Saudi Cultural Missions Theses & Dissertations
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Item Restricted Estimating the Impact of Co-localized Risk Variables on Peri-implant Diseases(University of Michigan, 2025) Albaqawi, Hoda; Purnima, KumarThis study hypothesizes that peri-implant diseases, including peri-implant mucositis and peri- implantitis, result from the combined influence of site-level anatomical factors and patient-level behavioral or systemic characteristics. Specifically, features such as inadequate gingival attachment, shallow vestibular depth, and poor interproximal hygiene access significantly increase the risk of disease onset and progression. Peri-implant diseased states are associated with distinct shifts in the peri-implant microbiome, marked by a transition from health-associated commensals to pathogenic, dysbiotic microbial communities. The aim of this study is to quantify the contribution of site-level and patient-level variables to peri-implant disease risk using multivariate modeling and machine learning techniques. Materials & Methods: In this cross-sectional analysis, 240 participants with single, non-splinted implants in function for at least one year were enrolled. Clinical and radiographic assessments categorized implants as healthy (n = 72), peri-implant mucositis (n = 135), or peri-implantitis (n = 33). Site-level factors (gingival attachment, keratinized mucosa, vestibular depth, plaque and inflammation indices, implant position) and patient-level variables (age, hygiene behavior) were analyzed using multinomial logistic regression and Random Forest classification. Linear Discriminant Analysis (LDA) of Bray-Curtis distances was applied to examine clustering based on combined variables. Results: Of the 240 implants analyzed, 47.1% were healthy, 40.4% had mucositis, and 12.5% had peri- implantitis. Multinomial logistic regression identified gingival attachment (GA <1 mm) and vestibular depth (VD <11 mm) as the strongest predictors of disease, with odds ratios of 4.2 and 7.8. The covaiate risk of the Interaction effects between shallow VD and inadequate keratinized mucosa (KM) significantly elevated mucositis risk. Implant adjacency without tooth support, shorter implant length, and posterior positioning were associated with peri-implantitis. The Modified Plaque Index (mPI) consistently predicted both disease states, with its impact intensified in sites with reduced GA, shallow VD, or limited KM. Random Forest models further highlighted age, interproximal hygiene access, and anatomical constraints as key features, achieving over 95% accuracy in disease classification. Conclusions: In conclusion, this study reinforces the multifactorial and interdependent nature of peri-implant disease risk. By integrating site-level and patient-level variables into a unified framework, we provide novel insights into how co-localized factors synergize to influence disease onset and progression. These findings advocate for early identification of site-level disease predictors, and preventive approach in implant therapy, highlighting the importance of individualized treatment planning and maintenance strategies for optimal long-term outcomes.8 0Item Restricted Polydopamine-ECM Coated Titanium to Promote Cementogenesis on Dental Implants(Harvard University, 2025) Alamri, Osamah; Traverso, GiovanniTitanium dental implants integrate directly with the surrounding bone, a phenomenon known as osseointegration. Unlike natural teeth, which are supported by periodontal ligaments (PDL), osseointegrated implants have weaker mechanical barriers against bacterial infiltration, heightened inflammation, reduced blood flow, and limited proprioception. Current methods to regenerate peri-implant ligaments involve costly, invasive, and time-intensive procedures. Polydopamine (PDA) is a biocompatible polymer known for its excellent adhesive properties. Periodontal ligament fibroblasts (PDLFs) play a pivotal role in periodontal tissue maintenance. Recent evidence suggests fibroblasts can induce a cementogenic phenotype by altering titanium surface topography and depositing cementum-like tissue. This study investigates PDA's efficacy in immobilizing ECM produced by PDLFs on titanium, hypothesizing enhanced cementogenesis on PDA-coated titanium surfaces. We assessed ECM immobilization efficiency, optimized decellularization protocols to retain ECM, and evaluated PDLF differentiation into a cementogenic phenotype. PDLFs cultured on PDA-coated titanium underwent decellularization after 10 days, followed by recellularization for 14 days. Cell interactions and gene expression were assessed using immunofluorescence microscopy, scanning electron microscopy (SEM), and RT-qPCR. Results demonstrated increased cell numbers on PDA-coated surfaces without affecting attachment or proliferation. Decellularization effectively removed cellular material, preserving key ECM proteins like Collagen I and CEMP-1. Gene expression analysis revealed significant upregulation of cementogenic markers (CP23, CAP, CEMP1, BSP) and downregulation of osteogenic markers (ALP, SOST), especially prominent on PDA-ECM surfaces. Our findings support that PDA-ECM-coated titanium surfaces promote cementogenic differentiation of PDLFs, potentially enabling peri-implant cementum-like tissue formation and periodontal ligament regeneration.17 0