Bimanual Manipulation for Capturing CR Flashcards
Bimanual manipulation will capture what?
locate and verify centric relation
three steps to bimanual manipulatoin
- relaxed muscles when the mandible is hinging
- PROGRESSIVE TMJ loading load the test joints to verify Centric Relation
- Evaluate centric relation relative to tooth contacts - taking a CR WAX RECORD
what is the response to immediate loading?
muscle bracing - which is undesirable
Step 1? hand placement initially? then what follows? what is the end goal result?
- Relaxed muscles when the mandible is hinging
Cradle the mandibular angles with the fingers and place the thumbs on the chin
THEN release the thumbs and ask patient to arc their mouth open and closed, about 1-2 inches - with the teeth slightly apart.
Goal - 9/10 the mandible will freely hinge
(if the muscles apppear to be tense on hinging, place a deprogrammer to relax teh muscles
we never load test the joints until…
The muscles are RELAXED and the mandible is FREELY hinging
Step 2? hand placement initially? then what follows? what is the end goal result?
Step 2: Load Test the joints to verify Centric Relation
While patient is hinging - dentist place thumbs on chin to begin to lightly torque the mandible
Then ask patient if they feel any sign of tension or tenderness
describe torquing
Torquing involves an equal pressure with the fingers wrapped around the angles of the mandible and the thumbs pressing DOWN AND FORWARD toward the chest
GOAL- to create a vector of force that is both superior and anterior within the joints bilaterally
asking if they feel Tension is aka
subtle way of asking whether the Lateral Pterygoid muscles is/are resisting full joint seating. creating positive awareness in front of the joints (extrascapular)
asking if they feel any tenderness aka
subtle way of asking whether there is any awareness of discomfort WITHIN the joints (intrascapular)
centric relation is only verified when…
the patient reports zero signs of tension or tenderness with light, moderate, and firm orthopedic load testing
how do you seat the joints?
with torquing
how to prevent getting out of synch with the patient?
Have the patient contiunue to make small hinge movements while you seat with torquing
hold it steadt while the patient makes small rotation movements
*it will prevent getting out of synch with the patient
Step 3? hand placement initially? then what follows? what is the end goal result?
Evaluate Centric Relation relative to tooth contacts
- once bimanual manipulation is verified through loading and pt. feedback with no discomfort - can begin evaluating occlusion
- Hold joints in centric relation - patient can close to the first point of tooth contact
- IDENTIFY the first tooth to contact– then the patient can squeeze their teeth together into the maximum intercuspation position.
- Observe if there is a CR/MIP discrepancy or slide.
* if yes note the direction and distance of the slide - DOCUMENT the first tooth cotact in CR, the distance and direction of the slide, and the teeth that touch in maximum intercuspation.
Centric Relation is
a maxilloandibular relationship at the JOINT LEVEL.
what does bimanual manipulation evaluate
the comfort and health of the fully seated joints
first step in analyzing occlusions?
Bimanual Manipulation
how to verify bimanual manipulation and once bimanual manipulation is verified?
verified through loading and patient feedback
- THEN you can proceed to check occlusion
important suggestion when ask patient to close to first point of contact
TOUCH LIGHTLY - so do not stimulate lateral pterygoid to reposition mandible if occlusal interferences are present
Once the first tooth contact in centric relation is identified….
patient can squeeze their teeth together into the maximum intercuspation position
Five Factors of Mandibular Movement
- Initiating Position (centric relation)
- Types of motion (rotation, translation)
- direction of motion/planes
- degree of movement
- clinical significance of movement
Centric Relation aka
CR or CRC
MOST SUPERIOR-ANTERIORLY musculo-skeletal stable position of the condyles bilaterally within the glenoid fossaw
TM Joints are in a state of health, tend to approximate this location repeatdly and reproducible with slightly separated (disclusion) and the muscles of masticationi are relaxed
Do teeth touch in CR?
NO - unrelated to tooth position
CR location compared to CO/MIP in the envelope?
CR is slightly more posterior and inferior than MIP
in sagittal view of posselt’s envelope of motion where is CR in relation to CO?
more posterio-inferior
when teeth are together the point goes up
describe anterior discal displacement?
reduction of joint means?
if the articular disc gets displaced from its normal position on top of the mandibular condyle
reduction = back to normal?
shape of disc and condylar head?
Disc = biconcave
Condyle = convex
Progressive TMJ loading
repeat the position while applying increased force to the mandible in a vector
deprogramming musculature? Part of which step in bimanual manipulaition?
in step one of relaxed muscles when the mandible is hinging (rotation only)
can do this with cotten
anterior deprogrammers DISCLUDE (separate) posterior teeth thereby decreasing the muscle tonus
“Romancing” the mandible? which step is it apart of?
HINGING * and is part of the first step with relaxing the muscles
Hands places in “cradling” the mandibular angles with the fingers and placing thumbs on the chin. Release thumbs and ask patient to arc mouth open and closed about 1 -1.5 inches with teeth slightly apart.
if muscles appear tense (tonus) on hinging, place deprogrammer to relax the muscles.
should relax muscles within a minute
how much should chair be reclined when going through bimanual manipulation?
about 45 degrees
who moves the mandible in step 1?
THE DENTIST
we never load test the joints until?
Muscles are relaxed and the mandible is freely hinging
step 2?
load test the joints to verify centric relation
step 3?
CREATING CR WAX RECORD– evaluating centric relation relative to tooth contacts
how to verify CR?
through the identification of the first tooth contact in CR
Wax perforation?
UNACCEPTABLE – as tooth contact will cause the mandible to go into MIP
five most common reasons for poor mandibular mounts?
- CR record is actually an excursive record
- incisal pin was not changed prior to mounting
- unlocked centric latch
- too much plaster
- was not stable (no stable cookie)
what wax did we use for capturing CR on partner? characteristics of it
DENAR bite registration wax
pre-fabricated for ease of use
malleable (soft) when warm
BRITTLE WHEN COLD
wide parts go towards molar
there is a space for a deprogrammer
factors related to Bite registration material selection?
- Accuracy
- Ease of Use
- Cost
bite leaf gauge
riveted shim stock - pre fabricated and is made of polyester strips in 1/10th mm increments.
used as an anterior deprogrammer (Dr. ferrio gave us one and it is blue) for taking CR records and also in equilibration procedures
bunny ears
another anterior deprogrammer
patient asked to ‘lightly touch/ hold deprogrammer?
must be lightly
- painless musculature and do not want tonus
anterior deprogrammer functions to decrease tonus in the masticatory muscles
anterior deprogrammers reduce muscle tonus in what muscles more specifically?
lateral and medial pterygoids
part of protrusive feature
major adjustable feature on our mark 320 articulator is?
Condylar inclination-
PROTRUSIVE movements – with adjustments made to condylar inclincations (0-60 degrees and we have ours pre set right now for entire semester to 30 degrees)
0= no inclination
protrusive records
USED WHEN WANT TO ADJUST CONDYLAR INCLINATIONS
used to set left and right condylar inclinations for various diagnostic and restorative dental procedures
eccentric record
are used to set other condylar positions for various other diagnostic and restorative procedures
incisal guide pin for mounting mandibular?
SET IT TO +5
- this will compensate for the wax and open the bow more
- if you forget to do this the pin will not reach the table
position of red support pin when mounting lower cast?
DO NOT RAISE IT
inaccurate CR records means?
innacurate lower cast mountings and inaccurate lower cast mountings will NOT enable correct occlusal anaylsis
