Regional measurement of resin-dentin bonding as an array

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Adhesive Dentistry

Background:

• Microtensile bond testing has revealed significant variations in bond strengths between serial sections.
• The underlying reasons for these inconsistencies in resin-dentin bond strengths remain unclear.

Purpose of the Study:

• To investigate the consistency of resin-dentin bond strengths across the occlusal surface of coronal dentin.
• To determine if variations are material-dependent or technique-dependent.

Main Methods:

• Extracted human molars were prepared, and resin composite buildups were created using either One-Step or MacBond adhesives.
• Buildups were sectioned into 1x1x8 mm beams, with each beam assigned an x-y coordinate for tensile bond strength testing.
• Two clinicians performed parallel studies using the One-Step adhesive to assess inter-operator variability.

Main Results:

• Clinician A using One-Step showed large variations in bond strength, with many zero bonds in superficial dentin.
• Clinician B achieved significantly higher and more uniform bond strengths with One-Step compared to Clinician A.
• MacBond exhibited less variation in bond strength, with no zero bonds observed.
• Testing resin composite cylinders bonded with One-Step revealed minimal regional bond strength variation.

Conclusions:

• Significant regional differences in resin-dentin bond strengths exist across the occlusal surface.
• The primary factor influencing bond strength variability appears to be the operator's technique, not the bonding material.
• Resin-dentin bonds may possess less homogeneity than previously assumed, highlighting the importance of standardized application techniques.