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Background: Due to their increased precision, CAD/CAM generated bars (Computer-Aided Design/ Computer-Aided Manufacturing) are increasingly utilized in implant prosthodontics. For optimal clinical results, surface morphology should promote the integration of soft tissue while minimizing plaque and bacterial retention.
Objective: Despite their clinical use, only limited information on the biological and clinical surface quality of CAD/CAM milled bars is available. The aim of the study was therefore to characterize the surface topography of bars of different manufacturers based on the profilometric analysis and the need for manual post-processing in the laboratory.
Methods: A custom mandibular edentulous cast with four anterior implants was used as a reference cast and reproduced eight times. On each reproduction cast, corresponding scan flags were positioned and digitized. Acrylic 3D printed bar frameworks were produced and sent to the respective production center along with the digital files of the CAD bars for milling. In the course of profilometric analysis, all bars were examined in three critical Regions of Interest (ROI): Transmucosal, labial, basal. Sa and Ra values of each construction were determined. To evaluate the necessary refinishing time eight dental technicians macroscopically evaluated the bars by performing a subjective visual inspection. Kruskal-Wallis H-tests and Tukey and Kramer's post hoc tests were applied to detect differences between the samples.
Results: After profilometric examination, three specimens (Dentsply Sirona: ZDC; Straumann: ZST; CAMLOG: ZCC) demonstrated surface roughness values in the biological acceptable range (Sa 0.2-0.4 μm) in the transmucosal region and provided optimal conditions for a reliable soft tissue adaptation. The Ra measurements revealed values beyond the acceptable threshold in the transmucosal region for three bars (Straumann: ZST; Dentsply Sirona: ZDC; Amann Girrbach: LAC). Four bars (LAC: Amann Girrbach; ZBC: BEGO; Datron: LDC & LDT; Zirkonzahn: ZZC) needed undesirable extensive manual rework. The evaluation of quality and time for manual post-processing by dental technicians confirmed the measurement-based ranking of the bars.
Conclusion: It is desirable to define a clear roughness threshold for the clinical acceptance of transmucosal CAD/CAM generated surfaces. Clinical studies with profilometric data could help to further improve the surface quality of CAD/CAM milled bars and reduce the need for manual reworking time and effort.
Purpose: Scientific evidence is limited regarding the long-term (>10 years) outcomes of large enough numbers of implants (>500) to allow for reliable comparison of subgroups. The purpose of this study was to analyze the outcomes of dental implants placed in an active University Clinic setting and followed for up to 20 years.
Materials and Methods: Data documenting the implant placement, prosthetic reconstruction, and annual follow-up of patients treated at Frankfurt University were extracted from a Structured Query Language database and patients’ written records and evaluated statistically.
Results: Between April of 1991 and May of 2011, 12,737 ANKYLOS® (DENTSPLY Implants Manufacturing GmbH, Mannheim, Germany) implants were placed in 4,206 patients for a variety of clinical indications. The Kaplan–Meier cumulative survival rate (CSR) was 93.3% after 204 months. Most of the failures (198/1.6%) occurred during the first year after implant placement and before prosthesis delivery. A significantly higher (p < .001) number of implants placed in the mandible and in hard quality bone failed than those placed in the maxilla or in weak and normal quality bone. Female patients had significantly higher CSRs (93.7% 204 months) than male patients (92.8% 204 months/p = .029). The implants showed low rates of peri-implant bone loss after 204 months (horizontal: 21 mm: 85.7%, vertical: 21 mm: 85.2%).
Conclusion: ANKYLOS dental implants followed for up to 20 years have high CSRs and low rates of peri-implant bone loss.