Saudi Cultural Missions Theses & Dissertations
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Item Restricted Clinical Investigation of the Impact of Endodontic Disinfection on the Bacteriome of Root Canal Infection Using Next-Generation Sequencing on the Illumina MiSeq Platform(University of Maryland, Baltimore, 2024-07-01) Alquria, Theeb; Martinho, FredericoThe primary cause of root canal infection is bacteria and their by-products, making disinfection of the root canal system a key goal in endodontic therapy. However, the complex anatomy of root canal systems, particularly the isthmus and its ramifications, poses challenges for effective disinfection. Currently, no disinfection protocol can eliminate all bacterial contents from root canal infections, driving the ongoing search for an optimal disinfection approach. Recently, next-generation sequencing (NGS), particularly the Illumina MiSeq platform, has been widely explored in endodontic infections due to its low sequencing error rates, cost-effectiveness, and high-quality reads. Leveraging advanced sequencing techniques to reveal the bacteriome of root canal infections and assess the impact of current disinfection methods could enable the development of more targeted and effective disinfection protocols. This dissertation presents an interventional clinical study aiming to investigate the diversity and composition of the bacteriome in primary endodontic infection (PEI) with apical periodontitis (AP) and evaluate the impact of root canal disinfection on the endodontic bacteriome using NGS on the Illumina MiSeq Platform. First, we characterized the bacteriome in PEI with AP, identified core and rare bacteriome species, and analyzed community diversity metrics using the Illumina MiSeq platform. Our results showed that Bacteroidetes, Firmicutes, Synergistetes, Fusobacteria, and Actinobacteria were the most abundant bacterial phyla. We identified 113 genera and 215 species. Analysis revealed differences in abundant taxa among distinct age, gender, symptomatology, and lesion size groups. These findings suggest that the bacteriome in PEI with AP is complex and has high microbial heterogeneity among patients. Moreover, age, gender, symptomatology, and lesion size might play a role in the abundant taxa present in PEI with AP. Second, we determined quantitatively and qualitatively the impact of chemomechanical preparation (CMP) using 2.5% sodium hypochlorite (NaOCl) on the bacteriome found in PEI with AP using the Illumina MiSeq platform. Despite a significant decrease in bacterial abundance, our findings demonstrated a distinct community composition and increased alpha diversity after CMP. We observed differential enrichment of specific taxa, including Stenotrophomonas_unclassified, Enterococcus_unclassified, and Actinomyces_unclassified, suggesting lower effectiveness of CMP using 2.5% NaOCl against these taxa. Findings from this dissertation highlight the complexity and heterogeneity of the bacteriome in PEI with AP, emphasizing the influence of patient-related factors on microbial diversity. The research highlighted the limited effectiveness of current endodontic disinfection protocols, specifically the use of 2.5% NaOCl, in reducing bacterial abundance while revealing limitations against certain taxa. These insights provide a foundation for developing more targeted and effective disinfection strategies, potentially leading to improved outcomes in endodontic therapy.10 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 0Item Restricted The Effect of Simvastatin Scaffolds on human Periodontal Ligament Cells as a Potential Endodontic Regenerative Technique(2023) Almohimeed, Khawlah; Crawford, Aileen; Martin, NicolasRegenerative endodontic procedures have received considerable critical attention in the field of restorative and paediatric dentistry. Vital pulp is the best filling material a tooth can have, thus, maintaining pulp vitality is crucial in this respect. This is a preliminary study is to investigate the dose and timely release of 2% simvastatin from PLGA scaffolds as well as assess viability of human periodontal ligament cells (hPDL). The release of simvastatin in DMEM was much higher than PBS in the first 24 hours. Due to limitations in accessing the lab during Covid-19 Pandemic, spectrophotometer readings have only been obtained for a 96-hour incubation period on the Simvastatin PLGA scaffolds. HPDL showed viability after 96-hour incubation in 2% simvastatin PLGA scaffolds. the conclusion was that our newly fabricated 2% simvastatin PLGA scaffolds showed biocompatibility. Within the limitations of this study, we can conclude that using the newly fabricated 2% simvastatin PLGA scaffolds-maintained cell viability for 96 hours although it was lower than desired. Further research is needed in this respect especially that the present study contains preliminary data.26 0