Lecture 6 - Developmental Abnormalities Flashcards
Impacted
Will not erupt
Usually blocked by bone
Unerupted
Hasn’t erupted
Not blocked
Transposition
Tooth position switch with another
Not common
Max. canine/bicuspid is most commmon
Supernumerary teeth
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
Supplemental tooth
Supernumerary tooth that is morphologically normal
Mesiodens
Supernumerary tooth b/t maxillary central incisors
Most common supernumerary tooth
Usually palatal
Peridens
Supernumerary tooth in premolar area
Mandibular peridens is second most common supernumerary
Distodens
Supernumerary tooth in molar area
Ddx associated with Supernumerary tooth
Cleidocranial dysplasia Pykodysostosis Gardner’s syndrome • Osteoma’s • Supernumeraries • Impacted teeth • Colon polyps/cancer
Common missing teeth
Third molars most common
Lateral and mandibular second bicuspid second most common
Ddx associated with missing teeth
Ectodermal dysplasia
Microdont/Peg lateral
Small tooth
Generally only in maxilla
Fully-formed/normal anatomy
Megadont/Macrodont
Big tooth
Fully-formed/normal anatomy
Fusion
Missing tooth fused w/ existing tooth
Complete or incompletely fused roots and/or crowns
Pt will have one less tooth
Gemination
Two teeth develop from one tooth bud
Will not be missing a tooth
Partial or complete division through crown and root
Concrescence
Teeth joined by excess cementum
Max. 3rd molars
Rare
Taurodont
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
Dilaceration
Abnormal angulation or sharp bend of the root or tooth
Due to trauma when tooth is forming
Most often max. premolars
Tooth within a tooth
Dens invaginatis < dens in dente < dilated odontome (most “severe”)
Max. lateral incisor is most common
Dens evaginatus/Leong’s premolar
Extra cusp
Pulp of tooth may extend too
Mand. premolar is most common
May need root canal if breaks off
Enamel pearl
Pearl of enamel where it shouldn’t be
Most common on max. molars
Usually in furcation of molars from Hertwig’s epithelial root sheath
Enamel hypoplasia
Tooth enamel is hard, but thin and not enough
Amelogenesis imperfecta
Abnormal formation of enamel
Malfunction of ameloblastin, enamelin, tuftelin, and amelogenin
Teeth abnormally yellow, brown, or grey
Caries and hypersensitivity
Dentin dysplasia Type 1
Radicular Absence of pulp chamber Normal clinical crown morphology/color Short, blunted roots AD
Dentin dysplasia Type 2
Coronal
Primary dentition similar to Type 2 DI
Permanent dentition has abnormal pulp morphology and pulp stones
AD
Dentinogenesis imperfecta
Discolored teeth, blue-grey or yellow-brown
Opalescent
Enamel usually chips off
DI Type 1
Associated with OI
Absence of pulp chamber/canals
Bell-shaped crown
Short, blunted roots
DI Type 2
Hereditary opalescent dentin
Not associated w/ other disorders
Absence of pulp chamber/canals
Abnormal crown/root morphology
DI Type 3
Rarest form of DI "Shell teeth" Large pulp chambers, thin dentin, thin enamel Bell shaped crown Diminished root structure
Hypophosphatasia
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
Hypercementosis
Excessive buildup of normal cementum on roots “PIG ON TAP” - Paget’s disease - Idiopathic - Gigantism - Occlusal trauma - Non-functional Tooth trauma - Acromegaly - Periapical granuloma
Pulp Stones
Calcified masses in pulp chamber
No clinical significance, makes endo harder
Ddx: calculus, enamel pearl
