tooth stages and disorders lecture 6 Flashcards
induction; ectoderm lining stomodeum gives rise to oral epithelium and then to dental lamina; adjacent to deeper ectomesenchyme, which is derived from the neural crest cells. both tissue types are separated by a basement membrane
initiation stage at week 6-7
proliferation; growth of dental lamina into bud shape that penetrates growing ectomesenchyme
bud stage at week 8
proliferation, differentiation, morphogenesis; formation of tooth germ as enamel organ forms into cap shape that surrounds inside mass of dental papilla, with an outside mass of dental sac, both from the ectomesenchyme
cap stage at ninth to tenth week
proliferation, differentiation, morphogenesis; differentiation of enamel organ into bell shape with four cell types and dental papilla into two cell types
bell stage at eleventh to twelfth week
induction, proliferation; dental tissue types secreted in successive layers as matrix
apposition stage at various times
maturation; dental tissue types fully mineralize to mature form
maturation stage at various times
occurs in the initiation stage; absence of permanent or primary teeth that commonly include permanent third molar, maxillary lateral incisor, and second premolar
anodontia partial or complete
occurs in the initiation stage; development of one of more extra teeth that are commonly found between the permanent maxillary central incisors(mesiodens), distal to third molar(distomolar), and premolar region(perimolar)
supernumerary tooth or teeth
occurs during bud stage; abnormally small or large teeth that commonly affects permanent maxillary lateral incisor and third molar with partial ___dontia
microdontia or macrodontia (partial or complete)
micro
occurs during cap stage; enamel organ invaginates into the dental papilla that commonly affects the permanent maxillary lateral incisor; deep lingual pit that may need endodontic therapy may be needed ( tooth within a tooth)
dens in dente
occurs within cap stage; tooth germ tries to divide and develops large single-rooted tooth within one pulp cavity and “twinning” commonly in crown of anteriors with correct number in the permanent or primary dentition
gemination
occurs during the cap stage; union of two adjacent tooth germs that result in large tooth pulp cavities with one fewer tooth in dentition and is more common in anteriors in primary dentition; etiological factors is pressure; leads to a broader, falsely macrodontic tooth similar to gemination
fusion
occurs during the cap stage; small, rounded enamel extensions forming extra cusps that is commonly found on permanent posteriors occlusal surface or anteriors lingual surfaces
tubercle
occurs during apposition and maturation stage; certain factors may interfere with the metabolic processes of the ameloblasts, resulting in this disorder of____; faulty enamel development from interference involving ameloblasts that result in enamel pitting (enamel hypoplasia) and/or intrinsic color changes(enamel hypocalcification) with possible changes in enamel thickness; dental fluorosis, nutritional deficiences, trauma, systemic infections
enamel dysplasia
occurs during the apposition and maturation stage; union of root structure of two or more teeth by cementum that commonly affects permanent maxillary molars; etiological factors include traumatic injury or crowding of teeth
concrescence
occurs in the apposition and maturation stage; enamel sphere on root–> misplaced ameloblasts can migrate to the surface of root, causing enamel to be abnormally formed over the cemental root surface; could be confused as calculus deposit on root and may prevent effective homecare
enamel pearl
occurs during apposition stage and maturation; a type of enamel dysplasia, results from a reduction in the quantity of enamel matrix ; teeth appear with pitting and grooves in enamel surface
enamel hypoplasia
enamel hypoplasia can be noted in the presence of _____ and _____, which is caused by a teratogen of syphilis
hutchinson incisors and mulberry molars
have a crown with a screwdriver shape that is wide cervically and narrow incisally with a notched incisal edge
hutchinson incisors
have enamel tubercles or extra extensions from the cusps on the occlusal surface
mulberry molars
occurs during apposition stage and maturation; this disturbance results in reduction of the quality of the enamel maturation; teeth more opaque, yellower, or even browner bc of intrinsic staining of enamel; white sparkle spot= turner spot/ tooth
enamel hypocalcification
occurs during apposition stage and maturation; a certain type of enamel dysplasia, can affect all teeth of both dentitions; the teeth have a very thin enamel that chips off or have no enamel at all–> crowns are yellow bc of dentin underneath
amelogenesis imperfecta
occurs during apposition stage and maturation; faulty development of dentin, can result from an interference with the metabolic processes of the odontoblasts during dentinogenesis
dentin dysplasia
occurs during apposition stage and maturation; type of dentin dysplasia, results in blue-gray or brown teeth with opalescent sheen; enamel chips off bc of lack of support by dentin
dentinogenesis imperfecta
occurs during root development; resulting in either distorted root or severe associated crown angulation in a formed tooth; caused by distortion of HERS
dilaceration
occurs during eruption process; a residue may form on newly erupted teeth of both dentitions that may leave the teeth extrinsically stained; green gray residue; consist of the fused tissue of the REE and oral epithelium as well as dental cuticle
nasmyth membrane
occurs during eruption process; an odontogenic cyst that forms from the REE, after the crown has completely formed and matured
dentigerous cyst
