Monomer release from direct and indirect adhesive restorations: A comparative in vitro study

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Restorative Dentistry

Background:

• Computer-aided design and computer-aided manufacturing (CAD/CAM) enable indirect dental restorations.
• Understanding residual monomer release is crucial for patient safety in restorative dentistry.

Purpose of the Study:

• To compare monomer release between direct composite and indirect CAD/CAM restorations (composite, ceramic, hybrid).
• To evaluate the influence of luting materials and polymerization time on monomer elution.

Main Methods:

• Crown restorations fabricated from composite, ceramic, and hybrid CAD/CAM materials were luted onto tooth samples.
• Luted and non-luted restorations were immersed in an aqueous solvent for 8 weeks, with regular solvent collection and refreshment.
• Quantification of released monomers was performed using ultra-performance liquid chromatography-tandem mass spectrometry.

Main Results:

• Indirect restorations exhibited significantly lower residual monomer release than direct restorations.
• Monomers from luted indirect restorations primarily originated from the cementation composite material.
• Residual monomer release from direct restorations was highly dependent on light polymerization duration.

Conclusions:

• Indirect restorations offer a viable alternative to direct restorations for minimizing patient exposure to residual monomers.
• Minimizing the cement layer thickness in indirect restorations is essential for reducing monomer release.
• Further research into optimal cementation protocols for CAD/CAM restorations is warranted.