Journal of Pharmacy And Bioallied Sciences

: 2013  |  Volume : 5  |  Issue : 6  |  Page : 182--184

Hypodontia and hypoplasia of mandible: A rare defect caused by combination therapy

Senthil Kumar, Nazargi Mahabob 
 Department of Oral Medicine and Radiology, K.S.R. Institute of Dental Science and Research, Thokkavadi, Thiruchengode, Namakkal, Tamil Nadu, India

Correspondence Address:
Senthil Kumar
Department of Oral Medicine and Radiology, K.S.R. Institute of Dental Science and Research, Thokkavadi, Thiruchengode, Namakkal, Tamil Nadu


Hypodontia is defined as the developmental absence of one or more tooth and it can present in varying degrees of severity and severe hypodontia has been defined as the absence of six teeth, excluding third molars. Radiation plays an important role in the treatment of head and neck cancer, in spite of its benefits, radiation has several side-effects in the head and neck region. This article highlights a case report, where hypodontia, hypoplasia of mandible, stunded permanent teeth roots, microdontia, inversion of tooth bud were observed in 19 years old patient who was diagnosed with Langerhans cell histiocytosis at her age of 3 years she had received a combination of radiotherapy and chemotherapy for a period of 1 year and radiation of 50 Gy was used in the head and neck region. Radiographs were taken and it revealed abnormal changes in growth and development of bone and teeth.

How to cite this article:
Kumar S, Mahabob N. Hypodontia and hypoplasia of mandible: A rare defect caused by combination therapy .J Pharm Bioall Sci 2013;5:182-184

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Kumar S, Mahabob N. Hypodontia and hypoplasia of mandible: A rare defect caused by combination therapy . J Pharm Bioall Sci [serial online] 2013 [cited 2021 Jan 15 ];5:182-184
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Radiation therapy is one alternative to surgery or chemotherapy in the treatment of loco-regional control of malignant head and neck tumors. [1],[2] The adverse effects of irradiation on human adult and developing teeth has been documented widely, which are confined to the radiation site. [3] These manifestations become apparent only after a number of years. We report a case of a 19-year-old female patient, who after receiving a radiation and chemotherapy treatment at the age of 3 years had hypodontia, hypoplasia of mandible, along with it there was morphological alteration in size and shape of teeth and inversion of tooth bud.

 Case Report

A 19-year-old female patient reported to the Department of Oral Medicine and Radiology, K.S.R Dental College and Hospital with the chief complaint of missing teeth in the upper and lower jaw since childhood; she had difficulty in mastication and was feeling esthetically ill. Her medical history revealed that in her childhood she had recurrent history of fever followed, which she visited a physician and the investigation was carried out and diagnosed to have Langerhans cell histiocytosis. History reveals that she had lesions in the skull and mandible at the age of 3 years and was treated with a combination of radiotherapy and chemotherapy radiotherapy of 50 Gy was given in divided doses for a period of 1 year and chemotherapy for about 1 year, patient was under review for about 10 years with no recurrence. Her dental history was not contributory; she gave a history of spontaneous exfoliation of her few deciduous teeth, followed by delayed eruption of permanent teeth. On general examination, patient was normal in stature, appearance and gait. On extra oral examination facial asymmetry was noticed on the left side of the face (the radiation exposed side) [Figure 1] temporomandibular joint movements were normal and on right and left side deep sigmoid notch was present but more prominent on the left side. On intra oral hard tissue examination revealed clinically present 11, 13, 15, 16, 17, 23, 26, 31, 33, 34, 36, 41, 42, 43, 46, 47 and RS in 62. Hence, there was hypodontia, microdontia of all the teeth and spacing between the teeth [Figure 2] and [Figure 3].{Figure 1}{Figure 2}{Figure 3}

Orthopantomogram revealed (a) hypodontia (b) hypoplasia of mandible (c) deep sigmoid notch (d) reduced vertical height of ramus (e) stunted roots of all permanent teeth (f) inversed and impacted 34 and 44 [Figure 4]. Lateral and posteroanterior view revealed no bony lesions, but there was hypoplasia of mandible on the left side with multiple missing permanent teeth [Figure 5] and [Figure 6].{Figure 4}{Figure 5}{Figure 6}

Patient was subjected to complete hemogram, serum calcium and phosphorus, which were in normal limits.

On the basis of clinical history and radiographic examination, a diagnosis of radiation induced biological changes in bone and teeth were made.


Radiation therapy and chemotherapy may be an effective alternative to surgery or a valuable adjuvant therapy to surgery in treatment of loco-regional control of malignant head and neck tumors. [1],[4] In addition to antitumor effects, ionizing irradiation cause damage in normal tissues located in the field of radiation that is exposure to the head and neck region, a dosage of 24 Gy can cause interruption in both tooth formation and bone development. [3],[4],[5] This becomes particularly evident in the head and neck region; a complex area composed of several dissimilar structures that respond differently to radiation. [3] The effects that early irradiation can have on the development and eruption of teeth in humans are related to dosages, period of exposure, stage of tooth development and proximity of the teeth to the center of maximum dosage. [2],[3] It has been ascertained that if the radiation given during the stages of morph differentiation and calcification the tooth bud may be destroyed. Irradiation at a later stage, after calcification has been initiated may alter cellular differentiation causing malformation or arrested growth. Animal studies suggest that teeth are most vulnerable before histodifferentiation and this ceases once calcification is complete. [2],[3] The effects may include: [2]

Complete absence of teethArrested tooth formationMicrodontiaAltered morphology of the crownShortness and tapering of rootsNarrowing of pulp canalDelayed tooth eruption.And various authors have presented the side effects of radiation on dental and skeletal tissues. Kaste et al. have reported the impact of radiation and chemotherapy on dental structures, he had done a survey in 9308 survivors of which 2951 survivors reported with microdontia, hypodontia, root abnormalities and abnormal enamel formation. [6] Estilo et al. have reported the radiation effects on long term survivors with clinical and radiographic dentofacial abnormalities, which were observed are enamel defects, bony hypoplasia and disturbance of root development and formation. [7] Fränzel and Gerlach has described that high exposure to radiation of 70 Gy can cause teeth destruction. [8]


Hypodontia not only occurs in hereditary conditions, but can also occur due to injury to the developing tooth germ form radiation. Hence, radiotherapist should try avoiding exposure to the vital structures unless if necessary, buy using lead shields to cover the vital structures in the line of radiation. Professional follow-up is essential for dental health maintenance after radiotherapy and chemotherapy; radiologist can help and direct, care of long-term survivors by recognizing late side-effects of radiotherapy to provide guidance for management of dentofacial defects at an early stage. [9]


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