A 10-year retrospective, clinical follow-up study evaluating Neoss implant system placed in conjunction with or without GBR procedures

Background

Implant-supported tooth replacement is a commonly used method to replace missing teeth. With a growing population with increased life expectancy including increased implant placement in younger patients, long-term validation of implant treatment is of great importance.

Aim/Hypothesis

The aim of this study was to retrospectively analyze the long-term clinical performance of Neoss implants when placed in conjunction with or without adjunctive guided bone regeneration (GBR) procedures.

Material and Methods

The study group consisted of the first 50 consecutive patients treated with Neoss dental implants (Bimodal surface) at a single clinic and followed for 10 years (9.3–11.2 years). The patients were in need of implant treatment due to single (n = 20), partial (n = 21) or total (n = 9) loss of their teeth. Overall, 183 implants were placed, 126 in extraction sockets in conjunction with GBR procedure (Bio-Oss combined with a resorbable Bio-Guide membrane) and 57 in healed bone without GBR. Healing abutments were connected after a healing period of 3–6 months for 89 implants. For 37 implants a healing abutment was connected at implant surgery and for 57 implants a crown bridge was fitted within a few days implementing immediate early function. The number of failures, withdrawn and drop-out implants was recorded in a lifetable analysis. All available intraoral radiographs from baseline and 1-, 3-, 5-, and 10-year follow-up visits were analyzed with respect to periimplant bone level remodeling.

Results

32 patients with 123 implants attended the 10-year re-call visit. A total of 9 implant failures were recorded, 8 during the first year in function and 1 after 4 years giving a total cumulative survival rate (CSR) of 95.0%. 8 implant failures occurred in the GBR group (CSR- 93.5%) and only 1 in the non-GBR group (CSR- 98.2%). Based on all available radiographs, the bone level was situated 1.3 ± 0.8 mm (n = 159) below the implant-abutment junction at baseline (permanent prosthetic delivery), and 1.7 ± 0.8 mm (n = 104) after 1-year, 1.7 ± 1.1 mm (n = 151) after 3 years, 1.5 ± 0.9 mm (n = 132) after 5 years and 1.6 ± 0.9 mm (n = 119) after 10 years of follow-up. Based on paired baseline and 1-, 3-, 5- and 10-year radiographs, mean bone loss was 0.2 ± 0.9 mm (n = 98), 0.6 ± 1.3 mm (n = 135), 0.3 ± 1.1 mm (n = 120) and 0.4 ± 1.2 (n = 111) respectively. No statistically significant differences were seen between implants placed in conjunction with or without GBR with respect to implant survival or bone loss.

Conclusion and Clinical Implications

The Neoss implant system showed good clinical and radiographic outcome after up to 10 years in function. Implants placed in association with bone regenerative procedures showed similar peri-implant bone remodeling as when placed in healed bone situations. A trend with lower implant survival rates were noticed for implants placed with GBR, although this could not be shown statistically.