The article: Cariostatic & Ultraconservative Sealed Restorations: nine year results among children & adults
The journal: ASDC J Dent Child. 1995 Mar-Apr;62(2):97-107.
The author: Mertz-Fairhurst, et all
Why we should know it: The Department of Restorative Dentistry where I went to dental school (UTHSCSA) based much of their caries control philosophy on this series of articles by Mertz-Fairhurst out of Medical College of Georgia School of Dentistry. Dr. Jim Summitt cites this article over and over in his text "Fundamentals of Operative Dentistry." My attending operative professor in dental school, Dr. J.D. Overton drilled this article into us. This article and its predecessors by the same authors shape the way restorative dentists have begun to think about caries.
What we need to know: The study is very basic, but what makes it a phenomenal study is it's longitude. The authors were able to track restorations at 3, 6, and 9 years and have done an excellent job of compiling the data. To summarize, the authors basically took carious lesions on posterior teeth. In all groups, the enamel was beveled but carious dentin was left remaining in the tooth. The first group was restored with a sealed composite restoration. Another group was restored with amalgam sealed with resin composite. A third group was prepared traditionally with extension for prevention and restored with traditional amalgam.
The results are quite remarkable. After 9 years, sealants remained intact in 64% of the sealed composite restoration group and in 83% of the sealed amalgam group. The cumulative failure rates were as follows:
-Sealed composite restorations: 16%
-Sealed amalgam restorations: 2.5%
-Unsealed traditional amalgam restorations- 17%
This study shows that class I caries can be arrested if sealed properly. Obviously, I don't believe the authors recommend leaving carious dentin behind out of laziness. But in situations where caries can not be removed without endangering the pulpal status of the tooth, caries can be left with one caveat. The restoration must be well sealed. Isolation and environment are obviously vitally important for this as well as clean decay-free beveled enamel. In my practice, 99% of posterior restorations I do are resin composite. With that, I feel the need to use a rubber dam on virtually every restoration I do. If you are going to consider leaving carious dentin, I would recommend applying a rubber dam if you have not done so already.
I will cover my rubber dam technique in a later article. It is much simpler and easier than the rubber dams we were all taught in dental school.