Survival and success of tooth-implant-supported and solely implant-supported double-crown-retained overdentures: A prospective study over a period of up to 11 years.

OBJECTIVES: To investigate the long-term performance, over a period of up to 11 years, of tooth-implant-supported and solely implant-supported double-crown-retained overdentures (DCRDs) for complete restoration of the jaw. MATERIALS AND METHODS: Between 2002 and 2015, patients were consecutively enrolled in the study at Heidelberg University Hospital's Department of Prosthodontics. Scheduled and unscheduled visits were both documented on standardized forms. Kaplan-Meier curves were used to evaluate survival and success of the DCRDs. Mixed effects Cox regression was used to identify the potential effects of age, sex, jaw, location of implants, and the number of abutment teeth on the success of the DCRDs. RESULTS: One hundred and thirty-nine DCRDs were placed in 126 participants (mean age: 65.6 ± 9.1 years; 76 [60.3%] men). The mean follow-up period was 4.2 years. Fifty-three (38%) DCRDs were solely implant-supported (213 implants) and 86 (62%) were tooth-implant-supported (239 teeth and 199 implants). Cumulative five-year survival was 96.2% in the implant-supported group and 97.7% in the tooth-implant-supported group. Simultaneous consideration of failures and severe complications revealed cumulative five-year success of 88.2% for implant-supported DCRDs and 81.9% for tooth-implant-supported DCRDs, with no significant difference between the two types of restoration. Cox regression analysis revealed a greater risk of major complications (hazard ratio: 4.87, p = .04) for maxillary DCRDs than for mandibular DCRDs. CONCLUSIONS: Although the study design has limitations, the results show that tooth-implant-supported and solely implant-supported DCRDs are both recommendable treatment options. After a mean follow-up of 4.2 years, survival and success were high. However, minor complications were common and required much aftercare. CLINICAL TRIAL REGISTRATION: This study started in 2005 and was approved by the local review board of the University of Heidelberg. In 2005, clinical trial registration was not yet common. For this reason, the study was not registered.

The up-to-11-year survival and success of implants and abutment teeth under solely implant-supported and combined tooth-implant-supported double crown-retained removable dentures.

OBJECTIVE: This retrospective analysis was designed to compare the survival and success of dental implants in solely implant-supported, double crown-retained removable dentures (DCRDs) and combined tooth-implant-supported DCRDs, due to a lack of data on the latter. MATERIAL AND METHODS: From 2002, patients were consecutively admitted for treatment at the Department of Prosthodontics, University of Heidelberg. Surgical and prosthodontic treatment and scheduled and unscheduled visits were recorded on standardized documentation forms. Kaplan-Meier analysis was used to estimate success (survival without major complications). Cox regression was applied to assess risk factors. RESULTS: From this clinical study, 139 DCRDs on 412 implants and 239 teeth met the inclusion criteria. Fifty-three dentures were implant-supported (213 implants). Eighty-six were supported by teeth and implants. The DCRDs were placed in 126 patients. After an observation period of up to 11.2 years (median: 4.2 years), total implant survival was 99.5% for tooth-implant-supported DCRDs and 93.4% for implant-supported ones. The estimated cumulative success was 97.2% (standard error/SE ± 1.2%) and 85.9% (SE ± 2.4%) at five years, respectively. Complications included implant or tooth loss, peri-implantitis, apical periodontitis and tooth fracture. In terms of abutments, results from multiple Cox regression revealed lower failure rates in tooth-implant-supported dentures (p = .04). No other risk factors were identified. CONCLUSIONS: Within the limitations of this study, survival and success are high for both treatment options. Combining teeth and implants in one DCRD might have a positive effect on the prognosis of the implant and the survival of remaining teeth.