Mandibular Molars Flashcards
How many cusps and lobes do Mandibular 1st molars have ?
5 cusps , 5 lobes
How many cusps for the Mandibular 1st molars are visible from the Buccal ?
All 5 cusps ( Lingual cusps are taller and wider than the buccal cusps)
Which teeth have a lingual tilt?
Mandibular 1st molar, 2nd molar, and 2nd premolar
Mandibular 1st Molar cusp size order
- Mesiobuccal
- Distobuccal
- Distal
- Mesiolingual
- Distolingual
Which pit usually need restoration on the mandibular 1st molar?
Buccal Pit
which cusps are visible from the lingual ?
Mesiolingual
Distolinngual
Distobuccal
For the Mandibular 1st Molar which side has a longer root trunk ?
Lingual
Anatomical Crown
area of tooth covered with enamel
(change due to attrition/trauma)
Clinical Crown
amount of tooth exposed occlusal to the gingiva
(change due to gingival level, eruption,wear)
Anatomical Root
Area of tooth covered with cementum
(change due to root reabsorption cementum desposition or root amputation)
Clinical root
Amount of tooth embedded in the alveolar bone
(change due to giningivial level or eruption)
Which two types of teeth are most likely to be wider mesiodistally in lingual half vs the buccal half?
(Taper from lingual to buccal)
- Mandibular 2nd premolar (3 cusp type)
- Maxillary 1st Molars
Need to preserve transverse ridge on
Mandibular 1st Premolar
Need to preserve Oblique ridge on …
Maxillary 1st and Maxillary 2nd Molars
Due to missing teeth …
A person can close their mandible beyond what is normal.
this can lead to TMJ, muscle and joint pain
wher do the first year mandibular molars erupt? second ?
First molars-6 years
second molars- 12 years
All molars are wider ___________ than _________
wider Meisodistal than occlusocervical
Molars are the shortest teeth
occlusocerivical
All Molar crowns have a _____ to ____ taper
(_____ cusps are shorter than ____ cusps)
All molar crowns have a mesial to distal taper
Distal cusps are shorter than mesial cusps
All crowns have a buccal to lingual taper EXCEPT
Maxillary 1st molar with larger distolingual cusp
Mandiibular 2nd premolar molar with three cusps
Buccal Height of contour for molars
cervical (gingival) third
Lingual height of contour for molars are in
Middle third
_________ dimension is ________ than __________ dimension for Mandibular Molars
Mesiodistal Dimension is much wider than buccolingual dimension
Mandibular 1st Molars
Buccal Cusps:
Lingual Cusps:
Buccal cusps
- Mesiobuccal
- Distobuccal
- Distal
Lingual Cusps
- Mesiolingual
- Distolingual
Mandibular 2nd Molars
Buccal Cusps:
Lingual Cusps:
Buccal Cusps
- Mesiobuccal
- Distobuccal
Lingual Cusps
- Mesiolingual
- Distolingual
_______ are the shortest teeth occlusocervically
Mandibular molars are the shortest teeth occlusocervically
Mandibular Molars usually have _____ roots
Mandibular Molars usally 2 roots (Mesial and Distal)
- Vertical Dimension
teeth usually move mesially over time and continue to errupt over time so that they are constantly in contact
Max molar is wider____ than the _____
Max Molar is wider mesial than the distal
_______ wider in contact area than the ____ buccal contact
Lingual wider in contact area than Buccal contact
Clinical Note for Lingual tilt of crowns for mandibular molars
- Hold Bur aligned with long axis of crown
- Perpendicualr to occlusal surface
- If you don’t you can reach the pulp horns
For the mandibular molar the ___ cusps are taller than the ____ cusps
Mesial cusps are taller than distal cusps
( only mesial cusps are visible from the mesial )
Which cusps for the mandibular first molars are visible from the Mesial?
Mesialbuccal and Mesialingual cusps
(Because Mesial cusps are taller than the distal cusps)
For the mandibular molars which roots are visible from the mesial?
Only the mesial root
(Because it it much larger than the distal root)
______ tilt of all mandibular crowns
lingual
How many roots can you see from the Distal for Mandibular Molar ?
