Age changes in residual radicular cysts.

Histological and radiographic study of 33 uninfected residual radicular cysts has shown that there is a slow increase in mineralised deposits within the cyst lumen with time. This becomes prominent histochemically in those cysts more than 8 years old and radiographically 6 years later. It would appear that mineralisation in these elderly cysts is due to dystrophic calcification of degenerate cellular material within the cyst lumen. Inflammation in all cysts, apart from mild granulomatous reactions related to cholesterol within cyst walls, was minimal. Overall reduction of cyst size with increasing epithelial atrophy and loss of hyaline bodies and mucous cells, has been shown to occur with increasing cyst age. It is suggested that the majority of radicular cysts heal spontaneously following extraction of the associated tooth. Furthermore, lesions that persist as residual radicular cysts will also undergo slow resolution if inflammation is not a prominent feature.