Facial soft tissues are a major determinant of treatment choice. When Class I and Class II malocclusions were compared using finite-element analysis, morphologic differences were localized and quantified. This study highlights the importance of determining the timing, magnitude and direction offacial growth prior to treatment to achieve stable results.
The role of protein kinase C (PKC) in hydroxyapatite (HA)-induced phagocytosis by RAW 264.7 cells was investigated. The cells were incubated with HA particles at various incubation time and the levels of PKC activity were determined from the cell lysate. To determine the role of PKC, particles were incubated with the cells pretreated with the various concentrations of bisindolylmaleimide, a PKC inhibitor, and phagocytosis was then assessed at 60 min. Latex beads were used as a control. Our results showed that following incubation with HA particles, the levels of PKC activity in RAW264.7 cells was highest at 7 min and then decreased to reach the baseline levels of the controls at 30 min. Pretreatment of the cells with bisindolylmaleimide significantly reduced phagocytosis of HA particles in a dose-dependent pattern. The results of our present study suggest therefore that ingestion of HA by RAW264.7 cells may depend on PKC activity that may act in the early stages of phagocytosis.
Human amniotic membrane as a homograft material was compared to temporalis fascia to close tympanic membrane perforations in 50 patients with chronic otitis media. Human amniotic membrane was used in 20 patients while temporalis fascia was used in the remaining 30. Anatomical closure of the perforation and reduction of the air-bone gap was measured. The graft uptake showed a 65% success rate for the amniotic membrane and 56.7% for the temporalis fascia at 3 months post-operatively. Significant closure of air-bone gap was observed in the human amniotic group. These results indicate comparable outcomes between human amniotic membrane and the temporalis fascia graft.
Presurgical orthopaedics has been employed since the 1950s as an adjunctive neonatal therapy for the correction of cleft lip and palate. It is accepted that presurgical orthopaedic plates facilitate lip repair and balanced orofacial growth.
We report a case of a 6 month old baby boy who had congenital nasal encephalocele, repaired via the traditional staging procedure. The surgical techniques and procedures are described and discussed.
This study was done to determine the prevalence of dental anomalies and facial profile abnormality and its association with the non-syndromic cleft lip and palate (CLP) as compared to the non-cleft children. A comparative cross sectional study was conducted where the case group consist of 98 non-syndromic CLP children-unilateral (UCLP) and bilateral (BCLP) who attended the Combined Clinic at Kota Bharu Dental Clinic (KBDC) while the comparison group comprised of 109 non-cleft children who attended the outpatient clinic at KBDC. Their ages were between 3 to 12 years old. Clinical oral and facial profile examinations were carried out to look for dental anomalies (morphology, number and alignment of teeth) and facial profile abnormality. The prevalence of anomalies in morphology of teeth in CLP (24.5%) and non-cleft (10.1%), number of teeth in CLP (44.9%) and non-cleft (7.3%), mal-alignment in CLP (79.6%) and non-cleft (27.5%) and facial profile abnormality in CLP (26.5%) and non-cleft (9.1 %). There was a significant association between CLP and anomalies in morphology, number, mal-alignment and abnormality in facial profile; (p < 0.05). Therefore, there was a high prevalence and risk of dental anomalies and facial profile abnormality in the CLP children compared to the non-cleft children.
In this study the surface properties of two particulate coral and polyhydroxybutrate (PHB) were studied in order to characterize them prior to use in composite production. Coral powder and PHB particle were evaluated using scanning electron microscopy and confocal laser scanning microscopy, to measure surface porosity and pores size. The results showed that coral powder has multiple pleomorphic micropores cross each others give appearance of micro-interconnectivity. Some pore reached to 18 microm with an average porosity of 70%. PHB revealed multiple different size pores extended to the depth, with an average some times reach 25 microm and porosity 45%. These findings demonstrate that both coral and PHB have excellent pores size and porosity that facilitate bone in growth, vascular invasion and bone development. We believe that incorporation of coral powder into PHB will make an excellent composite scaffold for tissue engineering.
The aim of this study was to evaluate the in vitro cytotoxicity of biomaterials; Hydroxyapatite (HA), Natural coral (NC) and Polyhydroxybutarate (PHB). Three different materials used in this study; HA (Ca10(PO4)6(OH)2), NC (CaCO3) and PHB (Polymer) were locally produced by the groups of researcher from Universiti Sains Malaysia. The materials were separately extracted in the complete culture medium (100mg/ml) for 72h and introduced to the osteoblast cells CRL-1543. The viability of osteoblast CRL-1543 cultivated with these extraction materials after 72h incubation period was compared to negative control with neutral red assay by using spectrophotometer at 540nm. The results showed the non-cytotoxicity of the materials. After 72h of incubation period, HA showed 123% viable cells, NC was 99.43% and PHB was 176.75%. In this study, cytotoxicity test dealt mainly with the substances that leached out from the biomaterial. The results obtained showed that the materials were not toxic and also promoted cells growth in the sense of biofunctionality.
The aim of this study was to evaluate the morphological and biological properties of a locally produced "Bovine Bone Sponge" for use in dentistry. Bovine bone sponge was prepared from local calf bone. Endotoxin level and surface properties were investigated. The pore size and water uptake ability were measured and results were compared with the commercial haemostatic agent. The material was tested for its haemostatic property and its inhibition of alveolar bone resorption in a sheep model following dental extraction. Results revealed a significant difference in haemostatic effect, and a shorter bleeding time and a lower rate of alveolar bone resorption in bovine bone sponge compare to a commercial haemostatic agent.
