINICAL SIGNIFICANCE: The OGD of NCCLs did not have a significant effect on the clinical performance of a regular bulk-fill and nanofilled restorations. Both materials showed a very good performance on 30-month evaluation.

Influence of different intraradicular chemical pretreatments on the bond strength of adhesive interface between dentine and fiber post cements: A systematic review and network meta-analysis.

Systematic review and network meta-analyses were performed to answer the question: Do intraradicular chemical pretreatments affect the bond strength of the adhesive interface between dentine and fiber post cements? A literature search was performed in PubMed, Scopus, Web of Science, LILACS, BBO, and Cochrane Library in October 2018 (updated September 2021). In vitro studies that compared the bond strength assessed by push-out tests following at least two dentine chemical treatments prior to fiber post cementation were included. Risk of bias was evaluated. A random-effects Bayesian-mixed treatment comparison model was used to compare push-out bond strength of different chemical pretreatments. SUCRA (surface area under the cumulative ranking) analysis was performed to rank the pretreatments. After removing duplicates and screening titles and abstracts, 61 studies remained. SUCRA analysis showed that the best bond strength values for self-etch, etch-and-rinse, and self-adhesive cements were ethyl acetate (SUCRA: 99.8%), low concentration NaOCl (SUCRA: 83.4%), and grape seed extract (SUCRA: 97.6%), respectively. According to the SUCRA rankings, ethanol was in a good position for all adhesive strategies (SUCRA: 78.6%). The use of chemical pretreatments in intraradicular dentine of endodontically treated teeth depends on the adhesive and cementation strategy. The pretreatment generally associated with the highest bond strength was ethanol.

Toxicity and effect of whitening toothpastes on enamel surface.

This in vitro study evaluated the biocompatibility and abrasivity of whitening and conventional toothpastes. Samples of conventional (non-whitening) - Edel White Infant (EWI) - and whitening toothpastes - Edel White Whitening (EWW), Edel White CAREFORTE (EWC), Colgate Total 12 Ò Professional (C), and Oral-B Whitening (OB) - were dissolved in culture medium (0.2 g sample weight per mL). Human gingival fibroblasts (hGF) were placed in contact with different dilutions of culture media that had been previously exposed to these toothpastes. Cytotoxicity was then assessed using the methyl tetrazolium test (MTT) and the cell survival rate was determined. Genotoxicity was assessed by the micronucleus test (MNT) and the number of micronuclei was determined before and after exposure to the toothpaste solutions. The enamel surface roughness was evaluated in specimens of bovine teeth (n = 10 per group) before and after 10,000 brushing cycles, using the investigated toothpastes. The results were statistically analyzed using the Mann-Whitney U test and two-way ANOVA (p < 0.05). According to the MTT assay, EWW and OB presented significant cytotoxicity (p < 0.01), but no genotoxic (MNT) effects (p > 0.05). C toothpaste was statistically significantly abrasive to the enamel surface (p < 0.01). The findings of this study may be helpful for individualized selection of commercial toothpastes, as some whitening toothpastes present significant cytotoxicity and conventional toothpaste cause significant surface changes.

Toxicity and effect of whitening toothpastes on enamel surface

Abstract This in vitro study evaluated the biocompatibility and abrasivity of whitening and conventional toothpastes. Samples of conventional (non-whitening) - Edel White Infant (EWI) - and whitening toothpastes - Edel White Whitening (EWW), Edel White CAREFORTE (EWC), Colgate Total 12 Ò Professional (C), and Oral-B Whitening (OB) - were dissolved in culture medium (0.2 g sample weight per mL). Human gingival fibroblasts (hGF) were placed in contact with different dilutions of culture media that had been previously exposed to these toothpastes. Cytotoxicity was then assessed using the methyl tetrazolium test (MTT) and the cell survival rate was determined. Genotoxicity was assessed by the micronucleus test (MNT) and the number of micronuclei was determined before and after exposure to the toothpaste solutions. The enamel surface roughness was evaluated in specimens of bovine teeth (n = 10 per group) before and after 10,000 brushing cycles, using the investigated toothpastes. The results were statistically analyzed using the Mann-Whitney U test and two-way ANOVA (p < 0.05). According to the MTT assay, EWW and OB presented significant cytotoxicity (p < 0.01), but no genotoxic (MNT) effects (p > 0.05). C toothpaste was statistically significantly abrasive to the enamel surface (p < 0.01). The findings of this study may be helpful for individualized selection of commercial toothpastes, as some whitening toothpastes present significant cytotoxicity and conventional toothpaste cause significant surface changes.

