Saudi Cultural Missions Theses & Dissertations
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Item Restricted Decellularized tissue-derived scaffolds in bone tissue engineering(King’s College London, 2021-08) Alokla, Mohammad; Deb, SanjuktaBone tissue engineering has received significant attention due to its enormous potential in treating critical-sized bone defects and related diseases. The shortage of suitable autograft and allograft materials for augmenting bone healing has accelerated research in developing clinically viable tissue engineered bone constructs. Optimal scaffold for bone tissue engineering should be osteoconductive, osteoinductive, biodegradable, sterilizable, provide adequate mechanical support bioactivity and biocompatible, hence traditional materials such as polymers, polymer-composites, ceramics and metals have been widely researched as scaffolds, however clinical applications have been limited due to different limitations. A three-dimensional scaffold that is able to replicate the in vivo microenvironment is essential for bone tissue engineering and the use of decellularized scaffolds is an approach that is generating interest especially the role of cellulose from plant source. This review discusses the anatomy of bone with a focus on bone physiology, bone defects and existing treatments, bone tissue engineering and then summarizes the status of the use of decellularized plant and animal tissues, different types of decellularization processes and clinical challenges.14 0Item Restricted Investigation into the effect of a custom-made jig to enhance guide plane preparation and partial denture framework retention(Queen Mary University of London, 2024-07) Alokla, Mohammad; Patel, Mangala; Friel, TimTooth loss is a common disease and removable partial denture (RPD) is an option to replace missing teeth. One of the major issues of RPDs is reduced retention. Guide plates are RPD components that restrict the path of insertion and improve frictional retention. Dental practitioners have to prepare parallel guide planes on abutment teeth which is difficult to achieve clinically. The invention of a custom cutting guide using computer-aided design and computer-aided manufacture (CAD-CAM) technology by 3Shape TRIOS® software may enhance the accuracy of preparing parallel guide planes, thus improving the RPD retention. The aim of this project was to create a cutting guide using a novel process in CAD-CAM technology and investigate the effect on guide plane preparation and RPD retention. In this project, a bounded saddle master model was selected and duplicated into 40 printed resin models. Four abutment teeth were included in the tests. The upper right second molar (UR7), the upper right first premolar (UR4), the upper left second molar (UL7), the upper left first premolar (UL4) were utilized. The duplicated models were divided into two groups. In the first group (A), 20 cobalt-chromium (Co-Cr) frameworks were fabricated without guide plane preparation for 20 printed models, and the frameworks retention were assessed. In the second group (B), 20 Co-Cr frameworks were designed and fabricated based on prepared guide planes on 20 models. The guide plane preparations of group B were performed using a custom-made jig. The model base was used as a standardised reference for designing the jig and assessing the accuracy of guide plane preparations. The retention of group B frameworks were measured and the accuracy of guide plane preparations were evaluated. The results showed that the average of maximum load for testing retention of RPD frameworks was 1.887 ± 2.779 N (N=Newtons) in group A unprepared models and 0.350 ± 0.575 N in group B prepared models. The accuracy assessment of prepared guide planes in group B showed that the average angle between the model base and UR7 guide plane was 102⁰ ± 1.21 degrees. The average angle between the model base and UR4 was 93⁰ ± 1.86 degrees. The average angle between the model base and UL4 was 92⁰ ± 2.03 degrees. The average angle between the model base and UL7 was 103⁰ ± 2.39 degrees. Also, the measurement of parallelism between opposing guide planes on the right and left bounded saddles of prepared guide planes in group B showed that the average angle on the right side between UR7 and UR4 was 15⁰ ± 2.47 degrees, and the average angle on the left side between UL7 and UL4 was 15⁰ ± 3.36 degrees. Lastly after guide plane preparation in group B, the average of maximum depth tooth reduction on UR7 0.38 ± 0.09 mm, UR4 0.36 ± 0.09 mm, UL4 0.43 ± 0.14 mm, and UL7 0.42 ± 0.11 mm. In conclusion, the resin custom-made Jig that was designed using 3Shape software resulted in non-parallel guide planes and divergent guide plane angle which reduced retention of Co-Cr frameworks in group B prepared models compared to group A non-prepared models. Therefore, the chosen design of the jig negatively influenced the accuracy of guide plane preparation and framework retention. 14 0