RESUMO
INTRODUCTION: Acute and chronic apical abscesses are 2 dramatic ways that periradicular tissues may react to pulpal infection and necrosis. Although both of these clinical states are the response to pulpal infection, their clinical manifestations are significantly different. It is not clear why the body responds to root canal infection in one way or another. The objective of this study was to evaluate the size and pattern of bone loss in patients with acute apical abscess (AAA) and chronic apical abscess (CAA) using cone-beam computed tomographic images. METHODS: Twenty-three cone-beam computed tomographic images of cases with AAA and 25 cases with CAA were selected and evaluated. The presence and location of fenestration and the volume and pattern of the periradicular lesions were recorded and compared between the 2 groups using the Fisher exact and Mann-Whitney U tests. RESULTS: One hundred percent of cases with CAA had cortical fenestration, but only 47% of cases with AAA had cortical fenestration (P < .05). The median volume of the lesions was 233 mm3 in the CAA group and 109 mm3 in the AAA group (P > .05). CAA cases, in comparison with the AAA group, had a relatively larger cortical disruptions. CONCLUSIONS: Cortical fenestration is fundamental for the development of CAA. However, periradicular lesions without evident cortical fenestration can still cause AAA and fascial space involvement.