Influência das características clínicas e fatores associados às lesões cervicais não-cariosas e tipo de resina composta sobre o sucesso restaurador: observações in silico, in vitro, in vivo e revisão sistemática / Influence of clinical characteristics and factors associated with non-carious cervical lesions and resin composite type on restorative success: in silico, in vitro, in vivo observations and systematic review

O presente trabalho teve como objetivos: (1) analisar, in silico, o efeito de diferentes técnicas restauradoras sobre a concentração de tensão em lesões cervicais não cariosas (LCNCs); (2) avaliar in silico e in vitro a influência do ângulo cavo-superficial sobre a concentração de tensão em LCNCs simuladas; (3) avaliar, in silico e in vitro, a influência da extensão da cavidade e do material restaurador na formação de fendas marginais, e na concentração de tensão em restaurações de resina composta; (4) avaliar, in vivo, a influência da geometria de LCNCs e material restaurador no desempenho clínico das restaurações e (5) analisar, por revisão sistemática e metanálise, a influência dos aspectos relacionados ao dente e cavidade de LCNCs sobre a retenção de restaurações de resina composta. Material e métodos: (1) Um pré-molar superior foi modelado em software CAD, e uma LCNC do tipo cunha foi simulada. Cinco técnicas restauradoras foram reproduzidas com as resinas Filtek™ Z350 XT (N) ou Filtek™ Bulk Fill (BF) e analisadas pelo software Ansys 17.0; (2) Cavidades cilíndricas com mesmo volume (17,67 mm³) foram preparadas em 45 incisivos bovinos. As amostras foram divididas de acordo com o ângulo cavo-superficial, em três grupos: 90º, 120º, 135º, e restauradas com o adesivo Futurabond U e resina GrandioSO. As fendas marginais foram medidas em estereomicroscópio, e análise por elementos finitos (FEA); (3) Cavidades simulando LCNCs com 2 mm (profundidade) C 4 mm (distância cérvico-incisal) foram preparadas em 60 incisivos bovinos em duas dimensões mésio-distais (2,9 mm ou 1,4 mm) e restauradas com N ou BF (n=30). A fenda marginal foi avaliada em estereomicroscópio antes e após da termociclagem, e realizada análise por FEA em cavidades iguais; (4) Cento e quarenta LCNCs foram restauradas em 77 pacientes. As lesões foram previamente classificadas quanto à extensão gengivooclusal (1,5 mm ± 10% e 3 mm ± 10%). Em seguida, as lesões foram alocadas aleatoriamente em quatro grupos (n=35). Após a aplicação de um adesivo autocondicionante, as restaurações foram realizadas com N ou BF. As restaurações foram avaliadas após 7 dias, 6 e 12 meses pelos critérios USPHS modificados; (5) Buscas nas principais bases de dados eletrônicas foram realizadas. Estudos clínicos em pacientes com LCNCs restauradas com resina composta foram incluídos. A retenção da restauração foi o desfecho primário. A qualidade metodológica e risco de viés dos artigos incluídos foi avaliada utilizando a ferramenta Cochrane para ensaios clínicos randomizados e o sistema GRADE. Resultados: (1) A menor concentração de tensão ocorreu no grupo restaurado com resina BF; (2) O ângulo cavo-superficial de 90º promoveu maiores tensões na interface da restauração, com maior fenda marginal; (3) Ocorreu maior concentração de tensão na margem do esmalte, com maior pico de tensão (17,0 MPa) para cavidade pequena restaurada com resina N; (4) A taxa de retenção das restaurações após 12 meses foi de 100% para as LCNCs restauradas com N e de 97% para as LCNCs restauradas com BF; (5) A localização do dente e a presença de facetas de desgaste podem afetar a retenção de resinas compostas em LCNCs(AU)

