Point / Counterpoint

2. What is unique about CRA's work is the large number of different curing lights and different resins tested at the same time under controlled conditions. It is easy to be mislead when working with only one light and one resin, or even a couple of lights and resins. At this point in time, CRA has worked with 40 different light brands and 61 different resin brands, including several low shrinkage developmental resins which have confirmed that resin shrinkage is a key problem. Our work has shown that slow polymerization is a factor, BUT there is no resin formulation available commercially today where any commercially available resin curing light slows the polymerization once it starts. Once it starts it proceeds very rapidly, regardless of the light type and regardless of the light mode used.

Our work also showed clearly that used (dull) rotary burs and some finishing techniques create white lines and tooth cracking. We have literally watched ourselves produce effects while operating under a Zeiss stereo microscope at 10x with indirect lighting. With much effort, patience, and time, we have photographed these anomalies and published the photographs to document what we saw. We have had dental companies come to our lab and watch us work as we produced these effects repeatedly and predictably with certain combinations of resins and lights. Fast curing lights are simply not the problem claimed by Dr. Kanca.

3. CRA is the only center that has expended the time, effort, and money to test the effects of fast curing at the clinical level. CRA will monitor this work indefinitely into the future as long as we can locate the patients, 10 & 20 years from now. In addition, the sequel to this work has already been started on the clinical effects of fast curing vs. conventional halogen lights on microfill resins. These studies are a lot of work, but they should answer what has been a never ending theoretical debate - if Dr. Kanca will just look and listen and repeat the work himself, ad then report fully his methods and results for all to see.

4. We call for cooperation and scientific sharing rather than the current argumentive attitude and attempts to discredit each other's work. In the end, science has often found truth in what appear to be several opposing ideas. I submit discussions can be helpful and productive, arguments and anger are counterproductive.