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243 Cards in this Set
- Front
- Back
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3 basic types of RPDs |
interim transitional treatment partial denture
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RPD indicated when age, health, lack of time precludes more definitive treatment |
interim partial denture
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which jaw position is an interim partial denture normally constructed |
MIP |
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normal components of interim RPD |
acrylic resin denture base acrylic resin artificial teeth |
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what is optional for an interim RPD |
retentive clasps in surveyed undercuts |
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consideration for an interim RPD design material when long wear is anticipated (i.e. preadolescent patient) |
cast metal denture base (better fit and improved hygiene) |
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what retentive clasp can be used if no udercuts can be surveyed |
ball clasps (need sufficient occlusal space thought) |
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wire type and guage used for retentive clasps in interim RPD |
WW 20 guage |
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first component of the interim RPD to be formed |
retentive clasps |
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what is done to the cast to ensure intimate contact of the artificial tooth and base with the edentulous ridge |
double thickness (2mm) |
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what are placed in the ridge lap portions of the artificial teeth to provide mechanical retention |
diatorics |
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why are slight undercuts in the cast not eliminated for the interim RPD |
they provide some retention |
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outline for maxillary interim RPD |
horseshoe major connector with acrylic resin contacting lingual surfaces of remaining teeth |
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denture base form for mandibular interim RPD |
lingual plating extending as far inferiorly as possible without encroaching on movable tissues |
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how far posteriorly should the interim RPD major connector extend when replacing anterior teeth |
at least the DL surface of the first molar |
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2 reasons to extend interim RPD to DL of first molar when replacing anterior teeth |
distribute forces generated by RPD stability against anterior tipping forces |
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what is the polymerization time for the interim RPD base |
20 psi for 20 min in a pressure pot with no pressure pot allow to cure in a monomer saturated environment |
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on interim RPD delivery, what is painted on the intaglio surface prior to initial placement |
pressure indicating paste |
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concern during interim RPD try in and how to avoid |
locking interim in as acrylic engages undercuts -->don't force interim on! |
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what are the occlusal goals of an interim RPD when replacing anterior teeth |
free from opposing contact in CR or MIP light contact in eccentric movements |
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what will occur if occlusal overloading of the prosthesis is present |
rapid alveolar bone loss |
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what can be incorporated into the interim RPD to avoid occlusal loading and what is the easiest method |
occlusal rests (bend WW to engage occlusal surfaces of at least 1 post tooth on each side of the arch with denture base end having many angles to engage denture resin) |
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what is required information for the patient when delivering the interim RPD |
transitional partial denture |
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when a transitional partial denture is planned for an extended period of time, the design will be cast metal, what design is indicated to adapt this cast metal framework to acrylic teeth as natural teeth are lost |
lingual plating of the teeth most likely to be lost |
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what is put on the lingual plate as a tooth is lost to facilitate the attachment of a denture tooth |
a retentive loop |
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how is an impresison made to create a transitional partial denture |
if RPD exists take alginate with RPD in, pic up the RPD in the alginate, block out the denture base portion, pour up entire impression in stone then recover the RPD |
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what preparation is done on the cast for a transitional partial denture for teeth to be removed |
cut out teeth even with surrounding gingival tissue. make simulated socket with centure 2mm deeper than periphery |
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2 ways to aide retention of denture teeth in the lingual plating of transitional partial dentures |
wire loops soldered to the framework perforations through framework plating |
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if a denture flange is not planned on a transitional partial denture, how are the teeth to be arranged |
butted to the ridge which is why the labial surface is scraped |
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how soon after placing the transitional partial denture immediately after extractions should the patient be seen |
24 hours |
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what is the recall for patients with a transitional partial denture |
not greater than 3 months |
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what is frequently present in a transitional partial denture patient indicating the need for increased recalls to avoid periodontal abscesses |
deep periodontal pockets |
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pathology that may result from prolonged interim or transitional denture wear in conjunction with inadequate oral hygiene |
marginal gingivitis |
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what tissues are grequent sites of inflammatory hyperplasia associated with interim or transitional partial denture wear |
palatal tissues |
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pathology associated with ill fitting connectors and poor oral hygiene |
papillary hyperplasia |
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commonly used to carry tissue conditioner to abused oral tissues |
treatment partial dentures |