The aim of the present study was (1) to analyze in silico the effect of different restorative techniques on the stress concentration in non-carious cervical lesions (NCCLs);(2) to evaluate in silico and in vitro the influence of cavosurface margin angle on stress concentration in simulated NCCLs; (3) to evaluate in silico and in vitro the influence of cavity extension and restorative material on the marginal gap formation, and on the stress concentration in resin restoration; (4) to evaluate in vivo the influence of the geometry of NCCLs and restorative material on the clinical performance of restoration and (5) to analyze, through a systematic review and meta-analysis, the influence of tooth- and cavity-related of NCCLs on the retention of resin composite restorations. Materials and Methods: (1) A superior premolar was modeled in CAD software, and a NCCLs of the wedge type was simulated. Five restorative techniques were designed with Filtek™ Z350 XT (N) or Filtek™ Bulk Fill (BF) and analyzed by Ansys 17.0 software; (2) Cylindrical cavities with the same volume (17.67 mm³) were prepared in 45 bovine incisors. The samples were divided according to the cavo-superficial angle in three groups: 90º, 120º, 135º, and restored with Futurabond U adhesive and GrandioSO resin. The marginal gaps were analyzed in stereomicroscope and FEA; (3) Cavities simulating NCCLs with 2 mm (depth) C 4 mm (cervical-incisal distance) were prepared in 60 bovine incisors in two mesiodistal dimensions (2.9 mm or 1.4 mm) and restored with N or BF (n=30. The marginal gap was evaluated using a stereomicroscope before and after thermocycling, and FEA analysis was performed in equal cavities; (4) One hundred and forty NCCLs were restored in 77 patients. The lesions were previously classified for occlusogingival distance (1.5 mm ± 10% and 3 mm ± 10%). Thereafter, the lesions were randomly allocated into four groups (n=35). After applying a self-etching adhesive, the restorations were performed using N or BF. The restorations were evaluated after 7 days, 6 and 12 months using the modified USPHS criteria; (5) Searches in major electronic databases were performed. Clinical studies in patients with NCCLs restored with resin composite were included. Restoration retention was the primary outcome. The quality of the evidence and risk of bias of the included articles was evaluated using the Cochrane tool for randomized clinical trials and the GRADE. Results: (1) The lowest concentration of stress occurred in the group restored with BF resin; (2) The cavosuperficial angle of 90º promoted higher stresses at the interface of the restoration, with a larger marginal gap; (3) Higher stress concentration occurred at the enamel margin, with highest stress peak (17.0 MPa) for small cavity restored with N; (4) The retention rate of the restorations after 12 months was 100% for the NCCLs restored with N and 97% for the NCCLs restored with BF; (5) The tooth location and the presence of wear facets can affect the retention of composite resins in NCCLs(AU)

Clinical performance of whitening on devitalized teeth: a retrospective observational study / Desempenho clínico do clareamento em dentes desvitalizados: estudo observacional retrospectivo

Objective: This retrospective observational study evaluated the clinical performance of intracoronal whitening and correlated the main factors that interfere with its stability and patient satisfaction. Material and Methods: The paper was designed following the STROBE statement. Patients from the Institute of Science and Technology - ICT/UNESP database who underwent nonvital tooth whitening from August 2010 to July 2015 were selected. Data collection was performed by researching the institution records, patients interview, clinical and radiographic examination. Data were analyzed using MannWhitney test and Spearman's correlation (p < 0.05). Results: The initial search on 1275 records resulted in 43 patients, of whom 18 were selected according to eligibility criteria. There was positive correlation only between the degree of patient's satisfaction and the perception of color difference after whitening treatment (p < 0.05). Color relapse was observed in all conditions, independently of the period of followup (p > 0.05). There was no case of external cervical root resorption. Conclusion: Color changes after whitening influenced patient's satisfaction. There was no correlation among the color relapse and height of gutta-percha, return interval or cause of darkening (AU)

