INLAYS AND ONLAYS

FARYAL HABIBULLAHROLL NUMBER 76

• An inlay is defined as a restoration which has been constructed out of the mouth from gold, porcelain or other metal and then cemented into the prepared cavity of the tooth.

The onlay is essentially an inlay that covers one or more cusp and adjoining occlusal surface of the tooth.

ONLAY

Cast metals

Tooth coloured

INDIRECT RESTORATION

High Gold alloys

Low Gold alloys

Palladium Silver alloys

Base Metal Alloys

Porcelain

composite

• Large restorations

• Endodontic ally treated teeth

• Teeth at risk for fracture

• Dental Rehabilitation with cast Metal Alloys

• Diastema closure and occlusal plane correction

• Removable prosthodontic abutment

INDICATIONS

• High caries rate

• Young patients

• Esthetics

• Small restorations

CONTRAINDICATIONS

• Strength

• Biocompatibilty

• Low wear

• Control of contours

ADVANTAGES

• Number of appointment

• Higher chair time

• Temporary Restorationa

• Cost

• Technique sensitive

• Splitting forces

Disadvantages

METHODS

DIRECT METHOD INDIRECT METHOD

BASIC PRINCIPLES OF CASTRESTORATIONS

TOOTH PREPARATION FOR INLAYS

OCCLUSAL PREPARATION

6° flare

• Initial entry is made in the central fossa with a tapered fissure bur•Ideallyocclusal depth 1mm in dentine or 2.5mm at triangular ridges.•Bur should be vertical its taper provide 3 to 5-degree divergence

1-Tapered fissure bur is used to create mesial and or distal proximal boxes

2-thin layer of enamel is left to protect the adjacent tooth

3-Gingival floor of box should have an axial depth of 1.0 to 1.5mm

4.The axial wall of the box should follow the faciolinual contour of external surface of tooth

PROXIMAL BOXES

REFINEMENT1-All preparation floor and should be smooth2- all walls should be divergent except axial3-axial wall should be convergent occlusally

PROXIMAL BOXESProximal bevel on facial and lingual walls of the box With garnet disk OR THIN flame shape bur and blend with Gingival and occlusal bevels.

The walls of the prep should diverge from the gingival floorin the occlusal direction.

BEVELS OF HORIZONTAL CAVOSURFACE ANGLES

0.5 MM WIDE Bevels wide At occlusal proximal and gingival angles

DECISION TO ONLAY???

ONLAY TOOTH PREPARATION

• Occlusal preparation• Proximal boxes• Cuspal reduction• Shoulder preparation• Noncentric cusp• Gingival bevel• Shoulder bevel• Proximal bevels• Retention grooves

Cuspal reduction