major connectors

5/24/2018 Major Connectors

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Major Connectors


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Functions of a Major Connector

Unification

Partial denture acts as one unit

Connects various parts


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Stress Distribution

Distributes functional loads to both

teeth & mucosa


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Cross-Arch Stabilization

(Counterleverage)

Bracing elements on one side of thearch providing stability to the other


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Requirements of a Major Connector

Rigidity

Functions as one unit


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To Increase Rigidity

Use a more rigid alloy

Chrome-cobalt > gold alloys; cast > wrought

Shape

1/2 round > 1/2 pear shaped > flat bars


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To Increase Rigidity

Increase the bulk as the length increases

Corrugate linguo-plate or rugae areas


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Requirements

Non-Interference with Tissues

Should not enter undercut areas

avoid by changing path of insertion

or by using blockout


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Non-Interference With Tissues

Avoid terminating on:

Free gingival margin

Cross abruptly at 90o

Relief is used to minimize

impingement

(Fig 2-17, Stewart's)


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Avoid terminating on:

Hard structures such as the mid-

palatal suture or mandibular tori

Place relief


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Avoid terminating on: Lingual frenum & the movable soft palate

Soft tissue movements must also be allowed

Careful intraoral exam


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Minimize Food Impaction

Locate margins away from the FGM

Eliminate "traps" or large concavities

where food can collect


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Unobtrusive

Smooth transition from connector to

denture base - butt joint


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Unobtrusive

Line angles and edges should be smooth

and rounded

Borders should not interfere with speech



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Mandibular Major Connectors

Lingual Bar

Lingual Plate

Continuous Bar


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Lingual Bar

Most common in mandibe

Use whenever possible


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Lingual Bar

Shape

Flat on tissue side

Convex or tear-drop on

tongue side

(1/2 pear shape, with

thin edge toward teeth)



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Lingual Bar

Size

Occluso-gingival width = 4 to 6 mm

Thickness = l.5 to 2 mm


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Inferior Border Mandible

Patient lifts tongue

Activates floor of mouth

Measure from tip of probe to free

gingival margin


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Inferior Border Mandible

Record values in chart, transfer to cast


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Lingual Bar Position

Superior border

l.5-2.0 mm or more below FGM

As far from gingival margin aspossible



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Potential Impingement

Anterior major connector moves toward tissueas the posterior portion is loaded

Space needed more when ridge is less vertical



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Mandibular Major Connector Relief

Eliminates impingement Wax spacer (relief) placed under major

connector

one thickness of 30 gauge wax


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Lingual Plate (Linguoplate)

Lingual bar with extension over cingula ofanterior teeth

Use where a lingual bar cannot be used


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Lingual Plate Indications

Potential Impingement from lingual bar

High floor of the mouth

Prominent lingual frenum

Lingual tori


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Lingual Plate

Rest at each end of lingual plate

Prevents forces being directed facially

Easier denture tooth addition than bar


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Lingual Plate Variations

May show through embrasures

(Fig 2-41 & 43, Stewart's)


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Continuous Bar Retainer(Kennedy Bar, Double Lingual Bar)

Lingual bar with secondary bar above

cingula

Secondary bar acts as indirect retainer


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Continuous Bar Retainer

Potential food trap between two bars

Normally avoid


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Maxillary Major Connectors

Anterior-Posterior Palatal Strap

Full Palatal Strap

Palatal Strap

Anterior Palatal Strap


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Maxillary Major Connectors

Terminate 4.0 mm or more from free

gingival margin when possible


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Anterior-Posterior Palatal Strap

Maximum rigidity

Minimum bulk

Use in most cases

Especially torus palatinus


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Anterior-Posterior Palatal Bar

A narrow (A-P) variation of anterior-

posterior palatal strap

Double palatal bar connector

Requires greater bulk for rigidity


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Anterior-Posterior Palatal Bar

More objectionable to the patient

Strap connectors provide greater

distribution of stresses


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Full Palatal Plate

Maximum tissue support

Connector of choice in long distal

extension cases

Six or less anterior teeth remain


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Full Palatal Plate

Abutments are periodontally involved

Maximum stress distribution

Flabby tissue

Shallow palatal vault


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Full Palatal Plate

Greater stability and stress distribution

Not used with torus

Increases retention


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Full Palatal Plate

Connector should:

Be fabricated of uniformly thin metal

Have accurate anatomic reproduction

of the ruggae

improves strength and rigidity


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Full Palatal Plate

Connector should:

Cover same area as complete denture

posteriorly

Have large surface area of mucosal contact

improves potential for retention


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Full Palatal Plate

Generally of cast metal

Acrylic resin used in interim prostheses


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Palatal Strap

Usually use for Class III & IV cases

Wide anterio-posteriorly


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Palatal Bar Dont use

Narrow anterio-posteriorly

Thick occluso-gingivally

Palatal bar objectionable due to bulk



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Palatal Strap (or Bar)

Neveruse in cases involving distal extensions orreplacement of anterior teeth since it must be

made bulky for rigidity

Relief may be required over bony midline

Not used with torus


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Anterior Palatal Plate(U-Shaped or "Horse-Shoe" Palatal Connector)

Poor connector

Neveruse unlessabsolutely necessary

Requires bulk in the

rugae area (where

the tongue requires

freedom) for rigidity


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Anterior Palatal Plate

Too flexible

Allows movement at the posterior Traumatic to the residual ridge

Use only where torus prohibits other

connectors


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Flexes, impinging on soft tissue


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Unilateral RPD

Dangerous

Avoidaspiration

major connectors

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