Early loading of the implants showed a good safety profile, with a similar incidence in AEs between the early and conventional loading groups. The benefits to the patient for the early loading procedure were demonstrated by the patient satisfaction question “What does the patient think about the time taken until occlusal loading was started after implantation surgery?” All patients in the early loading group were “satisfied” (76.3 %) or “highly satisfied” (23.7 %), compared with 78.4 % of patients in the conventional loading group who were “satisfied” (56.8 %) or “highly satisfied” (21.6 %). Scores for the other categories of patient satisfaction were similar between the groups, corresponding to similar levels of patient satisfaction with early and conventional loading in other studies with single-tooth implant rehabilitation [63, 64].

The authors recognize that the study has certain limitations. For example, 6 months is a relatively short time for evaluation of a primary efficacy endpoint; generally, a minimum of 1 year is required for scientific validity in implant dentistry. Although the same evaluation as the primary efficacy endpoint (i.e., change in crestal bone level from baseline) was measured at 12 months, in retrospect, the change at 12 months should perhaps have been taken as a more clinically relevant primary efficacy endpoint. Increasingly, clinicians are calling for long-term evidence on dental implants and, as the time that implants have remained in situ in patients has increased over the years, more and more studies of 10, 15, and 20 years and over are being published and show high survival rates and low crestal bone loss [6, 65–71].

Since the softer bone in the maxilla may lead to a greater incidence of late implant failure [72], and therefore may require a longer loading protocol than the early loading protocol in this study [73], in retrospect, it may have been valid to evaluate the outcomes in the posterior maxilla and mandible separately. Similarly, because of the differences in ridge dimensions from premolar to molar sites in both jaws [74], a separate analysis of the crestal bone changes in these areas may have been applicable.