Photobiomodulation in Dental Implant Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background/Objectives: Photobiomodulation (PBM) is proposed to enhance osseointegration, improve stability, reduce marginal bone loss, and alleviate pain in implant dentistry. Since clinical outcomes remain heterogeneous, this systematic review and meta-analysis evaluated PBM's effects as an adjunct to implant therapy, focusing on stability, peri-implant bone outcomes, and pain. Methods: A comprehensive search of six databases and gray literature (June 2024-May 2025) followed PRISMA guidelines (PROSPERO: CRD420251041607). We included randomized controlled trials (RCTs) evaluating PBM against sham or no-PBM controls in adults. Risk of bias was assessed using RoB 2, and data were synthesized via random-effects meta-analyses with GRADE certainty assessments. Results: Thirty-two RCTs (829 patients, 1278 implants) were included. Postoperative pain was consistently reduced by PBM (MD = -0.27; 95% CI -0.35 to -0.19). For stability, Periotest favored PBM (MD = -0.55; 95% CI -0.84 to -0.27), indicating a transient early improvement. Similarly, resonance frequency analysis (ISQ) demonstrated a statistically significant improvement favoring the PBM group (MD = 1.26; 95% CI 0.61 to 1.91, p < 0.001), indicating a statistically significant increase in early implant stability. Marginal bone loss showed a statistically significant but clinically small reduction favoring PBM (MD = -0.09 mm; 95% CI -0.16 to -0.01). For peri-implant bone density, time-stratified models showed that PBM promoted a robust, significant initial benefit in 3D CBCT Hounsfield Units at baseline (MD = 114.07 HU, p = 0.01; overall MD = 86.02 HU, p = 0.14), while conventional 2D radiographic grayscale measurements captured a modest but statistically significant overall benefit (MD = 9.82, p = 0.03), showing a positive long-term trend up to 6 months (MD = 24.19, p = 0.04). Conclusions: PBM represents a promising supportive intervention in dental implant surgery, consistently reducing postoperative pain, enhancing early functional and structural stability, and promoting early bone mineralization. However, as the overall certainty of evidence according to the GRADE framework ranges from low to very low, these findings must be interpreted with caution due to substantial chronological and methodological heterogeneity across protocols.