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125 Cards in this Set
- Front
- Back
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Cardinal rule: you have to have enough _____ to make the partial denture.
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Space
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What are the criteria to define a distal extension?
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○ If the first molar is there, there is no distal extension
○ If the first molar is missing and the second molar is there, there is no distal extension. ○ To have a distal extension, you must have all molars missing. ○ If the first molar is present, but the teeth distal to it are missing, we are NOT going to make a denture that replaces those teeth. Anything distal to a first molar is not an edentulous area. |
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The ___________ becomes your guide to the Kennedy classification.
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most distal edentulous area
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Which Kennedy classifications are considered REAL Partial Dentures?
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K1 & K2
○ A real partial denture is one that moves during function§ It will move from 1-3mm○ This will give you the most problems. |
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What Kennedy classifications arfe the tooth supported RPD?
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K3 & K4
○ The entire partial is supported by natural teeth They hardly has any movement at all |
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The tissue covering the distal extension area have a property called _______
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viscoelasticity
§ This means that there is an initial compression of the tissue, then a few minutes later, there is a second compression. |
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Compare different compressions in distal extension viscoelasticity
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The initial compression is the greatest, the second compression is less.
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Sometime, with loss of teeth, with closure, they have learned to close in a certain way. What is this called?
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acquired centric position
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If you close in centric and the jaw relaxes a little and you can slide forward a little. What is this position called?
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Long Centric
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What is the Primary support on the mandibular arch?
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Buccal shelf
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What is the Secondary support on the mandibular arch?
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Retromolar pad & Alveolar Ridge
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What is the Tertiary support on the mandibular arch?
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Incline plane of the lingual ridge
§ This will be one of the primary areas of pain the patient will experience with either a full denture or an RPD. |
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When you take and impression, where should you extend it to?
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hamular notch (aka pterygomaxillary notch)
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What is another term for diagnostic cast?
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Study cast
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What does the retromolar pad contribute to dentures?
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It provides SUPPORT
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When deciding to place clasps, you want to place them in a way to ___________________.
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distribute the forces
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What is the snowshoe effect?
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• The anterior ridge (both max and mand) will bear very little pressure
○ The posterior ridge can withstand the pressure placed on it due to the composition of the bone in that area. ○ In the posterior area, it is like a snowshoe (spreads out the pressure) |
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What are the two types of partial dentures?
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Cast
Non-Cast (temporary) |
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What might be a reason why someone doesn't want to use their RPD?
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When they bite down they may experience pain
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Which Major connector has a Half-pear shaped longitudinal section with the thinnest part around the teeth and the thickest part near the apex of the teeth?
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Lingual Bar
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What is the simplest mandibular connector and is the one of choice for the routine prosthesis which has no unusual requirements?
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Lingual Bar
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Can you use a lingual bar a few mm above a torus?
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If a bar is placed superior to a torus and the denture base settles even a slight amount , the lingual bar will descend into contact with the thin mucosal covering of the torus and the effect will be very painful!! (like a stabbing knife)
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How far apart should minor connectors be placed in a Combination Bar and Plate?
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5 mm apart
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Which major connector is half-pear shaped in CROSS SECTION?
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AP bar
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Which major connector is half-pear shaped in LONGITUDINAL SECTION?
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Lingual bar
(seems like should be cross section too, but what do I know) |
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T/F
Mandibular major connectors are form fitted |
False
○ Mandibular major connectors don't touch the tissue -- are not form-fitted |
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Which Major connectors are used to avoid Tori?
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AP Bar
Horseshoe (U shaped) {maybe lingual plate as well for the mandibular) |
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Where is the inferior border of the lingual bar in relationship to the gingival margin?
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6-7 mm below the gingival margin
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What is the width of the lingual bar?
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3 mm wide
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Which Maxillary Major Connector provides a snowshoe effect, when you want the maximum support for the partial denture?
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Full Palate
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What are the two most important qualities that a major connector must possess?
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Rigidity & Cross-arch stabilization
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Where do minor connectors span?
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Goes from the major connector to the terminus. You taper it to the rest seat.