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prolonged marginal gingivitis can lead to |
chronic periodontal disease |
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2 ways oral soft tissues will react to chronic irritation |
hyperplasia recession |
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2 common factors for hyperplastic tissues |
continuous prosthesis wear with no tissue rest period poor oral and prosthesis hygiene habits |
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hyperplastic response to the overextended border of a denture base |
epulis fissuratum |
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soft material applied to intaglio of complete or partial dentures to allow better distribution of forces over the dental arch |
tissue conditioner |
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how long will tissue conditioner last before it hardens and becomes itself an irritant |
approximately 1 week (change every 3-5 days) |
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2 components of tissue conditioner |
powdered acrylic polymer (ethyl methacrylate) liquid ethyl alcohol and aromatic ester |
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mechanism of action for tissue conditioner |
improved force distribution short term cushioning
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if constructing a treatment partial denture, what is placed on the cast in the areas requiring conditioning |
single layer of baseplate wax in area to be conditioned then fabricate the rest of denture as you would an interim |
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which surface of the treatment partial denture is polished to prevent plaque and debris accumulaiton |
cameo surface |
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cameo surface definition |
viewable portion of a removable denture prosthesis |
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what is done with the treatment partial denture when the tissue conditioner is initially placed and the treatment denture is initially seated in the patient's mouth |
light pressure to cause conditioner to flow and perform border molding movements |
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how long should the patient sit quietly for the gel stage of the conditioner to be reached |
4-5 minutes |
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what is placed on the cameo surface of the treatment partial denture to avoid tissue conditioner adhering to it |
separator |
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what is done if the areas of the denture base are exposed through the tissue conditioning material |
relieve those areas and add new conditioner |
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what is the best method to relieve show through areas of a denture base in the presence of surrounding conditioner and why |
coat with liquid soap, relieve the show through, was off soap (it prevents fragments from adhering to the conditioner) |
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is it permissible for the tissue conditioner to be allowed to dry? |
no, pt must be instructed when denture not in mouth it must be submerged in water |
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what are RPD wearers at increased risk for due to the requirement to keep the prosthesis out of the mouth for some time each day |
distortion and damage |
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relining |
adding new denture base material to the existing resin to make up for loss of tissue contact caused by resorption of the alveolar ridge. it can be done in a lab or chairside |
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what is the method of choice for relines |
laboratory reline |
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rebasing |
bulk of the denture base is removed and replaced using new resin |
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easiest means of evaluating the space under the denture base and its need for a reline |
place tin mix alginate in RPD base, place in mouth, allow to set |
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alginate mix for relining eval |
1 scoop powder plus 2 measures warm water |
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another means of evaluating support on distal extension RPD |
apply seating force on most posterior aspect of denture base and observe if indirect retainers unseat |
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what are the alginate measurements or the indirect retainer lift-distances that indicate a reline |
2mm alginate under base indirect retainer lifts 2mm or more |
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what is indicated if the existing RPD is short of ideal coverage of the denture bearing area: a rebase or reline |
rebase |
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2 reasons to remove uniform depth of denture base before taking a reline impression |
space for impression material so it doesn't displace ST eliminate potential contaminants and give good bonding surface |
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the more displaceable the tissue on the denture base area, the more or less space is required for impression material |
more space required |
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what impression material is indicated for mobile tissue on the crest of the ridge |
ZOE |
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impression materials indicated for dense, firm tissue on crest of ridge |
polysulfide rubber base polyether PVS mouth temperature wax |
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can tissue conditioning materials be used as impression materials for relining |
yes but they may displace tissues more |
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what is the most critical step in the reline process |
maintain tooth-framework relationship during the impression |
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once the impression material as set up during the reline impression what should the operator do and why |
rock the framework around its fulcrum to ensure desired support is restored |
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when flasking the denture does the impression of the ridge as well as the RPD to be relined go into the same parts of the flask |
no they are in separate parts |
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what will occur if the denture flask for a reline is not completely closed before relining |
the entire RPD will be supported solely by the denture base |
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during the conventional construction, what would incomplete flask closure only result in |
premature contact on denture teeth |
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what is a danger of deflasking and RPD reline |
