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143 Cards in this Set
- Front
- Back
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what are the 5 things teeth may be lost to?
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1. caries
2. periodontal disease 3. trauma 4. congenital defects 5. iatrogenic reasons |
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has the rate of partial edentulism increased or decreased?
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increased. thats why we are learning about it..
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Do all missing teeth require replacement?
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No
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why not??
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only where there is obvious oral dysfunction is it necessary to consider prosthetic replacement. A reduced dental arch is often acceptable especially if remaining teeth are likely to remain unstable
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clinical evaluation of the mouth should always include:
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1) size and shape of the residual ridges
2)structural and periodontal status of adjacent teeth 3)inter arch space 4) occlusion 5)esthetic expectations> |
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what are the 2 prosthodontic options?
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fixed partial denture
implant prosthesis removable dental prosthesis |
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what is the goal of prdp treatment?
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the replacement of missing teeth and supporting hard and soft tissues in a comfortable , functional , and esthetic manner.
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there are indications for removeable dental prosthesis, here are 5, what 2 are missing?
-edentulous space of more than 2 teeth -no abutment tooth posterior to the dental space -compromised perio support of potential abutment teeth -esthetics and function requiring extensive replacement of mucosal and osseous tissues -patient request |
- immediate replacement of extracted teeth
-patient unsuitable for oral implants |
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good oral hygiene can minimize what risk?
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plaque retention by extensive tissue coverage by prdp (tooth and gingiva)
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How long should you expect a prdp to last with good oral hygiene?
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8-10 yrs
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classification systems of the edentulous jaw can be based on support from?
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-teeth
-mucosa -teeth/mucosa |
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should classification precede dental extractions?
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no , they should follow
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if the third molar is present and considered an abutment, is it part of the classification?
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YES
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rigid bars , straps or plates that cross the midline to unite all other components of the PRDP without interfering with surrounding tissues. WHat is this?
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Major connector
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the minor connector usually crosses the tissues at _______
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right angles
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what support and retain and stabilize the prdp via the abutment teeth?
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clasp assemblies
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4 components of a clasp assembly?
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-guide plates
-rests -retentive arms of direct retainers -reciprocal or bracing arms |
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what do retentive arms do
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resist movement of the prdp away from the tissues
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these are rests that resist movement of the prdp away from the residual ridge when there is no distal abutment tooth
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indirect retainers
*class I and class II |
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what are the 5 components of a cast metal based RPD?
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-major connector
-minor connector -clasp assemblies -indirect retainers -denture base retention |
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the retromolar pads mark the distal extension of what classes of rpd?
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class I and class II
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what are the boundaries of the retromolar pad?
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temporalis posteriorly
buccinator laterally pterygomandibular raphe and superior constrictor medially |
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what is the equivalent of the retromolar pads in the maxilla?
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the tuberosities
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what overly the gap between the pterygoid hamulus and the tuberosities?
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hamular knotches
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most common anatomical variation in prdp?
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tori
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what major connector in the palate could u use to avoid tori?
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U shaped major connector
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where is prdp treatment classified in treatment phase?
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phase II (rehabilitation)
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what step comes before Making Facebow and interocclusal records to mount casts on articulator?
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Try rpd cast framework in the mouth
*altered cast impression if prdp is class I or II |
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what step comes after prescribing the PRdp framework?
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verify wax pattern framework prior to casting in chrome cobalt alloy
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what must you remember or the prdp framework?
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final cast must be duplicated to create a refractory cast on which the framework is created first in wax then in cast metal
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what do you need to do before you process the prdp in acrylic resin?
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try prdp with denture teeth set in wax in the mouth
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How do you maximize prdp comfort and wearability ?
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minimize prdp movement under function whilst preserving a patients original oral health and well being
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what is the rigidity of cast metal framework and acrylic resin necessary for?
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resist movement and distribute forces without distortion
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horizontal, and rotational axes of rotation about ______
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fulcrum lines
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the length of edentulous spans and lever force affect
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rotation
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resistance of movement towards the tissues
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support
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two components contributing to support?
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acrylic resin denture bases supported by ridge
occlusal or incisal rest seats on teeth |
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resistance of movement away from tissues?
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retention
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retentive arms and what other 2 components contribute to retention?
