Facebow Flashcards
what is on the right side of the ear bow?
ANTERIOR REFERENCE POINTER will go up and down in vertical in order to align this to the point
metal in the holes
beveled
what do you need make sure the screw holes are…
PATENT - meaning unscrew enough
PATENT
can see the beveled edge
midline notch
located on the bitefork - so you can align it with the patients midline given by location of maxillary central incisors
where does the midline notch face?
ALWAYS SUPERIORLY - could use towards ceiling, faces incisal edges of the maxillary anteriors, upwards
what are the holes for in the bitefork?
RETENTION
what is the wax substituting?
PVS - these are expensive inject-able materials
TJA aka
transfer jig assembly
TJA parts
basically has three parts
1. vertical rod or shaft of transfer jog assembly
where does the vertical rod/ shaft go?
through hole number one on the TJA (transfer jig assembly)
parts of the vertical rod and how to adjust
screw to the right of it - has superior and inferior portions -
top and bottom cm of the vertical shaft/ rod
ARE BEVELED - flat side faces the patient
flat ends of vertical rod are placed?
towards the patient
what is hole number 2 for?
insertion point for the bitefork
which screw controls the bitfork
below the number two
- screw number 2
what goes on superior part of beveled rod?
Earbow
What goes on the inferior aspect of the beveled rod?
transfer jig incisal table
transfer jig table
replaces the white one that came with the articulator
- for the purpose of doing the transfer of the facebow of articulator of the MAXILLARY
- also has a beveled hole with screw that needs to be patent
which way does the thumb screw on the transfer jig table face?
YOU
where does the attachment screw on the transfer jig table face?
the floor
why are the screw holes beveled?
fit with the flat portions (that face the patient) on the vertical shaft/rod
where does the transfer jig incisal table go
onto the inferior aspect of the vertical rod /shaft
slope of the bitefork AKA
inclination or CANT of it
where is the patent open hole on the earbow?
underside of it
what attaches to the superior aspect of the rod
the beveled hole on the underside of the earbow
2 screws on ear bow and what they do
one tightens the ear buds that go into the internal acoustic meatus
the other tightens the ear bow to the superior aspect of the vertical rod
reference plane locator
the thin plastic ruler
anterior reference pointer
on the right side of the ear bow
- will go underneath the patients right eye
how many points in the maxillary spatial plane?
three
what are the maxillary spatial plane points
three
two of them are given by the location of the left and right external auditory meatus (opening of the left and right ear) - these are posterior
3rd = the anterior reference point
anterior reference point
part of the maxillary spatial plane and goes near the infraorbital part of the right eye ball - made with marker and the anterior reference plane locator
anterior reference pointer will align with what?
the anterior reference point - which is created with the anterior reference plane locator
to take ear bow off?
sequence
first release from patients ear - loosen the LARGE screw in the front
- retract pointer
- loosen the ear
- then screw IN FRONT to detach the ear bow from the rod
cleaning ear bow
cold sterile wipes
how does the bitefork go in and out?
IN - through posterior so the conical end will face you through hole number 2
OUT - loosen thumb screw beneath hole number 2
locating the anterior reference point of the spatial plane
anterior reference plane locator (ruler) and red marker
describe the reference plane locator
flat edge of notch / 90 degrees
pointy end - goes on the patients epidermis (skin)
what tooth and where does the reference plane locator go?
flat side/ 90 degrees with the incisal edge of tooth number 7 - MAXILLARY RIGHT LATERAL INCISOR
pointy part on the skin and put dot where this goes
dont have a maxillary right lateral incisor?
incisal embrasure between canine and central
what does the anterior reference plan locator approximate?
an average distance of 43 millimeters of the average location of an average healthy dentate adult from the incisal edge of tooth number 7 to area (superior/ above the incisal edge) and approximates the location of the infraorbital notch on the right
what does patient need to do when taking the anterior reference point?
