Tooth development in the light of chemotherapy-induced agenesis in cancer survivors

Introduction
Although the developmental model of permanent tooth is considered to be similar to the better understood formation of deciduous tooth, the duration of subsequent stages differs significantly, and it is difficult to determine. Various sources report that agenesis is a result of genetic abnormality or a developmental disturbance caused in initiation stage. However, it seems that complete damage to the germ, sometimes referred to as “aplasia”, can occur during the entire early odontogenesis. Detailed antineoplastic treatment records and dental disturbances in children as a result of chemotherapy administration show the possibility to recognize not well-known early tooth development. Objectives: An attempt to discover some unexplained facts about early tooth development based on the cases of chemotherapy-induced agenesis.

Material and methods
Thirty-eight cancer survivors presented for a check-up visit in the Pediatric Clinic fulfilled the study criteria. Clinical control and panoramic radiograph were performed to identify the developmental abnormalities of hard tissues. Medical records were also analyzed to distinguish the age and duration of the cytotoxic treatment. Thirty-one survivors showed long-term dental effects of therapy. Five participants had 13 teeth missing.

Results
In the case of survivors with a lack of 6 teeth, germ-toxic drug administration was applied just before appositional growth. Individuals with 3 teeth missing started the therapy before or at the beginning of expected initiation stage. One patient with four second premolars missing was treated outside the early odontogenesis age period.

Conclusions
Detailed analysis revealed hypothesis that the total toxic damage to the dental developing tissues is likely to occur even at the most advanced stadium of early development. A longer duration of early odontogenesis is also possible. The duration of particular stages in tooth formation can be revised based on the dental examination of cancer survivors.