PROS MIDTERM STUDY QUESTIONS Chapter 2 – Clasp-Retained Partial Denture 1. In chronological order of accomplishment, give the six sequential, correlated phases in treating a partially edentulous patient with removable prostheses. - First phase: Patient education, patient should be educated thouroughly and understand the tx before any treatment is decided on or started. - Second phase: diagnosis (Health hx, dental health, etc.), treatment planning (surveying) , design of the partial denture framework, treatment sequencing and execution of mouth preparations (get good support, retention) - Third phase: Provision of adequate support for the distal extension denture base (not needed for tooth supported partials, need to make the distal base based on the functional impression / form (soft tissue shape under function) rather than the anatomic ridge form) - Fourth phase: establishment and verification of harmonious occlusal relationships and tooth relationships with occlusal and remaining natural teeth. - Fifth phase: initial placement procedures, adjustments to contours and bearing surfaces and to occlusal surfaces. Also, review patient instructions. - Sixth phase: follou up services, recall appointments 2. If the dentist and the patient share responsibility for the success of treatment, what must be undertaken to prepare patients to accept their responsibility? - Inform patient of the benefits of a removable partial denture - Advise Patients on proper oral care and maintenance procedures - Educate on use of the prosthesis to avoid misuse 3. Because treatment planning is the sole responsibility of the dentist, which if any of the following may be omitted as noncontributory to total treatment: (1) a complete health history, (2) a history of past dental experiences (3) an oral examination, (4) a radiographic examination, (5) an evaluation of occlusal relations of remaining teeth (6) a survey of diagnostic casts, (7) cost or (8) patient desires? - Neither 7 or 8 are mentioned as parts of the treatment plan. (see page 14) 4. A specific design of the removable restoration must be planned before mouth preparation procedures. The dentist (can-should not) delegate the responsibility for the design to a dental laboratory technician. - The dentist should not delegate the responsibility for the design to a dental laboratory technician. 5. Stability in a removable restoration (is – is not) desirable to help maintain the health of oral structures. A tooth – supported restoration usually (can – cannot) be made more stable than a restoration supported by teeth and residual ridges. - Stability in a removable restoration is desirable to help maintain the health of oral structures.
- A tooth – supported restoration usually can be made more stable than a restoration supported by teeth and residual ridges. 6. In the fifth phase of treatment (initial placement of the restorations), three things are done before the patient is given possession of the denture(s). Two of these are (1) correction of denture base contours and occlusal discrepancies that may have resulted form processing and (2) review of patient education, including adjustment expectations. What other step must be accomplished during the appointment? - Ensure that the patient understands the uses of the RPD and how to care for the denture and soft tissues. 7. What is the purpose of periodic recall of patients treated with removable partial dentures? - For evaluation of the response of the oral tissues, soft tissue changes - maintain oral health - evaluation of the acceptance of the prosthesis by the patient - Evaluate patient oral hygiene 8. What is the one predominant reason why the clasp-type or partial denture is used more often in most practices than is the internal attachment type of prosthesis? - Cost 9. Deficiencies in design and fabrication and those related to patient education are the culprits of limited success in treatment with removable prostheses. Avoiding these deficiencies will make the goal of prosthetic dentistry obtainable. This goal is to ______________, ___________, and ______________. - promotion of oral health - restoration of partially edentulous mouths - elimination of the ultimate need for complete denturesChapter 3 1. Would you agree that the primary purpose of a classification is to enhance communication among dentists? Support your answer? A: Yes and no. There are several classifications that have been proposed and the use of it would facilitate communication. In this book the Kennedy classification is the only one used as a way to better communication. So the use of classifications for partially edentulous areas does help communication, but one classification should be used. 2. Many classification systems have been propsed; however, the most widely accepted system in the US is the one proposed by _______________ in 1925. A: Dr. Edward Kennedy 3. A classification of partially edentulous arches should satisfy at least three requirements. List them. A:
- It should permit immediate visualization of the type of partially edentulous arch that is being considered - It should permit immediate differentiation between the tooth supported and the tooth and tissue supported removable partial denture - It should be universally acceptable 4. Kennedy divided al partially edentulous arches into _______ main types. A: 4 5. What is meant by modification space? A: Edentulous areas in an arch that are variations to the basic 4 classifications. Edentulous areas other than those determining the classification. 6. Which two classes of partially edentulous arches have the greatest incidence of occurrence according to Skinner? A: Skinner classification type III 7. Dr. O.C. Applegate contributed greatly to the application of the original Kennedy classification system. What was this contribution? A: He contributed eight rules governing the application of the Kennedy method 8. Classify the partially edentulous arches illustrated in Figure 3-3 (p. 23) A. Kennedy Class IV B. Kennedy class I C. Kennedy class II D. Kennedy Class III E. Kennedy Class III F. Kennedy Class III G. Kennedy Class IV H. Kennedy Class II I. Kennedy Class IIINote: 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 teethChapter 4:1. What elements prevent movement of the base(s) of a tooth-supported denture towardthe basal seats? This movement is primarily prevented by rests on abutment teeth and tosome degree by any rigid portion of the framework located occlusal to the height ofcontour. (Intracoronal rest use is permissible in a tooth-supported denture to provideocclusal as well as horizontal stabilization.)
