Effect of different surface treatments on shear bond strength of ceramic brackets to old composite

The Role of Duration of Chlorhexidine Gluconate 2% Application on the Shear Bond Strength of a Total Etch Bonding Agent: A Comparative Study

Introduction

Matrix metalloproteinases enzymes (MMPs) can degrade the hybrid layer which can cause failure of composite restorations. Chlorhexidine gluconate 2% can reduce MMPs activity and increase the bond strength of the resin to dentin.

Purpose

This study aims to determine the role of the duration of chlorhexidine gluconate 2% application on shear bond strength of a total-etch bonding agent.

Methods

A total of 36 freshly extracted maxillary premolars were removed occlusally by one-third of the crown using a carborundum disc until the dentin was exposed. Specimens were divided into four groups n(9). The dentin surfaces were etched for 5s. Group A is the control group. In group B, chlorhexidine gluconate 2% was applied for 30s. In group C, chlorhexidine gluconate 2% was applied for 60s. In group D, chlorhexidine gluconate 2% was applied for 90s. The universal adhesive was applied afterwards and then followed by composite to the dentin surface. All specimens were stored in artificial saliva at 37°C for 24 hours. The shear bond strength was tested using a universal testing machine.

Results

There was an increase in the shear bond strength of the bonding agent along with the additional application duration of chlorhexidine gluconate 2%. All groups gave higher MPa values than the control group. The shear bond strength in group A (control) was 12.64 MPa; Group B (30s of chlorhexidine) was 16.93 MPa; Group C (60s chlorhexidine) was 18.23 MPa; group D (90s of chlorhexidine) was 18.47MPa.

Conclusion

Duration of chlorhexidine gluconate 2% application affects the shear bond strength of the bonding agent with the total-etch system. The effective duration of chlorhexidine gluconate 2% for the restorative procedure is 60 seconds.

Knowledge, attitude, and awareness regarding the use of composites for orthodontic purposes among dental students

The aim of the study was to determine the knowledge, attitude, and practice regarding the use of composites for orthodontic purposes among dental students. The questionnaire was designed to evaluate knowledge, attitude, and awareness. Google Forms was used for the distribution of questions. This is a questionnaire survey based on knowledge, attitude, and awareness regarding the use of composites for orthodontic purposes among dental students; 86% of them had awareness regarding the use of composites for orthodontic purposes, wherein the remaining 14% were not aware. Considering the limitations of the study groups, we can conclude that the knowledge, attitude, and awareness regarding the use of composites for orthodontic purposes among dental students were good. However, there is still a lack of knowledge in few perspectives which can be overcome with continuous dental education programs and lectures.