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Metal−semiconductor−metal (MSM) photodetectors (PDs) are used for optoelectronic integrated circuits (OEICs) because they allow easy integration with a preexisting circuit. However, traditional MSM PDs require an external bias to separate the electron−hole pairs because they have a symmetrical structure. This study proposes a method to create an asymmetric Schottky barrier height in a MSM PD with a symmetrical interdigital electrode. A localized surface fluorine plasma treatment is applied to a specific area of the a-IGZO film underneath the contacts of the MSM PDs, which produces a localized oxygen deficiency. The photocurrent spontaneously diffuses because there is an asymmetric Schottky barrier. This gives the device self-powering characteristics. The a-IGZO MSM PD with a symmetrical interdigitate electrode operates at a zero bias and has a responsivity of 5 mA/W. The open-circuit voltage under illumination at 365 nm (2 mW/cm 2 ) is 0.20 V. This study demonstrates that this method is applicable to other MSM PDs, particularly those that use an amorphous oxide semiconductor as the active layer.

With the rapid development of computer‐aided design/computer‐aided manufacturing (CAD/CAM) systems, the application of zirconia in removable partial dentures is expected to expand. Clasps composed of zirconia should improve esthetics without inducing the risk of metal allergy. The aim of this study was to examine the fatigue resistance of yttria‐stabilized tetragonal zirconia polycrystal (Y‐TZP) clasps for removable partial dentures. Yttria‐stabilized tetragonal zirconia polycrystal and cobalt‐chromium (Co‐Cr) alloy were prepared using CAD/CAM systems. Specimens were either of the semicircular type or of the flat type, with cross‐sectional areas of taper ratios of 0.50, 0.75, and 1.00. All specimens were tested using the cantilever test and the constant displacement fatigue test, and data were analyzed using ANOVA. During the cantilever test, the maximum displacement prior to fracture was greater than the required undercut, and the semicircular‐type specimen exhibited a higher fracture load than the flat type. None of the specimens displayed permanent deformation and showed almost the same degree of deformation after fatigue testing. A lower taper ratio was associated with lower average load values and greater displacement. Within the limitations of this study, it was possible to conclude that Y‐TZP provides the required undercut and adequate retentive force for removable partial denture clasps. Additionally, Y‐TZP and Co‐Cr alloy had almost the same degree of deformation even after the simulated lifespan of removable partial dentures.

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Poly-ether-ether-ketone (PEEK) is an aesthetically pleasing natural material with good biocompatibility and shock absorption characteristics. The application of PEEK as a dental implant or abutment is expected to reduce the risk of failure and enhance aesthetics. Given that approximately one in 15 patients have allergic reactions to antibiotics, photodynamic therapy (PDT) has been gaining attention as an alternative treatment. Herein, the applicability of PEEK dental implants or abutments was investigated using material analyses, biofilm formation assay, and cell viability tests. The possible use of PDT for peri-implant mucositis was evaluated with the biofilm removal assay. The obtained data were analyzed based on the multivariate analysis of variance, paired t-tests, and the Pearson correlation coefficient (α = 0.05). The results revealed that PEEK was significantly less conducive to the formation of biofilms with S. mutans and A. actinomycetemcomitan (p < 0.001) but exhibited comparable MG-63 (human osteoblast-like) osteoblast cell viability (p > 0.05) to the other materials. PDT had similar antimicrobial efficacy and yielded similar biofilm removal effects to antibiotics. Altogether, these findings suggest that PEEK has attractive features and can serve as an alternative material for dental implants or abutments. In cases where peri-implant mucositis occurs, PDT can be used as an accessible therapeutic approach.

Background: Supernumerary teeth are a common anomaly and are frequently observed in paediatric patients. To prevent or minimize complications, early diagnosis and treatment is ideal in children with supernumerary teeth. Aim: This study aimed to apply convolutional neural network (CNN)-based deep learning to detect the presence of supernumerary teeth in children during the early mixed dentition stage. Design: Three CNN models, AlexNet, VGG16-TL, and InceptionV3-TL, were employed in this study. A total of 220 panoramic radiographs (from children aged 6 years 0 months to 9 years 6 months) including supernumerary teeth (cases, n = 120) or no anomalies (controls, n = 100) were retrospectively analyzed. The CNN performances were assessed according to accuracy, sensitivity, specificity, receiver operating characteristic (ROC) curves, and area under the ROC curves for a cross-validation test dataset. Results:The VGG16-TL model had the highest performance according to accuracy, sensitivity, specificity, and area under the ROC curve, but the other models had similar performance. Conclusion:CNN-based deep learning is a promising approach for detecting the presence of supernumerary teeth during the early mixed dentition stage.

The purpose of this research is to compare the cytotoxicity of polyetheretherketone (PEEK) and polyetherketoneketone (PEKK) with conventional dental implant–abutment materials, namely titanium alloy (Ti-6Al-4V) and yttria-stabilized tetragonal zirconia polycrystal (Y-TZP), to evaluate the cell metabolic activity, cytotoxicity, and inflammation potential of human oral fibroblasts (HOF) on these materials. Disk-shaped specimens were designed and prepared via a dental computer-aided manufacturing technology system. Surface topography, roughness, and free energy were investigated by atomic force microscope and contact angle analyzer; cell metabolic activity and cytotoxicity by MTT assay; and morphological changes by scanning electron microscopy (SEM). The effect of pro-inflammatory gene expression was evaluated by RT-qPCR. The obtained data were analyzed with one-way analysis of variance and post-hoc Tukey’s honest significant difference tests. PEEK and PEKK exhibited higher submicron surface roughness (0.04 μm) and hydrophobicity (>80°) than the control. Although the cell activity of PEEK was lower than that of Ti-6Al-4V and Y-TZP for the first 24 h (p < 0.05), after 48 h there was no difference (p > 0.05). According to the cell cytotoxicity and the pro-inflammatory cytokine gene expression assays, there was no difference between the materials (p > 0.05). SEM observations indicated that HOF adhered poorly to PEKK but properly to Ti-6Al-4V, Y-TZP, and PEEK. PEEK and PEKK show comparable epithelial biological responses to Ti-6Al-4V and Y-TZP as implant–abutment materials. Between the two polymeric materials, the PEEK surface, where the HOF showed better cell metabolic activity and cytotoxicity, was a more promising implant–abutment material.