Occlusal Curvatures and Angulations Flashcards
dental curvatures and angulations
the axes of the teeth are not at right angles to their masticatory surfaces
function: aid in dissipating the forces of mastication
root axis line (RAL)
line representing long axis line of tooth, drawn to bisect cervical line
axial inclination
a tilt in relation to the vertical axis
can tilt in two directions: mesiodistally and faciolingually
root axis line function
blood and nerve supply
angle in the alveolar bone
curvature of the alveolar bone
max and mand arch angles
maxillary arch is convex occlusally and mandibular arch is concave occlusally
when come into occlusion they align along anteroposterior and lateral curves
curve of spee
anteroposterior curvature
curvature of the mand occlusal plane
curve of wilson
lateral occlusal curvature
mandibular posterior crowns tilt lingually
maxillary posterior crowns tilt buccally
results from lower inward inclination of the lower posterior teeth
attrition
tooth loss on the incisal/occlusal surfaces due to tooth-to-tooth contact
both enamel and dentin
occlusal plane
imaginary plane formed by the occlusal/incisal surfaces of teeth when jaw is closed
contact areas
the area where adjacent teeth in the same arch physically touch on the proximal surfaces
provide stability and protection
contact areas: general rules
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)
height of contour
greatest elevation of the tooth viewed from any surface
fattest/fullest area of perimeter of tooth
height of contour general rules
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
interproximal spaces
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
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?
allows for:
-the interproximal space with attached gingiva
-room for alveolar bone
-stability
embrasures
open space formed by curvatures of teeth next to contact
types of embrasures
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
type 2 gingival embrasure
where gum disease usually starts, needs flossing, does not have any keratin
embrasures general rules
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
contact areas and embrasures
the size of the embrasure changes in relation to contacts/height of contour
function of height of contour, embrasures and contact areas
form a spillway to direct food away from the gingiva
self-cleansing
protects gingiva but allows tissue stimulation
stabilize the teeth in the arch
protection of the periodontium
contour of crowns, embrasure spaces, contact points
over contoured restoration vs under contoured restoration
over: poor gingival stimulation, chronically inflamed
under: irritation and trauma
depth of curvature
shape of CEJ, crown width, length, and contact areas
