Occlusal Curvatures and Angulations

Question 1

dental curvatures and angulations

Answer 1

the axes of the teeth are not at right angles to their masticatory surfaces
function: aid in dissipating the forces of mastication

Question 2

root axis line (RAL)

Answer 2

line representing long axis line of tooth, drawn to bisect cervical line

Question 3

axial inclination

Answer 3

a tilt in relation to the vertical axis
can tilt in two directions: mesiodistally and faciolingually

Question 4

root axis line function

Answer 4

blood and nerve supply
angle in the alveolar bone
curvature of the alveolar bone

Question 5

max and mand arch angles

Answer 5

maxillary arch is convex occlusally and mandibular arch is concave occlusally
when come into occlusion they align along anteroposterior and lateral curves

Question 6

curve of spee

Answer 6

anteroposterior curvature
curvature of the mand occlusal plane

Question 7

curve of wilson

Answer 7

lateral occlusal curvature
mandibular posterior crowns tilt lingually
maxillary posterior crowns tilt buccally
results from lower inward inclination of the lower posterior teeth

Question 8

attrition

Answer 8

tooth loss on the incisal/occlusal surfaces due to tooth-to-tooth contact
both enamel and dentin

Question 9

occlusal plane

Answer 9

imaginary plane formed by the occlusal/incisal surfaces of teeth when jaw is closed

Question 10

contact areas

Answer 10

the area where adjacent teeth in the same arch physically touch on the proximal surfaces
provide stability and protection

Question 11

contact areas: general rules

Answer 11

anterior to posterior… contact moves from incisal toward middle/cervical
the mesial contact is more incisal/occlusal than
size of contact area increases from anterior to posterior
proximal surface location is centered faciolingually (anterior), buccal of center (posterior)

Question 12

height of contour

Answer 12

greatest elevation of the tooth viewed from any surface
fattest/fullest area of perimeter of tooth

Question 13

height of contour general rules

Answer 13

facial height is the cervical third on all teeth
lingual height on anterior teeth is the cervical third; on posterior teeth is the middle third
proximal height on anterior teeth is incisal third; on posterior teeth is middle/cervical third

Question 14

interproximal spaces

Answer 14

area between adjacent tooth surfaces
normally filled with triangular soft tissue
space bound by: proximal surfaces of two teeth, contact area of the two teeth, alveolar bone

Question 15

why is the cervical third of any one tooth from the facial or lingual narrower than the incisal or occlusal third of the same tooth from the same perspective?

Answer 15

allows for:
-the interproximal space with attached gingiva
-room for alveolar bone
-stability

Question 16

embrasures

Answer 16

open space formed by curvatures of teeth next to contact

Question 17

types of embrasures

Answer 17

type 1- interdental papilla completely fills the embrasure
type 2- slight to moderate recession of the interdental papilla
type 3- extensive recession or complete loss of interdental papilla

Question 18

type 2 gingival embrasure

Answer 18

where gum disease usually starts, needs flossing, does not have any keratin

Question 19

embrasures general rules

Answer 19

viewed from facial or lingual, looking anterior to posterior: incisal/occlusals increase in size, cervicals decrease in size
viewed from incisal: labial and linguals are the same size
viewed from occlusal: lingual embrasure space is larger

Question 20

contact areas and embrasures

Answer 20

the size of the embrasure changes in relation to contacts/height of contour

Question 21

function of height of contour, embrasures and contact areas

Answer 21

form a spillway to direct food away from the gingiva
self-cleansing
protects gingiva but allows tissue stimulation
stabilize the teeth in the arch

Question 22

protection of the periodontium

Answer 22

contour of crowns, embrasure spaces, contact points

Question 23

over contoured restoration vs under contoured restoration

Answer 23

over: poor gingival stimulation, chronically inflamed
under: irritation and trauma

Question 24

depth of curvature

Answer 24

shape of CEJ, crown width, length, and contact areas

Question 25

depth of curvature general rules

Answer 25

facial and lingual: CEJ is convex towards apex
mesial and distal: cervical line is concave towards apex
proximal surface: greater on mesial than on distal
proximal surfaces of adjacent teeth: proximals that touch have the same depth of curvature
all surfaces of all teeth: depth of curvature greatest for central incisors, and decreases from anterior to posterior

Question 26

summarizing contacts, embrasures…

Answer 26

in the anterior:
-contacts are more incisal, and smaller
-gingival embrasures are larger
-depth of curvature (CEJ) is larger/more curved
as you move more posterior:
-contacts are more cervical, and larger
-gingival embrasures decrease in size
-depth of curvature (CEJ) decreases/less curved

Question 27

central groove

Answer 27

most prominent development groove on occlusal surface of the posteriors
travels mesiodistally
separates the occlusal table buccolingually
more efficient “food flow pattern”

Question 28

continuity of the central groove can be interrupted by

Answer 28

rotated or linguo-/labio-inclined teeth
under- or over-eruption of teeth
loss of teeth
mixed dentition or incomplete eruption of teeth

Question 29

marginal ridges

Answer 29

rounded raised borders on mesial and distal parts of the lingual surface of anteriors or occlusal table of posteriors
ideally at same level of height, affects embrasure forms

Question 30

marginal ridges: functionality

Answer 30

spillway
self-cleansing
gingiva more protected, more tissue stimulation
teeth more stabilized in arch