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T/F
minor connectors must have taper |
TRUE
○ Usually wide at its base and goes to the terminus tapering slightly. § You taper it to the rest seat. § The rest seat can be on the occlusal or lingual surface of the tooth. § It MUST taper Starts out like a column (~2.5mm) and goes down to about 1.5mm |
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T/F
AP bar cannot extend part the hard palate. |
True
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What is the best viewing angle to see where the lower anteriors are in occlusion with the maxillary teeth?
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From the posterior of your model
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How do sinuses affect the supraerruption of maxillary teeth?
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Pressure from sinuses can push down on the roots
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T/F
an extension (to the facial?) of the major connector is the metal backing |
True
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T/F
You may maintain VDO with the RPD |
FALSE
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How thick is the lingual plate?
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1 mm
(end of major connector lecture) |
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T/F
The rest seat is part of the partial denture |
False
The rest is part of the partial denture Rest Seat: Area prepared on tooth that is going to support the RPD |
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If you crown the tooth (full coverage), what kind of contacts will you have?
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you are going to have metal-to-metal or metal-to-porcelain contact
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When you see the patient for an RPD what should you look at first?
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1. Age of patient
2. Number and Location of Restorations 3. Will they have enough space for the RPD |
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What kind of rests do castings have?
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Castings have intracoronal rests.
□ This means inside the crown. □ It is very difficult to make these because you have to make room for the metal on the inside and you have to remove enough of the abutment teeth to fit this stuff. You can't make the tooth too bulky. |
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What shape does an occlusal rest seat have when viewing from the occlusal surface?
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Rounded Triangle
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What shape does an occlusal rest seat have when viewing from the side?
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looks like a teaspoon (concave)
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What is the width and depth of an occlusal or incisal rest seat?
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2.5mm wide x 1.5mm deep
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T/F
Every clasp will have a rest area |
False, (kind of)
Exception: With a wrought iron partial, (temporary partial), we usually don't do rests with this. The temporary is usually made out of wire and acrylic. |
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How deep does Dr. Castellerin ADVISE that we go with rest seats?
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1 mm (1.5 mm for crowns)
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What should you use to measure your rest seat prep?
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#8 round bur
#6 round bur for premolars cleoid discoid |
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Where should rests be placed in order to redistribute forces?
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Rests placed to direct forces along long axis of abutment
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Cardinal Rule: your occlusion is dictated by the ______ teeth
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Natural teeth
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Approximately how thick is the mucosa/mucoperiosteum?
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2.0+ mm
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Approximately how thick is the periodontal membrane?
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0.25mm +/- 0.1mm
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How far does a Splint bar (Dolder bar) need to be relieved from the tissue?
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Relieved about 1-1.5 mm from the tissue
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What type of prosthesis can be used when bone is knocked out in an accident?
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Splint bar (Dolder Bar)
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T/F
A Splint bar (Dolder Bar) is strictly an external prosthesis |
False
The bar can also be internal with some clips |
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Which rests are the least desirable?
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Incisal Rests (right angle rests), because they are butt ugly and located far away from the center of rotation for the tooth.
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Which teeth are most likely to require an incisal (right angle) rest?
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Usually because a lingual rest preparation is impossible to make without perforating the enamel, these rests are found on mandibular cuspids
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What are the Anterior Lingual Rests?
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1. Ledge rest
2. Spoon rest 3. Inverted V-shaped ledge 4. Incisal rests (end of rest seat lecture) |
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What kind of instrument is the surveyor?
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• The surveyor is an aligning instrument.
○ Can also be called a paralleling instrument Helps relate 1, 2 or 3 teeth to one another. |
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What type of surveyor do we use?
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Ney Surveyor
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T/F
You should draw HOCL on the master cast |
False
○ Do not draw HOCL on the master cast!! The only marks on the master cast should be the tripod marks. |
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What mechanical propertie is possessed by the terminal 1/3 of the clasp arm?
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Flexible
§ Only the 1/3 that goes below the height of contour is retentive § It can be called a bracing arm in the upper 2/3rds. |
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What are the mechanical properties of the clasp arm in the middle 1/3?
