Metalloproteinases 2 and 9 Immunoexpression in Periapical Lesions from Primary Endodontic Infection: Possible Relationship with the Histopathological Diagnosis and the Presence of Pain

IntroductionThe aim of this study was to evaluate the possible associations among the histopathological diagnosis, the inflammatory infiltrate profile, the presence of pain, and the immunoexpression of matrix metalloproteinases MMP-2 and MMP-9 in periapical lesions from primary endodontic infection.MethodsFifty-one primary periapical lesions obtained from extracted teeth were selected for this study. Patients were previously evaluated for the presence of pain and sinus tract related to the tooth to be extracted. Tissues were processed for microscopic examination and MMP-2 and MMP-9 immunoexpression. Microscopically, samples were classified as periapical granulomas or periapical cysts and the inflammatory infiltrate as chronic or mixed. The percentage of immunopositive cells for MMP-2 and MMP-9 of each case was performed based on 10 consecutive microscopic fields. The Student t or chi-square tests were used in the statistical analysis.ResultsOf the total, 28 cases were classified as periapical granulomas (54.90%) and 23 cases as periapical cysts (45.10%). Seventeen patients (33.33%) reported pain associated with the extracted tooth, with 12 cases of periapical granulomas (70.58%) and 5 cases of periapical cysts (29.42%). All cases showed immunopositivity for MMP-2 and MMP-9 in a high percentage of cells, mainly in the cytoplasm of the leukocytes. MMP-2 was expressed more in periapical granulomas than periapical cysts (P < .05) and in symptomatic cases (P < .05).ConclusionsAccording to the results, we may conclude that MMP-2 and MMP-9 are highly expressed in periapical lesions from a primary endodontic infection. Moreover, we may suggest MMP-2 is expressed more in periapical granuloma and in cases associated with pain.