The purpose of this RFA is to encourage the use of genomic and proteomic approaches and imaging techniques to clarify the molecular events involved in: 1) acute orofacial pain, 2) the transition from unrelieved acute pain to chronic pain (i.e. neuroplasticity), 3) neuronal hyperexcitability as manifested by hyperalgesia and allodynia, and 4) chronic orofacial pain disorders of an inflammatory and neuropathic origin. This improved understanding could lead to new therapeutic interventions to effectively treat chronic pain conditions. Collaborative projects involving interdisciplinary teams of investigators are strongly encouraged. This Request for Applications contributes to the goals of the NIH Pain Consortium, which is co-chaired by NIDCR, NINDS, and the National Institute of Nursing Research (NINR).