The intraoral scanning of the edentulous arch might be challenging for an inexperienced operator because of the large mucosal area and the use of scan bodies. The purpose of this ex vivo study was to compare the trueness of 5 intraoral scanners in replicating implant scan bodies and soft tissues in an edentulous maxilla and to investigate the effects of operator experience. The maxilla was resected from a fresh cadaver, 5 implants placed, and a reference scan made. Eight scans were made by experienced operators and 8 by an inexperienced operator with each scanner (iTero Element 2, Medit i500, Primescan, TRIOS 3, TRIOS 4). The implant platform deviation was measured after complete surface alignment and after scan body alignment. Deviation data were analyzed with a generalized linear mixed model (α=.05). After complete surface alignment, the mean ±standard deviation implant platform deviation was higher for the inexperienced operator (421 ±25 μm) than for experienced ones (191 ±12 μm, P<.001) for all scanners. After scan body alignment, no significant differences were found between operators for Element 2, Primescan, and TRIOS 3. The experienced operators produced a lower deviation for TRIOS 4 (35 ±3.3 μm versus 54 ±3.1 μm, P<.001), but higher deviation for i500 (68 ±4.1 μm versus 57 ±3.6 μm, P<.05). The scanner ranking was Element 2 (63 ±4.1 μm), i500 (57 ±3.6 μm, P=.443), TRIOS 4 (54 ±3.1 μm, P=.591), TRIOS 3 (40 ±3.1 μm, P<.01), Primescan (27 ±1.6 μm, P<.001) for the inexperienced operator and i500 (68 ±4.1 μm), Element 2 (58 ±4.0 μm, P=.141), TRIOS 3 (41 ±2.8 μm, P<.001), TRIOS 4 (35 ±3.3 μm, P=.205), Primescan (28 ±1.8 μm, P=.141) for the experienced operators. Mucosal alignment greatly overestimated the platform deviation. The intraoral scanners showed different trueness during the complete-arch implant scanning. The operator experience improved the trueness of the edentulous mucosa but not implant platform deviation.

The study aimed to compare the precision of ATOS industrial, 3ShapeE4, MeditT710, CeramillMap400, CSNeo, PlanScanLab desktop, and Mediti700 intraoral scanners. The second aim was to compare the trueness of Mediti700 assessed by ATOS and desktop scanners. Four plastic dentate models with 7-12 abutments prepared for complete arch fixed dentures were scanned by all scanners three times. Scans were segmented to retain only the abutments. The precision and trueness were calculated by superimposing scans with the best-fit algorithm. The mean absolute distance was calculated between the scan surfaces. The precision was calculated based on the 12 repeats. Trueness was evaluated by superimposing the desktop and IOS scans to the industrial scans. IOS was also aligned with the two most accurate desktop scanners. The precision of 3ShapeE4 and MeditT710 (3-4μm) was only slightly lower than that of ATOS (1.7μm, p<0.001) and significantly higher than CeramillMap400, CSNeo, and PlanScanLab (6-10 μm, p<0.001). The trueness was the highest for the 3Shape E4 (12-13 μm) and Medit T710 (13-16 μm) without significant difference. They were significantly better than CeramillMap400, CSNeo, and PlanScanLab (22-31μm, p<0.001). Accordingly, the Mediti700 trueness was evaluated by ATOS, 3ShapeE4, and MeditT710. The three trueness was not significantly different; ATOS (23-26 μm), 3Shape E4 (22-25 μm), and Medit T710 (20-23 μm). All desktop scanners had the acceptable accuracy required for a complete arch-fixed prosthesis. The 3Shape E4 and the Medit T710 might be used as reference scanners for studying IOS accuracy. 3ShapeE4, MeditT710, CeramillMap400, CSNeo, PlanScanLab laboratory, and Mediti700 intraoral scanners can be used for the prosthetic workflow in a complete arch. 3ShapeE4 and the MeditT710 could be used to test the accuracy of various phases of a laboratory workflow, replacing the industrial scanners.

