Posters - Material Research

2013 Clinical Oral Implants Research  
The angulation of immediately loaded dental implants like in the 'All-on-4' concept has a crucial effect on the initial bone stress and strain.The literature shows that standard dental implants placed at a 30°angulation cause a significant higher force on the peri-implant bone. Aim/Hypothesis: It was the aim of this study to investigate the biomechanical behavior of different implant designs placed in different angulations and to determine the stress and strain distributions in the surrounding
more » ... one using experimental and numerical methods. Material and methods: Two standard implants with different macro-and micro-designs and one newly developed implant design were inserted into a human mandible segment with varying angulations (straight, 15, 30°). Subsequently the experimentally analysed specimens were scanned using a lCT and the geometry of each specimen was reconstructed threedimensionally. The resulting models were imported into the FE package SolidWorks. The implants were loaded in-vitro with occlusal forces of up to 100 N. The non-osseointegrated state of the immediately loaded implants was simulated by performing so-called contact analyses. Results: Measured implant deflections ranged from 5 to 35 lm at a vertical force of 50 N. Calculated displacements were between 11 lm and 67 lm at a vertical force of 100 N. Maximum stresses for all implants investigated were between 3 and 72 MPa at a vertical load of 100 N. Stress spikes are located in the cortical bone in the region between implant neck and cortical bone. The design of the implant body and the macro-and microthread design clearly has an influence on the peri-implant bone stress and strain for highly angulated implants. Conclusions and clinical implications: The biomechanical results for angulated implant placement illuminate that the implant design is a crucial factor for the peri-implant bone stress. This might be one contributing factor causing cortical crestal bone loss in the long-term for highly angulated implants (30°). Background: The implant bed preparation has a massive impact on the primary implant stability. Depending on the bone quality the primary stability can be very different if the clinician has to use the same set of implant drills. Aim/Hypothesis: It was the aim of this in-vitro study to develop a drill sequence for one implant system, that creates the same primary stability independent of the bone quality. Material and methods: three different drill sequences are utilized to achieve 35 Ncm primary stability for the same implant depending on the different bone qualities D1-D4. Special foam blocks are used which simulate these different bone qualities. The clinician always starts with the drill sequence for soft bone, which is creating an under contoured implant bed preparation. Especially the apical part of the conical implant is used to create stability with the self-cutting thread design. The dimension of the following drills for higher bone qualities are closer to the final implant diameter itself. The aim is to achieve between 35-45 Ncm in every bone quality. An implant motor with an integrated torque control unit is used to determine the primary stability. Results: The primary stability measurements ranged from 25 to 55 Ncm for all bone qualities. The mean value was 39 Ncm. Most of the implants could be placed with a primary stability between 35-45 Ncm. The design of the drill and the correct sequencing clearly influenced the primary stability. Conclusions and clinical implications: The results indicate that it is possible to achieve a standardized predictable primary stability for one implant design in different bone qualities with a corresponding drill set.
doi:10.1111/clr.12250 fatcat:gy2mxdzrdra75jzk3diswlykf4