Peri-Implant Tissue Health and Prosthodontic Outcomes of a Cylindrical-Conical Implant with a Progressive Thread Design at Five-Year Follow-Up: A Single-Center Cross-Sectional Retrospective Study

Objectives: We aim to assess the 5-year clinical outcomes of a cylindrical-conical implant system with a progressive thread design and a sandblasted, acid-etched surface and its fixed prostheses under routine clinical conditions. Methods: This retrospective single-center cross-sectional follow-up study included patients treated with implants with a progressive thread design and an internal butt-joint connection between January 2019 and August 2020 at a specialist referral practice in Germany. Of 112 patients treated, 44 (94 implants with fixed restorations) attended the five-year recall. Outcomes were the Functional Implant Prosthodontic Score (FIPS), peri-implant tissue health parameters (bleeding on probing, suppuration, dehiscence, width of keratinized mucosa, and other signs of inflammation), marginal bone level on periapical radiographs, and implant survival. Results: All 94 implants available for examination remained in situ at five years, corresponding to 100% survival among recalled implants. Mean FIPS was 7.6 out of 10 (interproximal 1.3, occlusion 1.8, design 1.6, mucosa 1.4, bone 1.5). Bleeding on probing was absent in 37.2% of implants and present at ≥3 of 6 sites in 30.9%; suppuration was absent in all cases. Bleeding was descriptively more frequent where keratinized mucosa was narrow: implants with <2 mm bled at nearly three times as many sites as those with ≥2 mm. No implant showed a marginal bone level ≥2.0 mm apical to the shoulder. Conclusions: Within the limitations of this retrospective cross-sectional follow-up study, the implant system with a progressive thread design demonstrated favorable 5-year prosthodontic, biological and radiological findings under referral-practice conditions.