RPD Manual 11 - Removable Prosthodontics - Dalhousie University

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Rests and Rest Seat - 31 Round Lingual Rest Seat Form Round rest seats are occasionally prepared on the mesial of the canine teeth when the use of a typical cingulum rest is contraindicated (i.e. large restoration, lack of clearance with the opposing teeth, poorly developed cingulum). These rest seats are prepared spoon shaped, similar to an occlusal rest seat, with reduction of the mesial marginal ridge. However, preparation is more difficult due to the incline of the lingual surface of the canine and more tooth structure must often be removed. Round lingual rest seats can be easily incorporated into crowns where there is usually sufficient linguo-proximal reduction, without the problem regarding exposure of dentin. Use care to ensure that no undercuts are prepared in relation to the path of insertion if a round bur is used. 3. Incisal Rests Incisal rests are inferior to lingual rests both mechanically and esthetically. Normally they should not be used unless it is impossible to place a lingual rest seat or a composite bonded rest seat. a. An incisal rest seat is usually placed on the mesio- or disto-incisal angle of the incisor teeth with the deepest portion towards the centre of the tooth. It is predominantly used as an auxiliary rest or an indirect retainer. b. It is usually used on the mandibular incisor where the lower lip can cover, as much as possible, the metal of the rest that shows at the incisal edge. Mechanically, a lingual rest is preferable to an incisal rest, because the lingual rest is placed nearer to the center of rotation of the tooth and therefore, will have less tendency to tip the tooth.
Major Connectors - 32 Definition Major Connectors The unit of a removable partial denture that connects the various parts of the denture. Its principal functions are to provide unification and rigidity to the denture. Functions of a Major Connector 1. Unification A major connector units all other components of a partial denture so that the partial denture acts as one unit. 2. Stress Distribution By unifying all elements of a partial denture the major connector can distribute functional loads to all abutment teeth, so that no one abutment is subjected to extreme loading. Unification of the direct retainers with the denture bases aids in distributing forces between both the teeth and the mucosa. This is particularly important in Class I and II partial dentures. In some maxillary cases a major connector with broad palatal contact is selected. In these situations the broad base offers additional support, distributing stress over a larger area. 3. Cross-Arch Stabilization (Counterleverage) By uniting one side of the arch to the other bracing elements on one side of the arch can aid in providing stability to the other. This can aid in dissipating twisting and torquing forces. Requirements of a Major Connector 1. Rigidity Rigidity is necessary to ensure that the partial denture functions as one unit. If the denture flexes, stress distribution and cross arch stabilization can be compromised since different portions of the denture can move independent of the others. A major connector can be made more rigid by: a. using a more rigid alloy (Chrome-cobalt > gold alloys; cast > wrought metal) b. using a 1/2 round or 1/2 pear shaped bars (more rigid than flat bars) c. increasing the bulk as the length increases d. corrugating linguo-plate or rugae areas. 2. Non-Interference with the Soft Tissues Major connectors should not enter into undercut areas unless tissue impingement can be avoided by changing the selected path of insertion or by using minor undercut blockout. In addition, connectors should not end on the crest of rugae or at the free gingival margin. If terminated in these areas, it is possible that movement of the connector could cause tissue
Page 1 and 2: Removable Partial Denture Manual Ro
Page 3 and 4: Table of Contents Table of Contents
Page 5 and 6: Table of Contents -iii Principles o
Page 7 and 8: Table of Contents - 2 4. poor progn
Page 9 and 10: Table of Contents - 4 F. Classifica
Page 11 and 12: Anatomy Tour - 6 Anatomy Tour for C
Page 13 and 14: Anatomy Tour - 8 ! Soft Palate ! Vi
Page 15 and 16: Anatomy Tour - 10 OTHER STRUCTURES:
Page 17 and 18: Preliminary Impressions - 12 6. Wra
Page 19 and 20: Surveying, Path of Insertion, Guidi
Page 29 and 30: Rests and Rest Seats - 24 A. Defini
Page 31 and 32: Rests and Rest Seats - 26 (d) The f
Page 33 and 34: Rests and Rest Seats - 28 Correct P
Page 35: Rests and Rest Seats - 30 2. The in
Page 39 and 40: Major Connectors - 34 3. Position -
Page 41 and 42: Major Connectors - 36 B. Full Palat
Page 43 and 44: Minor Connectors - 38 Definition Mi
Page 45 and 46: Minor Connectors - 40 The junction
Page 47 and 48: Minor Connectors - 42 When the dent
Page 49 and 50: Direct and Indirect Retainers - 44
Page 65 and 66: Denture Bases - 60 Advantages: Bead
Page 67 and 68: Denture Bases - 62 of the natural d
Page 69 and 70: Principles of Partial Denture Desig
Page 77 and 78: Design Session - 72 Classification
Page 85 and 86: Clinical Protocol, Final Impression
Page 87 and 88:
Clinical Protocol, Final Impression
Page 89 and 90:
Framework Adjustment - 84 Removable
Page 91 and 92:
Framework Adjustment - 86 3. Silico
Page 93 and 94:
Framework Adjustment - 88 after adj
Page 95 and 96:
Jaw Relations, Altered Cast Techniq
Page 97 and 98:
Jaw Relations, Altered Cast Techniq
Page 99 and 100:
Interim Removable Partial Dentures
Page 101 and 102:
Coordinating Fixed and Removable Pr
Page 103 and 104:
RPD Checklist - 98 7. Abutment Modi
Page 105 and 106:
RPD Checklist - 100 16. Baseplate a
Page 107 and 108:
Summary of Design Principles for Re
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RPD Manual 11 - Removable Prosthodontics - Dalhousie University

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