SACM - United States of America

Permanent URI for this collectionhttps://drepo.sdl.edu.sa/handle/20.500.14154/9668

Browse

Now showing 1 - 2 of 2

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, Frederico
The 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 0
Restricted
The Etiology of Peri-implantitis: Microbiological Profile Within and Around Dental Implants and the Associated Human Immune Response
(2023) Kensara, Anmar; Masri, Radi
Objectives: To characterize the microbiome composition within and around dental implants of peri-implantitis subjects and within and around healthy implants using 16S rRNA gene sequencing, and to profile salivary inflammatory mediators associated with peri-implantitis compared to healthy controls from the same subjects. Methods: A total of 24 subjects (peri-implantitis n=14, healthy n=10) were enrolled in the study. From the 24 subjects, 24 endosseous implants from affected (peri-implantitis) and 14 healthy controls were included in this cross-sectional study. Samples for microbiological analysis were obtained from the internal surfaces of dental implants and peri-implant sulcus using sterile paper points. DNA was extracted and 16S rRNA gene was amplified using universal primers targeting the V3-V4 regions. Amplicons were sequenced using Illumina MiSeq platform. Alpha and beta diversity, core microbiome, and taxa differential abundance were assessed. Saliva was collected from the same subjects for immunology-based assays. Salivary inflammatory mediators in peri-implantitis and healthy implant subjects were profiled using antibody arrays. Results: A significant increase in microbial diversity was observed in the internal implant surface of healthy implants compared with the internal surfaces of peri-implantitis (Shannon P= 0.02), and no significant differences in microbial diversity between healthy implants sulci and peri-implantitis pockets (Shannon P= 0.82). Bacterial community structure was significantly different within implant in both healthy and peri-implantitis groups (P= 0.012) but not significantly different around implants in both healthy and peri-implantitis (P= 0.18). Enterococci is the predominant bacteria within peri-implantitis (LD >2.0, P< 0.05). Abundant species in peri-implantitis were C. leadbetteri, T. maltophilum, Peptostreptococcus, Neisseria, P. gingivalis, and P. endodontali, L. lactis and F. alocis (P < 0.05). Gram-positive bacteria such as S. salivaris, P. melaninogenica, L. wadei, and Actinomyces spp were more abundant in the peri-implant healthy sulcus. Around 48% of detected bacteria were cultivable in general media. In addition, out of 105 analytes examined in saliva, we found that 29 mediators were upregulated in subjects with peri-implantitis (P < 0.001). Conclusions: Our results indicate that microbial colonization of the internal implant surface may act as a major contributor to the etiology of peri-implant disease. Multiple inflammatory mediators were significantly elevated in the saliva of peri-implantitis patients compared to healthy implant patients.
30 0