tooth stages and disorders lecture 6

Question 1

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

Answer 1

initiation stage at week 6-7

Question 2

proliferation; growth of dental lamina into bud shape that penetrates growing ectomesenchyme

Answer 2

bud stage at week 8

Question 3

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

Answer 3

cap stage at ninth to tenth week

Question 4

proliferation, differentiation, morphogenesis; differentiation of enamel organ into bell shape with four cell types and dental papilla into two cell types

Answer 4

bell stage at eleventh to twelfth week

Question 5

induction, proliferation; dental tissue types secreted in successive layers as matrix

Answer 5

apposition stage at various times

Question 6

maturation; dental tissue types fully mineralize to mature form

Answer 6

maturation stage at various times

Question 7

occurs in the initiation stage; absence of permanent or primary teeth that commonly include permanent third molar, maxillary lateral incisor, and second premolar

Answer 7

anodontia partial or complete

Question 8

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)

Answer 8

supernumerary tooth or teeth

Question 9

occurs during bud stage; abnormally small or large teeth that commonly affects permanent maxillary lateral incisor and third molar with partial ___dontia

Answer 9

microdontia or macrodontia (partial or complete)

micro

Question 10

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)

Answer 10

dens in dente

Question 11

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

Answer 11

gemination

Question 12

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

Answer 12

fusion

Question 13

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

Answer 13

tubercle

Question 14

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

Answer 14

enamel dysplasia

Question 15

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

Answer 15

concrescence

Question 16

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

Answer 16

enamel pearl

Question 17

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

Answer 17

enamel hypoplasia

Question 18

enamel hypoplasia can be noted in the presence of _____ and _____, which is caused by a teratogen of syphilis

Answer 18

hutchinson incisors and mulberry molars

Question 19

have a crown with a screwdriver shape that is wide cervically and narrow incisally with a notched incisal edge

Answer 19

hutchinson incisors

Question 20

have enamel tubercles or extra extensions from the cusps on the occlusal surface

Answer 20

mulberry molars

Question 21

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

Answer 21

enamel hypocalcification

Question 22

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

Answer 22

amelogenesis imperfecta

Question 23

occurs during apposition stage and maturation; faulty development of dentin, can result from an interference with the metabolic processes of the odontoblasts during dentinogenesis

Answer 23

dentin dysplasia

Question 24

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

Answer 24

dentinogenesis imperfecta

Question 25

occurs during root development; resulting in either distorted root or severe associated crown angulation in a formed tooth; caused by distortion of HERS

Answer 25

dilaceration

Question 26

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

Answer 26

nasmyth membrane

Question 27

occurs during eruption process; an odontogenic cyst that forms from the REE, after the crown has completely formed and matured

Answer 27

dentigerous cyst