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Introducción: Las resinas de incremento único permiten una fotoactivación de 4 a 5 mm de profundidad, reduciendo el tiempo clínico de aplicación. No obstante, se deben considerar factores como la contracción que puede afectar el sellado marginal de la restauración. Objetivo: Evaluar el efecto de tres fuentes de polimerización sobre el sellado marginal de restauraciones Clase II, realizadas con tres sistemas de resina de incremento único. Métodos: Se realizó un estudio experimental in vitro. El cálculo de la cantidad de unidades de estudio se realizó con el software EPIDAT, para lo cual se tomaron las medias de dos estudios previos. Se realizaron nueve subgrupos según el material de restauración y la fuente de polimerización. En cada diente se confeccionaron dos restauraciones Clase II, que fueron realizadas según las instrucciones del fabricante. Los dientes fueron sometidos a inmersión pasiva en azul de metileno al 1 por ciento por 24 h. Los dientes fueron seccionados mesiodistalmente. Se realizaron fotografías con una cámara Canon y un lente macro 100 mm. La filtración marginal fue medida según una escala del 0 al 4. Los datos fueron analizados con las pruebas de Kruskal-Wallis para la comparación de los grupos. Se estableció un nivel de significancia ajustado al 5 por ciento. Resultados: La resina con menor nivel de filtración fue Filtek Bulkfill, con un 53,3 por ciento correspondiente a la escala 0, mientras que la resina con una mayor filtración fue Tetric N-Ceram Bulk Fill con un 76,7 por ciento (escala 4), similar a Sonicfill (70,0 por ciento). Conclusiones: Las diferentes fuentes de polimerización no influenciaron el nivel de filtración entre los tres sistemas de resinas de incremento único. Filtek Bulkfill presentó un mejor sellado marginal al compararlo con SonicFill y Tetric N-Ceram Bulk Fill(AU)

Introduction: Single-increment resins allow a photoactivation of 4 to 5 mm deep, reducing the clinical time of application. However, factors such as shrinkage that may affect the marginal sealing of the restoration should be considered. Objective: Evaluate the effect of three polymerization sources on the marginal sealing of Class II restorations, carried out with three single-increment resin systems. Methods: An in vitro experimental study was conducted. The calculation of the number of study units was carried out with the EPIDAT software, for which the means of two previous studies were taken. Nine subgroups were made according to the restoration material and the polymerization source. Two Class II restorations were made on each tooth, which were carried out according to the manufacturer's instructions. The teeth were subjected to passive immersion in 1 percent methylene blue for 24h. The teeth were sectioned mesiodistally. Photographs were taken with a Canon camera and a 100mm macro lens. Marginal filtration was measured on a scale of 0 to 4. Data were analyzed with Kruskal-Wallis tests for group comparison. A significance level adjusted to 5 percent was established. Results: The resin with the lowest filtration level was Filtek Bulkfill, with 53.3 percent corresponding to scale 0, while the resin with the highest filtration was Tetric N-Ceram Bulk Fill with 76.7 percent (scale 4), similar to Sonicfill (70.0 percent). Conclusions: The different polymerization sources did not influence the level of filtration between the three single-increment resin systems. Filtek Bulkfill presented a better marginal seal when compared to SonicFill and Tetric N-Ceram Bulk Fill(AU)

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Allergic reactions are host immune responses to endogenous or exogenous antigens, which can result in local and systemic problems. Among the main allergens are the dental materials used in orthodontics, which faces some challenges with regard to biocompatibility with oral tissues.This study aimed to analyze in the literature which materials used in orthodontics are related to the appearance of oral and perioral allergic reactions, as well as to investigate the most prevalen t manifestations.An integrative review was carried out with articles published between 2010 and 2020 on the PubMed, Embase, and ScienceDirect on-line database. For this, MeSH descriptors and synonyms were used following two semantic fields: "Hypersensitivity" in association with "Orthodontic Appliances", the selection of studies counted with the stages of identifica tion, screening, eligibility and inclusion. Randomized clinical trials, cross-sectional or cohort clinical trials; Patients with alle rgic reactions affecting the oral or perioral region due to contact with orthodontic material, were included in the review.From a to tal of 549 articles only 04 were selected for the study. In accordance with what has been analyzed in the evidence of these studies, periodontal changes such as gingival inflammation as well as erythema, edema, papules and blisters were the main reactions described. Furthermore, in all articles there was an association with nickel and in only one with chromium. It is possible to i nfer that inflammatory lesions are frequent manifestations on the use of nickel in orthodontic patients.

