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@#The ultimate treatment goal of periodontitis is the structural and functional regeneration of periodontium. However, existing methods for periodontal regeneration have difficulties in regenerating the hierarchical structure. Therefore, stem cell-based tissue engineering has attracted more and more attention for its advantages of self-renewal and multi-lineage differentiation potential. This review summarized the progress of research on periodontal tissue regeneration by combined biomaterials of dental-derived stem cells. It is pointed out that the application of autologous stem cell transplantation is limited by the donor source, and the subsequent research should focus on the development of multi-phase scaffold materials and the attempt to establish a stem cell bank.
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Objective To analyze the influence of different materials on thermal stress field of the bipolar high-frequency electric knife. Methods The electric-thermal coupling simulation analysis was performed for thermal stress field in working process of the bipolar high-frequency electric knife. The influence patterns for 4 kinds of insulating layer materials 304 stainless steel, 316 stainless steel, 317 stainless steel, Ti6Al4V and 4 kinds of electrode materials polypropylene (PP), polyamide-6 (PA6), polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) on thermal stress field and thermal deformation field of insulating layer, electrode and coating of bipolar high-frequency electric knife and myocardial tissues were studied. Results The thermal deformation of myocardial tissues was much higher than that of the components of high-frequency electric knife in period of 2 s for continuous power. In terms of myocardial tissue protection, 304 stainless steel was the best electrode material for high-frequency electric knife. For choosing PP as the insulating layer material, thermal deformation of myocardial tissues caused by thermal stress was the smallest, which could better maintain the integrity of myocardial tissues. Conclusions The manufacturing materials of high-frequency electric knife have an important influence on thermal stress field in its working process. The regularity analysis results can provide guidance for the development of high-frequency electric knife.
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Research have indicated that inadequate keratinized tissue has a negative effect on patient oral hygiene, resulting in peri-implant inflammation. It has been recommended that an apically repositioned flap alone or in combination with autogenous soft tissue grafts can increase the width of keratinized mucosa around dental implants, which promotes long term peri-implant health. This review summarized research progress on augmentation techniques of keratinized tissue arround implants in recent years, so as to provide reference for clinical practice and research design in the future.
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Objective To analyze the influence regularities of different sizes on thermal stress field of bipolar high-frequency electric knife. Methods Based on the ANSYS software, the electric-thermal coupling simulation analysis was performed for thermal stress field of bipolar high-frequency electric knife during working. The effects of 3 different insulation layer thicknesses (0-5, 1-0, 1-5 mm), electrode thicknesses (0-5, 1-0, 1-5 mm) and coating thicknesses (3, 6, 9 μm) on thermal stress field of bipolar high-frequency electric knife were studied. Results If thickness of the insulation layer was larger, deformation of the myocardial tissues would be smaller due to thermal stress, that is, the thickness of the insulation layer was inversely proportional to thermal deformation of the myocardial tissue during working process of the high-frequency electric knife. For the 3 electrode thicknesses, 1-0 mm was a better choice. And for the 3 coating thicknesses, 6 μm was a better choice. Conclusions The component sizes for the high-frequency electric knife have an important influence on thermal stress field, and the result can provide guidance for design of the high-frequency electric knife.
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Objective The ammonia level in air and heavy metals in drinking water were explored in a cynomolgus monkey feedlot. Methods Air ammonia from different communities and feeding patterns of cynomolgus monkeys were collected at three time-points per day and determined by Nessler's reagent spectrophotometry. Inductively coupled plasma mass spectrometry was applied to detect the level of heavy metals in drinking water from 5 different sampling sites in the feedlot,incluing the outlet of underground water,the water tank,both monkey cages equipped with PVC or iron pipes and sewage lagoon,respectively. Results Air ammonia levels in quarantine inspection flock cages(0.59 ± 0.03 mg/m3)were significantly higher than in the cages of both reproductive flock(0.34 ± 0.03 mg/m3)and sale flock(0.27 ± 0.04 mg/m3). The ammonia level in air in different feeding patterns ranks as following:cage rearing of quarantine inspection flock(0.59 ± 0.03 mg/m3)>cage rearing of reproductive flock(0.48 ± 0.02 mg/m3)>captive bleeding of sale flock(0.30 ± 0.02 mg/m3)>cage rearing of sale flock(0.25 ± 0.01 mg/m3)> captive bleeding of reproductive flock(0.22 ± 0.02 mg/m3). The air ammonia concentrations of both former flocks were statistically higher than the latter three flocks. The highest air ammonia level among different flocks and feeding patterns occurred in the morning, before waste discharge clean-up. The iron concentration in drinking water in the cages equipped with iron pipes was higher than Chinese drinking water standard. Conclusions The air ammonia level was lower than the Chinese air quality standard. The iron concentration in drinking water in the cages equipped with iron pipes was higher than the Chinese drinking water standard.
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Objective To study the application value of endoscopic purse-string sutures with titanium clips and endoloops for the gastric wall defect during endoscopic full-thickness resection (EFTR). Methods Data of iffteen hospitalized patients with gastric submucosal tumor (SMT) undergone EFTR was reviewed. The patients were all applied with endoscopic purse-string sutures with titanium clips and endoloops, which was performed after the EFTR when the gastric walls were perforated artiifcially. Results The gastric tumors were complete successfully resected in the iffteen patients through endoscopic surgery, applied the purse-string sutures with titanium clips and endoloops after the EFTR when the gastric walls were perforated artiifcially. Approximately, ifve clips were utilized on average. Postoperative surgical wound healing was followed up for 6 months, no tumors recurred. Conclusion It is safe, minimally invasive treatment method for rapid rehabilitation in endoscopic full-thickness resection utilized purse-string sutures with titanium clips and endoloops.