Statement of problem: The primary function of the periodontal tissues, besides attaching the tooth to the jaw, is gingival protection; that is, to provide a seal against the contaminated environment of the oral cavity. Detailed data regarding protection of the periimplant mucosa in patients with transmucosal implants are lacking.
Purpose: The purpose of this histological study was to demonstrate the structural and ultrastructural features of the interface between transmucosal titanium implants with oxidized, machined, and acid-etched surfaces and surrounding tissues by combined light and electron microscopy.
Material and methods: Five patients received 12 experimental titanium, 1-piece mini-implants with an oxidized, acid-etched, or machined surface distal to conventional implants. Following transmucosal healing of 8 weeks and at the abutment connection of the regular implants, the mini-implants were removed with a layer of surrounding hard and soft tissue. The specimens were fixed and processed for light, transmission electron, and scanning electron microscopy.
Results: For all 3 types of surfaces, substantial structural analogies were demonstrated between gingiva and periimplant mucosa in humans, both shown to provide protection for the underlying soft tissues and alveolar bone. Depending on the implant surface texture, substantial differences were noted in the manner the implants interface with connective tissue.
Conclusions: The mechanisms of protection in the periimplant mucosa correspond to those in the gingiva surrounding a tooth. The surface texture of implants may affect the orientation of collagen fibers of the connective tissue at the implant surface.