The aim of this study was to clarify the relationship between the landing position during consecutive straight jumps and standing posture stability of trampoline gymnasts with stable occlusal balance. Participants were 10 healthy men (BMI: 18.5–25.0) and 10 trampoline gymnasts (competition experience: ≥12 years), all of whom had stable occlusal balance. To assess postural control function, the displacements in the forward–backward (COP-FB) and the left–right directions (COP-LR) of the center of foot pressure were recorded under eyes-open and eyes-closed conditions. For the trampoline gymnasts, landing positions during 10 consecutive straight jumps were recorded. The horizontal displacements from the center of the bed in the forward–backward (H-FB) and the left–right directions (H-LR) directions were recorded. Differences in COP displacement between participant groups and between visual conditions were analyzed, along with the correlations between COP displacement and landing position. COP-FB in the eyes-open condition was significantly smaller in trampoline gymnasts than in healthy men (p < 0.05). Significant strong positive correlations were observed between COP-FB and H-FB, and between COP-LR and H-LR (p < 0.05). The postural control function of trampoline gymnasts was superior to that of healthy men in the eyes-open condition. The landing position during straight jumps of trampoline gymnasts with stable occlusal balance reflects standing postural control function.

The aim of this study was to clarify the effect on the postural control function of equalizing the occlusal contact state by wearing a mouthguard. Method: Participants included 23 untrained adults, 11 gymnasts, and 10 weightlifters. Custom mouthguards were fabricated and adjusted so that all teeth were in even contact with light clenching. The standing postural control function was evaluated by the displacement of the center of foot pressure (COP) measured using a gravity center fluctuation meter. Measurement conditions were with and without a mouthguard. Statistical analyses were performed on the differences in COP displacement among participant groups and between mouthguard conditions and the difference in the reduction rate of COP displacement when wearing a mouthguard among participant groups. Results: COP significantly decreased in the order of untrained adults to weightlifters to gymnasts, irrespective of the mouthguard condition. The reduction rate in COP displacement after wearing a mouthguard was greatest in gymnasts. Conclusions: The effect of the mouthguard on postural control function was more pronounced in gymnasts than in untrained adults and weightlifters, and this study suggests that equalization of the occlusal state by wearing a mouthguard contributes to improving postural control function.

Objectives: The purpose of this study was to determine the stability of occlusal contacts based on the left–right distribution of the occlusal contact area, divide participants into well-balanced and unbalanced groups, and clarify the effect of light clenching on the balance ability. Methods: Forty-one healthy men completed occlusal contact examinations with pressure-sensitive films, and the participants were allocated to the balanced occlusal contact (BOC) group or the unbalanced occlusal contact (UOC) group. The balance ability was measured using a center of gravity sway meter. The static balance in standing and dynamic balance using the cross test were assessed. Measurements were performed in the mandibular rest position (RP) or with light clenching (LC). Differences in the balance ability between the participant groups due to clenching and correlations between the static and dynamic balance were analyzed. Results: Differences in the balance ability due to clenching were observed only in the BOC group, with the static balance higher with LC, and the dynamic balance higher in the RP condition (p < 0.01). Significant correlations were observed between the static and dynamic balance except for the UOC group with LC (p < 0.01, p < 0.05). Conclusions: The results of this study suggested that occlusion affects the postural control when occlusal contact is stable but does not affect the postural control when occlusal contact is unstable.