Hydroxyapatite powder was mechanochemically synthesized from calcium pyrophosphate (Ca2P2O7) and calcium carbonate (CaCO3) using a solid-state reaction. The two powders were mixed in distilled water, milled for 8 hours, dried and calcined at 1100 degrees C for 1 hour. The phase(s) formed was analyzed by x-ray diffraction (XRD). It was found that hydroxyapatite was not the only one formed. This result will be used as the starting point to produce a single-phase hydroxyapatite in terms of excess hydroxyl group in a mechanochemical reaction.
The present paper reports on the influence of sintering temperature on the porosity and strength of porous hydroxyapatite (HA). HA powder was first prepared by the sol-gel precipitation method using calcium hydroxide and ortho-phosporic acid. The fine HA powder, measuring <50 microm was then mixed into a slurry with the addition of binder agent, being a mixture of sago and PVA. A small amount of sodium dodecyl sulphate was also used as a foaming agent. Porous HA samples were then prepared via slip casting technique. The surface morphology of the sintered samples was observed under scanning electron microscopy at 20 kV and the compositions were determined via SEM-EDX. A universal testing machine was used to determine the compaction strength of the sintered samples.
A mixture with different compositions of HA and TCP were synthesize in this work by precipitation method using Ca(NO3)2 4H2 and (NH4)2HPO4 as the starting materials. A mixture with HA and TCP phases in different ratios were produced. The powders were sintered from 1000 degrees C to 1250 degrees C. The phase compositions of the mixtures were then studied via XRD. This work shows that the pH value determines the different phase compositions of the HA-TCP mixture. Chemical analyses were carried out by FTIR. The microstructure was observed under SEM.
Biomaterials intended for end-use application as bone-graft substitutes have to undergo safety evaluation. In this study, we investigated the in vitro cytotoxic effects especially to determine the mode of death of two hydroxyapatite compounds (HA2, HA3) which were synthesized locally. The methods used for cytotoxicity was the standard MTT assay whereas AO/PI staining was performed to determine the mode of cell death in HA treated L929 fibroblasts. Our results demonstrated that both HA2 and HA3 were not significantly cytotoxic as more than 75% cells after 72 hours treatment were viable. Furthermore, we found that the major mode of cell death in HA treated cells was apoptosis. In conclusion, our results demonstrated that these hydroxyapatite compounds are not cytotoxic where the mode of death was primarily via apoptosis.
Hydroxyapatite is the main component of the bone which is a potential biomaterial substance that can be applied in orthopaedics. In this study, the biocompatibility of this biomaterial was assessed using an in vitro technique. The cytotoxicity and genotoxicity effect of HA2 and HA3 against L929 fibroblast cell was evaluated using the MTT Assay and Alkaline Comet Assay respectively. Both HA2 and HA3 compound showed low cytotoxicity effect as determined using MTT Assay. Cells viability following 72 hours incubation at maximum concentration of both HA2 and HA3 (200 mg/ml) were 75.3 +/- 8.8% and 86.7 +/- 13.1% respectively. However, the cytotoxicity effect of ZnSO4.7H2O as a positive control showed an IC50 values of 46 mg/ml (160 microM). On the other hand, both HA2 and HA3 compound showed a slight genotoxicity effect as determined using the Alkaline Comet Assay following incubation at the concentration 200 mg/ml for 72 hours. This assay has been widely used in genetic toxicology to detect DNA strand breaks and alkali-labile site. The percentage of the cells with DNA damage for both substance was 27.7 +/- 1.3% and 15.6 +/- 1.0% for HA2 and HA3 respectively. Incubation of the cells for 24 hours with 38 microg/ml (IC25) of positive control showed an increase in percentage of cells with DNA damage (67.5 +/- 0.7%). In conclusion, our study indicated that both hydroxyapatite compounds showed a good biocompatibility in fibroblast cells.
The present study is aimed at finding the mutagenicity and cytotoxicity of dense form of synthetic hydroxyapatite (Source: School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia) in the blood of sheep. The biomaterial was implanted in the tibia of Malin, an indigenous sheep breed of Malaysia. Blood was collected from the sheep before implantation of the biomaterial, cultured and a karyological study was made. Six weeks after implantation, blood was collected from the same animal, cultured and screened for chromosome aberrations. The mitotic indices and karyological analysis indicated that the implantation of synthetic hydroxyapatite (dense form) did not produce any cytotoxicity or chromosome aberrations in the blood of sheep.
There has been, and is still, concern about the high elastic modulus of Ti alloys compared to bone. Any reduction in the Young's modulus value of the implant is expected to enhance stress redistribution to the adjacent bone tissues, minimize stress shielding and eventually prolong device lifetime. Dynamic Monte Carlo simulation is used to predict the gradual reduction in Young's modulus values between the bulk of Ti alloys and the modified surface layers due to Ca ion implantation. The simulation can be used as a screening step when applying new alloys and/or coatings.
In this work, nanometer HA crystals have been synthesized via wet chemical precipitation and characterized. This research studies how key synthesis parameters affect the size and phase purity of the produced HA. Characterization work was carried out using X-ray powder diffraction method and scanning electron microscopy for phase identification and particle sizing, respectively.
