Fifteen patients were recruited for the present study. All the patients had never received implant treatment in the past. The patients were not accepted into this study if they met any of the following exclusion criteria: (1) experience of implant treatment in the past, (2) general contraindications to implant surgery, (3) moderate or severe hypertension or cardiovascular system disease, and (4) mental disease. All the patients were informed about the purpose of this study and provided their signed informed consent.

To evaluate the patients’ personality trait, NEO-Five Factor Inventory (NEO-FFI) was used. All the patients answered 50 questions at the first visit and scored 0–40 in five dimensions: neuroticism, extraversion, openness, agreeableness, and conscientiousness. The index of physical stress was evaluated by blood pressure and pulse rate. All the patients’ blood pressure (systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP)) and pulse rate (PR) were measured by a biological information monitor (Moneo BP-A308, OMRON COLIN Co., Tokyo, Japan) at the first visit, entering into the operation room without local anesthesia given before and after the surgery. Elevation rates (ER) of each blood pressure and PR were calculated. Rate pressure product (RPP) was also calculated by SBP and PR.

All the patients received implant surgery under local anesthesia (2 % lignocaine with 1:80,000 epinephrine; DENTSPLY International Inc., PA, USA), and a one- or two-stage surgical approach was selected according to the initial torque values and resonance frequency analysis (RFA). Screw-type dental implants (GENESiO Plus, GC Company, Tokyo, Japan) were used in all the patients.

SBP_ER, DBP_ER, MBP_ER, PR_ER, and RPP_ER and five dimensions of NEO-FFI were used as correlated variables. For statistical analysis, Spearman’s rank correlation was used and p < 0.05 was considered statistically significant.

This study was approved by the Ethics Committee of Osaka University Graduate School of Dentistry (H24-E16-1).