Tissue engineering using human mineralized bone xenograft and bone marrow mesenchymal stem cells allograft in healing of tibial fracture of experimental rabbit model

Bone healing and its reconstruction in fractures, especially in long bones are of particular importance in regenerative medicine. This study compares the bone healing rate after a human xenograft of mineralized bone and together with an allograft of bone marrow mesenchymal stem cells [MSCs] in an experimental tibial bone fracture rabbit model. In fall 2009, twenty New Zealand white rabbits were randomly divided into 2 equal groups. In both groups, a 5 mm segmental defect was created in the right tibia. In group A, a scaffold pin was seeded with allogenic rabbit MSCs and was placed in the defect area and in group B, the defect was filled with an unseeded pin human mineralized bone xenograft. An untreated defect was induced in the left tibia of all animals serving as the control. After 4-8 weeks, the segmental defects were histologically evaluated and also by a compressive test. In groups A and B, healing and formation of new bony tissue were significantly more than the control group and with a significant less inflammation. Tissue engineering of mineralized bone xenograft and MSCs allograft may be significant steps in bone healing and regenerative medicine

Effect of water on HEMA conversion by FT-IR spectroscopy

The use of HEMA as a biocompatible material in dentin bonding systems and its potential for clinical applications has been well established. Excess water can affect conversion of bonding resins. The aim of this study was to survey the effect of water on the degree of conversion of HEMA by Fourier Transform Infra-red Spectroscopy [FT-IR]. In this experimental study, distilled water was added in amounts of 0, 0.05, 0.1, 0.2, and 0.4 ml to 1 ml of curable HEMA solution. Six repetitions per water ratio were made and investigated. Each sample was polymerized for 60 seconds. Degree of conversion was obtained from the absorbance IR-Spectrum of the materials before and after polymerization by FT-IR spectroscopy. One way ANOVA and Tukey-HSD were carried out to compare and detect any differences among groups. Statistical analysis indicates highly significant difference between pairs of groups at level [P<0.001]. The results showed a trend of decreasing in HEMA conversion with increasing water. Degree of conversion changes significantly within the 0.05 ml to 0.2 ml water range. However, degree of conversion did not change after reaching 0.02 ml and before 0.05. Degree of conversion of HEMA decreased by increasing water. The most dramatic effect of water on the polymerization process occurs within a range which exists under clinical conditions. The reason that the degree of conversion did not show significant result before 0.05 ml may be related to the hydrophilic nature of HEMA