Static Factors of Occlusion Flashcards
ALIGNMENT AND OCCLUSION
OF THE DENTITION (3)
►FACTORS AND FORCES THAT
DETERMINE THE TOOTH POSITION
►INTRA-ARCH ALIGNMENT
►INTER-ARCH ALIGNMENT
FACTORS AND FORCES THAT
DETERMINE THE TOOTH
POSITION (3)
►labiolingual alignment
►mesiodistral alignment
►vertical position
tooth posiiton (3)
muscles
genetic
habits
tooth position:
muscles (2)
- cheeks, lips, and tongue
- neutral zone
tooth position:
genetic
-size and shape of arch and teeth = available space
tooth posiiton (3)
muscles
genetic
habits
tooth posiiton (3)
muscles
genetic
habits
tooth posiiton (3)
muscles
genetic
habits
tooth position
inter proximal contacts (2)
- maintain tooth position
- mesial drift: alveolar bone nd gingival fibers
tooth position
occlusal contacts
-maintain tooth position
ALIGNMENT AND OCCLUSION
OF THE DENTITION (3)
- factors and forces that determine the tooth position
- intra arch alignment
- inter arch alignment
intra arch tooth alignment
the relationship of the teeth to each other within the dental arch
plane of occlusion
plane that curves to fit the occlusal surfaces and incisal edges of all the teeth
plane of occlusion
not
flat
plane of occlusion
teeth positioned in the arches at
varying degrees of inclination
plane of occlusion
- – on the mandible
- – on the maxilla
concave
convex
angulation of the teeth is deterred by the
long axis of the tooth (crown and root)
angulation of the tooth in the (2) plane
sagittal
frontal
ANGULATION OF MANDIBULAR TEETH SAGITAL PLANE anterior teeth: premolars: molars:
labially inclined (20 deg) medially inclined (6 deg) medially inclined (10-15 deg)
ANGULATION OF MAXILLARY TEETH SAGITTAL PLANE anterior teeth: premolars: molars:
labially inclined- central incisor greatest (28 deg) medially inclined (9 deg) medially inclined (13 deg)- crown of the maxillary molars are tilted distally (and labially)
ANGULATION OF MANDIBULAR TEETH FRONTAL PLANE anterior teeth: premolars: molars:
vertical inclination (0 deg)
1st pre- labial inclination (9 deg)
2nd pre- lingual inclination (9 deg)
lingual inclination (20 deg)
ANGULATION OF MAXILLARY TEETH FRONTAL PLANE anterior teeth: premolars: molars:
incisors: distal inclination (2-6 deg)
canines: mesial inclination (17 deg)
slight buccal inclination (5 deg)
buccal inclination (20 deg)
CURVE OF SPEE (2)
- antero-posterior curvature of the occlusal plane
- concave in the mandible, convex in the maxilla
CURVE OF WILSON (2)
- medio-lateral curvature of the occlusal plane
- concave in the mandible, convex in the maxilla
posterior teeth
when they occlude, they are loaded
axially
posterior teeth are designed to take
heavy loads,
support the occlusal vertical dimension
anterior teeth
when they occlude,
they are not loaded through their long axis
anterior teeth are not designed for
loading
occlusal table
the area defined by the cusp tips and the mesial and distal cusp ridges/arms
occlusal table is the –% of the buccolingual width of the tooth
50-60
occlusal table facilitates
axial loading
INNER INCLINES
inclines inside the buccal and lingual cusp ridges
OUTER INCLINES
inclines outside the buccal and lingual cusp ridges
alignment and occlusion of the dentition
forces and factors the determined he tooth position
- intraarch alignment
- inerarch alignment
NTER-ARCH TOOTH ALIGNMENT
THE RELATIONSHIP OF THE TEETH IN
ONE ARCH TO THOSE IN THE OTHER
ARCH
arch shape and size (2)
- u shaped/square/tapering
- symmettrical, smooth in outline
►ARCH WIDTH:
►ARCH LENGTH:
maxillary is wider
maxillary arch is longer
max: 128 mm long
mand: 126 mm long
NET EFFECT OF NORMAL ARCH
WIDTH (2)
- the buccal cusps of mandibular posterior teeth and the lingual cusps of maxillary posterior teeth occlude with the opposing central fossa areas
- minimize trauma to soft tissue
supporting/centric functional/stamp cusps
lingual cusps of max teeth and buccal cusps of mand teeth
guiding/non centric/balancing/shearing cusps
buccal cusps of max teeth and lingual cusps of mandibular teeth
BO line
imaginary line drawn through the buccal cusp tips of the mand teeth
LO line
imaginary line defined bt joining the lingual cusp tips of the max teeth
CF line
imaginary line that follows the central grooves and fossa of all the posterior teeth
the BO line of the mandible occludes in the
CF line of the max
the LO line of the max occludes in the
CF of the mand
cross bite (3)
the opposite of the ideal inter arch relationship
the BO line of the max occludes with the CF line of the mandible
the LO line fo the mand occludes with the CF line of the max
define the relationship between the
max and mandibular first molars
angles class 1 relationship is the
ideal occlusion from an orthodontic perspective
MB CUSP OF THE MAXILLARY FIRST MOLAR
is aligned directly over the buccal groove of the man first molar
MB CUSP OF THE MANDIBULAR FIRST MOLAR
occludes in the embrace area between the max second premolar and first molar
ML CUSP OF THE MAXILLARY FIRST MOLAR
occludes in the central fossa area of the mandibular first molar
MB CUSP OF THE MAXILLARY FIRST MOLAR
is situated over the embrasure between the mandibular second premolar and first molar
MB CUSP OF THE MANDIBULAR FIRST MOLAR
occludes in the central fossa of the max first molar
DL CUSP OF THE MAXILLARY FIRST MOLAR
occludes in central fossa of the mand first molar
MB CUSP OF THE MAXILLARY FIRST MOLAR
is situated over the embrasure between the mand first and second molar
DB CUSP OF THE MANDIBULAR FIRST MOLAR
occludes in the embrasure between distal marginal ridge of the max second premolar and the mesial marginal ridge of the max first molar
ML CUSP OF THE MAXILLARY FIRST MOLAR
is situated in the mesial pit of the mand second molar
VERTICAL OVERLAP (2)
- distance the max anterior teeth overlap the and anterior teeth in a vertical direction
- 2-4 mm is normal
HORIZONTAL OVERLAP (2)
distance the max anterior teeth overlap the mand teeth when measured in a horizontal direction
-2-4 mm is normal
CLASS II ANTERIOR TEETH
division 1
great vertical overlap, the man teeth contact the gingival third of the max anterior teeth (deep bite)
CLASS II ANTERIOR TEETH
division 2
max incisors are lingually inclined, laterals overlap the centrals labially
CLASS III ANTERIOR TOOTH RELATIOSHIP (2)
- end-to-end relationship
- mand anterior teeth are so far forward overlapping max anterior teeth