Differences btwn Natural & Denture occlusion
- Natural teeth are suspended in the bone by the PDL which acts as a shock absorber.
- Denture teeth are part of the denture base which rests on movable/ displaceable tissues
- Premature, deflective contacts between artificial teeth cause movement of the denture resulting in damage to the supporting tissues
Goals of Complete Denture Occlusion
- Limit trauma to the supporting structures
- Preserve remaining structures
- Enhance stability of the dentures
- Restore Esthetics, Speech and Mastication
Define balanced occlusion
- simultaneous contacting of maxillary and mandibular teeth in the R and
- L and in the anterior and posterior occlusal areas when the jaws are either in centric or eccentric relations
What tool is used to establish balanced occlusion?
What is the facebow record?
- Records the orientation of the maxilla to the terminal hinge axis.
- Provides same relative opening axis on the articulator as the mandible has to the TMJ
- Definition: orients the maxilla to the transverse axis of the mandible in three dimensions and allows the transfer of this orientation to the articulator.
What is the hinge axis?
- hypothetical line through the two mandibular condyles around which the mandible may rotate.
- True hinge: difficult to record, requires special armamentarium
- Arbitrary: extimated within 6mm of true
- earbows use external auditory meatus as arbitrary hing axis
What is the ideal wax rim contoured for?
- phonetics, esthetics, lip support and occlusal
- 1-2mm below lip line
- parallel to Camper's plane(inferior ala nose and superior tragus of ear
- parallel to interpupillary line
What is fox plane?
helps properly orient occlusal plane
Where is the 3rd point of reference for the Denar facebow?
43mm above lateral incisor
How is vertical dimension determined?
- vertical separation between arches
- length of face
- distance between 2 points 1 fixed(nose tip) and 1 movable (chin)
- maintained by occlusion of teeth (OVD: occlusal vertical dimension) or balanced tonic contraction of opening and closing muscles of mandibular movements (VDR: vert dimension of physiological rest position)
- vertical separation of the jaws when the opening & closing muscles of the mandible
- are at rest in tonic contraction.
- Length of the face when the mandible is in rest position.
- In the absence of pathosis the relation is fairly constant throughout life.
- The position can be accurately recorded and
- measured within acceptable limits.
- It is used to determine the occlusal
- vertical dimension.
What is free-way space?
VDR-OVD (range 2-4 mm)
What is the closest speaking space?
- -vertical dimension when the mandible and
- muscles involved are in physiologic function of speech.
- -The final test that we use to determine if the vertical dimension of occlusion that we have chosen is correct.
- -Measure OVD of existing denture and compare.
- s sounds count 60-70
What are consequences of inadequate interocclusal rest space?
- EXCESSIVE OVD
- -clicking of the teeth
- -facial distortion, tense strained appearance
- -difficulty closing lips
- -difficulty swallowing
- -soreness and discomfort under the denture
- -increased ridge resorption due to trauma
What are consequences of Excessive Interocclusal Rest Space
Excessive Interocclusal Rest Space= Inadequate OVD
- reduced interarch distance when the teeth are in occlusion
- -overclosure is potentially damaging to the TMJ
- -normal tongue space is limited
- -facial distortion, chin is closer to nose, commissure of the lips turns down , lips loose their fullness
- -muscles of facial expression loose
- their tonicity, face appears flabby
- -angular cheilitis is sometimes attributed to overclosure
occlusion of opposing teeth when the mandible is in centric relation. This may or may not coincide with maximum intercuspation.
maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective discs with the complex in the anterior-superior position against the slopes of the articular eminences
What is the difference btwn CO and CR
- Centric occlusion with teeth present is a tooth-to-tooth relation,whereas centric
- relation, is a static position, is a bone
- to bone relation.
What are 3 methods to capture centric records?
- 1. functional (chew in)
- 2. graphic( intra/extraoral tracings)
- 3. physiologic (interocclusal record) wax, impression compound, ZOE paste
What are the requirements for making CR record?
- 1. Record the horizontal relation of the mandible to the maxilla at the proper VDO.
- 2.Exert equal vertical pressure on the record base while making the record.
- 3.Avoid distortion of the record until the casts have been accurately mounted.
- 4.A record that cannot be repeated or verified is not acceptable.
What position is ideal for capturing centric relation record?
- retruded-bimanual technique
- condyle disc assembly in uppermost anterior position.
What is protrusive record?
movement the mandible and condyle is downward and forward. The angle of the slide varies from pt. to pt. and from side to side.
USED to record and set condylar inclinations
that the articulator can perform eccentric movements equivalent to the relative
- movements of the mandible to the maxillae.
- This makes it possible to arrange the teeth for complete dentures in
- balanced occlusion.
- The mandible must be protruded a minimum of 5-6 mm when making the record.