QUANITATION OF PULP/PERIAPICAL INFLAMMATION USING PET MARKER 11C-MK-4232 CALCITONIN-GENE-RELATED PEPTIDE RECEPTOR: A PILOT STUDY

Background This study aimed to establish a quantitative method for measuring dental pulp disease in vivo. Current clinical examinations of the dental pulp use thermal (hot/cold), (percussive/palpatory), and electric pulp testing to evaluate tooth vitality. These tests offer some utility, but the results are extremely variable and subjective. Standard radiography has also been used, but it lacks diagnostic sensitivity until the disease process is advanced. Objective The study combines 2 novel areas of contemporary medical research: positron emission tomography (PET) and immune pathway modulation to develop a noninvasive diagnostic tool that can be used for the detection and localization of dental pulp disease. The calcitonin-gene-related peptide (CGRP), a neuropeptide released when the peripheral nervous system, regulates the immune system by activating the inflammatory process. We used a specific PET-tracer, [11C]MK-4232, a CGRP receptor marker to locate and quantify CGRP released and bound to the receptor at specific times in response to the progression of induced pulp disease. Materials and Methods This study used [11C]-CGRP-R produced in the Loma Linda University radiochemistry laboratory to quantitate the uptake of the PET tracer in diseased teeth of 6 ferrets after pulpal irritation of canines to induce pulp disease. Conjoint histopathologic studies were performed to quantitate cellular response to inflammation. These values were then compared with the PET tracer uptake. Preliminary Results Previous studies using the [11C]-CGRP-R marker in mini-pigs had reported promising results quantifying the CGRP pathway. Future Directions It is anticipated that investigations of the PET tracer [11C]MK-4232 (CGRP-R) to localize and monitor pulp disease will prove to be a dependable, objective, quantifiable, and repeatable diagnostic tool.