Pros midterm study questions

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Note: Kennedy Classification

I – Bilateral edentulous areas located posterior to the natural teeth

II – A unilateral edentulous area located posterior to the remaining natural teeth

III – A unilateral edentulous area with natural teeth remaining both anterior and posterior to it.

III – A single, but bilateral (crossing the midline), edentulous area located anterior to the remaining natural teeth

Chapter 4:
1. What elements prevent movement of the base(s) of a tooth-supported denture toward the basal seats? This movement is primarily prevented by rests on abutment teeth and to some degree by any rigid portion of the framework located occlusal to the height of contour. (Intracoronal rest use is permissible in a tooth-supported denture to provide occlusal as well as horizontal stabilization.)
2. Movement of a distal extension base away from basal seats will occur as a rotation movement or as horizontal movement.
3. What is the difference between fulcrum line and axis of rotation?

A: Fulcrum line is a specific type of axis of rotation. Rotation about an axis through the most posterior abutments. Fulcrum line is the center of rotation as the distal extension base moves toward the supporting tissue when an occlusal load is applied. This axis may be through occlusal rests or any other rigid portion of a direct retainer assembly located occlusally or incisally to the height of contour of the primary abutments.

4. Identify the fulcrum line on a Class I arch; Class II, modification 1; and a Class IV.

A: Page 31, fig 4-7 shows Class II, modification 1

5. In the treatment planning and design phase of partial denture service, the functional movements of RPD's should be considered when designing the individual __________ ___________ of the prosthesis. ( 2 words)

A: component parts

6. Forces are transmitted to abutment teeth and residual ridges by RPD's. One of the factors of a force is its magnitude. List the other three factors of a force that a dentist must consider in designing RPDs.

A: Factors to consider with a force: direction, duration, frequency, magnitude

7. The design of a removable restoration necessitates consideration of mechanics and biological considerations. True or False?

A: True
8. Of the simple machines, which two are more likely to be encountered in the design of RPD's?

A: The lever and inclined plane.
9. What is a lever? A cantilever?

A: A lever is a rigid bar supported somewhere along its length. The support point of a lever is the fulcrum. A cantilever is a beam supported at one end and can act as a first-class lever.

10. Name the three classes of levers and give an example of each.

A: Classification of levers is based on location of the fulcrum (can be a tooth surface such as an occlusal rest), resistance (provided by a direct retainer or a guide plane surface), and direction of effort force (force of occlusion or gravity). For a visual depiction of first, second, and third class levers, see page 28, Fig.4-2.

First class: Teeter-totter

Second class: Wheelbarrow

Third class: Fishing pole
11. Of the three classes of lever systems, which two are most likely to be encountered in Removable Partial Prosthodontics? Guess is first and second class since all three are found in RPDs.
12. Explain how one would figure the mechanical advantage of a lever system given dimensions of effort and resistance arms.

A: (p. 30) Mechanical advantage = Effort arm ÷ Resistance arm

13. What class lever system is most likely to be encountered with a restoration on a Class II, modification 1 arch when a force is placed on the extension base?

A: p. 31) First class lever system. See Figure 4-7.

14. What factor permits a distal extension denture to rotate when the denture base is forced toward the basal seat?

A: (P.31) If tissue support under extension base allows excessive vertical movement toward the residual ridge. See figure 4-6.

15. Is an abutment tooth better able to resist a force directed apically or horizontally? Why?

A: Apically. Because more periodontal fibers are activated to resist vertically directed force than are activated to resist horizontally (off-vertical) directed force. Horizontal axis of rotation is located somewhere in root of tooth. See figure 4-9. Page 32.

16. Where is the location of the horizontal (tipping) axis of an abutment tooth?

A: Horizontal axis of rotation is located somewhere in root of tooth.

See Figure 4-9, page 32.

