Abstract
Background: Single implants yield predictable survival and success using various treatment protocols. Innovations in design and surface texture improved survival and ensured crestal bone stability, crucial to avoiding biological complications. This study focuses on survival and peri-implant crestal bone remodeling during healing and function of single hybrid-surface implants (Machine Surface Coronal, MSc, Southern Implants Pty Ltd., Irene, South Africa), featuring a minimally rough coronal region and moderately rough body. The specific aims were firstly to compare the clinical outcome between 3 surgical protocols and secondly to assess whether the outcome is affected by macroscopic implant design. Methods: Clinical records of 120 consecutively placed single MSc-implants in private practice were scrutinized after 12-62 months in function. Implants were placed using one of three surgical protocols as selected by the surgeon based on clinical judgment and treatment indication: flap-healed surgery with healing abutment (HA), flapless surgery with HA, or immediate implant placement (IIP) with HA. Six different implant types, albeit with the same MSc-surface feature, were utilized, based on individual clinical indications. Radiographical crestal bone level changes over time were analyzed and effect of implant design, gender, smoking status and surgical protocol was explored. Results: 101 implants was available for analysis. Six implants failed prior to loading (5%); 30% in smokers versus 3.3% in non-smokers. Initial bone remodeling, due to biologic width formation, was 0.762 mm (SD 0.940) at time of loading and 0.933 mm (SD 1.057) after 2 years (p = 0.07). Steady state bone levels at final recall (12-62 months; mean 24) were irrespective of implant type (p = 0.51), surgical protocol (p = 0.10), gender (p = 0.557) or smoking habit (p = 0.27). 54% of the implants showed bone gain between loading and final, whereas only 3% had bone loss above 3 mm. Conclusions: Under daily clinical conditions, MSc-hybrid implants yield predictable clinical outcomes in line with contemporary implant systems, irrespective of implant length and diameter. A 5.9% early failure rate was found irrespective of smoking status, with no late failures. Failure rate dropped to 3.3% when smokers were excluded. Crestal bone remodeling at the time of loading, mimicking biologic width formation, as well as bone level changes over time, is indicative of a healthy peri-implant steady state irrespective of the surgical protocol.