Las reacciones alérgicas son respuestas inmunes del huésped a antígenos endógenos o exógenos, los cuales pueden provocar problemas locales y sistémicos. Entre los principales alérgenos se encuentran los materiales dentales utilizados en la ortodoncia, la cual se enfrenta a algunos desafíos respecto a la biocompatibilidad de los tejidos orales. Este estudio tuvo como objetivo analizar en la literatura que materiales utilizados en ortodoncia están relacionados con la aparición de reacciones alérgicas orales y periorales, así como investigar las manifestaciones más prevalentes. Se llevó a cabo una revisión con artículos publicados entre 2010 y 2020 en las bases de datos PubMed, Embase y ScienceDirect. Para ello, se utilizaron descriptores y sinónimos de MeSH siguiendo dos campos semánticos: "Hipersensibilidad" en asociación con "Aparatos de Ortodoncia", la selección de estudios contó con las etapas de identificación, cribado, elegibilidad e inclusión. Ensayos clínicos aleatorizados, ensayos clínicos transversales o de cohortes; en la revisión se incluyeron pacientes con reacciones alérgicas que afectaron a la regiones oral o perioral debido al contacto con material de ortodoncia. De un total de 549 artículos sólo cuatro fueron seleccionados para el estudio. De acuerdo con lo que se analizó en la evidencia, las principales reacciones descritas fueron cambios periodontales, como inflamación gingival, eritema, edema, pápulas y ampollas. Además, en todos los artículos hubo una asociación con níquel y solamente en uno con cromo. Es posible inferir que las lesiones inflamatorias son manifestaciones frecuentes sobre el uso de níquel en pacientes de ortodoncia.

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Abstract: The purpose of this study was to describe the synthesis, characterization, and functionalization of b-NaYF4:30%Yb/0.5%Tm upconverting nanocrystals for use as nanofillers in a dental adhesive and microscopically evaluate the interface between the particles and a commercial adhesive. The upconverting nanoparticles were synthesized and purified by thermal decomposition, and their chemical composition determined by energy dispersive X-Ray spectroscopy. The crystalline structure was characterized using X-Ray diffraction and morphology and size were observed with scanning and transmission electron microscopy. Upconverting emission was evaluated by spectrophotometry irradiating the particles with a 975 nm diode laser. Particles were functionalized with polyacrylic acid and the success was confirmed by measurement of Zeta Potential and transmission electron microscopy. The results of X-ray diffraction found a pure hexagonal phase crystalline pattern. Scanning electron microscopy showed uniform dispersion of hexagonal-shaped particles of approximately 150 nm. Upconversion emission was observed in 344 nm, 361 nm, 450 nm, 474nm, 646 nm, 803 nm. Functionalization success was confirmed by formation of a stable aqueous colloid with a Zeta potential of −29.5mV and the absence of voids in the particle-adhesive interface on the transmission electron microscopy images. The reported synthesis and functionalization process produced upconverting nanoparticles emitting photons within the blue spectral region (450 nm and 474 nm).

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ABSTRACT Objective: To evaluate the remineralizing potential of a hydrocolloid-based, controlled fluoride-releasing system added to dentifrice formulas. Material and Methods: Sixty-five human enamel blocks were prepared and the surface microhardness (SH0) values were determined. The artificial caries lesions were induced and the demineralization surface microhardness (SH1) was evaluated. The blocks were randomly allocated into five groups (n = 13): (1) 100-TGF (100% NaF with Tara gum added); (2) 50-TGF (50% free NaF + 50% NaF with Tara gum added); (3) 100% TG (100% Tara gum without fluoride); (4) 100% NaF (positive control); and (5) placebo (without Tara gum and NaF). The blocks were submitted to 7 days pH cycling and treated with dentifrice slurries twice a day. Finally, surface hardness (SH2) was assessed and the percentage of surface hardness recovery (%SMHR) was calculated. Analysis of variance (ANOVA) followed by Bonferroni test was used for statistical analysis. Results: A positive %SMHR was found in the 100% NaF (5.07) and 50-TGF (0.64) groups, while the 100-TGF (-1.38), 100% TG (-3.88) and placebo (-0.52) did not undergo remineralization. Statistically significant differences were observed between 100% NaF and all the groups except for 50-TGF (p<0.05). Conclusion: The presence of hydrocolloid (Tara gum) promoted minimal remineralization when associated with NaF. In the applied model, Tara gum may have compromised remineralization, preventing free fluoride from acting effectively in the carious lesion.

