Objective To summarize and analyze the clinical experiences of treatment of complicated geriatric odontoptosis for the purpose of establishing a better technique to cope with such situation.Method The data of 542 outpatients with geriatric odontoptosis,from 1998 till the present treated in the Department of Outpatient,General Hospital of PLA,were summarized and analyzed according to the type and location of odontoptosis,with complications such as severe attrition,periodontitis,food impaction and detective occlusion.The special prosthetic designs on certain cases were also summarized.Some cases were followed-up.Results Removable partial dentares(RPD)with cast framework were prescribed to the geriatric odontoptosis patients.According to the site and type of odontoptosis,four special designed frameworks include casting fence-wall enforced artificial tooth prosthesis for lower clearance cases,metal strengthened plastic occlusive pad or metal occlusive pad for severe attrition cases,casting splint prosthesis for periodontal and food impaction with impaction preventive denture.36 cases were followed up for two years with satisfactory result in 31 cases,but in four cases the clasp was broken.In the cases with failure the dentures were redesigned and fabricated with cast framework,and better results were accomplished.Generally,the patients were accustomed to the new RPD quickly and revisit times were less frequent.The strength of prosthesis was enhanced.It was proved that custom designed framework could solve the clinical dilemma of severe dentition attrition,food impaction and periodontitis,and the odontoptosis was repaired.Conclusion The designed fence-wall prosthesis,metal strengthened plastic occlusal pad and metal occlusal pad,casting splint prosthesis and casting food impaction stop are effective prosthetic procedure for certain cases.

Objective To introduce and analyze the design, manufacture and clinical effect of the casting full dentition splint in treatment of periodontal disease with or without dentition defect. Methods 148 patients with periodontal disease during 1995 to 1998 were treated with casting full dentition splint after a thorough basic periodontal treatment. The patients were composed of 81 men and 67 women aged 40-69y. The patients were followed up for 1 to 3 years after restoration. General effects of the prosthesis were evaluated based on the chief complain of patients, clinical examination and X-ray examination. Results Among 148 patients, 140 (94.59%) were satisfied with the prosthesis and stable periodontal status, 6 (4.05%) were improved, 2 (1.35%) showed no clinical effect. Conclusion Casting full dentition splint can improve the mastication efficiency in periodontal disease patients. It is an effective and reversible therapeutic method on treatment of the periodontal disease with or without dentition defect.

Objective To observe and analyze the clinical and laboratory features of the use of porcelain fused to metal(PFM) prosthesis in aged patients with loss of teeth.Methods The clinical characteristics of 63 aged patients with 138 units of PFM prosthesis were reviewed and analyzed on the fabrication and reparation processes,and all the patients were followed up for 3 months to 1 year.Results All the PFM prosthesis fit well with the abutments without loosening or drop off except 3 patients,in whom the porcelain cracked.The periodontal tissue remained healthy,and patients were satisfactory with the treatment.The requirements and key points of PFM prosthesis:(1) there must be 6-7 teeth or dental roots left in different sections of the jaw.Bone absorption around the tooth should be less than half of the root.(2) The restoration of the vertical range must be accurate.(3) Adjust the overall relations of the jaw.(4) Eliminate the early contact points to avoid crack of porcelain.(5) Choose the correct temperature and observe strictly operation protocol according to the characters of the porcelain.Conclusion Porcelain fused to metal prosthesis is a good choice in repairing the defect of dental bodies and dentition in aged patients.