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proximal guiding surfaces frictional retention
adhesion/cohesion of denture base |
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resistance to lateral and rotational movement
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stability
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3 components of stability?
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1. denture bases
2.vertical surfaces of cast framework (rest, arms, cross arch stabilization, proximal plates) 3. occlusion |
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are over extended denture bases better for stability then?
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no, this will interfere with neuromuscular control
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what are 4 steps you must do BEFORE RECOMMENDING A PRDP TO A PATIENT?
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a. assess remaining teeth as abutments (stress)
b. occlusion (stress, clearance) c. articulated study casts (need record bases) d. existing prdp for clues |
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4 steps to microsurveying?
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1. analyze the poi in relation to favorable and unfavorable undercuts
2. select and mark the poi in lead or red pencil (SCRIBE) 3. mark in pencil the HOC of teeth 4. mark in pencil the HOC of soft tissue undercuts |
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what are the factors determining the tilt of the analyzing rod ?
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-appropriate guideplanes
-favorable and unfavorable undercuts -esthetics |
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what is the only part of the prdp framework that should be flexible?
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the retentive arm tip
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what is the metal component that engages the guide plane?
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guide plate
*mark outline with red pencil on cast |
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besides stabilizing clasp assembly, what should properly prepared guideplanes do?
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-guide prdp during placement and removal along the path of insertion
-improves stability and retention -reduce dead space that can trap food |
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a distal abutment tooth adjacent to distal extension base and a free standing abutment with both proximal surfaces in contact with prdp are considered what?
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elevated risk for overload. Therefore reduce the extent of the guideplane preparation on tooth or avoid preparing guideplane all together
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internal finish line
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where the metal meets the acrylic resin base.
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only after what two tasks can modifications to mouth tissues be made?
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after study casts have been articulated, surveyed and after prdp design has been determined
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step 1 for preprosthetic tooth modifications is occlusal adjustments. What are the following 3 in sequence?
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2. guideplanes for path of insertion and retention
3. changes to the heights of contour of teeth for retentive and reciprocal arms 4. rest seats-vertical support and cross arch stability |
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what are the dimensions of a rest seat on molars and premolars?
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1/2 distance between cusps. and 1/3rd the mesiodistal length. 1.5 mm deep
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what are the dimensions for a cingulum rest?
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~1.5 mm wide and 2-3mm long
semilunar shape |
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dimensions of incisal rest?
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1.5 mm deep and 1.5 mm wide
1.5 mm from gingival embrasure *appearance may not be acceptable! consider moving rests to mesial of premolars |
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what cast do you do occlusal adjustments, tooth recontouring and guideplanes, rests on?
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duplicate of study cast
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what is the purpose for a custom tray in prdp?
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-create a uniform thickness of impression material for greatest accuracy
-optimize border extensions -minimize material needed |
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how many layers of base plate wax is needed for an alginate impression on a custom tray?
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two layers of baseplate wax relief in order to provide sufficient tear strength of the alginate when set.
*PVS only requires one. |
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what happens to a class I or II if the retromolar pad is not captured in the custom tray?
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altered cast impression cannot be made properly if the retromolar pad is not shown on final cast bc the custom tray made on the framework will also be underextended
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how much coverage do you need for a custom tray on remaining teeth?
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only need to include 1mm of gingival coverage beyond teeth.
-maximize extension fully beyond edentulous areas tho!! |
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that component of a prdp used to resist vertical dislodgement along path of insertion consisting of clasp assembly or attachment?
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direct retainer
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7 basic requirements for clasp assembly?
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1. support from rigid rests
2. stability from guide plates and arms 3.retention from prox plates and retentive arms 4.reciprocation 5.encirclement by 1/2 of the circumference 6. passivity-only active on dislodging forces 7. occlusion-clasp assembly should not interfere with occlusion |
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retention provided by a retentive arm is influenced by 3 things.
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1. amount of undercut engaged
2.flexibility of retentive arm 3. type of clasp arm used |
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flexibility of the retentive clasp arm influenced by?
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length
cross sectional form (round is more flexible) diameter taper type of alloy |
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what has a higher modulus of elasticity? chromium alloys vs gold alloys?
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chromium alloys
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what if the retentive arm engages before the reciprocal arm on insertion of prdp?