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Abstract Objective: To evaluate in vitro the antimicrobial effect of Listerine-green tea mouthwash on Streptococcus mutans (SM) in comparison with 0.12% Chlorhexidine (CHX) and Listerine-Zero. Material and Methods: The sensitivity and growth inhibition of SM bacterial species were evaluated and compared between Listerine-green tea, 0.12% CHX and Listerine-Zero mouthwashes. Sixty plates containing SM colonies were prepared in three groups (n=20), and growth inhibition zones were measured using the disk diffusion agar test in mm. Data were analyzed with SPSS 21. One-way ANOVA was used to compare the efficacy of the three mouthwashes tested. Post hoc Tukey tests were used for two-by-two comparisons. Statistical significance was defined at P<0.05. Results: Analysis of data showed significant differences between the three groups (p<0.001); 0.12% CHX was the most effective mouthwash, and Listerine-Zero exhibited the least effect on the growth inhibition of SM (p<0.004). Conclusion: All three mouthwashes were significantly effective in inhibiting the growth of SM. The effect of Listerine-green tea mouthwash was higher than that of Listerine-Zero and less than that of 0.12% CHX.

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Abstract This study evaluated the influence of activation modes, on Diametral Tensile Strength (DTS) of dual cured resin cements subjected to a Mechanical Fatigue test (MF). Four dual-cured resin cements (RelyX UNICEM [U], RelyX ARC [A], ENFORCE [E] and Nexus 2 [N]) were activated by three different curing modes as follows: Self-Curing (SC), Dual Cure activation with photoactivation executed directly (DC) and Dual Cure activation with Photoactivation Through Porcelain (DCTP). After 24 hours, half of the sample was subjected to 30.000 fatigue cycles at 1 Hz frequency and 12 N load. Then, all specimens were subjected to DTS test in Instron Universal Testing Machine and data were analyzed by three-way ANOVA and Tukey's Test (5%). The results of DTS test means (MPa) and standard deviation, for each cement factor activated by SC, DC and DCTP was respectively: U (28.12 ± 5.29; 37.44 ± 6.49 and 40.10 ± 4.39), A (49.68 ± 8.42; 55.12 ± 5.16 and 63.43 ± 6.92), E (49.12 ± 3.89; 56.42 ± 8.88 and 56.96 ± 6.45) and N (61.89 ± 11.21; 59.26 ± 9.47 and 62.56 ± 10.93). Turkey's test indicated that DC is related to the highest DTS values; Nexus 2 DTS remained the same independently of activation mode and that the Porcelain disk interposition enhanced DTS only for RelyX ARC the ANOVA statistical test indicated that MF didn't alter the DTS values for all experimental groups. MF results clinical implication is that all cements tested exhibited, in an immediate loading, good cross linked bonds quality.

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AIM AND OBJECTIVES: This study assessed, through finite element analysis, the biomechanical behavior of an implant system using the All-on-Four® technique with nickel-chromium (M1) and polyether ether ketone (PEEK) bars (M2). MATERIALS AND METHODS: Implants and components were represented in three-dimensional (3D) geometric models and submitted to three types of load: axial, oblique, and load on all teeth. The 3D models were exported to a computer-aided design-like software such as Solidworks 2016 (Dassault Systemes, Solidworks Corps, USA) for editing and Nonuniform Rational Basis Splines parametrization. RESULTS: Data were analyzed according to system's areas of action: peri-implant bone, implant, intermediates, intermediates' screws, prostheses' screws, and bars. Largest peak stress was shown in M2. CONCLUSION: PEEK is a promising material for use in dentistry; however, further studies are necessary to evaluate its performance.

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PURPOSE: The present study aimed to evaluate which of the following imaging methods best assessed misfit at the tooth-restoration interface: (1) bitewing radiographs, both conventional and digital, performed using a photostimulable phosphor plate (PSP) and a charge-coupled device (CCD) system; (2) panoramic radiographs, both conventional and digital; and (3) cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Forty healthy human molars with class I cavities were selected and divided into 4 groups according to the restoration that was applied: composite resin, composite resin with liner material to simulate misfit, dental amalgam, and dental amalgam with liner material to simulate misfit. Radiography and tomography were performed using the various imaging methods, and the resulting images were analyzed by 2 calibrated radiologists. The true presence or absence of misfit corresponding to an area of radiolucency in regions subjacent to the esthetic and metal restorations was validated with microscopy. The data were analyzed using a receiver operating characteristic (ROC) curve, and the scores were compared using the Cohen kappa coefficient. RESULTS: For bitewing images, the digital systems (CCD and PSP) showed a higher area under the ROC curve (AUROC) for the evaluation of resin restorations, while the conventional images exhibited a larger AUROC for the evaluation of amalgam restorations. Conventional and digital panoramic radiographs did not yield good results for the evaluation of resin and amalgam restorations (P<.05). CBCT images exhibited good results for resin restorations (P>.05), but showed no discriminatory ability for amalgam restorations (P<.05). CONCLUSION: Bitewing radiographs (conventional or digital) should be the method of choice when assessing dental restoration misfit.