Objetivo: Este estudo observacional retrospectivo avaliou o desempenho clínico do clareamento interno e correlacionou os principais fatores que interferem em sua estabilidade e satisfação do paciente. Material e Métodos: O artigo foi elaborado seguindo o STROBE. Pacientes do banco de dados do Instituto de Ciência e Tecnologia ­ ICT/UNESP que foram submetidos ao clareamento dental em dentes desvitalizados entre agosto de 2010 e julho de 2015 foram selecionados. A coleta de dados foi realizada por meio de pesquisa em prontuários da instituição, entrevista com os pacientes, exames clínico e radiográfico. Os dados foram analisados usando o teste de Mann-Whitney e correlação de Spearman (p < 0,05). Resultados: A pesquisa inicial em 1275 registros resultou em 43 pacientes, dos quais 18 foram selecionados de acordo com os critérios de elegibilidade. Houve correlação positiva apenas entre o grau de satisfação do paciente e a percepção da diferença de cor após o tratamento clareador (p < 0,05). A recidiva da cor foi observada em todas as condições, independentemente do tempo de acompanhamento (p > 0,05). Não houve nenhum caso de reabsorção cervical externa. Conclusão: As mudanças de cor após o clareamento influenciaram a satisfação do paciente. Não houve correlação entre a recidiva da cor e a altura do guta-percha, o intervalo de retorno ou a causa do escurecimento. (AU)

Influence of cavosurface angle on the stress concentration and gaps formation in class V resin composite restorations.

The study aimed to evaluate the influence of cavosurface angle on stress concentration and gap formation in class V restorations. Cylindrical cavities 3 mm in diameter were prepared in forty-five bovine incisors, changing only the angle of the bur in relation to the flat surface of the tooth. The cavities maintained the same volume (17.67 mm³). The samples were divided according to the cavosurface angle, into three groups (n = 15): 90°, 120°, 135°. After adhesive application (Futurabond U, VOCO), the cavity was filled with bulk placement of a resin composite (GrandioSO, VOCO). The teeth were analyzed with stereomicroscopy. Data of marginal gap formation were statistically analyzed with a one-way analysis of variance (ANOVA) followed by Tukey tests (significance level: α = 0.05). Finite element analysis (FEA) was used to study residual stress in these geometries and to correlate those stresses with experimentally measured gap formation. The elastic modulus and polymerization shrinkage were determined for FEA. Residual shrinkage stresses were expressed in maximum principal stress (MPS). There was a significant difference in the gap formation among the groups (p = 0.001). A significantly lower marginal gap formation was found for 120° and 135° angles, with no significant difference between them. The cavosurface angle at 90° caused substantially higher stresses, in the restoration interface, with greater marginal gap. For the 120° and 135° angles, the stress concentrations were smaller and were located in the dental structure. The cavosurface angle influenced the marginal gap formation and stress concentration.

Influence of interim cements on the optical properties of interim restorations.

STATEMENT OF PROBLEM: Even if the appropriate resin shade is selected for an interim restoration, how the optical characteristics of the interim cement affect the esthetics of the interim restoration is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the effects of interim cements on the optical properties of interim restorations. MATERIAL AND METHODS: Twenty dentin disks (6×1 mm) were obtained from the labial surface of bovine incisors. Disks of acrylic and bis-acrylic resins (n=20) with the same dimensions were prepared and cemented over the dentin using the following cements: Bifix Temp (resin-based; VOCO), ClearTemp LC (resin-based; Ultradent Products, Inc), Provicol (VOCO), TempCem NE (Coltène). The same dentin and resin disks were used for all cements. After cementation, the color difference (ΔE00), translucency parameter (TP), and fluorescence of the dentin/cement/resin combinations were compared with each other and with a control group (C), in which a transparent liquid (polyethylene glycol 400; LabSynth) was applied. Color and translucency were evaluated with a spectrophotometer (CM-2600; Konica Minolta) and fluorescence with a spectrofluorophotometer (RF-5301PC; Shimadzu). ΔE00 and TP data were analyzed using 2-way ANOVA. For fluorescence, 1-way ANOVA was used. The Tukey test was used for multiple comparisons (α=.05). RESULTS: ΔE00 values were significantly influenced by the interim material (P<.001) and the interim cement (P<.001). Bifix Temp showed the lowest significant ΔE00 values (P<.001). The highest ΔE00 values were observed for TempCem NE. No differences were observed between the interim resins with respect to TP (P=.318). The lowest translucency values were measured for TempCem NE, followed by Provicol, ClearTemp LC, Bifix Temp, and the control group (P<.001), with no significant differences among the interim resin-based cements. Among the cements, Bifix Temp and TempCem NE yielded fluorescence similar to that of the natural tooth for both interim resins. A similar result was found for bis-acrylic resin combined with Provicol. CONCLUSIONS: Cementation with interim resin-based cements resulted in better esthetics. However, the high fluorescence of the ClearTemp LC may reduce the esthetics of interim restorations in environments with predominantly UV light.

