###### Abstract  
Background: Dental professionals suffer frequently from musculoskeletal disorders (MSD). Dentists and dental assistants work closely with each other in a mutually dependent relationship. To date, MSD in dental assistants have only been marginally investigated and compared to their occurrence in dentists. Therefore, the aim of this study was to compare the prevalence of MSD between dentists and dental assistants by considering occupational factors, physical activity and gender. Methods: This was a cross-sectional observational study. A Germany-wide survey, using a modified version of the Nordic Questionnaire and work-related questions, was applied. In total, 2548 participants took part, of which 389 dentists (240 females and 149 males) and 322 dental assistants (320 females and 2 males) were included in the analysis. Data were collected between May 2018 and May 2019. Differences between the dentists and dental assistants were determined by using the Chi\({}^{2}\) test for nominal and the Wilcoxon-Mann-Whitney U test for both ordinal and non-normally distributed metric data. Results: A greater number of dental assistants reported complaints than dentists in all queried body regions. Significant differences in the most affected body regions (neck, shoulders, wrist/hands, upper back, lower back and feet/ankles) were found for the lifetime prevalence, annual prevalence and weekly prevalence. Data from the occupational factors, physical activity and gender analyses revealed significant differences between dentists and dental assistants. Conclusions: Dental assistants appear to be particularly affected by MSD when compared to dentists. This circumstance can be explained only to a limited extent by differences in gender distribution and occupational habits between the occupations. MSD; dentists; dental assistants; prevalence; occupational factors; physical activity; gender +
Footnote †: journal: Medical  
current evidence that reports that women show a higher prevalence of clinical pain conditions [8; 9; 10]. Furthermore, in the dental profession field, the fact that more women work in this occupational setting should be taken into account. The high proportion of women among dental assistants (99.1% in Germany) is particularly noticeable [11]. In daily practice, dentists and dental assistants work closely together as a team: both work concurrently alongside the patient, working simultaneously in the patient's mouth; thus, their working field is small. Poor visibility and light conditions render the work even more challenging. In this context, unpleasant and unhealthy postures have to be maintained statically throughout a treatment for long periods of time, setting up high physical work demands in this occupational group [4; 12; 13; 14]. [PERSON] et al. [5] have recently demonstrated dependencies between the postures of dentists and dental assistants by using risk scores. It can, therefore, be assumed that the collaborative, mutually dependent work also favors the development of MSD. Consequently, the prevalence of MSD should be considered and analyzed together in dentists and dental assistants. However, MSD in dental assistants have only been marginally investigated worldwide. The single study that has met the criteria of the meta-analysis of [PERSON] et al. [1] for investigating dental assistants evaluated only the 7-day prevalence of MSD in the back (71.9%) and neck (75.0%) [15]. A review by [PERSON] and colleagues from 2010 [4] summarized five studies between 1995 and 2001; this reported the annual prevalence of MSD in the neck and shoulders to be 22.0-62.0% in dental assistants; however, two of the studies examined only 30 [16] and 29 [17] participants. Even less studies have investigated the differences in the occurrence of MSD between dentists and dental assistants. The remaining studies [6; 18] that have met the scientific quality criteria have demonstrated that dental assistants report pain in the knee, leg and foot significantly more often than dentists.