Radiation Biology
Discuss in detail radiation effects on oral cavity.
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Write note on radiation hazards of oral cavity.
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Describe harmful effect of radiation on oral mucosa, taste buds, salivary glands, teeth and jaw bones.
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Write in detail about radiation hazards in dentistry.
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Describe in detail about the effect of radiation on mucosa, salivary gland and bone.
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Write short answer on effect of radiation on salivary glands
Answer. Study of the effects of ionizing radiation on the living system is called as radiation biology.
Read And Learn More: Oral Radiology Question And Answers
Harmful Effect of Radiation in oral cavity/oral Mucosa
The oral cavity is irradiated during the course of healing of radiosensitive oral malignant tumors, e.g. squamous cell carcinoma.
Oral Mucosa
- Oral mucous membrane contains the basal layer of differentiating inter mitotic cells which are highly radiosensitive at the end of second week of therapy, the mucous membrane begins to show areas of redness and inflammation, this state is called as “Mucositis.”
- Asthetherapycontinuesthemucousmembranebreaksdown with the formation of white or yellow pseudomembrane.
- At the end of therapy, the mucositis is severe, painful leading to difficulty in talking, eating and swallowing.
- After termination of therapy, the healing may be complete after about two months, but the mucous membrane tends to become thin, atrophic and relatively avascular. Secondary infection by Candida albicans is very common complication.
- Patient is usually prone to oral ulcerations and unable to tolerate dentures.
Radiation Effects on Taste Buds
- Taste buds are sensitive to radiation even therapeutic dose of radiation causes degeneration of taste buds.
- Loss of taste sensation occurs during 2nd and 3rd week of therapy.
- Loss of taste sensation can be partial or complete.
- Posterior two-third of the tongue when irradiated affects the bitter and acid flavors.
- Anterior one-thirds of the tongue when irradiated affects sweet and salty flavors.
Radiation Effects on salivary Glands
- Parenchymal component of the gland is sensitive to radiation.
- Glands demonstrate progressive fibrosis, adiposis, loss of fine vasculature.
- There is marked decrease in salivary flow.
- The composition of saliva is affected.
- There is increased concentration of sodium, chloride, calcium, magnesium ions and proteins.
- Saliva losses its lubricating properties.
- Mouth becomes dry and tender due to xerostomia.
- pH of saliva is decreased which may initiate decalcification of enamel.
Radiation Effects on teeth
Adult teeth are resistant to the effects of radiation.
Radiation caries
- Involve mainly cementum and dentin at cervical lesion.
- Dark pigmentation of crown.
- Superficial lesion affect buccal, incisal, palatal and occlusal surfaces.
During development
- Before calcification: There is complete destruction of tooth bud which results in partial anodontia.
- Once calcification starts: Hypoplastic changes seen.
- During root development: Retardation or loss of root development.
After Eruption
Radiation caries: It is a form of rampant caries; it is secondary to the change in saliva.
Radiation Effects on Bone
- Marrow is replaced by bone marrow and fibrous connective tissue.
- Endosteum becomes atrophic.
- Bone becomes hypovascular hypocellular and hypomineralized.
- The complication following irradiation, i.e. “osteoradionecrosis”.
- Necrosis of bone may result in nonhealing ulcer which may occur after tooth extraction.
- Lack of osteoblastic and osteoclastic activity in endosteum.
- Mandible affects more than maxilla.
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