Immediately Loaded Fixed Full-Arch Implant-Retained Prosthesis: Clinical Analysis When Using a Moderate Insertion Torque.

PURPOSE: This study uses intentionally tilted implants with a moderate insertion torque to retain an immediately loaded fixed full-arch implant-retained prosthesis using four implants. The aims of this study were to determine the likelihood that this type of implant-retained prosthesis can be predictably provided on the day of implant placement, the survival rate when providing immediate load, and the importance of insertion torque on the survival of the implants. MATERIALS AND METHODS: All implants that were placed after August 1, 2015 and before December 31, 2016 at the ClearChoice Dental Implant Center of Minneapolis were recorded. The performance of these implants was followed to determine the success rate in the category of "intention to treat" where the treatment is provided on the same day as implant placement. Insertion torque was recorded for all implants. Implants were followed to determine survival of the implants and complications observed. RESULTS: Between August 1, 2015 and December 31, 2016, a total of 1,903 implants were placed. These implants were utilized to support 441 prostheses, with 440 actually being restored with a provisional prosthesis on the day of implant placement. Mean follow-up time was 484 days with a maximum of 972 days and a median of 474 days. A total of 36 implants failed to achieve osseointegration, resulting in an overall survival rate of 98.1% with a confidence interval (CI) of 98.7% to 97.5%. Survival was 97.6% in the maxilla and 98.9% in the mandible. Insertion torque of less than 15 Ncm (n = 80, 77 survival), between 15 and 34 Ncm (n = 122, 120 survival), and greater than 35 Ncm (n = 1,701, 1,670 survival) demonstrated no difference in implant survival. CONCLUSION: Based on this study of 1,903 implants placed between August 1, 2015 and December 31, 2016, the following observations were made: (1) this surgical/prosthetic treatment approach succeeded in the "intention to treat" category with 440/441 (99.8%) prostheses inserted on the day of implant surgery; (2) overall implant survival was 98.1%; (3) insertion torque appeared to have no effect on implant survival.

The effect of increased crown-to-implant ratio on single-tooth locking-taper implants.

PURPOSE: It has been proposed that increased crown heights lead to greater crestal stresses on dental implants, crestal bone loss, and other complications. The purpose of this study was to evaluate the effect of increased crown-to-implant ratio (C/IR) on single-tooth implants. MATERIALS AND METHODS: A retrospective cohort study was conducted between July 2001 and August 2003. The cohort was composed of patients who had at least one single-tooth Bicon implant restored with a cementless restoration and attended recall examinations in 2004, 2005, and 2007, during which several clinical and radiographic variables were documented. Descriptive statistics and univariate and multivariate mixed-effects regression models, adjusted for multiple implants in the same patient, were used. RESULTS: The cohort was composed of 81 subjects who received 326 Bicon implants. The mean duration of follow-up was 70.7 months. Mean change in the mesiodistal crestal bone levels was -0.33 mm. The mean C/IR was 1.6 (range, 0.79 to 4.95). Forty implant restorations (16%) had a C/IR ≥ 2. Implant restorations with increased C/IR were significantly more likely to have increased mesiodistal crown width, larger implant diameter, larger distance to mesial and distal adjacent structures, and deeper sulcular probings. Increased C/IR had a statistically significant effect in the loosening of maxillary anterior Integrated Abutment Crowns (Bicon) as well as a significant effect in the fracture of 2-mm-wide titanium abutment posts used to restore posterior areas. A C/IR up to 4.95 did not lead to an increased risk of crestal bone loss or to an increase in implant failures, crown failures, or crown fractures. CONCLUSION: Larger C/IR was associated with a significant increase in prosthetic complications but had no significant effect on crestal bone levels on single-tooth locking-taper implants.