24 January 2023

---

Integration of peri-implant soft tissue to abutments

Lara Figini

---

Peri-implant soft tissue integration remains critical to the long-term success of implant therapy.

The formation of an early and long-lasting barrier to protect peri-implant structures is essential to avoid bacterial penetration which could jeopardize initial healing and long-term implant success.

The peri-implant soft tissue interface between the junctional epithelium and the titanium surface has been shown to be achieved via hemidesmosomes. On the other hand, the connective tissue interface consists of tissue with poor cells and vascular structures, rich in collagen fibers similar to scar tissue.

These collagen fibers are parallel to the titanium, whereas in natural teeth they show a strong and perpendicular anchorage to the dentine surface through the Sharpey fibers.

The physicochemical composition of the abutment appears to be an important factor for peri-implant soft tissue integration when using a flat-to-plate abutment-implant connection.

In vitro results have shown that the adhesion and spreading of epithelial cells are good on metal surfaces, such as titanium and gold alloys, especially if the surface is smooth.

Materials and methods

In an in vitro study, published in the Journal of Prosthodontics in March 2022, the authors evaluated the integration of soft tissues with four different transgingival materials, as well as peri-implant bone remodeling, in pigs.

Clinicians placed a total of 40 implants in five piglets in one stage surgery, and two of each of the following abutment materials were used in each animal:

• titanium (control group)
• polymethyl methacrylate (PMMA)
• zirconia (Zi)
• veneering ceramic (VC).

After a three-month healing period, specimens were collected and subjected to non-decalcified histology. The soft tissue dimensions (sulcus, junctional epithelium, and connective tissue attachment) were evaluated on each abutment, and the distance from the implant margin to the first bone-to-implant contact (BIC) was measured.

Results

The mean biological width, characterized by the sum of the junctional epithelium and connective tissue measurements, was 3.8 (0.6) mm and no statistically significant difference was found between the four groups (p = 0, 41).

However, a long (3.3-3.8 mm) junctional epithelium and a very short (0.1-0.2 mm) connective tissue attachment were observed with all stumps.

Peri-implant bone remodeling was similar in all four groups (p = 0.88).

Conclusions

From the data of this study, researchers concluded that the four transgingival biomaterials tested offer peri-implant soft tissue integration and tissue remodeling comparable to each other, consisting of a long junctional epithelium extending close to the bone level and a rather short portion of connective tissue.

For more information: "The Effects of Abutment Materials on Peri-Implant Soft Tissue Integration: A Study in Minipigs."