Two-year Evaluation of a Variable-Thread Tapered Implant in Extraction Sites with Immediate Temporization: A Multicenter Clinical Trial
Bradley S. McAllister, DDS, PhD/James E. Cherry, DMD/Martin L. Kolinski, DDS/Kenneth D. Parrish, DDS, PhD/David W. Pumphrey, DDS/Robert L. Schroering, DMD
Purpose: The purpose of this clinical trial was to evaluate the survival rate, bone remodeling, and soft tissue health surrounding variable-thread tapered implants placed in fresh extraction sites and loaded immediately. Materials and Methods: Sixty implants were placed in 55 patients at six centers according to a predetermined protocol. All implants were placed in extraction sockets and were subjected to immediate temporization. Definitive prostheses were placed within the first year. Clinical and radiographic examinations were performed at implant placement and after 3, 6, 12, and 24 months. Assessments of implant stability, Papilla Index, plaque, peri-implant mucosa, and marginal bone levels were performed at the respective visits. Results: Fifty-five patients were treated and were restored with 58 single crowns and 1 two-unit fixed partial prosthesis. The cumulative survival rate was 98.3% after 2 years. One implant failed prior to 3 months. The mean marginal bone remodeling from implant insertion to 1 year was –0.22 ± 1.30 mm (n = 41), followed by an average bone gain of 0.12 ± 0.77 mm (n = 33) between 12 and 24 months. Mean marginal bone remodeling was –0.10 ± 1.38 mm (n = 35) from implant insertion to 2 years. Papilla size increased significantly over the 2-year study period. Patient assessments of function, esthetics, and self-esteem also showed significant improvement. Conclusion: The 24-month results indicate that the variable-thread tapered implant can be used safely and effectively under demanding conditions as an immediate postextraction tooth replacement. INT J ORAL MAXILLOFAC IMPLANTS 2012;27:611–618.
Key words: dental implant, extraction socket, immediate loading, variable threading