Effect of protective coating agents on microleakage and flexural strength of glass ionomer cement and zirconomer. an in vitro study

PURPOSE

The objective of this study was to assess the microleakage and flexural strength of glass ionomer cement (GIC) and modified GIC (Zirconomer) when coated with protective coating agents such as COAT-IT and G-COAT plus.

METHODS

Sixty tooth specimens were grouped into two groups based on the type of restorations (GIC (n = 30) and Zirconomer (n = 30)). The samples were further divided into three subgroups (n = 10) based on the protective coating agent (Petroleum jelly, G-COAT Plus, or COAT IT) applied. This study evaluated the microleakage at the occlusal and cervical margins of class V restoration after being subjected to dye penetration and sectioning. Each specimen was viewed under a 40 × microscope and was given scores based on the depth of dye penetration. They were statistically analyzed using the Kruskal-Wallis test and compared within the groups using the Mann- Whitney Test. In addition, flexural strength was assessed using standardized cuboid (25 × 2 × 2 mm) specimens of restorative materials with and without protective coating agents. The mean flexural strength data of all the subgroups were statistically evaluated using a one-way analysis of variance (ANOVA) and compared within the subgroups using the student t test.

RESULTS

A statistically significant difference was found when occlusal margin microleakage scores were evaluated with G-COAT Plus demonstrating the lowest occlusal margin microleakage when applied over GIC restoration. The increasing order of occlusal margin microleakage scores is as follows: GIC with G-COAT Plus, Zirconomer with COAT-IT, GIC with COAT-IT, GIC, Zirconomer with G-COAT Plus, and Zirconomer. However, the cervical margin microleakage scores revealed no significant difference. While flexural strength was found to be highest for the GIC group coated with G-COAT Plus, it was observed that there was a significant improvement in the flexural strength of both GIC and Zirconomer when coated with either of the protective coating agents.

CONCLUSION

Within the limitations of this in vitro study, it was observed that the application of protective coating agents can significantly reduce the potential microleakage and improve the flexural strength of the restorative material especially when zirconia-reinforced GIC is the restorative material.

Evaluation of academic performance of undergraduate dental students in a government medical university in Kerala, India

Introduction

Dentistry is considered to be a high-stress profession. The educational period in dental schools is viewed as a highly demanding and stressful learning environment. The aim of the study was to evaluate the academic performance of undergraduate dental students of 2010, 2011, and 2012 batches admitted at Kerala University of Health Sciences.

Materials and Methods

The present retrospective study evaluated the performance of dental students of 2010, 2011, and 2012 batches from their first Bachelor of Dental Surgery (BDS) to the completion of final BDS Part 2 examination. The study was carried out from August 2010 to March 2017. The data were analyzed using SPSS version 19 software. Chi-square test was used for analyzing the significance of difference between proportions. The level of significance was set at P < 0.05.

Results

The results of first BDS students of 2010, 2011, and 2012 batches were 35.8%, 49.9%, and 55.5%, respectively. Whereas, the results of the final BDS Part 2 students of 2010, 2011, and 2012 batches were 92.6%, 88.4%, and 92.5%, respectively.

Conclusion

The present study shows a decline in performance of dental students at the time of inception of the university, and as time progressed, the results of the students showed significant improvement.