TYPES OF CROWN &

BRIDGE

Dr Yumna Shaheen Ali

CROWN

DEFINITION OF CROWN

An artificial replacement that restores missing

tooth structure by surrounding part or all of

remaining tooth structure with a material

such as metal, porcelain or combination of

materials such as metal and porcelain.

DIFFERENT TYPES OF CROWNS

Anterior complete crowns for vital teeth

Anterior complete crowns for root filled teeth

Posterior complete crowns

Posterior partial crowns

A) ANTERIOR COMPLETE CROWNS FOR

VITAL TEETH

I. Ceramic Crowns

II. Metal Ceramic Crowns

III. Other types of Crowns

I) CERAMIC CROWNS

Most esthetically pleasing

No metal to block light transmission

Can be virtually indistinguishable from

unrestored teeth

ADVANTAGES

Highly aesthetic and high strength materials

Resist plaque accumulation.

Relative brittleness can be regarded as an

advantage specially in class 2 div I patients

where crown is most likely to fracture rather

than root.

DISADVANTAGES

More tooth reduction

Brittleness, in most cases is a disadvantage

INDICATIONS

Where there are high aesthetic demands.(particularly in incisal area)

CONTRAINDICATIONS

Where more conservative restoration can becarried out.(same for all crowns)

Providing a shoulder of 1 mm would compromise support.(it should be of 2mm)

II) METAL CERAMIC CROWNS

Dental porcelain can be bonded to a variety of

metal alloys such as Gold, Silver, nickel etc

ADVANTAGES

High strength.

Adequate tooth reduction can be done onpalatal side in teeth which are severelyworn by erosion.

DISADVANTAGES

As crown is stronger than natural dentaltissues so an accidental blow can result infracture of root.

To achieve aesthetics margin is oftenplaced subgingivally, causing periodontalproblems

INDICATIONS

Aesthetics

Can serve as a retainer for fixed dental

prosthesis due to its metal substructure.

CONTRAINDICATIONS

Active carious lesions & perio problems.

Young patients with large pulp chambers.

III) OTHER TYPES OF CROWNS

Cast metal crowns with acrylic or composite

facings.

Fibre-reinforced composite crowns.

B) ANTERIOR CROWNS FOR ROOT FILLED TEETH

Composite core & crown

Post and core & separate crown

One-piece post crown

Other types (composite or metal-ceramic

crown retained by pins)

C) POSTERIOR COMPLETE CROWNS

I. Cast metal crowns

II. Metal-ceramic crowns

III. Ceramic crowns

I) CAST METAL CROWNS

Traditionally a GOLD Alloy is used for posterior

metal crowns but because of high cost many

alternative alloys are introduced containing

less gold and in some cases none.

ADVANTAGES

Greater retention and resistance

Less tooth preparation required.

DISADVANTAGES

Poor esthetics

INDICATIONS

Tooth with extensive coronal destruction

On short clinical crowns

Where maximum retention and resistance

is required

CONTRAINDICATIONS

High aesthetic need

II) METAL CERAMIC CROWNS

Advantages

Principal advantage is theirappearance.

Porcelain can be used onbuccal and occlusal surfacesof lower teeth and reverse istrue for upper jaw.

Disadvantages

In short clinical crowns therecomes a problem of retention.

With an amalgam core greaterreduction may expose thepins.

INDICATIONS

Aesthetics

Retention and resistance required

CONTRA INDICATIONS

Active carious lesions & perio problems.

Young patients with large pulp chambers.

III) CERAMIC CROWNS

ADVANTAGES

Reasonable to use with a post

and core

Better appearance then a metal

ceramic crown

DISADVANTAGES

More tooth preparation is required

INDICATIONS

Aesthetic

CONTRAINDICATIONS

Providing a shoulder of 1 mm would

compromise support.

D) POSTERIOR PARTIAL CROWNS

I. Three-Quarter Crowns

II. Seven-Eighths Crowns

I) THREE-QUARTER CROWNS

They cover four-fifthof the tooth’s surface,buccal surfaceremains intact.

They are retained bygrooves on mesial,distal and occlusalsurfaces.

They are alwaysmade of cast metal.

II) SEVEN EIGHTH CROWNS

Covers all but mesial buccal cusp of an

upper molar tooth.

Retained by intracoronal features or

adhesive techniques.

ADVANTAGES

More conservative

Possible to test vitality of tooth via buccal

surface.

Periodontal problems are less.

DISADVANTAGES

Preparation is bit difficult

Less retention

INDICATIONS

Teeth with sufficient bulk

Can be used for retainers for fixed partial

denture, bridge or spring cantilever design.

CONTRAINDICATIONS

Malpositioned teeth

Short clinical crowns

Teeth that are thin bucco-lingually

BRIDGES

DEFINITION OF BRIDGE

Any dental prosthesis that is luted, screwed or

mechanically attached to natural teeth, tooth

roots and/or implant abutments that furnish

primary support for dental prosthesis.

MATERIALS FOR CONSTRUCTION OF BRIDGE

WORK

Metal

Metal-ceramic

All-ceramic

acrylic

DIFFERENT TYPES OF BRIDGES

Fixed fixed

Fixed movable

Cantilever

Spring cantilever

A) FIXED FIXED BRIDGE

Has rigid connectors at both ends of pontics

which forms a rigid prosthesis.

ADVANTAGES

Provides cross arch splinting.

Ease of handling

DISADVANTAGES

Possible bending of bridge

Mobility of abutments may result in open

margins

All units have to be cemented simultaneously

B) FIXED MOVABLE BRIDGE

It has a rigid connector usually at the distal end

of the pontic & a movable connector that

allows some vertical movement of the mesial

abutment tooth.

ADVANTAGES

Allows flexure of mandible

Allow units to be cemented as individual

sections.

DISADVANTAGES

More space required

Metal may show occlusally

Wear of joints

C) CANTILEVER BRIDGE

It’s a kind of minimal preparation bridge.It

provides support for the pontic at one end

only. The pontic may be attached to a single

retainer or two or more retainers splinted

together.

e.g: maryland bridge, rochette bridge

ADVANTAGES

Preserve tooth structure

Minimal pulp trauma

Rebond possible

DISADVANTAGES

Length of span is limited to one pontic only.

Occlusal forces on the pontic encourage

tilting of abutment tooth.

Not successful for posterior prosthesis.

D) SPRING CANTILEVER BRIDGES

They are restricted to the replacement of

upper incisor teeth. Only one pontic could be

supported by a spring cantilever bridge.

ADVANTAGES

Restoration of spaced dentition

DISADVANTAGES

Food impaction under metal connector

Fracture of metal connector

Dislodgment of retainer