Browsing by Author "Osman, Yusuf"

Now showing 1 - 4 of 4
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    Aesthetic reconstruction with fiber-reinforced polymerceramic crowns: a case study
    (South African Dental Association, 2005) Osman, Yusuf; Rahbeeni, Ricky
    Adhesive dentistry is rapidly evolving. Two main incentives drive this evolution - advances made in adhesive techniques combined with a demand for aesthetic restorations by patients .Patients want their teeth restored not only anatomically, but also aesthetically. Adhesive materials and indirect restorations currently available allow for these needs to be met in most instances using the concept of "minimally invasive" and "minimal intervention" dentistry.
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    The association of mercury from dental amalgam with urinary selenium
    (University of the Western Cape, 2017) Aljabo, Rukaia Emhemed; Oelofse, Andre; Osman, Yusuf
    Background: Dental amalgam has been the traditional material for filling cavities in teeth. Mercury (Hg) is a component of dental amalgam, from where it is continuously released and deposited in different tissues, mostly in the brain and the kidneys. Selenium is an important essential element in the human body. Mercury exposure from dental amalgam fillings associated with reduced the levels of selenium. Aims and objectives: The aims of the current study were to investigate the leaching of mercury from dental amalgam fillings and also to investigate the relationship between the leached mercury from dental amalgam fillings and selenium concentrations in the bloodstream. The objective was to determine the mercury from dental amalgam fillings and urinary selenium levels. Methods: Samples were collected from patients attending Tygerberg Oral Health Centre, Cape Town (South Africa). 107 patients who had 1-12 dental amalgam fillings provided the samples of urine, buccal swabs and did the chewing gum test. The samples were analysed by using inductively coupled plasma-mass spectrometry. The data were analysed by IBM (p<0.05) test with an SPSS computer software package version 24. The study involved analyses of samples of urine (n=107), chewing gum and buccal swabs (n= 102). Results: The median urinary concentrations of mercury and selenium in female and male samples were 0.40 μg/L, 0.60 μg/L Hg and 26.29 μg/L, 29.32 μg/L Se respectively. While the median Hg concentrations in chewing gum test and buccal swabs samples in female and male were 2.04 mg/g, 1.89 mg/g Hg and 0.16 μg/L, 0.09 μg/L respectively. Conclusion: The excretion of urinary selenium concentration was influenced by concentration of mercury in urine and age of participants but not affected by concentrations of mercury in buccal swabs, chewing gum and gender of participants.
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    Mercury leaching from dental amalgam fillings and its association with urinary zinc
    (University of the Western Cape, 2019) Zanager, Afaf Mohamed; Oelofse, Andre; Osman, Yusuf
    Mercury (Hg) is an example of a toxic metal that is not essential for nutrition. It exists in organic and inorganic forms in seafood and vapour from dental amalgam fillings respectively. Elemental mercury (Hg0) from dental amalgam was the focus of this study. Dental amalgam is one of the most commonly used dental filling materials and has been used for over 150 years. It is composed of Hg0 (approximately 50%) combined with other metals such as copper and zinc (Zn). These fillings give off Hg0 vapour throughout their existence, and is further enhanced by activities such as chewing, grinding of teeth and drinking hot liquids. Mercury consumption can lead to Zn loss or deficiency, and is reported to displace Zn and copper. Several European nations have outlawed the use of amalgam as a restorative material due to controversies regarding its safety in children, women of childbearing age and individuals with renal disease. Moreover, various studies have reported correlations between the number of amalgam fillings and Hg concentration in blood plasma, urine, faeces, saliva and different organs. Blood, urine, and hair mercury levels are used to predict possible health effects that may be caused by the different forms of Hg. Urine Hg is used to test exposure to metallic Hg0 vapour and inorganic Hg forms. This study aimed to evaluate the effects of Hg0 from dental amalgam restorations on the status of Zn in the urine. This was done by determining the concentrations of Hg0 in urine, buccal cells and the oral cavity, and its relationship with urinary Zn concentrations in the same individuals. Samples of urine, buccal tissues, chewing gum and completed questionnaires were collected from the participants (women and men) at the dental clinics in Tygerberg Hospital (TBH), Cape Town. Samples were analyzed using inductively coupled plasma mass spectrometer (ICP-MS). Findings from this study show that there was a correlation between levels of urinary Hg0 and urinary Zn (p=0.02). However, urinary Hg0 did not predict the amount of urinary Zn. Also, no relationship was found between levels of Hg0 in buccal swab or the chew test samples and urinary Zn level. There was a significant difference between females and males in the level of urinary Zn, men had higher levels of Zn excreted in the urine than females (p=0.05). However, there was no significant difference in the level of urinary Hg0 between males and females. The number of fillings (4-7) and age of fillings were significantly associated with urinary Hg0 level (p˂0.05), while smoking ˃15 cigarettes/day increased the level of Hg0 in buccal swab samples (p=0.002). We were not able to demonstrate a causal effect of Hg0 leaching on urinary zinc levels.
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    The strength of provisional crown and fixed partial denture (bridge ) materials
    (University of Western Cape, 1988) Osman, Yusuf; Owen, C. P
    Provisional crown and fixed partial denture (bridge) materials are often referred to as "temporary" materials. The Oxford Dictionary defines temporary as "lasting, or meant to last only for a time; not permanent". Yet for crown and fixed partial denture restorations a provisional restoration is crucial to the final restoration. It is, or should be, a preview of the final prosthesis.