Clinical Radiology - Developmental Anomalies Flashcards
What are the 4 categories of dental anomalies?
Eruption/position
Shape/size
Number
Structure
Movement of a tooth from its position of development to its functional location in the mouth
Eruption
After the tooth is in full occlusion, slight ___________ continues to compensate for normal attrition and continued __________ growth of the face
eruption; vertical
Emergence has not occurred within 12 months of normal range or when 75% of root is formed
Delayed eruption
What are the 2 systemic causes of delayed eruption?
Endocrine disorders
Syndromes (Gardner, cleidocranial dysplasia, ectodermal dysplasia, Down’s)
What are the 3 local causes of delayed eruption?
Physical barrier
Abnormal position
Trauma
Rare non-syndromic eruption disorder where the tooth fails to erupt in the absence of any mechanical obstruction
Primary failure of eruption
Disturbance of tooth eruption that results from fusion of cementum or dentin with alveolar bone
Ankylosis
Cessation of eruption because of mechanical interference caused by a physical barrier
Impaction
Which 2 teeth are most affected by impaction?
3rd molars and canines
What word is sometimes used as a synonym for non-erupted (embedded)?
Impaction
What’s the ratio for location (labial/palatal) of impacted canines?
1/3 labial
2/3 palatal
What are the 2 types of dental anomalies related to position?
Orientation (tooth axis)
Location
What are the types of malpositions of teeth?
Mesially angulated
Distally angulated
Transverse (buccolingual)
Horizontal
Inverted
Rotated
Tooth develops in ectopic location or does not follow its usual eruption course
Ectopic
Where are ectopic teeth most commonly found?
Alveolar process
Where are ectopic teeth found in rare cases?
Non-dentate regions
Change in order/position between 2 adjacent teeth in the dental arch
Transposition
Is transposition found in primary dentition?
No
Which 2 teeth most commonly experience transposition?
Upper canines and 1st molars
What category does “transposition” and “transmigration” fall under?
Ectopic
Displacement of teeth across midline
Transmigration
What teeth most commonly experience transmigration?
Lower canines
Unassisted migration of teeth within alveolar process mesially, towards midline
Physiological drift
Tendency of teeth to move mesially to maintain contact between teeth
Physiological drift
Is physiological drift a developmental anomaly?
No!
What does physiological drift cause changes in?
Occlusal plane
Excessive # of teeth
Supernumerary teeth/hyperdontia
Missing teeth (does not include 3rd molars)
Agenesis
What are the 3 types of agenesis?
Hypodontia (1-5 missing)
Oligodontia (6+ missing
Andodontia (all 32 missing)
Supernumerary teeth are often __________ or _________
embedded; unerupted
Supernumerary teeth have variable numbers, size, and locations, and tend to have variable ____________
morphology
Supernumerary tooth in the incisor region of the maxilla
Mesiodens
Supernumerary tooth in the molar region of the maxilla
Paramolars
Supernumerary tooth posterior to the 3rd molars
Distomolars (also called 4th molars)
Unusually large
Macrodontia
Unusually small
Microdontia
Types of dental anomalies in regards to shape of crown
Dens invaginatus
Dens evaginatus
Enamel pearl
Fusion
Germination
Types of dental anomalies in regards to shape of root/pulp chamber
Concrescence
Supernumerary roots
Taurodontism
Dilaceration
“Tooth within a tooth” - dens in dente
Dens invaginatus
Invagination of the enamel surface into the interior aspect of the tooth
Dens invaginatus
What is the order for teeth most affected by dens invaginatus?
Lateral incisors > central incisors > premolars > canines > molars
What are teeth with dens invaginatus filled with during development? What happens after eruption?
Soft tissue; becomes necrotic after eruption
After a tooth with dens invaginatus erupts, there is a potential space for entrapment of food debris and bacteria, making this tooth prone to what? What does this lead to?
Caries -> leads to apical periodontitis
Which type of dens invaginatus?
Confined to crown
Type I
Which type of dens invaginatus?
Extends below CEJ as blind sac, +/- pulp
Type II
Which type of dens invaginatus?
Transverses root, perforates laterally
Type IIIa
Which type of dens invaginatus?
Transverses root, perforates apically
Type IIIb
Most severe form; anomalous shape
Dilated odontoma
Evagination of enamel, causing an additional tubercle or cusp
Dens evaginatus
Additional cusp on posterior tooth
Leong premolar, occlusal pearl, evaginated odontoma
Which teeth are most commonly associated with dens evaginatus?
Mandibular premolars
Maxillary incisors
Name the characteristics of premolars affected by dens evaginatus
Central groove or lingual ridge
Usually bilateral
Pulpal extension common (can lead to pulpal pathosis)
Additional cusp on anterior teeth
Talon cusp, Eagle’s talon, supernumerary cusp
Which surface is the additional cusp usually found on for anterior teeth?
Lingual surface
In dens evaginatus, the extra cusp on anterior teeth extends at least ____ the distance from the CEJ to the incisal edge
1/2
Ectopic hemispherical bulging on root surface
Enamel pearl
Well defined, small, radiopaque nodule on root surface, usually at furcation
Enamel pearl