Osaka Dental University (大阪歯科大学, Ōsaka shika daigaku) is a private university in Hirakata, Osaka, Japan. The predecessor of the school was founded in 1911, and it was chartered as a university in 1947. There is a hospital associated with the university located near Temmabashi Station in Chūō-ku, Osaka..
This study aimed to evaluate the clinical feasibility of dental magnetic resonance imaging (MRI) using a microscopy coil by comparing imaging positions in healthy volunteers. Twenty-six healthy volunteers underwent dental MRI in supine and prone positions using a 47 mm microscopy coil on a 3.0T system. T1-weighted (T1W), T2-weighted (T2W), and proton density-weighted (PDW) sequences were acquired. Participant-reported burden was assessed using a 10-point scale. Image quality was evaluated using a 4-point scale for sharpness, artifact, perceived signal-to-noise ratio (SNR), and overall quality. SNR and contrast-to-noise ratio (CNR) were calculated from 1 mm2 regions of interest in dental pulp, inferior alveolar neurovascular bundle, and bone marrow. Statistical analyses included the Wilcoxon signed-rank test, Fisher’s exact test, and paired t-test. Participant-reported burden was lower in the supine position (1.7 ± 1.1) than in the prone (4.7 ± 2.1). Visual assessments demonstrated superior image quality in supine across all sequences. The proportion of non-diagnostic images was higher in the prone position: T1W (50
Background: Autogenous tooth-derived grafts have been proposed as an alternative to xenografts for alveolar ridge preservation, offering biological similarity to bone and potentially more favorable remodeling. This study compared the healing outcomes of a collagenated xenograft, and a tooth-derived graft prepared with an automated processing device. Methods: Six Beagle dogs underwent bilateral extraction of the third and fourth mandibular premolars. Each animal contributed two sockets grafted with root-derived particulate prepared using an automated device for tooth cleaning, grinding, and demineralization, and two sockets grafted with a collagenated xenograft, all covered by a collagen membrane. After 3 months, histological sections were analyzed to assess crestal dimensions and the relative proportions of mature (lamellar) and immature bone (woven/parallel fibered), residual graft material, and soft tissues. Results: Lingual crest height did not differ between groups, whereas the buccal crest was slightly higher at xenograft sites compared with the tooth-graft sites. The tooth-graft group exhibited significantly fewer residual particles (0.5 ± 1.1%) and a higher proportion of total bone (65.6 ± 9.1%) compared with the xenograft group, which showed 19.7 ± 16.0% graft remnants (p = 0.032). Corticalization at the socket entrance was observed predominantly in the tooth-graft sites. No inflammatory infiltrates were detected in the examined section. Conclusions: Tooth-derived grafts promoted an almost complete replacement by vital bone with minimal residual material, whereas xenografts provided slightly better buccal contour preservation but resulted in regenerated tissues containing persistent graft particles. The biological differences observed may have implications for subsequent implant placement.
Mastication is a physiological process that facilitates swallowing, digestion, and flavor perception. The timing from chewing to the swallowing threshold may be influenced by flavor perception, including retronasal aroma reaching the nasal cavity during chewing, as well as by oral and pharyngeal function. We aimed to examine the effects of oral function and retronasal aroma on the swallowing threshold by modifying the aroma content of standardized gummy jellies. Thirty adults (15 women, 15 men; age 26.4 +/- 3.4 years) participated in this study. The test food was a gummy jelly standardized for masticatory performance assessment, with four levels of aroma content. Masticatory performance was measured using gummy jellies with image analysis, and the stimulated saliva flow rate was measured using flavorless paraffin wax. Retronasal aroma intensity was measured using a portable odor sensor positioned at the nostrils under conditions close to natural eating. Participants ingested aroma-adjusted gummy jellies three times, in random order, and we measured the retronasal aroma intensity, number of chewing strokes, and chewing duration until reaching the swallowing threshold. Flavor perception during chewing was evaluated using a visual analog scale. The results showed that retronasal aroma intensity increased with higher gummy jelly aroma content. Furthermore, chewing strokes until reaching the swallowing threshold increased with higher aroma content, even after adjusting for masticatory performance and salivary flow rate. No significant differences were observed in visual analog scale scores. These findings suggest that enhanced retronasal aroma may contribute to prolonging mastication before swallowing under near-natural eating conditions.
PURPOSE:This study compared the mechanical properties, wear behavior, and shear bond strength (SBS) of resin luting agents in additive-manufactured composite crown materials intended for definitive restorations with those of conventional computer-aided design/computer-aided manufacturing (CAD-CAM) hybrid composite resin (HCR) block materials. METHODS:Sprintray Ceramic Crown (SP) was used as the representative vat photopolymerization (VPP)-fabricated material based on additive manufacturing, whereas Shofu Block HC Hard II (HC) and Cerasmart Prime (CS) were selected as CAD-CAM HCR block materials. The mechanical properties were evaluated using three-point flexural strength and Vickers hardness tests. The wear behavior was examined via a reciprocating sliding test using an alumina ball antagonist. The SBS was measured between each material and various resin-luting agents. RESULTS:SP showed ~50-60% of the flexural strength and 30-40% of the Vickers hardness of HC and CS. Wear testing revealed that SP exhibited greater wear loss than those of CAD-CAM HCRs. The SBS values of SP with each resin cement were slightly lower than those of HC and CS under most conditions; however, all values exceeded 15 MPa, indicating a clinically acceptable bond strength. CONCLUSIONS:The VPP-fabricated definitive crown material (SP) demonstrated inferior mechanical properties and wear resistance compared to those of conventional CAD-CAM HCRs. However, the acceptable levels of bond strength were observed, highlighting the importance of careful case selection for definitive restorations.
Structures of nucleoprotein (N)-RNA complexes of the Bornaviridae, a virus family in the order Mononegavirales, have not been reported. Here, using cryo-electron microscopy (cryo-EM), we report high-resolution structures of Borna disease virus 1 (BoDV-1) N-RNA complex assemblies, including a dominant hexameric ring-like complex and less populated heptameric and octameric forms, the first RNA-bound N structures reported from this family. These structures reveal key features of N-RNA engagement and a BoDV-1-specific stoichiometry of eight nucleotides per N, providing a framework for comparison with related negative-strand RNA viruses. In addition to these RNA-bound complexes, we identified multiple RNA-free oligomers, indicating substantial conformational flexibility of N. Mutational analyses identified residues essential for nucleocapsid formation and RNA synthesis. Cryo-EM of mutant complexes captured RNA-free assemblies, suggesting that initial N oligomerization precedes RNA binding. These findings clarify the structural organization of the N-RNA complex and suggest how oligomeric plasticity contributes to nucleocapsid assembly.
