Novel Digital Mouth Preparation Technique for Fabricating Implant-Retained Removable Partial Dentures with Distal Extension: a Case Report.

Implant-retained removable partial dentures (RPDs) are commonly used to resolve the complications associated with traditional distal extension RPDs; however, this technology does not consider the necessity and importance of parallelism between the path of RPD insertion and the long axis of the implant. This clinical report presents a novel digital preparation technique that involves the preparation of parallel guiding planes on abutment teeth and implant insertion in the distal extension area using a computer-aided design and manufacturing template. This clinical case of implant-retained RPDs illustrates the fabrication and application of the digital template. Using this technique, the path of RPD insertion is parallel to the long axis of the implant. As a result, the components of the implant-retained RPD, including the abutment teeth, implants and attachments, can demonstrate greater longevity.

High-Contrast SEM Imaging of Supported Few-Layer Graphene for Differentiating Distinct Layers and Resolving Fine Features: There is Plenty of Room at the Bottom.

For supported graphene, reliable differentiation and clear visualization of distinct graphene layers and fine features such as wrinkles are essential for revealing the structure-property relationships for graphene and graphene-based devices. Scanning electron microscopy (SEM) has been frequently used for this purpose where high-quality image contrast is critical. However, it is surprising that the effect of key imaging parameters on the image contrast has been seriously undermined by the graphene community. Here, superior image contrast of secondary electron (SE) images for few-layer graphene supported on SiC and SiO2 /Si is realized through simultaneously tuning two key parameters-acceleration voltage (Vacc ) and working distance (WD). The overlooked role of WD in characterizing graphene is highlighted and clearly demonstrated. A unified model of Vacc and WD dependence of three types of SE collected by the standard side-attached Everhart-Thornley (E-T) SE detector is conceptually developed for mechanistically understanding the improved mass thickness contrast for supported few-layer graphene. The findings reported here will have important implications for effective characterizations of atomically thick 2D materials and devices.

The use of platelet-rich fibrin combined with periodontal ligament and jaw bone mesenchymal stem cell sheets for periodontal tissue engineering.

Periodontal regeneration involves the restoration of at least three unique tissues: cementum, periodontal ligament tissue (PDL) and alveolar bone tissue. Here, we first isolated human PDL stem cells (PDLSCs) and jaw bone mesenchymal stem cells (JBMSCs). These cells were then induced to form cell sheets using an ascorbic acid-rich approach, and the cell sheet properties, including morphology, thickness and gene expression profile, were compared. Platelet-rich fibrin (PRF) derived from human venous blood was then fabricated into bioabsorbable fibrin scaffolds containing various growth factors. Finally, the in vivo potential of a cell-material construct based on PDLSC sheets, PRF scaffolds and JBMSC sheets to form periodontal tissue was assessed in a nude mouse model. In this model, PDLSC sheet/PRF/JBMSC sheet composites were placed in a simulated periodontal space comprising human treated dentin matrix (TDM) and hydroxyapatite (HA)/tricalcium phosphate (TCP) frameworks. Eight weeks after implantation, the PDLSC sheets tended to develop into PDL-like tissues, while the JBMSC sheets tended to produce predominantly bone-like tissues. In addition, the PDLSC sheet/PRF/JBMSC sheet composites generated periodontal tissue-like structures containing PDL- and bone-like tissues. Further improvements in this cell transplantation design may have the potential to provide an effective approach for future periodontal tissue regeneration.

Development and application of a rapid rehabilitation system for reconstruction of maxillofacial soft-tissue defects related to war and traumatic injuries.

BACKGROUND: The application of a maxillofacial prosthesis is an alternative to surgery in functional-aesthetic facial reconstruction. Computer aided design/computer aided manufacturing has opened up a new approach to the fabrication of maxillofacial prostheses. An intelligentized rapid simulative design and manufacturing system for prostheses was developed to facilitate the prosthesis fabrication procedure. METHODS: The rapid simulation design and rapid fabrication system for maxillofacial prostheses consists of three components: digital impression, intelligentized prosthesis design, and rapid manufacturing. The patients' maxillofacial digital impressions were taken with a structured-light 3D scanner; then, the 3D model of the prostheses and their negative molds could be designed with specific software; lastly, with resin molds fabricated by the rapid prototyping machine, the prostheses could be produced directly and quickly. RESULTS: Fifteen patients with maxillofacial defects received prosthesis rehabilitation provided by the established system. The total clinical time used for each patient was only 4 hours over 2 appointments on average. The contours of the prostheses coordinated properly with the appearance of the patients, and the uniform-thickness border sealed well to adjacent tissues. All of the patients were satisfied with their prostheses. CONCLUSIONS: The rapid simulative rehabilitation system of maxillofacial defects is approaching completion. It could provide an advanced technological solution for the Army in cases of maxillofacial defect rehabilitation.

Treatment of malignant triton tumor in zygomatic region.

Malignant triton tumor (MTT) is extremely rare and supposed to be highly aggressive because of high propensity for local recurrence and metastasis. To date, only about 170 cases were reported in various body locations including trunks, maxillary sinus, neck, extremities, retroperitoneal, and so on. We present a case of MTT in the zygoma with good outcome. A 27-year-old male patient with progressive swelling and pain in the right zygoma was proved to have an MTT by biopsy. Radical resection accompanying postoperative radiotherapy was adopted, and then the soft and hard tissue defects were repaired by prosthesis. The patient recovered well and was satisfied with the facial contour. At 45-month follow-up, there was no recurrence or metastasis that occurred. According to literature review, one third of MTTs appeared in the head and neck regions and seem to have a better prognosis. Radical resection is the most important remedy, and adjuvant radiotherapy could be helpful. With early finding and effective treatments, satisfactory outcome could be achieved.

