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Removable Partial Dentures 101Removable Partial Dentures 101Back to the BasicsBack to the Basics

Luther A. Ison, CDTLuther A. Ison, CDT

University of Minnesota School of DentistryUniversity of Minnesota School of Dentistry

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Anterior-Posterior Palatal Strap Major connector

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Lingual Bar Major Connector, Kennedy Class II

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Palatal Strap Major connector

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Dr. Nobels vulcanite/wrought wire partial

fabricated as second year dental student in 1940.

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Lingual bars dont touch tissue. 1x28 gauge relief wax

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R.P.D. = VariationR.P.D. = Variation

Survey / Path of Insertion / DesignSurvey / Path of Insertion / Design

RetentionRetention

Guide PlanesGuide Planes

RestsRests

Major ConnectorMajor ConnectorMinor ConnectorsMinor Connectors

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Survey and design. Whose responsibility is it?

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Good old communication; aint it great!

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Retentive undercuts on both sides of the arch arefirst requirement of Removale Partial Denture.

Changing the tilt will raise one side and lower theopposite side.

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Three Tripod Marks, circled in red, well

separated, and all in the same horizontalplane.

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RetentionRetentionSuprabulgeSuprabulge

AkersAkersP.G.P.P.G.P.

Reverse AkersReverse Akers

EmbrasureEmbrasure

InfrabulgeInfrabulge I BarI Bar

Y ClaspY Clasp

Modified Y ClaspModified Y Clasp

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Akers clasp assembly. Buccal retentive clasparm, lingual reciprocation(bracing) and mesialocclusal rest.

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I-Bar clasp assembly with retentive I-bar properlypositioned slightly to the mesial of center of tooth.

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Lingual Plate Major Connector

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Compromised RPD design trying to accommodateretention of tooth #13. Too much stress placed on#13 and #11 under function.

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Teeth adjacent to free-end distal extensions takemore force under function, and require moreflexibility. P.G.P. wire clasp or RPI design may havebeen a better choice for #3.

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Ideal Crest of Cenvexity is at the Junction

of Cervical & Middle Third. WHY?

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.010 Undercut gauge indicating area of retention.

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Red mark indicating where the I bar will contact thetooth ( from 0.0 to .010). No tissue contact.

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I-Bar clasp only conntacts the tooth from thesurvey line to .01 undercut.

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etentive clasp arms must be occlusal to survey line

ntil terminating 4 mm engage the undercut.

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Bracing / ReciprocationBracing / ReciprocationBracing ArmBracing Arm

Bracing PlateBracing Plate

Combination Occlusal Rest & Guide PlaneCombination Occlusal Rest & Guide Plane

(R.P.I.)(R.P.I.)

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Bracing arms and plate contact teeth occlusal tosurvey line.

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Lingual Plated Reciprication/bracing.

Mesial rest on # 28 providesindirect retention

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Akers Clasp Assembly

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I-Bar with lingual plate reciprocation & distal guideplane

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R.P.I. bracing Mesial rest + Distal Guide Plane

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Guide PlanesGuide Planes

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Proper blockout for guide planes.

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Surveying Guide Plane.

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Temporary removable partial denture. Acrylic left in

proximal undercuts will prevent denture from seatingin the mouth.

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Distal Guide Plane

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Occlusal Rests

-Support

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Occlusal Rest may be a little deep

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Rigid bracing arm and external acrylic finish line

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Minor Connectors

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Proper denture tooth esthetics should not be

compromised by poor partial design. This showswhat wed like the tooth to look like.

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Improper minor connector of I-bar compromisessetting of denture tooth. Move connector distally toembrasure. (Framework technician not

communicating with denture dept.)

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Major Connectors

Inadequate room for Lingual Bar Should have been

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Inadequate room for Lingual Bar. Should have been

lingual plate.

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Lingual Bar Major Connector requires 4 mm spacefrom gingival margin to superior part of bar. Floorof mouth requires 3 mm space from frenum to

inferior portion of bar.

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Lingual Plate Major Connector. P.G.P. Clasps

Li l B d t t h th ti 1 thi k

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Edges of saddle relief form internal finish lines. Note tissue stop

and that saddle relief starts 1 mm from teeth.

Lingual Bars do not touch the tissue. 1 thickness

of 28 gauge relief provides the space necessary.

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Fit, finished and polished framework with clasps adjusted.

PGP clasps would have been more passive on abutments.

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11 mm minimum space requirement for lingual bar =

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lingual plate for this case for proper strength andperiodontal health.

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Study/Design/ custom tray cast on left shows plenty of

space for lingual bar. Master cast on right showslingual was not impressioned to full extension. Alteringpartial design in place of reimpressioning isunacceptable.

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Lingual bar positioned too close to teeth. Probably

should have been lingual plate.

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