A study was conducted to investigate the effectiveness of freeze-dried bovine pericardium (FDBP) as a biomaterial in diaphragmatic herniorrhapy in dogs. Eight adult dogs were randomly selected and divided into two equal groups. In FDBP group, a diaphragmatic defect was induced and repaired with an identical size of FDBP. In the control group, a diaphragmatic wall was incised at three-side border creating a flap and sutured. Grossly, only mild intrathoracic adhesion was observed for most of the animals, and no herniation occured. Microscopically, the biomaterial incorporated into the host's tissue by ingrowth of young muscle fiber and massive new blood vessel formation in between the fibrous tissue.
Metallic materials implanted into bone defects are generally encapsulated by a fibrous tissue. Some metallic materials such as titanium and tantalum, however, have been revealed to bond to the living bone without forming the fibrous tissue, when they were subjected to NaOH solution and heat treatments. Thus treated metals form bone tissue around them even in muscle, when they take a porous form. This kind of osteoconductive and osteoinductive properties are attributed to sodium titanate or tantalate layer on their surfaces formed by the NaOH and heat treatments. These layers induce the deposition of bonelike apatite on the surface of the metals in the living body. This kind of bioactive metals are useful as bone substitutes even highly loaded portions, such as hip joint, spine and tooth root.
One of the emerging technologies in the area of plasma processing is plasma immersion ion implantation (PSII). The paper addresses the merits offered by the PSII technique especially in the area of biomaterial processing. Worldwide development status as well as the drive towards commercial applications is elaborated in an attempt to draw the attention to the importance of the process for Malaysia as well as south East Asia.
Missing teeth can be due to hypodontia, trauma or extraction. In general, the options for treatment depend on the severity of the hypodontia and the severity of the malocclusion. Occasionally, the space from missing teeth has to be maintained for prosthetic replacement and require an orthodontic/restorative approach. It is very important to ensure the space maintained is adequate for aesthetic reason so that it can be replaced with a prosthesis after the orthodontic treatment is completed. This article discusses a new innovation and clinical technique for maintaining this space during orthodontic treatment by using an acrylic tooth with several modifications. This innovation will be illustrated using two cases.
The calcareous rings of two species of local sea cucumbers, Stichopus hermanni Semper and Holothuria atra Jaeger, were located, dissected, exposed and recorded. The calcareous rings of both species each composed of ten plates knit together by connective tissues. The radial plate of H. atra was a square with a notch at the anterior part whereas in S. hermanni it was squarish consisting of 4 ridges in the anterior part with a notch at the posterior part. The interradial plates of both species were smaller than the radial plates. A ridge was present at the anterior part of the interradial plate in H. atra. In S. hermanii, the ridge at the anterior part of the interradial was thin and prominent. Under the scanning electron microscope the calcareous rings from the two species exhibited a mosaic of small, numerous spicules bound to each other.
Most prosthetic joint infections originate from wound contamination or haematogenous seeding from distant sites of infection. Bacteraemia may follow dental treatment but there is little evidence of it related to prosthetic joint infection. Nevertheless, controversy continues with regards to the effect of dental treatment in patients with prosthetic joints. This article reviews current English literature regarding the use of antibiotic prophylaxis in the dental management of patients with prosthetic joints. Routine antibiotic prophylaxis is not recommended for every patient with prosthetic joints when receiving dental treatments. However, antibiotic prophylaxis may be prescribed for high-risk groups with predisposing factors to infection when undergoing dental treatment with high risk of bacteraemia.
We report two cases of large chest wall primary chondrosarcoma, one of the sternum and the other of the lateral chest wall. Both were treated by radical resection and reconstruction using marlex mesh and methyl methacrylate "sandwich" prosthesis and pedicled latissiumus dorsi flap.
Two hundred eleven patients with small- to moderate-sized native patent ductus arteriosus underwent closure using Gianturco coils, employing the transvenous multiple catheter approach. Short-term results showed a high rate of complete occlusion and a potential long-term complication of mild left pulmonary artery stenosis in a small number of patients.
This paper reports a case of double orifice mitral valve which was treated conservatively. A new scheme of classification of this entity linked to the accepted lines of surgical treatment is introduced.
Oroantral fistula is an uncommon complication in oral surgery. Although smaller fistulas of less than 5 mm in diameter may close spontaneously, larger fistulas always require surgical closures. The literature review revealed various procedures for the closure of oroantral fistulas. These procedures may be subdivided into local flap, distant flap and grafting. Procedures involving local flaps are usually adequate to close minor to moderate size defects. Those procedures utilizing the buccal mucoperiosteal flap as the tissue closure include straight-advancement, rotated, sliding and transversal flap procedures; while those involving the palatal mucoperiosteum are straight advancement, rotational-advancement, hinged and island flap procedures. The combinations of various local flaps to strengthen the tissue closure are also being advocated. The advantages and the limitations of these procedures are discussed. Distant flaps and bone grafts are usually indicated in the closure of larger defects in view of their greater tissue bulks. Tongue flaps have superseded extra-oral flaps from extremities and forehead for aesthetic reasons and also in view of their similar tissue replacement. Various tongue flap procedures are described. At present, various alloplastic materials such as gold, tantalum and polymethylmethacrylate are infrequently reported in the closure of oroantral fistulas. However, in the light of successful reports over the use of biological materials, collagen and fibrin, in the closure of oroantral fistulas, there seems to be another simple alternative technique for treating oroantral fistulas.