Development of a test bench for biomechanical simulation-a preliminary study of mandibular forces.

Purpose: The aim of this study is to develop a test bench, which integrates different complexity levels and enables in that way a flexible and dynamic testing for mid and long term intervals as well as testing of maximum loads till implant failure of different osteosynthesis systems on the mandible. Material and Methods: For this purpose, an analysis of the state of the art regarding existing test benches was combined with interviews of clinical experts to acquire a list of requirements. Based on these requirements a design for a modular test bench was developed. During the implementation of the test stand, functional tests were continuously carried out and improvements made. Depending on the level of complexity, the test bench can be used either as an incorporated variant or as a standalone solution. In order to verify the performance and the degree of fulfilment of the requirements of these two variants of the test bench, preliminary studies were carried out for all levels of complexity. In these preliminary studies, commercially available osteosynthesis and reconstruction plates were investigated for their biomechanical behaviour and compared with data from the literature. Results: In total, fourteen test runs were performed for the different levels of complexity. Firstly, five test runs were executed to test the simplified load scenario in the incorporated variant of the test bench. High forces could be transmitted without failure of the miniplates. Secondly a quasi-static test scenario was examined using the incorporated variant with simplified load insertion. Five experiments with a number of cycles between 40,896 and 100,000 cycles were carried out. In one case the quasi-static testing resulted in a fracture of the tested reconstruction plate with a failure mode similar to the clinical observations of failure. The last four test runs were carried out using the standalone variant of the test bench simulating complex load patterns via the insertion of forces through imitated muscles. During the test runs joint forces were measured and the amplitude and vector of the resulting joint forces were calculated for both temporomandibular joints. Differences in the force transmission depending on the implant system in comparison to the zero sample could be observed. Conclusion: The presented modular test bench showed to be applicable for examination of the biomechanical behavior of the mandible. It is characterized by the adjustability of the complexity regarding the load patterns and enables the subsequent integration of further sensor technologies. Follow-up studies are necessary to further qualify and optimize the test bench.

Unique Device Identification-Based Linkage of Hierarchically Accessible Data Domains in Prospective Surgical Hospital Data Ecosystems: User-Centered Design Approach.

BACKGROUND: The electronic health record (EHR) targets systematized collection of patient-specific, electronically stored health data. The EHR is an evolving concept driven by ongoing developments and open or unclear legal issues concerning medical technologies, cross-domain data integration, and unclear access roles. Consequently, an interdisciplinary discourse based on representative pilot scenarios is required to connect previously unconnected domains. OBJECTIVE: We address cross-domain data integration including access control using the specific example of a unique device identification (UDI)-expanded hip implant. In fact, the integration of technical focus data into the hospital information system (HIS) is considered based on surgically relevant information. Moreover, the acquisition of social focus data based on mobile health (mHealth) is addressed, covering data integration and networking with therapeutic intervention and acute diagnostics data. METHODS: In addition to the additive manufacturing of a hip implant with the integration of a UDI, we built a database that combines database technology and a wrapper layer known from extract, transform, load systems and brings it into a SQL database, WEB application programming interface (API) layer (back end), interface layer (rest API), and front end. It also provides semantic integration through connection mechanisms between data elements. RESULTS: A hip implant is approached by design, production, and verification while linking operation-relevant specifics like implant-bone fit by merging patient-specific image material (computed tomography, magnetic resonance imaging, or a biomodel) and the digital implant twin for well-founded selection pairing. This decision-facilitating linkage, which improves surgical planning, relates to patient-specific postoperative influencing factors during the healing phase. A unique product identification approach is presented, allowing a postoperative read-out with state-of-the-art hospital technology while enabling future access scenarios for patient and implant data. The latter was considered from the manufacturing perspective using the process manufacturing chain for a (patient-specific) implant to identify quality-relevant data for later access. In addition, sensor concepts were identified to use to monitor the patient-implant interaction during the healing phase using wearables, for example. A data aggregation and integration concept for heterogeneous data sources from the considered focus domains is also presented. Finally, a hierarchical data access concept is shown, protecting sensitive patient data from misuse using existing scenarios. CONCLUSIONS: Personalized medicine requires cross-domain linkage of data, which, in turn, require an appropriate data infrastructure and adequate hierarchical data access solutions in a shared and federated data space. The hip implant is used as an example for the usefulness of cross-domain data linkage since it bundles social, medical, and technical aspects of the implantation. It is necessary to open existing databases using interfaces for secure integration of data from end devices and to assure availability through suitable access models while guaranteeing long-term, independent data persistence. A suitable strategy requires the combination of technical solutions from the areas of identity and trust, federated data storage, cryptographic procedures, and software engineering as well as organizational changes.

