Semaphorin3A promotes osseointegration of titanium implants in osteoporotic rabbits.

OBJECTIVE: In the present study, we intend to assess the function of Sema3A in osteointegration of titanium implants both in vivo and in vitro. MATERIAL AND METHODS: Briefly, Sema3A was transfected in HBMSCs cells to detect its effect on osteogenesis. Subsequently, an in vivo rabbit model was established. Eighteen female rabbits were randomly assigned into three groups (n=6), and rabbits in the two treatment groups (OVX groups) were subjected to bilateral ovariectomy, while those in the control group were treated with sham operation. Twelve weeks later, we first examined expression levels of Sema3A in rabbits of the three groups. Titanium implants were implanted in rabbit proximal tibia. Specifically, rabbits in sham group were implanted with Matrigel, while the remaining in the OVX experimental group (OVX+Sema3A group) and OVX group were implanted with Matrigel containing Sema3A adeno-associated virus or empty vector, respectively. RESULTS: Histomorphometry results uncovered that rabbits in the OVX+Sema3A group had a significantly higher BIC compared with those of the OVX group on the 12th week of post-implantation. And compared with the OVX group, the maximum push-out force increased by 89.4%, and the stiffness increased by 39.4%, the toughness increased by 63.8% in the OVX+Sema3A group at 12 weeks. CONCLUSION: Sema3A has a positive effect on promoting early osseointegration of titanium implants in osteoporotic rabbits. CLINICAL RELEVANCE: Our research found that Sema3A can improve the osteogenic ability of bone marrow stem cells and promotes osseointegration during osteoporosis.

[Clinical evaluation of mandibular impacted third molar removed without surgical flaps].

PURPOSE: To evaluate the effect of impacted mandibular third molars extracted without surgical flaps. METHODS: Ninety-eight patients with impacted mandibular third molars were collected. A total of 112 teeth were divided into non-surgical flap group and surgical flap group. In non-surgical flap group, the teeth were removed by transection method or T-shaped truncation method, and triangular flaps were designed in the surgical flap group. Postoperative complications at 1 day, 3 days, and 1 week after operation were recorded, and statistical analysis was performed using SPSS 17.0 software package. RESULTS: Complications such as hemorrhage, swelling, pain, mouth opening limitation and impact on daily life at postoperative 1 day and 3 day in non-surgical flap group were significantly lower than in surgical flap group (P<0.05).There was no significant difference in average operation time between the two groups (P>0.05). CONCLUSIONS: Impacted mandibular third molar can be removed without surgical flaps in selected patients. It helps alleviate patients'postoperative complications and improve their quality of life.

Poly(ethylene glycol) enhanced dehydrochlorination of poly(vinyl chloride).

Poly(ethylene glycol) (PEG), an environment-friendly reaction medium, has been adopted to accelerate the dehydrochlorination of poly(vinyl chloride) (PVC). Experimental results demonstrated that at 210 degrees C for 1h the dechlorination degree was as high as 74.2% for PVC/PEG, while for PVC only 50.0%. Moreover, from thermogravimetric analysis, it was found that for PVC/PEG the decomposition of PVC corresponding to the dehydrochlorination stage shifted to lower temperatures compared with that of pure PVC, suggesting some interactions exist between PEG and PVC that caused the faster dehydrochlorination rate. In addition, during this process, no waste byproducts such as KCl have been produced, and satisfactory recyclability of PEG (10 cycles) has been obtained.