  1. Why should components of a direct retainer assembly be located as close as possible to the tipping axis of a tooth?

A: Forces placed closer to the support reduces the effort arm. Figure 4-10, page 32. Therefore, placing the components of a direct retainer assembly as close as possible to the tipping axis of the tooth reduces the effort arm causing the tipping action of the tooth.

Chapter 5
1. A Class I removable partial denture should have seven components. Name the seven components.

  • major connectors

  • minor connectors

  • rests

  • direct retainers

  • stabilizing or reciprocal elements (as parts of a clasp assembly)

  • indirect retainers (if the prosthesis has distal extension bases)

  • one or more bases, each supporting one/several replacement teeth

2. Define the term major connector in your own words.

  • the component of the partial denture that connects the parts of the prosthesis located on one side of the arch with those on the opposite side

  • the unit of the partial denture to which all other parts are directly or indirectly attached

  • the component provides cross-arch stability to help resist displacement by functional stresses

3. What are the nine desirable characteristics of major connectors?

  • made from an alloy compatible with oral tissue

  • is rigid and provides cross-arch stability thru the principle of broad distribution of stresses

  • does not interfere with and is not irritating to the tongue

  • does not substantially alter the natural contour of the lingual surface of the mandibular alveolar ridge or of the palatal vault

  • does not impinge on oral tissue when the restoration is placed, removed, or rotates in function

  • covers no more tissue than is absolutely necessary

  • does not contribute to the retention or trapping of food particles

  • has support from other elements of the framework to minimize rotation tendencies in function

  • contributes to the support of the prosthesis

4. What purposes are served by rigid major connectors as contrasted with flexible connectors?

  • it effectively distributes forces throughout the arch and acts to reduce the load to any one area while effectively controlling prosthesis movement

  • if it were flexible, the ineffectiveness of connected components jeopardizes the supporting oral structures and can be a detriment to the comfort of the patient, cause damage to abutment teeth, injury to residual ridges, or impingement of underlying tissue

5. Major connectors should be located in a favorable relation to moving tissue, gingival tissue, and areas of bony and tissue prominences. What difficulties would the patient encounter if the preceding guidelines are not carried out?

  • if placed too close to movable tissue, the denture can be displaced

  • if it impinges on gingival tissue, it can cut off the blood supply to the tissue

  • areas of bony and tissue prominences should be avoided during placement and removal so as not to damage the tissue or cause pain (I couldn’t find this one in the book)

6. Name and draw the cross-sectional form of the basic mandibular major connector

  • the basic form of a mandibular major connector is a half pear shape located above moving tissue but as far below the gingival tissue as possible

  • the superior border of a lingual bar connector should be tapered toward the gingival tissue superiorly with its greatest bulk at the inferior border, resulting in a contour that is a half pear shape

7. Margins of major connectors adjacent to gingival tissue should be located far enough from the tissue to avoid possible impingement when the denture rotates from functional and parafunctional forces. The superior border of a lingual bar should be located how far away from gingival crevices?

  • 4 mm

8. Describe two methods by which the location of the inferior border can be accurately determined.

  • measure the height of the floor of the mouth in relation to the lingual gingival margins of adjacent teeth with a periodontal probe. during these measurements, the tip of the patient’s tongue should be just lightly touching the vermilion border of the upper lip. these measurements can then be transferred to the casts

  • use an individualized impression tray having its lingual borders 3 mm short of the elevated floor of the mouth and then use an impression material that will permit the impression to be accurately molded as the patient licks the lips. the inferior border of the planned major connector can then be located at the height of the lingual sulcus of the cast of the impression

9. What is meant by the word relief? Rationalize planned relief for a lingual bar and give quantitative rules of thumb that depend on the contour of the anterior, lingual alveolar ridge.

