Quantitative Optimization, Standardization and Individualization of Photobiomodulation Delivery in Dentistry: Photobiomodulation Pre-emptive Dental Anaesthesia Delivered by Neodymium: Yttrium Aluminium Garnet (Nd:YAG) Photons

Abstract

Photobiomodulation (PBM) is the delivery of therapeutic photons through teeth and periodontium non-surgically to the underlying targets to induce anaesthesia, anti-inflammation and regeneration, as a holistic alternative to conventional Dentistry. Evidence supports PBM-Nd:YAG photons as a clinically effective and safe means of anaesthesia. However, correlation between the delivered photons and different thicknesses of tooth, pulp and periodontium, has not been previously quantified in a standardized manner, which is relevant to the optimization of its effectiveness. Photometric and spectrophotometric studies showed an increase in transmitted photons through the tooth to the pulp that correlated with decreased tooth thickness, increased power and wavelength and in pulsed delivery; an increase in transmitted PBM photons through the human pulp correlated with increased wavelength and decreased pulpal thickness. I designed, built and validated a mini-photodetector and showed a strong correlation between attenuated and transmitted Nd:YAG photons and periodontal thickness in vivo. Using these findings and dental radiographic imaging, it is clinically practical to quantify individual tissue thickness and individualize delivery to the PBM target. In a placebo-controlled clinical trial, Nd:YAG photons at dose based on the defined quantitative correlations resulted in clinically significant reduction in pain during mucosal needle injections, comparable to conventional Xylocaine topical anaesthetic. Similarly, GaAlAs photons at dose delivered in pulse mode were significantly effective in reducing orthodontic pain and root-resorption in a placebo-controlled trial. PBM-Nd:YAG photons equivalent to the clinical anaesthetic dose, showed an intrapulpal temperature rise < 3oC well within the thermal safety window in an ex vivo quantitative temperature study; and did not damage the neuronal cells, and showed a significant reduction in axonal mitochondrial membrane potentials and mitochondrial movement consistent with inhibition of fast axonal flow and a conduction block in a rat-DRG cell cultures study. Quantitative standardizing, optimizing and individualizing of PBM delivery in Dentistry may impactfully change the acceptance and use of PBM to combat the global challenges in oral health.