Micrognathia after radiation therapy for childhood facial tumors

Department of Pediatric Dentistry

Lutheran Medical Center

Date: 01/22/2010

Article title: Micrognathia after radiation therapy for childhood facial tumors

Author(s): Kaste SC, Hopkins KP

Journal: Oral Surg Oral Med Oral Path

Volume (number): 77:95-99

Month, Year: 1994

Major topic: Affect of radiation therapy on oral structures

Minor topics: Dental management of pts under radiation therapy

Type of Article: 2 cases and long-term follow-up

Main Purpose: Educate readers on the consequences of radiation therapy

Overview of method of research: Review of current treatment modalities and case review

Findings: Radiation-induced dental effects include maxillary and mandibular hypoplasia, tooth or root dwarifsm, anodontia, caries and altered tooth eruption patterns. Additionally, radiation causes osteocyte death, microvascualr injury, periosteal damage and fibrous replacement of marrow spaces with all affect bone growth and development. The impact and severity of these treatments are depend on the child’s age at time of therapy, the radiation dose, and anatomical location of treatment.

Radiation doses of 10Gy and 30Gy have been shown to permanently damage ameloblasts. And studies have shown that does in excess of 20 Gy can result in significant bone and growth disturbance, regardless of age. It is particularly damaging if therapy in done during times of significant patient growth.

Knowing the late effects of radiation treatment to oral (or near oral) structures can aid clinicians in anticipatory guidance and help them better manage patients and improve their quality of life.

Key points/Summary :

Case 1:

4yr old boy with an extra-abdominal desmoid tumor on the palate. He received 32 Gy in addition to chemotherapy. Lateral Ceph at the time of treatment revealed a “normal” skeletal relationship of the maxilla and mandible.

At age 6, mandiblar lysis, root agenesis and stunting of root development of radiographically evident.

At age 12, radiographs revealed over-retained primary teeth, and displaced permanent molars. Significant mandibular micrognathia was present and overjet with severe.

At age 17 micrognathia was apparent and microdontia of all permanent 2nd molars was present. The crowns of the 3rd molars were displaced high in the ramus.

Case 2:

5 year old with embryonal rhabdomyosarcoma arising in the right nasopharynx. Threated with 35Gy and chemotherapy.

At age 15 he showed generalized root stunting, malposition of maxillary teeth and significant maxillary hypoplasia with facial disproportion. Some anodontia was also present.

Assessment of article: Very interesting. This would be a very interesting and challenging population to treat. The article never addressed what, if any, dental treatment was offered to these patients. That would be interesting to know, since the article suggested that dentists could improve the patient quality of life through proper management.