Fixed pros Flashcards
What is an articulator?
A hinged mechanical device to which maxillary and mandibular casts are attached.
What is the aim of an articulator?
To reproduce as closely as possible the relationship of a patient’s maxilla to mandible in RCP or ICP.
- Some articulators allow relationship to be reproduced during opening arc and during lateral and protrusive jaw movements (functional movements).
2 reasons to use articulators?
- Diagnostic study casts during treatment planning.
- May facilitate laboratory technician appropriately shaped crowns, bridges and dentures with functional occlusal schemes.
4 types of articulator?
- Simple hinge.
- Average value.
- Semi adjustable.
- Fully adjustable.
Simple hinge?
plane line
average value?
freeplane.
define occlusion?
the way the maxillary and mandibular teeth come together.
What are the splints for bruxism called? Maxillary? Mandibular?
STABILIZATION splints.
- Maxillary: michigan splint.
- Mandibular: tanner appliance.
Simple hinge articulator (4)?
- Equivalent to holding casts in hands.
- Occlusal relationship only correct when casts are together.
- Opening arc is determined by hinge design and is the same for all casts mounted (different from that of patient).
- Lateral and excursive movements not possible.
Average value articulator (6)?
- Sufficiently accurate for reproducing ICP.
- Condylar incilnation is set by manufacturer and cannot be changed.
- Allow for some degree of protrusive and lateral movements.
- OK for posterior restorations where there is obvious guidance from OTHER teeth (ex. canines).
- Complete/ partial removable prostheses - balanced articulation.
- Movement of cast is NOT accurate to patient movement.
2 cases where an average value articulator may be used?
- OK for posterior restorations where there is obvious guidance from OTHER teeth (ex. canines).
- Complete removable prostheses - balanced occlusion.
3 things that can be adjusted and 1 that cannot be adjusted in semi- adjustable articulators?
- Adjustment of condylar inclination.
- Bennett movement.
- Bennet angle.
- Cannot adjust inter-condylar distance.
2 types of semi-adjustable articulators?
- Arcon (Denar).
- Non arcon (Dentatus).
What is an arcon articulator?
Condylar component is attached to the MANDIBULAR member of the articulator and glenoid fossa is attached to the MAXILLARY member.
What is a non-arcon articulator?
Condylar component is attached to the MAXILLARY component.
Is arcon or non arcon more anatomically correct?
Arcon (denar).
What are arcon articulators used for?
Fixed prostheses work.
What are non arcon articulators used for?
Removable prostheses.
What cases are semi-adjustable articulators used for (5)?
- Fixed prostheses (when group function and one of the teeth in group function will be part of the restoration).
- Multiple units (ex. involved in guidance).
- Re-organised occlusion (ex. increasing vertical dimension).
- Group function (teeth involved guide the mandible).
- Anterior guidance.
- Occlusal analysis.
2 things needed to mount maxillary and mandibular casts onto an articulator?
- Facebow registration.
- Interocclusal record.
Define terminal hinge axis
An axis through the centre of the head of both condyles when they are in the most POSTERIOR/ANTERIOR? and SUPERIOR UNSTRAINED position in the glenoid fossa.
Centric relation?
Maxillomandibular relationship INDEPENDENT OF TOOTH CONTACT in which the condyles articulate in the anterior superior position against the posterior slopes of the articular eminences - UNSTRAINED, PHYSIOLOGIC
What is the first tooth contact called when the mandible closes in the terminal hinge axis position?
Retruded contact position.
When would you use a simple hinge articulator as opposed to just holding the casts in your hand?
When there are unsupported posteriorly/anteriorly due to missing teeth. Would use WAX RECORD BLOCKS to achieve this.