Stress distribution and its magnitude during loading heavily influence the osseointegration of dental implants. Currently, no high-resolution, three-dimensional method of directly measuring these biomechanical processes in the peri-implant bone is available. The aim of this study was to measure the influence of different implant materials on stress distribution in the peri-implant bone. Using the three-dimensional ARAMIS camera system, surface strain in the peri-implant bone area was compared under simulated masticatory forces of 300 N in axial and non-axial directions for titanium implants and zirconia implants. The investigated titanium implants led to a more homogeneous stress distribution than the investigated zirconia implants. Non-axial forces led to greater surface strain on the peri-implant bone than axial forces. Thus, the implant material, implant system, and direction of force could have a significant influence on biomechanical processes and osseointegration within the peri-implant bone.

The implementation of CAD software in the digital production of implant prosthetics stands as a pivotal aspect of clinical dentistry, necessitating high precision in the alignment of implant scanbodies. This study investigates the influence of scanbody geometry and the method of superimposing in CAD software when determining 3D implant position. A standardized titanium model with three bone-level implants was digitized to create reference STL files, and 10 intraoral scans were performed on Medentika and NT-Trading scanbodies. To determine implant position, the generated STL files were imported into the Exocad CAD software and superimposed—automatically and manually—with the scanbody geometries stored within the software’s shape library. Position accuracy was determined by a comparison of the 3D-defined scanbody points from the STL matching files with those from the reference STL files. The R statistical software was used for the evaluation of the data. In addition, mixed linear models and a significance level of 0.05 were applied to calculate the p-values. The manual overlay method was significantly more accurate than the automatic overlays for both scanbody types. The Medentika scanbodies showed slightly superior precision compared to the NT-Trading scanbodies. Both scanbody geometry and the type of alignment in the CAD software significantly affect digital workflow accuracy. Manual verification and adjustment of the automatic alignment process are essential for precise implant positioning.

Purpose: The aim of this study was to investigate the superimposition of CBCT data with virtual models of the oral situation directly generated using an IOS and with indirectly generated plaster models. Methods: Two different radiopaque jaw models were first scanned using a CBCT unit. Secondly, ten scans using an IOS and ten alginate impressions were made. The alginate impressions were cast with plaster and the plaster models were digitized using a laboratory scanner. Virtual Reference models generated with an industrial scanner were superimposed with the data sets of the virtual models using both a best-fit procedure on the palate and on the teeth. Deviations in two toothless areas were statistically evaluated. Results: The superimposition of the directly generated models with the CBCT-based datasets showed lower deviations. Lower deviations were also calculated for the best-fit based on the teeth. The lowest deviations were found for model 1 with direct modeling and superimposition over the teeth with 0.008 mm (indirect: 0.210 mm; P = 0.001) and for model 2 with 0.010 mm (indirect 0.106 mm; P = 0.002). Conclusions: Virtual models of the oral situation generated directly using an IOS are better suited for superimposing with CBCT-based datasets than indirectly generated ones. The best-fit on the teeth is superior to that on the palate. Graphical

Purpose: To date, the qualitative and quantitative recording of biomechanical processes in dental implants represents one of the greatest challenges in modern dentistry. Modern, dynamic, 3D optical measurement techniques allow highly constant and highly accurate measurement of biomechanical processes and can be superior to conventional methods. This work serves to establish a new measurement method. Materials and Methods: A comparative analysis was undertaken for two different measurement systems, two conventional strain gauges versus the 3D optical two-camera measurement system ARAMIS (GOM GmbH, Braunschweig, Germany), as they detected surface changes on an artificial bone block under masticatory force application. Two implants (Straumann Standard Implants Regular Neck, Straumann GmbH, Freiburg, Germany) were placed in the bone block, and three different three-unit bridges were fabricated. Increasing masticatory forces, from 0 to 200 N, were applied to the bone block via each of these bridges and the inserted implants. Fifteen repetitions of the test were performed using a universal testing machine. The computer unit of the ARAMIS system was used to simultaneously integrate the surface changes recorded by the strain gauges and the ARAMIS system. The areas on the bone block examined by the dynamic 3D optical measurement method corresponded exactly to the locations and extent of the strain gauges. A statistical comparative analysis was carried out separately for the strain gauges and the corresponding optical measuring surface at the defined force magnitudes. The equivalence test and the intraclass correlation served as statistical means. Results: In the case of the intraclass correlation, a clear concordance of both measurement methods could be shown for all examined cases. For the equivalence test, no significance could be shown in individual cases. Conclusion: The accuracy of the modern, dynamic, 3D optical measurement method is comparable to that of conventional strain gauges. On this basis, versatile new research approaches in the field of biomechanics of dental implants can be pursued by establishing this method.

Constantin Motel, Manfred Wichmann, Ragai Edward Matta Department of Prosthodontics University hospital Erlangen, Glueckstr. 11, 91054 Erlangen, Germany -Abstract to the congress of the European Association for Osseointegration , October 5-7th 2017, Madrid- “Impact of different scan bodies and scan strategies on the accuracy of digital implant impression” Background and aims: The