Prospective clinical study to evaluate the success and survival of two-piece zirconia implants : a single-center study. 12-month results

Purpose: To evaluate the survival and success rates of a novel two-piece zirconia implant system restored with screw-retained glass–ceramic crowns over 12 months, including assessment of bone levels, soft tissue parameters, and patient-reported outcome measures. Methods: Twenty-four patients received single two-piece zirconia implants (CERALOG® Hexalobe) in healed sites. After a 6-month healing period, implants received provisional screw-retained crowns on PEKK temporary abutments, followed by definitive lithium disilicate crowns (IPS e.max Press) on PEKK abutments. Clinical and radiographic examinations were performed at implant placement, re-entry, definitive loading, and 12-month follow-up, along with patient-reported outcome measures. Results: The implant survival rate at 12 months was 60.9%. Nine implants were lost: two due to lack of osseointegration at re-entry, four due to mobility after loading, and three due to fractures in the coronal third after loading. Surviving implants showed stable soft tissue parameters with mean probing pocket depths of 2.7 ± 0.7 mm at 12 months. The mean distance from implant shoulder to first bone contact decreased from 1.9 ± 0.6 mm at loading to 1.4 ± 0.6 mm at 12 months. Patients with surviving implants reported high satisfaction scores (4.8 ± 0.4) for function and aesthetics. Conclusions: The two-piece zirconia implant system with screw-retained restorations showed unsatisfactory survival rates. The combination of ceramic implants with screw-retained prosthetic restorations may have contributed to the higher failure rates observed. As a pilot study with a relatively small sample size, these findings should be confirmed by larger multicenter studies to validate these preliminary results.