Biomodulation effects induced by ultrasound stimulation in periodontal cells implicated in orthodontic tooth movement: A systematic review

Accelerating orthodontic tooth movement (OTM) is increasingly important for shorter treatment times, which reduces periodontal risks, root resorption and dental caries. Techniques to accelerate OTM focus on stimulating bone remodelling by enhancing osteoclast and osteoblast activity and include both surgical and non-surgical methods. The therapeutic potential of ultrasounds is highly recognized among many medical areas and has shown promising results in modulating bone remodelling and inflammation phenomena. This systematic review aims to collect and analyse the current scientific in vitro and ex vivo evidence on ultrasound stimulation (US) bioeffects in cells implicated in tooth movement. This review was conducted according to PRISMA 2020 guidelines. A bibliographic search was carried out in the PubMed, Scopus and Web of Science databases. Sixteen articles were selected and included in this review. The revised studies suggest that US of 1.0 and 1.5 MHz, delivered at 30 mW/cm2, 10 to 30 min daily over three to 14 days seems to be effective in promoting osteoclastogenic activity, while US of 1.5 MHz, 30 to 90 mW/cm2, in 5- to 20-min sessions delivered daily for 5 to 14 days exhibits the potential to stimulate osteogenic activity and differentiation. Previous research yielded varied evidence of the effectiveness of US in orthodontics. Future animal studies should employ the recommended US parameters and investigate how distinct protocols can differentially impact tissue remodelling pathways. The knowledge arising from this review will ultimately potentiate the application of US to accelerate OTM in the clinical setting.