Implant-supported maxillary overdentures.

Krennmair G, Krainhöfner M, Piehslinger E. Int J Oral Maxillofac Implants. 2008 Mar-Apr;23(2):343-52. Nelson K, Semper W, Hildebrand D, Özyuvaci H. Int J Oral Maxillofac Implants. 2008 Jul-Aug;23(4):726-32. Implant-supported maxillary overdentures retained with milled bars: maxillary anterior versus maxillary posterior concept - a retrospective study A retrospective analysis of sandblasted, acid-etched implants with reduced healing times with an observation period of up to 5 years PURPOSE: The aim of the present retrospective investigation was to evaluate implant-supported maxillary overdentures using either anterior (group 1) or posterior (group 2) maxilla- ry implant placement. MATERIALS AND METHODS: Maxillary overdentures were planned with support by either 4 implants placed in the maxillary anterior region (group 1) or 6 to 8 im- plants placed in augmented maxillary posterior regions (group 2, bilateral sinus augmentation) and anchored either on an anterior or on 2 bilaterally placed milled bars. Cumulative implant survival rate, peri-implant conditions (marginal bone loss, pocket depth, Plaque Index, Gingi- val Index, Bleeding Index, and Calculus Index) and the incidence and type of prosthodontic maintenance were assessed and compared for the 2 groups. In addition, the cumulative survival rate for implants placed in grafted regions was compared with that of implants placed in nongrafted regions. RESULTS: Thirty-four patients (16 for group 1 and 18 for group 2) with 179 implants were available for follow-up examination after a mean period of 42.1 ± 20.1 months. Four initially placed implants failed to osseointegrate and were replaced, but no further losses were seen during the loading period, for a 5-year cumulative implant survival rate of 97.8%. No differences in implant survival rates were seen between either the group-1 (98.4%) and group-2 (97.4%) concepts or nongrafted (98.0%) and grafted (97.5%) implants. The peri-implant parameters showed a healthy soft tissue, good oral hygiene, and an acceptable degree of peri-implant marginal bone loss. The rigid fixation of all overdentures was associated with a low incidence of pros- thodontic maintenance, without any significant differences between the 2 groups. CONCLUSION: In well-planned overdenture treatment programs, a high survival rate and excellent peri-implant conditions can be achieved for implants placed in the ante- rior or posterior maxilla. Rigid anchorage of maxillary over- dentures either on an extended anterior milled bar or on 2 bilateral posterior milled bars provides for a low incidence of prosthodontic maintenance. (Comparative Cohort Study) INT J ORAL MAXILLOFAC IMPLANTS 2008; 23:343–352. PURPOSE: The aim of this study was to evaluate the suc- cess rate of 2 different implant systems with sandblasted and acid-etched modified surfaces loaded after reduced healing periods. MATERIALS AND METHODS: One-hundred seventeen patients with a mean observation period of 3.75 years (24 to 61 months) were included in this evaluation. Chart reviews of a standardized recall program were evaluated. All 532 placed implants showed an unloaded healing time of 6 weeks in the mandible and 12 weeks in the maxilla. At ab- utment placement a torque value of 35 Ncm was one of the primary variables, and the success of the implants over time was determined by the criteria of Buser et al. The survival was analyzed using Kaplan-Meier method, and the proba- bility of an event within 1 group independent of time was evaluated using the chi-square test and Fisher exact test. RESULTS: Of the 532 implants, 235 were placed in female and 297 in male patients; 448 implants were located in the maxilla and 84 in the mandible. Three implants were lost prior to abutment connection in 3 patients. Life table analy- ses show an overall success rate of 99.4% at 5 years, as no implants were lost after abutment connection. There was no significant association of the implant type (P = .185), gender (P = .99), or jaw (maxilla/mandible; P = .06) and the survival of the implants within this study. CONCLUSION: Based on the data found in this investiga- tion, it can be concluded that implants with sandblasted, acid-etched surfaces can be restored after a 6- to 12-week healing period with a high predictability of success. INT J ORAL MAXILLOFAC IMPLANTS 2008;23:726–732 Long-Term Study Long-Term Study