Comparative Evaluation of the Efficacy of ProTaper & Mtwo Rotary Retreatment System and Conventional Hand H-files for Removal of Gutta-percha from Root Canal - A Stereomicroscopic Study.

BACKGROUND: Root canal retreatment aims to eliminate or substantially reduce the microbial load from the root canal and removal of previous root filling materials is the primary goal of nonsurgical retreatment. AIM: To comparatively evaluate the effectiveness of ProTaper retreatment files, Mtwo retreatment files, and Hedstrom files along with Gates Glidden (GG) Drill by using a stereomicroscope for the detection of remaining gutta-percha after root canal retreatment using a stereomicroscope. MATERIALS AND METHODS: Forty-five test samples were divided into three experimental groups (15 samples each), such as Group A-ProTaper retreatment files; Group B-Mtwo retreatment files; Group C-Hedstrom files along with Gates Glidden Drill. After routine endodontic treatment in the test samples, gutta-percha was removed from the test samples as per the division of different retreatment file systems. Further, test samples were divided longitudinally and were evaluated under the stereomicroscope. Stereomicroscopic images were captured and analysed under Image Analyser Software-Image J. STATISTICAL ANALYSIS: One-way ANOVA test was used for comparison of gutta-percha removal between the groups and Tukey's post hoc test was used for pairwise comparisons. RESULTS: The least remaining filling material was seen in specimens retreated with the ProTaper universal system. The highest remaining filling material was seen in specimens retreated with Hedstrom file with Gates Glidden Drill. CONCLUSION: All experimental test techniques left gutta-percha remnants within the root canal. ProTaper universal rotary retreatment system proved to be an efficient method of removing gutta-percha and left relatively less volume in comparison with other test systems.

Light-cured calcium hydroxide cements release of calcium ions using argon based induction coupled mass spectroscopy - an in vitro study.

Calcium ion-releasing ability of different calcium hydroxide-based pulp capping materials was comparatively evaluated in this study. Different brands of cements were taken from different manufacturers and categorized into three groups. Three different brands of Ca(OH)2 cements (Dycal, TheraCal, and Cal LC) were taken prepared by mixing and curing the cements as per the manufacturer's instructions. Consequently, ion release was measured after 7, 14, and 21 days by argon-based induction coupled plasma mass spectroscopy test. Within the limitations of this study, light-cured Ca(OH)2 cements released a higher amount of calcium ions compared with self-cured Ca(OH)2 cements. Theracal was found to be the highest light-cured calcium ion releasing materials throughout the period of 21 days. In conclusion, further clinical studies are warranted to substantiate the findings of this study.

Comparison of the Amount of Temperature Rise in the Pulp Chamber of Teeth Treated With QTH, Second and Third Generation LED Light Curing Units: An In Vitro Study.

Introduction: This in vitro study was designed to measure and compare the amount of temperature rise in the pulp chamber of the teeth exposed to different light curing units (LCU), which are being used for curing composite restorations. Methods: The study was performed in two settings; first, an in vitro and second was mimicking an in vivo situation. In the first setup of the study, three groups were formed according to the respective three light curing sources. i.e. quartz-tungsten-halogen (QTH) unit and two light-emitting diode (LED) units (second and third generations). In the in vitro setting, direct thermal emission from three light sources at 3 mm and 6 mm distances, was measured with a k-type thermocouple, and connected to a digital thermometer. For a simulation of an in vivo situation, 30 premolar teeth were used. Class I Occlusal cavity of all the teeth were prepared and they were restored with incremental curing of composite, after bonding agent application. While curing the bonding agent and composite in layers, the intrapulpal temperature rise was simultaneously measured with a k-type thermocouple. Results: The first setting of the study showed that the heat produced by irradiation with LCU was significantly less at 6 mm distance when compared to 3 mm distance. The second setting of the study showed that the rise of intrapulpal temperature was significantly less with third generation LED light cure units than with second generation LED and QTH light cure units. Conclusion: As the distance from the light source increases, less irradiation heat is produced. Third generation LED lights cause the least temperature change in the pulp chamber of single rooted teeth.