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

Abstract 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.