There are two procedures to fabricate the inlays and onlays. One is direct and the other is indirect. In direct procedure the inlay and onlay is made directly in patient’s mouth in single visit only. They are composite inlays or onlays. In indirect procedure the inlays and onlays are made in the laboratory after taking the impression. Then the laboratory prepares them on the basis of impressions taken by the dentist. After the preparation on of Inlays and Onlays by the laboratory, these are checked by the dentist and fitted in the patient’s mouth. Any minor adjustments needed to make them fit in patient mouth are made by the dentist with instruments at his disposal. Inlays and Onlays is fairly simple procedure and is routinely carried out by the dentists. The fixation of Inlays and Onlays does not involve any surgical procedures and is mostly pain free.
Direct Inlay and Onlay (Composite)
Outline of clinical procedures:
1. Select shade.
2. Isolate with rubber dam
3. Pre wedge for proximal lesions.
4. Cavity preparation.
(a) All margins in enamel if possible.
(b) Break proximal contact.
(c) Tapered preparation (divergent wall 8-12 degree)
(d) Rounded internal line angles.
(e) Eliminate undercuts.
(f) Ends of enamel rods exposed for etching.
1. Matrix and wedge.
2. Apply separating medium.
3. Place composite in incremental fashion curing thoroughly.
4. Remove restoration from tooth.
5. clean restoration and provide additional curing
6. Check contour, fit and contact and adjust/add resin as necessary.
7. clean internal surface of restoration.(sandblast , etching gel)
8. apply special bond(vivadent)
9. protect adjacent teeth (celluloid strips, matrix)
10. Clean and etch enamel and apply appropriate bonding resin.
11. Cement inlay.
(i) Always use dual cure cement
(ii) Apply cement to tooth and restoration.
12. Seat with gentle pressure and remove excess.
13. Seat firmly (and remove excess cement at all margins) and hold in place with instrument.
14. Apply curing light from several angles (60 seconds each angle) while maintaining pressure on restoration.
15. Allow cement to continue polymerization for 10 minutes with no curing light/ pressure.
16. Finish restoration.
Indirect Inlay and Onlay Preparation (Laboratory Procedure)
1. Isolate and select shade.
2. Apply rubber dam.
3. Pre wedge for proximal lesion.
4. Cavity preparation.
5. Take impression.
Impression should have:
1. High tensile strength.
2. Good surface detail.
3. Low deformation.
4. Able to disinfect it without distortion.
For impression addition silicones can be used.
For onlays and large inlays take impression for opposing model and bite registration.
(a) Use appropriate material.
(b) Always cement temporary with a non Eugenol luting agent such as TEMP-BOND NE(kerr)
The provisional restoration should:
(a) Stabilize the existing occlusal relationship
(b) Protect the prepared teeth from any anxious stimuli.
At second appointment:
1. Inlay or onlay is prepared in laboratory from the impression.
2. Isolate with rubber dam.
3. Remove all temporary material.
4. Cement the inlay or onlay to the tooth.
5. Polish the restoration.
6. It is contoured and check for fit and contact.
Inlays and onlays require brushing and flossing. The patient should visit dentist regularly.
Inlays and onlays can become loose if cement washes out or combines with saliva while it is being applied. Inlays and onlays made of composite resin or porcelain can crack.