We all know that bonding a Ti Base to zirconia in the lab eliminates the risk of having cement left uncleaned intraorally by the clinician. In a study, Gordon Christensen concluded this overflow of cement left uncleaned when cementing intraorally to be the number one cause of implant failure. As a result, this makes a great case for doing the cementing outside of the oral cavity, thus making the use of Ti Bases a most viable option.
Labs must know more about the cement process
So now that the cement process is moving into the lab there are some details we should be aware of. First, we MUST follow cement manufacturers instruction to the “T” to insure long lasting bond. In addition, prior to bonding check all the bonding components for expiration dates. If any of the components have expired, the bond strength will be compromised.
How do we maximize bond strength?
Many implant companies manufacturer Ti bases in one or sometimes two different heights. For instance 3 and 5 MM. In a study concluded a couple of decades ago 3M findings that minimum height for a Ti inserts to be 5 MM. I appreciate 3M for this research, however, the industry took this to mean that 5 MM is sufficient for all cases. I believe this thesis to be incorrect. For instance, many implant placements are in areas where there is severe bone resorption. It’s not unusual to have restorations that are 12-15 MM or taller. When cementing a 5 MM base into a 15MM restoration there are significant mechanical problems, especially when looking at lateral forces. This is not dissimilar to a preparation to crown ratio. In conventional C&B one would never expect a 3 to 1 ratio to last long term and we should feel the same about Ti Bases and zirconia.
Just how strong is the bond?
If we are to bond two parts together using proper materials and process the number one factor in bond strength is based on total surface area. The more the better. This fact, along, plus the known problem of debonding over time is an indication of the need for a taller Ti base that is 65-75% the height of the final restoration. Shorter than this is a compromise is optimal or potential bond strength.
As a result, Open Implants has developed a Ti Base with a cement interface that is 10 MM tall. In addition, OI has developed this component with circumferential cut lines to be shortened as needed, to 8, 6 or 4 MM. There is a corresponding DME file for each height available in both Exocad and 3Shape. We now have the opportunity to produce the ideal screw-retained restorations that will be less prone to problems such as breakage and or debonding.
Learn more about engaging and non-engaging Titanium Bases at openimplants.com/titanium-bases