Tissue Regeneration on Implantoplasty-Treated Implants Using a Citric Acid–Collagen–Magnesium-Based Solution: An In Vitro and In Vivo Study

Peri-implantitis is an inflammatory disease caused by bacterial colonization that leads to progressive bone loss around dental implants. Implantoplasty is widely used for biofilm removal; however, it alters the titanium surface, generating particle release and impairing surface properties. This study evaluated whether a citric acid-based solution supplemented with collagen and magnesium cations could enhance hard and soft tissue regeneration following implantoplasty. Three surfaces were analyzed: physiological saline (Ctr), 25% citric acid (AC), and citric acid with collagen and magnesium nitrate hexahydrate (AC500/Mg). Surface roughness and wettability were assessed on titanium discs. Cytocompatibility, cell adhesion, and proliferation were evaluated using fibroblasts and osteoblasts up to 21 days, and mineralization was analyzed by alkaline phosphatase. In vivo studies were conducted in New Zealand rabbits with implants placed in the femur and muscle tissue. Surface roughness did not differ among treatments, while wettability significantly increased with citric acid-based solutions. All treatments showed good cytocompatibility. AC500/Mg significantly enhanced cell adhesion, proliferation, and osteoblast mineralization, showing threefold higher activity than controls at 21 days. In vivo, AC500/Mg exhibited greater bone contact (67%) and direct muscle integration, whereas AC and Ctr showed lower bone contact and fibrotic encapsulation. These results indicate that AC500/Mg improves soft and hard tissue responses without altering roughness, suggesting its potential as a regenerative strategy following implantoplasty.