damage of RPD framework esp clasp arms |
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what is done to the denture base and the denture teeth before chairside reline material is placed |
cover these areas with tape to avoid getting reline material on the |
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how long will it take for most chairside resin relines to completely polymerize |
12-15 minutes |
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2 expectations for intraoral (chairside) reline material |
porous lack color stability |
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indicated when denture bases do not extend to cover all tissues, when denture has fractured, or base is discolored |
rebase |
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first step of RPD rebasing |
relieve and shorten resin, cover borders with compound and do border molding |
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what is done after border-molding is done for rebasing |
take impression as done with reline |
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how should the cast be poured for a rebase--with entire framework or only the edent ridge area |
only the edent ridge area |
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how far is the old denture resin removed |
stop short of denture teeth |
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what reduces having an observable demarcation line between the old resin and the rebase resin |
shape old resin borders to 90 degrees to external surface |
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what should the junction of the new and old resin be in a rebase when esthetics are not a concern to reduce stress concentration and increase strength |
rounded junction |
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what can be done if the framework still fits but the teeth and denture base are shot |
heat resin from tissue side and pry it from retentive framework |
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what is done with a framework that fits and has had its base and teeth removed |
placed back in pts mouth and take impression framework must come out with impression |
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how is the framework recovered from the cast once it is poured up |
pry it off along inferior border of the major connector |
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how is a denture base repaired if both pieces are present (only resin involved, no framework problems) |
put pieces back together with wax, pour stone on tissue side, open and dovetail base at the fracture line, overbuild resin, complete polymerization in a pressure pot, finish and polish |
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when replacing a denture tooth on an RPD how much denture base is removed |
enough to allow at least 2mm of repair resin beneath the denture tooth |
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why is resin slightly overbuilt during repairs |
to account for polymerization shrinkage |
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does the edent ridge offer support for the RPD?
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no, abutment teeth absorb the forces
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how many impressions for tooth supported RPD (Kennedy III)
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one as long as ST is in anatomic form
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what does a corrected cast do
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captures teeth in their anatomic position and the residual ridge tissue in functional form
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3 requirements for corrected cast
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1) record and related tissues under uniform loading
2) distribute load over as large an area as possible 3) accurately delineate peripheral extension of denture base |
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what type of bone displays an irregular surface that can irritate overlying ST when stressed
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cancellous
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5 factors influencing support of /de base
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1) quality of ST over ridge
2) type of bone in load bearing area 3) design of prosthesis 4) amount of tissue coverage of denture base 5) anatomy of denture bearing arch |
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will the ridge give the denture base more or less support if its overlying ST is thick/displaceable
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less
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what ST covering of the edentulous ridge offers the greatest support for the RPD
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firm, tightly attached, moderate thickness
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2 improvements removal of redundant tissue, esp over max tuberosities, offers the RPD
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1) minimize vert displacement
2) improve resistance to lateral displacement |
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cancellous or cortical bone: which is less able to resist vertical forces
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cancellous because irregular surfaces irritates overlying tissue
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where should you direct forces when considering bone
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dense cortical regions (buccal shelf)
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most efficient method of controlling rotational movement of a de
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use of one or more indirect retainers anterior to the fulcrum line
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if the RPD is a bilateral de (ken I) how many and where should ID retainers be
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one ID retainer on each side of the arch
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how many and where are the ID retainers placed in a unilateral de (kenn II)
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one, anterior to fulcrum line and on opposite sides of arch from the de
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if the de RPD denture base is overextended and impinges on movable tissues, ortho movement of teeth will occur where
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anterior to fulcrum lin
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max arch primary stress bearing area
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crest of ridge
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why can max arch vertical slop be used as a stress bearing area?
