Abnormalities Flashcards
6 types of abnormalities of the teeth
Abnormalities in the:
- Number of teeth
- Size of teeth
- Shape of teeth
- Eruption of teeth
- Structure of teeth
- Acquired abnormalities
2 types of abnormalities of the number of teeth
Increased number of teeth
Reduced number of teeth
4 types of abnormalities resulting in increased number of teeth
- Supernumary - supplemental
- Mesiodens
- Paramolar
- Distomolar - distodens
3 types of abnormalities resulting in reduced number of teeth
- Hypodontia
- Oligodontia
- Anodontia
Where do multiple supernumary teeth more commonly occur?
In the mandible
Where do single supernumary teeth more commonly occur?
Maxilla
Define supernumaries
Additional teeth that are smaller and misshapened
Define supplemental teeth
Additional teeth of normal size and shape
Define paramolar
Supernumary tooth in the molar region
Define distomolar or distodens
Supernumary tooth occuring distal to to the third molar
Define peridens
Supernumary tooth that erupts to the bucaal or lingual of the arch
Useful imaging technique for detecting location of supernumary teeth in the mandible
Occlusal
Radiographic examination technique that is useful to determine the location of supernumary teeth location in the maxilla
SLOB rule
Define mesiodens
Supernumary tooth that develops on the maxillary midline
Describe the characteristics of mesiodens (6)
- Can prevent the eruption of central incisors
- Small tooth in a vertical, inverted or horizontal position
- Normal density of teeth
- Usually more palatal
- PDL space and lamina dura present
- Normal tooth architecture
4 skull abnormalities of cleidocranial dysplasia
- Brachycephaly (reduced AP, increased width)
- Delayed closure or open fontanelles
- Open sutures
- Wormian bones
Maxillary abnormality associated with cleidocranial dysplasia
Maxillary micrognathia:
- Maxillary hypoplasia
- Hypoplasia of maxillary sinuses
3 radiographic findings of cleidocranial dysplasia
- Prolonged retention of deciduous teeth
- Mulitple unerupted supernamary teeth resembling premolars
- Maxillary hypoplasia
4 commonly missing teeth based in decreasing order of frequency
- 3rd molars
- 2nd premolars
- Maxillary laterals
- Mandibular central incisors
3 characteristics of hypohydrotic ectodermal dysplasia
- Hypohydrosis (abnormally diminished perspiration)
- Hypotrichosis
- Hypodontia with conical teeth
Most frequently affected tooth by microdontia
Peg lateral incisor
Syndrome in which generalized micodontia can occur
Trisomy 21
Differential diagnoses for macrodontia
Fusion or gemination
Define talon cusp
T-shaped incisor edge due to a hyperplasia of the cingulum
Radiographic appearance of talon cusps
- Pulp horn may be seen extending into the cusp
- Well-defined radiopacity superimposed over the crown
Differential diagnosis for talon cusp
Mesiodens
Define dilaceration
Curved root that can compromise the success of endodontic therapy or complicate extractions
5 characteristics of taurodontism
- Found on molars
- Single or multiple teeth
- Unilateral or bilateral
- Extension of the pulp chamber, shorter roots
- Increased distance between CEJ and furcation
2 teeth most commonly affected by dens invaginatus (dens in dente)
Permanent maxillary lateral incisor
Maxillary central incisor
3 characteristics of dens invaginatus
- Prominent palatal marginal ridges or cingulus, deep cingulum pit
- Thin enamel in the invagination
- A lot of variation in the severity of involvement
Importance of recognizing dens invaginatus radiographically
To prophylactically restore the pit and prevent endodontic therapy
Tooth most commonly affected by dens evaginatus
Mandibular premolar (Leong’s premolar)
2 characteristics of dens evaginatus
Enamel covered tubercle on the occlusal surface with pulp horn
Most often occurs in people of mongoloid origin
Risk of dens evaginatus
Tubercle is removed by attrition –> Micro pulp exposure on a virgin tooth, pulp necrosis and possible periapical radiolucency
Define fusion
Fusion of 2 teeth –> reduced number of teeth on the arch. Important to examine radiographically to reveal extent of fusion and decide on management
4 forms of fusion
