PURPOSEThe newest technologies for digital implant impression (DII) taking are developing rapidly and showing acceptable clinical results. However, scientific literature is lacking data from clinical studies about the accuracy of DII. The aim of this study was to compare digital and conventional dental implant impressions (CII) in a clinical environment.MATERIALS AND METHODSTwenty-four fixed zirconia restorations supported by 2 implants were fabricated using conventional open-tray impression technique with splinted transfers (CII group) and scan with Trios 3 IOS (3Shape) (DII group). After multiple verification procedures, master models were scanned using laboratory scanner D800 (3Shape). 3D models from conventional and digital workflow were imported to reverse engineering software and superimposed with high resolution 3D CAD models of scan bodies. Distance between center points, angulation, rotation, vertical shift, and surface mismatch of the scan bodies were measured and compared between conventional and digital impressions.RESULTSStatistically significant differences were found for: a) inter-implant distance, b) rotation, c) vertical shift, and d) surface mismatch differences, comparing DII and CII groups for mesial and dist al implant scan bodies (P≤.05).CONCLUSIONRecorded linear differences between digital and conventional impressions were of limited clinical significance with two implant-supported restorations.

Companies are interested in retaining workers healthy, productive, and satisfied while cutting health-care and insurance costs. Using a computer at work can cause back, neck and shoulder pain, eyestrain, and overuse injuries of human hands and wrists. It is possible to reduce these risks with better posture and good habits, such as taking rest breaks. During these breaks computer users should be encouraged to stand, stretch, and move around. For people who forget about a break or truly are focused on their direct work need help from special equipment for evaluation of real physical activity of computer user. Method for recording accelerometer data from moving human as he or she performs daily activities and for identification of type, duration and intensity of movements by using wearable wireless sensing system is presented in this paper. The extraction of orientation independent acceleration data has positive effect on recognition accuracy of k-nearest neighbour classification scheme used for classification task. The recognition accuracy of algorithm is 78.9% and these results are better than accuracy obtained from raw accelerometer data. The method presented is simple, exhibited good performance and does not require significant computational recourses.

Objectives: To evaluate thermal images (TIs) by using an algorithm for optimized region of interest (ROI) and image segmentation, in order to find zones of the facial skin surface with asymmetrical temperature, and to test consistency with CT findings, to detect maxillofacial pathologies (i.e. tumours). Methods: The following steps for the TI evaluation were applied: data acquisition/pre-processing of frontal face and mouth projection, detection of face and mouth external contour, finding face and mouth symmetry axis, calculation of differences in average and maximal temperatures between left and right face and mouth sides, image segmentation of the selected ROI, and evaluation of diagnostic accuracy by comparing the TI results with CT findings. Results: In healthy subjects, the average temperature difference between left/right sides of facial and mouth ROI was negligible (0.02 ± 0.21 °C and 0.05 ± 0.19 °C, respectively; n = 23). In the presence of tumour, the average temperature difference was higher in corresponding TIs (0.47 ± 0.1 °C and 0.66 ± 0.1 °C, for facial and mouth ROI, respectively; n = 19, p < 0.05). For large tumours, thermal asymmetry in the corresponding TI is easily detected, and image segmentation is optional for finding the affected zone. For small or deeply localized tumours, segmentation of the mouth cavity of the ROI was required for the detection of hot and cold spots. conclusions: Asymmetrical temperature zones and their location as detected from thermal images coincide well with the presence and localization of maxillofacial pathologies (i.e. tumours) established by CT. However, accurate information could often be obtained only after application of image segmentation algorithm to the selected ROI.

Aim of our study is to develop a method for the experimental identification of the settings of a computed tomography (CT) scanner used for scanning of human jaw. I this case, CT can be used for rapid prototyping of human jaw, design and manufacture of implants. The experimental identification of settings of a computed tomography scanner is done by comparing 3D computer models built using different data acquisition technologies: CT scanner and 3D laser scanner. The modified Iterative Closest Points algorithm is used for alignment of 3D computer models, obtained using different scanning methods. The different test objects were scanned using a spiral CT scanner and 3D laser scanner for testing the method. 3D computer models were compared uding the mean square value of distance between two surfaces. The test results indicate hardware and software parameters impacting on the accuracy and surface quality of 3D computer model reconstructed from CT data. Ill. 5, bibl. 7 (in English; abstracts in English and Lithuanian).http://dx.doi.org/10.5755/j01.eee.111.5.373

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