title: Mechanical and biological evaluations of beta-tricalcium phosphate/silicone rubber composite as a novel soft-tissue implant.
abstract: BACKGROUND
  Although silicone rubber (SR) implants are most commonly used and effective for soft-tissue augmentation, they still have been implicated in many adverse reactions. To overcome this problem, a novel composite beta-tricalcium phosphate/silicone rubber (beta-TCP/SR) was prepared by adding beta-TCP into a SR matrix. This study was to evaluate its application potential by investigating the mechanical properties and biocompatibility of beta-TCP/SR.
  
  
  METHODS
  Mechanical properties, including Shore A hardness and tensile strength, were evaluated with 3-mm-thick samples and a universal testing machine. Cytocompatibility tests were conducted in vitro using 0.2-mm-thick beta-TCP/SR samples by seeding fibroblasts onto different samples. Soft-tissue response to beta-TCP/SR and pull-out measurements were investigated 4 weeks and 24 weeks after implantation.
  
  
  RESULTS
  The main mechanical properties were all significantly changed after mixing beta-TCP into the SR matrix, except for tearing strength. The cytocompatibility test showed enhanced adhesion and proliferation of fibroblasts onto beta-TCP/SR. Fibrous tissue ingrowth after resorption of beta-TCP was observed by in vivo histologic analysis. The peri-implant capsules in the beta-TCP/SR group were thinner than in the SR group 24 weeks after implantation. In a 24-week test, the maximum force required to pull out the beta-TCP/SR sheet was about six times greater than that needed for SR.
  
  
  CONCLUSIONS
  Although some mechanical properties were significantly changed, the results of the cytocompatibility test and in vivo animal study still suggest that beta-TCP/SR may be more suitable as a soft-tissue implant than SR and has the potential to be used in plastic surgery.
authors.affiliation: Department of Plastic and Cosmetic Surgery, Xinqiao Hospital, Third Military Medical University, Xinqiao Road, Sha Ping Ba District, Chongqing, 400037, China.
authors.forename: Yi-ming
authors.initials: YM
authors.lastname: Zhang
authors.forename: Shao-liang
authors.initials: SL
authors.lastname: Wang
authors.forename: Ze-yuan
authors.initials: ZY
authors.lastname: Lei
authors.forename: Dong-li
authors.initials: DL
authors.lastname: Fan
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology; D001696:Biomechanical Phenomena; D002130:Calcium Phosphates / Q000494:pharmacology*; D019245:Compressive Strength; D004195:Disease Models, Animal; D005347:Fibroblasts / Q000166:cytology / Q000473:pathology; D007150:Immunohistochemistry; D008297:Male; D008422:Materials Testing / Q000379:methods*; D011336:Probability; D019736:Prostheses and Implants; D011474:Prosthesis Design; D019919:Prosthesis Implantation; D011817:Rabbits; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012826:Silicone Elastomers / Q000494:pharmacology*; D013518:Surgery, Plastic / Q000379:methods; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D002130:Calcium Phosphates; D012826:Silicone Elastomers; C485817:beta-tricalcium phosphate