title: The effect of varying the particle size of beta tricalcium phosphate carrier of recombinant human bone morphogenetic protein-4 on bone formation in rat calvarial defects.
abstract: BACKGROUND
  Beta tricalcium phosphate (beta-TCP) has been developed as one of the carriers of recombinant human bone morphogenetic protein (rhBMP). However, it is not known whether the particle size of beta-TCP is related to its resorption rate and the degree of bone formation. The purpose of this study was to evaluate the effect of using beta-TCP with different particle sizes on the ability of rhBMP-4 to enhance bone formation in the rat calvarial defect model.
  
  
  METHODS
  Calvarial, 8-mm-diameter, critical-size defects were created in 100 male Sprague-Dawley rats. Five groups of 20 animals each received either rhBMP-4 (2.5 microg) using beta-TCP with a particle size of 50 to 150 microm, rhBMP-4 (2.5 microg) using beta-TCP with a particle size of 150 to 500 microm, a beta-TCP control with a particle size of 50 to 150 microm, a beta-TCP control with a particle size of 150 to 500 microm, or a sham-surgery control, respectively, and were evaluated by measuring their histologic and histometric parameters following a 2- and 8-week healing interval.
  
  
  RESULTS
  There were no significant differences in the defect closure, new bone area, or augmented area between either the two rhBMP-4/beta-TCP groups or between the two beta-TCP control groups at 2 and 8 weeks.
  
  
  CONCLUSIONS
  rhBMP-4 combined with either small- or large-particle beta-TCP had a significant effect on the induction of bone formation compared to either a small- or large-particle beta-TCP control or a sham-surgery control. Within the parameters of this study, varying the particle size of beta-TCP did not seem to have a significant effect on bone formation.
authors: Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, Seoul, Korea.
authors: Ui-Won
authors: UW
authors: Jung
authors: Seong-Yong
authors: SY
authors: Choi
authors: Eun-Kyoung
authors: EK
authors: Pang
authors: Chang-Sung
authors: CS
authors: Kim
authors: Seong-Ho
authors: SH
authors: Choi
authors: Kyoo-Sung
authors: KS
authors: Cho