Passive method for 3D reconstruction of human jaw: theory and application.

Oral dental applications based on visual data pose various challenges. There are problems with lighting (effect of saliva, tooth dis-colorization, gum texture, and other sources of specularity) and motion (even inevitable slight motions of the upper/ lower jaw may lead to errors far beyond the desired tolerance of sub-millimeter accuracy). Nowadays, the dental CAM systems have become more compromised and accurate to obtain the geometric data of the jaw from the active sensor (laser scanner). However, they have not met the expectations and the needs of dental professionals in many ways. The probes in these systems are bulky { even their newer versions - and are hard to maneuver. It requires multiple scans to get full coverage of the oral cavity. In addition, the dominant drawback of these systems is the cost. Stereo-based 3D reconstruction provides the highest accuracy among vision systems of this type. However, the evaluation of it\u27s performance for both accuracy results and the number of 3D points that are reconstructed would be affected by the type of the application and the quality of the data that is been acquired from the object of interest. Therefore, in this study, the stereo-based 3D reconstruction will vi be evaluated for the dental application. The handpiece of sensors holder would reach to areas inside the oral cavity, the gap between the tooth in the upper jaw and the tooth in the lower jaw in these areas would be very small, in such the stereo algorithms would not be able to reconstruct the tooth in that areas because of the distance between the optical sensors and the object of interest \tooth as well as the configuration of optical sensors are contradicted the geometric constraint roles of the stereo-based 3D reconstruction. Therefore, the configuration of the optical sensors as well as the number of sensors in the hand piece of sensors holder will be determined based on the morphological of the teeth surfaces. In addition to the 3D reconstruction, the panoramic view of a complete arch of human teeth will be accomplished as an application of dental imaging. Due to the low rate of features on teeth surfaces, the normal tooth surface is extracted using shape from shading. The extracted surface normals impact many imprecise values because of the oral environment; hence an algorithm is being formulated to rectify these values and generate normal maps. The normal maps reveal the impacted geometric properties of the images inside an area, boundary, and shape. Furthermore, the unrestricted camera movement problem is investigated. The camera may be moved along the jaw curve with different angles and distances due to handshaking. To overcome this problem, each frame is tested after warping it, and only correct frames are used to generate the panoramic view. The proposed approach outperforms comparing to the state-of-art auto stitching method

An In Vitro Investigation of a Novel, Two-Piece Zirconia Dental Implant System

Implant treatment is currently overriding other prosthetic solutions especially in the case of replacing anterior teeth in the aesthetic zone. Zirconia ceramics exhibit promising aesthetic, periointegration and antibacterial properties that may overcome critical drawbacks associated with titanium based dental implants. They also possess distinctive mechanical properties due to the unique transformation toughening mechanism. However, the effects of low-temperature degradation (LTD) or ageing on the durability of the material is of a major concern. Additionally, the currently available one-piece and two-piece zirconia dental implant designs exhibit sub-standard performance. This study aimed to investigate ageing, mechanical properties and biofunctional characteristics of a new implant system with a novel biomechanical design. The proposed design utilises a relatively low-strength glass fibre composite abutment bonded with resin cement to an injection-moulded, soft tissue level, acid-etched zirconia implant. Hydrothermal treatment was used to simulate in vivo ageing. A battery of complimentary crystallographic and imaging studies was used to characterise hydrothermally- and stress-induced phase transformation. Additionally, the effect of ageing on basic mechanical properties of standard samples was investigated at the macro-, micro- and nano-scales. Dynamic fatigue was performed in order to determine durability and reliability of various components and interfaces of the design under simulated clinical conditions. The acid-etched zirconia surface (MDS) was compared to a high-performance, mechanically and chemically modified titanium surface in terms of; surface topography, biocompatibility and cell biofunctional response. The results of this study indicated that hydrothermal ageing resulted in phase transformation that was localised to the surface of the material without any involvement of the bulk. No evidence of extensive cracking was detected as a result of the used ageing conditions. The aged samples exhibited static mechanical properties that were not significantly different from the control group apart from marginal decreases in surface hardness. The implant samples restored with two different crown materials did not exhibit any premature failures. The engineered weak connection seemed to favour retrievable failures especially when low strength crown material was used to restore the implants. The studied MDS zirconia surface exhibited moderate surface roughness and high biocompatibility when tested with human osteoblast-like cells and human gingival fibroblasts. Cell attachment and bone formation capacity of cells were similar or marginally higher in cells cultured on MDS surface when compared to titanium (SLActive-like) counterpart. Within the limitations of this study, it can be concluded that the studied zirconia material was not drastically affected by hydrothermal ageing and thereby, in vivo LTD may be not of a concern whilst using such material. The current implant design may withstand long-term functional forces in the anterior region of the oral cavity. The MDS surface may reduce the time required for bone and soft tissue healing which is essential for clinical cases require immediate provisionalisation and/or early loading. Soft tissue remodelling may be of a less concern owing to the high soft tissue attachment (periointegration) capacity of the studied MDS zirconia surface

Applications of EMG in Clinical and Sports Medicine

This second of two volumes on EMG (Electromyography) covers a wide range of clinical applications, as a complement to the methods discussed in volume 1. Topics range from gait and vibration analysis, through posture and falls prevention, to biofeedback in the treatment of neurologic swallowing impairment. The volume includes sections on back care, sports and performance medicine, gynecology/urology and orofacial function. Authors describe the procedures for their experimental studies with detailed and clear illustrations and references to the literature. The limitations of SEMG measures and methods for careful analysis are discussed. This broad compilation of articles discussing the use of EMG in both clinical and research applications demonstrates the utility of the method as a tool in a wide variety of disciplines and clinical fields

Medical-Data-Models.org:A collection of freely available forms (September 2016)

MDM-Portal (Medical Data-Models) is a meta-data repository for creating, analysing, sharing and reusing medical forms, developed by the Institute of Medical Informatics, University of Muenster in Germany. Electronic forms for documentation of patient data are an integral part within the workflow of physicians. A huge amount of data is collected either through routine documentation forms (EHRs) for electronic health records or as case report forms (CRFs) for clinical trials. This raises major scientific challenges for health care, since different health information systems are not necessarily compatible with each other and thus information exchange of structured data is hampered. Software vendors provide a variety of individual documentation forms according to their standard contracts, which function as isolated applications. Furthermore, free availability of those forms is rarely the case. Currently less than 5 % of medical forms are freely accessible. Based on this lack of transparency harmonization of data models in health care is extremely cumbersome, thus work and know-how of completed clinical trials and routine documentation in hospitals are hard to be re-used. The MDM-Portal serves as an infrastructure for academic (non-commercial) medical research to contribute a solution to this problem. It already contains more than 4,000 system-independent forms (CDISC ODM Format, www.cdisc.org, Operational Data Model) with more than 380,000 dataelements. This enables researchers to view, discuss, download and export forms in most common technical formats such as PDF, CSV, Excel, SQL, SPSS, R, etc. A growing user community will lead to a growing database of medical forms. In this matter, we would like to encourage all medical researchers to register and add forms and discuss existing forms