By Dr.Swathi Pai on Monday, May 5, 2008 with 0 comments

A. Indications: A porcelain restoration fracture which is relatively small and if a porcelain fused to metal restoration, has not compromised the metal-ceramic bond. Small areas of metal can be opaqued as long as sufficient porcelain remains to achieve ceramic bonding. Occlusion should, ideally, not require group function contacts where repairs are made.

B. Techniques:

1. Pre-mark occlusion and isolate area.

2. Prepare a 2 mm bevel beyond fracture wherever possible with fine grit preparation diamond and water spray.

3. Air abrade prepared porcelain and metal with 50 micron alumina.Use caution to cover adjacent porcelain restorations with rubber dam or boxing wax prior to air abrading area.

4. Apply 5-9% hydrofluoric acid (low continuous aspiration and meticulous isolation is required) for 4 minutes or 1.23% Acidulated phosphate fluoride gel for 10 minutes to prepared porcelain surfaces and any exposed metal. Rinse thoroughly with water spray.

5. Apply silane liquid to etched porcelain for 1-2 minutes. Let evaporate and gently air dry at 2 minutes.

6. Apply low viscosity dentin bond agent and opaquing agents to silanated porcelain and metal (if applicable). Light cure for 20 seconds.

7. Build-up using a hybrid composite resin of appropriate shade. Use enamel, dentin and incisal shades to simulate build-up of porcelain. Light cure in 40 sec. increments.

8. Do not begin finishing procedures for 15 min,After composite build-up is cured. (This allows for more complete setting of the silane bond - a chemical cure reaction).

Category: Prosthodontics Notes



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