While cement retained implants are widely popular, especially in the U.S., cement sepsis is one issue that is becoming increasingly clearer with cement retained implant restorations.
Cement sepsis is caused when residual cement is left around the implant which results in cement-induced peri-implantitis. Needless to say the results of having this occur can be severely devastating. If you are thinking to yourself, well that’s not happening with my cement retained implants, the scary part is that the literature shows it can take up to nine years for it to develop. The good news is there are some simple ways to avoid this, which is what I want to talk about in this article.
The biggest thing we can do to avoid this is to design our abutments appropriately. The key here, at least when it comes to being able to remove all your cement, is margin placement. Simply put, this means the margins must be easily accessible and must be no more than 1 mm subgingival. Personally in most cases, I place my facial margin 0.5 mm subgingival while my lingual margins are often either equagingival or even supragingival with the interpoximal margin being no more than 1 mm subgingival.
Cement retained implants: Some things to consider
When it comes to cement retained implants, it makes total sense to use a custom abutment – there are cases where a stock abutment can be used very well with no compromise. The catch when using stock abutments is, they nearly always need to be modified to work appropriately – which takes time and skill. And when these modifications are done by your technician, you can expect them to have a cost associated with them that will often make the total cost of the stock abutment and modification approach and possibly surpass the cost of a custom abutment.
In my opinion, the next most important consideration is cement selection for cement retained implants. While there are many choices when it comes to cements, the two most important factors are that it is radiopaque and easy to clean up. For me, this means resin cements are not a good option since they are all too difficult to clean up. In my hands I find Fuji Cem works well, which is a RMGI.
Another tip? Leave whatever you place over the abutment screw short of the top of the screw channel. Leaving the material short like this, my favorite thing to use is Teflon tape, leaves a ‘vent’ for excess cement to flow into the area thereby lowering the risk of hydrostatic pressure forcing cement subgingivally. While this certainly will not alleviate all the risk of cement being forced subginvially, it is so easy to do that it makes total sense for me.
Yet another thing to consider is placing retraction cord to act as barrier to cement being forced subgingivally in cement retained implants. The important thing to remember here is the cord needs to be placed in two pieces rather than one circumferential piece that is typically placed for an impression. The reasoning behind this is that if you place one piece from palatal to palatal line angle and a second from facial to facial line angle, you can reach in and grab an end and pull it out – rather than through the interpoximal as would be the likely result with 1 circumferential piece.
John R. Carson, DDS, PC, Spear Visiting Faculty and Contributing Author www.johncarsondds.com