Background:Macro-bond strength tests resulted in cohesive failures and overestimation of bond strengths. To reduce the flaws, micro-bond strength tests were introduced. They are the most commonly used bond-strength tests.Objective:Thus the objective of this review is to critically review the reliability of micro-bond strength tests used to evaluate resin-tooth interface.Data Collection:Relevant articles published between January 1994 and July 2013 were collected from Pubmed database, Google scholar and hand searched journals of Conservative Dentistry, Endodontics and Dental materials.Data Synthesis:Variables that influence the test outcome are categorized into substrate related factors, factors related to specimen properties, specimen preparation and test methodology. Impact of these variables on the test outcome is critically analyzed.Conclusion:Micro-bond tests are more reliable than macro-bond tests. However, no standard format exists for reporting the bond strength tests which could lead to misinterpretation of the data and bonding abilities of adhesives.

Adhesive systems are selected based on their bond strengths achieved while testing in laboratories. These bond strengths can predict the longevity of a restoration to some extent. There were several discrepancies in the reported bond strengths. To critically review the reliability of macro-bond strength tests used to evaluate resin-tooth interface. Relevant literature published between January 1983 and May 2013 was collected from PubMed database, Google scholar, and hand-searched journals of Conservative Dentistry, Endodontics and Dental materials. Variables that influence the test outcome are categorized into substrate-related factors, factors related to specimen properties, preparation of specimens, and test methodology. Impact of these variables on the test outcome is critically analyzed. There is lack of a standard format for reporting the bond strength tests, which could lead to misinterpretation of the data and bonding abilities of adhesives.

Aim:To evaluate the cytotoxicity of three root repair materials, mineral trioxide aggregate (MTA), Endosequence Root Repair Material and Biodentine in human periodontal ligament fibroblasts.Materials and Methods:Periodontal ligament fibroblasts were cultured from healthy premolar extracted for orthodontic purpose. Cells in the third passage were used in the study. The cultured fibroblast cells were placed in contact with root repair materials: (a) Biodentine, (b) MTA, (c) Endosequence, (d) control. The effects of these three materials on the viability of Periodontal ligament (PDL) fibroblasts were determined by trypan blue dye assay after 24 hours and 48-hour time period. Cell viability was determined using inverted phase contrast microscope.Statistical Analysis:Cell viability was compared for all the experimental groups with Wilcoxons matched pair test.Results:At the 24-hour examination period, all the materials showed increased cell viability. At 48-hour time period, there is slight decrease in cell viability. Mineral trioxide aggregate showed statistically significant increase in the cell viability when compared to other root repair materials.Conclusion:Mineral trioxide aggregate was shown to be less toxic to periodontal ligament fibroblasts than Endosequence Root Repair Material and Biodentine.