Timing of keratinized mucosa augmentation and peri-implant outcomes: A systematic review and meta-analysis.

Purpose: This study aimed to compare different surgical timings for keratinized mucosa (KM) augmentation and assess the impact on peri-implant parameters stability.

Methods: Electronic searches were conducted through MEDLINE (via PubMed), Scopus, Embase, and Web of Science up to June 13, 2024, which was completed with a manual search. The inclusion criteria focused on randomized and non-randomized human clinical studies that assessed outcomes of KM augmentation, with at least 3-months follow-up. The analysis included changes in KM width over time and several secondary outcomes.

Results: Twenty-five studies satisfied the inclusion criteria. The studies included 855 patients and 1588 implants. The KM width significantly increased after surgery, regardless of the time or method of intervention (MD: 5.17, 95% CI: 4.59, 5.75, p<0.001). The second-stage surgery, particularly with the use of autogenous graft, indicated the lowest reduction in KM width up to 3 months after surgery, while a significant shrinkage was found when the augmentation was performed post-restoratively.

Conclusion: The evidence suggests that second-stage surgery is acceptable for KM augmentation, whereas the post-restorative phase is generally not the primary option. In cases where suboptimal soft tissue conditions are detected, it is advisable to either undertake KM augmentation or refer the patient for additional assessment before proceeding with the delivery of the restoration. Due to limited data, it is not possible to come to a definitive conclusion about the other surgical phases.