NO SMILE - any distortion to the epidermis will also offset this mark
wax bitefork registration
what you take with the facebow apparatus and the TJA with bitefork assembeled
place wax in water bath T/F
true - at 160 degrees and gets soft
folding of wax
tri fold
take 1/3 and fold it onto itself
- place onto bitefork WITHOUT covering the notch and fold excess underneath
placement of bitefork
place in like alginate and push in then ask to bite down and pierce lips
temporalis and massater to tighten the bite
after put bitefork in
steps of setting up ear bow
- add the TJA with a preliminary tightening of screw two to hole two
- add the ear bow - attach to the superior rod by loosening screw 1 - locate external auditory meatus - then tighten
add the ear bow to the suprior aspect and tighten ear bow screw - loosen the right anterior reference pointer and align it
then tighten 1 and 2 screw when in line with the red dot
earbow is parallel to?
interpupillary line - if not skewed facebow
verticality of point is given by?
the anterior reference pointer on the right side of war bow
the lateralness of the accuracy of the three points on a plane is given by
given by screw number 2
to disassmble from patient?
- retract reference pointer and tighten
- loosen big round screw to loosen earbow
- grasp hole transfer jig assembly
once off the patient what should you do?
do a final tightening and HOLD FROM THE BOTTOM / TABLE
after take bite registration what do you have? *
relationship between bitefork and vertical shaft - anatomical spatial information of the patients maxillary spacial plane
attachment of the facebow is to what?
the LOWER BOW OF ARTICULATOR
plaster mount of cookie
for retention - have to smear the plaster in there
do you transfer with the ear bow?
no
Facebow transfer step
- loosen screw on underside of the transfer jig table - slide onto the lower bow
- add t-magnetic cast support
- align the upper cast to the bitefork
how to prevent movement of the bitefork when add weight of plaster?
T-shaped magnetic cast support - keep the rubber part at the bottom on - raise up the T until it reaches the underside of the bitefork and tighten both screws
does the cast need to be centered on the articulator
NO - this is a patients actual anatomical position and set up - so doesnt matter if it is not right underneath the cookie
slope of the arch?
ANTERIO-INFERIOR
technique for plaster
double plster mix technique with blob and smear vertical blob on the top of the cast engage notches with plaster move it around hand has not left upper bow
where must plaster go
into the undercuts of cookie
plaster mounting
filling notches and contouring
keeping pressure on upper bow
after first mixing
separate upper with plaster and cast from the bitefork and then separate the cast with cookie from the articulator - do not just pull - torque sideways - check if fill notches now do second mix to fill in any voids with fingers where needed - find notches especially then and make pretty with moist toothebrush and sand paper
1 most important tool to study and restore a patients occlusion?
A semi-adjustable articulator
advantages of articulator for diagnosis
Improves visualization of both static and functional tooth contacts (ability to see patients movements)
restorations fit occlusal requirements
less intraoral adjustments
what is our articulator called?
Mark 320 Semi-adjustable articulator
where is our artiulator adjustable?
adjustable in protrusive (0-60 degrees)
ADJUSTABLE CONDYLAR INCLINATION
- 30 degrees for entire year
- adjusting the left and right inclination of the condyles when they move in a protrusive – forward right and left
fixed (permanent) measurement on our articulator
FIXED INTERCONDYLAR DISTANCE
fixed bennet angle or side shift is permenately set to 15 degrees which is ‘average healthy human’ number
arcon articulators - guidance of the condylar movement in the _____ member
MAXILLARY
non arcon = mandibular
semi adjustable are only accurate for excursions if?
a facebow transfer is used
facebow transfer relates?
HINGE axis to maxilla
facebow registration
this registration relates the maxillary arch to the horizontal hinge axis of the patient
*in semi-adjustable the “ARBITRARY HINGE AXIS” is used – which is determined by the manufacturer of facebow and articulator system
average distance from ear to the hinge axis?
10-13 mm
arbitrary hinge axis
located with the help of the denar ruler
based upon the average location as determined by the manufacturer
