On the other hand, there was no correlation between SBP and neuroticism character. For this reason, it is thought that the range of SBP is usually wide compared to DBP. However, there are some reports about the correlation between SBP and patients’ personality trait [20]. Besides, the excessive rise in SBP during the operation may adversely affect the condition of the patients. Therefore, a further study about this relationship is necessary.

Measurement of a stress marker such as cortisol or amylase in saliva is one of the useful methods of stress evaluation. Umeanula reported that patients who received tooth extraction had increased cortisol concentration in saliva and concluded that evaluation of a stress marker is a simple, effective method for stress evaluation [21]. However, measuring the stress marker in saliva costs time and is expense. Alternatively, we used NEO-FFI for the evaluation of patients’ personality trait. NEO-FFI is a simple and easy questionnaire consisting of 50 questions, and we can easily analyze the character tendency of the patients into five dimensions (neuroticism, extraversion, openness, agreeableness, and conscientiousness). Yoshimura et al. revealed the validity of NEO-FFI using a large community sample in Japan [22]. Schwartz-Arad et al. reported that there was a positive correlation between the degree of anxiety and patient’s expectation to experience pain during the implant surgery and concluded that in a stressful pre-surgical situation, the ability to process relevant information may be severely impaired and should not be given to patients just before the surgery [4]. Therefore, this non-invasive and simple method for evaluation of a patient’s character is very useful. Besides, it is thought that the results of NEO-FFI, especially neuroticism and extraversion tendency, serve as a stress reference in not only implant treatment but also general dental treatment.