Dentogingival complex and biologic width
- The biological width is determined by the keratinized oral epithelium, the peri-implant junctional epithelium, and the sub-epithelial connective tissue.
- Gingiva and peri-implant mucosa differ in composition of cells, fibers, collagen, and vessels.
Differences between peri-implant mucosa and gingiva
The peri-implant mucosa consists of an externally located keratinized oral epithelium, which is connected to the peri-implant junctional epithelium facing the abutment. The latter extends approximately 2 mm apical to the coronal soft tissue margin, still being 1.0 –1.5 mm away from the peri-implant bone crest.
The biological width differs between implants and teeth, being >0.5 mm greater around implants (3.8 vs 3.2 mm), which is mainly due to the greater height of the interposed connective tissue.
Figure 1: Accidental mucosal perforation of a submerged implant. This will frequently result in marginal bone resorption, assumingly aiming to adjust the biological width.
Compared to teeth, the supra-crestal connective tissue around implants contains fewer fibroblasts but more collagen fibers. In close vicinity to the implant/abutment surface, marginal bone attached collagen fibers run parallel to the implant/abutment surface. Fibers in gingiva around teeth are mainly circular and root cementum attached with a different orientation than around implants.
There are less vascular structures in the supra-crestal connective tissue near the implant compared to the same location around teeth.
The composition of cells, fibers, collagen, and vessels makes the peri-implant connective tissue more comparable to a scar tissue.
Substantial data support that implants of different materials (e.g titanium and zirconia) and of various roughness show a similar composition pattern, however with minor deviations.