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Limited Flexibility
§ Only the 1/3 that goes below the height of contour is retentive § It can be called a bracing arm in the upper 2/3rds. |
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What are the mechanical properties expressed in the base 1/3 of a clasp?
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Rigid
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What is the upper 2/3 of a clasp arm called?
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Bracing Arm
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Which part of the clasp is used for retention?
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Only the 1/3 that goes below the height of contour is retentive
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Where is the angle of cervical convergence?
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Between the analyzing rod and the tooth in the area Below the HOCL
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Which type of material is used for an undercut of 0.01 inches?
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Chrome cobalt alloys (not as flexible as gold)
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Which type of material is used for an undercut of 0.02 inches?
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Gold-clasp (is more flexible than chrome)
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Which type of material is used for an undercut of 0.03 inches?
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Wrought wire (or other flexible wire, like ortho wire)
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Which amount of undercut provides the most desireable force of removal or insertion for their respective material used?
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All three (0.01, 0.02, 0.03 inches) will give you the SAME force of removal or insertion
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Which type of clasp material should you use on a person who is susceptible to caries?
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On a person who's susceptible to caries, you should use a WROUGHT WIRE clasp that is round and has point contact
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What are four factors determined by surveying?
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1. Retentive undercuts
2. Interferences 3. Esthetic problems 4. Guiding plane surfaces |
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Which viewpoint are you looking at the surveyor from when performing basic tilts?
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Posterior aspect of the cast
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What are the 5 basic tilts used on the surveyor?
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1. Right lateral
2. Left lateral 3. Horizontal 4. Anterior 5. Posterior |
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If we do not tilt the surveyor table, what is the path of removal and insertion?
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the partial would go to place and be removed in a path approximately perpendicular to the occlusal plane of the teeth.
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If the cast is tilted anteriorly when surveyed, where is the path of insertion and removal?
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it will transverse a path from the rear downward and forward. When it is removed, it will travel in the opposite direction.
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Why should we Minimize the undercuts on other teeth or in soft tissue?
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make possible more advantageous positioning of rigid parts of the partial such as connecting bars or the base
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T/F
The path of insertion is always parallel to the surveyor spindle, when surverying |
True
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What is the second surveyor tool from the right?
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Parallel Block out
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What is the last surveyor tool?
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Tapered Blockout Tool
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What is the problem with lingual undercuts?
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• Undercuts in soft tissue areas which would interfere with the placement of rigid parts of the partial would be undesirable.
• Lingual undercuts. ○ We are worried about the undercuts of the mandible |
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What is the guide to lateral movements?
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Canine Guidance
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If you have dentures, what is the guide for the occlusion?
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Group function, by balancing the occlusion
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What is another term for clasp?
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Direct Retainer
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What are 4 things every clasp should have?**
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1. Retention Arm
2. Bracing Arm (Aka reciprocal arm)-This is always above the height of contour 3. Rest-Resists vertical forces-Resists the partial from being driven into the tissue-Support!! 4. Minimum of 180 degree encirclement |
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Where is the bracing/reciprocal arm always located?
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Always above the height of contour
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What are 2 components of the Precision system?
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Intracoronal and Extracoronal
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Where is the largest undercut found on Mandibular teeth?
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LINGUAL for mandibular teeth
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Where is the largest undercut found on maxillary teeth?
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Buccal for maxillary teeth
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Which clasps can be used for distal extensions?
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Back action
Wrought wire RPI bar These can be used on the K1 most distal teeth |
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What causes the need for indirect retention?
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A fulcrum line or line of rotation
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What type of mandibular major connector can provide indirect retention and minimize tipping?
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Lingual Plate
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What does indirect retention specifically address?
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1. Prevents lifting of the mandibular D.E.
2. Prevents dropping of the maxillary D.E. |
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What are some forms of indirect retention?
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1. rest area
2. minor connector 3. lingual plate 4. 3rd direct retainer 5. Ruggae support |
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What are the parts of the clasp?
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a) occlusal rest
b) body c) shoulders d) terminals e) clasp arms f) strut g) approach arm h) terminal |
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What are the functions of the occlusal rest?
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□ Supports the clasp and the partial against vertical downward forces.
