Influence of the width of keratinized tissue on the development and resolution of experimental peri-implant mucositis lesions in humans.

Objectives: To analyze the influence of the width of keratinized mucosa (KM) on the development and resolution of experimental peri-implant mucositis lesions at abutments with different microstructures in humans.

Material And Methods: In a randomized, controlled study, a total of 28 patients had received 28 target implants exhibiting a KM ≥2 mm. These were randomly connected with either partially microgrooved- (test) (n = 15) or machined (control) (n = 13) healing abutments. The study protocol included a wound healing period (WH) following implant placement (12 weeks), a plaque exposure phase (EP) of 21 days (EPd21) and a resolution phase (RP) including visits at 2, 4, and 16 weeks (RPw2; RPw4; RPw16) following plaque removal. Linear regression analyses were used to analyze the relationship between the width of KM and clinical outcomes (i.e., modified plaque index [mPI], modified gingival index [mGI], bleeding on probing [BOP], and probing depth [PD]).

Results: Mean and median KM values (end of WH) were 5.9 ± 2.6 and 5.0 mm (min: 2 mm; max: 10 mm; interquartile range: 5 mm) at test- and 5.5 ± 2.6 and 4.0 mm (min: 3 mm; max: 11 mm interquartile range: 4 mm) at control abutments. The linear regression analysis revealed significant correlations between the width of KM and mPI (test: RPw2; control: RPw16), mGI (test: RPw16), BOP (both: RPw16), and PD (test: RPw16; control: EPd21, RPw2, RPw4, RPw16) scores.

Conclusion: The width of KM (≥2 mm) had some effects on the development (i.e., at 21 days) and resolution of experimental peri-implant mucositis lesions at both abutment types.