Lecture 6 - Developmental Abnormalities

Question 1

Impacted

Answer 1

Will not erupt

Usually blocked by bone

Question 2

Unerupted

Answer 2

Hasn’t erupted

Not blocked

Question 3

Transposition

Answer 3

Tooth position switch with another
Not common
Max. canine/bicuspid is most commmon

Question 4

Supernumerary teeth

Answer 4

Extra teeth
Result of excess dental lamina
More common in permanent dentition than primary
Can cause: misalignment, root resorption, dentigerous cysts
1-4% of population
> Asians, Native Americans
2:1 Male

Question 5

Supplemental tooth

Answer 5

Supernumerary tooth that is morphologically normal

Question 6

Mesiodens

Answer 6

Supernumerary tooth b/t maxillary central incisors
Most common supernumerary tooth
Usually palatal

Question 7

Peridens

Answer 7

Supernumerary tooth in premolar area

Mandibular peridens is second most common supernumerary

Question 8

Distodens

Answer 8

Supernumerary tooth in molar area

Question 9

Ddx associated with Supernumerary tooth

Answer 9

Cleidocranial dysplasia
Pykodysostosis
Gardner’s syndrome
• Osteoma’s
• Supernumeraries
• Impacted teeth
• Colon polyps/cancer

Question 10

Common missing teeth

Answer 10

Third molars most common

Lateral and mandibular second bicuspid second most common

Question 11

Ddx associated with missing teeth

Answer 11

Ectodermal dysplasia

Question 12

Microdont/Peg lateral

Answer 12

Small tooth
Generally only in maxilla
Fully-formed/normal anatomy

Question 13

Megadont/Macrodont

Answer 13

Big tooth

Fully-formed/normal anatomy

Question 14

Fusion

Answer 14

Missing tooth fused w/ existing tooth
Complete or incompletely fused roots and/or crowns
Pt will have one less tooth

Question 15

Gemination

Answer 15

Two teeth develop from one tooth bud
Will not be missing a tooth
Partial or complete division through crown and root

Question 16

Concrescence

Answer 16

Teeth joined by excess cementum
Max. 3rd molars
Rare

Question 17

Taurodont

Answer 17

Huge pulp chambers
Body of tooth and pulp chamber enlarged vertically at the expense of the roots
Caused by failure or late invagination of Hertwig’s epithelial root sheath

Question 18

Dilaceration

Answer 18

Abnormal angulation or sharp bend of the root or tooth
Due to trauma when tooth is forming
Most often max. premolars

Question 19

Tooth within a tooth

Answer 19

Dens invaginatis < dens in dente < dilated odontome (most “severe”)
Max. lateral incisor is most common

Question 20

Dens evaginatus/Leong’s premolar

Answer 20

Extra cusp
Pulp of tooth may extend too
Mand. premolar is most common
May need root canal if breaks off

Question 21

Enamel pearl

Answer 21

Pearl of enamel where it shouldn’t be
Most common on max. molars
Usually in furcation of molars from Hertwig’s epithelial root sheath

Question 22

Enamel hypoplasia

Answer 22

Tooth enamel is hard, but thin and not enough

Question 23

Amelogenesis imperfecta

Answer 23

Abnormal formation of enamel
Malfunction of ameloblastin, enamelin, tuftelin, and amelogenin
Teeth abnormally yellow, brown, or grey
Caries and hypersensitivity

Question 24

Dentin dysplasia Type 1

Answer 24

Radicular
Absence of pulp chamber
Normal clinical crown morphology/color
Short, blunted roots
AD

Question 25

Dentin dysplasia Type 2

Answer 25

Coronal Primary dentition similar to Type 2 DI Permanent dentition has abnormal pulp morphology and pulp stones AD

Question 26

Dentinogenesis imperfecta

Answer 26

Discolored teeth, blue-grey or yellow-brown Opalescent Enamel usually chips off

Question 27

DI Type 1

Answer 27

Associated with OI Absence of pulp chamber/canals Bell-shaped crown Short, blunted roots

Question 28

DI Type 2

Answer 28

Hereditary opalescent dentin Not associated w/ other disorders Absence of pulp chamber/canals Abnormal crown/root morphology

Question 29

DI Type 3

Answer 29

``` Rarest form of DI "Shell teeth" Large pulp chambers, thin dentin, thin enamel Bell shaped crown Diminished root structure ```

Question 30

Hypophosphatasia

Answer 30

Can't remineralize bone b/c of phosphatase deficiency in osteoblasts and chondrocytes Clinical appearance like rickets: Apical lesions without caries - Aplasia, hypoplasia, or dysplasia of dental cementum - Premature loss of deciduous teeth - “shell teeth” = enlarged pulp chambers and root canals

Question 31

Hypercementosis

Answer 31

``` Excessive buildup of normal cementum on roots “PIG ON TAP” - Paget’s disease - Idiopathic - Gigantism - Occlusal trauma - Non-functional Tooth trauma - Acromegaly - Periapical granuloma ```

Question 32

Pulp Stones

Answer 32

Calcified masses in pulp chamber No clinical significance, makes endo harder Ddx: calculus, enamel pearl