2. Movement of a distal extension base away from basal seats will occur as a rotationmovement 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 themost posterior abutments. Fulcrum line is the center of rotation as the distal extensionbase moves toward the supporting tissue when an occlusal load is applied. This axis maybe through occlusal rests or any other rigid portion of a direct retainer assembly locatedocclusally 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 15. In the treatment planning and design phase of partial denture service, the functionalmovements of RPDs should be considered when designing the individual _____________________ of the prosthesis. ( 2 words)A: component parts6. Forces are transmitted to abutment teeth and residual ridges by RPDs. One of thefactors of a force is its magnitude. List the other three factors of a force that a dentistmust consider in designing RPDs.A: Factors to consider with a force: direction, duration, frequency, magnitude7. The design of a removable restoration necessitates consideration of mechanics andbiological considerations. True or False?A: True8. Of the simple machines, which two are more likely to be encountered in the design ofRPDs?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 alever 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 suchas 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 offirst, second, and third class levers, see page 28, Fig.4-2.First class: Teeter-totterSecond class: WheelbarrowThird class: Fishing pole11. 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 32.17. 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 stresses3. 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 prosthesis4. 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 tissue5. 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 shape7. 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 mm8. 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 impression9. 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 indicated11. 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 results12. 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 linguoplate13. Draw a sagittal section through a cast that shows the basic form of a linguoplate. • see page 3814. 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 patient15. 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 points16. 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 purpose.” • 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 linguoplate19. 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 the wax patterns of mandibular major connectors. • I have no idea-I emailed Dr. Olin20. 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 often22. 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 strap24. 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 connector26. 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 tissue27. 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 4628. 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 traumatized29. 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 4530. 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 picture31. 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 IV32. 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 resorption33. 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 5-2434. 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 rests36. 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 efective38. 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 teeth39. 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 application41. 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 about42. 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 connector43. 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? • these are strong joints and when placed at 90 degree angles it allows for
maximum strength44. 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 • AFTER ALL THAT-FIGURE 5-42 ON PAGE 60 EXPLAINS IT ALL! UGH!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 correct46. What are three ways to increase the bond strength between the minor connectors and the acrylic resin denture bases? How much is the bond strength increased? • answer is not in the chapter. I will email Dr. Olin to get the correct answer. Chapter 5 Questions1) What are the 7 components of a class 1 RPD?- The major connectors, minor connectors, rests, direct retainers, stabilizing components,indirect retainer and one or more bases supporting teeth.2) What is a major connector?
- supporting connection that unites both sides of the arch.3) What are 5 characteristics of major connectors?- Made w/rigid alloy compatible with oral tissue, rigid cross arch stability, doesn’t irritatetongue, doesn’t alter lingual contour, covers only necessary tissue.4) What is the purpose of a rigid major connector instead of a flexible connector?- To prevent distortion of the cross arch dimensions5) If major connectors are not place off tissue/bone, what could happen?- irritation of tissue, periodontal problems.6) Name and draw the form of a basic mandibular connector?- SEE BOOK P367) The superior border the mandibular major connector should be located at least _ mmfrom teeth?- 4mm8) How do you measure the inferior border space of a mandibular major connector?- Use a perio probe to measure, take and impression and measure.9) What is meant by relief?- Spaced made by placing wax spacer under the connector during RPD construction tokeep denture components off tissue.10) Discuss clinical choice of a lingual bar as a major connector.- SEE BOOK P.3911) What is the form of a mandibular plate?- SEE BOOK P.4012) Give 4 clinical observations that indicate use of a plate instead of a bar?- high lingual frenum, class 1 with major ridge resorption, stabilizing perio teeth, possiblefuture replacement of teeth (can be added easier).13) Draw lingual plate?- SEE BOOK P.4014) What is the difference in determining inferior borders of a lingual plate vs. bar?- undercuts must be blocked out15) Describe the superior aspect of the apron of a lingual plate.- closely adapted to the teeth, extending into non undercut embrasures.16) What are the indications for use of a lingual bar continuous bar type connector?
- when excessive block out of mandibular teeth are needed to place plate, a cingulum barmay be used.17) Not necessary (SEE BOOK)18) How may a lingual plate be modified to prevent display of metal in an embrasure?- The major connector can be constructed so that the metal is cut out of embrasure areas(SEE BOOK P.43)19) Give the dimensional specifications of the wax patterns of mandibular majorconnectors.- SEE BOOK P6420) At what point in treating the partially edentulous patient must the choice of maxillaryand mandibular connectors be made?- During design21) 4 types of maxillary connectors- palatal strap- single broad palatal connector- anterior posterior strap- complete palatal coverage- u shaped palatal connector22) What are the objections to using the single palatal bar-type major connector?- should not be used to connect anterior replacements with distal extension bases.23) What maxillary connector is the most rigid and covers the least soft tissue.- AP strap24) In what situation would you use a palatal strap type connector?- Bilateral edentulous spaces of short span in a tooth-supported restoration.25) Describe the relationship of rugae, junction of hard palate/soft palate, gingivalcrevices and palatal tori.- See Book.26) Can adequate support be obtained by resting the palatal major connectors on toothincline?- can lead to slippage of denture causing an orthodontic movement27) Does not pertain (SEE BOOK)28) Why should all gingival crossings be abrupt right angles and bridge with adequaterelief?- To prevent restriction of blood supply and entrapment of food debris.
29) Describe the continuous bar mandibular major connector and list indications.- When a lingual plate of sublingual bar is otherwise indicated but the axial alignment ofthe anterior teeth is such that excessive blockout of interproximal undercuts would berequired.30) Describe sublingual bar and its uses.- Where height of mandibular space is less than 6mm.31) Indication of AP type strap.- Excellent abutment and residual ridge, long edentulous spaces, palatal tori.32) When is full palatal coverage indicated?- if some or all anterior teeth remain, class II arch with large posterior space, class I withone to four missing premolars, absence of tor.33) Palatal Plate linguoplate connector (SEE BOOK P63)34) 5 steps of making major connectors on a diagnostic cast.-outline bearing areas-outline nonbearing areas- outline connector areas-select connector type- unification35) What is a minor connector?- connect major connector to other components of a denture.36) What are the functions of a minor connector?-transfer stress to abutment teeth.- transfer the effect of the retainers, rests and stabilizing components.37) Why should minor connectors be rigid?- must transfer stress and resist deformation.38) Describe the shape of minor connectors.-See Book P.5839) Identify minor connectors- See Book P.6140/41/42/43/44 SEE BOOK45) What factor may be achieved by the use of anatomic replica patterns for palatal majorconnectors?-?