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BRACING. the clasp assembly may only be passive once fully seated
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what is more important long term for retention- the proximal plate contact or retentive arm>?
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the proximal plate contact bc it is typically more durable
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reciprocal arm
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resists tipping force generated on the tooth as the retentive tip passes over the height of contour on insertion and removal of the prdp
-stabilizes the prdp from lateral movement |
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Types of Direct Retainers
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extracoronal
intracoronal |
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what type of extracoronal direct retainer is favored at ubc?
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suprabulge clasp assembly
-retentive arm approaches the undercut from above the HOC |
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what is a precision attachment?
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-an extracoronal retainer that is soldered or welded to cast restoration (NOT RECOMMENDED)
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Intracoronal retainers are for Kennedy class?
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III and IV (tooth supported)
*frictional retention *NOT RECOMMENDED |
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what can you do to a ring clasp for less food trapping and tissue trauma?
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plate the lingual surface
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3 components of a suprabulge clasp?
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shoulder
midsection terminus |
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if you must use an infrabulge clasp what will you use?
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I bar
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what are the 2 components of an infrabulge clasp?
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1. approach arm
.2. terminus (only part to contact tooth) |
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cast clasp optimal tapering at teeth?
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<1mm
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cast clasp
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preferred for kennedy III and IV.
chrome colbalt alloy cast as part of framework |
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ww clasps
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19 gauge
<1mm taper at tip soldered to framework preferred for I and II |
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when ww is with a cast allow reciprocal arm this is?
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combination clasp
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what are the benefits of cast clasp?
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simpler to fabricate
less likely to distort |
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what are the benefits of ww?
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more flexible and easier to adjust - less likely to fracture
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undercut preferred for cast clasp?
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.25mm
*.5 for ww |
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what is a proposed alternative to the combination clasp in clas I and II prdps?
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RPI class system
-rest -prox plate -I bar retentive arm |
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axes of rotation for prdps
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fulcrum lines
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where does the fulcrum line formed with occlusal load toward the ridge pass in I and II ?
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through the most posterior rests one on each side of the arch
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where is the retentive fulcrum line with displacing forces away from the ridge?
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passes through the tips of retentive clasp arms
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what are sticky foods resisted by?
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indirect retainer
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can a lingual plate be an indirect retainer?
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yes, only if it has a rest seat under it
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would you put the indirect retainer on the same or opposite side of the distal extension base?
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opposite side
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would you extend the major connector for indirect retention?
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no this is uneccessary
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how can the indirect retention "concept" be applied to class IV?
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no need for true indirect retention but direct retainers with rests are placed as far posterior as possible
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movement around fulcrum on rests during occlusal loading is minimized by what?
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well adapted distal extension base
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rigid
distributes forces no interference simple patient experience rounded smooth periphery |
the characteristics of a major and minor connectors
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mandibular major connector should clear the gingival margin by at least ____mm
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3mm
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the maxillary should clear the gingival margin by ____mm?
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6mm
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what are the preferred design features of a maxillary major connector at ubc?
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a bunch of ****. stay tuned on the next cards
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how does one reduce interference with speech and tongue function?
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minimize coverage of anterior half of the palate
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the anterior palatal strap should plate the lingual teeth or be avoided. otherwise a palatal strap should be ...
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crossing the midline no further forward than the mesial of the first molars
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where do you finish on the anterior palate if you must?
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valleys between rugae
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cross midline and gingival borders at ?
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right angles
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minimial width for palatal straps?
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8mm including plating
*posterior strap must be 2mm anterior to vibrating line |
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relief of palate?
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NO. score cast to create a beaded finish line (1mm depth)
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what do u think of the palatal bar as a ubc prodigy?
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IT SUCKS. bc this bar must be too thick to be tolerable
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which maxillary major connector is preferred for class I , II and III maxilla with no missing anterior teeth?
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palatal strap
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which connector is preferred for maxilla with anterior teeth missing or at risk for loss? (perio)
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AP strap. it is the most common major connector. Lingual plate the remaining teeth but be careful of spaces between the teeth
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if the max arch has a torus, what connector would you use?
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U-shaped horseshoe
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what is bad about the horseshoe?
