Cysts of the jaw l Oral radiology MCQs for dental students

Radiographic interpretation cysts of the jaw l Oral radiology MCQs for dental students 

Important points to remember in radiographic interpretation cysts of the jaw

1. Dentigerous cyst: Dentigerous cysts develop around the crown of an impacted or embedded unerupted or supernumerary tooth.
2. Cysts may undergo neoplastic transformation to an ameloblastoma called mural ameloblastoma and mucoepidermoid carcinoma. Dentigerous cyst appears as well-defined radiolucency with sclerotic borders seen. Radiographically, dentigerous cyst can be central (cyst enclosing the crown of tooth symmetrically), lateral (cyst arising laterally from one side of crown) and circumferential (when whole tooth lies within the cystic cavity).
3. Gingival cyst of newborn and adults: The cyst disappears rapidly by rupturing in the oral cavity. There are small discrete white swellings over the alveolar mucosa. There is superficial erosion of cortical plate.
4. Eruption cyst: Eruption cyst occurs mostly in first permanent molar and maxillary incisors; in some cases follicular space over the occlusal portion of the erupting tooth is increased than the normal size.
5. Lateral periodontal cyst: It is also called botryoid odontogenic cyst. It is oval or round in shape. It appears as a radiolucent area situated laterally at middle third of the affected tooth between the apex and the alveolar crest of tooth.
6. Glandular odontogenic cyst: It is also known as sialo-odontogenic cyst. The lesion shows slow, progressive, locally destructive, painless growth. The lesion appears as well-defined multilocular, occasionally unilocular radiolucency with sclerotic or scalloped borders.
7. Adenomatoid odontogenic cyst: Previously, it was called as adenomatoid odontogenic tumour. It is painless, small, sessile gingival coloured mass. It appears commonly as a unilocular radiolucency with smooth corticated borders; sometimes, it may be having sclerotic border. Sometimes, radio-opaque foci may be identified within the radiolucent region.
8. Radicular cyst: It develops as common sequelae of pulpal necrosis following caries; it is seen at apex of nonvital teeth. It is asymptomatic, radiolucent area at the apex of tooth with well-demarcated sclerotic margins unless secondarily infected. The size of radiolucency is 1 cm or more in diameter.
9. Residual cyst: Residual cysts are most commonly the retained periapical cysts from teeth that have been removed; there is well-defined unilocular radiolucency in the periapical area of extracted tooth.
10. Nasopalatine duct cyst: There is swelling in the anterior palate. Area of midline radiolucency is situated between roots of upper central incisor in nasopalatine canal. It can be round, oval or heart shaped.
11. Nasoalveolar cyst: It is also called nasolabial cyst. Cyst appears as small, unilateral swelling present lateral to the midline radiolucent area in the alveolar bone below the cyst. It can be circular or oval in shape.
12. Traumatic bone cyst: It is also called as haemorrhagic bone cyst or simple bone cyst. It presents as painless swelling; aspiration is negative. Area of radiolucency is situated in canine, bicuspid and molar regions of mandible; radiolucent lesion is well demarcated from the adjacent bone.