37 free second molar residual crowns were repaired by glass fiber post and resin core(GF group),and another 37 by cobalt chromium alloy casting post and core(CCA group).The success rate of 1 ~5 years of GF group was 1 00%,1 00%,91 .9%,86.5% and 81 .1 %;that of CCA group 97.3%,91 .9%,83.8%,81 .1 % and 73.0%,respectively(P >0.05).

Objective: To investigate the osteointegration and osteoinduction of nano hydroxyapatite/bioglass ( nHA/BG ) gradient nanofilm on the surface of titanium ( Ti) prepared by hypotherm sintering and plastic deformation. Methods:Hypotherm sintering was used to produce nHA/BG gradient coating followed by soaking in the simulated body fluid. Ti implants with gradient coatings were planted in femoral condyles at one side of 12 New Zealand rabbits and the untreated Ti implants were planted at the other side as the controls. 1, 3 and 6 months after implantation, the animals were sacrificed after X-ray examination and the tissues around the implants from the 3 month group were used for the preparation of hard tissue section and ground section. New bone formation was observed by tetracycline fluorescence staining. Von Gieson staining was used to observe the osteointegration at the interface between bone and im-plant. Results:The gradient coatings were porous and composed of irregular rod-like nano-HA crystals. Animal study showed well es-tablished osteointegration between the gradient coating and more novel bone was found around the implants with gradient coatings. Conclusion:Osteointegration and ostioinduction of Ti implant can be enhanced by nanostructured surface with gradient coatings of nHA/BG.

BACKGROUND:The peri-implant bone absorption is closely related to the repair effect. OBJECTIVE:To compare the effects of three kinds of dental implant systems on the peri-implant bone absorption. METHODS:116 patients who underwent the dental implant systems were col ected, including 46 cases with 3I implant system, 40 cases with ITI implant system and 30 cases with BLB implant system. The peri-implant bone absorption, sulcus bleeding index and periodontal probing depth of three groups were detected at 1, 3, 6, 9 and 12 months after implantation, respectively. RESULTS AND CONCLUSION:The peri-implant bone absorption of three groups within 1 year after implantation was in a rise, and the bone absorption of BLB group was significantly higher than that of ITI and 3I groups at 3 and 12 months after implantation (P<0.05). Compared with the natural teeth, the gingival sulcus bleeding index of three groups were al increased at different time points after implantation;the gingival sulcus bleeding index of BLB group was significantly higher than that of natural teeth at 6 months after implantation (P<0.05);the gingival sulcus bleeding index of three groups were significantly higher than that of natural teeth at 9 months after implantation (P<0.05). The periodontal probing depth of three groups showed an ascending trend at 6 months after implantation;the periodontal probing depth of three groups was higher than that of natural teeth at different time points after implantation, which exhibited significant differences at 6 and 9 months after implantation (P<0.05). In conclusion, three kinds of dental implant systems exhibit differet effects on the peri-implant bone absorption, but al achieve excel ent clinical efficacies.

Objective To establish the golden hamster model of buccal squamous carcinoma and observe its biological character-istics .Methods 50 golden hamster were randomly divided into two group :experiment group (n=40) and control group(n=10) . Buccal mucosa of golden hamster were daubed by exposure 4-nitroquinoline-1-oxide (4NQO) in experiment group and tap water in control group .HE staining and immunohistochemistry were used to observe the tissue sample on the 8th and 12th week .The tissue samples of golden hamster buccal-mucosa cancer were used for the in-vitro subculture .Then flat cloning formation rate ,expression of CK and Vim ,and cell karyotype were detected .Results The observations of cell morphology and biology showed that the tissue of buccal squamous carcinoma were conformed to the basic characteristics of squamous carcinoma cell in 26 golden hamster(84 .6% ) after 12 weeks .The positive rate of CK and Vim were 96 .0% by immunohistochemical staining .The Chromosomes were tetraploid karyotype .Conclusion We successfully established the golden hamster model of buccal squamous carcinoma by the daub method of 4NQO .