Oxygen inhibition layer: A dilemma to be solved

Area of Science:

• Dental Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• The oxygen inhibition layer (OIL) forms on the surface of uncured dental composites.
• Understanding OIL's impact on inter-layer adhesion is crucial for composite restorations.

Purpose of the Study:

• To evaluate the thickness of the OIL on different composite types.
• To compare the interlayer shear bond strength (SBS) after various OIL treatments.

Main Methods:

• Tested three composite types: nanohybrid, microhybrid, and short glass fiber-reinforced.
• Applied surface treatments: no treatment, ethanol, water spray, and SiC paper grinding.
• Measured OIL thickness and performed interlayer SBS testing.

Main Results:

• Glass fiber composites exhibited higher interlayer SBS than nanohybrid and microhybrid composites.
• Untreated controls (retaining OIL) showed higher SBS than SiC paper treated groups.
• Ethanol and water spray treatments did not fully remove the OIL, maintaining improved SBS.

Conclusions:

• The presence of the OIL is beneficial for interlayer SBS and durable adhesion.
• Absence of OIL negatively impacts bond strength, leading to interfacial failures.
• Glass fiber composites offer superior interlayer bond strength.