4031009
Description
Flashcards by Michael Brown, updated more than 1 year ago
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Created by Michael Brown
about 9 years ago
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| Question | Answer |
| What are the advantages of RPDs? | Simple Restore Function Restore Aesthetics Cost effective |
| What are the disadvantages of RPDs? | Plaque Retentive Aesthetics Denture Stomatitis (possible) Gum Stripping |
| What are the clinical stages of an RPD? | 1. Exam and Primary Impressions 2. Master Impressions 3. Jaw Registration 4. Tooth Trial 5. Co/Cr Trial 6. Co/Cr Wax Trial 7. Delivery 8. Review |
| Why are teeth lost? | Caries Periodontal disease Trauma Periapical disease Orthodontics Impaction |
| What are the consequences of losing teeth? | Bone resorption Loss of ST support TMJ problems Drifting/Tilting Aestehtics Function -> speech,mastication Pyschological impact |
| Draw and label Posselt's Envelope | |
| What is Craddock's Classification? | Classifies Support I. Tooth borne II. Mucosa borne III. Tooth and mucosa borne IV. Implant V. Implant and mucosa |
| What is Kennedy's classification? | Classifies saddle areas I. Bilat.Free End Saddle II. Unilat.Free End Saddle III. Unilat.Bounded Saddle IV. Ant.Bounded Saddle Mods -> Always defined by POST saddle ∴ Class IV cannot have mods. |
| Name the components of an RPD | Saddles Rests - occ, cing, incisal Clasps - occ/ging. approach Bracing and reciprocation Connectors - minor/major |
| What are the Adv/Disadv of mucosa borne dentures? | Adv - cheap, easy to make and adjust Disadv - poor support/retention, can damage tissues |
| What are the Adv/Disadv of tooth borne dentures | Adv - Good support, stability and retention Disadv - cost, complexity, difficult to add to, may require tooth preparation |
| What is the design process for an RPD? | 1. Outline saddles 2. Decide support 3. Retention - direct and indirect 4. Bracing/reciprocation 5. Connectors |
| Define support | - Resistance to occlusally directed forces -Transmission of load via the periodontal membrane or mucosa - Craddock's Classification |
| What are the functions of rest seats? Name some types Define position and size principles | Function - main -> Support other -> direct/indirect retention, prevent overeruption, recipcrocation Types -> occlusal, cingulum, incisal, onlay Position -> adjacent to saddle area OR mesial to free end saddle >3mm from ging.margins if acrylic Size -> large as possible >0.5mm and 1mm @ connectors |
| Define Retention | - Resistance to vertical dislodging - 3 types -> Mechanical (best) Muscular Physical via adhesion/cohesion |
| What is mechanical retention? | Clasps -> engage undercuts Close to saddle area as possible Always have rest on same tooth Occ.Approach e.g. Ring/Circumferential Ging.Approach e.g. I-Bar |
| What is the minimum length for a co/cr clasp? | 15mm |
| What size undercut is required for: co/cr? Gold? Stainless Steel? | Co/cr - 0.25mm Gold - 0.5mm Stainless Steel - 0.75mm |
| Other than clasps, how else can retention be achieved? | Guide Planes Change POI to different from POD |
| What is pattern of retention? What is acceptable? | Areas of denture with retentive features May be square, triangle or straight lined (diagonal) |
| Define Indirect Retention | 1. Resistance to rotational displacement forces 2. e.g. a rest preventing distovertical rotational displacement 3. If this rest moves closer to the axis of rotation then the fulcrum moves forward 4. Resists BL and distohorizontal forces e.g. major connector 5. Primarily used in free end saddles |
| What is an RPI? | - Stress relieving clasp system - Allows vertical rotation of D saddle w.out unwanted movement of the last standing abutment tooth - P & I disengage during function to allow this Made up of: R - Rest (Mesially on tooth) P - Proximal Plate - adjacent to saddle w/guide surface I - I-bar |
| What is the function of a connector? What are the 2 main types? | Stability Major Minor |
| Name some max.major connectors | Plate/Strap -> mucosa borne (~0.5mm thick) Bar -> tooth borne (~2mm thick) Ring/Horseshoe All described by ANT/MID/POST |
| Name some mand.major connectors | Lingual Bar - >8mm depth, 4x2mm Sublingual Bar - more depth needed Lingual Plate - rests on teeth & indirect retention Dental Bar/Labial Bar - rarely used |
| Describe minor connector uses | Transfer stress to/from abutment teeth Finish above the survey line Cover as little gingiva as possible Should cross ging.margin @ right angle for cleaning ease |
| How is a cast surveyed? | 1 - secure cast to table and tripod horizontally at common POD 2 - Use analysing rod to find undercuts 3 - Use graphite marker on abutments and related ST to mark undercuts 4 - Change POI as needed |
| Name 4 types of articulator | Simple Hinge Average Value Semi-Adjustable Fully Adjustable |
| What are the average angulations on an articulator for mounting casts? | 0° - incisal post 10° - incisal table 20° - pillars 40° - condyle |
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