Decoupling with Time
Where the Hierarchy of Bondability clarifies one of the challenges of adhesive dentistry, Decoupling with Time offers the solution. Another concept developed by Dr. David Alleman during his research into advanced adhesive dentistry and his Six Lessons Approach to Biomimetic Restorative Dentistry, Decoupling with Time overcomes the Hierarchy of Bondability by giving slow maturing bonds a head start before increasing the polymerization stress. This improves marginal integrity.
Doctors trained in the Biomimetic Mastership look at this photo and see molecules moving to create bonds to dentin. Understanding how adhesives bond to dentin is essential to creating a long-lasting restoration. Case by Dr. Davey Alleman, DMD.
Inventing the concept of Decoupling with Time
Dr. David Alleman began researching advanced adhesive dentistry in 1995 when he had questions his mentors weren’t able to answer, so he took to the published literature himself. With a goal of resolving post-operative sensitivity for his patients and understanding why some restorations failed, his literature review included articles by Carel L Davidson and Chantal Kemp Schulte on C-factor and polymerization dynamics of a new type of dental material — flowable composite.
The molecular makeup of the new flowable composite wasn’t different from previous composite, but it achieved superior results. In reviewing this article, Dr. David Alleman identified the variable: time. The time it took to place flowable composite allowed the bonds to mature to different substrates in the dental hard tissue, overcoming the Hierarchy of Bondability.
Flowable composite is placed during the resin coating step of a biomimetic restoration, as seen in his case by Dr. Davey Alleman, DMD.
How to increase bond strengths in dental restorations
Predictable caries removal
While bonding to caries-infected and -affected dentin is possible, it achieves lower bond strengths than bonding to sound dentin. Knowing exactly which substrate you are bonding to in different parts of the tooth — ideally sound dentin in the entire peripheral seal zone — starts with using caries detector dye. By staining denatured collagen, caries detector dye shows exactly where caries has taken root, helping doctors create consistent caries removal endpoints and visualize the hierarchy of bondability.
Caries detector dye (pink stain) shows exactly where bacteria has started to break down sound dentin. Case photo by Dr. Davey Alleman, DMD.
Gold standard bonding system
Gold standard bonding systems are those with long-term proven bond strengths that mimic a tooth’s natural connection to itself (30-50 MPa). While these dental bonding agents require advanced techniques to achieve these bond strengths, starting with a superior system will help maximize results.
Reducing C-factor stresses
Dental bonding systems are tested on flat surfaces, which do not account for C-factor. Defined as the ratio of bonded to unbonded surfaces, C-factor can reduce bond strengths as polymerizing composite moves to the most highly bondable surface. Understanding how to mitigate C-factor through prep design and stress reduction will help maintain the high bond strength of your gold standard bonding system.
Class II restorations are an example of a high C-factor prep design. Reducing the C-factor stresses of this restoration is essential for a strong bond to dentin. Case by Dr. Davey Alleman, DMD.
Essential steps before your adhesive layer
Decoupling with Time is outlined in Lesson 3 of Dr. David Alleman’s Six Lessons Approach to Biomimetic Dentistry. Part of the steps for immediate dentin sealing and resin coating, these Lesson 3 techniques are important to a successful adhesive restoration but not the most important. Lesson 1: Caries Diagnosis and Treatment and Lesson 2: Structural Analysis and Cracks into Dentin, ensure a predictable bonding surface and reproducible treatment of two dental pathologies that can cause post-operative sensitivity.
Learn more about Alleman Center biomimetic dentistry training programs teaching Dr. David Alleman’s Six Lessons Approach to Biomimetic Restorative Dentistry.
Watch Dr. David Alleman’s Six Lessons Approach Podcast episode to learn more about Decoupling with Time.