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Abstract To evaluate the effect of different surface treatments on the marginal misfit and retentive strength between Y-TZP crowns and an epoxy resin. Forty (40) epoxy resin (G10) abutments (height: 5mm, conicity: 60, finish line: large chamfer) with equal dimensions were milled and included in polyurethane to simulate the periodontal ligament. Next, 40 Y-TZP crowns (thickness: 1mm) were milled (Cerec in Lab) and randomly divided into four groups (n=10) according to the surface treatment: GS(glaze spray), GP(glaze powder/liquid), P(zirconia primer) and RS(tribochemical silica coating). The conditioned surfaces were cemented with dual self-adhesive cement, light cured and submitted to thermomechanical cycling (2x106, 100N, 4Hz, 5°/55°C). Marginal misfit was analyzed by a stereomicroscope and SEM. Retentive strength test was performed (1mm/min) until crown debonding. Glaze layer thickness was also performed to GS and GP groups. Marginal misfit data were analyzed by Kruskal Wallis and Dunn tests; one-way ANOVA and Tukey (5%) analyzed the tensile strength data. The marginal misfit of the GS (48.6±19.9μm) and GP (65.4±42.5μm) were statistically lower than the RS (96±62.9μm) and P (156±113.3μm) (p=0.001). The retentive strength of the GP (470.5±104.1N) and GS (416.8±170.2N) were similar to the P (342.1±109.7N), but statistically higher than those of the RS (208.9±110N). The GS and GP glaze layer was 11.64μm and 9.73μm respectively. Thus, glaze application promoted lower marginal discrepancy and higher retentive strength values than conventional techniques.

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A movimentação dentária é obtida através de recursos capazes de gerar forças e o ortodontista dispõe de uma série de dispositivos mecânicos responsáveis por realizar essa movimentação, incluindo os elásticos em cadeia, que além de serem de fácil aplicação, são também bem tolerados pela maioria dos pacientes. Porém, apesar dos avanços obtidos no desenvolvimento destes materiais, ainda existem dúvidas em relação a influência de diversos fatores que podem afetar a liberação de forças destes. O objetivo deste trabalho é avaliar a redução dos valores das forças geradas por elásticos ortodônticos em cadeia em relação a intensidade de estiramento, tempo e configuração. Foram utilizados 432 segmentos de cadeias elásticas, divididos em 3 grupos de acordo com as configurações curta, média e longa. Os segmentos de cadeia foram distendidos em 25%, 50%, 75% e 100% do comprimento original e mantidos estirados em placas de acrílicos confeccionadas especialmente para esse fim, em água destilada, a temperatura constante de 37°C durante os períodos de 24 horas, 1, 2, 3 e 4 semanas. Os dados foram avaliados através do teste de Análise de Variância (ANOVA) seguido do teste de Tukey. Todos os fatores mostraram significância estatística na diminuição das forças geradas. Quanto maior a intensidade de estiramento e tempo, maior a redução dos valores das forças geradas, entretanto os estiramentos 75% e 100% quando comparados entre si não apresentaram significância estatística. As cadeias elásticas do tipo curto foram capazes de promover a menor redução dos valores das forças geradas.

The aim of this study is to evaluate the reduction in the values of the forces generated by orthodontic chain regarding the intensity of stretching, time and configuration. Were used 432 segments of elastic chains, divided into 3 groups according to following configurations: short, medium and long. The chain segments were stretched at 25%, 50%, 75% and 100% and kept stretched in acrylic plates confectioned specially for this purpose, in distilled water, at constant temperature of 37°C, during periods of 0h, 24h, 1, 2, 3 and 4 weeks. The data were evaluated by analysis of variance (ANOVA) followed by Tukey test. All factors showed statistical significance in the reduction of forces delivered. The higher the stretching intensity and the time, the greater the reduction of the forces generated values. However the stretches of 75% and 100% when compared to each other were not statistically significant. The short elastomeric chain were able to promote the smallest reduction of the values of forces generated

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