The present in vitro evaluation indicated that the value added hydroxyapatite (HA) was more toxic than pure HA but the toxicity of value added HA was slight compared to the positive control. In this testing, the conclusion can be made that value added HA is less biocompatible than commercialized pure HA. This toxicity may be caused by both the particle size and degradation (leaching). Further studies should be carried out to determine whether there is particle size effect or leaching effect when using powder as compared to the block materials. The in vivo evaluation should be done to assess the reaction to this value added HA as compared to the pure HA.
Mutagenicity of CORAGRAF (natural coral) and REKAGRAF (hydroxyapatite) was tested in Ames test with and without an external metabolic activation system (S9). The test revealed no mutagenic activity of both locally produced osseous substitutes.
This study was designed to evaluate the ability of natural coral implant to provide an environment for marrow cells to differentiate into osteoblasts and function suitable for mineralized tissue formation. DNA content, alkaline phosptatase (ALP) activity, calcium (Ca) content and mineralized nodules, were measured at day 3, day 7 and day 14, in rat bone marrow stromal cells cultured with coral discs glass discs, while cells alone and coral disc alone were cultured as control. DNA content, ALP activity, Ca content measurements showed no difference between coral, glass and cells groups at 3 day which were higher than control (coral disc alone), but there were higher measurement at day 7 and 14 in the cell cultured on coral than on glass discs, control cells and control coral discs. Mineralized nodules formation (both in area and number) was more predominant on the coral surface than in control groups. These results showed that natural coral implant provided excellent and favorable situation for marrow cell to differentiate to osteoblasts, lead to large amount of mineralized tissue formation on coral surface. This in vitro result could explain the rapid bone bonding of coral in vivo.
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.
Nasal obstruction is a subjective complaint in patients with nasal disease. The ability to quantitate the nasal ventilation dysfunction would be useful for making the appropriate choice of nasal disease management. This cross-sectional study comprised of 200 adult subjects. They underwent assessment of relevant symptoms, nasal examination and investigations before undergoing active anterior rhinomanometry (AAR) assessment. A group of 88 normal subjects and 112 patients with nasal disease were included. The mean total nasal air resistance (NAR) was significantly higher in patients with nasal disease (0.33 Pa/cm(3)/s) as compared to normal subjects (0.24 Pa/cm(3)/s). There was no significant difference in total NAR between patients with symptoms of nasal obstruction and those without the symptoms (p = 0.42). It is concluded that AAR is a sensitive but not a specific tool for the detection of abnormalities in NAR and it failed to relate to the symptom of nasal obstruction.
The differences in facial anatomical structures of the major ethnic groups, may also be reflected in nasal resistance. Active anterior rhinomanometry (AAR) is the recommended technique for the objective assessment of nasal airway resistance (NAR). This study comprised of 85 adult Malay subjects. All the subjects had to undergo a primary assessment of relevant symptoms of nasal disease and nasal examination before undergoing AAR assessment. The mean value of total nasal airway resistance (NAR) was 0.19 Pa/cm(3)/s (ranged from 0.09 to 0.55 Pa/cm(3)/s) at 75 Pa pressure point and 0.24 Pa/cm(3)/s (ranged from 0.12 to 0.52 Pa/cm(3)/s) at 150 Pa pressure point. The mean unilateral NAR was 0.46 Pa/cm(3)/s at a reference pressure of 75 Pa and 0.51 Pa/cm(3)/s at a reference pressure of 150 Pa. In this study we presented normal values for NAR in healthy Malay adult subjects. AAR proves to be a valuable clinical method for recording and quantitating nasal resistance.
Hyalinizing clear cell carcinoma is a low-grade neoplasm of the minor salivary gland composed exclusively of epithelial cells and not myoepithelial cells. It predominantly affects the oral cavity of adult females. It is microscopically characterized by hyalinizing stroma and clear cells, which are typically positive for cytokeratin markers and negative for S 100 and smooth muscle actin (SMA). Cystic degeneration can also be present. Pathologists should be aware of this new entity so as not to misdiagnose otherwise. To our knowledge, this is the first case report of its kind from Malaysia.