46) What are ways to increase bond strength between minor connectors and acrylic resinbases?- 3 nail head connectors- angles formed 90 degrees with frameworkChapter 61. Define the word rest as a component of an rpd any component of a partial denture on a tooth surface that provides vertical support2. What are the functions of a rest the primary purpose is to provide vertical support, but in doing so, it also: maintains components in their planned positions maintains established occlusal relationships by preventing settling of the denture prevents impingement on soft tissue directs and distributes occlusal loads to abutment teeth overall, it serves to support the position of the partial and to resist movement toward the tissue3. Rests are defined by the surface of the tooth that is prepared to receive the rest. Therefore rests are occlusal rests, incisal rests, and lingual rests.4. Describe the form of an adequately prepared occlusal rest seat The outline form 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, the base (at the marginal ridge) should be at least 2.5mm. The marginal ridge must be lowered at least 1.5mm. The floor of the rest seat should be apical to the marginal ridge and should be spoon shaped. Angle formed between the occlusal rest and the vertical minor connector should be less than 90 degrees.5. Where is the deepest portion of an occlusal rest seat located "should be inside lowered marginal ridge at x." The x in the picture on page 69 is just at themiddle of the spoon shaped part. Exactly where you think it is!6. Draw a diagram of the approximate dimensions of an occlusal rest seat on a molar. a premolar 2.5 mm wide at base of triangle (bucco-lingually), 2.5 mm long (mesio-distally), marginal ridge lowered 1.5 mm, deepest portion at center of spoon. These dimensions are the same for molars and premolars.7. Why should the angle formed by the rest and the vertical minor connector from which it originates be less than 90 to direct the occlusal forces along the long axis of the tooth, also prevents slippage of the prosthesis away from the abutment8. Under what circumstances would one choose to prep a secondary occlusal rest on the same tooth when an existing occlusal rest seat is inclined apically toward the reduced marginal ridge and it cant be modified (center of spoon lowered) for fear of pulp perforation9. Describe the form of adjacent, interproximal occlusal rest seats the rests are prepared as individual occlusal rest seats , with the exception that the preps must be extended farther lingually than is ordinarily done. This answer doesnt quite seem right. I would take a look at the picture on page 71 because it seems like it is also extended further bucally.
10. What advantages are gained by using adjacent, interproximal occlusal rest seats rather than a single interproximal rest seat they are used to prevent interproximal wedging by the framework and they are designed to shunt food away from the contact points.11. Describe an internal occlusal rest seat and relate the circumstances under which it may be use a partial denture that is totally tooth supported by means of cast retainers on all abutment teethmay use intracoronal rests for both occlusal support and horizontal stabilization. The form of the rest should be parallel to the path of placement, slightly tapered occlusally and slightly dovetailed to prevent dislodgement proximally. If you want to read up a little more on these internal occlusal rests since we didnt talk about them much, check out page 71-or dont waste your time :0)12. How does one fabricate an internal occlusal rest seat internal rests are carved in wax or spark eroded in abutment castings. Ready made plastic rest patterns are available and can be waxed into a crown or partial veneer patterns, invested, and cast after having been positioned parallel to the path of placement with a dental cast surveyor.13. Rests may be placed on sound enamel, cast restorations, or silver amalgam restorations. Which of the three is least desirable for support of the rests. Why? Im still waiting for a definite answer from Dr. Olin. The book didnt come right out and answer this question and this would be an excellent test question!14. When preparing occlusal rest seats immediately adjacent to a proximal surface that has to be recontoured for optimum location of other components, which is accomplished first-rest seat preparation or recontouring of the axial surface of the abutment? Defend you answer. the preparation of occlusal rest seats always follows proximal preparation. If done the other way- the marginal ridge almost always ends up too thin with the center of the rest seat too close to it. Usually impossible to correct without making the prep too deep.15. What is the sequence of operations in preparing an occlusal rest seat in enamel? Name the cutting and polishing instruments used. use large round bur to lower the marginal ridge and to establish the outline form of the rest seat then a slightly smaller round bur is used to deepen the rest seat. The prep is smoothed by a polishing point. Fluoride gel should be applied to abutment teeth following enamel recontouring.16. How do you handle a small enamel defect encountered in preparing a rest seat. ignore it until the rest prep has been completed, then with small burs prepare the remaining defect to receive a small restoration.17. Suppose you expose dentin in preparing an occlusal rest seat in enamel-what then? Again, awaiting an answer from Dr. Olin18. Describe the form of a lingual rest seat preparation slightly rounded V shape (pointed incisally) at the junction of the gingival and middle third19. Which unrestored teeth may sometimes have such a lingual contour that an acceptable lingual rest seat may be prepared in enamel mandibular canines20. Five morphologic or anatomic factors must be evaluated in determining whether an abutmentcan support a lingual rest. Enumerate these five factors. Sorry!!!! Waiting for Dr. Olin
21. Most often, unrestored canines/ incisors should not be used for supports for lingual rests. Why? the lingual slope of the mandibular canine is usually too steep for an adequate lingual rest seat to be placed in the enamel. mandibular anteriors have too thin of enamel22. For what reasons should a rounded, inverted V notch form be used for a lingual rest seat? maintains the natural contour of the maxillary canine cingulum, the v-form is self-centering, and directs forces rather favorably in an apical direction.23. State the minimums for a lingual rest seat mesiodistally, labiolingually, and incisal-apically MD=2.5 to 3 mm LL=2 mm IA=1.5 mm24.Give the sequence of use of rotary instruments in preparing a lingual rest seat in enamel 1. inverted cone diamond 2. progress to smaller tapered stones with round ends 3. shaped abrasive rubber polishing points 4. flour of pumice25. The design of a framework is such that lingual rest seats must be placed on incisor teeth, yet dentin will knowingly exposed in preparing acceptable rest seats. What are the options for providing adequate rest seats on incisors. The rest can be built into a cast veneer crown, 3/4 crown, inlay, laminate