The aim of this study was to evaluate the mechanical properties and glass transition temperature (Tg) of a denture base material prepared from high molecular weight poly methyl methacrylate (PMMA) and alumina (Al2O3). The glass transition temperature was studied by using differential scanning calorimetry (DSC). The effect of powder-to-liquid ratio was investigated. The result showed that the tensile properties and the Tg were slightly effected by the powder-to-liquid ratio. The ratio of 2.2:1 by weight of powder to liquid was found to be the best ratio for mixing the material to give the best result in this formulation.
This in vivo study revealed that porous hydroxyapatite (PHA) and dense hydroxyapatite (DHA) are good implant materials that can accelerate bone healing and resorbed in acceptable time. But there were differences in the mechanism of the resorption of DHA and PHA due to variability in the physical properties and osteogenicity.
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.
In Malaysia, the field of genomics in toxicology is still in infancy. The purpose of this study is to focus on the use of toxicogenomics for determination of gene expressions changes in cultured human fibroblast cells treated with genotoxicology free biomaterial (using Ames test), a locally produced hyroxyapatite. Dose and time response is similar to Ames test with time interval up to 21 days. mRNA is extracted, followed with RT-PCR and polyacrilamide gel electrophoresis. Changes of the gene expressions compared to the non-treated fibroblast mRNA would suggest some gene interactions in the molecule level associated with the exposure of the fibroblast cell line to the biomaterials. Further analysis (cloning & sequencing) shall be carried out to investigate the genes involved as simple changes might not signified toxicity.
The aim of this study was to evaluate the tensile properties and water absorption of denture base material prepared from high molecular weight poly methyl methacrylate (PMMA) and alumina (Al2O3) as particulate filler. Specimens for mechanical testing were prepared by adding composite powder to the monomer followed by hand mixing as in dental laboratory procedure. The tensile strength of the prepared denture base material was slightly higher than commercial denture base material, while the water absorption was almost the same for all formulation of denture base materials.
The human fibroblast MRC-5 cells incubated with PHB granules (TM) added at a final concentration of 4 mg/ml showed a time-course pattern of survival. The percentages of dead cells obtained were at the rate of 3.8% after 7 days, respectively. When the MRC-5 cells grown in different material, using the test concentration of 4 mg/ml PCM, they were found to show a similar time-course increasing pattern of death as that obtained with PHB. However, the death was noted in the cells incubated for 7 days, the death rates obtained was 40.54% respectively.
Defects were created in the mandible of a rabbit model whereby the right side was implanted with hydroxyapatite (HA) while the left side was left empty to act as control. Both the implant and control sites were evaluated clinically and histologically at 4,12,20,22 weeks. Decalcified sections were studied under confocal laser scanning microscope. No reactive cells were evident microscopically in all sections. There was bone ingrowth as early as 4 weeks when viewed by the topographic method. Enhancement of osteoconduction was evident by the presence of abundant capillaries, perivascular tissue and osteoprogenitor cells of the host. At 22 weeks, the implanted defect showed mature bone formation filling almost the whole field. This study demonstrated that the dense HA exhibits excellent biocompatibility as noted by the complete absence of reactive cells. It also promotes osteoconduction.
This study evaluates the cytotoxic and mutagenic effect of synthetic hydroxyapatite granules (source: School of Material and Mineral Resources Engineering, Universiti Sains Malaysia) in the bone marrow cells of mice. Mice are exposed to synthetic hydroxyapatite granules, the bone marrow cells are collected and observed for chromosome aberrations. No chromosome aberrations were noticed in the animals exposed to distilled water (negative control) and to the test substance, synthetic hydroxyapatite granules (treatment) groups. Chromosome aberrations were observed in the animals exposed to Mitomycin C (positive control group). There was no indication of cytotoxicity due to synthetic hydroxyapatite granules in the animals as revealed by the mitotic index. Hence, synthetic hydroxyapatite granules are considered non-mutagenic under the prevailing test conditions.
There was a significant increased in Absolute Contact Length measurements of endosteal bone growth along the Nickel-Titanium (NiTi) implant coated with the natural coral powder and Hydroxyapatite (HA) compared to the non-calcium coated implants. This study demonstrated that coated implants seemed to show earlier and higher osseointergration phenomena compared to non coated ones. Furthermore, there was significantly greater bone-to-implant contact at the apical 1/3rd of the coated implants.
The main objective of the study was to determine the biodegradability, resorption and osteoconductivity potency of coral implant. Coral blocks (CORAGRAF) were prepared from sea coral Porites species. The blocks were implanted in the right mandible of rabbit model. Implants were harvested at 2 and 4 weeks intervals and subjected for light and scanning electron microscopy. Dense hydroxyapatite (DHA) was implanted in the left mandible as a control. The results of this study demonstrated that CORAGRAF is a good implant material that can accelerates bone healing and be resorbed in an acceptable time. The mechanisms of the resorption seemed to be the same (crumbling process), a first step where the edge of the coral become powdery then a second step which could be phagocytosis and dissolution in extracellular fluid.