Interface-specific functional coatings for soft-tissue integration of craniofacial implants: oral mucosa, percutaneous skin, and muscle

Soft tissue integration (STI) is essential for limiting inflammation, maintaining craniofacial implant stability, and supporting long-term function. This narrative review evaluates functional coatings at three distinct interfaces: oral mucosa around dental abutments, craniofacial muscle and enthesis around temporomandibular joint (TMJ) prostheses, and skin around percutaneous implants. We distinguish direct integrative effects from infection control and immunomodulation, and appraise evidence from cellular responses through tissue-level outcomes. Oral mucosa requires a rapid epithelial and connective-tissue seal under continuous plaque exposure; percutaneous skin requires suppression of epithelial downgrowth and pocket formation across a chronically exposed breach; and muscle-facing temporomandibular joint components require enthesis-like anchorage and load transfer under repetitive motion. The evidence is strongest for cell-level responses and selected preclinical mucosal or skin outcomes, whereas coating-mediated TMJ muscle attachment remains at proof-of-concept stage in non-TMJ models. Negative animal findings further show that favorable cell behavior or added antibacterial activity does not necessarily produce a durable tissue seal. Interface-specific coatings should therefore be designed around a primary tissue-level endpoint, with antimicrobial and immunomodulatory functions treated as supportive and dose-limited.