Odontogenesis- Clinical considerations Flashcards
What are some initiation stage disturbances? Where do they occur?
Occur in the dental lamina
Anodontia (hypodontia)
Supernumerary Teeth (hyperdontia)
What is anodontia?
Absence of one or more teeth
Max laterals and third molars most often affected
Complete anodontia= rare, absence of all teeth
What are supernumerary teeth?
Extra teeth in the permanent dentition
More than 32 teeth, often smaller in size
What are some bud stage disturbances?
Microdontia (partial or complete)
Macrodontia (partial or comeplete)
What is microdontia?
Teeth are smaller in size
affects permanent max lateral incisors/ 3rd molars w/ partial microdontia
What is macrodontia?
Teeth are larger in size
What are some cap stage disturbances?
Dens in Dente
Germination
Fusion
Tubercle
What is dens in dente?
Enamel organ invaginates into the dental papilla
Forms a tooth within a tooth
Affects permanent anteriors
What is germination?
Forming tooth germ tries to divide causing incomplete formation of 2 teeth
Large crown with twinning and one large root
Affects permanent and primary anteriors
What is fusion?
Union of 2 separate teeth. Common in primary anteriors
Pressure or physical force produces contact between forming tooth germs
Complete= one large single tooth Incomplete= Union of ROOTS ONLY (2 crown)
What is a tubercle?
Enamel extension forming an extra cusp
Found on facial/lingual anteriors and buccal/occlusal posteriors
What are some apposition & maturation disturbances?
Enamel dysplasia Concrescence Supernumerary root Accessory canals Dilaceration Enamel pearls
What is enamel dysplasia?
Faulty enamel development ameloblasts Enamel pitting (hypoplasia) Intrinsic color changes (hypocalcification) w/ changes in enamel thickness
What is concrescence?
A form of fusion that occurs after root formation is complete
Caused by trauma/crowding, causing roots to contract
Roots united by cementum only- two crowns, one large root
What are supernumerary roots?
Additional roots, usually with 3rd molars
What are accessory canals?
Additional pulp canals that form when parts of HERS breaks down before dentin formation is complete.
Canals become innervated with blood vessels and sensory nerves
Apical 3rd of root
What is dilaceration?
Occurs in the molars
Sever, sharp curving or bending of the roots
Caused by trauma– difficult to perform root canal or do extractions
What are enamel pearls?
Ectodermal disturbance
HERS does not break down. Cementoblasts cannot pass through, causing ameloblasts to form from IEE layer of HERS, producing enamel instead of cementum
Found at CEJ & in furcation areas
What type of tissue is affected by amelogenesis imperfecta? Which cells are disturbed?
Affects enamel. Ectodermal disturbance
What are the different types of amelogenesis imperfecta?
Hypoplastic
Hypocalcification
Hypomaturation
Hypoplasia/taurodontism
What is hypoplastic amelogenesis imperfecta?
Affects the matrix- enamel is thin to absent
Hypo-calcification amelogenesis imperfecta
Affects mineralization of matrix
Enamel is soft and wears away easily (may abrade easily by prophy)
Hypo-maturation amelogenesis imperfecta
Causes incomplete crystallization
Enamel may be easily pierced w/ an explorer and/or chipped away
Hypoplasia/taurodontism amelogenesis imperfecta
Enamel is slightly thin w. LARGE PULP CHAMBERS and enamel is hyper-mineralized
Appearance of amelogenesis imperfecta
May/may not show discoloration
Texture is chalky to cheesy (very soft to relatively hard)
Open contacts w/ severely abraded occlusal and incisal edges
Open anterior bite common
What type of tissue is affected by dentinogenesis imperfecta? Which cells are disturbed?
Affects the dentin. Ectomesenchymal disturbance
How many types of dentinogenesis imperfecta are there? What are they?
3 types
Type 1: W/ osteogenesis imperfecta
Type2: Hereditary opalescent dentin (MOST COMMON)
Type 3: Brandywine type- rare & isolated to MD
What is the appearance of dentinogenesis imperfecta?
Gray to brownish violet- translucent opalescent hue
Enamel may chip away- abnormal interlocking between enamel and dentin
Exposed dentin wears away, especially on incisal and occlusal surfaces
What is dentin dysplasia?
Hereditary, ectomesenchymal disorder
Normal enamel w/ atypical dentin and abnormal pulp morphology
2 types
Characteristic appearance of dentin dysplasia type 1
Radicular- “w” pattern in roots that is lost early on- pulp chamber is obliterated
“Rootless teeth”
Abnormally short roots, blunt shape, conical or malformed
Characteristic appearance of dentin dysplasia type 2
Coronal- relatively normal roots/pulp chambers but pulp chambers can be large and contain an increased # of generalized pulp stones
Appearance of dentin dysplasia
Crowns appear normal, may have an amber color
Normal eruption
Increased mobility, early exfoliation & high incidence of tooth loss due to trauma
What are dentigerous cysts?
A developmental cyst that forms over an unerupted tooth.
Ectodermally derived from cell rests of Serres, Malassez or reduced enamel epithelium
Cellular characteristics of dentigerous cysts
Cysts are lined with non-keratinized squamous epithelium
Fluid forms between the reduced enamel epithelium and the formed enamel
Appearance of dentigerous cysts
Varying sizes, and may be asymptomatic
Clinically may exhibit a palpable mass w/ displaced teeth
Often found on routine radiographs- radiolucency surrounding unerupted tooth
What is the treatment for dentigerous cysts?
Complete removal of the cyst and involved tooth
Marsupialization: drain fluid, allow bone growth, then enucleate cyst. This may be used to allow the tooth to erupt
What are eruption cysts?
Less serious dentigerous cyst.
Associated with erupting primary and permanent teeth
Forms over the crown, resolves w/ eruption
What is an ameloblastoma and what do they originate from?
Large ectodermal tumor of odontogenic origin that forms in the jaw near the molars and is usually associated with impacted teeth and dentigerous cysts
Forms from cell rests; Serres, Malassez, REE
Central bone lesion
What is the appearance and treatment of an ameloblastoma?
Expands the alveolar ridge causing asymmetry
Asymptomatic
On radiographs will have a translucent, compartmentalized appearance.
Treatment is complete surgical removal of the lesion and involved teeth
What is an odontoma?
Tumor of odontogenic origin
Contains mixed tissues- enamel, dentin, pulp, cementum
Associated with impacted teeth and unerupted teeth
Causes are unknown but may be from localized trauma, infection, inheritance, or genetic mutation
What are the two types of odontomas?
Compound: calcified dental tissues, resemble teeth
Complex: Calcified dental tissues; amorphous
Appearance and treatment of odontomas
Expansion of alveolar ridge
Found in both arches
Asymptomatic
Situated btw roots of teeth, usually does not cause resorption
Treatment is surgical excision
