Factors related to the effectiveness of decompression in unicystic ameloblastoma: a retrospective study.

The aim of this study was to identify factors that predict the outcome of decompression for unicystic ameloblastoma (UA) in the mandible. This was a single-center, retrospective, cross-sectional study of 40 patients with mandibular UA who underwent decompression as the primary treatment. Pre- and post-decompression panoramic radiographs were reviewed to evaluate the lesion area and calculate the percentage reduction. Other parameters were recorded from the charts, including clinical, radiographic and histopathology reports. Decompression reduced the lesion size by a mean 41.4%. The patients were classified according to the effectiveness of decompression (effective defined as ≥30% reduction): 27 patients were included in the effective group and 13 in the ineffective group. The average rate of reduction was 0.17% per day. An absence of bone perforation (P = 0.043) and larger initial lesion size (P = 0.034) were significantly associated with effective decompression. There was a significant association between the initial size and the reduction rate (increased reduction rate for initial size ≥10 cm2; P = 0.019). A significant linear relationship between the duration of decompression and the percentage reduction was observed (P = 0.025). These results demonstrate that UA can be treated initially with decompression, followed by other definitive treatments.