Polymerization shrinkage stresses in different restorative techniques for non-carious cervical lesions.

OBJECTIVE: This study evaluated the effect of different restorative techniques for non-carious cervical lesions (NCCL) on polymerization shrinkage stress of resins using three-dimensional (3D) finite element analysis (FEA). METHODS: 3D-models of a maxillary premolar with a NCCL restored with different filling techniques (bulk filling and incremental) were generated to be compared by nonlinear FEA. The bulk filling technique was used for groups B (NCCL restored with Filtek™ Bulk Fill) and C (Filtek™ Z350 XT). The incremental technique was subdivided according to mode of application: P (2 parallel increments of the Filtek™ Z350 XT), OI (2 oblique increments of the Filtek™ Z350 XT, with incisal first), OIV (2 oblique increments of the Filtek™ Z350 XT, with incisal first and increments with the same volume), OG (2 oblique increments of the Filtek™ Z350 XT, with gingival first) and OGV (2 oblique increments of the Filtek™ Z350 XT, with gingival first and increments with the same volume), resulting in 7 models. All materials were considered isotropic, elastic and linear. The results were expressed in maximum principal stress (MPS). RESULTS: The tension stress distribution was influenced by the restorative technique. The lowest stress concentration occurred in group B followed by OG, OGV, OI, OIV, P and C; the incisal interface was more affected than the gingival. CONCLUSION: The restoration of NCCLs with bulk fill composite resulted in lower shrinkage stress in the gingival and incisal areas, followed by incremental techniques with the initial increment placed on the gingival wall. CLINICAL SIGNIFICANCE: The non-carious cervical lesions (NCCLs) restored with bulk fill composite have a more favorable biomechanical behavior.

Influence of solutions with pigmentation potential on tooth color after bleaching using 22% carbamide peroxide / Influência de soluções com potencial de pigmentação na cor dos dentes após clareamento com peróxido de carbamida a 22%

The color stability achieved by dental bleaching can be affected by exposure to staining agents present in foods. However, there is scarce research regarding tooth staining during dental bleaching. This study investigated the effect of pigments on the color stability of dental elements during dental bleaching. Blocks obtained from bovine incisors were divided into seven groups (n = 10) in accordance with the staining pigments (distilled water ­ control; coffee, cola, tea, red wine, chocolate milk and soya sauce (Shoyu). The color was evaluated with a spectrophotometer (Minolta CR-321, Japan) before and after dental bleaching (1st and 14th days), employing the (CIE) L*a*b* system. The dental bleaching procedure was performed using 22% carbamide peroxide gel applied to the sample surface for a period of 1 hour each day, for 14 days. After dental bleaching, the teeth were exposed to 20 ml of staining solution for 5 minutes, at 37ºC and 100 rpm for different periods. During the experiment, the samples were stored in distilled water. Data was analyzed using ANOVA followed by Tukey tests, with a significance level of 5%. Significant differences for E* values (p<0.05) were observed between the groups. The Shoyu group presented a decrease in luminosity (negative value of L*). It could be concluded that all solutions contained pigments that promoted staining on the surface. However, bleached enamel was susceptible to staining with soya sauce (Shoyu), while other substances did not interfere with the dental bleaching.

A estabilidade de cor conseguida por meio do clareamento dental pode ser afetada pela exposição à agentes pigmentantes presentes nos alimentos. Contudo, há uma escassa investigação sobre o manchamento dos dentes durante o clareamento dental. Este estudo investigou o efeito de agentes pigmentantes sobre a estabilidade da cor dos dentes durante o clareamento dental. Os blocos obtidos a partir de incisivos bovinos foram divididos em sete grupos (n = 10) de acordo com os agentes pigmentantes (água destilada - controle - café, cola, chá, vinho tinto, leite achocolatado e molho de soja - shoyu. A cor foi avaliada com um espectrofotômetro (Minolta CR-321, Japão) antes e após o clareamento (1º e 14º dias), utilizando o sistema (CIE) L*a*b*. O procedimento de clareamento dental foi realizado usando gel de peróxido de carbamida a 22% aplicado à superfície da amostra por um período de 1 hora por dia, durante 14 dias. Após o clareamento, os dentes foram expostos a 20 ml da solução pigmentante por 5 minutos, 37ºC e 100 rpm em diferentes períodos. Durante o experimento, as amostras foram armazenadas em água destilada. Os dados foram analisados por meio do teste ANOVA, seguido do Tukey, com nível de significância de 5%. Foram observadas diferenças significativas para os valores de E* (p <0,05) entre os grupos. O grupo Shoyu apresentou uma diminuição na luminosidade (valor negativo de L*). Pode-se concluir que todas as soluções que continham pigmentos promoveram manchamento superficial. No entanto, o esmalte clareado foi susceptível apenas ao manchamento com molho de soja (Shoyu), enquanto outras substâncias não interferiram no tratamento de clareamento dental.