Distal Root (More Narrow)
Mesial Root
Mand 1st molar is wider in the _____ half than the ___
(coverges toward the ____)
Mand 1st Molar is wider in the buccal half than the lingual half
(converges toward the lingual)
Mandibular 1st molar cusp size from largest to smallest
- Mesiobuccal cusp
- Mesiolingual cusp= Distolingual cusp
- Distobuccal cusp
- Distal cusp
Devlopmental groove pattern for Mandibular 1st Molar
Y shape pattern
Mandibular 1st Molar
Each cusp has a definite__________, but note that none of them meet. So that means …….
triangular ridges
that means that the occlusal surface typically does not have transverse ridges.
Mandibular 1st, 2nd Molars have ___ Fossa
(Names)
Mandibular 1st Molars have 3 Fossa
- Central Fossa
- Mesial Triangular Fossa
- Distal Triangular Fossa
(densley fossa)
Pulp canals
Mandibular 1st and 2nd Molars
Mesial - 2 roots
Distal - 1 roots (large)
( 2 roots)
Mandibular 2nd Molars
Are narrower _______ and shorter _________ than that of a mandibular first molar
Are narrower mesiodistally and shorter occlusocervically than that of a mandibular first molar
From the buccal view for the mandibular 2nd molars how many cusps are visible ?
all four cusps are visible
(because the lingual cusps are taller than buccal cusps)
What cusp and groove is missing from the mandibular 2nd Molar ?
Distal cusp
Distobuccal Groove
What groove is on the Mand. 2nd on the buccal ?
Buccal groove
Mandibular 2nd Molars roots
are closer together
roots are more distally inclined than in 1st Molar
Outline of the Mand. 1st Molar shape?
Hexagonal Outline
Mand. 2nd Molars shape outline ?
Rectangular shape
Manibular 2nd molar converage toward
the distal
Mand. 2nd molars are ____ than the Man 1st molars
Smaller than the Man 1st Molars
Mandibular 2nd Molars Cusps
(sizes)
- Mesiobuccal
- Distobuccal
- Mesiolingual
- Distolingual
(all cusps are equal size)
Mandibular 2nd Molars grooves:
Central groove
Buccal
Lingual
Developmental grooves form ____ shape on the mand 2nd molars
+ shape
Mand. 2nd Molars has triangular ridges that …
meet to form two transverse ridges
Mand 2nd Molar number of cusps and lobes
cusps: 4
Lobes: 4
Maxillary 1st Molar # cusps/lobes
Maxillary 2nd Molar # cusps/lobes
Maxillary 1st Molar: 4 or 5(Carabelli)
Maxillary 2nd Molar: 4 or 5(Carabelli)
Maxillary Molars are wider __________ than ___________
Faciolingual dimension than Mesiodistal dimension
Which cusps gets progressively smaller on the second and third maxillary molars ?
Distolingual Cusp
Maxillary Molars roots in their size ( greatest to smallest) ….
Lingual (Palatal) root
Mesiobuccal root
Distobuccal root
Maxillary 1st Molars from the buccal, how many roots are visible?
All three roots:
Distobuccal Root
Mesiobuccal Root
Palatal Root
what point do all three roots meet at from the buccal for the maxillary 1st molar?
Trifurcation
Maxillary 1st molar roots
converge
inclined distally
Which view can you see the trifurcation on the Max 1st Molar
Buccal only
(Lingual view, lingual root blocks it)
Cusp of Carabelli is found where?
Maxillary 1st molar
On the Mesiolingual cusp
From the Mesial view can you view the occlusal anatomy for the Maxillary 1st molar ?
No because the Mesial cusps are taller than the Distal cusp
Which roots are visible from the mesial for the maxillary 1st molar ?
Mesiobuccal Root + Lingual Root
Which roots are visible from the Distal for the Maxillary 1st Molar?
All three
- Lingual Root
- Mesiobuccal
- Distobuccal
From the Distal view for the Maxillary 1st Molar is the occlusal surface visible ?
Slightly visible
What shape does the Lingual root have ?
Banana shape
Maxillary 1st Molar cusp order (large to small)?
- Mesiolingual
- Mesiobuccal
- Distobuccal
- Distolingual
- 5th cusp
Maxillary 1st Molar shape ?
