Motion analysis in the field of dentistry: a kinematic comparison of dentists and orthodontists

OBJECTIVES To conduct a kinematic comparison of occupational posture in orthodontists and dentists in their workplace. DESIGN Observational study. SETTING Dentist surgeries and departments of orthodontics at university medical centres in Germany. PARTICIPANTS A representative sample of 21 (10 female, 11 male) dentists (group G1) and 21 (13 female, 8 male) orthodontists (G2) with one male dropout in G2. OUTCOME MEASURES The CUELA (computer-assisted acquisition and long-term analysis of musculoskeletal loads) system was used to analyse occupational posture. Parallel to the recording through the CUELA system, a software-supported analysis of the activities performed (I: treatment; II: office; III: other activities) was carried out. In line with ergonomic standards the measured body angles are categorised into neutral, moderate and awkward postures. Activities between the aforementioned groups are compared using the stratified van Elteren U test and the Wilcoxon-Mann-Whitney U test. All p values are subject to the Bonferroni-Holm correction. The level of significance is set at 5%. RESULTS The percentage of time spent on activities in categories I-II-III was as follows: dentists 41%-23%-36% and orthodontists 28%-37%-35%. The posture analysis of both groups showed, for all percentiles (P5-95), angle values primarily in the neutral or moderate range. However, depending on the activity performed, between 5% and 25% of working hours were spent in unfavourable postures, especially in the head-and-neck area. Orthodontists have a greater tendency than dentists to perform treatment activities with the head and torso in unfavourable positions. The statistically significant differences between the two groups with regard to the duration and the relevance of the activities performed confirm this assumption for all three categories (p<0.01, p<0.05). CONCLUSIONS Generally, both groups perform treatment activities in postures that are in the neutral or medium range; however, dentists had slightly more unfavourable postures during treatment for a greater share of their work day.