  • relief is space between the lingual bar, lingual plate, or any place where the framework crosses gingival tissue; and the movable tissue so that the framework doesn’t impinge on the tissue

  • (I couldn’t find the second half of this question’s answer)

10. Discuss those clinical observations that indicate the choice of a lingual bar as a major connector.

  • if there is sufficient vertical distance between the gingival tissue of anterior teeth and the floor of the mouth to allow the superior border of the bar to be a minimum of 4 mm away from the gingiva and the inferior border to be above the height of the floor of the mouth then it is indicated

11. What is the form of a mandibular linguoplate major connector?

  • the upper border should follow the natural curvature of the supracingular surfaces of the teeth and should not be located above the middle third of the lingual surface except to cover the interproximal spaces to the contact points. the half pear shape of the lingual bar should still form the inferior border providing the greatest bulk and rigidity.

  • basically, if the rectangular space bounded by the lingual bar, the anterior tooth contacts and cingula, and the bordering minor connectors is filled in, a linguoplate results

12. Give four clinical observations that indicate use of a linguoplate rather than a lingual bar as a major connector.

  • when a lingual frenum is high or the space available for a lingual bar is limited

  • in class I situations in which the residual ridges have undergone excessive vertical resorption. Flat residual ridges offer little resistance to the horizontal rotational tendencies of a denture.

  • for stabilizing periodontally weakened teeth, splinting with a liguoplate can be of some value when used with definite rests on sound adjacent teeth

  • when the future replacement of one or more incisor teeth will be facilitated by the addition of retention loops to an existing linguoplate

13. Draw a sagittal section through a cast that shows the basic form of a linguoplate.

  • see page 38

14. What is the difference in determining the location of the inferior borders for lingual bars and linguoplates?

  • the inferior border of a lingual bar must be located so that it does not impinge on the tissue in the floor of the mouth because it changes elevations during the normal activities of chewing and speaking. the linguoplate inferior border should extend past gingival crevices and margins and end in an area that is above movement of the floor of the mouth and in an ideal location that is comfortable to the patient

15. Describe the superior extent of the apron portion of a linguoplate in relation to the lingual surfaces of teeth contacted by the major connector.

  • it should follow the natural curvature of the supracingular surfaces of the teeth and should not be located above the middle third of the lingual surface except to cover interproximal spaces to the contact points

16. What are the indications for use of a lingual bar-continuous bar-type of major connector? (see page 39 for a picture of this type of connector/ 5-5 D)

  • when a linguoplate is the major connector of choice, but the axial alignment of the anterior teeth is such that excessive blockout of interproximal undercuts must be made or when wide diastemata exist between the lower anterior for better esthetic results

17. Interpret in your own words the rationale of this statement made by McCracken: “No component of a partial denture should be added arbitrarily or conventionally. Each component should be added for a good reason and to serve a definite


  • I didn’t answer this one but the quote is on page 42.

18. How may a linguoplate be modified to avoid an over display of metal when used on an arch in which wide diastemata exist between anterior teeth?

  • the linguoplate can then be constructed so that the metal will not appreciably show through the spaced anterior teeth. see page 43 for an example of this connector. it is called an interrupted linguoplate

19. The dentist alone is responsible for the design of the restoration, which is based on both biological and mechanical principles. Give the dimensional specifications of th e wax patterns of mandibular major connectors.

  • I have no idea-I emailed Dr. Olin

20. At what point in treating the partially edentulous patient must the choice of maxillary and mandibular major connectors be made? Explain.

  • after considering the diagnostic data and relationg them to the basic principles of major connectors

  • the major connectors are what everything else in the partial denture is connected to and built upon so it should be the first component of the framework to be designed.

21. There are basically four types of maxillary major connectors. Name and describe them.

  • single palatal strap (includes combination anterior/posterior palatal strap type connectors) = these are single, broad palatal strap connectors that are a minimum of 8 mm wide

  • palatal plate = these are any thin, broad, contoured palatal coverage used as a maxillary major connector and covering one half or more of the hard palate

  • U-shaped palatal connector = these are usually very bulky to maintain rigidity and are the least desirable major maxillary connector

  • single palatal bar (includes combination anterior/posterior palatal bar type connectors) = less than 8 mm in width and relatively bulky again to maintain rigidity. these are also undesirable connectors but for some reason are used too often

22. What objections are associated with the use of the single palatal bar-type major connector?

  • for a single palatal bar to have the necessary rigidity for cross-arch distribution of stress, it must have concentrated bulk, which, unfortunately, is all too often ignored. It is not as comfortable to the patient. this includes the anterior/posterior palatal bar connector as well.

