Onlay

Question 1

How could discoloured anterior teeth be managed?

Answer 1

• Acid pumice abrasion
• Non-vital bleaching
• Vital bleaching
• Veneers
• Crowns
• Composite

Question 2

What is an inlay?

Answer 2

Intra-coronal restoration made partly or completely outside the mouth.

Question 3

What is an onlay?

Answer 3

Intra-coronal restoration made partly or completely outside the mouth with partial or complete cuspal coverage.

Question 4

What can inlays and onlays be made from?

Answer 4

• Gold alloys (60% gold, 22% silver, 13% copper, 3.5% palladium and zinc and iron) (best for wear and won’t fracture, careful though as if opposing tooth is made from porcelain or ceramic could wear it down)
• tooth coloured material :
  1. porcelain fused to metal (PFM)
  2. all ceramic
  3. Emax (lithium disilicate glass ceramic) (v.strong)
  4. zirconium oxide

Question 5

What are the indications for gold inlays/onlays?

Answer 5

• large restorations
• endodontically treated teeth (onlays only)
• teeth at risk of fracture
• wide open contacts and occlusal plane correction
• subgingival lesions
• prosthodontic abutments

Question 6

Contraindications for gold inlays/onlays?

Answer 6

• young dentition with large pulp chambers
• aesthetics
• poor OH
• small restoration

Question 7

Advantages of gold inlays/onlays?

Answer 7

• strength and low wear
• biocompatibility
• control of contours and contacts

Question 8

Disadvantages of gold inlays/onlays?

Answer 8

-Extensive tooth prep
-cemented restoration, discrepancy and micro leakage
-can have abrasive/splitting force on natural teeth
-appointments and cost
-technique sensitive
galvanic currents

Question 9

What should the tooth prep be like for gold inlays/onlays?

Answer 9

• undercut free with single path of insertion

- max height with taper of around 10 degrees

Question 10

Advantage of tooth coloured onlay to gold?

Answer 10

• aesthetics

- less flare of wall required (only 6-10 degree) and margins don’t require bevelling

Question 11

What imps do you need when doing crowns/onlay?

Answer 11

• silicone of arch you’re working on
• opposing alginate
• bite registration in ICP using hydrobite

Question 12

What materials could you use to temporise an onlay?

Answer 12

• soft light cured resins (Fermit)
• self cured acrylic resin (Protemp or Maxitemp)
• Telio (light cured) (what I used)

Question 13

What are the potential failures of inlays/onlays?

Answer 13

• fracture

- secondary caries