Objective:To evaluate the effects of smokeless tobacco extract(ST) on number,morphology,ultrastructure and proliferation of human gingival fibroblasts(HGFs) on titanium in vitro.Methods:HGFs on titanium were cultured in the presence of ST at various concentrations.The cell changes in the morphology and ultrastructure were examined by scanning electrical microscope(SEM).The growth and attachment of the cells were measured by MTT method.Results:The size of the cells became smaller gradually and their shapes changed from spindle type to oval or round when the concentrations of ST increased.Ultrastructure showed that pseudopod decreased in number,the growth and attachment were dose-dependently inhibited.Conclusion:ST can change number,morphology and ultrastructure of HGFs on titanium,they can inhibit the cells growth,suggesting ST may play a pathological role on implant-gingiva interface.

Objective:To study the antimicrobial susceptibility of periodontopathic bacteria associated with failing implants to commonly used antibiotics in periodontal therapy and dental practice.Methods:Antimicrobial susceptibility of bateria isolates was determined by the method of microbroth dilution and the activities of 8 kinds of antibiotics against international laboratory strains and clinical isolates of Provotella intermedia (Pro.I), Porphyromonas gingivalis (Pg), Actinobacillus actinomycetemcomitans (Aa), Fusobacterium nucleatum (Fn) were examined.Results:Ofloxacin, clindamycin, tinidazole and metronidazole showed stronger antibacterial activity aginst Pro.I,Pg,Aa and Fn with MIC_ 90 ≤0.5 ?g/ml and MBC_ 90 ≤0.5 ?g/ml.Conclusion:Commonly-used antibiotics are potential against bacteria isolated around failing implants.

Objective Dexmedetomidine is known to have a neuroprotective effect.The aim of this study was to investigate the effects of dexmedetomidine on ketamine-induced apoptosis of primarily cultured cortical neurons and its action mechanisms. Methods Rat cortical neurons were primarily cultured for 7 days and treated with ketamine (100μmol/L) and different concentrations of dexmedetomi-dine (0.001, 0.01, 0.1, and 1 μmol/L) for 24 hours, followed by measurement of the viability of the neurons by MTT assay.The neurons were divided into four groups:vehicle control, ketamine ( trea-ted with 100 μmol/L ketamine), dexmedetomidine+ketamine (DD+K, treated with 0.1 μmol/L DD and 100 μmol/L ketamine), and LY294002 ( treated with 0.1 μmol/L DD, 100 μmol/L ketamine, and 10 μmol/L LY294002) .After 24 hours of treatment, the apoptosis rate of the neurons was determined by Hoechst33258 staining, and the expressions of pAkt and cleaved-caspase-3 in the neu-rons detected by Western blot. Results The apoptosis rate of neurons was dramatically increased in the LY294002 and ketamine groups in comparison with the vehicle control and DD+K groups ([36.8 ±4.4] and [43.4 ±4.5]%vs [7.5 ±1.1] and [16.4 ± 3.6]%, P<0.01), the pAkt level remarkably decreased (0.26 ±0.02 and 0.15 ±0.01 vs 0.61 ±0.05 and 0.50 ±0.04, P<0.01), and the expression of cleaved caspase-3 significantly upregulated in the former two as compared with the latter two groups (0.40 ±0.02 and 0.65 ±0.03 vs 0.10 ±0.02 and 0.12 ±0.01, P<0.01). Conclusion Dexmedetomidine exerts a neuroprotec-tive effect against ketamine-induced apoptosis of neurons by activating the PI3K-Akt signaling pathway.

Objective:To investigate the effects of titanium spcimens with different surface character on the proliferation and mRNA expression of IL-6 and Cbfα1 in osteoblasts.Methods:Titanium surface was treated by smooth pretreatment(PT),sandblast and acid etch(SLA)and anodic oxidation(AD)respectively.The morphology and the elements analysis of the spcimens were inspected and detected by SEMand EDS.The surface contact angle was measured by contact angle meter.MC3T3-E1 cells were cultured on the titanium surface and cells cultured on tissue culture plate were served as the control group.The proliferation was measured by MTT assay.The mRNA expression of IL-6 and Cbfα1 was quantified by RT-qPCR.Results:The sample surface in PT group showed scrat-ches,in SLA group showed multiple three dimensional structure,in AD group exhibited porous structure.The elements of the sample surface of group PT,SLA and AD were Ti,Ti/Al and Ti/O respectively;the contact angles were 54.47°±3.33°,75.42°±8.32° and 38.91 °±4.00°respectively(P<0.05).The cells in AD group showed higher proliferation than those in PT and SLA groups(P<0.05).In AD group IL-6 mRNA expression decreased and Cbfα1 mRNA increased more than in PT and SLA groups(P<0.05). Conclusion:Titanium spcimens treated with AD may promote cell proliferation,decrease IL-6 mRNA expression and increase Cbfα1 mRNA expression in MC3T3 cells.Implats treated with AD might have some advantages in early osseointegration.

