Fpd,rpd and implant


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Fpd,rpd and implant

  1. 1. FPD,RPD and implant.
  2. 2. Page 330 3-A ceramometal posterior fixed partial denture pontic should. A. be constructed to have an occlusal surface one quarter the width of the tooth it replaces. B. be constructed to have an occlusal surface wider than the width of the tooth it replaces. C. cover as much mucosa as possible. D. provide adequate embrasure spaces
  3. 3. • The mesial, distal, and lingual gingival embrasures of the pontic should be wide open to allow the patient easy access for cleaning,3^.12.'620 and the contact between • pontic and tissue must allow the passage of floss from one retainer to the other. • Schillenberg page 478
  4. 4. • An occlusal rest preparation should be A. angular and box shaped with parallel vertical walls. B. rounded and spoon shaped. C. flat and with an obtuse angle to the proximal surface of the tooth.
  5. 5. • The outline form of an occlusal rest seat should be a rounded triangular shape with the apex toward the center of the occlusal surface. It should be as long as it is wide, and the base of the triangular shape (at the marginal ridge) should be at least 2. 5 mm for both molars and premolars. • mcckrRPD chapter 6 ,PAGE 70
  6. 6. 6-The base of a distal extension partial denture should cover the maximum support area because A. the force per unit area will be kept to a minimum. B. maximum number of artificial teeth can be placed. C. phonetics is improved. D. strength of the base is increased.
  7. 7. • Distal Extension Partial Denture Base • In a distal extension partial denture, the denture bases other than those in toothsupported modifications must contribute to the support of the denture. Such support is critical to the goal of minimizing functional movement and improving prosthesis stability.
  8. 8. • Although the abutment teeth provide support for the distal extension base, as the distance from the abutment increases, the support from the underlying ridge tissue becomes increasingly important. • Maximum support from the residual ridge may • be obtained by using broad, accurate denture bases, which spread the occlusal load equitably over the entire area available for such support
  9. 9. • The snowshoe principle, which suggests that broad coverage furnishes the best support with the least load per unit area, is the principle of choice for providing maximum support. Therefore support should be the primary consideration in selecting, designing, and fabricating a distal extension partial denture base. Of secondary importance (but to be considered nevertheless) are esthetics, stimulation of the underlying tissue, and oral cleanliness • mcckrRPD Chapter9 page 130
  10. 10. 8-The primary stress bearing area of the maxillary complete denture is the A. hard palate. B. alveolar ridge. C. median palatal raphe. D. zygoma.
  11. 11. • the horizontal portion of the hard palate lateral to the midline provides the primary support area for the denture. In the area of the rugae, the palate is set at an angle to the residual ridge and is rather thinly covered by soft tissue. This area contributes to the stress-bearing role, though in a secondary capacity. The submucosa covering the • incisive papilla and the nasopalatine canal contains the nasopalatine vessels and nerves. • Prothodontic treatment for edendulous patient chapter13 page212.
  12. 12. • Both the maxillae and the palatine bone provide support for an upper denture.Individual differences in form determine how forces should be directed to these bones during function. A, Spiny projections that would irritate tissues under a denture. B, Rough and irregular bone of the maxillary ridges. C, Incisive foramen, which comes to lie closer to the crest of the ridge as resorption takes place. Thus the location of the incisive papilla, which covers the incisive foramen, in relation to the crest of the ridge is a guide to the amount of resorption that has occurred. D, Greater palatine foramen, which often has a spiny
  13. 13. 9-In the processing of methyl methacrylate, denture porosity is most likely to appear in the A. thickest portion. B. thinnest portion. C. buccal surface. D. palatal area.
  14. 14. Heat-Activated PMMA These resins are commonly processed in a brass flask using a compression molding technique (dough technique). The polymer and monomer are mixed in the proper ratio of 3:1 by volume or 2.5:1 by weight. The mixed material goes through four stages: first, a wet, sandlike stage; second, a tacky fibrous stage as the polymer dissolves in the monomer; third, a smooth, doughlike stage, suitable for packing into a mold; and fourth, a stiff, rubberlike stage.
  15. 15. Dough formation is assisted by internal plasticizers chemically attached to the polymer beads that locally softens them and facilitates monomer diffusion. After wax elimination, the dough is packed in a gypsum mold. The flasks are placed, under pressure, in a time-temperature controlled water bath to initiate polymerization of the resin.
  16. 16. The polymerization reaction is exothermic in nature and should be carefully controlled to avoid a marked increase in temperature, which may exceed the boiling point of un reacted monomer (100.8˚C), leading to denture porosity. Gaseous porosity due to rapid heating and monomer evaporation appears as fine, uniform spherical pores, localized more often in the thicker portions of the denture
  17. 17. Inadequate pressure during flask closure, an insufficient amount of dough present on packing of the mold, or improper mixing of powder/liquid components may also result in denture porosity. The resulting porosity will inevitably compromise the physical properties and denture esthetics and may promote the accumulation of denture deposits, which could adversely affect the health of the denture-supporting tissues. Prothodontic treatment of edentulous patient Chapter 12 page 190
  18. 18. Page 331 1-In processing (polymerizing) an acrylic denture in a water bath, a correct temperature control is desired because of the possibility of A. shrinkage of the denture. B. volumetric expansion of the denture causing an open bite. C. warpage. D. porosity due to boiling of the monomer. E. crazing of the denture base around the necks of the teeth.
  19. 19. • Like previous answer In general, heat-activated acrylic resins are polymerized by placing the flasks in a constant temperature water bath at 74˚C (165˚F) for 8 hours or longer with or without a 2- to 3-hour terminal boil at 100˚C. A shorter cycle involves processing the resin at 74˚C for approximately 2 hours then boiling at 100˚C for 1 hour or longer. Prothodontic treatment of edentulous patient Chapter 12 page 190
  20. 20. After the polymerization procedure, the denture flasks are cooled slowly to room temperature toallow adequate release of internal stresses and thus minimize warpage of the bases. Deflasking thenfollows and should be done carefully to avoid fracture or flexing of the dentures. The popularity and relative simplicity of the compression molding technique are usually overshadowed by the high-processing stresses that are induced in the resins during polymerization.
  21. 21. These stresses result from various factors. First, polymerization shrinkage, which occurs as polymer chains are formed, accounts for a volumetric shrinkage of about 7%. Second, thermal shrinkage follows as the resin cools. In addition, differences in thermal contraction of the resin and gypsum mold collectively yield stresses in the resin. It is tempting to assume that the release of such cumulative stresses may give rise to dimensional changes and inaccuracies in the fit of the denture base.
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