Investigating the Effects of Smartphone Use on the Masseter Muscle

The aim of this study was to determine the short- and long-term effects of smartphone use on the masseter muscle. In the short term, to investigate whether repetitive thumb movements during phone use will cause a spontaneous muscle activation and/or tenderness in the masseter muscle; in the long term, to investigate the relationship between strength change and tenderness of the tenar and masseter muscles depending on the intensity and duration of phone use.