BACKGROUND:Studies have confirmed that nicotine affects the activity of osteoblasts, osteoclasts, fibroblasts and erythrocytes.
OBJECTIVE:To study the nicotine effects on osseointegration and the expression of osteoprotegerin and bone morphogenetic protein 2 after implantation of dental implants with surface treatment by sandblasting or acid etching.
METHODS:Twenty-four Sprague-Dawley rats were randomly assigned to two groups and received daily injections for 2 weeks as folows: Nicotine 2 mg/kg twice for experimental group, saline solution for control group. Then the titanium implants with surface sandblasting or acid etching were implanted into the tibiae folowed by continuous nicotine or normal saline injection. At weeks 2 and 4 after implantation, the implants and surrounding bone tissue were prepared for CT, X-ray and hematoxylin-eosin staining examinations to evaluate bone healing and expression levels of bone-related genes were measured by quantitative RT-PCR.
RESULTS AND CONCLUSION: Compared with the control groups, the degree of osseointegration and the expression of osteoprotegerin and bone morphogenetic protein 2 in the experimental groups were decreased significantly (P < 0.05), except that the expression of bone morphogenetic protein 2 in the experimental group with acid etching was not significantly reduced. In addition, the expression of bone morphogenetic protein 2 in the experimental group with acid etching was higher than that in the experimental group with sandblasting at 2 weeks after implantation (P < 0.05). The X-ray and CT show that the quantities of new generation bone and the degree of bone mineralization of the sandblasting group were significant lower than those of the acid etching group under the intervention of nicotine. Hematoxylin-eosin staining showed that the activity and quantity of osteoblasts around the implants down-regulated significantly, but acid etching-treated implants showed better outcomes than sandblasting-treated implants.

Objective to probe into whether head-simulator teaching can enhance tooth cavity preparation compared with traditional preclinical teaching program.Method Questionnaires were conducted among the Grade 2002 students who had been trained by head-simulator teaching and were practicing in oral cavity section of our school.Result Majority of students think it's a good method and they have got better results than those trained in traditional experiment teaching.Conclusion The head-simulator teaching has improved the teaching quality of tooth cavity preparation but there exist some disadvantages which need further improvement and extension.

Objective To investigate the key points for management of subclinical and agonal types of penetrating cardiac trauma (PCT).Methods A retrospective analysis was conducted on clinical data of 135 PCT cases treated from January 2005 to March 2012.The cases were divided into subclinical type,clinical type (cardiac tamponade or hemorrhagic shock types) and agonal type.Managements of the two extreme types including subclinical type and agonal type were studied in groups.Results (1) Thirty cases of subclinical type failed to have timely diagnosis and treatment due to the withdrawal from inhospital observation,which resulted in 22 deaths.Eleven cases of subclinical type had timely diagnosis through in-hospital observation or cardiac exploration,but three cases died in operating room thoracotomy (ORT).There were 27 cases of agonal type,but 15 died in ORT and two died in emergency room thoracotomy (ERT).Of 67 cases of clinical type,seven died in ORT.(2) A total of 86 cases survived ORT or ERT after timely diagnosis or diagnosis through in-hospital observation plus cardiac exploration.In the meantime,sound recovery was observed in 3-24 months of follow-up.Conclusion Success rate in treatment of PCT can be enhanced by close observation and timely cardiac exploration for subclinical type PCT and by timely ERT and bleeding control for agonal type PCT.

Objective: To study the effects of UV treatment of different zirconia surfaces on the function of MC3T3-E1 osteoblasts. Methods: Disks of zirconia-based materials with smooth(S) and rough(R) surfaces were treated and with and without UV light(15 W) for 48 h,respectively. MC3T3-E1 cells were cultured on zirconia disks and divided into 4 groups: smooth group(S),UV treated smooth group(S-UV),rough group(R) and UV treated rough group(R-UV). Cell proliferation was assessed by MTT 3 and 5 days after culture. Alkaline phosphatase(ALP) activity was determined 3 and 7 days after culture. Cell mineralization was observed by Alizarin red dye staining 21 days after culture. The mRNA expression of OCN and OPG were examined by RT-PCR 7 and 14 days after culture. Results: Proliferation and mineralization of MC3T3-E1 cells in R-UV group were more than in other groups(P ＜ 0. 05). R groups showed higher ALP activity than S groups at day 7. R-UV treatment increased the mRNA expressions of OPG and OCN in a time-dependent manner(P ＜ 0. 05). Conclusion: Ultraviolet light-treated zirconia surface may promote the proliferation,mineralization and the expression of OCN and OPG of MC3T3-E1 cells.

BACKGROUND:Shikonin contributes to the promotion of bone defect repair and the treatment of osteoporosis. OBJECTIVE:To summarize the application potential of shikonin and its derivatives in oral soft and hard tissue regeneration. METHODS:A literature review was conducted in databases such as PubMed,Web of Science,Wanfang,China National Knowledge Infrastructure(CNKI),and VIP,spanning articles from 2002 to 2023.The search terms were"shikonin,oral cavity,periodontitis,antibacterial,bone formation,osteoclast,osteoporosis,toxicology"in Chinese and English. RESULTS AND CONCLUSION:Shikonin and its derivatives possess anti-inflammatory effects,inhibit periodontal pathogens such as Porphyromonas gingivalis,promote periodontal wound healing,and regenerate alveolar bone tissue.Shikonin formulations can be used to treat oral diseases such as aphthous ulcers and oral candidiasis.These findings suggest a promising future for shikonin and its derivatives in treating periodontal diseases,preventing oral ailments,and promoting the regeneration of both soft and hard periodontal tissues.Further research is needed to explore how to combine shikonin with tissue engineering to achieve quicker healing of oral soft and hard tissues.