There’s a bit of controversy in the literature about the use of zirconia as an implant abutment. Perhaps you’ve heard something about fractures?
I do trust zirconia as an abutment material, but only under certain circumstances. First, let’s chat about why I use them at all.
Zirconia abutment for implant in the maxillary lateral incisor position.zirconia abutments at all.
The main reason I will choose a zirconia abutment is if the gingiva exhibits a thin biotype. “Periodontal biotype” was a term coined by Lindhe and Siebert in 1989 with notable developments of the concept by Claffey and Shanley in 1986 and Lindhe and Olsson in 1991. Essentially, there is a spectrum of thicknesses of gingiva in the population which we often note as being either thick or thin. Why do we care?
Thin tissue can transmit the unesthetic gray hue of the abutment to our eyes. Yucky. In the case to the left, we have a beautiful PFM crown on a cast abutment on implant in the right lateral incisor position. The crown isn’t the problem. The esthetics are compromised because of thin tissue that can’t hide the gray abutment underneath. The gray hue can also be coming from the implant platform.
How do we find out if the biotype is thick or thin before we order the abutment? My favorite method is totally simple. Kan, et al. described the simple technique of placing a metal periodontal probe into the gingival sulcus. If you can see the probe, you have a thin biotype. Brilliant!
So if your patient has a thin biotype, you may want to consider using zirconia since its bright white color looks better under the tissue. Can it fracture? Yup. It’s happened to me.
Zirconia abutment fractured at the internal connection.
Fortunately this abutment on the left fractured before it was inserted in the mouth. There are a number of reports of zirconia abutment fractures but it really depends on the implant manufacturer’s design. Some companies have products that will fracture more often than others. The above case was for a small diameter platform, which logically be more likely to fracture. Additional contributing factors are related to the force that is expected to be loaded on our little friend. Strong bites, more posterior implants, and bruxism would certainly make me think twice about using a zirconia abutment.
What if you still want the esthetics of zirconia but you are worried about it fracturing? I use a technique taught to me by Marotta Dental Studio to solve the problem. We use a metal abutment (stock or custom) and apply opaquing porcelain to the surface. That will successfully block out the gray hues as you can see in this case here:
Metal abutment treated with opaquing porcelain.
Here’s the gist: I’ll use a zirconia abutment for thin biotypes in the esthetic zone. If I have a narrow diameter implant and/or high stress factors, but I still want the esthetics that zirconia can offer, I prefer to use the opaquing porcelain technique.