A Holistic Approach for the Identification of Success Factors in Secondary Cleft Osteoplasty.

Cleft lip and palate belong to the most frequent craniofacial anomalies. Secondary osteoplasty is usually performed between 7 and 11 years with the closure of the osseus defect by autologous bone. Due to widespread occurrence of the defect in conjunction with its social significance due to possible esthetic impairments, the outcome of treatment is of substantial interest. The success of the treatment is determined by the precise rebuilding of the dental arch using autologous bone from the iliac crest. A detailed analysis of retrospective data disclosed a lack of essential and structured information to identify success factors for fast regeneration and specify the treatment. Moreover, according to the current status, no comparable process monitoring is possible during osteoplasty due to the lack of sensory systems. Therefore, a holistic approach was developed to determine the parameters for a successful treatment via the incorporation of patient data, the treatment sequences and sensor data gained by an attachable sensor module into a developed Dental Tech Space (DTS). This approach enables heterogeneous data sets to be linked inside of DTS, archiving and analysis, and is also for future considerations of respective patient-specific treatment plans.

The Influence of Thrust Force on the Vitality of Bone Chips Harvested for Autologous Augmentation during Dental Implantation.

Bone drill chips that are collected during implant site preparation can be reused as autologous bone-grafting material for alveolar ridge augmentation. This study characterized five market-leading implant drill sets regarding their geometric properties and ability to produce vital bone chips. The drill geometry of each tool of five commercial implant drill sets was characterized while using optical profile projector devices and SEM. Bone chips were collected during the in vitro preparation of porcine jaw bone with the various drill sets. Produced bone chip masses were measured. The bone chips were cultured in vitro and the number of outgrown cells was determined and measurand for vitality. Furthermore, the thrust force and cutting torque were recorded to examine the mechanical loads of the manual drilling process. The tool geometry and set configuration of one out of five implant drill sets appears to be superior regarding chip mass, vitality, and thrust force. It could be proven that there is a correlation between vitality and thrust force. The thrust force is influenced by the cutting behavior of the tool, which in turn depends on the geometry of the tool. The tool geometry has an influence on the vitality of the augmentation material due to this relationship.

Biomechanical Evaluation of Mandibular Condyle Fracture Osteosynthesis Using the Rhombic Three-Dimensional Condylar Fracture Plate.

PURPOSE: The aim of the present study was to evaluate the biomechanical stability of osteosynthesis in mandibular condyle fractures using a newly designed rhombic 3-dimensional (3D) condylar fracture plate and compare it with that using standard two 4-hole miniplates and with that in nonfractured condyles. MATERIALS AND METHODS: Using 200 porcine mandibles, 3 different monocortical plating techniques were evaluated. The condyles were fractured along a defined line tangentially through the sigmoid notch and perpendicular to the posterior border. After anatomic reduction, osteosynthesis was performed using either standard rhombic 3D condylar fracture plates and standard screws (group A) or locking rhombic 3D condylar fracture plates, which were fixed either with standard screws (group B) or locking screws (group C). For comparison, nonfractured condyles (group D) and condyles fixed with standard two 4-hole miniplates and 8 screws (group E) were included. Using a universal mechanical testing machine (TIRA Test 2720; TIRA GmbH Schalkau, Germany), each group was subjected to linear loading from laterally to medially, medially to laterally, anteriorly to posteriorly, and posteriorly to anteriorly. The maximum axial force and displacement at the maximum force were measured. The mean values were compared for statistical significance using analysis of variance with Bonferroni's correction (statistical significance set at P < .05). RESULTS: The main mode of failure in the plating techniques investigated was the pull out of screws from the proximal fragment. We found no statistically significant differences in the stability of osteosynthesis between the two 4-hole miniplates and the rhombic 3D condylar fracture plate when loading from posteriorly to anteriorly, laterally to medially, and medially to laterally. However, when loading from anteriorly to posteriorly, a statistically significant difference between the standard and locking system and the two 4-hole miniplate system was observed, with the latter proving more stable. CONCLUSIONS: The results of the present biomechanical study suggest that the rhombic 3D condylar fracture plates are suitable for the treatment of condylar neck fractures. Both types of the plate are able to resist physiologic strains comparable to the two 4-hole miniplates.