Effect of temporary cements on the bond strength of a resin cement to a pre-hybridized dentin / Influência de cimentos temporários na resistência de união de um cimento resinoso sobre a dentina pré-hibridizada

This study assessed the bond strength of a resin cement when Immediate Sealed Dentin (ISD) was contaminated by different temporary cements applying a microshear test. Forty-eight fragments of third molar crowns were mounted in acrylic resin and worn until the dentin was exposed. The substrates were sealed with a 3-step conventional adhesive system and divided into four groups (n=12): Control (without temporary cement) and three groups that used different temporary cements - Provy, RelyX Temp NE, and Provitemp. The temporary cements were removed after 7 days of storage. Resin cement RelyX ARC was applied to the contaminated substrates. Microshear bond strength was evaluated using a universal testing machine (0.5 mm/min). Data was analyzed with ANOVA and a Dunnett post-hoc test (p<0.05). Additionally, three samples from each group were prepared for scanning electron microscope analysis. Means and standard deviations of microshear bond strength (MPa) were 17.96±1.65, 16.70±1.43, 20.43±1.30 and 33.75±4.72 for Control, Provy, RelyX Temp, and Provitemp, respectively. Statistically significant difference was observed between the Control and Provitemp samples (p=0.0002). Adhesive failures were dominant (50%), followed by cohesive failures with cement (26%), and cohesive failures with dentin (24%). Residues of Provy and Provitemp were observed on the sealed dentin. Provitemp temporary cement sealing increased the microshear bond strength of the resin cement on dentin treated with IDS.

Este estudo investigou a influência de cimentos temporários na resistência de união de um cimento resinoso em dentina selada imediatamente. Quarenta e oito fragmentos obtidos das coroas de terceiros molares foram incluídos em tubos de PVC com resina acrílica e desgastados até exposição da dentina. Os substratos foram tratados com adesivo convencional de três passos e divididos em quatro grupos: Controle (sem cimento temporário) e três grupos usando diferentes cimentos temporários ­ Provy, RelyX Temp NE e Provitemp. Após sete dias, os cimentos foram removidos e o cimento RelyX ARC aplicado sobre o substrato contaminado. A resistência de união foi avaliada em uma máquina de ensaio universal (0,5 mm/min). Os dados foram analisados pelos testes estatísticos ANOVA e Dunnet (p<0,05). Três amostras de cada grupo foram preparadas para análise em micróscopio eletrônico de varredura. Os valores médios e desvio padrão da resistência de união foram 17,96 ±1,65, 16,70 ±1,43, 20,43±1,30 e 33,75 ±4,72 para Controle, Provy, RelyX Temp e Provitemp, respectivamente. Diferença significativa foi observada entre os grupos Controle e Provitemp (p=0,0002). Com relação ao padrão de fratura, a maioria das falhas foram adesivas (50%), seguida por coesiva em cimento (26%) e coesiva em dentina (24%). Resíduos dos cimentos Provy e Provitemp foram observados na dentina selada. Cimento temporário Provitemp aumentou a resistência de união por microcisalhamento do cimento resinoso a dentina com IDS.

Effect of laser photobiomodulation on the periodontal repair process of replanted teeth.

