DENTAL INLAY

DENTAL INLAY

• Inlay is a an indirect restoration which is fabricated in the lab and than cemented to the prepared cavity.

DIRECT VS INDIRECT RESTORATION

• In direct filling the material is taken in plastic state into the prepared cavity where it hardens.

• In indirect restoration the hardened filling is cemented into the prepared cavity

DIFFERENCE

AMALGAM RESTORATION

INLAY PREPARATION

Advantages of inlay

• Better physical properties• Clinical longevity• Easier to carve a large restoration to normal

occlusion and ideal contacts• Easy to make guide planes for removable

prosthesis• Easy to alter the occlusion• Aesthetic restoration

Disadvantages of inlay

• Costlier than direct restoration(Gold inlays cost 4-5 times that of a silver amalgam)

• Two visits for the patient• Microleakage, dependent on cement

Types

• Gold inlay• Porcelain inlay• Composite inlay

GOLD INLAY

• ADVANTAGESa) Co efficient of thermal expansion and wear

resistance similar to natural toothb) gold is relatively stable and inert in our bodies.c) Gold does not corrode & is highly polishabled) Strong even in thin section, can be burnished

for close adaptatione) Clinical longevity

GOLD INLAY

• DISADVANTAGESa) Costly(not in long run)b) Not aesthetic

Gold inlay

Gold inlay

• indicationsa) Failed amalgam restorationb) Large restorationc) Diastema closured) Rehabilitation casese) With removable prosthesis

Gold inlay

• Contra indicationsa) High cariesb) Young patientc) Esthetic concern of patientd) Small restorations

PORCELAIN INLAY

• Aesthetically excellent• More cutting for strength and translucency • Can damage opposing teeth if not properly

glazed

COMPOSITE INLAY

• Lab composite is more polymerized and has more filler content

• More strength• No polymerization shrinkage• Aesthetically excellent.

CONTRAINDICATIONS

• Cracked teeth (onlay)• Wide isthmus/deep pulpal (onlay)

Techniques

• Two techniques• Direct technique(difficult and tiring for both

the patient and the operator)• Indirect technique (easier for both and gives

better result)

DIRECT TECHNIQUE

• Where inlay wax is inserted into the prepared cavity, carved, contacts made and taken out of the cavity.

• the lab procedure than follow

Direct technique

INDIRECT TECHNIQUE

• Where an impression of the prepared cavity is taken and all other procedures are followed on the model in the lab.

Indirect technique

Steps

steps

steps

steps

steps

steps

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CEMENT LUTE

• Cement lute is the weakest part of inlay restoration

• Zinc phosphate cement and glass ionomer cements have been used for luting

• Presently non dissolving resin based luting agents are used but again the shrinkage

Controversies

• Inlays crack teeth ( careful selection)• Inlays are expensive ( are they?)• Inlays are not esthetic (careful cutting plus

tooth colored inlays)• Must place bevel at occlusal and proximal

PREPARATION

• Outline form• Resistance form• Retention form• Remove any undercuts• Finish the walls

Outline form

• A straight cut tapering fissure bur is used• Caries is removed from all around• Any existing restoration should be removed• Occlusally divergent walls (upto10 degrees)• Sharp internal angles

Outline form

• Occlusal dovetail• Butt joint at occlusal• The proximal flare must take the margin into

the respective embrasures clearing the adjacent teeth

Resistance form

• Minimum depth is 2mm all around• Proximal box should be at least 1-1.5mm

deeper• Flat pulpal floor

Resistance form

• If cusps are weak go for onlay preparation• Onlay-an inlay that covers the cusp of the tooth• Cuspal reduction-parallel to the slope• Reduction should not be less than 0.5mm

depending on the material, occlusion, working or non working cusp

• All the cusps should be out of occlusion in all excursions

Retention form

• Retention is based on nearly parallel walls• Up to 10 degree occlusal divergence is allowed

for ease of impression taking and placement of the final restoration

• There should be no undercut in the final preparation

Finish the walls

• A 60 degree gingival bevel is given by using a gingival margin trimmer

• It allows proper seal of the restoration in this area

• Paint the final outline to provide a more pleasing outline of the final restoration

I THANK YOU ALL

• All of the following are advantages of gold inlay except

a) The co efficient of thermal expansion and wear resistance is similar to natural tooth

b) Its relatively stable and inert in our bodies.c) Gold does not corrode d) A single visit procedure for the patient.