Effects of 3 kinds of processing techniques on the fitness of metal clasp. / 3ç§åŠ å·¥å·¥è‰ºå¯¹é‡‘å±žå¡çŽ¯å¯†åˆæ€§çš„å½±å“.

OBJECTIVES: At present, removable partial denture is still one of the main restoration methods for dentition defects. However, the trend for digital partial denture is becoming more and more obvious in the field of oral repair. However, there are relatively few studies on digital removable partial denture. The aim of this study is to investigate the effects of 3 processing technologies (precision casting, digital cutting, and 3D printing) on the fitness for the clasps of cobalt chromium alloy and pure titanium removable partial denture, and to provide a theoretical basis for the clinical application of digital removable partial denture. METHODS: Clasps of Co-Cr alloy and pure titanium were produced by 3 different processing technologies (precision casting, digital cutting, and 3D printing). There are 6 groups, including a casting pure titanium group, a casting cobalt chromium group, a cutting pure titanium group, a cutting cobalt chromium group, a printing pure titanium group, and a printing cobalt chromium group (n=6 per group). The gaps between the initial, middle, and tip of the lingual opposing arm of the clasp and the abutment were measured by fluorescent microscope, and the average value was taken as the index to measure the fitness between the clasp and the abutment. The fitness difference in three-arm clasp made of cobalt chromium alloy and pure titanium materials under 3 different technologies was compared. RESULTS: There was no statistical difference in fitness between the casting pure titanium group and the casting cobalt chromium group (P>0.05); there was no statistical difference in fitness between the cutting pure titanium group and the cutting cobalt chromium group (P>0.05); there was no statistical difference in fitness between the printing pure titanium group and the printing cobalt chromium group (P>0.05). When pure titanium was used, the fitness of the printing pure titanium group was the best (both P<0.05). There was no significant difference between the casting pure titanium group and the cutting pure titanium group (P>0.05). When cobalt chromium alloy was used, there was no significant difference in fitness among the 3 groups (P>0.05). CONCLUSIONS: The cobalt chromium alloy and pure titanium clasps made by precision casting, digital cutting, and 3D printing have good fitness. Under the same process, there is no significant difference between cobalt chromium alloy and pure titanium clasps. The 3D printing pure titanium clasps have better fitness than casting pure titanium and cutting pure titanium clasps, which meet the needs of clinical application.

Anti-aging pharmacology in cutaneous wound healing: effects of metformin, resveratrol, and rapamycin by local application.

Cutaneous wounds are among the most common soft tissue injuries and are particularly hard to heal in aging. Caloric restriction (CR) is well documented to extend longevity; pharmacologically, profound rejuvenative effects of CR mimetics have been uncovered, especially metformin (MET), resveratrol (RSV), and rapamycin (RAPA). However, locally applied impacts and functional differences of these agents on wound healing remain to be established. Here, we discovered that chronic topical administration of MET and RSV, but not RAPA, accelerated wound healing with improved epidermis, hair follicles, and collagen deposition in young rodents, and MET exerted more profound effects. Furthermore, locally applied MET and RSV improved vascularization of the wound beds, which were attributed to stimulation of adenosine monophosphate-activated protein kinase (AMPK) pathway, the key mediator of wound healing. Notably, in aged skin, AMPK pathway was inhibited, correlated with impaired vasculature and reduced healing ability. As therapeutic approaches, local treatments of MET and RSV prevented age-related AMPK suppression and angiogenic inhibition in wound beds. Moreover, in aged rats, rejuvenative effects of topically applied MET and RSV on cell viability of wound beds were confirmed, of which MET showed more prominent anti-aging effects. We further verified that only MET promoted wound healing and cutaneous integrity in aged skin. These findings clarified differential effects of CR-based anti-aging pharmacology in wound healing, identified critical angiogenic and rejuvenative mechanisms through AMPK pathway in both young and aged skin, and unraveled chronic local application of MET as the optimal and promising regenerative agent in treating cutaneous wound defects.

Nestin Positive Bone Marrow Derived Cells Responded to Injury Mobilize into Peripheral Circulation and Participate in Skin Defect Healing.

Exogenously infused mesenchymal stem cells (MSCs) are thought to migrate to injury site through peripheral blood stream and participate in tissue repair. However, whether and how endogenous bone marrow MSCs mobilized to circulating and targeted to tissue injury has raised some controversy, and related studies were restricted by the difficulty of MSCs identifying in vivo. Nestin, a kind of intermediate filament protein initially identified in neuroepithelial stem cells, was recently reported as a credible criteria for MSCs in bone marrow. In this study, we used a green fluorescent protein (GFP) labeled bone marrow replacement model to trace the nestin positive bone marrow derived cells (BMDCs) of skin defected-mice. We found that after skin injured, numbers of nestin+ cells in peripheral blood and bone marrow both increased. A remarkable concentration of nestin+ BMDCs around skin wound was detected, while few of these cells could be observed in uninjured skin or other organs. This recruitment effect could not be promoted by granulocyte colony-stimulating factor (G-CSF), suggests a different mobilization mechanism from ones G-CSF takes effect on hematopoietic cells. Our results proposed nestin+ BMDCs as mobilized candidates in skin injury repair, which provide a new insight of endogenous MSCs therapy.

[Expression of RANKL/OPG in male mandible of different ages].

PURPOSE: To investigate the relationship between male osteoporosis and the expression of receptor activator of NF-κB ligand(RANKL) and osteoprotegerin(OPG)-mRNA in male mandible at different ages. METHODS: Between May 2008 and January 2009, bone tissues of the mandible were collected as the experimental material from 46 patients suffering from jaw facial deformity and extraction. The patients with periodontist, systemic disorder and smoking as well as drinking were excluded.They were divided into three groups: young group, whose age was 10-29 years old ;middle age group, whose age was 30-59 years old; aged group, whose age was 60-89 years old. The expression of RANKL mRNA and OPG mRNA was examined by real-time PCR. The data was analyzed using ANOVA followed by least significant difference (LSD) test with SPSS16.0 software package. RESULTS: (1)Compared with the young group, RANKL mRNA level in mandible was 2.1-fold and 5.3-fold higher in the middle age and aged groups, respectively, whereas OPG mRNA level was 3.3-fold and 4.8-fold higher in middle age and aged groups, respectively. RANKL and OPG were positively correlated with age.(2)The ratio of RANKL/OPG in middle age group was lower than that of young group and old group,respectively. CONCLUSIONS: (1)The expression of RANKL and OPG increases with age remarkably.(2)Bone formation of the mandible is activated in middle aged group. The formation is over absorption.(3)Bone formation of the mandible in aged group is at low level. Bone absorption exceeds bone formation.