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not oriented perpendicular to vertical forces
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the max buccal slope resists what forces
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lateral
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what other part of the maxilla provides some resistance to displacement from vertical forces but is prone to ulceration since it is thin mucosa
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HP
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what must be done if the max crestal mucosa is not firm and dense
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surgical correction
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can the mandibular crestal ridge be used as a primary stress bearing area and why
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no it is cancellous bone
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mand primary stress bearing area for de..
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buccal shelf
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what provides vertical for resistance in the mandible
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buccal shelf, almost perpendicular to vertical forces
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what provides horizontal resistance in mand de
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buccal and lingual slopes of ridge
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why is it difficult to get the peripheral extension of the mand denture base recorded
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floor of mouth is distensible
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what other RPD type requires a dual impression technique
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long span anterior edentulous (6 teeth, Kenn IV)
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physiologic impression
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records the ridge portion of the cast in its functional form by placing an occlusal load on the impression tray during the impression procedure
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selected pressure impression
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intended to equalize the support between the abutments and ST
directs forces to the portions of the ridge that are most capable of withstanding force done by relieving the tray in some areas and allowing the tray to contact the ridge in other areas |
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in the selected pressure impression technique, areas where the tray is not relieved will have greater or less ST displacement
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greater displacement
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for the corrected cast impression, what is attached to the impression tray
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the RPD framework
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STs are _______ if insertion and wear of the prosthesis produces no adverse ST response
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minimally displaced
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what can occur as a result of excessive displacement of ST
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inflamm response and bone resorption
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McLean physiologic impression
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custom tray for edent area then put that custom tray into an impression tray with hydrocolloid and take full arch impression
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functional reline method
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adds new surface to the intaglio of the denture base
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when doing a reline, what is placed on the cast to allow for new material to be added
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thin layer of metal (ash's no 7 metal)
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in the mouth, what is used as the final impression material for the functional reline
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ZOE paste or light bodied polysulfide paste
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for the reline, when will occlusal discrepencies be correted
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after the processing of base
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when making an impression tray for the corrected cast procedure, what is used to make the new tray
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framework on the master cast and resin placed over the frame, then tried in the mouth
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when trying in the resin covered framework tray, the edge of the tray should be how far from the depth of the buccal vestibule in the pt's mouth
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2–3mm
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how far post should the mand tray reach
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2/3 height of retromolar pad
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overextended tray will cause what on abutment teeth
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constant force on abutment teeth as border tissues attempt to unseat denture
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2 border moldings that must be done on the de framework tray
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1) ant to pos of buccal flange
2) lingual and distolingual flanges |
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proper border molding results in what
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tongue and other tissues move without dislodging tray
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3 objectives of fluid wax impression
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obtian max extension of peripheral borders w/o interfering with moveable tissues
record stress bearing areas of ridge in functional form record non–pressure bearing areas in their non–functional form |
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waxes that are firm at room temp and have ability to flow at mouth temp
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fluid wax
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will a thin or thick layer of fluid wax flow less readily
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thin is less ready
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fluid wax will not support itself beyond __mm
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2mm
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after 5 min fluid wax looks ___ in areas of tissue contact
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glossy
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how long must fluid wax impression be left in mouth
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12 min
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impression technique that seeks to direct forces to those portions of the ridge able to absorb stress and to protect areas of ridge least able to absorb stress (intaglio surface of tray is selectively relieved)
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selected pressure
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which are is relieved on a mand de tray
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posterior crest of ridge
(relieved down to metal, allowing for minimal tissue displacement during impression) |
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impression material of choice if residual ridge is free of gross undercuts, or when flabby tissue is involved
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ZOE
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more or less viscous impression material results in greater tissue displacement
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less viscous
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good impression material for moderate to severe undercuts
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polysulfide rubber base
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what is done with the original master cast to make the final corrected cast
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old ridge is cut out
framework impression placed on remaining teeth and fixed wiht modeling plastic bead and box to give 2–3 mm land area |
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what should always accompany as master cast to the lab
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properly designed diagnostic cast
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what needs to be IDed on work auth
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1) MC to use
