Aesthetics in Dentistry

FAQ’s

1.How do I match a single upper central incisor tooth?

  • This is not easy.
  • Expect a try-in.
  • Custom shade.
  • May be able to justify adjacent restoration especially if it is an existing crown.
  • Bleaching of adjacent teeth may be simpler if shade is too bright.

2.Can I mix veneers and crowns?

  • Best result will always be easier to achieve with the same restorations.
  • Veneers and crowns may be mixed if underlying tooth structure is normal and not discoloured.
  • Compare biological and financial cost with long term success

3.Does bleaching work?

  • Yes, if a standard 10-16% carbamide peroxide gel is used for at least 2 hours per day for 2-4 weeks.
  • A shade change of 1 or 2 on the Vita shade guide should be expected.
  • Technically it is still illegal but Protection Societies will support its use on clinical grounds.

4.Do all porcelain crowns provide the best aesthetics?

  • Probably yes but many other factors to consider.
  • Most important factor is the quality of the technician
  • A heavier preparation is required which may lead to greater sensitivity and possibly endodontic treatment.
  • Sufficient tooth preparation will give your technician enough space to mask a metal alloy coping or a bright white ceramic core. Recent developments with tooth coloured zirconia copings show promise.

5.When would crown lengthening surgery help with providing an

aesthetic result?

  • The main use is to increase the clinical crown height to allow retentive tooth preparations. This is most useful when managing localised or generalised tooth wear.
  • Irregularities in the gingival margin will also be corrected by crown lengthening surgery.
  • Chronic inflammation around existing crowns may also be best treated by crown lengthening surgery, particularly if the margins are deeply sub-gingival invading the biologic width.

6.Is surface staining of porcelain effective?

  • Yes, but the result will not last with time as the surface layers wear away. Some ceramic systems rely solely on surface staining.
  • Surface staining will be effective if the try in porcelain is a higher value and lower chroma than required.

7.Should I buy a shade taking machine?

  • These machines are useful in selecting a basic shade as a colour corrected light source is used.
  • Working with the technician is still vital as many other factors need to be prescribed for good shade and shape matching.
  • The value is the most important component of colour to get right with matching.

8.Is a diagnostic wax-up required for all cases?

  • No, but it will be very useful for the larger or more difficult aesthetic cases.
  • It provides a guide and comparison for the patient and clinician.
  • It can be used as a former for a matrix used to help with tooth preparations and in the making of temporary crowns or bridges.
  • It is analogous to a prosthetic wax-try in or an orthodontic Kesling set-up.
  • Other guides are the use of photographs, direct composite additions and the use of temporary or provisional crowns and bridges.

9.Will implants provide a better appearance than a resin-bonded or

conventional bridge?

  • In an ideal case an implant may provide the best appearance but such cases are rare.
  • Immediate placement into a tooth socket between adjacent teeth would give the best chance of a good aesthetic outcome. The implant head should be no more than 5mm from the contact point to preserve the interdental papilla.
  • