International Journal of Computerized Dentistry, 03/2009

Apart from monographs, textbook publications and publications on websites, scientific studies have also been published concerning the method of condyle position analysis. Determination of the current research status, which can serve as basis for further scientific publications, would therefore be helpful. Accessing the texts published on this subject in scientific journals is comparatively difficult, since a keyworded search term by which the subject area can be narrowed down directly is not available in the "Medline" database. The development of a computerassisted bibliographical search matrix, which facilitates clear identification of relevant publications in scientific journals through "Medline", is described in this paper as an example. This search matrix can be used in corresponding web services and can also be imported into research software and saved for future computer-assisted searches. The currently available scientific studies on condyle position analysis have been found and structured with regard to contents on the basis of the search matrix and with the aid of other research sources. The matrix describing the structure of the contents serves as a logical classification on the basis of which the publications have been classified. In addition to the classification by subject, the evidence levels were determined for the scientific studies - on the basis of their concept - and thus the external evidence on condyle position analysis as a procedure was developed. Keywords: condyle position, literature research, retrieval/search strategy, levels of evidence

Condylar position analysis is a measuring method for the three-dimensional quantitative acquisition of the position of the mandible in different conditions or at different points in time. Originally, the measurement was done based on a model, using special mechanical condylar position measuring instruments, and on a research scale with mechanical-electronic measuring instruments. Today, as an alternative, it is possible to take measurements with electronic measuring instruments applied directly to the patient. The computerization of imaging has also facilitated condylar position measurement by means of threedimensional data records obtained by imaging examination methods, which has been used in connection with the simulation and quantification of surgical operation results. However, the comparative measurement of the condylar position at different points in time has so far not been possible to the required degree. An electronic measuring instrument, allowing acquisition of the condylar position in clinical routine and facilitating later calibration with measurements from later examinations by data storage and use of precise equalizing systems, was therefore designed by the present authors. This measuring instrument was implemented on the basis of already existing components from the Reference CPM und Cadiax Compact articulator and registration systems (Gamma Dental, Klosterneuburg, Austria) as well as the matching CMD3D evaluation software (dentaConcept, Hamburg). Keywords: quantitative measurement of jaw position, condylar position analysis, equalizing systems, electronic measuring device, centric relation records, dimensional stability of bite-record materials

Purpose: Condylar position analysis facilitates a quantitative comparison of the condylar position with and without a bite record, different records and changed influencing factors. Handling by the examiner when positioning the model is a significant factor with regard to the accuracy of the examination. Measurement accuracy could be improved when positioning the models by using special working bites, hence the objective of the experiments described in this study consisted in examining the extent to which the measuring results are influenced by different examiners and by using working bites. Materials and Methods: In the first trial, one examiner performed ten measurements without and with an interposed working bite for five model pairs in each case. In the second trial, nine examiners (three specialized dentists, three dental assistants, three students) performed ten measurements in each case without and with an interposed working bite. The three-dimensional position was read digitally with the E-CPM (Gamma Dental, Klosterneuburg/Vienna, Austria), recorded by means of spreadsheet software (Microsoft Excel) and diagnostic software (CMDfact, CMD3D module, dentaConcept, Hamburg), and evaluated with graphing software (Sigma Plot, Systat Software, USA). Results: In the first trial, it was shown that the reproducibility of mounting was improved markedly (p 0.01) by using bite records in the form of working bites. In the second trial, it was shown that the mean error increased significantly (p 0.01) when several examiners performed the measurements compared with the results of one examiner alone. No significantly different results occurred (p 0.01) in the comparison of the different groups of examiners with different educational and training backgrounds. This applied for the mounting methods without and with working bite. On the other hand, the reproducibility of mounting improved distinctly (p0.01) in every group of examiners when working bites were used. Conclusions: Reproducibility of condylar position analysis was improved significantly by mounting the models with special working bites. This applied for operators of different professional background (dentists, dental assistants and dental students), while there were no significant differences between results of the three groups. Keywords: quantitative measurement of the jaw position, condylar position analysis, equalizing systems, electronic measuring instrument, centric records, influence of working bites on condylar position analysis

Purpose: The aim of the present study was to evaluate the reliability and re-producibility of digital shade selection devices, and to correlate the results with conventional human visual shade assessment. Materials and Methods: Tooth color gradation and agreement of two different digital shade selection instruments were determined by employing a spectro-photometer (ShadePilot, Degudent; Hanau, Germany, Software V. 2.41) and a colorimeter (ShadeVision, Ammann Girrbach; Pforzheim, Germany; Software V. 1.20). The devices were compared with three human examiners with a negative history of visual color deficiency, looking at 40 subjects under clinical conditions. In one half of the test persons, the visual and digital shade determination was performed on the right maxillary central incisor that was free of any restoration, whereas the other half was carried out in subjects with single implant-supported PFM crowns in the same region. The computer-based readings across the regions (incisal, middle, cervical) were recorded two consecutive times. Differences between the computer-based readings were evaluated with the χ2 test (Chi-square). Results: The same shade was obtained by all three human examiners in 22.5% (9 of 40 cases), by all colorimetric readings in 35% (14 of 40 cases), and by all spectrophotometric readings in 55% (22 of 40 cases). There was considerable agreement between the first and second reading of the investigated spectrophotometric and colorimetric shade instruments. The spectrophotometer demonstrated color matches of the first and second reading in 81.7% of the in vivo measurements (coefficient of contingency = 0.98; χ2 test p = 0.99), while the colorimeter exhibited matches in 70% (coefficient of contingency = 0.96; χ2 test p = 0.96) of the cases. Hence, the spectrophotometer exhibited the highest agreement between the two consecutive readings. While no significant influ-ence of the measuring point (incisal, middle, cervical) on the reproducibility of color results could be ascertained, both the colorimeter and spectrophotometer displayed a statistically significant difference for the frequency distribution of color categories for teeth vs PFM crowns (both χ2 test p 0.0001). The measuring results of the colorimeter showed distinctly lighter shades than those of the spectrophotometer. Conclusions: Within the limitations of this study, the results suggest that spectrophotometric shade determination is more reproducible compared to conventional visual shade assessment. It can serve as a reliable addition in color matching and enhances the level of shade analysis, communication, interpretation, and fabrication of dental restorations. Keywords: shade determination, spectrophotometric, colorimetric, visual human, measurement agreement, implant crown

The objective of the present study was to determine the clinical success of Cerec 3D inlays over a period of three years. Within the scope of the restorative dentistry course II, 62 Cerec ceramic inlays were inserted with Dual Cement (Ivoclar Vivadent) in combination with the Syntac Classic system (Ivoclar Vivadent). Regular follow-up examinations and assessments were performed by reference to modified US Public Health Service (USPHS) criteria. The baseline examination was performed one week after insertion and further follow-up examinations were performed at 6-month intervals. The survival rate of the Cerec 3D inlays was 95% after three years. Three inlays were assessed as failures because of loss of sensitivity, restoration fracture, and marginal gap formation. Six patients initially suffered from postoperative hypersensitivity, which vanished by the first follow-up examination. The results of this study show that dentists with little experience are able to achieve good clinical results and long-term success after short theoretical as well as practical training and an introductory course in the Cerec method. Keywords: CAD/CAM, Cerec 3D system, ceramic inlays, student training

Apart from precision, the time factor plays a decisive role in the fabrication of all-ceramic dental restorations. Therefore, the aim of this study was to compare two all-ceramic systems with regard to the time required for the fabrication of partial crowns [MODB]. The null hypothesis tested was that the fabrication times of CAD/CAM generated partial crowns are shorter than the fabrication times of partial crowns manufactured in the laboratory. Materials and Methods: In sixteen model pairs mounted in the articulator, which corresponded to different clinical situations, tooth 36 was prepared for an all-ceramic partial crown [MODB]. With the Cerec3D method [CHAIR], the fabrication of the restoration was simulated directly on the "phantom patient". The IPS Empress system [LAB] was used for the indirect fabrication method via an impression of the phantom patient. Both methods were used for each preparation. The adhesive luting procedure was not simulated and, therefore, not measured. Results: The mean processing times [hh:mm:ss] were 00:35:05 (SD ± 03:27 min) for the Cerec method and 04:17:54 (SD ± 26:01 min) for the Empress method. The mean time on the phantom patient for process-induced activities was 11:47 minutes (SD ± 02:08 min) for the Cerec method and 03:58 minutes (SD ± 02:50 min) for the Empress method. Discussion: Time expenditure for fabrication is only one aspect in order to assess the suitability of a restoration system. Both methods enable the dentist to provide high quality all ceramic restorations. Although the Empress method showed a time advantage of 65% during the fitting phase and occlusal grinding-in on the phantom patient in comparison to the Cerec method, the time spent during the laboratory phase has to be considered as well. Keywords: time expenditure, Cerec 3D, IPS Empress, partial crown, onlay, ceramic materials