Objective To evaluate the restorative effects of customarily designed resin bonded fixed partial denture(RBFPD) on single posterior tooth anodontia accompanied by tilted distal abutment,and summarize the indications and characteristics of RBFPD.Methods From 2002 to 2003,18 outpatients with single posterior tooth anodontia accompanied by tilted distal abutment were selected for the present study in the Department of Stomatology,General Hospital of People's Liberation Army.The gradient of tilted abutment was less than 50?.All the teeth with abutments were vital without obvious loosening or abnormal periodontal condition.The position and configuration of occlusion rest and retainer of denture were designed according to the inclination of abutment and cast survey.Titanium alloy or cobalt-chromium porcelain fused to metal RBFPD was prescribed,and all patients were followed up for 5 years.The clinical and X-ray examination were performed at each revisit and the subjective experience of patients was inquired.Results The average gradient of tilted distal abutment was 33?.During the period of 5-year follow-up,in all the 18 patients but 2,all the dentures were in function without detachment.The gum of abutment and the bottom of the pontic were in good condition,and no periodontitis in abutment was observed.There was no obvious change of abutment examined by X-ray during the period of follow-up.The patients were satisfactory with the prosthesis,and the success rate was 88.9% during the period of 5-year follow-up.Conclusion RBFDP used to restore the posterior single tooth anodontia with tilted abutment has the merit of less tooth reduction and reliable clinical effects,and root canal therapy is not necessary for tilted abutment.

Objective To clone and express the outer surface protein C ( OspC) from a Chinese Borrelia afzelli FP1 strain and to evaluate the immune protectivity of the recombinant OspC protein ( rOspC) . Methods The gene encoding OspC protein of Borrelia afzelli FP1 strain was amplified by polymerase chain reaction (PCR) and then inserted into pET-30a plasmid to construct the recombinant expression plasmid pET-30a-OspC. The transformed E. coli BL21 strains carrying pET-30a-OspC plasmid were induced by IPTG to express OspC protein. The expressed proteins were purified by Ni-IDA resin chromatography and analyzed by SDS-PAGE and Western blot assay. Indirect immunofluorescence assay ( IFA) was performed to detect anti-rOspC protein antibodies in serum samples from rabbits immunized with rOspC protein. In vitro neutral-ization test was performed for evaluation the immune protectivity of rOspC protein. Results The recombi-nant expression plasmid pET-30a-OspC was successfully constructed and highly expressed in E. coli BL21. A strong antigen-antibody reaction between the rOspC protein and polyclonal antibody against Borrelia afzelli FP1 strain was detected by Western blot assay. The titers of IgG in serum samples from rabbits immunized with rOspC protein were significantly elevated. The in vitro neutralization test indicated that 106/ml of Borre-lia afzelli FP1 strains were neutralized by every anti-OspC protein serum sample from the experiment group. Conclusion The rOspC protein showed a strong immune protectivity against Borrelia afzelli, which could be used in the development of polyvalent subunit vaccine against lyme disease.

Objective To predict the potential geographic distribution of Lyme disease in Qinghai by using Maximum Entropy model (MaxEnt).Methods The sero-diagnosis data of Lyme disease in 6 counties (Huzhu,Zeku,Tongde,Datong,Qilian and Xunhua) and the environmental and anthropogenic data including altitude,human footprint,normalized difference vegetation index (NDVI) and temperature in Qinghai province since 1990 were collected.By using the data of Huzhu Zeku and Tongde,the prediction of potential distribution of Lyme disease in Qinghai was conducted with MaxEnt.The prediction results were compared with the human sero-prevalence of Lyme disease in Datong,Qilian and Xunhua counties in Qinghai.Results Three hot spots of Lyme disease were predicted in Qinghai,which were all in the east forest areas.Furthermore,the NDVI showed the most important role in the model prediction,followed by human footprint.Datong,Qilian and Xunhua counties were all in eastern Qinghai.Xunhua was in hot spot area Ⅱ,Datong was close to the north of hot spot area Ⅲ,while Qilian with lowest sero-prevalence of Lyme disease was not in the hot spot areas.The data were well modeled in MaxEnt (Area Under Curve=0.980).Conclusions The actual distribution of Lyme disease in Qinghai was in consistent with the results of the model prediction.MaxEnt could be used in predicting the potential distribution patterns of Lyme disease.The distribution of vegetation and the range and intensity of human activity might be related with Lyme disease distribution.