23. Which type of palatal major connector is probably the most rigid and at the same time covers the smallest amount of soft tissue?

  • single palatal strap

24. In what situations would one be most likely to use a single palatal strap-type major connector?

  • bilateral tooth-supported prostheses, even those with short edentulous spaces, are effectively connected with a single, broad palatal strap connector, particularly when the edentulous areas are located posteriorly.

  • for reasons of torque and leverage, a single palatal strap major connector should NOT be used to connect anterior replacements with distal extension bases

  • FYI = the combo anterior/posterior palatal strap connector may be used in almost any maxillary partial denture design (except in those pts. with large posterior palatal tori)

25. There are definite rules of thumb for the location of the anterior and posterior borders of all palatal major connectors. Describe the relationship of the borders to rugae, junction of hard and soft palates, gingival crevices, pterygomaxillary notches, and palatal tori.

  • anterior borders should follow valleys between rugae and stay parallel to the line made by the rugae and be 6 mm away from the anterior gingival margins

  • posterior borders are located just anterior to the soft palate and no farther posterior than the most posterior teeth

  • borders should not impinge upon tissue and if they do cover gingival tissue there should be some relief. also, if a border needs to cross gingival tissue, it should do so at right angles ALSO framework borders if possible should be 6 mm away from gingival margins

  • pterygomaxillary notches are used as most posterior extension of the denture base (acrylic portion?)

  • palatal tori should not be covered by major connector

26. Can adequate support be obtained by resting the palatal major connector on tooth inclines? Why?

  • major connector components resting on unprepared inclined tooth surfaces can lead to slippage of the denture or to orthodontic movement of the tooth and eventual impingement of gingival tissue

27. Rationalize this statement: “Either support the connector by definite rests on the teeth contacted, bridging the gingivae with adequate relief, or locate the connector far enough away from the gingivae to avoid any possible restriction of blood supply and entrapment of food debris.”

  • it already sounds pretty rationalized to me but it sounds like avoiding impingement of the gingival tissue is a very important issue when designing the major connector?

  • this statement can be found on page 46

28. Why should all gingival crossings by components of a framework be abrupt and at right angles to the major connector and bridge the gingivae with adequate relief?

  • a straight line is the shortest distance possible between the framework crossing the gingivae and the major connector and therefore less gingival tissue will be covered by the framework (the book didn’t have an answer to this question so this is the best I could come up with)

  • relief is once again important so that the tissue isn’t traumatized

29. Describe a continuous bar mandibular major connector and list the indications for its use.

  • when a linguoplate is the major connector of choice, but the axial alignment of the anterior teeth is such that excessive blockout of interproximal undercuts must be made

  • I think this basically means that if the teeth are all twisted funny and you can’t get the linguoplate to adapt well to the teeth because you have to block out so much that there’s too much relief between the teeth and framework that this is the type to use

  • there is a good example of this type of major connector discussed in this question and in question 16 on page 45

30. Describe a sublingual bar mandibular major connector and list the indications for its use.

  • the bar shape is essentially the same as that of a lingual bar, but placement is inferior and posterior to the usual placement of a lingual bar, lying over and parallel to the anterior floor of the mouth

  • it is indicated when the height of the floor of the mouth does not allow placement of the superior border of the bar at least 4 mm below the free gingival margin

  • it is generally accepted that a sublingual bar can be used in lieu of a lingual plate if the lingual frenum does not interfere or in the presence of an anterior lingual undercut that would require considerable blockout for a conventional lingual bar

  • look at page 39 figure 5-5 C for a picture

31. What clinical and diagnostic observations would lead to the selection of an anterior/posterior palatal strap-type major connector?

