Immediate and Early Loading of Hydrothermally Treated, Hydroxyapatite-Coated Dental Implants: 2-Year Results from a Prospective Clinical Study

This investigation was undertaken to determine if multithreaded implants partially coated with plasma-sprayed hydroxyapatite (HA) could be effectively loaded earlier than 3-6 months after placement. Forty-eight patients (22 men, 26 women) were enrolled in the study and received 48 implants. The population was divided into 2 groups: A implants (n = 23) were loaded immediately on the day of surgery and group B implants (n = 19) were loaded 3 weeks after surgery. Cone beam computerized tomography (CBCT) scans were taken preoperatively to aid in treatment planning. Bone density was evaluated by tactile feedback during surgery. Insertion torque was recorded at time of implant placement. Resonance frequency analysis, performed on the day of surgery, at the time of loading, and at 6, 12, and 24 months, was used to record implant stability according to the unit's implant stability quotient (Osstell ISQ). Standardized radiographs were taken at time of implant placement and at 6, 12, and 24 months to measure crestal bone stability. Bone level changes were measured by software (Image J). Bone quality was judged as either type 1 (n=1), 2 (n=31), 3 (n=15), or 4 (n=1). There were no failures in the group A (survival = 100%, n=23/23) and 1 failure in group B (survival=94.7%, n = 18/19). After 2 years in function, cumulative mean radiographic bone loss was 0.75 +/- 0.50mm (maxillae: 0.92 +/- 0.49 mm, n=14; mandibles: 0.67 +/- 0.49 mm, n=28). No differences in bone levels were noted between implants placed in previously augmented and nonaugmented sites, and there were no periodontal or soft tissue complications. After 2 years in function, implants partially coated with plasma-sprayed and hydrothermally treated HA were clinically predictable when restored in occlusion immediately after or within 3 weeks of implant placement.