Histological evaluation of the soft tissue response to plasma-activated healing abutments: A prospective controlled...

This prospective clinical trial aimed to histologically evaluate peri-implant soft tissue response to healing abutments treated with a vacuum plasma reactor.

Thirty bone-level implants were placed with machined healing abutments designed to be retrieved using a calibrated mucotome after soft-tissue healing. Test abutments were plasma-activated immediately before placement, whereas control abutments were left untreated. After 3 months, plaque index and bleeding on probing were recorded prior to collecting peri-implant soft-tissue biopsies. The specimens were processed and evaluated clinically and histologically.

Thirty patients with 30 implants completed the study. Histological evaluation showed lower inflammation scores in the basal zone around plasma-activated abutments (P = 0.04). Mean inflammation scores in the test group were 2.78 ± 0.7, 2.52 ± 0.5, and 1.72 ± 0.5 in the upper, intermediate, and basal zones, respectively, compared with 3.28 ± 0.8, 2.93 ± 0.6 and 2.36 ± 0.5 in controls. Connective-tissue maturation and epithelial regeneration were comparable between groups (approximately 3.1 and 3.0, respectively). Vascularization was slightly higher in the test group (1.20 ± 0.19 vs. 1.09 ± 0.05). The cornified layer contacting the abutment was significantly thicker in the test group (2.89 ± 0.8 vs. 1.91 ± 0.7, P = 0.008). No significant differences were observed for plaque index, whereas bleeding on probing was lower in the test group.

Plasma-activated healing abutments were associated with localized histological differences at the epithelial-abutment interface, particularly in basal inflammation and cornified layer thickness, while most parameters remained comparable between groups.