- One large tooth
- Bifid crowns with one root
- 2 teeth united by dentin
- Rarely, 2 teeth united by enamel
Define gemination
Division of a tooth bud of a single tooth –> normal number of teeth on the arch
Deciduous > permanent
Important to examine radiographically to reveal extent to decide on management
3 forms of gemination
- One large crown
- Crown divided by a groove
- 2 crowns with pulp chamber can be enlarged, but single, partially divided
Define concrescence
Roots of 2 teeth united by cementum. Teeth can fail to erupt or would be difficult to extract. PDL space is absent where the roots are fused. Several radiographcs me need to be taken to separate teeth
Teeth most commonly affected by concrescence
Maxillary molars
Define supernumary roots
Variation in the number of roots of teeth. Has some significance if an endodontic treatment is required
Define transposition
2 teeth exchange positions
Define secondary dentin
Deposition of new dentin after the formation of primary dentin, which are indistinguishable from each other. Normal process associated with aging. No consequence other than making endodontic therapy difficult if necessary
Radiographic appearance of secondary dentin
Reduction in the size of the pulp chamber and canal, loss of pulp horns
Define attrition
Flattening of the occlusal surface. Shortening of the height of the crown –> deposition of secondary dentin that reduces the size of the pulp chamber
Importance of the radiographic detection of attrition
To detect a possible periapical radiolucency associated witha necrotic pulp when attrition is severe
Radiographic appearance of abrasion/ abfraction
Usually seen on canines and premolars as a triangular radiolucency at the inferior aspect of the crown. Important to detect in case of periapical radiolucency with necrotic pulp when abrasion is severe
Define pulp stones
Foci of calcification in the pulp chamber. No consequence other than making endodontic therapy difficult if necessary
Radiographic appearance of pulp stones
Only large stones visible. One or more multiple round or ovoid radiopacities in the pulp chamber or canal
Define pulp sclerosis
Diffuse type of pulp calcification that increases with age
Radiographic appearance of pulp sclerosis
Diffuse irregular radiopacities in the pulp chamber and canals
Define hypercementosis
Excessive deposition of cementum on the tooth root
3 situations in which hypercementosis occurs
- Supraerupted tooth
- Inflammation
- Hyperocclusion
Condition where generalized hypercementosis is seen
Paget’s disease
Radiographic appearance of hypercementosis
Excessive amounts of cementum on the root. Cementum = less radiopaque than dentin. PDL and lamina dura around excessive cement.
4 types of amelogenesis imperfecta
- Hypoplastic
- Hypomaturation
- Hypocalcified
- Hypomaturation (hypocalcified with taurodontism)
4 possible characteristics of amelogenesis imperfecta
- Square shape of crowns
- Absent or thin enamel
- Enamel of normal thickness but more radiolucent
- Pitted enamel
2 types of dentinogenesis imperfecta
- Type I with osteogenesis imperfecta (skeletal defects)
- Type II affects only the teeth
Clinical appearance of dentinogenesis imperfecta
Teeth are yellow to grey with an amber-like translucency
Radiographic appearance of dentinogenesis imperfecta
- Normal crowns appear bulbous because of a constriction at the CEJ
- Obliteration of the pulp chambers
Clinical appearance of dentin dysplasia type I radicular
Normal color and shape of the teeth
radiographic appearance of dentin dysplasia type I radicular
- Short and abnormal shape of roots
- Obliteration of the pulp chambers of the teeth before their eruption
- Periapical radiolucencies
Clinical appearance of dentin dysplasia type II coronal
Teeth have the appearance of dentinogenesis imperfecta
Radiographic appearance of dentin dysplasia type II coronal (4)
- Normal size and shape of the roots
- Obliteration of the pulp chambers of the teeth after their eruption
- Pulp calcifications
- Flame or thistle-tube pulp chambers
Define regional odontodysplasi
Defect of anemal and dentin affecting a few adjacent teeth and not all teeth
