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Flashcards in occlusion (OB8) Deck (24):
1

what is occlusion

-contact between teeth - within arches and between arches (usually sit 2-5mm apart at rest):
->contact points
->arch form
->tooth alignment
->cross bites
->intercuspal position
->molar relationships
->incisor relationships

2

tooth contact (between adjacent teeth)

-contact point/ area: stagnation- caries risk
-contact point is critical for: food displacement during mastication onto grinding surface of tooth and arch alignment/stability (therefore it is important to restore a contact point, this can be done by matrix bonds)
->approximal contact = contact points are higher up on anterior teeth
->stagnation point is just below contact point
->contact areas are larger than contact points (on molars eg.)

3

arch form

-upper arch is longer than lower (has longer mesial-distal surface) and is slightly narrower at 8's (horse shoe shape)
-lower arch is slightly wider at the back (8's)
->therefore when arches sit on top of each other, the upper arch ideally sits outside the lower arch (upper buccal cusps are buccal to lower buccal cusps)

4

intercuspal position with ideal occlusion

-each upper tooth contacts with its lower antagonist and its distal neighbour (eg. upper 5 contacts with lower 5 and lower 6)

5

tooth alignment

-teeth do not sit perfectly vertically
-tooth alignment is determined by:
->path of eruption
->forces exerted on the teeth (by: teeth/as adjacent teeth push mesial teeth straight, soft tissues and other factors eg. thumbs or orthodontics = small forces over a long time)
-upper incisor teeth are inclined mesially
-upper premolars inclined bucally/ at an angle of 5degrees to the vertical axis
-upper molar occlusal surfaces face bucally/ at an angle of 20 degrees to the vertical axis
-lower molar occlusal surfaces face lingually

6

tooth alignment neutral zone

-neutral zone = zone of equilibrium between forces exerted on a tooth
-this is clinically important in denture construction

7

curve of wilson

-description of occlusal surface
-coronal/lateral curve
->upper teeth buccal surfaces pointing outwards
->lower teeth point inwards
-upper buccal cusps outside lower buccal cusps
->describes position of buccal cusps of upper and lower jaw in comparison to each other

8

bilateral cross-bite

-lower buccal cusps outside upper buccal cusps

9

unilateral cross-bite

-one side is in cross-bite (lower buccal cusps outside upper buccal cusps)
-other side is normal (upper buccal cusps buccal to lower buccal cusps)

10

curve of spee

-describes intercuspal position

11

angle's classification

-relationship between upper and lower 6's (first molar)
-6's are are key to the occlusion (as they are first posterior/often first permanent teeth that come through and have no deciduous predecessor)
-relationship between MB cusp of the upper 6 to the MB groove of the lower 6

12

class I angle's classification

MB cusp of upper 6 sits in MB groove of lower 6

13

class II angle's classification

-upper arch is relatively forward
-MB cusp of upper 6 sits anterior to MB groove of lower 6, DB cusp of upper 6 sits in MB groove of lower 6

14

class III angle's classification

-MB cusp of upper 6 sits behind MB groove of lower 6

15

overbite

-between tip of upper tooth and tip of lower tooth (area between upper incisor and lower inisor edge)
-tooth overlap in the VERTICAL plane

16

open bite

-type of overbite (tooth overlap in the vertical plane)
-however there is no overlap atall in an open bite
->sucking thumb etc can cause open bite

17

incisor relationships

-overbite
-openbite
-overjet
-reverse overjet
-incisor classification

18

overjet

-tooth overlap in the horizontal plane
->prominent upper incisors (sticking out)

19

reverse overjet

-due to more prominent mandible

20

incisor classification

-relates the lower incisor tip to the cingulum plateau of the upper incisor
->note that molar and incisor relationships may be different in patients

21

class I incisor classification

lower incisor tip sits in cingulum plateau of upper incisor

22

class II div I incisor classification

-lower incisor tip is behind cingulum plateau of upper incisor but still contacts upper incisor
->due to increased overjet

23

class II div II incisor classification

-retroclined upper incisors
-lower incisor tip sits behind the cingulum plateau of the upper incisor however there is no contact point between upper and lower incisor

24

class III incisor classification

-lower incisor tip sits infront of cingulum plateau of upper incisor
-> due to reversed overjet on normal occlusion