Long-term survival of Astra Tech vs Straumann dental implants and restorations.

DESIGN: This randomized controlled trial (RCT) compared the survival and complications rates between two well-established implant systems, namely AST (OsseoSpeed TX 3.0-5.0 S, TX 4.5; Astra Tech Implant System, Dentsply Sirona) and STM (Straumann Bone Level Implants 3.3, 4.1, 4.8 mm, SLA active; Straumann AG), supporting fixed restorations, over a 10-year follow-up period.

CASE SELECTION: Sixty-four healthy patients with good oral hygiene participated in this study at the Clinic of Reconstructive Dentistry, University of Zurich, Switzerland. A total of 98 implants were placed in these patients, who were randomly assigned to either the AST or the STM groups. Subsequently, patients received implant-supported fixed restorations and were followed up for 10 years. The assessments were performed at the implant insertion stage after the final implant restoration was fitted (baseline), and then at 1, 3, 5, 8, and 10 years post-baseline assessment. The outcome measures included implant survival, marginal bone level changes, prosthesis (supra-structure) complications, and clinical periodontal measures.

DATA ANALYSIS: Data analysis was performed with SAS 9.4 software. Data were recorded at both the patient and implant levels. A range of statistical tests such as Wilcoxon-signed-rank, Wilcoxon-Mann-Whitney, F-tests, and Chi-squares were used. Linear models and linear mixed models were applied at the patient and implant levels, respectively.

RESULTS: The study reported survival rates of 89.7% for AST and 96.8% for STM, after 10 years. The AST implants showed a higher incidence of prosthesis complications, such as chipping, screw loosening and fracture, abutment fracture, and implant crown loss. Biological complications, including peri-implant mucositis and peri-implantitis, were more prevalent in the STM group.

CONCLUSIONS: Overall, the study suggests that both implant systems have equally high survival rates and stable marginal bone levels. Therefore, both systems are considered viable options for supporting fixed restorations at restoring missing teeth in the maxilla and mandible.