ABSTRACT
OBJECTIVE: The aim of this study was to investigate the effects of the freeze drying and solvent dehydration allograft preservation methods on the mechanical properties of the graft material. METHODS: Bone blocks obtained from bovine humeri were divided into three groups. Samples in the first group were freeze dried, samples in the second group were dehydrated by solvents and samples in the third group were used as controls. All samples underwent three point bending test to investigate bending strength and were evaluated for calcium content. RESULTS: Bending strength of both the freeze-dried and solvent-dehydrated samples were found to have decreased significantly compared to that of the control group. The calcium content of the solvent dehydrated group was also significantly lower than that of the control group. CONCLUSION: Our results suggested that both preservation techniques, used to dehydrate bone, have negative effects on the bending strength of bone as they decrease the mechanical properties of the graft material.
Subject(s)
Bone Transplantation/methods , Calcium/metabolism , Desiccation/methods , Freeze Drying/methods , Preservation, Biological/methods , Animals , Cattle , Femur/surgery , Male , Models, Animal , Random Allocation , Risk Factors , Sensitivity and Specificity , Solvents/chemistry , Stress, Mechanical , Tensile Strength , Transplantation, HomologousABSTRACT
PURPOSE: This study has the objective to evaluate the lead(II) removal capacity of hydroxyapatite powder synthesized by microwave as an alternative method to decrease production time and cost. METHODS: Hydroxyapatite (HA) was synthesized by a microwave-assisted precipitation method using calcium nitrate and ammonium hydrogen phosphate as calcium and phosphorus sources, respectively. X-ray diffraction and Fourier transform infrared results clearly revealed that the resulting powder was HA with high purity and crystallinity. The obtained powder was used for the removal of lead(II) from aqueous solutions. The effects of pH, amount of adsorbent, initial lead(II) concentration, and contact time were studied in batch experiments. RESULTS: In the adsorption experiments, maximum lead(II) retention was obtained at pH 6. Adsorption equilibrium was established after 40 min. It was found that the adsorption of lead(II) on HA was correlated well (R (2) = 0.958) with the Freundlich equation for the concentration range studied. Both ion exchange and adsorption process were thought to exist in the removal process. CONCLUSIONS: This study indicates that easily and rapidly synthesized HA by microwave-assisted precipitation method could be used as an efficient adsorbent for removal of lead(II) from aqueous solutions.
Subject(s)
Durapatite/chemical synthesis , Lead/chemistry , Water Pollutants, Chemical/chemistry , Water Purification/methods , Adsorption , Chemical Precipitation , Hydrogen-Ion Concentration , Microscopy, Electron, Scanning , Microwaves , Time Factors , Water/chemistry , X-Ray DiffractionABSTRACT
The aim of this study was to evaluate, in vitro, the early tensile bond strength values of three dentin bonding agents (Scotchbond, Tenure and Gluma) to dentin. Fifteen non-carious, extracted, human third molars were used in this study. The bond strengths were calculated in an Instron test machine and expressed in MN/m². The results were evaluated statistically using the Syudentt-test. The in vitro tensile bond strengths of the three bonding agents to dentin showed higher values than the tensile bond strength of composite resin alone and differences among the bond strengths were significant (P<0.05). Greater bond strength values were obtained with the Gluma bonding system than with Scotchbond or Tenure systems