The aim of this study was to evaluate the effect of powder-to-liquid ratio on the glass transition temperature (Tg) and the tensile properties of denture base material prepared from poly (methyl methacrylate) (PMMA) and hydroxyapatite (HA) previously treated with 3-trimethoxysilylpropyl methacrylate (gamma-MPS). Specimens for mechanical testing were prepared by adding composites powder (PMMA, BPO and HA) to the monomer (MMA and EGDMA) followed by hand mixing as in dental laboratory description usage. The glass transition temperature was studied by using differential scanning calorimetry (DSC). It was observed that the tensile properties and the Tg were affected by the powder-to-liquid ratio. The mechanical characterization of the materials were performed by using single edge notch-tension (SEN-T) specimens; the fracture toughness was slightly higher in formulation which contained HA filler compared to commercial denture base material.
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.
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.
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.
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.
The aim of this study was to determine the role of nitric oxide (NO) in hydroxyapatite (HA)-induced phagocytosis by a murine macrophage cell line (RAW264.7). The cells were incubated with HA particles at various incubation time and phagocytosis was assessed using phagocytic index (PI). NO production from the culture supernatants was determined by the Griess reagent. The inducible nitric oxide synthase (iNOS) expression was determined by Western blot. The particles were also incubated with cells pretreated with various concentrations of L-N(6)-(1-iminoethyl) lysine hydrochloride (L-NIL) or L-arginine. Latex beads were used as a control. Our results showed that macrophage phagocytosis induced by HA was higher than that induced by the beads. However, NO production by HA-stimulated cells was lower than that by bead-stimulated cells. iNOS expression in both bead- and HA-stimulated cells was observed expressed at 7, 15, 30, and 60 min. l-Arginine enhanced but l-NIL inhibited both phagocytosis and NO production by HA-stimulated cells. The results of the present study suggest that nitric oxide may play a crucial role in HA-induced phagocytosis by RAW264.7 cells.
The aim of the present study was to determine the effect of nitric oxide (NO) on the production of prostaglandin E2 (PGE2) by a human osteoblast cell line (HOS cells) stimulated with hydroxyapatite. Cells were cultured on the HA surfaces with or without the presence of NO donors (SNAP and NAP) for 3 days. The effect of NO scavenger, carboxy PTIO, or endothelial nitric oxide synthase (eNOS) inhibitor, L-NIO, was assessed by adding this scavenger in the cultures of HA-stimulated HOS cells with or without the presence of SNAP. Furthermore, HOS cells were pre-treated with anti-human integrin alphaV antibody, indomethacin, a non-specific inhibitor, aspirin, a COX-1 inhibitor, or nimesulide, a COX-2 inhibitor, prior to culturing on HA surfaces with or without the presence of SNAP. The levels of PGE2 were determined from the 3 day culture supernatants. The results showed that the production of PGE2 by HA-stimulated HOS cells was augmented by SNAP. Carboxy PTIO suppressed but L-NIO only partially inhibited the production of PGE2 by HA-stimulated HOS cells with or without the presence of exogenous NO. Pre-treatment of the cells with anti-human integrin alphaV antibody, indomethacin or nimesulide but not aspirin suppressed the production of PGE2 by HA-stimulated HOS cells with or without the presence of NO. Therefore, the results of the present study suggest that NO may up-regulate the production of PGE2 by augmenting the COX-2 pathway initiated by the binding between HOS cell-derived integrin alphaV and HA surface.
To compare morphological and positional variations of the hyoid bone in unoperated infants with cleft lip and palate (CL/P) with those in noncleft infants.
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.
Chondrosarcomas are malignant tumours of cartilaginous origin. They range from a well-differentiated growth resembling a benign cartilage tumour to a high-grade malignancy with aggressive local behaviour and the potential to metastasize. Only 5% to 10% of chondrosarcomas are known to occur in the head and neck region. A case of chondrosarcoma of the anterior region of the mandible is presented, along with a review of the relevant literature.
Hemangiomas are the most common congenital lesions in man and occur predominantly in the head and neck region. Massive hemangioma especially near vital organs or structures pose a challenge to surgeons. With the availability of expertise in embolization of feeding vessel of the hemangioma and reconstructive techniques we were able to manage successfully a complicated case of massive facial hemangioma.
