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.

OBJECTIVES: 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. MATERIALS AND METHODS: 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 4 weeks and 6 months 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 4 weeks and 6 and 13 months after implant placement by means of ISQ values. In addition, periapical radiographs and peri-implant parameters were taken throughout the trial. RESULTS: 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 4 weeks and then increased with statistical significance during 4 weeks to 13 months 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 0.45 mm after 4 weeks and 0.98 and 0.61 mm after 13 months. All of the soft tissue parameters were within normal limits. CONCLUSIONS: The results of this study indicate that the concept of early loading at 4 weeks 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 30 Ncm and 65, respectively.

The influence of thread geometry on implant osseointegration under immediate loading: a literature review.

Implant success is achieved by the synergistic combination of numerous biomechanical factors. This report examines the mechanical aspect of implants. In particular, it is focused on macrodesign such as thread shape, pitch, width and depth, and crestal module of implants. This study reviews the literature regarding the effect of implant thread geometry on primary stability and osseointegration under immediate loading. The search strategy included both in vitro and in vivo studies published in the MEDLINE database from January 2000 to June 2014. Various geometrical parameters are analyzed to evaluate their significance for optimal stress distribution, implant surface area, and bone remodeling responses during the process of osseointegration.

The effect of clinical performance on the survival estimates of direct restorations.

OBJECTIVES: In most retrospective studies, the clinical performance of restorations had not been considered in survival analysis. This study investigated the effect of including the clinically unacceptable cases according to modified United States Public Health Service (USPHS) criteria into the failed data on the survival analysis of direct restorations as to the longevity and prognostic variables. MATERIALS AND METHODS: Nine hundred and sixty-seven direct restorations were evaluated. The data of 204 retreated restorations were collected from the records, and clinical performance of 763 restorations in function was evaluated according to modified USPHS criteria by two observers. The longevity and prognostic variables of the restorations were compared with a factor of involving clinically unacceptable cases into the failures using Kaplan-Meier survival analysis and Cox proportional hazard model. RESULTS: The median survival times of amalgam, composite resin and glass ionomer were 11.8, 11.0 and 6.8 years, respectively. Glass ionomer showed significantly lower longevity than composite resin and amalgam. When clinically unacceptable restorations were included into the failure, the median survival times of them decreased to 8.9, 9.7 and 6.4 years, respectively. CONCLUSIONS: After considering the clinical performance, composite resin was the only material that showed a difference in the longevity (p < 0.05) and the significantly higher relative risk of student group than professor group disappeared in operator groups. Even in the design of retrospective study, clinical evaluation needs to be included.