Primary teeth and chronology of tooth eruption Flashcards
ILO 8.5b: have knowledge of the form and function of teeth and associated structures, and the oral environment, in health and disease
what is a gingival cyst?
build up of keratin
developmental problem
what is a congenital epulis?
growth on mucosa on a newborn
what are natal/neonatal teeth?
teeth that are visable when baby is first born
what is an eruption cyst?
separation of teh dental follicle and crown of tooth leads to blood accumulating between the crown and gingiva
what notation do we use for deciduous teeth?
FDI notation: 5(UR), 6(UL), 7(LL), 8(LR)
when do teeth start to form?
week 5 of iul
when does hard tissue formation start?
week 13 of iul
how much of each deciduous tooth is calcified at birth?
6
central incisor: 1/2
lateral incisor: 1/3
canines: tip
first molars: 1/2
second molars: 1/3
first permanent molars: tip
what is a theory behinf tooth eruption?
4
resorption of the overlaying hard tissue
cellular proliferation at the apex of tooth
localised change in blood/hydrostatic pressure
metabolic activity within the PDL
how does resporption of the overlaying hard tissue occur?
enzymes in the dental follicle
how is the dental follicle involved in tooth eruption?
activated to initiate osteclastic activity in the alveolar bone ahead of the tooth and clear a path for tooth eruption
once crestal bone is breached, follicle likely to play lesser role
when is eruption of deciduous teeth complete?
2.5 - 3 years old
what is the order of deciduous tooth eruption?
ABDCE / 12435
lower before upper except lateral incisors
what are the second deciduous teeth to erupt and at what age?
lateral incisors 7-16 months
52, 62, 72, 82
what are the first deciduous teeth to erupt and at what age?
central incisors 4-6 months
51, 61, 71, 81
what are the third deciduous teeth to erupt and at what age?
first molar 13-19 months
54, 64, 74, 84
what are the fourth deciduous teeth to erupt and at what age?
canine 16-22 months
53, 63, 73, 83
what are the fifth deciduous teeth to erupt and at what age?
second molar 15-33 months
55, 65, 75, 85
what are the differences between primary and permanent crowns?
3
primary molars are wider mesiodistally
primary molar crowns are more bulbous
primary teeth usually whiter
what feature is present on an upper first molar?
prominent mesiobuccal tubercle
what feature is present on a lower first molar?
prominent mesiobuccal tubercle
what feature is present on a upper second molar?
transverse ridge
what feature is present on a lower second molar?
3 buccal cusps
what are the differences between primary and permanent roots?
2
primary teeth have narrower roots
roots of primary molars are longer, more slender adn flare apically
allows room for the developing permanent tooth crowns
what are the differences between primary and permanent pulps?
2
primary pulp chambers are large in proportion to the crowns
pulp horns of primary teeth extend high occlusally so are close to the enamel
what are the diferences between primary and permanent root canals?
1
primary roots canals are ribbon shaped with many interconnecting and accessory canals
clinically impossible to clean
what are the differences in primary and permanent hard tissues?
2
primary have thinner coronal dentine
primary have consistently thinner enamel
what are the differences in occlusal in primary and permanent teeth?
4
spacings
anterior spacing in primary dentition
anthropoid spacing: mesial to upper canine
primate spacing: distal to lower canine
leeway space: mesio-distal space occupied by primary molars
how long does it take for the completion of a root formation?
after date of eruption, takes 3 years for the permanent tooth root to complete apexogenesis
describe the eruption path of permanent incisors
permanent incisors develop palatal to primary incisors
