Papers by Author: T. Yuan

Abstract: This study was carried out to investigate the effect of acid-alkali treatment and alkaliheat treatment on the push-out strength and tissue response of the porous titanium in vivo. Porous titanium with different treatment was implanted in dog bony site for 2 months and 5 months and the push-out strength was tested. At 2 months, the mean push-out strengths of the acid-alkali treated and alkali-heat treated porous titanium were 11.3 and 15 MPa, respectively. At 5 months, the values reached 29.8 and 35 MPa, respectively. Histological observation showed a close contact between implants and bone, and more bone tissue filled inside the pores of porous titanium increasing with implantation time. The results indicated higher bonding strength between bone and porous titanium in alkali-heat treated samples. Therefore, alkali-heat treatment can provide porous titanium implants with better fixation as a bone substitute for clinical use under load-bearing conditions.

Abstract: Serum immersion, a new method of pre-treated HA ceramics, has been compared with SBF immersion and untreated HA particles in cell culture condition. MTT assay indicates that serum-immersion lessens particles cytotoxity of HA particles in cultured L929 mouse fibroblast cell (p<0.05). Neither immersion nor traditional physical factors such as particle size, shape should be responsible for these because SBF immersion with the similar factors results in no significant improvement. The reason might be serum proteins adsorption and biommetic microstructure formation on the ceramics surface, which affect cellular membrane behaviors, phagosome metabolization and cellular protein secretion. Otherwise, cells with particles degraded early apparently, which indicated that particles influence the cell cycle. The whole processes must be correlated intensively with cytokine, protease and intracellular ion concentration, which would be discussed in our follow-up studies.

Abstract: Biological sealing is a key factor for successful development of percutaneous device (PD). A new device with arc-perforated flange as subcutaneous part and groove-shaped percutaneous part, was intended to improve integration of soft tissue and implant. Material and surface properties are known to have great impact on tissue-implant integration. To understand how a material and its surface property can influence tissue reaction, and to find the appropriate material for PD fabrication, five different kinds of materials were prepared for in vivo animal tests with corresponding histological evaluation. Results revealed that a more stable junction was formed between the soft tissue and HA coated titanium implant than other combinations.