## 1 Introduction  
Dentists (Ds) and dental assistants (DAs) are exposed to several risk factors for developing musculoskeletal disorders (MSDs) due to their occupational demands, such as prolonged static postures, repetitive movements, instrument vibration, poor lighting conditions, poor and awkward positioning of the dental health professionals (DHPs) when working on the patients or the poor positioning of the patients [1]. A high prevalence of MSDs in dental personnel has been demonstrated in several international studies over many years [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18]. The regions of the neck, shoulder and back are the most affected [3, 4, 19]. In previous studies with Ds and DAs in Germany [3, 4], 96.1% of Ds and 98.5% of DAs reported a lifetime prevalence, 92.8% of Ds and 97.5% of DAs a 12-month prevalence and 66.8% of Ds and 86.9% of DAs a 7-day prevalence of MSDs.  
DHPs, like other healthcare professionals (HCPs), play an important role in society by maintaining the health of others. The importance of this task may mean that Ds and DAs do not wish to, or cannot easily, interrupt their work. Ds, in particular, not only have a responsibility in their medical work towards the patient, but also an economic responsibility in the context of a managerial function or ownership of a practice towards the staff. This leads to the assumption that the interruption of dental work is not desirable, which may, thus, predispose Ds and DAs to increased work injuries such as MSDs [2].  
In order to be able to continue working despite complaints, painkillers, among other things, are taken to alleviate or suppress illness-related complaints [2; 20]. The use of alcohol and other drugs are also used in this regard [21]. It is estimated that around 10.0-15.0% of all HCPs misuse drugs or alcohol at some point in their career [20]; 6.0-8.0% of HCPs have a substance use disorder while up to 14.0% have an alcohol use disorder [20]. Overall, there are few studies, internationally, that examine substance use in HCPs. This may partly be due to the fact that it is a topic that HCPs do not wish to talk about. However, this also means that the figures from studies carried out are probably higher in reality due to underreporting.  
The present study is part of a research project on the optimisation of ergonomics in dentistry (German abbrev.: SOPEZ) [22]. As part of this large study, the highest lifetime prevalence of MSDs was found at the neck (Ds: 79.4%, DAs: 90.9%), followed by the shoulder (Ds: 66.8%, DAs: 80.0%), lower back (Ds: 58.6%, DAs: 68.7%) and upper back (Ds: 42.9%, DAs: 56.9%) regions [3; 4].  
In this context, the question arises whether, in Germany, these complaints are treated with medication in order to continue achieving professional performance and to ensure the supply of health care. Therefore, the aim of the present study was threefold: (1) to survey the choice of drug therapy among Ds and DAs, as well as (2) the substrates and (3) the frequency of intake. The hypotheses to be tested are:  
1. Both dentists and dental assistants take pain medication to reduce MSD.
2. There is no difference in the amount of medication intake between dentists and dental assistants.
3. There is no difference in the frequency of medication intake between dentists and dental assistants.