RPD Manual 11 - Removable Prosthodontics - Dalhousie University

Summary of Design Principles for Removable Partial Dentures -- 103
Summary of Design Principles for Removable Partial Dentures
Direct Retainers
- Kennedy Cl III & IV (Tooth Borne)
- – Clasp of choice: cast circumferential
- if can’t use cast circumferential next to edentulous space, use double embrasure clasp
- if abutment is severely tilted use (depending on location of undercut):
! Cast circumferential clasp with lingual retention
! Ring clasp with support strut
! Rotational path removable partial denture
- Kennedy Cl I & II (Tooth & Tissue Borne)
- For posterior abutments, or any tooth needing stress release:
- Clasp of choice: RPI (mesial rest, distal proximal plate and I-bar)
- If can’t use an I-bar in vestibule, because of
! frenum
! shallow vestibule
! deep soft tissue undercut
then use an RPA retainer (mesial rest, distal proximal plate and wrought wire clasp [Akers])
- If can’t use a mesial rest because of:
- rotation
- heavy centric contact on mesial
- - large amalgam restoration on mesial
- then use Combination Clasp (distal rest, buccal ww retention, lingual bracing)
- for abutments adjacent modification spaces (use tooth borne retainers)
- # of direct retainers –, minimum of 2 posterior abutments for Cl. I & II, all abutments for Cl III, IV to
maximum of 4 normally
- if eliminate a direct retainer for esthetics, plan more retention with other features (soft tissue coverage, longer
guiding planes, etc)
Mandibular Major Connectors
Lingual Bar whenever possible (less tissue coverage - hygiene)
Lingual Plate if:
- high floor of mouth
- tori
- frenum
- terminate at FGM
Tissue relief – mandibular major connector (29-30 gauge relief) to avoid tissue impingement
Maxillary Major Connectors
No tissue relief
Tooth borne (Class III & IV): Palatal Strap
Tooth & Tissue borne (Class I & II):
A-P Strap whenever possible
– better sensation, preferred (minor salivary glands & taste buds)
Full Palatal Strap
- periodontal involvement of abutments
- less than 6 teeth left
- displaceable mucosa (increased coverage
Anterior Strap (Horseshoe) – only if inoperable torus is present
– NEVER for Class I or II
Other Principles of Design:
Design drawings – absolute accuracy
- RED – wrought wire, undercut position, circled tripod marks; BLUE – everything else