□ Helps prevent food impingement between tooth and clasp. □ Also functions as a stabilizing element if it is positioned in a well prepared res on the tooth. □ May also act as an indirect retainer. |
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What is the junction of the arms, occlusal rest, and minor connector called?
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Body
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What are the functions of the body of a clasp?
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1. Connects the arms with the occlusal rest and the minor connector.
2. Helps to prevent food from being forced between tooth and clasp. |
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Which component is usually rigid, provides most of the bracing or stabilizing action against lateral forces?
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The shoulders
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What is the function of the clasp arms?
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To retain and stabilize the partial and to encircle the tooth
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T/F
One part of the terminal will be below the height of contour and the other part will be above the height of contour |
True
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What are the different types of construction that clasps may be dived based upon?
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1) Cast metal clasp
2) Wrought wire clasp 3) Combination clasp (cast and wrought wire) |
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What are the different terms for a suprabulge clasp?
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Circlet
Circumferential Aker's |
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What type of clasp is an RPA?
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Circumferential clasp
mesial Rest guiding Plane retentive Arm |
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Where does the retentive arm of a circlet type clasp approach from?
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It approaches the undercut from above the survey line. It is said to be a "pull" type clasp.
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What are the advantages of the circlet type clasp?
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1. Excellent bracing qualities.
2. Usually easier to design and construct. 3. Requires less metal to construct, and usually less metal is lost in finishing. 4. More easily repaired if broken. Easier to straighten if bent. 5. Less possibility of food collection under clasp. 6. The clasp body and shoulders help the occlusal rest to provide support. 7. Can be used conveniently with either a metal or an acrylic resin base. |
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What are the disadvantages of a circlet type clasp?
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1. More conductive to caries, because of greater tooth coverage.
2. It may be less esthetic in some cases. 3. The “pull” type retention is less effective than the “push” type of the bar clasp. 4. Possibilities of variation in design are limited. 5. It increases the circumference of the abutment tooth, which in effect adds to the load to be borne by the tooth. |
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What are different types of circlet clasps?
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1. Simple circlet (Aker's clasp, #1, circumferential)
2. Wrought wire clasp 3. Back action clasp 4. Embrasure clasp 5. Ring clasp 6. Half & half clasp (split clasp) |
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Why don't we use a C-clasp for distal extension abutment teeth?
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The rest seat would be on the distal, which would not give you the proper forces along the long axis. This is why you put the rest seat on the mesial for the distal abutment of distal extensions (like the back action clasp)
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What is significant about a Wrought Wire RPA?
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Has the same configuration as a circumferential clasp, but NO Rest Seat
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When is a wrought wire clasp used?
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Usually used when Abutment Teeth are somewhat Weakened or Peridontally involved.-You want a clasp that will hold the partial in the mouth but not put a lot of force on it-easy to take on and off over the abutment tooth.
□ A wrought wire clasp can be used for a distal extension abutment tooth. |
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Where is the rest seat for back action clasps placed on the premolar?
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mesial, due to the angulation of the tooth
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Which clasp is primarily used at distal abutment of distal extensions?
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Back action clasp
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Which clasp is primarily used at distal abutment of distal extensions?
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Back action clasp
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Which clasp is usually used in KII when the distal extension side needs a lot of support from the opposite side?
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Embrasure clasp
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What is the primary use for an embrasure clasp?
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Provides a splint--supports one tooth with another
(embrasure clasp is the extracoronal way to provide a splint; soldering two teeth together would be the intracoronal way) |
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What teeth can ring clasps be used on?
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Tipped MOLARs only
*lower molars tipped ML *upper molars tipped MB |
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What is significant about the rests on a ring clasp?
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There are two rest seats, both mesial and distal
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What direction do maxillary molars drift?
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Mesiobuccally
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What are the indications for a half & half (split) clasp?
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Isolated, Rotated, or Tipped PREMOLARS
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What are some other names for the Infrabulge clasp?
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RPI Bar
Vertical Projection Roach type clasp |
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How does the retentive arm of a bar type clasp approach the undercut?
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RPI approaches the undercut from below the survey line
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What type of clasp is a "push" type of clasp?
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RPI
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