Evaluation of push-out bond strength of four luting agents and SEM observation of the dentine/fibreglass bond interface.

AIM: To assess the dentine/fibreglass-bonded interface by scanning electron microscopy and the push-out bond strength of four luting cements. METHODOLOGY: Forty root-filled human canines, with similar root lengths, were restored with fibreglass posts and randomly divided into four groups according to the cements employed (CG Gold Label I, RelyX ARC, BisCem and RelyX U100). After standardized post-space preparation, the root dentine was pre-treated for dual-polymerizing resin cements and untreated for the other cements. The mixed luting cement paste was inserted into root canals with a spiral filler and applied to the post-surface that was seated into the root canal. After 7 days, the teeth were sectioned perpendicular to their long axis into 1-mm-thick sections and submitted to a push-out test (1 mm min(-1)). Statistical analyses were carried out by two-way anova and Tukey's tests (P < 0.05). RESULTS: The bond strength was significantly affected by the type of cement (P < 0.001) and by the longitudinal region of the root canal (P < 0.031). All cements exhibited gaps at the dentine/cement interface. CONCLUSIONS: The self-adhesive materials and the glass ionomer cements had the highest push-out bond strength values when compared with the dual-curing resin cement.

Mineral content removal after Papacarie application in primary teeth: a quantitative analysis.

UNLABELLED: The aim of this study was to quantify the mineral content removed from primary teeth after using a chemomechanical system, called Papacarie. MATERIALS: Twenty human primary extracted molars were divided into two groups of 10 specimens each. Group A presented sound molars and Group B decayed molars on the occlusal or occlusal-proximal surface. In Group A, cavities in enamel and dentin with high speed drills were made before treatment. All teeth were treated with Papacárie following the manufacturer's instructions. Each cavity was filled in with the product, allowing curing for 45 seconds, and then removed with the non-cutting edge of the curette. The collected material was sent for laboratory analysis using atomic absorption spectrophotometry technique. Medians for each group were calculated through the application of Mann-Whitney and a statistically significant difference (p < 0005) was observed. To verify the quantity of calcium removed from sound tissue, the median of calcium in group A (0.08% Ca) was compared with that of the gold standard (0.04% Ca), which showed a close correlation of values between them. RESULTS: Indicate that the amount of calcium removed with Papacárie affects only the carious component of teeth. This goes in accordance with the principles of cavity preparation and follows the current philosophy of preventive dentistry.

The utilization of saliva as an early diagnostic tool for oral cancer: microRNA as a biomarker.

Recently, dentistry presents a preventive philosophy, seeking early diagnoses and minimally traumatic treatments for patients. Cancer is known for its aggressive nature, where its signals and symptoms may only appear in advanced stages of the disease, therefore, reducing the possibility of using atraumatic treatment options and patient survival. Saliva has in its composition substances which can be used as biomarkers for disease diagnoses, one of those being microRNA. microRNAs are a group of small RNA molecules with 18-24 nucleotides which have functions such as the degradation of oncogenes transcripted mRNA. The aim of this paper is to explore all theoretical possibilities that microRNA offers as an early diagnostic tool for oral cancer. Studies show that microRNA can be directly linked with cancer gene regulation. Because microRNA is more specific to tissues and diseases than mRNA, it holds the premise of being a feasible, non-invasive, and stable biomarker for early diagnosis of oral cancer. The fact that miRNA can be found in saliva makes it an extremely affordable and feasible option as a biomarker to be used. Since it is linked to regulating functions of cancer genes, it also brings hope that in the near future, it could be used as a reliable biomarker.