Working postures of dentists and dental hygienists.

A joint study was conducted by a manufacturer of dental stools in the Midwest of the United States and Marquette University to measure the occupational postures of dentists and dental hygienists. The postures of 10 dentists and 10 dental hygienists were assessed using work sampling and video techniques. Postural data of the neck, shoulders and lower back were recorded from video and categorized into 30-degree intervals: o (neutral posture of respective joint), 30, 60 and 90 degrees. Each subject's postures were observed while they were treating patients during a four-hour period, during which 100 observations of postures were recorded at random times. Compared to standing, dentists and dental hygienists were seated 78 percent and 66 percent of the time, respectively. Dentists and dental hygienists flexed their trunk at least 30 degrees more than 50 percent of the time. They flexed their neck at least 30 degrees 85 percent of the time during the four-hour duration, and their shoulders were elevated to the side of their trunk (abducted) at least 30 degrees more half of the time. The postures of the trunk, shoulders, and neck were primarily static. This database of postures can be used by dental professionals and ergonomists to assess the risk dentists and dental hygienists are exposed to musculoskeletal disorders, such as low back pain or shoulder tenosynovitis, from deviated joint postures. They could use these data to select dental furniture or dental devices that promote good body posture, i.e., reduce the magnitude and duration of deviated joint postures, which, in theory, would decrease the risk of musculoskeletal disorders.