Effect of Tool Design on Hand Pain in Dental Practitioners

This is a randomized controlled trial to evaluate the effects of a new dental tool handle design on hand and arm symptoms among dentists and dental hygienists who perform dental scaling. This will be a 4 month intervention in the practitioner's workplace. The study may identify a tool handle design that reduces the risk for developing upper extremity occupational musculoskeletal disorders (e.g., carpal tunnel syndrome) among dentists and dental hygienists.

The specific aims of the project are to determine whether hand/wrist, forearm/elbow and shoulder symptoms (e.g., pain, fatigue, paresthesias) and hand function are less severe among dentists and dental hygienists who use a new dental tool in comparison to those who use a more conventional tool for performing scaling. One hundred twenty (120) subjects will be randomized to use one of 2 handle designs for a 4 month period and during this time will perform their usual dental scaling work with the new tools. The effects on outcome measures will be adjusted for potential covariates (e.g., age, gender, hours scaling per week, etc.). The primary null hypothesis is: there is no difference in change in pain severity between subjects who use a new tool in comparison to those who use a conventional tool.

RESEARCH DESIGN AND METHODS

In this study, 120 participating dentists and dental hygienists will be randomized to receive one of 2 scaling tools and will use the tools for 3 months while performing their usual dental scaling work. Randomization will be at the level of the clinic to avoid participant contamination. Participants will complete a weekly questionnaire to assess symptom severity. The data analysis will use an intention-to-treat approach and will control for important covariates.

Interventions Based on the pilot data, the investigators have selected 2 tool handle designs that are similar to conventional tools but have features that exploit the differences identified in our preliminary data. The dependent measures of pinch force and muscle activity were most sensitive to diameter, followed by weight, followed by shape. The tool characteristics selected for this proposal are based on the data from the laboratory studies presented in the Preliminary Studies section and the Appendix (Dong et al., JADA, 2006; Dong et al., Appl Ergo, 2007). The tool parameters were selected to provide the greatest difference in peak pinch force, yet be as close as possible to the look and feel of a conventional instrument. Half of the participants will be provided with Tool 1 and half with Tool 2. Tool 1 is the closest to a conventional tool in diameter and weight while Tool 2 has a larger diameter and is lighter. The differences and similarities between Tools 1 and 2 are listed below.