Effect of Anticancer Therapy on Ectopic Eruption of Permanent First Molars

Purpose: The purpose of this study was to investigate the association between anticancer therapy and ectopic eruption of permanent first molars (PFMs). Methods: This study evaluated 564 five- to seven-year-old patients (anticancer therapy group=76; control group=488) who had radiographs taken between October 1, 2009 and September 30, 2010. The prevalence of ectopic eruption of PFMs was compared between the anticancer therapy group and control group. In the anticancer therapy group, the association between ectopic eruption and radiation therapy, hematopoietic stem cell transplantation (HSCT), and age at the start of treatment was also evaluated. Results: The overall prevalence of ectopic eruption was approximately six percent, with a significantly higher rate in the anticancer therapy group (~16 percent) than in the control group (~five percent; P<.001). Supplementary radiation therapy and HSCT did not significantly influence the prevalence. Patients who started anticancer therapy after three years old, however, had a lower rate of ectopic eruption than patients who started earlier (P<.05). Conclusions: The prevalence of ectopic eruption of permanent first molars increased in patients with anticancer therapy. This effect was greater in children who started anticancer therapy before they were three years old.