BACKGROUND/AIM: Tooth replantation is the optimal treatment in cases of avulsion. However, its success is limited due to the occurrence of external root resorption. The aim of this study was to assess the effect of laser photobiomodulation (LPBM) at λ808 nm and λ660 nm and of storage media on the periodontal repair process of replanted teeth in rats. MATERIAL AND METHODS: Sixty maxillary right incisors were extracted from sixty Wistar rats and randomly assigned to six groups (n = 10). Groups consisted of 10 teeth stored in paper napkins (PN), whole milk (WM), and soy milk (SM), for 45 min; and PNL, WML and SML, in which teeth were stored in the same storage media, but the root surface and the alveolus were treated with LPBM at λ808 nm before replantation, and the buccal and palatal mucosa of the alveolus were treated with LPBM at λ660 nm after replantation. Five rats from each group were euthanized after 15 or 30 days. The right hemimaxilla including the replanted incisor was removed and processed for histomorphometric analysis to assess root resorption areas, replacement root resorption, perimeter with ankylosis and periodontal repair, and areas of type I and III collagen deposition, using the ImageJ 1.50b software. Data were analyzed statistically by anova followed by Tukey's multiple comparison test (α = 5%). RESULTS: WM and SM showed smaller root resorption areas and higher collagen deposition in both experimental periods, and SM showed the largest perimeter of periodontal repair. LPBM reduced the occurrence of root resorption only in the PNL group, both at 15 and 30 days, and increased the perimeter of periodontal repair in all groups at 30 days. There was higher collagen deposition in the irradiated groups regardless of the experimental period. CONCLUSIONS: The LPBM protocol at λ808 nm and λ660 nm as well as whole milk and soy milk favored the periodontal repair process of replanted teeth in rats.

Tooth color change caused by photosensitizers after photodynamic therapy: An in vitro study.

This study aimed to perform an in vitro evaluation of the effect of photosensitizers used in photodynamic therapy (PDT) on tooth color change when used in combination with conventional endodontic treatment. Forty extracted human mandibular premolars were accessed and underwent root canal therapy and PDT. Photosensitizers were used in accordance with the experimental groups: MB (n=10) - PDT with Methylene Blue at 0.01%; TB (n=10) - PDT with Toluidine Blue at 0.01%; MG (n=10) - PDT with Malachite Green at 0.01%, at the concentration of 0.1mg/mL; and PC (n=10) - positive control, PDT with Endo-PTC cream stained with Methylene Blue at 25%. The samples were irradiated with 660-nm diode laser by means of a 330-µm-diameter optical fiber cable at a power density of 40mW for 120s. After light curing, the photosensitizers were removed from the specimens with 10mL sodium hypochlorite at 1%. A reflectance spectrometer was used for evaluation of color prior to and 60days after the experimental procedure based on the CIE L*a*b* system. According to ANOVA test, there were statistically significant differences between the experimental groups (p=0.003). Tukey's test showed a significant difference between PC and TB (p=0.008), as well as between MG and TB (p=0.009). However, there was no statistically significant difference between PC, MG (p=0.957) and MB (p=0.103). It was concluded that the use of PDT as an adjuvant to root canal therapy, using different photosensitizers, led to color change in tooth structure.

Effect of thickness on fluorescence of resin composites and dental substrates / Efeito da espessura sobre a fluorescência de resinas compostas e substratos dentais

Objective: This study evaluated the effect of thickness on fluorescence of resin composites and tooth substrates (enamel and dentin). Material and methods: Ninety bovine incisors were used, resulting in 45 dentin and 45 enamel disks (6 mm diameter and 0.5, 1, or 1.5 mm in thickness). Ninety discs of Charisma, Filtek Z350 and IPS Empress Direct (for enamel and dentin) resins at same dimensions were built. Fluorescence measurements were performed using a fluorescence spectrophotometer (RF-5301PC, Shimadzu Corp) with excitation at 365 nm. Data were submitted to 2-way ANOVA and Tukey’s post hoc tests (α = 0.05). Results: The 2-way ANOVA revealed statistically significant differences for all factors, as well as the interaction between them (p <0.05). Dentin specimens (1.5 mm) showed highest fluorescence (128.33 A.U.), while Filtek Z350 (dentin - 1.0 mm) showed the lowest fluorescence (29.84 A.U.). Thickness influenced fluorescence values of enamel substrate. Conclusion: The thickness influenced fluorescence of enamel and all resin composite assessed showed fluorescence lower than natural dentin.

