Dental Anomalies I: Number, Shape, Size Flashcards
What is the prevalence of hyperdontia?
- M>F 2:1
- More often seen in permanent dentition
- 95% at anterior maxilla
What are the classifications of supernumeraries?
- Mesiodens: between upper central incisors
- Paramolar: buccal/lingual to max molar
- Distomolar: distal to 3rd molar
What are the different forms of supernumeraries?
- Conical: sharp
- Supplemental: looks exactly like permanent tooth
- Tubercle: barrel shaped
What syndromes is hyperdontia associated with?
- Cleidocranial dysplasia
- Gardner syndrome
- Cleft lip and palate (~40% have supernumeraries in area of cleft)
What are associated problems of hyperdontia?
- Impede/deflect eruption of permanent teeth
- Crowding/malalignment
- Resorption of root of adjacent teeth
- Cyst may develop around buried supernumerary teeth
What is the management of hyperdontia?
- Removal of supernumerary
- When root of adj permanent tooth is 1/2 to 3/4 formed - Leave alone and review
- If tooth is buried + inverted => unlikely to erupt
- Take x-ray in 3 years to look for signs of cystic growth
What are the types of hypodontia?
- Hypodontia: missing ≥1
- Oligodontia: missing ≥6
- Anodontia: no teeth
What is the prevalence of hypodontia and which teeth are most affected by hypodontia?
F>M
Terminal teeth of a series:
8s > lower 5s > upper 2s > upper 5s > lower 1s
What are syndromes associated with hypodontia?
- Ectodermal dysplasia
- Cleft lip/palate
- Trisomy 21
Often occurs with microdontia
What is the management for hypodontia?
- Clinical & radiographic assessment +> referral
- Regular preventive care – must maintain few teeth left
- Restore aesthetics / function => multi-disciplinary approach (eg prostho, ortho)
Which teeth are most likely to have accessory/extra roots?
Lower 6s, canines and PMs
- May complicate exo, ortho, endo
What is the prevalence of reduction in number of roots and which teeth are most affected?
F>M
7s and 8s
Which is the only dental anomaly that is more common in primary dentition, and which teeth does it most commonly occur in?
Double tooth, incisors
What are the causes of double tooth and how do you differentiate between them?
Gemination or fusion, can be distinguished:
- Radiographically
- By counting the number of teeth in the arch
What is the presentation of gemination?
- Budding of second tooth from single tooth germ
- Usually 1 root canal present
- Bifid crown with single root and pulp chamber
- Familial inheritance
- Normal number of teeth in arch
What is the presentation of fusion?
- Joining of 2 teeth of the normal series or a normal tooth and a supernumerary by pulp and dentine
- 2 canals present
- Tooth has arisen from 2 tooth germs => number of teeth in dentition usually reduced by 1 unit
What is the clinical significance of double tooth?
Possibility of same condition in permanent dentition
What is the management for double tooth in primary teeth?
- Site of fusion => deep groove => increased risk of plaque collection => may require FS
- Monitor root resorption of primary double tooth => may retard eruption of permanent successor
What is the management for double tooth in permanent dentition?
- For permanent dentition, separation of fused teeth (fusion), reshaping or reduction (gemination) may be possible
- If not, deliberate extraction and prosthodontic replacement
What is concrescence? (etiology, prevalence, clinical significance)
- Joining of 2 teeth by cementum
- Fusion occurs after root formation is completed
Most common in maxillary posterior region
Significance: difficult extraction
What are 3 dental anomalies of accessory cusps?
- Talon’s cusp: cusp projecting from cingulum of incisors
- Cusp of Carabelli: on mesio-palatal of 6s, usually bilateral
- Paramolar tubercle/cusp: extra cusp on buccal of molars
What is the prevalence of dens invaginatus?
M>F
Most commonly in upper lateral incisor
What is the clinical significance and management of dens invaginatus?
- Caries may develop in invaginatus
- Enamel lining of invaginatus may have incomplete enamel lining & deficient dentine => lead to pulpal infection
Mx: Prophylactic FS soon after eruption
Which tooth is dens evaginatus most commonly seen?
Premolars (Leong’s premolar), sometimes canines and molars
What is the clinical significance and management for dens evaginatus?
Tubercle may fracture => pulpal infection
- Not in occlusion: reinforce w CR => allows for slow wearing instead of fracture
- In occlusion: PRR w pulpal protection (e.g Ca(OH)2 lining)
What is taurodontism?
Molar tooth with pulp chamber that is vertically enlarged at the expense of roots => enlarged chamber & short roots (detected radiographically)
What syndromes are associated with taurodontism?
- Ectodermal dysplasia
- Klinefelter’s syndrome (XXY)
- Amelogenesis Imperfecta (20% of cases)
What is dilaceration and what is its etiology?
Abrupt deviation of the long axis of the crown or root portion
Etiology:
- Trauma to primary dentition (around 2-5 yo)
- Idiopathic or developmental disturbances
What is the clinical significance and management of dilacerations?
- If mild, tooth may erupt => reshape for aesthetics
- If fail to erupt => track down orthodontically/remove surgically (ortho consult to determine if tooth worth tracking down)
If dilacerated at crown => may not erupt
If dilacerated at root => hard for orthodontic movt
Which dental anomalies are seen in congenital syphilis?
Hutchinson’s incisors:
- Barrel shaped (cervical width > incisal edge)
- Incisal angles rounded, edge may be notched
Moon’s molars
- Reduction of crown form towards occlusal surface of 6s
Mulberry molars
- Hypoplasia of early mineralising parts of 6s
What is globodontia?
Globular deformity of crowns of canines & posterior teeth of both dentitions
What syndromes are associated with globodontia?
Otodental syndrome:
- Hereditary disorder
- Characterised by hearing loss (high frequency deafness from childhood) & globodontia
Which teeth does microdontia most commonly affect?
Permanent upper 2s; 5s, 8s
What syndromes are associated with microdontia?
- Ectodermal dysplasia
- Down’s syndrome
- Pituitary dwarfism (generalised microdontia – rare)
Microdontia often occurs with hypodontia
Which teeth does macrodontia most often affect?
Permanent upper 1s, lower 5s
How to differentiate macrodontia from double tooth?
Macrodontia: absence of incisal notching and pulpal bifurcation
What syndromes are associated with macrodontia?
- Klinefelter syndrome (taurodontism also)
- Hereditary gingival hyperplasia
- On affected side of hemifacial hyperplasia
- Pituitary gigantism
What is the prevalence of increased root size?
M>F 5:1
Most common in upper canines
May occur with macrodontia
What is decrease in root size associated with?
- Dentine & pulp dysplasia
- Hypoparathyroidism
- Excessive irradiation of jaw during
root formation
