Progress in Photobiomodulation for Bone Fractures: A Narrative Review

The effect of photobiomodulation therapy on fracture healing: a systematic review and meta-analysis of animal studies

This systematic review and meta-analysis aimed to evaluate the impact of photobiomodulation therapy (PBMT) on fracture healing in animal models. Following PRISMA guidelines, an electronic search was conducted in PubMed/MEDLINE, Scopus, Embase, and Web of Science databases without date or language restrictions. Animal studies evaluating the effect of PBMT on the healing of complete fractures were included. SYRCLE's risk of bias assessment tool was used for quality appraisal. Meta-analysis and sensitivity analysis were performed for selected outcome measures using Stata version 16, with a significance level of 0.05. Of 1,656 studies, 27 met eligibility criteria. Rabbits and rats were used in 17 and 10 studies, respectively. The tibia was the most common site of fracture, followed by the femur, mandible, and radius. The most frequently used emitters were 780 nm LASER, followed by 808 nm and 830 nm LASER. LEDs were used in comparison to LASERs in three studies and solely in one study. The most frequent energy density and power density were 4 J/cm2 and 100 mW/cm2, respectively. Radiography, histology, mechanical testing, and spectroscopy were the most common assessment methods of fracture healing. While most studies reported PBMT's positive effect on fracture healing, meta-analysis found no significant impact on maximum fracture force or Raman peaks of hydroxyapatite, indicating no significant influence on mineralization (P > 0.05). Although PBMT shows potential for enhancing fracture healing in animal models, meta-analysis showed that it has no effect on maximum force of fracture or Raman peaks of hydroxyapatite. Registration: The protocol of this systematic review was registered on PROSPERO with the ID CRD42024514398.

Effect of Photobiomodulation Therapy on Peri-Implant Bone Healing in Extra-Short Implants in a Rabbit Model: A Pilot Study

Objective: To evaluate the effects of photobiomodulation therapy (PBMT) at distinct energy levels on peri-implant bone healing in extra-short implants in a experimental rabbit model. Background: The effect of PBMT on peri-implant bone healing in short implants remains unclear. This explored the effect of PBMT on extra-short implants in terms of bone-implant contact (BIC) length and rate, and implant stability quotient (ISQ). Methods: Fifteen white New Zealand rabbits were randomly divided into five groups. In all groups, extra-short implants (3.5 × 4 mm; Nucleoss T6, İzmir/Turkey) were placed in both tibias of the rabbits. PBMT was performed in four groups (group 1, 5 J/cm2; group 2, 10 J/cm2; group 3, 20 J/cm2; and group 4, 25 J/cm2); no PBMT was performed in the control group. On the 30th day, the rabbits were sacrificed and peri-implant tissue samples were obtained to determine the BIC length and BIC rate. Implant stability levels were measured by resonance frequency analysis using the Osstell penguin device and were determined as ISQ values on the 1st and 30th days of the study. Results: PBMT significantly increased the BIC length and BIC rate in groups 3 and 4 (p < 0.001). For the ISQ values, there were significant differences between the 1st and 30th day (p < 0.001). On the 30th day, the ISQ values were significantly higher in groups 3 and 4 compared with the remaining groups (p < 0.001). Conclusions: In this study, PBMT improved peri-implant bone healing through increase in BIC length, BIC rate, and ISQ parameter values in extra-short implants.