Ergonomics evaluation of technology change and its effects on health - case study : proprioceptive derivation (Pd) in Thailand

Sammanfattning: Musculoskeletal disorders are common among dentists as indicated in many studies. In Thailand, a new technology called proprioceptive derivation (Pd) was introduced to dentists as a concept to reduce musculoskeletal disorders and improve working situation. The new technology (soft-wear and hard-wear) has changed both the working method as well as working equipment. Instead of a tilted dental chair and adjustable lamp the new concept consists of equipments designed with dental bed and fixed lamp. The dentists use proprioceptive self-awareness to determine their postures, movements and process of dental procedure. Study I: The aims of this study were to assess the working conditions and the attitude among experienced users of the new technology, the Pd concept. 12 dentists participated in this study. The results showed that the dentists have been working 5.02 ± 8.07 years, and have experiences working with Pd concept for 19.67 ± 11.3 months, the average working hours/day was 5.42 ± 1.16 hours, and average number of patients/day was 8.5. Only five dentists reported that they have pauses between the patients; the average breaking time was 5 minutes. Most of the dentists perceived dental work as a physical demanded job, and felt exhausted at the end of the day after work.Time spent in each dental work task was varied from 3 to 60 minutes. They had low score in stress level of ‘Solving problem in patients with physical limitation' item. Most of them liked the Pd concept because they experienced that the concept could reduced physical muscular stress, enhance accuracy of treatment and communication with patients, reduce treatment time, and provide better infection control. Two dentists did not like the concept because it could not cover all dental tasks/treatment, and it was difficult and complex. Study II: The aims of this study were: to analyse working posture of dentists working traditionally with the old technology and with the new technology, according to the Pd concept and to determine the prevalence of musculoskeletal discomfort in the two groups of dentists. The participants were 12 dentists working with Pd concept, and 10 dentists working with traditional concept. The results showed that all dentists from both groups used a sit-down posture together with a four-hand technique. There was a different in sitting posture and clock-related working position among the two groups; 100% of dentist working according to Pd concept worked at 12 o'clock position and were sitting in a posture of straight low and upper back, the neck bent, the seat straight. Most dentists working traditionally worked at 10o' clock position and in a posture of straight low and upper back, the neck bent. The dentists working with the Pd concept still have the discomfort in neck and shoulder region as the dentists working traditionally. However, they have lower rate of musculoskeletal discomfort in low back region than in the traditional group. From these studies, it is possible to conclude that the new technology, the Pd concept could made it possible for the dentists to adopt a more upright sitting working posture, reduce times in some dental work tasks, and reduce stress in working situation. However, the Pd concept could reduce only musculoskeletal discomfort in low back region among the dentists, and they still have the discomfort in neck and shoulder regions. Not all the dentists liked working with the new technology. Perhaps this new technology is not appropriate for all dentists and all dental work tasks.