veneer, composite restoration, or etched metal restoration. Individually cast chromium cobalt alloy rest seat forms that are attached to the lingual surfaces by composite resin cement can also be used. Sapphire ceramic ortho brackets have also been bonded to the lingual surfaces of mandibular canines and shaped as rest seats.26. The adequacy of a lingual rest seat is better accomplished with a cast restoration than a preparation confined to enamel. True or False? TRUE27. Four conservative alternatives to forming rest seats on teeth with unacceptable lingual contours were described in the text. What are they and what are their advantages and disadvantages. see question 2528. Describe the contour of an incisal rest seat preparation rounded notch form at incisal angle of a canine or incisal edge of an incisor with the deepest portion of the prep apical to the incisal edge. the notch should be beveled both labially and lingually. Page 77 has some great diagrams of the incisal rest. Might be worth checking out cuz it seems a bit different than what we were taught.29. What are the minimum acceptable dimensions of an incisal rest seat 2.5 mm wide, 1.5 mm deep30. Name and describe several indications for the use of incisal rests tooth morphology doesnt permit other designs (ie lingual rest), restore defective or abraded tooth anatomy, provide stabilization, full incisal rests can restore or provide anterior guidance31. Which rest is the most unfavorable in relation to a possible tipping of the tooth. Which is the most favorable to avoid unfavorable leverage factors incisal and occlusal of molar or premolar respectively32. For what reasons must a rest restore the occlusal, lingual, or insical morphology of the abutment tooth that existed before the rest seat preparation Im starting to feel like an idiot-cant find this one either!!! Will let you know asap :0)
Chapter 8: Indirect Retainers1) What elements prevent movement of the base of a tooth-supported denture toward thebasal seats? -- Occlusal, lingual or incisal rests.2) Support of a distal extension removable partial denture is shared by abutment teethand residual ridges. The quality of support furnished by the residual ridges isproportionate to at least three factors. Name them. --(No clear answer in ch 8) 1. Length of distal extension base. 2. Location offulcrum line. 3. How far beyond the fulcrum line the indirect retainer is placed. Improper use of any of the above factors will increase the pressure on the residual ridges.3) Movement of a distal extension base away from basal seats will occur as a rotationalmovement or as ______. --?. Horizontal maybe4) What is the difference between fulcrum line and axis of rotation? --None. The axis of rotation of a denture is about the fulcrum line.5) Identify the fulcrum line on class I arch; class II mod.1; class IV. -- class I: Line between two most posterior teeth. Ideally the mesial of 2ndpremolars. -- class II mod. 1: Diagonal line passing through abutment on distal extensionside and most posterior abutment on opposite side. -- class IV: Line passes through two abutments adjacent to single edentulousspace.6) Define Indirect Retainer. -- The rigid components of the denture framework that are located on definiterests on the opposite side of the fulcrum line away from the distal extension base.7) What components of a removable partial denture usually make an indirect retainer? -- One or more rests and supporting minor connectors. Proximal plates adjacentto edentulous spaces.8) From the standpoint of leverage advantage, where should an indirect retainer belocated? -- As far away from the fulcrum line as possible at right angle to fulcrum line.9) An indirect retainer performs one major function and four auxiliary functions. Namethem. -- Major: Activate the direct retainer to prevent movement away from the tissue. -- Minor: 1) Reduce anteroposterior tilting leverages on the principle abutments. 2) Stabilize against horizontal movement by contacting axial surfaces. 3) Anterior teeth supporting a indirect retainers are stabilized against lingualmovement. 4) Act as auxiliary rest to support portion of major connector. This helpsdistribute stress. 5) Provide first visual indication for need to reline and extension base partial.Dislodgement of indirect retainers indicates deficiencies in basal seat support.10) The effectiveness of indirect retainers is influenced by four factors. Name them. 1) Principle occlusal rests on primary abutments must be reasonably help in their
seats by retentive arms of direct retainers. If rests are displaced from their seats, norotation about the fulcrum line will occur, thus the indirect retainers will not engage. 2) Distance from the fulcrum line. Must also consider; a) Length of the distal extension base. b) Location of the fulcrum line c) How far beyond the fulcrum line the indirect retainer is placed. 3) Rigidity of the connectors supporting the indirect retainer. 4) Effectiveness of the supporting tooth surface. Indirect retainer must be placedon a definite rest seat where no slippage or tooth movement will occur. Tooth inclinesand weak teeth should never be used.11) What are the probable sequelae of trying to use a continuous bar or linguoplate toserve as an indirect retainer? -- Cingulum bars and linguoplates are not indirect retainers because they rest onunprepared lingual surfaces. The terminal rests at either end of the bar/plate are theindirect retainers. If used as an indirect retainer, movement of the teeth can occur (ortho).12) In a class II, mod. 1 arch, especially if the modification is a long endentulous space,what component may act as an indirect retainer? -- The occlusal rest on a secondary abutment tooth. (primary abutments wouldbe adjacent to distal extension base and most distal abutment on tooth supported side.Secondary abutment would be an anterior abutment on the tooth supported side.)13) Discuss the inadequacy of rugae to act as support for indirect retention. -- Often a part of palatal horseshoe design. Not as good as tooth support. Rugaesupport should be avoided when possible.14) True/False: Each design of the extension base-type RPD should include an indirectretainer or some component that will act as an indirect retainer. -- TRUE15) True/False: Bilaterally placed indirect retainers contribute to stability of class Irestoration more so than a single indirect retainer. -- TRUE (Centrals are too weak for an indirect retainer so bilateral premolarretainers are preferred. Closer to fulcrum line [less lever action] but stronger teeth.)Chapter 9 1. What is a denture base? A. Supports the artificial teeth and receives functional forces for occlusion and transfers functional forces to supporting oral structures. 2. What does the term basal seat mean? A. The oral tissues and structures of the residual ridge supporting a denture base. 3. Is the primary purpose of a denture base related to the masticatory function? If so, how? A. Yes. Functional stability for distal extensions is most critical. It must provide the ability to transfer forces without undue movement. 4. Describe how the denture base contributes to the factor of appearance.