Rhomboidal Shape
For the obtuse and acute angles that the Maxillary 1st Molars make, which cusps make which angles ?
O: Mesiolingual + Distobuccal cusps
A: Distolingual + Mesiobuccal cusps
Which cusps make the Primary cusp triangle in the Maxillary 1st Molars?
Mesiolingual Cusp
Mesiobuccal Cusp
Distobuccal Cusp
(Pulp chamber is located right bellow)
Which Molar has an Oblique Ridge ?
It’s on the Maxillary 1st and 2nd Molar
What makes the oblique ridge ?
Triangular Ridge of the Distobuccal cusp
+
Distal Cusp ridge of the Distolingual Cusp
How many fossa are on the Maxillary molars? Names?
4 Fossa
- Central Fossa
- Distal Fossa
- Mesial Triangular Fossa
- Distal Triangular Fossa
How many grooves are there in the maxillary molars ?
7
What groove seperates the triangular ridge and the distal cusp ridge on the maxillary molar?
Transverse groove of the oblique ridge
What are the centric stops for Maxillary 1st Molars ?
Central Foss (Distobuccal Cusp of Mand 1st Molar)
Mesial Marginal Ridge (Mesiobuccal Cusp of Mand 1st Molar)
what are the centric cusp (functional cusps) of the maxillary 1st Molar?
Distolingual Cusp
Mesiolingual Cusp
Compared to the maxillary 1st molar, the maxillary 2nd molar is ?
shorter occlusocervically
Longer root trunk
The point of trifurcation on the permanent maxillary first molar is situated closer to the cementoenamel junction than on the maxillary second molar.
True
How many cusps do Max 2nd molars have?
4 (no cusp of caraebelli)
what shape to do max 2nd molars have?
rhomboidal or heart shaped
(depending on the size of the distolingual cusp)
what is the dip in the heart for the max 2nd molars?
Buccal Groove
Maxillary 2nd Molar cusp size ( largest to smallest)
- Mesiolingual
- Mesiobuccal
- Distobuccal
- Distolingual
which cusps for the Max 2nd molars make the primary cusp triangle?
Mesiolingual
Mesiobuccal
Distobuccal
Maxillary 2nd Molar centric stops
Central Fossa (Distobuccal cusp of Mandibular 2nd Molar)
Mesial Marginal Ridge (Mesiobuccal Cusp Mandibular 2nd Molar)
Maxillary 2nd molar centric cusps ( functional cusps)
Mesiolingual Cusp
Distolingual Cusp
Which tooth is most likey never to form ?
Maxillary 3rd Molar
Maxillary 1st and 2nd molar pulp
Mesiobuccal Root- two canals
Distobuccal Root- one canal
Lingual root- one canal
Max functional cusps
Mand functional cusps
Maxillary = Lingual Cusps
Mandibular = Buccal Cusps
Where are centric cusps located?
Positioned approximately 1/3 into the total buccolingual dimension
Contact occurs on outer and inner inclines of the cusp
Non centric Cusps
Maxillary
Mandibular
Maxillary= Buccal Cusps
Mandibular= Lingual Cusps
Non- Centric Cusps
provides the mandible stability in occlusion
interlocks the fuctional cusps
Non centric cusps are postioned
1/6 into the total buccolingual dimension
Inner incline of non-centric cusp functional significance
contacts with or is close to a small portion of the outer aspect of the opposing centric cusp
another name for non-centric cusps
guiding cusps
Outside occluding area (opposes embrasures)
another name for centric cusps
supporting cusps
supporting forces of occlusion
(Contacts Cental Fossa, Marginal Riges )
Normal occlusion
(Cusps)
- Mandibular Buccal Cusps occlude in the Central Fossa and Marginal Ridges of Maxillary teeth
- Maxillary Lingual Cusps occlude in the Central Fossa and Marginal Ridges of Mandibular teeth
Occlusal contact occurs from the centric cust from contacting
Opposing central groove
central fossa
marginal ridge and embrasure
lingual cusps of Mx premolars do not necessarily make contact marginal ridges but with
fossa of the opposing dentition
•Each tooth opposes 2 teeth in the opposite arch, EXCEPT
Mandibular Central Incisors
Maxillary 3rd Molars
Posterior Crossbite
Mandibular Lingual Cusp occlude in the Central Fossa of Maxillary Teeth
Maxillary Buccal Cusps occlude in the Central Fossa of Mandibular Teeth
Class I Occlusion
Mesial buccal cusp of the Max 1st molar in the Buccal groove of the mand first molar
Class II
The Mesial Buccal Cusp of Maxillary 1st molar is mesial to the buccal groove of the Mandibular 1st molar
Class III
The Mesial Buccal cusp of the Maxillary 1st Molar positioned Distal to the Buccal groove of the Mandibular 1st molar
What class is this?
