Eighteen patients (11 women, 7 men; mean age 60.2 years) fulfilled the inclusion criteria. There was no significant difference between men (57.3 ± 5.0 years) and women (63.1 ± 6.0 years). After measuring the BTMs and assessing bone density, 35 implants were placed (18 MK-III, 17 SLA). The mean follow-up duration was 21.4 months (Table 1), during which time follow-up observations were made by dental hygienists at 3-month intervals. There was no evidence of peri-implantitis or implant loss over the 6–48 months post-implantation.

The overview on BTM values is shown in Fig. 3. The patients were divided into a normal group that had BTM values within normal limits (n = 9, 2 women, 7 men) and an abnormal group (n = 9, all women) with at least one BTM value outside the normal range. The mean age of the normal group was significantly higher than that of the abnormal group (P = 0.038, r = 0.49). The number of male patients within normal BTM values was significantly more than that of female patients (P = 0.0043, r = 0.66) (Table 2).

The cancellous bone density is shown in Figs. 4 and 5. The cancellous bone density was significantly higher in the normal group than in the abnormal group (P = 0.0012, r = 0.55). In the abnormal group, the cancellous bone density showed no significant difference between the SLA implants and MK-III implants at baseline (P = 0.121, r = 0.41).

The MBLs are shown in Fig. 6. Among the patients who had at least one BTM measurement outside the normal range, all women, the MBL was significantly larger among those with MK-III implants than those with SLA implants in the follow-up period (P = 0.0045, r = 0.76).