Backgrounds: Intraoral scanner (IOS) accuracy is commonly evaluated using full-arch surface comparison, which fails to take into consideration the starting position of the scanning (scan origin). Previously a novel method was developed, which takes into account the scan origin and calculates the deviation of predefined identical points between references and test models. This method may reveal the error caused by stitching individual images during intraoral scan. This study aimed to validate the novel method by comparing the trueness of seven IOSs (Element 1, Element 2, Emerald, Omnicam, Planscan, Trios 3, CS 3600) to a physical impression digitized by laboratory scanner which lacks linear stitching problems. Methods: Digital test models of a dentate human cadaver maxilla were made by IOSs and by laboratory scanner after polyvinylsiloxane impression. All scans started on the occlusal surface of the tooth #15 (universal notation, scan origin) and finished at tooth #2. The reference model and test models were superimposed at the scan origin in GOM Inspect software. Deviations were measured between identical points on three different axes, and the complex 3D deviation was calculated. The effect of scanners, tooth, and axis was statistically analyzed by the generalized linear mixed model. Results: The deviation gradually increased as the distance from scan origin increased for the IOSs but not for the physical impression. The highest deviation occurred mostly at the apico-coronal axis for the IOSs. The mean deviation of the physical impression (53 ± 2 μm) was not significantly different from the Trios 3 (156 ± 8 μm) and CS 3600 (365 ± 29 μm), but it was significantly lower than the values of Element 1 (531 ± 26 μm), Element 2 (246 ± 11 μm), Emerald (317 ± 13 μm), Omnicam (174 ± 11 μm), Planscan (903 ± 49 μm). Conclusions: The physical impression was superior compared to the IOSs on dentate full-arch of human cadaver. The novel method could reveal the stitching error of IOSs, which may partly be caused by the difficulties in depth measurement.

The laser speckle contrast imaging (LSCI) is proved to be a reliable tool in flap monitoring in general surgery; however, it has not been evaluated in oral surgery yet. We applied the LSCI to compare the effect of a xenogeneic collagen matrix (Geistlich Mucograft®) to connective tissue grafts (CTG) on the microcirculation of the modified coronally advanced tunnel technique (MCAT) for gingival recession coverage. Gingival microcirculation and wound fluid were measured before and after surgery for six months at twenty-seven treated teeth. In males, the flap microcirculation was restored within 3 days for both grafts followed by a hyperemic response. During the first 8 days the blood flow was higher at xenogeneic graft comparing to the CTG. In females, the ischemic period lasted for 7–12 days depending on the graft and no hyperemic response was observed. Females had more intense and prolonged wound fluid production. The LSCI method is suitable to capture the microcirculatory effect of the surgical intervention in human oral mucosa. The application of xenogeneic collagen matrices as a CTG substitute does not seem to restrain the recovery of graft bed circulation. Gender may have an effect on postoperative circulation and inflammation.

There is no effective treatment for the loss of functional salivary tissue after irradiation for head and neck cancer or the autoimmune disease Sjögren's syndrome. One possible approach is the regeneration of salivary glands from stem cells. The present study aimed to investigate whether small pieces of human submandiblar gland tissue contain elements necessary for the reconstruction of salivary rudiments in vitro via acinar and ductal cell differentiation. Primary submandibular gland (primary total human salivary gland; PTHSG) cells were isolated from human tissue and cultured in vitro using a new method in which single cells form an expanding epithelial monolayer on plastic substrates. Differentiation, morphology, number, and organization of these cells were then followed on basement membrane extract (BME) using RNA quantitation (amylase, claudin-1 (CLN1), CLN3, kallikrein, vimentin), immunohistochemistry (amylase and occludin), viability assay, and videomicroscopy. On the surface of BME, PTHSG cells formed acinotubular structures within 24 h, did not proliferate, and stained for amylase. In cultures derived from half of the donors, the acinar markers amylase and CLN3 were upregulated. The PTHSG culture model suggests that human salivary gland may be capable of regeneration via reorganization and differentiation and that basement membrane components play a crucial role in the morphological and functional differentiation of salivary cells.