A. A base must simulate the natural-looking contours and tinting.5. Are the functions of tooth-supported and extension-type bases somewhat different? If so, how do they differ? A. In a tooth-supported RPD the forces are directed to abutments. Extension- type transfer stresses to soft tisues.6. What are the functions of a tooth-supported partial denture base? A. A span between two abutments supporting artificial teeth.7. Describe the functions of a distal extension partial denture. A. Proved a means to attach denture teeth and dissipate occlusal forces8. The space available for a denture base is controlled by the structures surrounding the space and their movements during function? True or false? A. True9. Explain the snowshoe principle as it applies to denture base design. A. Broad coverage furnishes the best support with the least load per unit area. Providing for maximum support.10. By what means is an acrylic resin base attached to a framework? A. By means of a minor connector designed so that a space exists between tissue and meshwork. Accomplished by nailhead retention, retention loops or diagonal spurs placed at random.11. A ladderlike minor connector is used to attach an acrylic resin base to frameworks. Should this minor connector be regid or flexible? Why or why not? A. Rigid. Provides strength (not 100% sure on this one)12. Is it important and that a minor connector for an extension type of acrylic resin base be located on both the buccal and lingual sides of the residual ridge? Explain. A. Yes, minimize warpage13. Is an open ladder type of design for connecting an acrylic resin base to a major connector preferable to a closed meshwork design? Why? A.14. Give a rule of thumb for how far the minor connector should extend posteriorly. A. Extend buccally within physiologic tolerance of border structures. Mx: cover both Mx tuberosities, extend into the pterygomaxillary notches and provide for adaption along the posterior border, taking care not to extend beyond the soft palate flexure. Mn: bilateral distal extension RPD bases cover the retromolar pads and extend into the retromylohyoid fossae
15. The minor connector for acrylic resin bases must be totally embedded in the acrylic resin base. What thickness of acrylic resin is necessary between the residual ridge and minor connector to allow adjustment of the base if it should become necessary? A. We use 2X28 gage 16. Nine requirements for an ideal denture base are given in this chapter, list six. 1. Accuracy of adaptation to the tissue, with minimal volume change 2. Dense, nonirritating surface capable of receiving and maintaining a good finish 3. Thermal conductivity 4. Low specific gravity; light weight in the mouth 5. Sufficient strength; resistance to fracture or distortion 6. Easily kept clean 7. Esthetic acceptability 8. Potential for future relining 9. Low initial cost 17. Metal bases have distinct advantages over acrylic resin bases, such as thermal conductivity and accuracy and permanence of form. What are the other advantages? A. Can be thinner, easier to keep clean, minimize bulk 18. What are the indications and contraindications for metal bases? A. Metal is thinner, thermal conductivity, strength B. Contras: esthetics, functional tongue and cheek contours 19. Can denture base contours for functional cheek and tongue contact best be accomplished with acrylic resin or metal? Why? A. Acrylic Resin. You can create bulk with out the added weight. 20. Relining of extension bases becomes necessary to reestablish support of the base. Could this be a factor in selecting the material for a denture base? Explain. A. Acrylic resin that can be relined to adjust for changing tissues and demands. Metal cannot. 21. How can it be determined when a denture base requires relining? A. When there is loss of occlusal contact (there may be more?) 22. What is meant by the word stress-breaker in removable partial pros? A. A connection that dissipates vertical stresses (Hinge) 23. By what means can the action of the retaining elements of a stress-breaker be separated from movements of the extension base? A. Allows independent movement of denture base and direct retainers. 24. Stress-breakers may be divided into two broad groups. Give two examples of each group. A. The book wasn’t really clear on this one. There are hinge type and split bar type.Good luck everybody. If anybody has questions on this section drop me an email:email@example.com or call 218-791-0662 CHAPTER 10
1. Nine factors that influence the design of a partial denture: a. tooth or tissue support b. amount of supporting bone c. crown/root ratio d. crown/root morphology e. tooth number and position in arch relative to edentulous space f. presence of residual ridge g. variable tissue support h. functional forces from opposing arch i. opposing arch tooth position different occlusion2. How is the design of a denture influenced by the classification of the arch being restored? The type of arch presents various types of coverage forces and occlusion. RPDs opposing natural teeth will require greater support and stabilization because greater functional load demands3. Two main types of dentures and why? a. Kennedy class I and II-primary support tissue under base, secondary support from abutment teeth b. Kennedy class III- all support derived from abutment teeth4. Refer to book- Essay question5. Definition of Guiding Plane: Two plus vertically parallel surfaces of abutment teeth shaped to direct a prosthesis during placement and removal. They are parallel to path of insertion and preferably the long access of abutment teeth.6. Three main functions of guiding plane surfaces contacted by minor connectors:. a. Provide one path of placement and removal b. Insure intended actions of reciprocal, stabilizing, and retentive components c. Eliminate food traps btn. Abutment teeth and denture7. Should guiding planes on enamel surface of abut teeth be rounded or flat? Why? a. Rounded, to avoid B or Li line angles bc line angles weaken either or both parts of clasp assembly8. Rule of thumb for prox guide planes? a. Half width of distance btn tips of adjacent B and Li cusps or 1/3 B to Li width of tooth9. Direct retainers for tooth supported dentures differ in design from those used in extension base-type dentures. What requirement, in relation to undercut, exists for direct retainer (clasp) on a terminal abut of extension denture when denture base is forced into heavier contact with residual ridge? a. Prevent horizontal movement, allow flex of retentive clasp, clasp arm must be freely flexible in any direction. Round, tapered clasp form offer advantages of more uniform flexibility, less tooth contact, and better esthetics.10. Name component of RPD that must be rigid. Name flexible parts. a. Rigid- Minor connectors that join rests and clasp assemblies to major connector, reciprocal arm clasps b. Flexible- retentive arm clasp
11. Would a fixed partial denture be a better than RPD? a. Totally depends on patient preferences and clinical presentation 12. What method used to replace single missing teeth or missing ant. Teeth a. Preferably bridge, implant, maybe nothing 13. when confronted with K class 1, should you replace premolars with fixed partial? a. No, nothing distal as an abutment 14. Amount of stress transferred to supporting edent ridge and abut teeth in extension based partial are dependent on 4 factors. a. length of lever arm or denture bases b. an anterior placement of indirect retainer c. use lingual plate or bar d. occlusal rest versus cingulum rest 15. Systematic approach to designing RPD. Outline different approaches. (Too Broad) 16. In evaluating potential support abut teeth can provide (K class 1), what specific characteristics of teeth should be considered? a. Crown/ root ratio b. Perio health c. Orientation 17. In eval potential tissue support that edent ridge can provide in extension base situations, what characteristics should be considered? a. Shape and amount of underlying bone b. Amount of gingival soft tissue 18. Supporting units and functional stresses of K class 1 RPD? Vague question. 19. In developing a design for an extension base RPD when does one determine how denture is retained? a. After analyzing undercuts and patient preference 20. How does oneknow if indirect needs to be incorporated into the design? a. Always 21. What is the final step in the proposed systematic approach to design? a. They ask about a systematic approach but it is never explained here, Know different designs and when, where rests / retention placed, indirect retention, eval ridges, etc. 22. What is a splint bar? a. Splint used to connect a double abut for stability between sides of an arch when replacing ant teeth in K class 4. 23. Draw a splint bar. Yeah right. See page159 24. Purpose served by of splint bar. a. See question 22 25. Enough about splint bars. 26. Why must splint bar be convex rather concave adjacent to residual ridges? a. Doesn’t actually say but probably to avoid tissue irration.27.Chapter 10 – Principles of Removable Partial Denture Design(this chapter would be excellent to read before the practical!)
