lectures 8 & 9 - molars and primary dentition Flashcards
when do 1st molars erupt
around 6 years
when do 2nd molars erupt
around 12 years
when do 3rd molars erupt
if they erupt, usually around 17-22 years
does anything come before the permanent molars
no
functions of molars
mastication
maintenance of vertical dimension of face
maintenance of arch continuity for proper alignment
support cheeks
how many developmental lobes do molars have
one developmental lobe per molar cusp
height of contour in molars
facial - cervical third
lingual - middle third
maxillary first molars
widest tooth buccolingually
often has a small 5th cusp called the cusp of carabelli
where is the cusp of carabelli located
mesiolingual margin
what is an arch trait for maxillary molars
oblique ridge
maxillary 1st molar roots
3 - MB, DB, L
furcation
area between roots where they divide from the trunk
how many root canals do maxillary 1st molars have
4, there are two in the MB root alone
also 4 pulp horns
how many cusps do maxillary 2nd molars have
4 - 3 large (MB, DB, and L) 1 small (DL often missing)
can be in tricuspid form with the loss of the DL cusp
how many roots do maxillary 2nd molars have
3 - MB, DB, and L
roots close together all confined within crown outline
roots get closer together the farther you go back in the mouth
how many root canals and pulp horns do maxillary 2nd molars have
4 root canals - MB has 2 alone
3-4 pulp horns depending on cusp number
what are tubercles
projection in enamel, all maxillary molars may have them
mandibular 1st molar traits
largest mesiodistal dimension in any tooth
5 cusps (MB, DB, and small D)
2 buccal grooves
no oblique ridge - two transverse ridges
lingual tilt of crown
characteristic of mandibular posterior teeth
what pattern is the central groove in mandibular 1st molars
zigzagged
how many roots do mandibular 1st molars have
2 roots - M and D
root bifurcate near cervical line (more likely to see furcation)
how many root canals and pulp horns do mandibular 1st molars have
3 root canals: 2 in mesial root
5 pulp horns, only tooth to have 5
mandibular 2nd molars characteristics
2 buccal cusps, 2 lingual cusps
lingual tilt of crown
3 fossa
one buccal grove, one lingual groove
mandibular 2nd molars occlusal surface
2 transverse rides like 1st molar
cross pattern
how many roots do mandibular 2nd molars have
2, less spread
how many root canals and pulp horns do mandibular 2nd molars have
3 root canals, 2 in mesial root
4 pulp horns, one for each cusp
pericoronitis
inflammation of the tissue around the teeth, very painful
operculum
flab of tissue on tooth
when are all primary teeth starting to calcify
18-20 weeks prenatally
first to erupt for primary teeth
mandibular central incisors (6 months)
second to erupt for primary teeth
other incisors (maxillary lateral incisors last)
third to erupt for primary teeth
first molars
forth to erupt for primary teeth
canines
fifth to erupt for primary teeth
second molars (at about 2 years)
functions of primary teeth
chewing
support for teeth and lips
necessary for formation of clear speech
critical for maintaining space
baby bottle syndrom
when a baby is put to bed with milk and it bathes the teeth to cause erosion
traits of all primary teeth
smaller in size than permanent with the same name
crowns appear to be squeezed at CEJ
relatively longer roots than crowns
whiter in color
fewer anomolies
what is the difference between a primary pulp chamber and a permanent pulp chamber
the primary is larger
primary max. central
wider MD than long ways
no mamelons
more prominent cingulum
single root
primary max. lateral
smaller than central
longer in length than width
incisal angles are more rounded
root is longer than crown
primary mand. centrals
similar to successor but smaller
prominent cingulum
primary mand. laterals
crown is wider and longer than central
incisal edge slopes distally
cingulum is more developed with a deeper lingual fossa
primary max. canines
considerable smaller than successor
sharper cusp tip when first erupted
root twice as long as crown
primary mand. canines
smaller than max. canines
smoother lingual surface
single root not as long as max.
primary molars
primary second molars resemble permanent first molars
primary max 1st molars
may resemble maxillary premolars
may have 3 or 4 cusps
maxillary 1st premolar replaces these teeth
primary max. 2nd molars
larger than primary max 1st molar
may have a cusp of carabelli
4 cusps
3 roots
oblique groove
primary mand. 1st molar
does not resemble any other tooth
4 cusps
2 roots
primary mand. 2nd molar
larger than 1st molar
closely resembles form of permanent mand. 1st molar
5 cusps
2 roots
