# Evaluation of an Optimized Photobiomodulation Protocol for Accelerated Tooth Movement

## TL;DR

This study shows that adding photobiomodulation (light therapy) to standard orthodontic treatment speeds up tooth movement by about 40%.

## Contribution

The study introduces an optimized photobiomodulation protocol that significantly accelerates orthodontic tooth movement in a randomized pilot trial.

## Key findings

- PBM added to orthodontic force increased monthly space closure by 40% compared to standard force alone.
- The difference in tooth movement rate was statistically significant (p < 0.05) over five months.
- Both digital caliper and 3D software measurements confirmed faster movement in the PBM group.

## Abstract

Introduction

Photobiomodulation (PBM) has a stimulatory effect on periodontal ligament cells involved in bone remodelling and acts synergistically with the applied orthodontic force to accelerate tooth movement and reduce treatment time. This study aims to compare the mean monthly rate of en-masse maxillary extraction-space closure over five months between PBM plus standard orthodontic force and standard force alone.

Material and methods

A randomised, parallel arm, single-blinded pilot study was carried out with control and PBM groups. For all patients after extraction of first bicuspids, a retraction force of 300g per side was applied using a nickel-titanium (NiTi) closed coil spring. Additionally, in the PBM group, PBM irradiation was done at two buccal and two palatal points along the roots for all six maxillary anterior teeth with an 810 nm diode laser (continuous wave (CW), 200 mW, 0.3cm2, 8 sec per spot, four spots per tooth, 6.4J per tooth) on the first, third, seventh, and 14th day from appliance activation day. Thus, appliance activation was done one time per month and four PBMs were done in a month for five consecutive months. The amount of anterior segment retraction and extraction space closure was measured for every patient on the maxillary right and left side at monthly intervals using a digital caliper (Method I) and 3D software (Method II). The collected data were tabulated and statistically analysed using SPSS 25.0 for Windows (IBM Corp., Armonk, NY, USA) and an independent sample t-test was performed (p <0.05).

Results

Comparison of laser versus control first month space closure in mm showed first month (T0-T1) (right side, Method I) (Mean±SD;1.26±-0.105 vs 0.53±0.45); first month (T0-T1) (Right side, Method II) (Mean±SD;1.06±0.15 vs 0.59±0.107). The mean mm rate of en-masse maxillary space closure (on the right and left side) measured by both Method I and Method II across all five months was consistently higher in the laser group compared to the control. The difference in the monthly rate of space closure was statistically significant (p<0.05). Mean differences with 95% CI are reported. The PBM group showed 1.09mm per month extraction space closure compared to 0.7mm per month in the control group. In the patients who received PBM, the tooth movement was 40% faster than in the control group.

Conclusion

PBM added to orthodontic force was associated with a higher monthly rate of extraction space closure. Based on these preliminary results and analysis, the PBM protocol with the new PBM device and the methodology implemented in this randomized pilot study can be replicated for larger trials to check effectiveness in accelerating tooth movement and reducing treatment time.