International Journal of Computerized Dentistry, 02/2011

The increased availability of devices for 3D radiological diagnosis allows the more frequent use of CAD/CAMproduced surgical guides for implant placement. The conventional workflow requires a complex logistic chain which is time-consuming and costly. In a pilot study, the workflow of directly milled surgical guides was evaluated. These surgical guides were designed based on the fusion of an optical impression and the radiological data. The clinical use showed that the surgical guides could be accurately placed on the residual dentition without tipping movements. The conventional surgical guides were used as a control for the manual check of the deviation of the implant axis. The direct transfer of the digital planning data allows the fabrication of surgical guides in an external center without the need of physical transport, which reduces the logistic effort and expense of the central fabrication of surgical guides. Keywords: digital workflow, 3D diagnosis, cone-beam CT, digital implant planning, guided implant placement, telemedicine, reduced logistics, image fusion

The following article describes a method for the clinical depiction and documentation of the strength, extent, and location of occlusal contact areas on the basis of digitized bite records. Bite records made of low-viscosity, additioncured silicone in centric occlusion are digitized in a document scanner using incident and transmitted light scanning. Layer thicknesses = 20 µm were interpreted as occlusal contacts and classified as belonging to the anatomical structures of the occlusal surfaces. This procedure is of particular significance for epidemiological studies, but also of interest for dental practices and laboratories, since it can be used as a simple method of continuous quality control, documentation, and archiving of the patient's current occlusal contact situation. Keywords: occlusion, centric occlusion, digital occlusion, virtual articulator, contact point analysis

Introduction: Magnetic resonance imaging (MRI) has been approved as an appropriate radiological modality for temporomandibular joint (TMJ) diagnosis, whereas the results of international multicenter studies impressively show the limitations of static three-dimensional MRI. The state of the art for dynamic imaging of the TMJ in real-time are TrueFISP sequences in one sagittal plane. In order to support the diagnostics, a computer-assisted visualization procedure has been developed by the authors for both the static and dynamic MRI. Methods: A number of validated sequences are available for the static 3D-MRI within the clinical routine. For dynamic MRI in real-time, True-FISP sequences in one sagittal plane with a slice thickness of 5-10 mm and 1.3 mm × 1.3 mm spatial resolution were applied. Both the dynamic and static MRI datasets are animated and visualized using the computer- assisted procedure. Results: The computer-assisted procedure reliably supported the clinical diagnosis, especially the visibility of the articular disc was enhanced. On the basis of the static MRI, a 60-year-old patient was diagnosed with anterior disc displacement without reduction. In contrast, by the dynamic MRI, it was recognized how the articular disc was firstly somehow stretched and flattened before the mandibular condyle again glided under the disc, thus resulting in an anterior disc displacement with reduction. Conclusion: These results endorse the relevance of realtime diagnosis for the TMJ. The computer-assisted visualization has been approved as a reliable help for clinical diagnosis. Keywords: temporomandibular joint, articular disc, anterior disc displacement with reduction, anterior disc displacement without reduction, MRI, dynamic MRI, real-time imaging, computer-assisted visualization, direct volume rendering

Virtual articulation makes it possible to overcome the limitations of mechanical articulation. Novel visualization techniques have great advantages. In this study, the occlusal surfaces of the upper and lower teeth were digitized with a 3D scanner, and real functional movements of the mandible were recorded using the Jaw Motion Analyzer (JMA), an ultrasonic measurement system. A coupling component designed for clinical use in the patient's mouth was utilized for precise referencing of the movement and scan data. Similar to a two-sided impression tray, the coupling tray is used to take a joint impression of the upper and lower arches. The JMA records the positions of the mandible and the coupling component in space. The virtual articulator was designed for visualization of jaw relationships during mastication. For analysis of intercuspation, the system generates dynamic images on which closing movements/ dynamic occlusion and contact areas are highlighted. The jaw movement data are plotted to create an envelope surface representing the maximum possible space occupied by the mandible. Such an envelope surface is a type of virtual FGP (functionally generated path) bite registration. It can be applied to design virtual tooth restorations and helps to quantify the occlusal space in a virtual environment. This system can be used to individually register and utilize the variability of occlusal function. Keywords: virtual articulator, virtual occlusion, dynamic occlusion, occlusal contacts, occlusion, variability

Amelogenesis imperfecta refers to a hereditary dysplasia of the enamel. As a result of various defects, qualitatively and/ or quantitatively abnormal enamel forms, while the dental structure remains normal. The following article describes the condition and presents the case of an 8-year-old boy who was dentally reconstructed both functionally and aesthetically using the adhesive technique and machinable high performance polymer restorations. Keywords: Cerec, CAD/CAM technology, Amelogenesis imperfecta, hereditary enamel defects, high performance polymers

The Cerec InLab software 3.80 allows for the fabrication of implant abutments and crowns without taking impressions. The intraoral optical impression is taken with the help of what is termed "scanbodies". The custom-made zirconia abutments are bonded to a titanium base and can thus be fastened with high torques without creating tensile stress. Keywords: abutments, zirconia, superstructure, titanium base

The way we collect, store, and share dental records of our patients is rapidly becoming digital. Many programs have been designed to run on a single computer or local network to handle various tasks, so selecting a system can be complex; it can require high acquisition costs, update fees, and installation difficulties. The purpose of this article is to explain the architecture, characteristics, and advantages related to Web-based Management Software. In particular, this article describes the first Web-based Electronic Medical Record (DocSapiens.com), which is able to view and edit DICOM files directly online. Keywords: software, management, managing, Internet, EMR, DICOM

Dentistry and dental engineering today are characterized by rapid developments in the sectors of digital dentistry as well as new materials and methods. The effective management of new workflows is at the same time a challenge and a source of motivation for the entire practice or laboratory team.