Maryland Bridge Design: One Retainer or Two?
There are many challenges to fabricating Maryland Bridges with the CEREC system. Some of the most common include:
- Designing in the Chairside CEREC Software
- Material issues
- Milling accuracy due to the sprue location on the internal of one of the wings
When trying to solve these issues, there are a few different alternatives:
- Using the inLab software so you can mill permanent materials in the Bridge Mode (makes design much easier)
- Using one retainer instead of two so you can sprue more easily and fit the restoration into a single block
The idea of one retainer resin-bonded fixed prostheses was a foreign concept to me until very recently. If you think about the forces involved it just makes sense. Even then, it still seemed not right. That was until I recently met Dr. Matthias Kern of the University of Keil in Germany. He talked about his extensive long term research on the subject and supported it by literature:
J Adhes Dent. 2011 Oct;13(5):407-10. doi: 10.3290/j.jad.a22096.Ten-year survival of anterior all-ceramic resin-bonded fixed dental prostheses
J Dent. 2012 Sep;40(9):783-6. doi: 10.1016/j.jdent.2012.05.009. Epub 2012 Jun 1.
Randomized clinical trial on single retainer all-ceramic resin-bonded fixed partial dentures: Influence of the bonding system after up to 55 months.
Quintessence Int. 2005 Feb;36(2):141-7.
Clinical long-term survival of two-retainer and single-retainer all-ceramic resin-bonded fixed partial dentures.
I am now a believer... and look forward to putting this technique into my arsenal. Another great option for temporary or permanent tooth replacement in the Anterior.
