RESUMO
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.
RESUMO
The prevalence of oral health problems in the global population is still high, especially dental caries, which is considered a multifactorial disease involving the role of bacteria, namely Streptococcus mutans. Gram-positive bacteria metabolize carbohydrates and sugars and convert them into lactic acid, causing dental caries. The peptidoglycan (PG) layer at the outer surface of the bacteria acts as protection. MurB enzyme is known for its contribution to PG biosynthesis. Gambir (Uncaria gambir Roxb.) is famous for many efficacies. Previous studies show that catechin from herb plants such as U. gambir has antibacterial activity. This study aimed to evaluate and predict the antibacterial activity of catechin from U. gambir against the MurB enzyme, which contributes to forming the bacteria PG, with an in silico approach. The structure of the MurB enzyme was collected from UniProt, and the ligands (catechin and chlorhexidine) structures were obtained from PubChem. The AutoDock software was used to dock both ligand and MurB enzyme visualized using PyMOL and analyzed using BIOVIA. The results showed that catechin has a binding affinity of more than - 7 kcal/mol against the MurB enzyme, and chlorhexidine has a higher binding affinity than catechin. Both catechin and chlorhexidine have similar amino acids attachment by hydrogen bonds. The results showed that catechin has competitive antibacterial activity against chlorhexidine in inhibiting the MurB enzyme.