1. The text suggests at least nine factors that will influence the design of a removable partial denture. Please list them. Tooth vs tissue supported Amount of supporting bone Crown/root ratios Crown and root morphologies Tooth number and position in the arch relative to the edentulous spaces For a tooth tissue supported prosthesis-the residual ridge for support Opposing arch tooth positions Existing and nature of prosthesis support in the opposing arch Potential for establishing a harmonious occlusion (this one’s retarded but it makes 9 :0)2. How is the design of a denture influenced by the classification of the arch being restored. The main difference is in the type of support-whether that be tissue, tooth, or tooth-tissue.3. There are really only two types of removable partial dentures. What are they? Kennedy class I / II vs Kennedy class III.4. Because there are two basic types of removable partial dentures, it is evident that a dentist must consider 1) the manner in which each is supported 2) the method of impression registration 3) the need of or lack of need for indirect retention and 4)the use of a base material that can be readily relined. Write a meaningful essay of 100 words or less about each of these listed considerations. The answer to this question is pp 146-148. Kinda helpful.5. What is a guiding plane? Defined as two or more parallel, vertical surfaces of abutment teeth, so shaped to direct a prosthesis during placement and removal6. What are the three main functions of guiding plane surfaces contacted by minor connectors? 1) to provide for one path of placement and removal of the restoration to eliminate detrimental strain to abutment teeth and framework components during placement and removal 2) to ensure the intended actions of reciprocal, stabilizing, and retentive components to provide retention against dislodgement of the restoration when the dislodging force is directed other than parallel to the path of removal and also to provide stabilization against horizontal rotation of the denture 3) to eliminate gross food traps between abutment teeth and components of the denture7. Should guiding planes prepared on enamel surfaces of abutment teeth be rounded or flat, why? The guide planes should be rounded. The reason for this is to avoid creating buccal or lingual line angles that could be produced in flat guide planes. These line angles would weaken the clasp assembly that contacts it.8. Give a rule of thumb for the dimensions of proximal guiding planes Guide planes should be one half the width of the distance between the tips of adjacent buccal and lingual cusps or about one third of the buccal lingual width of the tooth.9. Direct retainers for tooth supported dentures differ in design from those used in extension base type dentures. What requirement, in relation to an undercut, exists for the direct retainer on a terminal abutment of an extension denture when the denture base is forced in to heavier contact with the residual ridge Must be able to flex sufficiently to dissipate stresses that otherwise would be transmitted directly
to the abutment tooth as leverage. Some dentists prefer stress-breakers, others believe wrought wire are the best for this.10. Name the components of a removable partial denture that must be rigid. Name the components in which flexibility is desirable The rigid ones are major connectors, minor connectors and reciprocal clasp arms (the stabilizing components). The flexible ones are direct retainers (retentive clasps) in tooth supported and for distal extensions partial dentures.11. Would you agree that a fixed partial, where indicated, should be the restoration of choice, in lieu of a removable partial? Give an example and explain. Sorry, my clinical judgment at this point is a little lacking. The book doesn’t answer this question and I guess I’ll email this to Dr Olin. My guess is this question is just trying to make the point that each situation is going to be different depending on the health of the remaining teeth, the patient (ie dexterity, finances, etc), the disease process in the patient (ie rampant caries), etc.12. What method should usually be used to replace single missing teeth or missing anterior teeth? Justify your answer. A fixed partial denture (from chapter 14)13. When confronted with a Kennedy class I arch in which all molars and first premolars are missing, should one consider replacing the first premolars with fixed partials rather than restoring the spaces with a removable restoration? Why? The answer, of course, would be dependent on the clinical situation. However, if the 2nd premolars turned out to be weak abutments on their own, the splinting of the canine and 2nd premolar by a fixed partial denture can provide adequate support for abutment. The answer is yes-the first premolar should be restored by a fixed partial.14. The amount of stress transferred to the supporting edentulous ridges and the abutment teeth in extension base partial dentures is dependent on four factors. One is the length of the lever arm or denture bases. Identify the other three and describe how each influences this stress transfer. 1) direction and magnitude of the force 2) the quality of resistance (support from the remaining natural teeth and edentulous ridge) 3) the design characteristics of the partial denture.15. A systematic approach to developing the design for any removable partial denture was presented and discussed. Outline the steps presented in this approach. 1) determine how the partial denture is to be supported (ie rests and tissue stops) 2) connect the tooth and tissue support units (ie major and minor connectors) 3) determine how the rpd is to be retained (ie clasps) 4) connect the retention units to the supporting units 5) outline and join the edentulous area to the already established design components16. In evaluating the potential support that abutment teeth can provide, what specific characteristics of the teeth should you consider? 1) periodontal health 2) crown and root morphologies 3) crown to root ratio 4) bone index area 5) location of the tooth in the arch 6) relationship of the tooth to other support units aka length of the edentulous span 7) the opposing dentition17. In evaluating the potential tissue support that the edentulous ridges can provide in extension base situations, what specific characteristics should be considered 1) the quality of the residual ridge 2) the extent to which the residual ridge will be covered by the denture base 3) the type and accuracy of the impression registration 4) the accuracy of the denture base 5) the design characteristics of the component parts of the partial denture framework 6) the anticipated occlusal load
