Project Abstract The MOLAR study uses a hybrid effectiveness-implementation study to perform a randomized controlled trial of an intervention to reduce unmet oral health and social needs in the ED, while collecting information to inform subsequent implementation strategies. In this mixed-methods supplement, we build on the work of the MOLAR study to understand how geographically-proximate resources and navigational assistance moderate adverse social determinants of health (aSDoH) and oral health outcomes, and what barriers remain. In particular, we intend to explore facilitators and barriers at the patient level (Aim 1), system level (Aim 2), and combine this knowledge with quantitative results to identify the conditions that contribute to successful ED-based oral health linkage (Aim 3). This work would provide key generalizable insights for how to optimize ED based aSDoH and oral health interventions. In doing so, we fulfill two of the primary goals of the NIDCR Strategic Plan: (1) Enabling “precise and personalized oral health care” by developing a model to identify patients at risk in the ED and facilitating their connection to local, accessible, community oral health care; and (2) Using “multidisciplinary research approaches to overcome disparities and inequalities” by using the ED to enroll patients who do not otherwise have access to oral health care and ensure that they are connected to appropriate community resources for their social needs and oral health care. By doing so, we understand and address the potential drivers of poor oral health and the challenges around accessibility of oral health care. Our long-term goal is to reduce the burden of untreated oral disease in vulnerable populations by integrating screening and referral for oral health and aSDoH into ED care.