Early loading of splinted implants supporting a two‐unit fixed partial denture in the posterior maxilla: 13‐month results from a randomized controlled clinical trial of two different implant systems

Abstract

The aim of this study was to evaluate early-loaded implants supporting a two-unit fixed dental prosthesis in the posterior maxilla and to compare the clinical and radiological outcomes of two different implant systems in terms of success rates, implant stability quotient (ISQ) values, and peri-implant parameters. Thirty patients with the unilateral loss of two consecutive maxillary posterior teeth were randomly assigned to two different implant systems: SLActive Bone level implant (Institut Straumann AG, Basel, Switzerland) in the control group and CMI IS-II active implant (Neobiotech Co., Seoul, Korea) in the experimental group. The patients received provisional and definitive two-unit fixed prostheses at 4weeks and 6months after implant surgery, respectively. The peak insertion torque was recorded at surgery. The stability of each implant was evaluated during surgery and at 2, 3, and 4weeks and 6 and 13months after implant placement by means of ISQ values. In addition, periapical radiographs and peri-implant parameters were taken throughout the trial. Overall, comparable results were obtained between the control and experimental groups in terms of insertion torque, ISQ values, marginal bone loss, and peri-implant soft tissue parameters. All 60 implants had 100% of success rate. The average insertion torque was 36.83 ± 6.09 (control) and 35.33 ± 3.20 (test) Ncm. The ISQ values remained steady until 4weeks and then increased with statistical significance during 4weeks to 13months after surgery. Both groups exhibited no stability dip during the early phase of healing. The average marginal bone loss from the baseline of implant placement for the control and experimental groups was 0.38 and 0.45mm after 4weeks and 0.98 and 0.61mm after 13months. All of the soft tissue parameters were within normal limits. The results of this study indicate that the concept of early loading at 4weeks after placement in the posterior maxilla can be an effective treatment option, even in the areas of low bone density, when implants satisfy the inclusion criteria of minimum insertion torque and ISQ of 30Ncm and 65, respectively.