The effects of dental hygiene instrument handles on muscle activity production

The objective of this study was to compare the effects of 10 commercially available instrument handle designs' mass and diameter on forearm muscle activity during a simulated periodontal scaling experience.

A convenience sample of 25 registered dental hygienists was recruited for this IRB-approved study. Ten commercially available instruments were categorized into four groups based on their masses and diameters: large diameter/light mass, small diameter/light mass, large diameter/heavy mass and small diameter/heavy mass. Participants were randomized to four instruments, one from each group. Participants scaled with each instrument in a simulated oral environment while muscle activity was collected using surface electromyography. Muscle activity was compared among the four instrument group types.

Muscle activity of the flexor digitorum superficialis was not significantly influenced by instrument mass (p = 0.60) or diameter (p = 0.15). Flexor pollicis longus muscle activity was not significantly influenced by instrument mass (p = 0.81); diameter had a significant effect (p = 0.001), with smaller diameter instruments producing more muscle activity. For the extensor digitorum communis and extensor carpi radialis brevis, instrument mass did not significantly affect muscle activity (p = 0.64, p = 0.43), while diameter narrowly failed to reach significance for both muscles (p = 0.08, p = 0.08); muscle activity for both muscles increased with smaller diameter instruments.

Results from this study indicate instrument diameter is more influential than mass on muscle activity generation; small diameter instruments increased muscle activity generation when compared to large diameter instruments. Future research in real-world settings is needed to determine the clinical impact of these findings.