Ch. 307 - Development and Developmental Anomalies of the Teeth Flashcards
Primary teeth form in dental crypts by ___ weeks of fetal life
12
The permanent 1st, 2nd, and 3rd molars arise from buds that develop at approximately __, ___, and ___
4 mos of gestation, 1 yr of age, 4-5 yr of age
Lay down an organic matrix that forms enamel
Ameloblast
Calcification of primary teeth begins at ___ and concludes at ___ with mineralization of the 2nd primary molars
3-4 months in utero; postnatally at approximately 12 months
Primary dentition: Earliest to calcify
Maxillary central incisor at 3-4 month in utero
Primary dentition: Last to calcify
Maxillary second molar at 6 months in utero
Permanent dentition: Earliest to erupt
Mandibular central incisor at 6-7 years
Permanent dentition: Last to erupt
Third molar at 17-21 years
Occurs when no tooth buds form as in ectodermal dysplasia or when there is a disturbance of a normal site of initiation (e.g. area of a palatal cleft)
Anodontia
Teeth that are most commonly absent
1) 3rd molars 2) Maxillary lateral incisors 3) Mandibular 2nd premolars
Occurs when the dental lamina produces more than the normal number of buds
Supernumerary teeth
MC location of supernumerary teeth
Between maxillary central incisors
2 teeth joined together
Twinning
Twinning is most often observed where
Mandibular incisors of the primary dentition
Twinning can result from 3 phenomena
1) Gemination 2) Fusion 3) Concrescence
Result of the division of 1 tooth germ to form a bifid crown on a single root with a common pulp canal
Gemination
Joining of incompletely developed teeth that, owing to pressure, trauma, or crowding, continue to develop as 1 tooth
Fusion
Single wide crown supported on 2 roots
Fusion
Attachment of the roots of closely approximated adjacent teeth by an excessive deposit of cementum
Concrescence
Type of twinning that is found most often in the maxillary molar region
Concrescence
Group of hereditary conditions that manifest in enamel defects of the primary and permanent teeth without evidence of systemic disorder
Amelogenesis imperfecta
Teeth are covered by only a thin layer of abnormally formed enamel through which yellow underlying dentin is seen
Amelogenesis imperfecta
T/F Susceptibility to caries is low in Amelogenesis Imperfecta
T
Main problem in amelogenesis imperfecta
Enamel is subject to destruction from abrasion
Management of amelogenesis imperfecta
Complete coverage of the crown for dentin protection, to reduce tooth sensitivity, and for improved appearance
Odontoblasts fail to differentiate normally resulting in poorly calcified dentin
Dentinogenesis imperfecta
Enamel-dentin junction is altered, causing enamel to break away
Dentinogenesis imperfecta
Opaque white patches or horizontal lines on the tooth
Hypocalcification
Pitting or areas devoid of enamel
Hypoplasia
Mottled enamel
Fluorosis
Fluorosis can result from systemic fluoride consumption ___ amount during enamel formation
> 0.05mg/kg/day
Fluorosis can be caused by
1) Residing in an area of high fluoride content of drinking water >2.0ppm 2) Swallowing excessive fluoridated toothpaste 3) Inappropriate fluoride prescriptions
Fluorosis presents clinically as
Inconspicuous white, lacy patches on the enamel to severe brownish discoloration and hypoplasia
Severe brownish discoloration and hypoplasia in severe fluorosis are usually seen with fluoride concentrations in the drinking water > ___
5.0ppm
Neonatal condition that can produce blue to black discoloration of the primary teeth
Hyperbilirubinemia
Produces red-brown discoloration of teeth
Porphyria
If administered during the period of enamel formation, this can result in brown-yellow discoloration and hypoplasia of enamel
Tetracyclines
Cause teeth to fluoresce under UV light
Tetracyclines
Period at risk for discoloration and hypoplasia due to tetracycline use
4 months of gestation to 7 years of life
Conditions associated with delayed eruption of the 20 primary teeth
1) Familial 2) Hypopituitarism 3) Hypothyroidism 4) Cleidocranial dysplasia 5) Trisomy 21
Premature loss of primary teeth is MCC by
Premature eruption of permanent teeth
If the entire dentition is advanced for age and sex, ___ or ___ should be considered
1) Precocious puberty 2) Hyperthyroidism
Natal teeth are observed in approx 1 in 2000 newborns in the position of the
Mandibular central incisors
Teeth that are present at birth
Natal teeth
Teeth that erupt in the 1st month of life
Neonatal teeth
Teeth whose attachment are limited to the gingival margin, with little root formation or bony support
Natal and neonatal teeth
T/F A radiograph can differentiate between a supernumerary and prematurely erupted primary tooth
T
T/F A family history of natal or premature eruption is present in affected children
T
Exfoliation failure occurs most commonly in what region
Mandibular incisor
