Dark Tissue Around Implants?

I see a lot of patients in my practice who come in because they want to improve the esthetics of their implant restoration, specifically the dark tissue they see around the implant crown. 

Although multiple reasons exist as to why the tissue is dark, the two most common causes are:

• Color/material of the abutment
• Facial soft tissue thickness

The patient in Figure 1 didn’t like the metal showing on the implant crown and the dark color of the surrounding tissue. Given the metal abutment showing above the gingival margin, the question is, “Will the tissue color come back to normal if we just use an esthetic custom abutment or do we also need to increase the thickness of the facial soft tissue?”  

In 2008, Jung and colleagues published a paper on this exact question.¹ In this study, they analyzed the effect of titanium and zirconia with and without veneering ceramic on the resultant color of the tissue with three different thicknesses. Connective tissue grafts were used to vary the tissue thickness between 1.5, 2.0, and 3.0 mm. The color of the tissue was evaluated with a spectrophotometer and also with the naked eye. The results show that all restorative materials induced overall color changes; however, the color changes diminished with an increase in soft tissue thickness. It is not surprising to see that titanium induced the most prominent color change.  

Zirconia on the other hand did not induce visible color changes in tissue thicknesses of 2.0-3.0 mm, regardless of whether it was veneered or not. It is interesting to note that if the tissue thickness was 3.0 mm, no change in color could be distinguished by the human eye with either titanium or zirconia.

So with regard to the patient in Figure 1, we know that zirconia would present the least color change. However, given the thinness of the facial tissue, zirconia would still present “some” change in color (tissue is <1 mm thick). With this in mind, the decision was made to thicken the facial tissue with a connective tissue graft prior to the new implant restoration. Due to the angulation of the implant and the thinness of the facial wall of the abutment, the definitive abutment chosen was a custom UCLA-metal ceramic abutment. The metal would provide strength greater than that of zirconia. The sub-gingival region of the abutment would be baked with ceramic so as not to negatively influence the color of the facial soft tissue.

Figure 2 shows the abutment during try-in (note the increased thickness of the facial soft tissue). The definitive restoration (metal ceramic crown) blends in nicely with the un-restored lateral incisor and the natural soft tissue esthetics has been restored. (Figure 3)

(Click this link to learn more about correcting an un-esthetic implant with a pediculated connective tissue graft.)

It is important to remember that in order to improve the soft tissue esthetics around an implant, the decision does not lie solely on choosing the correct material for the abutment. The thickness of the facial soft tissue may be the most crucial factor in terms of correcting tissue discoloration around implant restorations.

(Click this link for more articles by Dr. Gregg Kinzer.)

Gregg Kinzer, DDS, MS, Spear Faculty and Contributing Author

Resources

1. Jung, RE, Sailer, I, Hammerle, CH, Attin, T, Schmidlin, P. In vitro color changes of soft tissues caused by restorative materials. The International Journal of Periodontics and Restorative Dentistry. 2007;27(3):251–257.