Occlusion of the molars - Minia
30
Occlusion of the molars
Transcript of Occlusion of the molars - Minia
Occlusion of the
molars
are *The maxillary molars
smaller mesiodistally than the
mandibular molars .
are *The maxillary molars
greater bucco-lingually than
the mandibular molars .
Generally: The maxillary molars*
bear
a disto-buccal relation to
the mandibular molars.
Upper first
molar , lying freeis The mesiobuccal cusp
buccal to the mesio-buccal groove
of 6
6
6 5
5
Buccal view
, lying freeis The disto buccal cusp
in the buccal embrasure of 6 and 7
cusp is The mesiolingualsituated in the center of the central fossa of 6 .
6
6
5
5
Lingual view
The distal marginal ridge
contacts the mesio-buccal
cusp of 7 .
ridge The mesial marginal
is distal to the mesial margin
of 6 .
7
is in The distolingual cusp
contact with the mesial
marginal ridge of 7 .
freeis The mesiobuccal cusp
and lies buccal to the buccal
groove of the 7 .
6 7
7 6
Upper Second Molar
freeis The distobuccal cusp
and lies within the buccal
embrasure of 7 and 8 .
The mesio lingual cusp lies
in the central fosse of 7
6 7
6 7
Lingual view
The distolingual cusp strikes the
distal ridge of the distolingual
cusp of 7 .
The distal marginal ridge is over
the mesial marginal ridge of 8
The mesial marginal ridge is in
contact with the mesiobuccal
cusps of 7 .
The mesiobuccal cusp is free
and its triangular ridge
resting in the buccal sulcus
of 8 .
The distobuccal cusp may be
its triangular ridge or free
contacts 8 on the disto-
buccal slope of its disto-
buccal cusp.
Upper Third
molar
The mesiolingual cusp rests in the central fossa of 8 .
If it has a disto-lingual cusp it strikes 8 on its distal marginal ridge.
Lingual view
The mesial outline lies distal to the mesial outline of the lower third molar.
The distal outline is at one line with the distal outline of the lower third molar.
The mesio buccal cusp contacts the distal marginal ridge of the 5 and the mesial marginal ridge of 6 .
Lower first molar
6
6
5
5 The distal cusp rests in the distal
triangular fossa of 6 .
The disto buccal cusp rests in
the central fossa of 6
The mesio lingual cusp is free of
contact and is located in the
lingual embrasure between the
5 & 6 .
5
6 5
6 The distolingual cusp is free and
is located immediately lingual
to the lingual developmental
groove of 6 .
The mesial portion of the
occlusal surface of 6 occludes
with the distal third of the
occlusal surface of 5 .
5
5
6
6
The distal marginal ridge lies
mesial to the distal marginal
ridge of 6 .
The mesiobuccal cusp contacts the marginal ridges of 6 & 7 .
The distobuccal cusp is centered in the central fossa of the 7 .
6
6 7
7
Lower second molar
The mesiolingual cusp is
free of contact and is
located in the lingual
embrasure of 6 & 7 .
6 7
6 7
The distolingual cusp is free of
contact and it is located lingual
to the lingual groove of the 7 .
The mesial marginal ridge is located mesial to the distal marginal ridge of 6 .
The distal marginal ridge is located mesial to the distal marginal ridge of 7 .
6 7
6 7
The mesio buccal cusp
contacts the mesial
triangular fossa of 8.
The disto buccal cusp rests in
the central fossa of 8
Lower third molar
8
8
The mesiolingual cusp is free of contact and
is located in the lingual embrasure of 6 & 7 .
The distolingual cusp is free of contact and it is
located lingual to the lingual groove of the 8 .
MMR lies with the DMR of 7
DMR lies at one line with the DMR of 8
Upper molars
, in the opposing B grooveFreeMBC
in the opposing embrassure FreeDBC
8……. DB slope of DBC of 8
central fossaMLC Opposing
DLC 6…….. MMR 7
7 ……..DR of DLC of 7
8 (if present) ……... DMR of 8
Lower molars
MBC: 6 DMR 5 7 DMR 6 8 M F 8
MMR 6 MMR 7
DBC: Central Fossa of the opposing tooth.
MLC: Free, Opposing Lingual embrassure.
DLC: Free, Opposing Lingual Groove.
cclusal relation of the 0Centric
deciduous teeth
A B
C D E
A B C D E
Established
at 3 years
The occlusal contact and
intercusp
Relations of all the teeth
during the Various
Functional mandibular
Movements
Protrusive occlusal relation
The mandibular arch bears a
forward relation to its centric
relation with the maxillary arch.
The process of biting or shearing
food material is performed by the
protrusive occlusal relation.
Retrusive Occlusal Relation
*It occurs by retrusion of the mandible.
*The mandibular teeth will have
posterior relation to centric occlusion
*Actually, retrusion is very limited and
non functional movement.
The masticatory cycle of anterior
teeth
In biting, the functioning side is located at the anterior teeth, while the balancing side at the posterior teeth.
During this action the incisal ridges of lower incisors are in contact with the lingual incisal thirds of the upper incisors, while the posterior teeth show anterior relation of the lower teeth to the upper teeth.
Right and left lateral occlusal
relation
In these movements, the mandibular dental arch
is placed in a right or left lateral relation to
centric occlusion with the maxillary arch.
L
B
RIGHT LEFT
Balancing side Working side
L B B
L B L
L
B
RIGHT LEFT
Balancing side Working side
L B B
L B L
L
B
L B B
L B L
The masticatory cycle of
posterior teeth
The masticatory cycle of
posterior teeth
of buccal cuspsshows the The working side
maxillary and mandibular teeth to be in contact.
lingual cusps of shows contact of The balancing side
of the maxillary teeth with the buccal cusps
mandibular teeth.
both sides move to centric occlusion and Then
alterations from one side to the other were
performed.
