Final Flashcards
What type of movements does an articulator imitate?
MN!
Is an occlusal exam alone diagnostic of a disorder?
NO! NEED ARTICULATOR. Improve visualization of both static and functional interrelationships of teeth. Allows lingual examination of pts occlusion.
What are the types of articulators?
Non-adjustable, semi adjustable, fully adjustable.
What is the general rule of accuracy of articulators?
More adjustable, more accurate.
What did Bonwill do?
Equilateral triangle hypothesis. Arbitrary axis to orient casts. Apply theories of MN movement. Condyle centers for lateral, opening and closing.
Average Axis Facebow
A facebow that relates the MX teeth to the average location of the transverse horizontal axis.
What is an Ear Bow?
A face bow. Indexes to the external auditory meatus and registers the relation of the MX dental arch to the external auditory meatus and a horizontal reference plane. Used to transfer the MX cast to the articulator. Provides an avg anatomic dimension between the external auditory meatus and the transverse horizontal axis of the MN.
What is are the advantages and disadvantages of a non-adjustable articulator?
It is a “cast relator” Simple, inexpensive. But, limited accuracy in duplication of MN movements.
What are the advantages of a semi-adjustable articulator?
Allows 3 types of adjustments for more accurate reproduction of the condyles.
What are the 3 adjustments of a semi-adjustable articulator?
Condylar inclination, lateral translation movement (bennett angle) inter condylar distance.
What are the determinants of MN movement in a normal joint?
The farther anterior a tooth is located, the less influence the TMJ and greater the influence of the anterior guidance.
What do do lateral interocclusal record program?
Capture the exact position of the teeth and condyles during lateral movement. Condylar inclination and bennett angle are adjusted to duplicate this condylar position.
Condylar Inclination
Angle at which the condyle descends along the articular eminence.
Progressive (Bennett) Angle
The angle formed by the sagittal plane and the path of the non-working condyle during lateral movement of the MN as viewed in the horizontal plane.
Movement of the orbiting (non-working) condyle. Correct groove placement and fossa width.
Intercondylar Distance
The distance between the rotational centers of the condyles.
What does intercondylar distance effect?
Effects mediotrusive and laterotrusive pathways of posterior cusps over opposing occlusal surfaces.
What are the 3 points used to orient the MX cast?
Rt condyle, Lt condyle, anterior point.
Purpose of face bow?
Triangulates AP and laterally. Orients the MX cast in 3 dimensions to the articular using 3 pts. Rt condyle, Lt condyle and anterior pt.
What are the advantages and disadvantages of a fully adjustable articulator?
Advantages: Most precise condylar movement.
Disadvantages: Cost, time needed to properly adjust.
Semi vs. Fully adjustable condylar inclination
Semi is capable of producing a protrusive condylar movement in a straight line only. Fully is capable of duplicating the angle and curvature of the protrusive condylar movement.
Semi vs. fully orbiting condyle
Semi can record the progressive angle movement in a straight line only. Unable to reproduce any immediate lateral sideshift. Fully can duplicate the exact pathway taken by the condyle in laterotrusive movement and any immediate lateral side shift.
Semi vs. fully Rotating condyle?
Semi, no adjustment possible. Fully is capable of duplicating the lateral, superior, inferior, forward or backwards sideshift as the working condyle rotates.
Semi vs. Fully intercondylar distance
Semi has small, medium and large. Fully can exactly match the distance between condyles.
Immediate MN lateral translation
Bennett movement. It is the movement of the rotating (working) condyle. Influences fossa depth, cusp height, ridge and groove direction of posterior teeth.
What are the procedures required for the fully adjustable articulator?
Exact hinge axis location. Pantographic reading. CR record.
Pantographic recording
Identifies the exact MN movements. Protrusive and laterotrusive. Determined by pts condyles moving against the discs and fossae. Acts as face-bow transfer
The more adjustable an articulator is…..
Better accuracy, higher expense, more time transferring info from pt to articulator, less time adjusting intraorally, need to determine which articulator is right for treatment.
What do you use to select an articulator?
Characteristics of pts occlusion. Extent of the restorative procedures. Limitation of articulators. Skillz of the clinician.
When is a fully indicated?
Complex full mouth reconstruction. Cases with OVD changes of greater than 2 mm. NEED ADVANCED TRAINING.
MI
A closed contacting and static relationship of the teeth.
What is the total contacting area of teeth?
May not exceed 4 mm2
What provides consistency to occluding parts?
Elevations and depressions. Cusps and fossas. Ridges and grooves.
Determinants of occlusal morphology?
Recognized that patterns of occlusal surfaces are resultants of patterns of MN movement.
Is occlusion a primary factor in perio disease?
No! But it can be a severe secondary factor.
What does a proper occlusal analysis require?
Accurate diagnostic casts. CR mounting of the casts on a semi-adjustable articulator. Condyle controls set by lateral interocclusal records or by matching wear facets on teeth.
What are the cusp to fossa occlusion advantages?
