To evaluate and compare the efficacy, cleaning ability of hand and two rotary systems in root canal retreatment.

AIM: To evaluate and compare the efficacy, cleaning ability of hand and two rotary systems in root canal retreatment. METHODOLOGY: Sixty extracted premolars were retreated with following systems: Group -ProTaper Universal retreatment files, Group 2-ProFile system, Group 3-H-file. Specimens were split longitudinally and amount of remaining gutta-percha on the canal walls was assessed using direct visual scoring with the aid of stereomicroscope. Results were statistically analyzed using ANOVA test. RESULTS: Completely clean root canal walls were not achieved with any of the techniques investigated. However, all three systems proved to be effective for gutta-percha removal. Significant difference was found between ProTaper universal retreatment file and H-file, and also between ProFile and H-file. CONCLUSION: Under the conditions of the present study, ProTaper Universal retreatment files left significantly less guttapercha and sealer than ProFile and H-file. CLINICAL SIGNIFICANCE: Rotary systems in combination with gutta-percha solvents can perform superiorly as compared to the time tested traditional hand instrumentation in root canal retreatment.

Effect of saliva and blood contamination on the bond strength of self-etching adhesive system- An in vitro study.

AIM: The aims of this study were to determine the effect of saliva and blood contamination on the shear bond strength of self-etching adhesive to enamel and dentin; and, to compare the difference in bond strength due to contamination beforeand after application of the self-etch adhesive. MATERIALS AND METHODS: 40 human mandibular molars were wet ground on both buccal and lingual surfaces to prepare flat superficial enamel and dentin surfaces. They were randomly divided into two groups (n = 40) based on the substrate (enamel and dentin). Each group was further divided into five subgroups (n = 8) based on the type of contamination it was subjected to, and the step in the bonding sequence when the contamination occurred (before or after adhesive application). Fresh saliva and fresh human blood were applied either before or after the application of Xeno III(®) self-etching adhesive system (SES). Composite resin was applied as inverted, truncated cured cones that were subjected to shear bond strength test. STATISTICAL ANALYSIS: One-way analysis of variance (ANOVA) and Tukey's Honestly Significant Difference (HSD) test were used. RESULTS: Statistically significant reduction in the bond strength was shown after both saliva and blood contamination before and after Xeno III(®) application (P< 0.05). Bond strength is significantly reduced after contamination with blood as compared to saliva. CONCLUSIONS: When self-etching adhesive systems are used, saliva and blood contamination significantly decrease the bond strength of the adhesive to enamel and dentin of the tooth.