Objetivo: Este estudo avaliou o efeito da espessura de resinas compostas e substratos dentais (esmalte e dentina) sobre a fluorescência. Materiais e Métodos: Noventa incisivos bovinos foram utilizados, resultando em 45 discos de dentina e 45 discos de esmalte (6 mm de diâmetro e 0,5, 1 ou 1,5 mm mm de espessura). Noventa discos das resinas compostas Charisma, Filtek Z350 e IPS Empress Direct (para esmalte e dentina) foram confeccionados com a mesma dimensão. A fluorescência foi analisada por meio de espectrofluorímetro (RF-5301PC, Shimadzu Corp) com excitação de 365nm. Os dados foram submetidos ao teste ANOVA dois fatores e Teste de Tukey (α = 0,05). Resultados: O teste ANOVA dois fatores revelou diferenças significativas para todos os fatores, bem como para interação entre eles (p < 0,05). As amostras de dentina (1,5 mm) apresentaram alta fluorescência (128,33 A.U.), enquanto a resina composta Filtek Z350 (dentina - 1,0 mm) apresentou menor fluorescência (29,84 A.U.). A espessura influenciou os valores de fluorescência para o substrato esmalte. Conclusão: A espessura influenciou na fluorescência do esmalte e todas as resinas compostas avaliadas apresentaram uma fluorescência menor do que a dentina natural.

Efeito opacificador de resinas compostas em dentes anteriores: relato de caso / Opacifying effects of composites in anterior teeth: a case report

O restabelecimento da harmonia estética dos dentes anteriores tem sido um grande desafio para a odontologia restauradora. Estratégias reabilitadoras incluem o uso de compósitos com ênfase no mínimo desgaste, máxima conservação e reprodução das características da estrutura dental no que se diz respeito à devolução da cor, forma e função ao paciente. Portanto, este relato de caso descreve o protocolo restaurador de incisivos superiores centrais escurecidos, por meio de protocolo restaurador simples, com ênfase na estratificação de cor das resinas compostas, incluindo toda a sequência clínica com o intuito de reproduzir e devolver características naturais da estrutura dental com proporções, forma e cor satisfatórias...

The restoration of the aesthetic harmony of anterior teeth is a great challenge for Restorative Dentistry. Rehabilitation strategies include the use of composites with emphasis on minimal wear, maximum conservation and reproduction of the characteristics of the tooth structure such as color matching, form and function to the patient. Therefore, this case report describes the restorative protocol for darkened maxillary central incisors, through the use of a simple restorative protocol, with emphasis on color stratification of composites, including all clinical sequence towards the reproduction and restablishment of the natural characteristics of the tooth structure with satisfactory proportions, shape and color...

Efeito da intensidade de fontes de luz e barreiras de cerâmica na microdureza de cimento resinoso dual / Effect of intensity of light sources and barriers in ceramic hardness of dual-cured cement

Introdução: O cimento resinoso dual é o principal material para cimentação de cerâmicas. Contudo, fatores, como fonte de luz, podem influenciar no desempenho do cimento. Objetivo: Avaliar a influência de duas fontes de luz de diferentes intensidades sobre a microdureza de um cimento resinoso quando fotoativado sob diferentes cerâmicas. Material e método: Foram fotoativados 40 espécimes de cimento resinoso dual (10 mm × 1,0 mm) por meio de duas fontes de luz LED, com intensidades de 1.000 mW/cm² e 800 mW/cm² durante 40 segundos, sob cerâmicas (15 mm × 2 mm) à base de zircônia, espinélio MgAl2O4 e dissilicato de lítio. No grupo controle, foi utilizada uma placa de vidro de mesma dimensão. As amostras tiveram a superfície regularizada com lixa d`água (600 e 1200). Após armazenagem a seco no escuro (24 h), foram realizadas as medidas de microdureza Vickers (HMV Shimadzu - 50g/10 segundos). Os dados foram submetidos à Anova fatorial e ao teste de Tukey com nível de significância de 5%. Resultado: O cimento polimerizado apresentou valor médio de microdureza e desvio padrão para o grupo controle de 43,9±1,5 e 43,4±1,3, para as intensidades de 1.000 mW/cm2 e 800 mW/cm2, respectivamente. O menor valor de microdureza do cimento foi observado para a cerâmica à base de espinélio MgAl2O4, polimerizado a 800 mW/cm², com valor de 34,3±3,3.