  • the only condition preventing their use is when there is an inoperable maxillary torus that extends posteriorly to the soft palate

  • it may be used with any Kennedy class of partially edentulous arch and is used most frequently in classes II and IV

32. Under what circumstances is full palatal coverage, by the major connector, indicated?

  • when the last remaining abutment tooth on either side of a class I arch is the canine or first premolar tooth and when the residual ridges have undergone excessive vertical resorption

33. Describe a palatal linguoplate major connector and explain why such a design would be selected.

  • it is used when residual ridges have undergone extreme vertical resorption and terminal abutments have suffered some bone loss and splinting cannot be accomplished

  • the design is similar to that of the mandibular linguoplate and the connector rests on rest seats prepared in the canines and covers the lingual portion of the anterior teeth in the same manner as the mandibular linguoplate

  • there is a good picture of this connector on page 50 figure 5-24

34. Describe the five steps outlined by Blatterfein for the design of palatal major connectors on a diagnostic cast of a Class I maxillary arch.

  • step 1 = outline primary bearing areas. primary bearing areas are those that will be covered by the denture base (see page 51 figure 5-25)

  • step 2 = outline nonbearing areas. nonbearing areas are the lingual gingival tissue within 5 to 6 mm of the remaining teeth, hard areas of the medial palatal raphe (including tori), and palatal tissue posterior to the vibrating line (the line between hard and soft palate) (see page 51 figure 5-25)

  • step 3 = outline connector areas. steps 1 and 2, when completed, provide an outline or designate areas that are available to place components of major connectors (page 51 figure 5-25)

  • step 4 = selection of connector type. selection of the type of connector is based on four factors: mouth comfort, rigidity, location of denture bases, and indirect retention. connectors should be of minimum bulk and should be positioned so that interference with the tongue during speech and mastication is not encountered. connectors must have a maximum of rigidity to distribute stress bilaterally. the double-strap type of major connector provides the maximum rigidity without bulk and total tissue coverage. in many instances the choice of a strap type of major connector is limited by the location of the edentulous ridge areas. when edentulous areas are located anteriorly, the use of only a posterior strap is not recommended. by the same token, when only posterior edentulous areas are present, the use of only an anterior strap is not recommended. the need for indirect retention influences the outline of the major connector. provisions must be made in the major connector so that indirect retainers may be attached.

  • step 5 = unification. after selection of the type of major connector based on the considerations in step 4, the denture base areas and connectors are joined (page 51 figure 5-25)

35. What is a minor connector?

  • those components that serve as the connecting link between the major connector or base of a removable partial denture and the other components of the prostheses; such as clasp assembly, indirect retainers, occlusal rests, or cingulum rests

36. What are the functions of minor connectors?

  • joins denture parts

  • transfers functional stress to the abutment teeth. this is a prosthesis-to-abutment function of the minor connector. occlusal forces applied to the artificial teeth are transmitted through the base to the underlying ridge tissue if that base is primarily tissue supported. occlusal forces applied to the artificial teeth are also transferred to abutment teeth through occlusal rests. the minor connectors arising from a rigid major connector make possible this transfer of functional stress throughout the arch

  • transfers the effect of the retainers, rests, and stabilizing components throughout the prosthesis. this is an abutment-to-prosthesis function of the minor connector. thus forces applied on one portion of the denture may be resisted by other components placed elsewhere in the arch for that purpose. a stabilizing component on one side of the arch may be placed to resist horizontal forces originating on the opposite side. this is possible only because of the transferring effect of the minor connector, which supports that stabilizing component, and the rigidity of the major connector.

37. Should minor connectors be structurally rigid or flexible? Why?

  • they should be rigid otherwise the transfer of functional stresses to the supporting teeth and tissue will not be efective

38. Describe the shape of a minor connector contacting axial surfaces of adjacent abutments at interproximal areas.

  • they should not be located on a convex surface.

