Gary M. DeWood, DDS, MS
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It’s always a wonderful day in the office when we seat anterior esthetic porcelain restorations, although the wonderfulness actually only happens when the patient exits the operatory and proceeds happily to the mirror to enjoy the reflection of a new smile.
Prior to that moment, the office is at DENTCON 1. (DENTCON — Dentistry Condition — numbers are related to DEFCON — Defense Condition — numbers used by the U.S. Defense Department. DEFCON 5 is defined as normal peacetime readiness and DEFCON 1 connotes maximum force readiness for a nuclear event.)
Placement of ceramics, especially anterior partial coverage ceramics, is so technique-sensitive that for most of us these procedures can be counted on to create DENTCON 1 stress. Until recently, one of the most stressful parts of this process for me was the cleanup of the excess material around the margins. Bonding is what makes ceramic veneers possible, and we always want excess resin to be expressed as we seat. I try to remove most of the excess prior to covering with glycerin and curing, but there is always plenty left in places where I do not want it. I hate that part.
During a recent visit to Ivoclar’s headquarters, I had an opportunity to see the effect of silane and silane type materials on the bond between ceramic and resins.
In the exercise we performed, it became very clear to me that 1) silane increases the bond strength between these two materials when the ceramic is etched, and 2) silane creates a connection with any ceramic, etched or not. I thought back to the last anterior partial coverage case I had seated — to the pulling, the pushing, the picking, and the work to remove those bits of excess material at the margin. I realized I was fighting with a silanated surface, trying to hold on to that resin.
In the past, I had always handled silane application with care but had not considered where the silane was going. I often filled the restoration and then blew air to dry it, coating not only the intaglio surface but also portions of the glazed or polished areas at the margins. I confirmed this effect upon my return by filling some crowns and drying them with air. I knew I wanted to seat my next case differently.
I decided to watch what happened as I placed the silane, and was determined not to have any on the exterior surfaces of my restorations. Application was accomplished under magnification (Zeiss PROergo microscope at about 7 power) with a microbrush. I observed some interesting things happening with my improved view. The silane spread and ran on the ceramic surface. I learned to control this effect so that the silane ran to the margin and stopped when it encountered the polished edge. I seated the silanated restorations with Rely-X veneer cement, cured as usual, and removed the excess with the least effort I have ever needed since there was no effort by the ceramic to hold on to it.
I know that every seating appointment for veneers will take me to DENTCON 1. I am a dentist and cannot help it, but the return to DENTCON 5 has been made faster and more predictable because the resin does not stick. This means more peacetime for my patients, team, and me.
Gary M. DeWood, DDS, MS, earned a DDS from Case Western Reserve University in Cleveland, Ohio, and an MS in biomedical sciences from the University of Toledo College of Medicine. He serves as executive vice president for curriculum for Spear Education, teaching and practicing in Scottsdale, Ariz. Contact him at [email protected].
