Lecture 8 Static Forces of Occlusion Flashcards
what are static factors of occlusion
characteristics shared by the teeth when they are stationary
what do alignment and occlusion of the dentition determine
-the tooth position
- intra-arch alignment
- inter arch alignment
what factors and forces determine the tooth position
-labiolingual alignment
- mesiodistal alignment
- vertical position
-muscles
-genetics
-habits
what muscles are involved in tooth position
cheeks,lips and tongue
- neutral zone
what do genetics determine about tooth position
size and shape of the arch and teeth ->available space
what maintains tooth position
- interproximal contacts
- occlusal contacts
what does mesial drift affect
alveolar bone and gingival fibers
what is intra arch tooth alignment
the relationship of the teeth to each other within the dental arch
what is the plane of occlusion defined as
plane that curves to fit the occlusal surfaces and incisial edges of all the teeth
describe the plane of occlusion
- not flat
- concave on the mandible
- convex on the maxilla
- teeth positioned in the arches at varying degrees of inclination
what is the angulation of the teeth determined by
the long axis of the tooth (crown and root)
what planes are there in angulation of the teeth
-sagittal plane
- frontal plane
describe the angulation of mandibular teeth in the sagital plane
- anterior teeth: labially inclined 20 degrees
- premolars: mesially inclined 6 degrees
- molars: mesially inclined 10-15 degrees
describe the angulation of the maxillary teeth in the sagittal plane
- anterior teeth: labially inclined- central incisor greatest at 28 degrees
-premolars: mesially inclined 9 degrees - molars: mesially inclined 12 degrees- crowns of the maxillary molars tilted distally and labially
describe the angulation of mandibular teeth in frontal plane
-anterior teeth: vertical inclination 0 degrees
- premolars: 1st premolar- labial inclination of 9 degrees. 2nd premolar- lingual inclination of 9 degrees
-molars: lingual inclination of 20 degrees
describe the angulation of maxillary teeth in the frontal plane
- anterior teeth: incisors: distal inclination 2-6 degrees. canine- mesial inclination of 17 degrees
-premolars: slight buccal inclination of 5 degrees - molars: buccal inclination of 20 degrees
what is the curve of spee
- antero posterior curvature of the occlusal plane
-concave in the mandible, convex in the maxilla
what is the curve of wilson
-medio lateral curvature of the occlusal plane
- concave in the mandible, convex in the maxilla
what is the net effect of angulation on posterior teeth
-when they occlude they are loaded axially
-designed to take heavy loads and support the occlusal vertical dimension
what is the net effect on angulation on anterior teeth
-when they occlude they are not loaded through their long axis
- not designed for loading
what is the occlusal table
the area defined by the cusp tips and the mesial and distal cups ridges/arms
occlusal table is _____% of the buccolingual width of the tooth
50-60%
what does the occlusal table facilitate
axial loading
what are the inclines of the occlusal table and describe each
-inner incline: inclines inside the buccal and lingual cusp ridges
- outer inclines: inclines outside the buccal and lingual cusp ridges