Impact of Glycine Powder Air-Abrasive Debridement on Peri-Implant Mucositis: A Randomized Control Trial of Clinical, Microbial, and Immunological Changes

Aim Peri-implant mucositis, a dysbiosis-driven inflammatory disease, is a precursor to peri-implantitis, underscoring the need for early disease management. Therefore, we investigated the efficacy of glycine powder in resolving clinical inflammation and restoring host-microbial homeostasis. Methods Thirty subjects were randomized to receive either glycine powder air-abrasive debridement or ultrasonic instrumentation. Clinical parameters (probe depth [PD], modified Sulcular Bleeding Index [mSBI], modified Plaque Index [mPlI]), biofilm and peri-implant crevicular fluid were collected at baseline and at 1-day, 1-, 3-, 6-weeks and 3- and 6-months post-therapy. Microbial recolonization was examined using 16S rDNA sequencing and immune response was semi-quantified using a bead-based 17-plex microarray. Results At 6-months, both groups demonstrated non-significant reductions in mSBI when compared to baseline (p > 0.05, Wald test, mixed model for repeated measures). However, mSBI and PD decreased in the test group from week-1 to 3-months, while control group decreased at 1- and 3-weeks only. mSBI was lower in the test group when compared to controls from Week-1 to 3-months, while PD differed between groups at 6 weeks and 3-months. Glycine group demonstrated significant microbial shifts after 24-h, increases in species richness and health-compatible species, and loss of pathobionts (p < 0.001, Dunn test). Pro-inflammatory cytokines decreased from 1- to 6-weeks or 3-months (p < 0.05, Wald test). Comparable results were obtained in the ultrasonic group at 3-weeks and sustained over 6-weeks post-therapy. Conclusions Glycine therapy leads to early and sustained change in host-microbial interactions when compared to ultrasonics, however, the changes wrought by both therapies were sustained for a maximum of 3 months.