What should you look for in a luting composite?
I have received a number of e-mails during the last few weeks asking me what cement I am using for porcelain veneers. I thought this would be an excellent topic for a series of blog posts that would cover the materials I am using when I am bonding in a veneer case.
The first thing that I would like to point out is that I actually have 3 different kits of veneer luting composite in the practice that I like to use for different cases. Each kit is from a different manufacturer and each has a different amount of viscosity and opacity along with different shades for me to select from. The reason I have 3 kits is that there are some patients when I cannot find the correct shade or opacity of resin cement to match the surrounding dentition. In these cases, I will turn from my primary kit to one of the other 2.
The kits I use all have been designed with two areas in common. The first commonality is that each kit is designed as a light cured only system. I prefer to have complete control when I am bonding porcelain veneers into place. To maintain control the cement is only cured when I am 100% confident the restoration is seated in the correct orientation and all the margins are closed. This is only really possible with a light cured only luting composite. If you are a little slow with a dual cured system you may not have the restoration completely seated when the cement starts to set and you will be left with a poorly fitting restoration and open margins. I also prefer to spot cure my veneers into place and clean the interproximal excess before curing the overall body of the veneer.
Another benefit of using luting cement designed to only be light-cured is that the cement itself does not contain the unreacted amines necessary to react with the peroxides in the catalyst needed with a dual-cure cement. The bottom line is that this makes the cement much more color stable. The dental literature reports a potential color stability problem with cements that are designed to be both light-cured and dual-cured when used with the dual cured catalyst. This may not be a problem with a larger porcelain onlay but with a thinner porcelain veneer any change in the luting cement color over time may result in a change in the veneer and an unhappy patient.
The second important area in common with the 3 kits is that they all have a water-soluble try-in gel that allows me to test out the selected shade of luting composite before I commit to bonding the restoration into place. I feel this is a very important feature to have with any kit designed to lute porcelain restorations because the luting composite will affect the value and color of the veneers.
The next area you will want to look at are the actual physical properties of the materials. The manufacturers are providing us with many excellent products in the dental field but my preference with porcelain veneers is to use materials that have a number of years (preferably 5 years, check out the pictures below from a 4 unit veneer case that was 6 years old last month) of clinical evidence supporting their use. I would like a color stable material with a low film thickness and excellent compressive, flexural and tensile bond strength that is easily polymerized in the 400 to 500 nm wavelength.
I would also like a material that will clean up easily around the porcelain restorations
Next week, in part 2 for this series I will let you know the kit that I use for the majority of my porcelain veneer cases. Can you guess what this kit is?
If you have any questions or comments, please feel free to leave them using the link above.