1/29: Maxillo-Mand Records Flashcards
What are the two maxillomandibular relationships?
Vertical and horizontal relationships
What are the two vertical relationships?
Occlusal vertical dimension (OVD), rest vertical dimension (RVD)
What are the 3 horizontal relationships?
Centric relation (CR), protrusive, R & L lateral (“eccentric”)
What is occlusal vertical dimension?
The distance between two points- one above and one below the mouth - measured when the occluding members are in contact
What is physiological rest position?
A postural position the mandible assumes when all muscles that close the jaws and all the muscles that open the jaws are in a state of minimal tonic contraction sufficient only to maintain posure
What exists between opening and closing muscles in physiologic rest poisition?
Equilibrium
At the physiologic rest position, there should be ______ contact of any teeth of one arch with teeth of the other arch
No
What is physiologic rest vertical dimension?
The distance between two selected points (one above, one below) measured when the mandible is in its physiologic rest position
What is the interocclusal distance (IOD) aka freeway space?
The space between the teeth or occluding members when the mandible is in the physiologic rest position
RVD = ______ + _______
RVD = OVD + Interocclusal distance (IOD)
What is the closest speaking space?
Closest relationship of the occlusal surfaces and incisal edges of the mandibular teeth to the maxillary teeth during function and rapid speech
- saying words with “S” in them– teeth shouldn’t touch
How to get the OVD?
- reference marks on nose and chin
- maxillary base/rim in mouth. Pnt says “M” and holds lips when first touch (is rest vertical dimension). Record the distance between the two reference points. Repeat and take average
- insert mandibular base/rim. Contour until meets max. rim evenly at approx 3 mm less than recorded RVD
What are examples of vertical relationships?
OVD, RVD, interocc. distance
What are examples of horizontal relationships?
Centric relation, protrusive, L&R lateral
What is centric relation?
Horizontal mandibular position at an established vertical dimension
Centric relation is what in relation to the mandible?
Centric relation is a reproducible posterior hinge position of the mandible
What are objectives of recording jaw relationships?
- Maxillary cast mounted to the correct axis by a facebow transfer
- Mandibular cast mounted in centric relation position to the max. cast
- Casts mounted at the correct vertical distance from each other to allow teeth to be arranged, bases placed in the mouth and teeth occlude at the vertical dimensions
When should the adhesive from the record bases be removed?
BEFORE placing the record bases on the master casts
*adhesive remaining will result in denture processing errors
What is the difference between the VDR and VDO known as?
Freeway space and is usually 2-4mm anteriorly
Making centric relation records consist of two phases:
- Getting the entire mandible retruded (bimanual technique)
- Positioning the condyle-disc assembly in the uppermost anterior position
What are factors that affect the centric relation?
- Resiliency of the tissues supporting the denture bases
- Stability and retention of record bases
- The tempro-mandibular joint and its neuromuscular mechanism
- Technique employed in making the records
- Amount of pressure applied in making the records
- The skill of the dentist
What is a facebow?
Instrument that carries the relationship between the maxilla and the condyles from the patient to the articulator
What are the two facebow types?
Arbitrary
Kinematic
What is an arbitrary facebow?
An arbitrary axis is used (external auditory meatus, etc)
What is a kinematic facebow?
The exact transverse hinge axis is located and used
Use arbitrary landmarks of the face/head to ___________ of the mandible
approximate the rotational centers
What does the kinematic facebow locate and transfer?
Locates exact hinge axis point on skin
Transfers cast to articulator in accurate relation to these points (not necessary for dentures)
What is the purpose of the facebow transfer?
To orient the maxillary cast to the articulator in the same relationship to the opening/closing axis of the articulator as exists between the maxilla and the opening/closing axis of the TM joints of the patient
What does a third point of reference transfer?
Elevation of cast in relation to the axis orbital plane of the patient
Facebow transfer should be used when:
- Cusp from posterior teeth are used
- Balanced occlusion in eccentric positions is desired
- Interocclusal records are sued to verify jaw positions/cast mountings
- The occlusal vertical dimension is subject to change
What does a semi-adjustable articulator accept?
Facebow records and interocclusal records
A semi-adjustable articulator has individually adjustable _______
Condylar guidances - vertical and horizontal
What kind of articulator is not needed for complete dentures?
Fully adjustable articulator
Denar, fully adjustable, not for denture fabrication are used for _______
Fixed
