Magister Chirurgiae Dentium - MChD (Prosthodontics)

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    An investigation into the compatibility of some irreversible hydrorocolloid impression materials and dental gypsum products
    (University of the Western Cape, 1983) Owen, Christopher Peter; Wildlng, R J C
    This was based on a similar procedure described by Morrow et al (1971) but differed ln several respects. By photographing the gypsum casts through a stereomicroscope at constant signification and using a constant light source, It was possible to produce a consistent, photomicrograph. The gypsum casts were photographed with black-and-white flu, and high-contrast prints obtained of the best-reproduced section of the 01050 mm line. These prints were then subjected to an evaluation procedure using four evaluators who gave a score to the quality of reproduction of the line on a rating scale of I to 4. A11 prints were scored three times by each evaluator, and the sums of these three scores were subjected to statistical analysis. The statistical analysis showed this procedure to be consistent, and that it could be expected to be repeatable. On the basis of this analysis, it was found that one alginate was clearly superior to all others, and that it was possibe to distinguish a further group of combinations within the group that reproduced the 0r050 mm line. Some of the alginate materials were treated with fixing solutions of varying concentrations of potassium sulphate and alum. The results obtained were varied, sometimes producing marked improvement, sometimes deterioration ln the surface quality of the subsequent gypsum cases. None of the treated materials could be improved to the extent of equating then with the best of the naturally compatible combinations
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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.
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    The fracture resistance of structurally compromised roots using different post systems
    (University of the Western Cape, 2002) Solomon, Charlene S; Osman, Y.I
    The structurally compromised root presents a great challenge to the restorative dentist. The amount of tooth structure that remains after endodontic therapy and post preparation is of prime importance and the strength of an endodontically treated tooth is directly related to the amount of residual dentine. Post and cores are often required with pulpless teeth to provide retention and resistance form for the final restoration. Aim: The purpose of this in vitro study is to investigate the fracture resistance of structurally compromised teeth using four dynamically different post and core systems in the rehabilitation process. Method: After the crowns were removed one specimens were then randomly divided into four groups of 25 teeth each as follow: Group A: morphologic cast post and core; Group B: resin reinforced glass-fibre post and composite core; Group C: resin reinforced carbon fibre post with composite core and Group D: resin reinforced prefabricated parallelsided titanium post and composite core. All specimens were subjected to an increasing palatal force until fracture occurred. Results: Results showed cast post and cores to have higher fracture loads that the resin reinforced groups (p< 0). The difference in fracture resistance between the three reinforced groups was found not to be significant (p > 0). Conclusions: Significantly higher fracture thresholds were obtained in the cast post-and-core group. The reinforced group (with composite cores) showed failure of the post-core interface before the fracture of the tooth occurred. This failure occurred in response to acceptable high loads. The Luminex@ light transmitting posts can help strengthen weakened, endodontically treated teeth by the combined bonding action of dentine bonding agents and composite resin restorative material.
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    The efficacy of rotary and manual instruments in root canal debridement.
    (University of the Western Cape, 2009) Madlabane, Duduzile; Osman, Y.I.
    It has been shown thot the use of both manual and rotary instruments result in the formation of o smear layer and debris during root canal treatment. The amount thot is formed depends on the type of instrumentation used as well as the force applied. Aim: The purposes of this study were. To use the scanning electron microscope to compare the cleanliness of the root canal walls following rotary and manual debridement methods 2. To assess the transportation of the apical port of the root canal orifice when using different instrumentation techniques. Materials and Methods: Endodontic treatment was performed on extracted maxillary central incisors following exportation and debridement using the Protaper@ nickel titanium files and K-files. The teeth were randomly divided into three groups. Endodontic therapy performed simulated the clinical procedures, in which the teeth were extirpated using o barbed broach to remove the necrotic pulp. Pre-operative periodical radiographs were used to determine the working length. Root canals were debrided using the two filing methods, with copious irrigation using Sodium hypochlorite solution in o disposable syringe with o 27 gauge needle. A follow up radiograph with o master apicol file in position was used to verify complete debridement in the apicol third of the canal. The teeth were then sectioned vertically using o diamond bur to create an initial groove and then split apart using q flat plastic instrument to separate the sections and to avoid contamination of the sections. These sectioned portions were then studied under o scanning electron microscope. The smear layer as well as the amount of debris was evaluated.
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    An in-vitro comparative micro-computed tomographic evaluation of three obturation systems
    (University of the Western Cape, 2017) Kabini, S.N.; Moodley, D.; Patel, N.; Parker, M.E.
    Gaps or voids between walls of root canal and obturation material may lead to re-infection of the obturated root canal. Therefore, adaptation of the obturation material to dentine walls is essential for the success of root canal treatment.
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    An in-vitro study of the physical properties of core build-up materials
    (University of the Western Cape, 2017) Asia, Winifred; Patel, N.; Moodley, D.
    The aim of this study was to evaluate and compare the physical properties of two core build-up materials (ParaCore and CoreXflow) and compare this to conventional composite material (Filtek Supreme Plus and SDR Flow) used as core build-up material.
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    A comparative study between thermoplastic and conventional removable partial denture designs
    (University of the Western Cape, 2019) Farao, Warren Emile; Geerts, Greta
    Three dental laboratories in the Cape Town Metropole that were known to fabricate “flexible” or NMCDs for dental practices were identified and were invited to participate in the study. Their participation consisted of emailing photographs of completed metal-frame, acrylic and flexible RPDs and their casts prior to sending them to the practices for delivery to patients. Specimens were collected until a total of 20 metal-frame, 20 acrylic resin and 20 flexible RPDs were received. A design was drawn for each submitted RPD. For each RPD, an “ideal” design was drawn, using the image of the cast. This was done by two observers, who are experienced members of staff in the Department of Restorative Dentistry (Prosthetics), independently. The designs from both observers were later compared for similarity. Where differences existed in the designs, these were resolved by means of discussion until agreement was reached. Each ideal design served as the control for each clinical design.The number of rests, their configuration, the type of support, number of clasps, the presence of indirect retention, cross-arch stabilization, the number of teeth whose periodontal tissues were covered by design components for each design among the different denture type groups, and corresponding control designs were identified and reported. The ratios of teeth replaced/teeth covered per denture type groups and per classification, and corresponding control designs were compared.