Can lasers replace conventional methods in optimizing bond strength of bioactive materials?

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Restorative Dentistry

Background:

• Bioactive restorative materials offer potential benefits like ion release and self-healing properties.
• Dentin surface preparation methods, such as high-speed bur cutting and Er,Cr:YSGG laser ablation, can influence the bonding efficacy of restorative materials.
• Understanding the interaction between material composition and surface treatment is crucial for predictable clinical outcomes.

Purpose of the Study:

• To evaluate and compare the shear bond strength of four distinct bioactive restorative materials bonded to dentin prepared by a high-speed diamond bur or an Er,Cr:YSGG laser.
• To investigate the influence of dentin surface preparation method on the bond strength of different bioactive materials.
• To assess the failure modes at the resin-dentin interface.

Main Methods:

• An in vitro study involving 120 extracted human molars.
• Dentin surfaces were prepared using either a high-speed diamond bur or an Er,Cr:YSGG laser.
• Four material types were tested: glass hybrid (EQUIA Forte HT), bioactive resin composite (Activa BioActive-Restorative), giomer (Beautifil II), and alkasite (Cention Forte).
• Shear bond strength was measured using a universal testing machine; SEM analysis examined the interface.

Main Results:

• Alkasite (Cention Forte) exhibited the highest shear bond strength irrespective of the dentin surface preparation method.
• Glass hybrid (EQUIA Forte HT) demonstrated the lowest bond strength.
• Laser preparation significantly reduced bond strength for the bioactive resin composite (Activa BioActive-Restorative) compared to bur preparation.
• Failure analysis indicated a predominance of adhesive failures, with some cohesive failures observed.

Conclusions:

• The bonding performance of bioactive restorative materials is significantly influenced by both their intrinsic properties and the method of dentin surface preparation.
• Cention Forte (alkasite) provides the most reliable adhesion to dentin, regardless of whether it is prepared with a bur or a laser.
• Clinicians should consider the interplay between material choice and surface preparation technique for optimal bonding outcomes in restorative dentistry.