  • they should be located in an embrasure where it will be least noticeable to the tongue

  • they should conform to the interdental embrasure, passing vertically from the major connector so that the gingival crossing is abrupt and covers as little of the gingival tissue as possible

  • they should be thickest toward the lingual surface, tapering toward the contact area

  • the deepest part of the interdental embrasure should have been blocked out to avoid interference during placement and removal, and to avoid any wedging effect on the contacted teeth

39. Identify six of the minor connectors in this drawing.

  • the drawing is on page 65.

40. What modification in the deisgn of a minor connector was suggested by Radfor? What are the suggested advantages and the disadvantages of this variation in design? What is the limitation of this design?

  • the application of this modification was suggested to be limited to the maxillary arch only (as the lingual cusp is the nonfunctional cusp and a minor connector traversing over a lingual cusp and into a rest seat for example would not interfere with occlusion), with the minor connector located in the center of the lingual surface of the maxillary abutment tooth

  • it is suggested that this modification reduces the amount of gingival tissue coverage, provides enhanced guidance for the partial denture during insertions and removal, and increases stabilization against horizontal and rotational forces.

  • however, because of its location, such a design variation could encroach on the tongue space and create a greater potential space for food entrapment.

  • this variation should be used with careful application

41. Minor connectors used to attach acrylic resin denture bases to major connectors should be located on both buccal and lingual sides of the residual ridge. Why?

  • such an arrangement will not only add strength to the denture base but also may minimize distortion of the cured base from its inherent strains caused by processing

  • it may not be a bad idea for everyone to glance at the purple section on page 56 for a longer, better explanation of this

  • also figure 5-36 on page 56 is a good figure to read about

42. State rules of thumb for the form and length of minor connectors connecting acrylic resin denture bases to major connectors.

  • YOU are GOING to HATE me! Sorry but the purple section above answers this question really well. I will do my best to summarize

  • when an artificial tooth will be placed against a proximal minor connector, the minor connector’s greatest bulk should be toward the lingual aspect of the abutment tooth

  • remember, those portions of a denture framework by which acrylic resin denture bases are attached are minor connectors and they should be completely embedded in the denture base

  • the junctions of these mandibular minor connectors with the major connectors should be strong butt-type joints but without lots of bulk

  • angles formed at the junctions of the connectors should not be greater than 90 degrees, thus ensuring the most advantageous and strongest connection between acrylic denture base and major connector

43. What advantages accrue to the restoration by having minor connectors for acrylic resin denture bases attached to the major connector in a butt-type joint?

44. Describe the best location for palatal finishing lines at the junction of major and minor connectors. How do you determine this optimum location on a cast? Why is it important that the natural contour of the palatal vault be restored with a removable restoration?

  • they are basically asking about the location of where the gridwork (which is a minor connector) and the major connector (say a palatal plate) should meet. just for clarification, the minor connector will meet the major connector and be thinner than the major one so that when the acrylic resin covers the minor connector it will meet up with the major connector at the same plane and the patient won’t feel the transition once placed in the mouth

  • if the finish line (where the two meet) is located too far mesially on the ridge, the natural contour of the palate will be altered by the thickness of the junction and the acrylic resin supporting the artificial teeth

  • if the finish line is located too far bucally, it will be most difficult to create a natural contour of the acrylic resin on the lingual surface of the artificial teeth

  • the location of the finishing line at the junction of the major and minor connector should be based on restoring the natural palatal shape, taking into consideration the location of the replacement teeth

  • figure 5-41 on page 60 is a good picture to clarify this concept

  • maintaining palatal vault contour is critical so that the patient experiences a natural feeling and enhancing speech


45. In addition to a more natural feeling contour, what other factors may be achieved by the use of anatomic replica patterns for palatal major connectors?

  • enhanced speech was all I could find, but I would assume that mastication and swallowing would be more comfortable if the palate were more anatomically correct

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