PubMed ID (PMID): 26389133Pages 201-223, Language: English, GermanAhlers, M. Oliver / Bernhardt, Olaf / Jakstat, Holger A. / Kordaß, Bernd / Türp, Jens C. / Schindler, Hans-Jürgen / Hugger, Alfons
Mandibular movement recording has long been established as the method for the physiological design of indirect dental restorations. Condylar movement recording is the basis for individual, patient-specific programming of partially or fully adjustable articulators. The settings derived from these recordings can generally be used in both traditional mechanical and electronic virtual articulators. For many years, condylar movement recordings have also provided useful information about morphological conditions in the temporomandibular joints (TMJs) of patients with masticatory system dysfunction based on the recorded movement patterns. The latest clinical application for recorded jaw-motion analysis data consists of functional monitoring of the patient as a diagnostic and surveillance tool accompanying treatment. Published parameters for the analysis of such recordings already exist, but a standardized and practicable protocol for the documentation and analysis of such jaw-movement recordings is still lacking. The aim of this article by a multicenter consortium of authors is to provide an appropriate protocol with the documentation criteria needed to meet the requirements for standardized analysis of computer-assisted recording of condylar movements in the future.
Keywords: diagnosis, mandibular condyle, mandibular movement recordings, range of motion, reference standards, temporomandibular joint
PubMed ID (PMID): 26389134Pages 225-235, Language: English, GermanKordaß, Bernd / Ruge, Sebastian
Analysis of temporomandibular joint (TMJ) function using condylar path tracings is a challenge in functionally oriented dentistry. In most cases, reference points on the skin surface over the TMJ region are defined as "arbitrary", "individual" or "kinematic" condylar hinge axis points, which are displayed as "condylar paths" in motion. To what extent these reference points represent the actual condylar paths in each individual patient is ultimately unclear because the geometric relationship of the actual condyle to the selected reference point is usually unknown. Depending on the location of the point on the condyle and the centers of rotation of mandibular movement, these trajectories can vary greatly during combined rotational and sliding movements (eg, opening and closing movements of the mandible); this represents a grid of points located in the vicinity of the TMJ. To record the actual condylar path as the movement trajectory of a given point (eg, the condylar center), technological solutions are needed with which to link the tracing technology with the appropriate imaging technology capable of scanning the condyle, including the points of interest, and displaying them in real dynamic motion. Sicat Function (Sicat, D-Bonn) is such a solution. Sicat Function links cone beam computed tomography (CBCT) scans (made using the Galileos CBCT scanner; Sirona, Bensheim, Germany) with ultrasound-based, three-dimensional (3D) functional jaw movement recordings of the mandible (made using the JMT+ Jaw Motion Tracker; Sicat, Bonn, Germany). Digital images of the dental arches acquired with the intraoral scanner Cerec system (Sirona) can also be superimposed. This results in the generation of a 3D model of the bony mandible, including the TMJ, which reproduces the 3D real dynamic movement of the condyles simultaneously with that of the condylar paths at defined points (with the condylar centers being a particular point of interest). Sicat Function is an integrated, digital 3D solution for additional instrumental and imaging diagnosis of temporomandibular joint dysfunction (TMD). The primary indication for Sicat Function is persistent, arthrogenic TMD complaints that require additional studies for evaluation of bony structural components of the TMJ.
Keywords: Sicat Function, cone beam computed tomography (CBCT), functional analysis, condyle movement, TMJ diagnosis, TMD
PubMed ID (PMID): 26389135Pages 237-258, Language: English, GermanPascale, Andra Maria / Ruge, Sebastian / Hauth, Steffen / Kordaß, Bernd / Linsen, Lars
Nowadays, CAD/CAM software is being used to compute the optimal shape and position of a new tooth model meant for a patient. With this possible future application in mind, we present in this article an independent and stand-alone interactive application that simulates the human chewing process and the deformation it produces in the food substrate. Chewing motion sensors are used to produce an accurate representation of the jaw movement. The substrate is represented by a deformable elastic model based on the finite linear elements method, which preserves physical accuracy. Collision detection based on spatial partitioning is used to calculate the forces that are acting on the deformable model. Based on the calculated information, geometry elements are added to the scene to enhance the information available for the user. The goal of the simulation is to present a complete scene to the dentist, highlighting the points where the teeth came into contact with the substrate and giving information about how much force acted at these points, which therefore makes it possible to indicate whether the tooth is being used incorrectly in the mastication process. Real-time interactivity is desired and achieved within limits, depending on the complexity of the employed geometric models. The presented simulation is a first step towards the overall project goal of interactively optimizing tooth position and shape under the investigation of a virtual chewing process using real patient data (Fig 1).
Keywords: CAD/CAM, Cerec, chewing, deformable model, substrate
PubMed ID (PMID): 26389136Pages 261-271, Language: English, GermanKooistra, Ronald
Hin und wieder verfärben sich Schneidezähne aufgrund von Traumata. In den meisten Fällen bedingt das Trauma komplizierte Dentin- und Schmelzfrakturen, die eine sofortige restaurative Behandlung notwendig machen. In manchen minderschweren Fällen ist das Trauma geringfügig und führt nicht zu strukturellen Schäden an der Zahnhartsubstanz. Das Pulpagewebe reagiert aber dann mit Verfärbungen auf das Trauma. In den folgenden beiden Frontzahnfällen sind am Apex der Schneidezähne jeweils keine Veränderungen sichtbar. Es ist anzunehmen, dass das Pulpagewebe bis zu einem gewissen Grad vital bleibt und dass die Pulpa auf mehrere Arten auf das Trauma reagieren kann. In beiden besprochenen Beispielen ist eine Farbveränderung am mittleren Schneidezahn in Verbindung mit einer Unregelmäßigkeit bei der Frontzahnstellung sichtbar. Die Patienten hatten den expliziten Wunsch, die Farbe des dunkleren Schneidezahns zu verändern, um wieder ein harmonisches Lächeln zu erzielen.
Keywords: noninvasive Veneers, IPS e.max CAD, Cerec Ästhetik
Open AccessPubMed ID (PMID): 26389137Pages 273-286, Language: English, GermanBosch, Gabriel / Ender, Andreas / Mehl, Albert
Abrasion und Erosion sind zwei immer wichtiger werdende Ursachen für eine zahnmedizinische Behandlung. Dank moderner digitaler Technik und neuen Materialien lassen sich solche Substanzverluste nahezu noninvasiv nach neuen Konzepten versorgen. Anhand einer Kasuistik wird solch ein neues Konzept dargestellt. Ein Patient mit stark abradierter Eigenbezahnung wurde defektorientiert und möglichst noninvasiv mit Hochleistungskomposit im Seitenzahnbereich und der "Sandwich-Technik" im Frontzahnbereich versorgt. Die Restaurationen wurden auf einer Schleifmaschine ausgeschliffen, die für passgenaue und dünn auslaufende Restaurationen optimiert ist.
Keywords: Bisshebung, ultradünne okklusale Veneers, Hochleistungskomposit, noninvasiv, virtuelle Artikulation, CAD/CAM, komplexe Rehabilitation