2) teeth to be clasped 3) type of clasp to use 4) amt of undercut each assembly egages |
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blockout for tooth–tissue supported RPD (kenn I and II)
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parallel or tapered
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how far to place a finish line from an abutment
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1.5mm to ensure resin will not contact marginal gingiva
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what determines the ultimate fit of the framework as far as processing is concerned
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refractory cast expansion
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refractory materials are also called
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investments
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gypsum bonded refractory materials are called what type of investments and are used to cast what materilas
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low heat investments
type IV partial denture gold and ticonium |
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cast made form what is the foundation for waxing and casting procedures
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refractory material
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why is the refractory cast trimmed within 6mm of proposed design
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gas escape during casting
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most critical part of design transfer to the refractory cast
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individual clasp position
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method of choice for RPD casting
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induction casting
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induction casting
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casting based on the electric currents in a metal core induced from a magnetic field
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electropolishing
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rough finishing where atoms of metal from rough projections on the framework go into solution before those on smooth areas do giving a satin–like finish
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what direction does wrough wire flex in
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all directions
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method of attaching w–w in a repair sitch
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embe din the resin
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when is w–w used
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interim RPD
transitional prosthesis repair of fractured or distorted clasps |
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most dependable method to attach w–w to RPD
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solder wire to the framework after framework is complete
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disadv of incorporating wire into wax up and casting metal to it
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adversely affects clasp longevity
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best way to attach w–w
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solder onto lattice work well away from area where it will flex
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twin–flex clasp method...
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provides flexible clasp that is less noticeable to pt by placing it in a measured undercut on a proximal surface of an abutment
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% of RPDs that do no fit on day of insertion
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75%
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tissue surface of framework should be finished to what texture
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fine matte
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2 requirements of internal and external finish lines on framework
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sharply defined and undercut to provide mechanical retention
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most impt quality of MC
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rigidity
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order of adjusting framework
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fit to teeth and tissues of supporting arch
occlusion adjusted |
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when checking de framework, should pressure be placed over de area?
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no, it would cause framework to rock and give inaccurate disclosing wax readings
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most common areas of interferences
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shoulders of circumferential clasp
interproximal extensions of lingual plate |
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when is a jaw relations record take
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after corrected cast procedure for Kenn I or II
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what is the desired occlusal scheme for c/c
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bilateral balanced
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what is the desired occlusal schedume for FPD
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disclude posterior teeth
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goal for RPD occlusal scheme
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establish and maintain harmonious relationship between oral structures and provide effective, esthetic mastication
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2 general arbitrary points for VDO measurement
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top of pt's nose to pt's chin
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2 important vertical dimentions
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physiologic rest
occlusal vertical dimension |
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what determines the mand position in phys rest position
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muscle balance
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diff bt phys rest dimension and occlusal VDO
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2–4mm
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when should changin gth eVDO be considered
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when pt has significant VDO decrease
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greater than __mm should consider increasing VDO
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4,,
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generally, MIP is usually __ and ___ to CR
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anterior and inferior
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whip–mix condylar guidance is adjusted using what jaw relation records
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lateral
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frankfurt horizontal
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2 condylar locations and the lowest part of the bony orbit (orbitale to tragion)
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MC jaw relations medium
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polyether or polyvinylsiloxane
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the occlusal rim or opposing occlusal rims should have how much space interocclusally
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1mm
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inclination of the condylar guidance is dependent on what
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anatomy of the glenoid fossae
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estimating length of one central incisor
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divide pts chin to hairline distance by 16
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only time porcelain teeth are indicated
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when they oppose other porcelain teeth
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to determine arch length on a distal extension, measure from where to where
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mand: distal of natural canine to incline of mand ramus
max: dital of natural canine to mesial of tuberosity |
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what is a mold consideration for posterior teeth
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choose slightly longer
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desired occlusal scheme when pt in MIP
