PubMed ID (PMID): 22891414Pages 93-107, Language: English, GermanKordaß, Bernd / Hugger, Alfons / Bernhardt, Olaf197 subjects (74 male, 123 female) were evaluated in this Study of Health in Pomerania associated project (SHIP 0). Both a clinical functional status and an instrumental analysis of functional movement patterns of the mandible were performed in each subject, in the latter case using an ultrasonic jaw motion analysis system. Correlations between instrumental movement pattern features and clinical signs and symptoms of temporomandibular joint dysfunction (TMD), such as joint sounds, palpable impairment of jaw movement, and the termination of opening movement at the incisal point, were particularly significant (p 0.005). Correlations for TMJ crepitation sounds and joint pain on palpitation from the lateral or posterior aspect tended to be less significant (p 0.1). No association was found for pain on jaw movement or muscle tenderness in response to pressure. A multivariate logistic regression model showed a significant correlation between Helkimo Clinical Dysfunction grades 2 and 3 and the following independent variables: frequent headaches (odds ratio [OR] 4.12; p = 0.032), frequent popping sounds in the jaw joints (OR 5.79; p = 0.012), incisal paths showing conspicuous signs of dysfunction such as deviation or deflection (OR 4.35; p = 0.05), and condylar path anomalies such as jumpy, straight/inverse or irregular tracings (OR 28.59; p = 0.006). Instrumental functional analysis of condylar path tracings allows one to draw statistically valid conclusions about the occurrence of TMD symptoms. It can be helpful to perform condylar path analysis when performing risk assessments for temporomandibular dysfunction in certain situations, particularly before prosthetic rehabilitation.
Keywords: temporomandibular joint dysfunction, TMD, craniomandibular dysfunction, CMD, instrumental functional analysis, temporomandibular disorders, jaw motion analysis, three-dimensional jaw tracking
PubMed ID (PMID): 22891415Pages 109-123, Language: English, GermanMehl, AlbertMajor advances have been made in dental computer-assisted design and manufacturing (CAD/CAM) technology in recent years. New developments in intraoral optical scanning systems make it possible to rapidly obtain three-dimensional images and measurements of the jaw and entire quadrants, including the prepared teeth, neighboring teeth, and opposing dentition. In addition, the static relationship of the maxillary and mandibular teeth to one another can easily be determined by means of intraoral bite registrations or buccal scans. This information is the starting point for the implementation of digital occlusal surface design and surface reconstruction. Here, too, the knowledge-based concept of biogenerics has crystallized into a new method in which restoration proposals suitable for each individual case are automatically computed by the software. Consequently, the time required to manually edit the digital model has been significantly reduced or completely eliminated. In its current form, the digital workflow still lacks a strategy for integrating the dynamic occlusion into the restoration design with high precision and in a time-saving manner. The preliminary results of new digital concepts and approaches to solving this problem will be presented in this article.
Keywords: Virtual articulation, functional bite registration, functionally generated path, virtual FGP, average-value articulation
PubMed ID (PMID): 22891416Pages 125-136, Language: English, GermanTsitrou, Efrosyni / Tsangaria, Kyriaki N.Purpose: To examine the performance of CAD/CAM allceramic resin-bonded bridges (RBBs) fabricated from a glass ceramic material, and determine the influence of two different preparation designs on the fracture strength of these prostheses.
Materials and Methods: Twenty human central incisors were used, placed into two groups. A clinical situation where a lateral incisor was missing was simulated. A minimal preparation design (palatal veneer preparation) and one that extended into the proximal area were applied in each group. The Cerec InEos and the Cerec 3D software were used to scan, design, and mill the restorations. A lithium disilicate glass ceramic material was used for the fabrication of the bridges (IPS e.max CAD). Twenty bridges were milled which were adhesively bonded on their abutments (Variolink II). A universal testing machine was used to evaluate the fracture strength and the mode of failure of the bridges.
Results: The mean fracture strength for the minimal design group was 774 N (± 341) and for the extended preparation group 814 N (± 474). No statistically significant difference was found between the two designs (p > 0.05). The mode of failure was fracture at the connector area between the pontic and the retainer wing.
Conclusion: The fracture strength of the RBBs fabricated with IPS e.max CAD was in a clinically acceptable range. The two preparation designs did not have a significant influence on the fracture strength of the RBBs.
Keywords: resin bonded bridge, Cerec, lithium disilicate, fracture strength, kompositverklebte Brücke, Cerec, Lithiumdisilikat, Bruchfestigkeit
PubMed ID (PMID): 22891419Pages 159-164, Language: English, GermanKoller, Martin / Arnetzl, Gerwin V. / Holly, L. / Arnetzl, GerwinLava Ultimate Resin Nano Ceramic (RNC) blocks are innovative new CAD/CAM materials that make it possible to achieve superior esthetic results in easy steps. The blocks are made of nano ceramic particles embedded in a highly cured resin matrix. Therefore, composite materials can be used to characterize and adjust resin nano ceramic restorations after milling. The milled RNC restorations can be individualized intra-orally or extra-orally, either before or after insertion. Unlike conventional ceramic restorations, customization and glaze firing is neither necessary nor possible with RNC restorations. This opens up the opportunity for intraoral individualization and adaptation of the restorations.