Class I
what class is this?
Class II
What class is this ?
Class III
What class is this ?
Class II
Division 1
Excess Overjet
What class is this?
Class II
Division 2
Deep anterior bite with hooked or rabbited lateral incisors
Maloclussions can be a result of
skeletal misalignment or dental misalignment or both
Mx canine in
Labial embrasure btwn Md canine and 1st premolar
D cusp of Md 1st molar occludes in the
Distal Fossa of the max 1st molar
what is static occlusion?
how teeth contact when closing centric occlusion or centric relation
Dynamic Occlusion
how teeth relate to each other as the jaw moves out of centric postion (eccentric movement)
what is the red line?
curve of Monson
( 8 inch circle)
what is the curve of spee?
what is the curve of wilson?
What is the occlusal curve?
Eccentric Movements
Protrusive
Retrusive
Lateral Excursive
(movement away from max intercupation)
We don’t want teeth to contact
non-functional cusps
Canine Guidance
(cuspid rise)
Lateral Movements
- prevent non-functional cusps from colliding
- protects posterior teeth preveting fracturing of our cusps
(anterior teeth protect your posterior teeth posterior teeth protect your anterior teeth)
Anterior Guidance
Protrusive Movements
- Mechanoreceptors in anterior teeth (protection)
- Cause discclusion of the posterior teeth
Movement of the mandible to the right
right side=
left side=
right side= working side
left side= non-working/balancing side
Movement of the mandible to the left
left side=
right side=
left side= working side
right side= non-working/balancing side
as we move our jaw to the right….
the right side become the ____ side and the left side becomes the ___ nonworking side
working side condyle
left non working side condyle
Working side condyle:
Non-working side condyle:
Working side condyle: Rotates in the fossa
Non- working side condyle: Translates out of fossa down the articular eminence and moves medially
Side shift (Bennet Shift)
because our non-working side/ balancing side translates down the eminence and moves medially →side shift of both condyles
Interferences in a protrusive movements
- Distal inclines of Max lingual cusps against mesial inclines of mandibular fossae and marginal ridges
- Mesial inclines of the Mand Buccal cusps againt distal inclines of Max fossae and marginal ridges
undesirable protrusive interferences
Retrusive movement posterior contacts:
Mand. buccal cusps distal inclines with the mesial inclines of the max fossae and ridges
Retrusive movements for condyles move
upward and backward in the retrusive movement
eccentric movements take you out of
centric occlusion
Favorable working side contacts in laterotrusive movements
Outer inclines of the max lingual cusps w/ inner inclines of mand lingual cusp
Buccal to Buccal
(need sufficent canine guidance)
undesireable contact for the working side contacts
(lateral movements)
Outer incline of maxillary lingual to inner incline of mandibular lingual
(lingual to lingual)
Non- working arrow
Protrusive
working
non-working - red and at an angle
protrusive- blue and straight
working- green straight perp. to protrusive
which arrow is parallel to the oblique ridge?
non working movement
(red)
working movement is toward ____side that the mandible moves
same side
non working side is on the _____ side when compared to the movement of the mandible
opposite
all non-working side contacts are ….
(what are they)
undesireable
(max lingual contacting mand buccal)
if madible moves to the left, contact will be latertrusive while the right side will have
mediotrusive contacts
(identical but reversed)
Durring lateral movement the only teeth that contact are
canines via canine guidance or cuspid rise
(all teeth separate)
if there is no canine guidance then
develop excess wear, tmj, broken teeth cusps
what is happening at the condyle
lateral movement→working condyle→rotates →nonworking side translates down and medially
Bennett Shift- Working condyle has a lateral shift because non working side is moving medially