18. In developing the design for an extension base rpd, what component parts are used to connect the supporting units? What specific characteristics should each of these components have to effectively distribute functional stresses to the supporting units? Major connectors should be properly located in relation to gingival and moving tissues and should be designed to be rigid. Rigidity in a major connector is necessary to provide proper distribution of forces to and from the supporting components. Minor connectors should be located in interproximal spaces to provide adequate bulk of material without impinging on the tongue.19. In developing a design for an extension base rpd, when does one determine how the denture is to be retained? What are the keys to selecting successful clasp designs Retainers for distal extension rpds have to be able to flex or disengage when the denture base moves toward the tissue when in function. Thus, the retainer may act as a stress breaker. Clasps that act as stress breakers, rather than a mechanical stress breaker, provide the same stress relief without compromising the horizontal stabilization of the rpd. The clasp must be freely flexible in all planes-rounded tapered clasps are the best. Therefore, the wrought wire circumferential or a carefully designed bar clasp can be used.20. How does one know if indirect retention needs to be incorporated into the design? If needed, where should it be located, and what component parts would be included in the design to serves as indirect retainers? Indirect retention is placed in situations where a fulcrum line exists. Fulcrum lines exist only where a distal extension is present (ie no fulcrum line exists in a kennedy class III-Dr. James said this is a classis test question). Indirect retention should be placed as far anterior (and at a right angle) to the fulcrum line, on a tooth that is capable of withstanding the forces placed on it. Therefore a canine or premolar should be used. An incisal or cingulum rest seat should be used. This describes the first purpose of indirect retention-to prevent rotation of the rpd about the fulcrum line. The second purpose of indirect retention is in support of the major connector- for example, a long lingual bar can be prevented from settling into the tissue if indirect retention is incorporated. Remember-a lingual plate is not an indirect retainer, it is located on inclined tooth surfaces which make it an ortho appliance.21. What is the final step in the proposed systematic approach to design? Should this design characteristic have any special requirements? If so, what are they? The final step was to outline and join the edentulous area to the already established design components (see question 15). The amount of flexure of the distal extension will affect the retentive clasp requirements. For example, if the edentulous ridge is greatly resorbed, the span is especially long, or excessive occlusal load is placed on the extension, greater flexure of the clasp will be required. These examples will also be important in considering how the minor connector will contact the abutment tooth adjacent to the extension in order to prevent torque on that abutment tooth. There is a good diagram on page 149 explaining this phenomenon that is difficult to explain in words.22. What is a splint bar? As answered in a previous question-missing anterior teeth are best replaced with a fixed partial. However, some situations exist in which several missing anterior teeth need to be replaced with the rpd (ie replacing a long span of anterior teeth). When this is the case-the splint bar acts as the major connector to connect the abutment teeth in a long span in order to provide support to the replaced anterior teeth. There is a good picture on page 159 to get an idea of what it looks like.23. Draw a splint bar from a frontal, horizontal, and sagittal view. Label the dimensions and relationship of the bar to the tissue and the abutments. The splint bar should be round or ovoid. As viewed from above, the splint bar should be in a straight line between the abutments. In a sagittal section, a rounded pear shape makes point contact with the ridge (prevents rotational torque). The bar should be placed slightly lingual to the ridge to provide esthetic arrangement of the artificial teeth.
24. What purposes are served by use of splint bars where indicated? Enhances longevity of the teeth being replaced and stability of the rpd. Basically, just think of it as a sturdy structure for a long span of artificial teeth to rest on. If flexure of the long span occurs, this prevents the fracture of the span. Kinda like a sturdier grid work that is between two abutments.25. A decision has been made to use a splint bar from canine to canine. Will this decision influence the design of the framework? If so, how? The major design difference in using a splint bar is that the bar actually serves as the major connector, so the traditional major connector is not needed.26. For what reasons must a splint bar be convex, rather than concave, adjacent to the residual ridge? The splint bar needs to be concave in order for the patient to be able to keep it clean (flossing). Think of the hygienic pontic we learned about-same principles.27. Is a 13 guage splint bar adequate for a span from canine to canine? Why or why not? NO-long spans require more rigid bars (10 guage)28. Describe and define an internal clip attachment The internal clip attachment differs from the splint bar in that the internal clip provides both support and retention from the connecting bar. See figure 10-17 on page 161 for picture. Basically, a connecting bar is placed (for example) between two canines and is raised slightly off of the edentulous ridge. Then, a nylon or metal ‘clip’ is secured in the tissue contacting side of the rpd. The clip is contoured to fit the bar and kinda snaps around the bar. The use of the bar and clip provides support, stability, and retention for the anterior modification area and it may allow one to eliminate both occlusal rests and retentive clasps on the adjacent abutment teeth.29. The internal clip attachment must be used in conjunction with some type of bar supported by abutment teeth. What is the cross-sectional shape of such a bar? What advantages accrue from using such a design for a restoration? The previous question answered this one except that the bar should be round and straight in order for the clip to be able to engage it.30. You are confronted with a mandibular arch with only the six anterior teeth and two second molars remaining. The maxillary arch is edentulous. The anterior teeth are restorable individually and show no mobility or periodontal involvement. The molars, however, are grossly involved with caries, in fact most of the clinical crown is gone. They also show a Miller mobility classification of 1 and exhibit a 5 to 6 mm gingival crevicular depth. They can be treated periodontally and endodontically. In such a situation, if finances were not a factor, would you 1) extract both molars 2) prepare the molars for an overlay prosthesis 3) extract all the mandibular teeth and treat the patient with complete dentures? Every consideration should be directed at preventing the need for a distal extension. In this situation, one would prepare the molars for an overlay prosthesis. If teeth can be endo treated, perio treated, and have not tipped (ie from opposing occlusion), they can serve as abutments. The tooth is prepared in a way that it ends up as a slightly elevated (just slightly above the tissue) dome shaped abutment for which the rpd will engage. This eliminates the need for a distal extension.31. If the molars mentioned in the preceding section were prepared for an overlay prosthesis, state the reasons for doing so in terms of benefits to the patient. This eliminates the need for the distal extension and problems that go along with the distal extension (ie more torque on the abutment teeth, pressure placed on the residual ridge, etc.)
