Introduction: In the scientific literature, a number of studies have reported conflicting results regarding the effects of occlusal vertical dimension (OVD) on sports-related skills. The purpose of this study was to increase OVD in sports subjects so as to specifically investigate the influence on cervical spine mobility. In particular, we measured cervical range of motion (ROM) before and after increasing OVD in individuals, either with or without malocclusion, analyzing both sports and sedentary subjects.

Materials and methods: Participants were divided into two groups: a sports group (SG) and a control group (CG), each including 18 subjects. The SG was composed of sports subjects (age: 20.11±3.45 yrs; BMI: 25.39±2.32 kg/m2), whereas the CG consisted of age-matched sedentary subjects (age: 25.78±2.26 yrs; BMI: 24.88±2.87 kg/m2). Cervical range of motion (ROM) was evaluated, by way of an accelerometer (Moover®, Sensor Medica®), before (pre-test) and after (post-test) increasing OVD.

Results: The main finding of this study was that sports subjects showed no significant difference, compared to control subjects, in cervical ROM in response to increased OVD. Moreover, we found that sports and sedentary subjects alike showed no significant change in cervical spine mobility as a result of increased OVD, regardless of whether they were affected by malocclusion (class II) or represented subjects with normocclusion (class I).

Conclusion: In accord with several studies reported in the literature, the findings of our study indicate that occlusal splints failed to significantly improve the physical-performance endpoint measured, i.e. cervical ROM, in sports subjects as compared to sedentary individuals. Due to the paucity of studies, characterized by conflicting results, there is as yet no compelling scientific evidence as to whether OVD positively impacts sports performance or not. Accordingly, we suggest that further scientific investigation, regarding the relationship between sports performance and OVD, be conducted in the field of sport and exercise sciences.