[Resin adhesion on the young permanent ground enamel (Report 3)]

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Adhesion Science

Background:

• Dental restorative procedures rely on effective adhesion between resin composites and tooth enamel.
• Understanding the impact of surface treatment and environmental factors like thermal cycling is crucial for long-term restoration success.

Purpose of the Study:

• To evaluate the effect of varying phosphoric acid etching times on resin adhesion to young permanent bovine enamel.
• To determine the influence of thermal cycling on the shear bond strength of resin-enamel interfaces.

Main Methods:

• Bovine incisor enamel specimens were etched for 0, 10, 20, 30, and 60 seconds using 40% phosphoric acid gel.
• Resin bonding agent and composite were applied, followed by 10,000 thermal cycles between 4°C and 60°C.
• Shear bond strength was measured, and fracture surfaces were examined using Scanning Electron Microscopy (SEM).

Main Results:

• The highest shear bond strength was achieved with 30 seconds of etching (45.21 ± 8.49 MPa).
• All etching times significantly improved bond strength compared to no etching.
• Twenty seconds of etching resulted in significantly lower bond strength than 10, 30, or 60 seconds.
• Thermal cycling significantly increased bond strength for 10, 30, and 60-second etching groups.

Conclusions:

• Thirty seconds of enamel etching provides optimal shear bond strength for the tested resin system.
• Thermal cycling positively influences resin-enamel bond strength, suggesting enhanced durability.
• SEM analysis indicated a correlation between enamel prism structure and bond strength, though not statistically significant.