Forces in line with the long axis of teeth. Eliminates the “plunger cusp” effect. Greater stability. Less tendency towards tooth mobility.
On the MX vs MN which way do the lines point?
Out on the MX in on the MN
What are the elevations?
Cusp tips, marginal ridges, triangular ridges, central ridges (buccal/lingual contours), supplemental ridges.
What are the depressions?
Supplemental grooves, developmental grooves, fossas.
What cusps are the stamp cusps?
Upper lingual and lower buccal.
What cusps are the shearing cusps?
Uppper buccal and lower lingual.
What is a unit of occlusion?
A cusp and a fossa.
What are the A contacts?
Non working cusps of the MX teeth occlude with the working cusps of the MN teeth.
What are the B contacts?
Working cusps of the MX teeth occlude with the working cusps of the MN teeth. Most difficult to attain and maintain.
What are the C contacts?
Working cusps of the MX teeth occlude with non-working cusps of MN teeth.
What is the exception to the ABC contacts?
Contacts on transverse marginal ridges.
What are the three equations that equal stability?
A+B
C+B
A+B+C
What happens with A+C?
MX teeth move buccally, MN teeth move lingually.
What happens with B only?
MX teeth move lingually, MN teeth move buccaly.
What are the purpose of closure stoppers?
Stop closure of MN as it relates to the MX. Neutralizes forces exerted by equalizers.
What are the locations of the closure stoppers?
Distal incline of MX posterior teeth and mesial inclines of MN posterior teeth. Close to summit of elevations, or protrusive excursions will abrade them.
What are the purpose of equalizers?
Equalizes forces exerted by closure stoppers, providing mesial-distal stability. To assure bucco-lingual stabilty.
What are the locations of the equilizers?
Mesial incline of MX posterior teeth and distal incline of MN posterior teeth. Should be more on the slope of the elevations, but can be on the summit.
Cusp movement
On MX non working is palatal. On MN non working is buccal.
What is selective grinding?
Precisely altering occlusal surfaces of the dentition to improve the overall contact pattern and fulfill treatment goals. MUST DO ON A DIAGNOSTIC CAST FIRST! Irreversible. Alterations must be within enamel. Doesn’t eliminate bruxism.
When do you use selective grinding?
Assist in management of TMD. Complement treatment associated with major occlusal changes (full mouth rehab/reconstruction, posterior FPDs, ortho.
Must have evidence that permanent alteration of an occlusal condition will reduce or eliminate symptoms associated with a specific TMD. Gained via reversible therapy.
What is the purpose of using an occlusal device before selective adjustment?
You need evidence the the occlusal device will eliminate the TMD symptoms before you adjust. If these positional changes alleviated the pt’s symptoms, then you are good to go.
What is the most common reason for selective adjustment?
Significant restoration or reorganization of the occlusal condition. FDPs, ortho.
When should SA be done when doing an FDP?
BEFORE the FDP. Provides a stable, functional MN position.
When should SA be done with ortho?
The final step of or immediately after completion of ortho treatment to aid in producing stable, functional MN position.
Is there any evidence that prophylatic adjustment benefits the pt?
No evidence.
What are the procedures that correct an occlusal discrepancy?
Selective adjustment, restorative procedures, ortho, orthognathic surgery. Choice based on amount of occlusal discrepancy when pt. is manipulated into CR.
What is the rule of thirds?
Based on buccolingual relationship of the MX and the MN teeth. Each inner incline of the posterior centric cusps is divided into 3 equal parts. The pt of contact between this inner incline of the posterior centric cusps and the opposing cusp determines the mode of treatment.
What treatment is indicated if the contact is on the 1/3 closest to central fossa?
Selective adjustment. Centric cusp is located on inner incline of opposing tooth closest to central fossa.
What treatment is indicated if the contact is on the middle 1/3 of the incline?
Fixed prosthetic procedures.
What treatment is indicated if the contact is on the 1/3 closest to the cusp tip?
Orthodontics and or orthognathic surgery.
How do you develop a plan for the equilibration?
Get info from diagnostically equilibrated casts. Identify initial CR contact and slide with interferences. Can anterior coupling be attained? Keep record of teeth and sequence in which they are adjusted. Know how far the incisal pin drops.
What are the two types of interferences that can occur during lateral movement?
Working side and non-working side.
Working side vs non working side
Moving away from the tongue-working. Moving towards the tongue-non working.
What is the first step in eliminating interference with lateral excursions?
Non-working side. Adjust the buccal inclines of the upper lingual cusps or the lingual inclines of the lower buccal cusps.
What is the second step in eliminating interference with lateral excursions?
Remove working side interferences. Adjust the interfering lingual surface of the upper buccal cusps and the buccal incline of the lower lingual cusps.
What are the three types of lateral guidance?
Canine, anterior teeth guidance, group function. Canine is most desirable as all posterior teeth are disoccluded and protected. If posterior teeth do contact in canine guided, they are a working interference.
