Overestimating hybrid layer quality in polished adhesive/dentin interfaces

Area of Science:

• Dental Materials Science
• Adhesive Dentistry
• Microscopy Techniques

Background:

• Hybrid layer (HL) quality assessment traditionally relies on polished adhesive/dentin (a/d) interfaces.
• Existing methods often involve acid-bleach treatment, which may alter interface morphology.
• Smooth, acid-resistant layers are frequently reported, potentially masking complexities.

Purpose of the Study:

• To investigate if standard specimen preparation techniques (polishing, acid-bleach) modify the a/d interface.
• To determine if these techniques obscure the complexity and quality of the HL.
• To compare the effectiveness of conventional versus a multistep technique for interface evaluation.

Main Methods:

• Comparison of polished and unpolished specimens from the same tooth.
• Application of different acid-bleach chemical treatments.
• Utilized two one-bottle adhesives (3M Single Bond, Pulpdent UNO) with differing compositions.
• Examined resin-dentin interface morphology using scanning electron microscopy (SEM).

Main Results:

• Conventional polishing and acid-bleach treatments can negatively impact and hide structural details of the a/d interface, especially in porous HLs.
• The Pulpdent UNO/dentin interface demonstrated superior quality compared to the 3M Single Bond/dentin interface.
• Compositional differences influencing water interaction during wet bonding likely account for the quality variations.

Conclusions:

• Standard specimen preparation techniques can lead to inaccurate assessments of HL quality.
• A multistep technique effectively overcomes the limitations of conventional acid-bleach procedures in SEM interfacial morphology analysis.
• Pulpdent UNO exhibits a higher quality hybrid layer compared to 3M Single Bond, attributed to material composition.