It is thought that for some sports so called the “agility” accomplishes the key role from the viewpoint of the improvement of the performance and the injury prevention. Therefore we examined the influence of bite up with the oral appliances on the agility.Tested sporting event were cervical retroflexed force. EVA mouthguard and resin splint were used for the oral appliances. Reaction time was measured as a response to stimulated light by the activating time of the masseter muscle and activating time of the main muscle.It is found the reaction time of neck muscles movement tends to be shortened by wearing of the oral appliances.These results were seemed to be based on decrease of a free way space by the bite up with the oral appliances resulted in shortening the reaction time of the masseter and the stabilized occlusion.(141 words)

Background: The “work style reform of physicians” is due to come into effect in April 2024. Cardiovascular surgery involves many life-saving surgeries after hours, and it is expected to be difficult to achieve the upper limit (level A) of 960 h per year and less than 100 h per month for overtime work. In 2021, there were five full-time cardiovascular surgeons, four of whom were responsible for performing emergency surgery for acute aortic dissection in our facility. The ability to provide emergency surgical care with any two-person combination increases the flexibility of staffing for routine surgery or after-hours on-call. The working environment and surgical outcomes of acute aortic dissection under this system are reported, and changes in work style in cardiovascular surgery are discussed. Methods: The surgical outcomes of 39 cases of acute aortic dissection requiring emergency open heart surgery at this hospital during the one-year period from January to December 2021 were investigated. The number of cases (and first assistants) performed by five full-time surgeons were 7(13), 9(6), 12(3), 11(7) and 0(10), respectively. In addition, there were 8 cases of acute aortic dissection requiring urgent stent graft treatment during the same period. The emergency response rate for emergency patients (including those other than acute aortic dissection) was 100% during the same period. Results: The age was 69 years (median), 48.7% were female, 92.3% were Stanford type A, of which 22.2% were DeBakey type II. Shock vital 20.5%, malperfusion 30.8%. The surgical procedures included TAR in 19 cases, PAR in 8 cases, HAR in 12 cases (including 2 Bentall). Concomitant operations were AVR in 5 cases, CABG in 2 cases, TEVAR in 1 case, lower limb arterioplasty in 2 cases and right hemispherectomy in 1 case. Operating time 400 min (median), extracorporeal circulation time 194 min (median), cardiac arrest 108 min (median), selective cerebral perfusion time 125 min (median), lower body circulation arrest 46 min (median). Hospital mortality 7.7%, stroke 12.8%, delayed paraparesis 2.6%. Ventilation time was 1 day (median), hospital stay 23 days (median), 64.1% were discharged at home. Working Environments: 12-13 on-calls per month. Maximum yearly overtime work is 480.5 h with full overtime pay. Exemptions from working after night shift were also possible. Conclusions: The surgical outcomes of acute aortic dissection at our hospital were acceptable. Not having a fixed surgeon enabled a flexible emergency response, and increased the flexibility of staffing for routine surgery and on-call, and was considered to enable both a change in working style and surgical safety while meeting the needs of the community.