ABSTRACT
The purpose of this study was to investigate whether the use of HLA as an aqueous binder of hydroxyapatite/beta-tricalcium phosphate (HA-ßTCP) particles can reduce the amount of bone graft needed and increase ease of handling in clinical situations. In this study, HA/ßTCP was loaded in commercially available crosslinking HLA to form a novel HLA/HA-ßTCP composite. Six New Zealand White rabbits (3.0-3.6 kg) were used as test subjects. Four 6 mm defects were prepared in the parietal bone. The defects were filled with the HLA/HA-ßTCP composite as well as HA-ßTCP particle alone. New bone formation was analyzed by micro-CT and histomorphometry. Our results indicated that even when the HA-ßTCP particle numbers were reduced, the regenerative effect on bone remained when the HLA existed. The bone volume density (BV/TV ratio) of HLA/HA-ßTCP samples was 1.7 times larger than that of the control sample at week 2. The new bone increasing ratio (NBIR) of HLA/HA-ßTCP samples was 1.78 times higher than the control group at week 2. In conclusion, HA-ßTCP powder with HLA contributed to bone healing in rabbit calvarial bone defects. The addition of HLA to bone grafts not only promoted osteoconduction but also improved handling characteristics in clinical situations.
Subject(s)
Bone Diseases/therapy , Bone Regeneration , Bone Substitutes/chemistry , Bone and Bones/diagnostic imaging , Bone and Bones/pathology , Disease Models, Animal , Hydroxyapatites/chemistry , Animals , Bone and Bones/surgery , Osteogenesis , Powders , Rabbits , Skull/pathology , X-Ray MicrotomographyABSTRACT
This study examines the relationship between the retention force and natural frequency of dental posts cemented with zinc phosphate cement. Forty-two decoronated maxillary incisors were collected and embedded in resin blocks. The 7-mm post spaces were prepared for all test samples prior to cementing the 13-mm Para-Posts with zinc phosphate cement. The natural frequency values and retention forces of the zinc phosphate cement-cemented Para-Posts in various liquid/powder mixing ratios were measured. Thereafter, the natural frequency values of the zinc phosphate cement-cemented posts were continuously detected during ultrasonic vibration. Moreover, both the natural frequency values and the dislodgement forces in response to ultrasonic vibrations were measured for the pretreated post samples. Results showed that the natural frequency values of the posts significantly decreased from 8.8 ± 0.8 to 5.0 ± 0.5 kHz (P < 0.05) before and after ultrasound treatment, respectively. The natural frequency values and the dislodgement forces of tested posts had a highly linear relationship (R² = 0.99, P < 0.05). These findings suggest that natural frequency is a variable for monitoring the stability status of zinc phosphate cement-cemented dental posts.
Subject(s)
Dental Prosthesis Retention , Zinc Phosphate Cement/chemistry , Finite Element Analysis , Humans , Incisor/chemistry , Incisor/diagnostic imaging , Incisor/surgery , Linear Models , Mechanical Phenomena , Models, Biological , Root Canal Preparation , Ultrasonography , VibrationABSTRACT
In this study, hydrogels composed of polyethyleneimine (PEI) and poly(vinyl pyrrolidone) K90 (PVP) cross-linked with various concentrations (0, 0.125, 0.25 and 0.5%) of glutaraldehyde were evaluated as a hydrogel filler for the local delivery of lidocaine after tooth extraction. The drug-release kinetics, swellability, cytotoxicity and wound healing after tooth extraction of these non-cross-linked and cross-linked PEI-PVP hydrogels were examined in male beagles and compared to values using Spongostan(®). Results demonstrated that the extent of cross-linking influenced the swelling of the resulting hydrogel, but the drug-release rates were similar. No significant changes were observed in gingival fibroblasts in contact with the PEI- PVP hydrogels or Spongostan(®). In the in vivo study, PEI-PVP hydrogels showed good retention in the socket for 2 days and showed comparable wound-healing rates within 2 weeks with those of Spongostan(®). In conclusion, PEI-PVP hydrogels are suitable for use as socket-dressing materials, and the release of local anaesthesia from PEI-PVP hydrogels can be sustained for a desirable period of time to prevent pain after a tooth extraction.
Subject(s)
Dental Materials , Drug Delivery Systems , Hydrogels , Imines , Polyethylenes , Povidone , Tooth Extraction , Anesthetics, Local/administration & dosage , Anesthetics, Local/pharmacokinetics , Animals , Bandages , Cell Survival , Cross-Linking Reagents/chemistry , Dental Materials/chemical synthesis , Dental Materials/chemistry , Dogs , Drug Liberation , Fibrin Foam , Fibroblasts/drug effects , Fibroblasts/physiology , Gingiva/drug effects , Gingiva/injuries , Gingiva/physiopathology , Glutaral/chemistry , Hydrogels/chemical synthesis , Hydrogels/chemistry , Imines/chemistry , Lidocaine/administration & dosage , Lidocaine/pharmacokinetics , Male , Models, Animal , Polyethylenes/chemistry , Povidone/chemistry , Wound HealingABSTRACT
This study investigated the effects of static magnetic fields on the differentiation of MG63 cells cultured on the surface of poly-L-lactide (PLLA) substrates. The cells were continuously exposed to a 4,000 Gauss-static magnetic field (SMF) for 5 days. The proliferation effects of the SMF were measured by MTT assay. Morphologic changes and extracellular matrix release were observed by scanning electron microscopy. The effects of the SMF on alkaline phosphatase activity levels were compared between exposed and unexposed cells. The SMF-exposed cells exhibited decreased MTT values after 1 and 3 days of culture. In addition, SMF exposure promoted the expression of extracellular matrix in MG63 cells on the PLLA substrate. After 1 day, the alkaline phosphatase-specific activity of SMF-exposed MG63 cells was significantly increased (P < 0.05) with a ratio of 1.5-fold. These results show that MG63 cells, seeded on a PLLA disc and treated with SMF, had a more differentiated phenotype.
