Development of the Dentition Flashcards
what is an overjet
distance between the upper and lower incisors in the horizontal plane.
what is the distance of a normal overjet
2-4mm
what is an overbite
vertical overlap of the upper and lower incisors when viewed anteriorly.
what is the distance of a normal bite
one third to one half coverage of the lower incisors
what is crowding
when there is insufficient space to accommodate the teeth in perfect alignment
what is hypodontia
congenital absence of one or more teeth
what is leeway space
difference in the mesio-distal diameter between c, d and e and 3, 5 and 5
what is a reverse overjet
the lower incisors lie anterior to upper incisors
what is a supernumerary tooth
an additioanl tooth to the normal series
what is malocclusion
variation from ideal occlusion which has dental health and psychosocial implications for the individual
what is ideal occlusion
anatomically perfect arrangement of the teeth
what is normal occlusion
acceptable variation from ideal occlusion
what is a lingual crossbite
the buccal cusps of the lower premolars and or molars occlude buccaly to the buccal cusps of the upper premolars and or molars
what are natal teeth
a tooth present at birth
what are neonatal teeth
teeth that erupt soon after birth
what is macrodont
an abnormally large tooth
what is transposition
a term used to describe the interchange in position of two teeth
what is BSI
incisor classification
what are the incisor classifications
class I
class II, division 1
class II, division 2
class III
describe incisor classification I
the lower incisor edges occlude with or lie immediately below the cingulum plataeu of the upper central incisors
describe incisor classification class II, div 1
- lower incisor edges lie posterior to the cingulum plataeu of the upper incisors
- upper central incisors are proclined of average inclindation, overjet is increased
class II, division 1
describe class II, div 2 of the incisor classification
lower incisal edges lie posterior to the cingulum plataeu of the upper incisors
upper central incisors are usually retroclined and the overjet is usually minimal but can be increased
class II, div 2
describe class III of incisal classification
lower incisor edges lie anterior to the cingulum plateau of the upper incisors
class III
what is orthodontics
branch of dentistry concerned with facial growth with development of the dentition and occlusion, and with the diagnosis, interception and treatment of occlusal anomalies
what are the main stages of dentition development
newborn
primary dentition
mixed dentition
permanent dentition
when does mixed dentition arise
6-13
describe the age range of permanent tooth eruption
between 6 and 13 years
which teeth are the first permanent teeth to erupt
first molars and incisors
when do first permanent molars erupt
6-8.5 years
when do permanent incisors erupt
6-8.5 years
anterior cross bite
increased overjet
reverse overjet
posterior buccal crossbite
what is mixed dentition
a mixture of primary and permanent teeth
when do canines, premolars and second molars erupt in mixed dentition
between 10 and 12.5 years
which permanent teeth erupt at 6
lower central incisors
upper molars
lower molars
which teeth erupt at seven years
upper central incisors
lower lateral incisors
which teeth erupt at eight years
upper laterals
which teeth erupt at eleven years
lower canines
upper first premolars
lower first premolars
which teeth erupt at 12 years
upper canines
upper second premolars
lower second premolars
upper and lower second molars
describe the eruption sequence of lower 3 4 and 5
3,4 then 5
describe the normal eruption sequence of upper 3, 4 and 5
4 5 and then 3
why does the posteior arch length increase
to accommodate the 6, 7 and 8
what does leeway space do
allow for lower incisors to align spontaneously following loss of d and e
what is the normal leeway space for the maxilla
1.5mm
what is the normal leeway space for the mandible
2.5mm
crowding
transposition
describe ideal molar occlusion
mesiobuccal cusp of the upper permanent molar occludes with the buccal groove on the mandible first molar
describe ideal incisal occlusion
slightly proclined so the lower incisal edge is in contact with the cingulum plateau of the maxillary teeth. the overjet and overbite 2-4mm on average
describe the dentition of newborns
usually there are no teeth
they have gum pads and an anterior open bite
describe the shape of the upper gum pad on newborns
rounded
describe the shape of the lower gum pad of newborns
u shaped
what is the classification of newborn jaws
skeletal class 2
describe what AP jaw relationship classifications are
skeletal class one
skeletal class two
skeletal class three
what is skeletal class one
where the mandible is 2-3mm posterior to the maxilla
what is skeletal class two
when the mandible is retruded relative to the maxilla
what is skeletal class three
when the mandible is protruded relative to the maxilla
skeletal class one
skeletal class three
skeletal class two
result of cleft palate correction surgery
when does primary dentition eruption first occur
6 months
what is the age range of eruption for primary dentition
6 month to three years
when do central incisors on primary dentition erupt
6-7 months
when do lateral incisors on primary denttion erupt
7-8 months
when do canines on primary dentition erupt
18-20 months
when do first molars erupt in primary dentition
12-15 months
when do second molars erupt in primary dentition
24-36 months
how can primary dentition be described
space
experiences wear toward the end
incisors are more upright than in permanent dentition
no spacing
66% crowding
less than 3mm spacing
50% crowding
between 3-6mm crowding
20% crowding
more than 6mm spacing
no crowding
how common is natal teeth
1 in 1000 infants
what is a unilateral cleft lip
a cleft affecting only one side of the lip
what is a bilateral cleft lip
a cleft affected both sides of the lip
what causes a cleft lip
failure of the lip and palate to unite during inter uterine development
when is surgery carried out on cleft lips
six months of age
what is an issue with repairing the cleft palate
scar tissue can cause contraction or restriction of growth of the maxillary dental arch
why do primary dentition experience wear near the end of their time
the enamel is softer and is not designed to last the individuals entire life
what is asymmetrical eruption
when tooth on one side erupts and the tooth on the other does not eg laterals
what is asequential eruption
when the laterals arise before the central incisors - improper sequence of eruption