Chapter 11: Surveying1) Define a dental cast surveyor. An instrument used to determine the relative parallelism of 2+ surfaces of teeth or other parts of the cast of a dental arch.2) What are the basic parts of a surveyor? -Platform on which the base is moved -Vertical arm that supports superstructure -Horizontal arm from which surveying tools suspend -Table to which the cast is attached -Base on which the table swivels -Paralleling tool or guidance marker (contacts the convex surface of the tooth) -Mandrel for holing special tools3) What does the height of contour mean? How does is relate to a direct retainerassembly? Height of contour – line encircling a tooth, designating its greatest circumference at a selected position determined by a surveyor. The height of contour determines the location of non-retentive reciprocal and stabilizing arms and the location of retentive clasp terminals.4) Because no component of a removable partial denture may engage an undercut excepta portion of the retentive arm of a direct retainer, then both desirable and undesirableundercuts must be known in deigning a restoration. True or False? True5) When planning the design of a partial denture, 4 factors must be considered indetermining the path of placement and removal. Two of these factors are retention andesthetics. Name the 2 other factors. Guiding planes and Interference6) With the diagnostic cast securely clamped to the adjustable table and the diagnosticstylus in the vertical spindle, what orientation of the occlusal plane to the base of thesurveyor is recommended as a provisional study position? The occlusal surfaces are approximately parallel to the platform.7) When considering a design for a class III, modification 1 arch, which directional tilt ofthe cast will indicate the greatest area of parallel proximal surfaces to act as guidingplanes – anteroposterior or lateral? Anteroposterior8) Suppose in the previous situation, that the diagnostic stylus touches only gingival areasof the proximal surfaces. What are the options to obtain guiding plane surfaces? In making the choice btw. having contact with a proximal surface at the cervical area only or at the marginal ridge only, contact at the marginal ridge is preferred
b/c a plane can be established by recontouring. When only a gingival contact exists a restoration in the only means of establishing a guiding plane.9) When possible retentive areas are being ascertained, the cast is tilted laterally. Howcan one avoid changing the established anteroposterior tilt of the cast? Rotate it about an imaginary longitudinal axis with out disturbing the anteroposterior tilt already established.10) Uniformity of retention bilaterally is desirable. In what manner does the angle ofcervical convergence contribute to obtaining uniform retention? The amount of retention existing below the height of convexity may be determines by observing the angle of cervical convergence and tilting the cast laterally until similar areas of retention exist on the principal abutment teeth.11) What are the most common causes of interference to the placement of a mandibularmajor connector? Bony prominences and lingually inclined premolars are the most common causes of interference to a lingual bar connector.12) Why should soft tissue contours be surveyed along with teeth? Bony undercuts may interfere with seating of the denture base. An undercut may also leave too large of a gap for the minor connector of an I-bar which would leave objectionable spaces and trapping of food.13) What advantages accrue in having the tip of the carbon marker touch the gingivalareas intermittently when marking the heights of contour of abutment teeth? To ensure that you are not recording a false height of contour and that the carbon marker is reaching the height of contour. (this was not in the book, I asked Dr. Madden if he knew the answer – Dr. Olin was gone that day – and he did not know the answer either, so this is just my best guess. I’m sending an email to Dr. Olin to ask, when he responds I will let you all know.)14) After the diagnostic cast has been surveyed, how can the relationship of the cast tothe vertical spindle of the surveyor in three dimensions be recorded? There are two methods: - Tripoding: Place three widely divergent dots on the tissue surface of the cast using the tip of a carbon marker, with the vertical arm of the surveyor in a locked position. Preferably these dots should not be placed on areas of the cast involved in the framework design. The dots should be circled with a colored pencil for easy identification. - Score two sides and the dorsal aspect of the base of the cast with a sharp instrument held against the surveyor base. By tilting the cast until all three lines are again parallel to the surveyor blade, the original cast position can be reestablished. Scratch lines will be reproduced in any duplication, thereby permitting any duplicate cast to be related to the surveyor in the a similar manner.
15) What is the disadvantage of using a carbon marker that is even slightly worn? A worn (tapered) carbon marker will indicate heights of contour more occlusally located than they actually exist.16) What is an undercut gauge? How can it be used to measure the depth of undercut inthe angle of cervical convergence? An undercut gauge is an attachment to the surveyor which measures the amount of undercut in hundredths of an inch. To use the undercut gauge, place the vertical portion of the gauge against the height of contour on the axial surface of the tooth and the edge of the horizontal portion against the axial portion of the tooth below the height of contour so that both are touching at the same time. This will allow you to determine where you have the desired amount of undercut and it can be mark on the cast to aid in the design of clasps. (Disclaimer: This answer was not in the book so this is just my own answer that I came up with.)17) Heights of contour in many instances will be more optimally located for directretainer assemblies if axial surfaces are recontoured. How may an undercut gauge assistin determining whether they can be recontoured without exposing dentin? The undercut gauge allows you to determine how much tooth structure would need to be removed in order to achieve the proper contour and undercut.18) Diagnostic cast are quite often altered during design on the surveyor or in other uses.Why is it a good idea to have duplicate casts? So that if you begin designing an RPD on one cast and it doesn’t work, you have another unaltered one to work with, without having to bring the patient back in for another impression. Also it may be nice to have a cast that has not been altered so you can see what the original arch looked like before alterations. (I did not find this answer in the book this is just my guess using logic)19) The designed diagnostic cast can readily serve as a blueprint to accomplishcontouring of abutment teeth during mouth preparation procedures. How may thecontoured areas on the diagnostic cast be indicated to avoid overlooking these areas whenpreparing them in the mouth? All proposed mouth changes should be indicated on the diagnostic cast in red pencil, with the exception of restoration to be done. These mouth changes include: preparation of proximal surfaces, reduction of buccal and lingual surfaces and preparation of rest seats (rest seats should always be deferred until all other mouth preparations have been completed).20) After mouth preparation procedures are completed and a mast cast has been made, itmust be surveyed to definitively locate components. What are the guides to relate thecast to the surveyor? The prepared proximal guiding plane surfaces will indicate the correct anteroposterior tilt. The lateral tilt will be the position that provides equal retentive areas on all principal abutments in relation to the planned clasp design.