Background. Deficient dental root development has been reported after conventional pediatric anticancer therapy but less information is available on children with solid tumors and lymphomas. Procedure. We examined dental development from panoramic radiographs (PRGs) of 37 childhood cancer survivors (CCS) treated under the age of 10 years with multimodal chemotherapy (CT) and/or head and neck radiotherapy (RT). A novel defect index (DeI) was used to describe the total damage to permanent dentition. The DeI was also tested in matched controls. Results. All CCS had dental disturbances including abnormal root development (86.4%), microdontia (13.5%) and tooth agenesis (16.2%). Testing the controls gave the mean DeI value 1.9 +/- 2.7(range, 0-12), while the index scores in the study group varied from 0 to 49 (mean 10.8 +/- 11.2) (P < 0.01). The statistical differences in the mean DeI values were insignificant between CT and CT and RT groups (P > 0.05). Conclusions. Children treated for solid tumors and lymphomas are at considerable risk of some disturbances in developing dental structures. RT increased the severity of disturbances induced by CT. Studies should further elucidate dose-, age and time-related effects of anticancer treatment on dental development. Pediatr Blood Cancer 2012; 58: 80-84. (C) 2011 Wiley Periodicals, Inc.