Lecture 3- Nomenclature II Flashcards
Line angle
When two surfaces meet
Mesiolabial line angle
Where mesial and labial surfaces meet
How many line angles do anterior teeth have?
6
How many line angles do posterior teeth have?
8
Point angle
When three surfaces meet
How many point angles does each anterior tooth have?
4
How many points angles does each posterior teeth have?
4
Face of a tooth
The area on the facial surface of teeth that is bounded by the line angles and height of contour
Only area of a tooth that reflects light
face of a tooth
What can change the APPEARANCE of the size of a tooth?
Change in the position or contour of line angles control the appearance of the size of the tooth
Line angles have…
Dramatic effects on esthetics
Height of contour
The greatest amount of a curve, or greatest convexity or bulge, farthest from the root axis line
Where is the lingual height of contour found on anterior teeth?
On the cingulum, or on the cervical third
Where is the lingual height of contour found on posterior teeth?
Middle third
Where is the facial height of contour found for ALL teeth?
Cervical third
Function of the height of contour (1)
Forms contact area on proximal surfaces
Function of the height of contour (2)
Protects gingiva surrounding the root
Function of the height of contour (3)
Affects the final esthetics of the tooth
Over-contouring consequences
Under-stimulation deflects food from gingiva and results in under-stimulation of supporting tissue
Under-contouring consequences
Irritation of soft tissue
Correct contour
Adequate stimulation for supporting tissue, leads to healthy teeth (provides protection and adequate stimulation)
Height of lingual and facial height of contour
.5 mm
Occlusocervical location of proximal height of contour
Interproximal contacts are located progressively closer to the gingiva the more distal they are located from the midline
Faciolingual location of proximal height of contour
Proximal contacts are facial to the center of the tooth (lingual embrasure is larger than facial)