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it is prone to distortion despite the minimal width being 15mm. it also can interfere with speech
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which connector is preferred for providing support if most teeth are missing or at risk for loss or the ridge is compromised or missing?
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palatal plate
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what should u consider with a palatal strap?
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using acrylic resin in place of some or all of the metal
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what are the preferred design features of mandibular major connectors at ubc?
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......just read on....
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you should extend the major connector on mandible from the ________ on one side to the _______on the other side
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terminal abutments
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the inferior border on the mandibular major connector is placed?
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at the functional vestibule of the floor of the mouth
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what does this inferior border require?
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lingual border molding and an impression of the functional vestibule with an adequately extended custom tray
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clear the gingival margin by?
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3mm to reduce trauma and plaque retention
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what do u need to prevent impingement with normal movement of the prdp?
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minimal relief space between the under surface of the major connector and the mucosa
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what mandibular major connector is preferred for most class I II III with no missing anterior teeth. There must be adequate height
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lingual bar
the height is 3mm (gingival margin clearance) + 5mm (bar height) to give 8mm. |
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the 5mm must be on what type of gingiva?
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ATTACHED, so watch the probing depths!
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what is the preferred major connector for mandibles with anterior teeth missing at risk of loss or when there is NO ADEQUATE HEIGHT. (<8mm total or <5mm of attached gingiva)
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linguoplate
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where does the linguoplate end on anterior and posterior teeth?
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just above the cingulum and height of contour
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if no rests are planned on the incisors of a linguoplate, then what do u do?
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place a rest at each end for support no further posterior than the first premolar (mesial if u can!)
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what is an alternative for mandibles with interproximal spaces between teeth (no plate) and there is no adequate height (no lingual bar)?
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sublingual bar
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how thick do minor connectors have to be?
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2mm thick
*at least 6mm between each or plate the tooth |
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what are the 4 types of denture base retention?
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mesh
RAP beading on metal surface braided post/nailhead on metal surface |
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what is denture base retention?
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a minor connector used to join the denture base and teeth to the major connector
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what denture base is preferred for missing adjacent teeth where ridge resorption has occurred or will
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Mesh -->most common
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what denture base is preferred for missing single teeth with a well healed ridge?
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braided post/nail head on metal surface
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what is preferred for missing maxillary anteriors with a well healed minimally resorbed ridge?
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RAP
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what is preferred for areas requiring acrylic resin for appearance but with minimal interarch space (<5mm)
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beading on metal surface
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what denture bases require relief?
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a space of 1mm is required for mesh and open web to accomodate processed acrylic resin except at tissue stop
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why do u need a 3mm by 3mm tissue stop on mesh and open web?
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to provide support during processing
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how is the tissue stop connected to the major connector?
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a 2mm wide strut extended through open web or mesh
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when do you need a step back?
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on class I and II prdps to provide adequate bulk for a smooth transition to the processed acrylic resin base
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where is the step back on max?
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anteriorly at acute angle from just short of hamular knotches
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where is the step back on mand?
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superiorly at acute angle from the distal abutment teeth
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What is included in the written details?
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rest seats
direct retention reciprocation indirect retention major connector denture base retention artificial teeth |
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the 7 responsibilities of a dentist with regards to working with laboratories
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1. provide lab with signed, written instructions
2. accurate impressions, casts, records 3.identify margins, post dam, borders, relief and design on all submitted cases 4. furnish a shade description, photo drawing or shade tab that closely achieves desires results 5.verbal or written approval for lab to proceed with fabrication if lab disagrees w instructions 6. retain your copy of prescription/written instructions 7. infection protocol |
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what can you examine on the existing rdp of a patient to help with your new design?
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the condition, design hygiene, fit function, esthetics
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For mandibular class I and II prdps, extend the inferior border of the framework to the border moulded floor of mouth EXCEPT?
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areas where an altered cast impression will be made
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what do you use for impression material of the opposing arch?
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alginate impression in stock tray
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purpose of altered cast technique (I and II)
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improve adaptation of denture base to ridge
improve contours of periphery equalize stress between ridge and abutments |
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altered cast technique is less necessary in the maxilla bc?
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there is major connector contact with the hard palate
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so what the heck is this altered pression technique all about???
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http://www.youtube.com/watch?v=pxIrmwM9ej8
good visual overview |
