30 - Anomalies in tooth development

Question 1

Anomalies in the development of teeth

Answer 1

• Abnormalities in number of teeth
• Abnormalities in size of teeth
• Defects in Shape of teeth
• Defects in localisation of the teeth
• Abnormalities in structure of teeth

Question 2

Etiology of teeth anomalies

Answer 2

Errors in genetic control

Effect of the environment

Many syndromes

Question 3

Anomalies in number of teeth

Answer 3

These are a result of different etiologic factors during initiation + proliferation of the dentition

This is a result of genetic factors, influence of environment + evolution

Question 4

Types of anomalies in the number of teeth

Answer 4

• Hypodontia ⇢ several missing teeth (<6)
• Oligodontia ⇢ Missing >6 teeth
• Anodontia ⇢ Missing all teeth
• Psuedo Hypodontia ⇢ lack of teeth due to retention of bone

These anomalies can affect both dentitions. Most often absent is 3rd molar, 2nd premolars, upper lateral incisors + lower central incisors

Mostly in permanent dentitions ⇢ lack of 1° = lack of permanent

Question 5

Etiology of anomalies in number of teeth

Answer 5

These abnormalities are a result from the destructions of dental lamina from early stages of embryogenesis

Destruction is caused by local, systemic or genetic factors:

• Hypo-/Anhidrotic Ectodermal Dysplasia ⇢ defects in hair, skin, nails + sweat glands ⇢ do not sweat + temp rises to 41°

Supernumerary teeth ⇢ more significant number of teeth than usual affecting mainly permanent + maxillary teeth. usually they are not symmetrical

Mesiodens ⇢ a supernumerary tooth located between upper central incisors ⇢ conical shape

Neonatal teeth ⇢ Extra teeth present at birth ⇢ results from disturbances during BUD stage

Question 6

Abnormalities in size of teeth

Answer 6

Due to etiological factors during morpho-differentiation

Microdontia ⇢ Teeth are smaller than normal

• Disturbance in BUD stage
• Real + Relative microdontia
• Due to genetic factors, hypopituitarism + downs syndrome + ectodermal dysplasia
• Most commonly seen in conical teeth + 3rd molar

Macrodontia ⇢ Teeth bigger than normal

• Also real + relative macrodontia
• Due to pituitary gigantism, otodental syndrome + hyperinsulinism
• Affects mostly men

Question 7

Abnormalities in shape of tooth

Answer 7

Dental germination ⇢ Developing tooth splits into 2 separate teeth

• Usually results in a large tooth crown that has 1 root + 1 canal
• When 2 teeth develop from 1 tooth bud

Dental Fusion ⇢ 2 teeth fuse into 1 tooth

• reduces number of teeth
• commonly affects upper 2nd/3rd molars
• Difficult to extract these teeth

Question 8

Additional cusps

Answer 8

Karabelli’s cusp ⇢ extra mesiolingual cusp on upper molars w/individual pits + fissures

Talon cusp ⇢ cusp that projects lingually from cingulum of permanent incisors

Dens evaginatus ⇢ Tooth within a tooth ⇢ disturbance during BELL stage

• Appears as central cusp located at central groove or at lingual edge
• Affects mandibular molars + premolars
• Results from disturbances during CAP stage

Enamel pearls ⇢ maxillary molars ⇢ deepening of enamel in CEJ in bifurcation

Taurodontism ⇢ expansion of pulp, ⇡ pulp from apical to occlusal dimension ⇢ premolars, molars