BACKGROUND: There is no mature computer-aided design and manufacturing system for the preparation of removable partial denture in China so far. There is no report involving large sample size. Most of the existing studies only investigated the wear effect of a few cases, and there is a need to accumulate and enrich clinical data. OBJECTIVE: To explore the application value of intraoral scanning and 3D printing in the manufacture of removable partial dentures for patients. METHODS: Sixty-three patients with Kennedy class I dentition defect who received treatment in the Shanghai Ninth People’s Hospital, Shanghai JiaoTong University School of Medicine, China were included in this study. These patients consisted of 29 males and 34 females and were aged 44-63 years. In the study group, 23 patients were treated with denture scaffolds by intraoral scanning and three-dimensional printing, while in the control group, 40 patients were treated with denture scaffolds by traditional impression. The wear effect was compared between two groups after repair. The masticatory efficiency was compared between two groups before and 6, 12 and 24 months after repair. At the last follow-up, patients' satisfaction and complications were compared between the study and control groups. This study was approved by Shanghai Ninth People’s Hospital, Shanghai JiaoTong University School of Medicine (approval No. TJBDYY-2014-13-R1) in March, 2014. RESULTS AND CONCLUSION: The fitness (96% vs. 70%), retention (83% vs. 58%) and stability index (83% vs. 53%) of the study group were significantly higher than those of the control group (all P < 0.05). There was no significant difference in masticatory efficiency between before and 6 months after repair (P > 0.05). At 12 and 24 months after repair, the masticatory efficiency in the study group was significantly higher than that in the control group (P < 0.05). Patients' comfort satisfaction in the study group was significantly higher than that in the control group (82% vs. 50%, P < 0.05). There were no significant differences in aesthetic appearance (70% vs. 53%) and pronunciation function satisfaction (65% vs. 40%) between study and control groups. During the follow-up, there were no statistically significant differences in the incidences of periodontal disease (0 vs. 5%), denture stomatitis (4% vs. 5%) and secondary caries (9% vs. 18%) between groups (P > 0.05). These results suggest that intraoral scanning and 3D printing could obtain a more accurate stent model in the manufacture of partial dentures compared with traditional impression, thereby has a higher application value.

To study the usefulness of JPEG2000 compression for nuclear medicine (NM) image, normal and abnormal static images were compressed using a JPEG2000 plug-in. For lossless algorithm, the compressing ratio (CR) was calculated. For lossy algorithm, images were visually analyzed by NM physicians and ROC curves were generated. The area under ROC curve (AUC) was used as the index of image diagnostic quality. Paired sample t tests were performed to compare the AUCs. It was found that the lossless CR was (1.34+/-0.05) : 1. For lossy algorithm, the AUC decreased with the increase of CR. Comparison between the original and the compressed images revealed no significant difference for 10:1 CR but significant difference for bigger CRs. It was concluded that lossless compression has little usefulness for NM image because of very low CR. While lossy compression isused, the diagnostic quality of static NM images is preserved at CRs 50 : 1,40 : 1, 30 : 1,20 : 1 up to 10 : 1. For other types of NM image, CR should be increased or decreased according to their characteristics, especially the level of intrinsic statistical noise of NM image.
Algorithms ; Area Under Curve ; Artifacts ; Data Compression ; methods ; standards ; Humans ; Image Processing, Computer-Assisted ; Nuclear Medicine ; methods ; Radionuclide Imaging ; Thyroid Gland ; diagnostic imaging

Objective This study prepared gelatin three-dimensional porous microspheres and investigated the feasibility of gelatin three-dimensional porous microspheres loaded with quercetin(G-quercetin)as bone tissue scaffold material.Methods Porous gelatin microspheres were prepared by emulsification and loaded with quercetin by lyophilization.Scanning electron microscopy was used to ob-serve morphology of the microspheres.The cytotoxicity of G-quercetin microspheres and their effects on the adhesion,proliferation and differentiation of mouse embryonic osteoblast precursor cells(MC3T3-E1)were detected by immunofluorescence staining,live/dead cell staining and CCK-8 assay,alkaline phosphatase(ALP)staining and alizarin red staining.RT-PCR was used to detect the tran-scriptional levels of osteoblast-related cytokines such as Runx-2,ALP,OPN and OCN.Results The scanning electron microscopy re-sults showed that the prepared three-dimensional microporous material loaded with quercetin gelatin had a porous structure.Cell adhe-sion showed that the cells could spread well on the surface of the microspheres.Compared with the control group,the results of live/dead cell staining and CCK-8 detection showed that the microspheres had no significant cytotoxicity(P＞0.05).Compared with the con-trol group,G-quercetin microspheres showed an increase in ALP expression and mineralization in vitro.PCR results also showed a sig-nificant increase in Runx-2,ALP,OCN,OPN(P＜0.05).Conclusion The G-quercetin porous microspheres prepared in this experi-ment have good biocompatibility and can promote the osteogenic differentiation of MC3T3-E1 in vitro.It is expected to be used as a new scaffold material for bone tissue engineering.