TBU # 008: Biomimetic Tip Tuesday: What to do with Sclerotic Dentin

What are we supposed to do with Sclerotic Dentin? 

Sclerotic dentin can be a confusing thing to deal with.  Especially if we are trying to keep our preps as clean as possible.  Are we supposed to remove it? Do we leave it? Can we bond to it? There can be quite a few questions that arise when we are faced with it.

First off, lets define what is sclerotic dentin. 

Sclerotic dentin can be defined dentinal tables that have become completely obliterated by the calcification, or deposition of peritubular dentin.  Its part of the traumatic response done by the odontoblasts.  It is often called "white zone" or transparent dentin.

This layer of sclerotic dentin can beneficial to us in our bonding.  Its been shown that if its treated correctly it can improve our bond strengths.  The opposite is also true.  If its been neglected or has received poor treatment, it will have an adverse effect to our bond strengths.  

Ok so how do we treat it?

Our friend Dr. Fusayama studied a lot on caries and dentin bonding with the total etch approach.  In both of his protocols, he recommends leaving sclerotic dentin and that it should be preserved.  

Dr. Fusayama's total-etching approach was dry bonding, which requires you to air dry after the etch has been placed and washed.  The air drying could lead post operative sensitivity, poor bond strengths, etc. However, with the presence of sclerotic/transparent dentin would often help limit these symptoms due to it being less permeable.  

With a total-etch approach, like Optibond FL from Kerr, I recommend roughening sclerotic dentin, etching for 20-30 seconds, as compared to 15 seconds for normal dentin, then slightly drying as normal, then proceed

With a self etching approach, like SE Protect from Kuraray, I recommend using air abrasion on sclerotic dentin for an additional 10-20 seconds followed by the self etching primer for 30 seconds.  I'll often use a few coats of primer to ensure adequate etching. Dry as normal, then proceed.

So in review, if all possible, its best to leave the sclerotic dentin and then give it a little extra conditioning with the etch!  

Resources:

1. The microtensile bond strength test: Its historical background and application to bond testing. 

2.Clinical guidelines for treating caries in adults following a minimal intervention policy - Evidence and consensus based report.

3. A Comparative study of the microtensile bond strength and microstructure differences between sclerotic and normal dentine after surface pretreatment. 

Photo credit: Zakariae Ibn Attya