[Effect of polishing method and time on the fitness of CAD/CAM zirconia ceramic crown].

PURPOSE: To compare the effect of different polishing methods and time treatment on the fitness of CAD/CAM zirconia ceramic crowns. METHODS: Sixteen intact maxillary premolars were randomly divided into two groups, group A was treated with silicon carbide burs, while group B was treated with tungsten steel burs. At different polishing time points of the same tooth, digital impressions of each group were obtained, which were used to manufacture CAD/CAM zirconium ceramic crowns. After trial fitting, the gap impressions were obtained by using silicone rubber replication method, and the marginal and internal discrepancies were assessed. The data were statistically analyzed with SPSS 21.0 software package. RESULTS: The difference between the gap values of the marginal and internal markers of group A and group B was not statistically significant(P＞0.05). Compared with the no-polishing process, the differences of the marginal gap (39.67±8.35) µm and internal gap (45.18±7.16) µm of group A polished for 4 min, and the marginal gap (51.25±14.73) µm, and internal gap (48.56±6.45) µm of group B polished for 3 min, as well as the marginal gap (48.87±8.90) µm, and internal gap (45.99±7.12) µm of group B polished for 4 min, were all significant(P＜0.05). CONCLUSIONS: CAD/CAM zirconia ceramic crowns treated with silicon carbide bur for polishing 4 min and tungsten steel for 3 min has the best fitness.

[Effect of chronic sleep deprivation on condylar cartilage in rats].

PURPOSE: The aim of this study was to investigate the morphological changes of condylar cartilage of temporomandibular joint (TMJ) and the expression changes of IL-1ß,TNF-α,IGF-1 and VEGF in condylar cartilage of TMJ by establishing a chronic sleep deprivation model in rats. METHODS: Sixty rats were randomly divided into experimental group, control group and recovery group. Modified multiple platforms method (MMPM) was used to build chronic sleep deprivation models in experimental and recovery groups. Rats in the recovery group received 1 week of cage feeding after sleep deprivation. H-E staining was used to observe morphological change of the condyle. Immunohistochemical method was performed to detect the changes of IL-1ß, TNF-α, IGF-1 and VEGF. The data was processed by using SPSS 23.0 software package. RESULTS: MMPM can establish chronic sleep deprivation model effectively. H-E staining showed condylar cartilage of the experimental group was split stripped, and the boundaries of cartilage cell layer became blurred. Compared with the control group, the recovery group had less cracks in the fibrous layer or some of the cracks were occupied by fibrous tissue. Immunohistochemistry showed that the positive expression intensity of IL-1ß and TNF-α in the experimental group was significantly higher than in the control group (P＜0.05), the positive expression intensity in the recovery group was significantly lower than in the experimental group(P＜0.05). The positive expression intensity of IGF-1 and VEGF in the experimental group was significantly higher than in the control group(P＜0.05). The expression of IGF-1 and VEGF decreased significantly in the recovery group which received sleep deprivation no more than 3 weeks(P＜0.05). CONCLUSIONS: Chronic sleep deprivation can increase the expression of IL-1ß, TNF-α and VEGF in condylar cartilage and aggravate osteoarthritis. Chronic sleep deprivation can lead to increase of IGF-1 in condylar cartilage tissue, which plays a crucial role in protecting and promoting the reconstruction of condylar cartilage. After chronic sleep deprivation, the expressions of IL-1ß, TNF-α, IGF-1 and VEGF in the condylar cartilage of rats were decreased after 1 week of recovery, and the condylar cartilage underwent restorative reconstruction.

EQUITY AND SATISFACTION OF COMMUNITY HEALTH SERVICES IN TONGLIAO CITY, INNER MONGOLIA.

We aimed to describe the human resources and apparatuses of community health service (CHS) in Tongliao City of China and investigate the differences between CHS centers and stations. Field investigations and questionnaire-based surveys were conducted in 120 CHS organizations of Tongliao City, which were selected by a stratified multistage random cluster sampling method. Data were collected on the human resources, medical apparatuses, and satisfaction of covered residents. We found that the total number, educational background, and professional titles of staff were lower at stations than at centers. Although the categories of providing health services were comparable between centers and stations, stations provided fewer health services than centers did. In addition, stations owned fewer apparatuses compared with centers. The percentages of satisfaction on many items were lower among residents covered by stations than among those covered by centers. Desired health services provided by CHS organizations have been partially accomplished in Tongliao City. Attracting more highly educated professionals and purchasing more valuable apparatuses may be helpful to improve the unbalanced distribution in human resources and apparatuses between centers and stations. Appropriate modifications of corresponding policies should be taken into consideration by the local government in the future.