Group funciton
Canines are not in a position to provide lateral guidance. Sometimes the premolars and even the mb cusp of the first molars guide. Ideally you don’t want the molar in there.
What is the third step?
Eliminating the interference with protrusive excursion. Only the front teeth should be in contact with the forces distributed evenly.
Where do posterior interferences during protrusive usually occur?
Distal inclines of the MX lingual cusps and the mesial inclines of the MN buccal cusps.
What are the three steps to adjusting?
Non-working, working, protrusive.
CR
Lateral
Protrusive
Re-check
What do you need to do after you complete all of the steps in adjusting the teeth?
Return to CR and check it.
Why do you need to recheck in 2-3 weeks?
The PDLs will heal from the occlusal trauma and tooth position may change.
What is the primary diagnosis?
The one that relates most closely to the pts chief complaint
What is the first step in treatment sequencing?
Medical and dental hx and listen carefully to their chief complaint in their own words.
2 reasons for permanent alteration of the occlusal condition?
Improve functional relationship between MX and MN teeth. TMD is second.
Steps of treatment planning.
Casts
Try reversible
Try irreversible on mounted casts
Pts approval
What is diagnostic waxing used for?
To predict the form and design of the fixed prosthodontic procedure.
Reversible occlusal therapy
Temporarily alters occlusal condition and or joint position. When removed, the original condition returns. Ex: occlusal device.
Irreversible occlusal therapy
Selective adjustment permanently alters occlusion. Original condition CANNOT return. Ortho, fixed pros, surgery, selective grinding.
How does occlusal condition influence chewing stroke?
Contact is relayed constantly to CNS. Stable occlusion should allow for effective functioning while minimizing damage to any components of the masticatory system?
What are the two ways TMD happens?
Acute changes in occlusal condition (altered sensory input) Orthopedic instability (plus loading)
Is occlusion always the cause of TMD?
NO! Different for every pt.
Indications of irreversible therapy
Improve functional relationship. Eliminate TMD. Restore masticatory function. Restoring dentition with operative procedures.
What are factors that influence treatment planning?
Symptoms, condition of the dentition, systemic health, aesthetics, finances.
Definitive treatment
Aimed at eliminating or altering the etiologic factors.
Microtrauma
Microtrauma is considered any sudden force to the joint that can result in structural alterations. Most common structural alteration is elongation of the discal ligaments.
Definitive treatment for trauma.
Reduce parafunctional activities. Establish a more favorable condyle-disk relationship that will unload the retrodiscal tissues and load the disc.
Definitive treatment for parafunction
Because diurnal activity can usually be brought to pts level of awareness it can be managed with education and cognitive awareness strategies. Restrictive use, voluntary avoidance, relaxation therapy, biofeedback.
Supportive therapy
Directed toward altering the pts symptoms and often has no effect on the etiology of the disorder.
Pharmacologic therapy
Analgesics: Opiates (moderate to severe pain, high abuse potential, codeine, morphine) Non-opiates (mild to moderate pain)
When are corticosteroids used?
Used rarely for acute, generalized muscle and joint inflammation associated with polyarthritides. (arthritic conditions in whic hthe articular surface of the joint is inflamed)
Do antidepressants help with chronic or acute pain?
Chronic. Improves quality of sleep.
When is local used in treatment of TMD?
Establish a correct diagnosis. Acute therapy. Breaking the pain cycle.
Thermotherapy
Uses heat to increase circulation (10-15 min)
Coolant therapy
(5-7 min) Encourages relaxation of muscles that are in a spasm. Vapocoolant spray or ice pack.
Ultrasound
Increases the temp at the interface of tissues, deeper penetration. Increases circulation and separates collagen fibers.
Phonophoresis
Administers drugs through the skin with the help of the ultrasound (hydrocortisone cream)
Transcutaneous Electrical Nerve Stimulation
Uses low voltage, low amp, biphasic current of varied frequencies to stimulate cutaneous nerve fibers. Electrical activity decreases pain perception.
Why can a gentle massage of the tissues overlying the painful area often reduce pain perception?
Soft tissue mobilization.
Joint mobilization
Decreases interarticular pressure and increases range of movement. Gentle distraction of the joint can assist in reducing temporary adhesions. Can be used to manage an acute dislocation without reduction. Should not be painful.
If joint mobilization is painful what should you thing?
Inflammatory joint disorder.
What is passive muscle stretching used for?
Reestablishing normal muscle length and function of painful shortened muscles. Open mouth slowly and deliberately until pain is felt.
What is assisted muscle stretching
Use gentle, intermittent force that is gradually increased. Vapocoolant spray reduces pain. Often after TMJ therapy, very useful to reduce adhesions or the capsular ligament fibrosing and tightening.
Resistance exercises
When opening mn depressors are active and elevator muscles relax slowly. If depressor muscle meets resistance, it sends a message to the elevators to relax more fully.
Postural training
Although there is evidence that cervical disorders are related, the exact relationship is not cure.
