Objective To evaluate the clinical effects of magnetic attachment on Kennedy Ⅰdentition defect.Methods Totally thirty cases of Kennedy Ⅰ dentition defect were enrolled.Magfit EX 600 magnetic attachments were applied as the extra-coronal retainer on abutment,meanwhile the guide plane and key-key way were applied as the stablizinge apparatus for dentures.The removable partial dentures with magnetic attachment were fabricated in casting framework way.After the clinical examination,X-ray and patients' subjective feeling interview,the satisfaction status to the dentures was evaluated.Results Totally thirty patients were followed up for a period ranging from 1 to 3 years.25 patients were satisfied with the dentures in both function and esthetic results.Additionally,one patient was found to have gingivitis,and 2 patients were found the attachments loosened.These 3patients were considered basically satisfied subjects.The overall satisfaction rate was 93.3％.The rest 2 patients were found alveolar bone absorption,which led to base plate of molar teeth region sinking,and partial plastic base plate of denture cracked or damaged.Therefore the 2 patients were considered as unsatisfied subjects.Conclusions The removable partial dentures with magnetic attachment not only exhibit characteristics as compact,aesthetic and comfort,but also supply reliable retention,stablization,excellent masticatory efficiency and enough protection for abutments in patients bearing Kennedy Ⅰ dentition defect.

In recent years, more and more biological materials are used in bone defect repair. The ideal materials should not only have good biocompatibility, but also have the right space structure, surface morphology and the physical and chemical properties, to adapt the growth of osteoblasts. Calcium phosphate cement was used more widely among biological materials in bone defect repair with its good biocompatibility, degradability, osteoconductivity, injection, plasticity and other advantages. This paper introduced the experimental research and progress of the calcium phosphate cement application in bone defect repair.

Objective To study the correlation between the polymorphism of GSTM1 and GSTT1 genes and the susceptibility to the development of COPD. Methods Polymerase chain reaction (PCR) was used to detect the GSTM1 and GSTT1 genotypes in 91 cases of the patients with COPD (COPD group) and 44 cases of the subjects without COPD (control group), and their susceptibility to the development of COPD were analyzed according to their gender, age and smoking history. Results There was significant difference in the frequency of GSTM1 0/0 genotype between the two groups of male persons with more than 40 years old (P

Objective To observe osteocyte survival and osteogenesis after nonvascularized free bone graft transplantation for canine mandible mass defect restoration. Methods An experimental canine premolar was extracted. 1 month later, the length of 3.0 cm edentulous mandible was cut off, as the same length as that nonvascularized and soft-free tissue complete ilium block was cut off and fixed into mandible defect in 40, 120 min. The survival osteocyte and osteogenesis of the nonvascularized graft were detected 4 and 8 weeks after transplantation. Results The continuity of canine mandible segmental defect of 3.0 cm length was repaired by free nonvascularized free bone graft, live osteocytes and osteogenesis were observed in non-vascularized free bone graft at off-body 40 min group in 4-8 weeks. But the nonvascularized free bone graft off-body 120 min was a dead bone, no survival osteocytes were observed, some osteoclasts were seen in the bone graft. Conclusion The length of 3.0 cm canine mandible defect can be restored by non-vascularized free bone graft; the osteocyte survival and osteogenesis are related to their off-body time before they are fixed into recipient.

Aim To investigate the molecular mecha-nism for the inhibitory effect of puerarin on IL-6 secre-tion in human osteoblast-likeMG-63 cells. Methods According to our previous studies, human osteoblast-like MG-63 cells containing two estrogen receptor ( ER) isoforms are a suitable model for this study. En-zyme-linked immnosorbent assay (ELISA), RT-PCR, luciferase reporter assay and small interfering RNA were performed to investigate the effect of puerarin on IL-6 expression in osteoblast-derived cells and underly-ing molecular mechanism. Results Puerarin could obviously inhibit IL-6 expression and IL-6 promoter ac-tivity by human osteoblastic MG-63 cells. Treatment with the ER antagonist ICI 182,780 abrogates the a-bove actions of puerarin on osteoblast-derived cells. U-sing siRNA technology, we further demonstrated that the effects of puerarin on IL-6 production were media-ted by ERα. Conclusion The effect of puerarin on IL-6 production in osteoblast is mediated by ERα.

Objective: To explore the impact of tennis on the visual health of primary school students, so as to provide a basis for myopia prevention. Methods: In September 2021, a total of 202 third grade students from Fengtai Affiliated School of Renmin University of China in Beijing were recruited, with 75 students in the intervention group and 127 students in the control group. In addition to attending the same cultural and physical education courses, the intervention group added a tennis course twice a week and tested their vision before the intervention (September 2021), middle (January 2022) and later (June 2022). Data collected at different time points in the two groups were analyzed by using independent sample t-test for comparison between blocks, and single factor repeated measurement ANOVA for analysis of time point factors. Results: After intervention, among male subjects, the average visual acuity of the left and right eyes in the intervention group were higher than that in the control group at the third visual acuity test (left eye:5.00±0.13,4.88±0.29, right eye:5.00±0.12,4.88±0.30, t =2.33, 2.36, P <0.05). Among female subjects, the second visual acuity test (left eye:5.03±0.17, 4.86±0.21, right eye:5.03±0.15, 4.85±0.23) and the third visual acuity test (left eye:4.97±0.13, 4.81±0.23, right eye:4.97±0.14, 4.82±0.24) showed that the average visual acuity of the left and right eyes in the intervention group were higher than that in the control group among females (second: t =3.84, 3.87, third: t =3.70, 3.46, P < 0.01 ). After intervention, the detection rate of visual impairment in both males and females control groups increased at three tests, with statistically significant differences ( χ 2=17.86, 34.77, P <0.01). In the first visual acuity test, there was no statistically significant difference in the detection rate of visual impairment between the control group and the intervention group for both males and females ( χ 2=0.01, 0.10, P >0.05). The third visual impairment detection rate of males in the intervention group was lower than that of the control group (20.00% vs 45.45%), while the second and third visual impairment detection rates of female students in the intervention group were lower than those of the control group (22.86% vs 54.00%; 28.57% vs 70.00%) ( χ 2=7.34, 8.24, 14.18, P < 0.01). Conclusions Tennis can alleviate and prevent the occurrence of myopia in primary school students to a certain extent. Sports such as tennis should be actively promoted to protect the visual health of primary school students.