Randomized controlled clinical trial comparing one‐piece and two‐piece dental implants supporting fixed and removable dental prostheses: 4‐ to 6‐year observations

• Published in: Clinical oral implants research 2017-12, Vol.28 (12), p.1553-1559
• Main Authors: Gamper, Felix B., Benic, Goran I., Sanz‐Martin, Ignacio, Asgeirsson, Asgeir G., Hämmerle, Christoph H. F., Thoma, Daniel S.
• Format: Article
• Language: English
• Subjects: Cementing; Clinical trials; comparison; complications; crown; Dental implants; Dental materials; Dental prosthetics; Dental restorative materials; Dentistry; denture; fixed; Fractures; humans; long term; Loosening; Mucosa; Mucositis; partial; Prostheses; radiographic; removable denture; Skewed distributions; Statistical methods; Surgical implants; Survival; Teeth; Transplants & implants; Veneering
• ISSN: 0905-7161; 1600-0501
• DOI: 10.1111/clr.13025

Objectives To test whether or not a one‐ (S1) and a two‐piece (S2) dental implant systems render the same biological, technical, and esthetic outcomes regarding implants and implant‐supported reconstructions over an observation period of 4 to 6 years. Materials and methods Sixty patients were randomly assigned to receive S1 or S2 implants. The implants were restored with either fixed or removable prostheses. The insertion of the final reconstruction was chosen as baseline. One‐year and 4‐ to 6‐year (FU‐5) measurements included biological (e.g. marginal bone level, probing pocket depth, peri‐implant mucositis, and peri‐implantitis), technical (e.g. fracture or loosening of prosthetic screws, fracture or loosening of abutments, fracture of framework, and/or veneering ceramic (minor, major), loss of retention for cemented restorations), and esthetic parameters (visibility of the crown margin, shimmering of the implant through the mucosa, the level of the facial margo mucosae compared to the contralateral tooth or implant site and the modified papilla index) for implants and reconstructions. Survival and success rates of implants and reconstructions were calculated. Because of the asymmetric data distributions, nonparametric statistical methods were applied. Results The implant‐based analysis revealed a cumulative implant survival rate of 97.9% (S1: 96.6%; S2: 98.9%) at FU‐5. The median marginal bone level for group S1 changed from 0.51 mm at baseline to 0.49 mm at FU‐5 and for group S2 from 1.02 mm to 1.35 mm (P  0.05). Conclusions Both implant systems reveal high survival rates on the implant and prosthetic level. Apart from marginal bone‐level changes, biological and technical outcomes did not reveal significant differences between the two implant systems.