Saudi Cultural Missions Theses & Dissertations
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Item 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 0Item Restricted The Role of Education on The Association Between Ethnicity and Tooth Loss(King's College London, 2024-08) Alfraih, Jood; Delgado Angulo, ElsaAbstract Aim: The study aimed to explore the association between tooth loss and ethnicity and to assess the mediating role of education in this relationship. Methods: A secondary analysis was conducted on cross-sectional data from adults aged 16 and over who participated in the Health Survey for England in 1999, 2000, 2001, 2002, and 2005. Logistic regression models were employed to examine the association between ethnicity and tooth loss, with the adjustment for sociodemographic variables. The role of education as a mediator in this relationship was also assessed. Results: The findings revealed significant ethnic differences in the prevalence of edentulism. Black Caribbean and White British participants exhibited the highest prevalence rates of edentulism, whereas Bangladeshi individuals had significantly lower odds of experiencing tooth loss. Education emerged as a critical determinant, with higher educational attainment associated with lower odds of edentulism. The mediation analysis highlighted that Black Caribbean individuals with no education had significantly higher odds of edentulism. Conclusion: The study underscores the complex interplay between ethnicity, education, and tooth loss. It highlights the need for public health interventions that target oral health education and improve access to care, particularly for ethnic minorities and lower socioeconomic groups.20 0Item Restricted Tooth Loss in Root Canal Treated Teeth: A Six-year Cross-sectional study(Saudi Digital Library, 2023) Alrumaih, Abdulaziz; Mannocci, FrancescoAim: The aim of this cross-sectional study was to assess and compare tooth loss rates in root canal treated and non-root canal treated teeth with different restorations, and to determine the influence of restoration type on tooth survival rates in a group of patients attending a large NHS hospital. Methodology: This study analysed 1030 orthopantomograms (OPGs) from 515 patients, including baseline (T0) and follow-up (T1) OPGs. Teeth were categorised as root canal treated (RCT) or non-root canal treated (non-RCT) and further subcategorised based on the radiographic restoration type. Comparisons were made between T1 and T0 to assess tooth loss rates. Variables recorded included tooth type, the number of teeth restored at T0, and the number of teeth crowned at T1. Statistical analyses used Wilcoxon's test, Spearman's correlation coefficient, and multi-level logistic regression with generalised estimation equations (GEE) at α = 0.05 significance level. Results: The overall tooth survival rate was 75.5%, with non-RCT teeth showing a higher survival rate of 78.11% compared to RCT teeth, which had a slightly lower survival rate of 64.73%. There was higher tooth loss in 3-s restorations (RCT and non-RCT) compared to 1-s and 2-s (P<0.05). RCT 3-s restorations had an 84% increased failure risk compared with non-root canal treated teeth (OR=1.84, P=0.003). Crowning rate for RCT teeth in the time interval taken into consideration was 4.8%. Gender had no significant association, except in non-RCT 2-s restorations where females had lower failure rates than males (P=0.025). Tooth position (anterior vs. posterior teeth) did not affect survival rates (P>0.05). Conclusion: This study reveals higher tooth loss rates in root canal treated teeth, especially with three surfaces restorations. Age is identified as a risk factor for failure, particularly in root canal treated teeth with crowns.11 0