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simultaneous bilateral posterior occlusal contact with all natural teeth occluding
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desired occlusal scheme for tooth bourne
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mutually protected, trying to avoid group funciton
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desired occlusal scheme for rpd/c
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balanced (bilateral simultaneous contact of ant and post in centric and eccentric)
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desired occlusal scheme for class IV rpd
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light contact with opposing natural
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4 times when jaw relations must be verified
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1) if accuracy of mounting is in question
2) rpd/c 3) all post teeth in both arches replaced 4) no opposing natural teeth, need verification of VDO |
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verifications made at same or increased VDO
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slightly increased
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mand can maintain non–translating arc for what range
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10–20mm
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if baseplate wax used for jaw relations, when does mounting need to be done by
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30 min
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ging height is highest over which tooth
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canine
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what does waxing in a slight concavity bt the gingival bule and the periphery of the denture base do
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aides retention by giving area for cheek to fold into
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borders of tooth supported segments of rpd should be waxed __mm apical to the adjacent ging margin
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5mm
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split mold investing
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completed mold contains master cast and metal framework in one portion of denture flask and artificial teeth are in remaining portion of the denture flask
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amount of clearance bt occlusal surface of teeth and top of flasks middle segment
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15mm
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3 objectives of insertion appt
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1) eval correct fit of denture base
2) correct occlusion 3) adjust retentive clasps |
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common area for denture bases to contact and require adjustment at delivery
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lateral walls of ridge and no contact on crest of ridge
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cheek biting caused by
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insufficient horizontal overlap of max and mand posterior teeth
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soft reline does what
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ease ST stress
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hard reline does what
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replace bone loss
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3 defect categories
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integrity
wear reline |
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6 things rpd alloy selection is based on
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weight
casting accuracy availability/cost versatility clinical experience mechanical properties |
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5 mech properties when choosing rpd alloy
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hardness
yield strength elastic modulus fracture and fatigue strength ductility (%elongation) |
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what is the problem with a light casting alloy
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less accurate bc less weight to push metal into form when centrifuged
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inc this mech property and the clasps will engage in less undercut, you get more retention the less elastic deformation there is
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elastic modulus
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what is increased by increasing yield strength
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clasp deflects elastically more before plastically deformed, can engage more undercut
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if inc fracture strength
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alloy less likely to fracture or fatiguei
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f inc ductility there is less chance of...
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fracture during adjustment or fatigue
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stiffer means less or more elastic modulus
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less
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greater yield strength with ww or cast
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ww
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what does heating do to yield strength
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lowers
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hanau articulators are adjusted using what type of jaw relation records
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protrusive
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whip mix condylar guidance is adjusted using what jar relation records
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lateral |
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inclination of the condylar guidance is dependent on what |
anatomy of glenoid fossa |
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side to side or back and forth motion of RPD limited |
stability |
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up and down or rocking motion limited in RPD |
retention |
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vertical forces evenly placed between tissue and teeth |
support |
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lack of movement that produces sore spots |
comfort |
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minimize visable clasps and facial support |
esthetics |
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moon considers permanence of the RPD as concerned with what |
bone loss |
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what is the major defect of RPD |
stability |
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which RPD type has more problems |
mandibular |
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soft reline seeks to do what |
ease soft tissue stress |
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hard reline seeks to do what |
replace bone loss |
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4 functions of RPD |
mastication esthetics phonetics self esteem |
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3 defect categories |
integrity wear reline |
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how can there be broken clasps, rests, or broken portions of framework |
fatigue, dropped, casting voids |
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6 things RPD alloy selection is based on |
weight casting accuracy availability/cost versatility clinical experience mechanical properties |
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what are the 5 mechanical properties considered when choosing an RPD alloy |
hardness yield strength elastic modulus fracture and fatigue strength ductility (% elongation) |
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what is a problem with a light casting alloy |
less accurate casting because less weight to push metal into form when centrifuged |
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increase in this mech property and teeth will wear quicker and will take more grinding to adjust |
hardness |
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increase this mechanical property and the clasps will engage less undercut. you get more retention the less elastic deformation there is |
elastic modulus |
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is it better to have a softer or stiffer major connector |
stiffer, distributes force across arch |
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what is increased by increasing yield strength |
clasp deflects elastically more before plastically deformed |
