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BACKGROUND: A systematic review with meta-analysis was conducted to assess the effect of adding potassium nitrate to carbamide peroxide gels on bleaching efficacy and on reducing the risk and intensity of tooth sensitivity. METHODS: PubMed, Scopus, Web of Science, LILACS, BBO, and Cochrane Library databases and the gray literature were searched. IADR abstracts, records of trials, dissertations and theses were also searched. The Cochrane Collaboration risk of bias tool was used to assess the quality of the studies. RESULTS: Six studies were included in the systematic review and most of them had unclear risk of bias for the key domains, and of these only five were included in the meta-analysis. The risk ratio (RR) for sensitivity was 0.93 (95% CI = 0.73 to 1.19, P = 0.56). The standardized mean difference for pain intensity was -0.10 (95% CI = -0.36 to 0.16, P = 0.45), and for colour change was 0.12 (95% CI = -0.22 to 0.46; P = 0.49). CONCLUSIONS: No significant differences were observed between the groups with and without addition of the desensitizer in the gel. The addition of potassium nitrate to carbamide peroxide gel did not reduce the risk and intensity of tooth sensitivity during at-home bleaching. Colour change was not influenced by the addition of potassium nitrate to the gel.

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Leucocyte- and platelet-rich plasma (L-PRP) is an autogenous platelet concentrate enriched with leukocytes that releases various growth factors responsible for the proliferation, regulation, and differentiation of mesenchymal cells during wound healing. Since the bone and medullary tissue are contiguous and share the same origin, this study evaluated the effect of L-PRP on the repair of calvaria bone using histomorphometric analysis of the newly formed bone, and compared the results in the presence of osteocalcin (OC) and peroxisome proliferator-activated receptor gamma (PPAR-γ) detected by immunohistochemistry. Artificial circular bone defects (5mm diameter) were produced in the calvaria of 42 rats. The defects were treated with autograft, autograft combined with L-PRP, or without grafting material (sham). The animals were euthanized at 15 or 40 days postsurgery (n=7 in each group). Data obtained were analyzed by Student-Newman-Keuls test for histomorphometric and immunohistochemical interpretation. The development of bone matrix was significantly less in the defects treated with L-PRP, while the medullary area composed of fatty cells was larger. This coincided with the minor expression of OC and expressive presence of PPAR-γ. These results suggest that L-PRP may impair osteoneogenesis and alter the ratio of differentiation between bone matrix and fatty cells, increasing the medullary tissue.

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Dual-cured cements have been studied in terms of the hardness or degree of conversion achieved with different curing modes. However, little emphasis is given to the influence of the curing method on other mechanical properties. This study investigated the flexural strength, flexural modulus and hardness of four proprietary resin cements. Materials tested were: Enforce and Variolink II (light-, self- and dual-cured), RelyX ARC (self- and dual-cured) and C & B (self-cured). Specimens were fractured using a three-point bending test. Pre-failure loads corresponding to specific displacements of the cross-head were used for flexural modulus calculation. Knoop hardness (KHN) was measured on fragments obtained after the flexural test. Tests were performed after 24 h storage at 37 degrees C. RelyX ARC dual-cured showed higher flexural strength than the other groups. RelyX ARC and Variolink II depended upon photo-activation to achieve higher hardness values. Enforce showed similar hardness for dual- and self-curing modes. No correlation was found between flexural strength and hardness, indicating that other factors besides the degree of cure (e.g. filler content and monomer type) affect the flexural strength of composites. No statistical difference was detected in the flexural modulus among the different groups.

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PURPOSE: To determine the tensile bond strength of three filled and two unfilled adhesives applied to bovine dentin. MATERIALS AND METHODS: Fragments of the labial dentin of bovine incisors were embedded in PVC cylinders with self-cure acrylic resin, and ground flat using 200 grit and 600 grit sandpaper. The following adhesive systems were tested (n=10): Prime & Bond NT, Prime & Bond NT dual cure, Prime & Bond 2.1, OptiBond Solo and Single Bond. A 3 mm-diameter bonding surface was delimited using a perforated adhesive tape. After etching with 37% phosphoric acid and adhesive application, a resin-based composite truncated cone (TPH, shade A3) was built. Tensile test was performed after 24 hrs storage in distilled water at 37 degrees C. Failure mode was accessed using a x10 magnification stereomicroscope. RESULTS: Weibull statistical analysis revealed significant differences in the characteristic strength between Single Bond and Prime & Bond NT dual cure, and between Single Bond and Prime & Bond 2.1. The Weibull parameter (m) was statistically similar among the five groups. Single Bond and Prime & Bond NT showed areas of dentin cohesive failure in most of the specimens. For OptiBond Solo, Prime & Bond NT dual cure and Prime & Bond 2.1 failure was predominantly adhesive.

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