Which tissue around implants forms a tight seal that limits ingress of bacteria?

• A. Connective tissue
• B. Epithelial tissue
• C. Bone tissue
• D. Salivary layer

Answer: (A)

The key idea is that the soft-tissue barrier around an implant is created by the peri-implant mucosa, with the connective tissue surrounding the implant forming the tight, protective collar that limits bacterial penetration. This dense connective tissue layer, together with its organized collagen fibers, establishes a physical barrier around the implant neck and works with the epithelial attachment to help seal the area. While the epithelial component (junctional epithelium) also contributes to sealing, the surrounding connective tissue is the primary tissue type that forms the robust barrier to ingress of bacteria around implants. The other options don’t provide this surrounding seal at the implant interface—bone is internal and the salivary layer doesn’t constitute the seal at the peri-implant margin.