# Hand Joint Hypermobility among Dental Students--A Cross-Sectional Study
## 4 Discussion
### High Prevalence of Hand Joint Hypermobility among a Cohort of Dental Students  
The prevalence of generalized joint hypermobility in the literature is 2-65%. This broad range may be due to different age groups and ethnicities of the included individuals, as well as various scoring systems and cut-off criteria [11; 23; 24]. The majority of these studies adopted the Beighton [21; 25] or the Brighton criteria [26], with prevalence rates in university students ranging from 20% when the Brighton scale was utilized [27] to 26% with a cut-off Beighton score of \(\geq\)5 [27] and approximately 40% with a cut-off Beighton score of \(\geq\)4 [28]. Specifically, studies that investigated the prevalence of localized joint hypermobility among university students have identified rates ranging between 22% and 58% [4; 8; 9]. However, one of these studies specifically involved volunteers from physiotherapy and medical courses, which could lead to overrepresentation and potentially result in an overestimation of the prevalence of hypermobility [8]. Another study was conducted on individuals attending a music school [9], a category that has been speculated to have a higher risk [29]. Conversely, a single study assessed the prevalence of peripheral hand joint hypermobility in a similar sample population [4]. This research was conducted on 319 dental students across five years of dental school, divided into different ethnic and age groups for an analysis [4]. The findings of this study revealed that Taiwanese individuals displayed a higher prevalence of peripheral joint hypermobility, with 29.0% of them exhibiting a severe form while 25.8% exhibited a moderate form. On the other hand, Arab students were the second most common group to present with moderate hypermobility, which was observed in 40.0% of them. It is important to note that this investigation utilized different assessment tools to identify hypermobility compared to our present study, namely the Beighton scale with a cut-off of 4 and the Brighton criteria with a minimum of two major criteria or one major and two minor criteria. As a result, this study examined hyperextension of the elbow, knee, trunk, and palms of the hands resting on the floor, which were not evaluated in our study. Additionally, this study did not explicitly exclude subjects diagnosed with a generalized hypermobility syndrome. Consequently, the results obtained from this study may not be directly comparable with our findings. The current study revealed a worrisome prevalence rate of peripheral hand joint hypermobility among a cohort of first-year dental students. As many as 15% and 16% of them had a high and moderate risk of hand joint hypermobility, respectively. This is a concerning number, considering that a higher degree of hypermobility has been associated with the development of musculoskeletal complaints in longitudinal and cross-sectional studies [30; 31]. This risk factor further contributes to the already elevated prevalence of musculoskeletal disorders among dental professionals, which accounts for as high as 98% [32; 33; 34; 35]. One other potential musculoskeletal condition is the development of osteoarthritis. Complaints of osteoarthritis in one's hands have been specifically associated with an increased laxity at the thumb MP joint [36; 37]. In our study, a greater hypermobility at the thumb joints was detected in a minority of the students. Conversely, the greatest degree of hypermobility was most commonly observed in the middle and ring fingers of both hands. This is in contrast to other studies that have identified the small finger and the thumb as the fingers with more severe hypermobility [7; 38]. However, these studies were not conducted on a dental student population. Our finding of the middle and ring finger joints being the most affected is noteworthy for the field of dentistry, considering that these fingers constitute the finger rest for the majority of the hand grip position during dental procedures (e.g., pen grasp and modified pen grasp) [39].