PRS03 - Lecture 3 - Preliminary Jaw Registration Flashcards
What is the aim of preliminary jaw registration? (2)
Enable you to accurately study patients occlusion on articulator
Whilst designing their denture
What 2 things are you looking for with preliminary jaw registration?
Over-erupted teeth - if there’s room to fit an opposing tooth/baseplate
Interdigitation - is there room for denture components (i.e. rest seats, clasp arms)
What needs to be determined prior to carrying out preliminary jaw registration? (1)
If there is a position of maximum intercuspation or intercuspal position (ICP)
Describe the clinical steps of preliminary jaw registration (if there is ICP) (8)
1) Place the wax occlusal rim in the patients mouth
2) Trim until you reach natural occlusal (tooth-tooth) contact
3) You need to do upper and lower arches separately
4) Then place both wax rims in patients mouth simultaneously
5) Again - trim until you reach natural occlusal (tooth-tooth) contact
6) Cut grooves in the rims with a wax knife
7) Vesline patients lips and ensure clothes are well covered
8) Record position of maximum ICP using ZOE paste or softened wax
What position is preliminary jaw registration recorded at if there is no maximum ICP? (3)
Record the retruded position
Which is the relationship of the mandible to the maxilla - when the mandible is in its most retruded position
This position is used because its reproducible
Describe the clinical steps of preliminary jaw registration with a patient with no ICP (natural tooth-tooth contact)? (7)
1) Sit the patient upright with their head unsupported
2) Measure the patients rest vertical dimension (RVD) - measurement of the face made between any 2 selected points (one above + one below the mouth - usually in midline) with minimum muscle influence
3) Using Willis bite gauge or pair of calipers
4) Determine occusal vertical dimension (OVD) - usually 2-4mm less than RVD
5) Trim the wax rims until you obtain the desired value for OVD
6) Take a record using ZOE or wax but in the retruded position
7) Disinfect (in preform 10mins)
What is freeway space (FWS)? (1)
RVD - OVD = freeway space
What determines whether you carry out jaw registration in intercuspal or retruded positions? (3)
Posterior teeth present -> ICP
Teeth present but cannot get an accurate ICP -> RCP
Freeway space but premolars or molars missing -> RCP
What prescription will be sent off to the labs?
Please use jaw registration to articulate the primary casts
What 2 things need to be done after sending preliminary jaw registration to the labs?
Survey models
Design denture
What is the function of a facebow? (4)
1) Three components - facebow fork, anterior locator, U-bow (locate the condyles)
2) Record spatial relationship between maxillary arch to TMJ
3) Transfers information -> articulator to improve accuracy of occlusal articulation
4) This allows you to:
Study movements of teeth (so restorations or rest seats do not cause defective contacts)
Alter vertical dimention (complete denture)
Pre-contact records can be taken in retruded or protruded jaw relationships (complete dentures)