The aims of this study are to determine the mutagenicity of a locally produced polyhydroxybutyrate (PHB) using Salmonella mutagenicity test and to find out if PHB altered the expression of p53 and c-myc proto-oncogenes and bcl-xl and bcl-xs anti-apoptotic genes in the human fibroblast cell line, MRC-5. Different concentrations of PHB were incubated with special genotypic variants of Salmonella strains (TA1535, TA1537, TA1538, TA98 and TA100) carrying mutations in several genes both with and without metabolic activation (S9) and the test was assessed based on the number of revertant colonies. The average number of revertant colonies per plate treated with PHB was less than double as compared to that of negative control. For the gene expression analyses, fibroblast cell lines were treated with PHB at different concentrations and incubated for 1, 12, 24 and 48 h separately. The total RNA was isolated and analysed for the expression of p53, c-myc, bcl-xl and bcl-xs genes. The PHB did not show over or under expression of the genes studied. The above tests indicate that the locally produced PHB is non-genotoxic and does not alter the expression of the proto-oncogenes and anti-apoptotic genes considered in this study.
The aim of the present study was to determine the effect of nitric oxide (NO) on the production of cyclic AMP (cAMP) by a human osteoblast cell line (HOS cells) stimulated with hydroxyapatite. Cells were cultured on the HA surfaces with or without the presence of NO donors (SNAP and NAP) for 3 days. The effect of adenylyl cyclase inhibitor (SQ22536), NO scavenger (carboxy PTIO) or endothelial nitric oxide synthase (eNOS) inhibitor (L-NIO), was assessed by adding these to the cultures of HA-stimulated HOS cells with or without the presence of SNAP. Furthermore, HOS cells were pre-treated with anti-human integrin alphaV antibody prior to culturing on HA surfaces with or without the presence of SNAP. The levels of cAMP and cGMP were determined from the 3-day culture supernatants. The results showed that the production of cAMP but not cGMP by HA-stimulated HOS cells was augmented by SNAP. SQ22536 and carboxy PTIO suppressed but L-NIO only partially inhibited the production of cAMP by HA-stimulated HOS cells with or without the presence of exogenous NO. Pre-treatment of the cells with anti-human integrin alphaV antibody suppressed the production of cAMP by HA-stimulated HOS cells with or without the presence of NO. Therefore, the results of the present study suggest that NO may up-regulate the production of cAMP, perhaps, by augmenting adenylyl cyclase activity initiated by the binding between HOS cell-derived integrin alphaV and HA surface.
This paper chronicled the development of a locally produced bone graft substitute based on calcium phosphate bioceramics called "GranuMaS--from concepts to clinics, and finally to its successful commercialization all within 5-year duration. It was a Prioritized Research (PR) collaborative project of 5 institutions namely SIRIM, ANM, USM, UKM and IIUM, funded by MOSTI to the amount of approximately RM2.5 millions under RM8. This paper also highlighted the requirements needed in terms of technical expertise/manpower, facilities and infrastructure, and government/institutional supports, as well as the challenge faced in developing and commercializing such product.
BACKGROUND: Numerous methods of age estimation have been proposed. The Demirjian method is the most frequently used, which was first applied in a French Canadian population in 1973. The Willems method is a modification of the above and was applied in a Belgian population in 2002.
OBJECTIVES: The objectives of this study were to test the applicability of the two methods, namely Demirjian and Willems, for age estimation in a Malay population, and to find the correlation between body mass index and the difference between the dental age and the chronological age.
MATERIALS AND METHODS: A cross-sectional study involving 214 boys and 214 girls, selected by a simple stratified random sampling method was carried out. The orthopantomograph was used to score the seven left mandibular teeth, and the calculated maturity score was used to obtain the Demirjian dental age. Willems dental age was estimated using the tables proposed in the Willems method. Results. The Demirjian method overestimated the age by 0.75 and 0.61 years, while the Willems method overestimated the age by 0.55 and 0.41 years among boys and girls, respectively. In boys, the body mass index was significantly correlated to the difference in age using the Willems method.
CONCLUSION: Further modification of either method is indicated for dental age estimation among the Malay population.