No description available.

No description available.

No description available.

No description available.

No description available.

The purpose of this investigation was to observe the sequential ultrastructural changes in tumor implants of a well established tumor line in isologous mice.

Purpose It is known that distortions can occur during impression making and the pouring of casts, and that this distortion may produce inaccuracies of subsequent castings, especially long span castings for implant superstructures. The purpose of this study was to compare the ability of different impression materials to reproduce the positions of 5 implant analogues on a master model, in terms of their accuracy and the accuracy of a resultant cast, relative to the master model. Method The master model was a stainless steel model with 5 implant analogues. The impression materials used were impression plaster (Plastogum), a polyether (Impregum Penta), and two polyvinyl siloxane materials (Aquasil Monophase and Aquasil putty with light body wash). Five impressions were made with each impression material and cast in Satin stone under controlled conditions. The positions of the implants on the master model, the impression copings, and the implant analogues in the subsequent cast were measured using a co-ordinate measuring machine which measures within 4μm of accuracy. Results Statistical analysis using a one factor t-test indicated that distortion occurred in all the impression materials, but inconsistently. Aquasil Monophase reproduced the master model most accurately. Although there was no significant distortion between the Aquasil monophase impressions and the master model or between the impressions and their casts, there were distortions between the master model and the master cast, which highlighted the cumulative effects of the distortions. Impregum’s performance proved to be the most reliable in terms of predictability. Plastogum displayed cumulative distortion and with Aquasil putty with light body, these impression materials had the least reliability. Conclusions Some of the distortions observed are of clinical significance and likely to contribute to a lack of passive fit of any superstructure. The unpredictability of such distortions may mean that the future of accurate impressions and superstructures may lie in the digital world.

Abstract Background: It is well documented in the international literature that when implants have been placed with primary stability in the edentulous mandible, immediate or early loading of the implants can be highly successful. Success rates of between 85-98% have been reported.1 However, no evidence has been published on the success rates of implants placed post-extraction with immediate or early loading in South Africa. Objectives: The investigation reported in this dissertation was undertaken to compare the success rates of early loaded implants placed in a) Edentulous mandibles and maxillae (delayed placement), b) “Fresh” extraction sockets with prior alveolectomies within the mandible/maxilla (immediate placement). Methods: In a private maxillo-facial surgical practice and a private prosthodontic practice, the number of patients who had received implants, number of implants per patient, type of implant placed (Southern or Nobel Biocare), total number of implants, site of implant placement and type of prosthesis placed were recorded. The success rates were evaluated using the following criteria3: A) Absence of clinically detectable implant mobility B) Absence of soft tissue infections, persistent pain, paraesthesia, or discomfortimplants, site of implant placement and type of prosthesis placed were recorded. The success rates were evaluated using the following criteria3: A) Absence of clinically detectable implant mobility B) Absence of soft tissue infections, persistent pain, paraesthesia, or discomfortimplants, site of implant placement and type of prosthesis placed were recorded. The success rates were evaluated using the following criteria3: A) Absence of clinically detectable implant mobility B) Absence of soft tissue infections, persistent pain, paraesthesia, or discomfortC) Radiographic evaluation of bone loss D) Period of follow-up, that is loading period Results: The records of 22 patients who had had 121 implants placed with early loading over a 3 - 45 month period were studied. Of the 121 implants, 107 implants showed no bone loss, and 14 showed bone loss. Furthermore, 4 implants were lost in 2 patients, both patients having had implants placed in edentulous jaws. No clinical complications were seen in any patients. Conclusions: Implants with early loading placed in edentulous jaws showed a 94.1% survival rate during the study period, while those placed into fresh and immediately post-extraction sockets showed a 100% survival rate. The failure rate was too low for further analysis.

PhD, Faculty of Health Sciences, University of the Witwatersrand, 2009

The decision regarding cochlear implantation is complex and involves the consideration of a multitude of factors that will influence the future of a hearing impaired child. Parents are often faced with the task of making this decision urgently during a period when they dealing with the diagnosis of a hearing loss. To date, there is sparse literature available on parental readiness for cochlear implantation. An understanding of parental experiences during the decision making process will help professionals involved in the cochlear implant teams to help parents through this difficult decision making time and hence have significant clinical implications for future practice. This is particularly relevant in South Africa where there is very little literature to guide both parents and professionals with regard to decision making. The objective of this study was to determine parental descriptions of their experiences with regard to the decision of cochlear implantation for their young children with hearing loss as well as the factors that needed to be considered by the parents for the child when deciding on a cochlear implant. Semi structured interviews were conducted with 13 parents at a Learning Facility in South Africa. The results revealed that the decision for cochlear implantation was based on two critical factors which were the sense of urgency and the future of the child. Other considerations such as the financial consideration, surgical risk, aesthetics, communicative outcomes, family consensus, and parental readiness were identified. The power of professionals during this time when decisions are being made in the context of ignorance and within an oral environment was revealed. This finding raised the question of the ethical and moral practice of professionals involved in cochlear implantation.