Surgical treatment of a giant neurofibroma.

Neurofibromatosis type 1, an autosomal dominant inherited disease, presents pathologic symptoms of multiple systems, including neurofibromatosis, skeletal dysplasia, café-au-lait spots in skins, and so on. A 45-year-old man with neurofibromatosis type 1 was reported in this article. The patient presented a giant neurofibroma in his head and neck, dysplasia of skull, facial bones and spinal columns, and multiple café-au-lait spots in systematic skins. Satisfactory curative effects were obtained in this case after tumor resection and prosthesis implantation.

[Effect of pigments concentration on physical and mechanical properties of MDX-4-4210 silicone elastomer].

PURPOSE: To determine the optimum pigments concentration on the physical and mechanical properties. METHODS: In this study, control samples were prepared from MDX-4-4210 silicone base and tested along with the pigmented samples for comparison in accordance with the national standards. The pigments concentration to base elastomer was set at 0.1, 0.15, 0.2, 0.25, 0.3wt%,respectively; while other conditions were kept same, then the major physical properties of the elastomer were studied with a tensile tester. The data was processed with SPSS10.0 software package. RESULTS: When comparing the pigmented samples with the control, the tensile strength, the ultimate elongation, the tear resistance and the Shore A hardness of the MDX-4-4210 silicone elastomer was affected by the addition of the pigments. A decrease was found,while, the incorporation of pigments had no effect on the permanent deformation rate of the resulting elastomer by the addition of the pigments. CONCLUSIONS: The results obtained from physical and mechanical testing of pigmented silicone samples suggest that incorporation of 0.2wt% by weight of pigments can alter the initial physical and mechanical behavior of the base elastomer. Supported by National Natural Science Foundation of China (30630066).

Alveolar crest regeneration using curvilinear dentoalveolar distraction osteogenesis: a preliminary study.

OBJECTIVE: The objective of this study was to reconstruct alveolar crest at home position using distraction osteogenesis (DO) with a personalized curvilinear distractor designed through computer-aided technology. STUDY DESIGN: Five adult dogs were recruited and the maxillary alveolar bone from the first incisor to the first premolar was excised. The dentoalveolar segment adjacent to the defect was osteotomized as a bone transport disk. After 8 weeks of consolidation, the dogs were humanely killed, and the regenerated bone was analyzed. RESULTS: The DO was successful in the experimental group. The radiographs and histology both verified new bone bridging distraction gap. However, the newly formed bone was located more internally and was not in original position. CONCLUSIONS: The proposed method to reconstruct alveolar crest at home position is improper. The key point was how to maintain the distraction space and hold it at the home position. The barrier membrane technique may be used together with DO to resolve the problem.

[Inheritance of parthenocarpy in monoecious cucumber (Cucumis sativus L.) under different eco-environments].

By using the mixed major gene plus polygene inheritance model of quantitative traits, a joint analysis of four-generations obtained after cross between two monoecious inbred lines was made to study the inheritance of parthenocarpy in monoecious cucumber in Jiangning (Nanjing) and Changli (Hebei). The interactions between genotype and environment were detected, and the inheritance of parthenocarpy in the monoecious cucumber was fitted in E-1-1 model and controlled by two additive-dominant-epistatic major genes and additive-dominant polygene under different eco-environments. The F1 tendency and genetic parameters of the parthenocarpy were different, and the major gene heritability of F2 ranged from 42.1% to 97.5%, which was mainly due to the differences in sunlight intensity and air temperature during fruit-setting period at the two locations. It was suggested that the parents should be highly parthenocarpic in breeding program, and the characterization of parthenocarpy should be conducted under different eco-environments.

Virtual transplantation in designing a facial prosthesis for extensive maxillofacial defects that cross the facial midline using computer-assisted technology.

PURPOSE: The aim of this article was to demonstrate a novel approach to designing facial prostheses using the transplantation concept and computer-assisted technology for extensive, large, maxillofacial defects that cross the facial midline. MATERIALS AND METHODS: The three-dimensional (3D) facial surface images of a patient and his relative were reconstructed using data obtained through optical scanning. Based on these images, the corresponding portion of the relative's face was transplanted to the patient's where the defect was located, which could not be rehabilitated using mirror projection, to design the virtual facial prosthesis without the eye. A 3D model of an artificial eye that mimicked the patient's remaining one was developed, transplanted, and fit onto the virtual prosthesis. A personalized retention structure for the artificial eye was designed on the virtual facial prosthesis. The wax prosthesis was manufactured through rapid prototyping, and the definitive silicone prosthesis was completed. RESULTS: The size, shape, and cosmetic appearance of the prosthesis were satisfactory and matched the defect area well. The patient's facial appearance was recovered perfectly with the prosthesis, as determined through clinical evaluation. CONCLUSION: The optical 3D imaging and computer-aided design/computer-assisted manufacturing system used in this study can design and fabricate facial prostheses more precisely than conventional manual sculpturing techniques. The discomfort generally associated with such conventional methods was decreased greatly. The virtual transplantation used to design the facial prosthesis for the maxillofacial defect, which crossed the facial midline, and the development of the retention structure for the eye were both feasible.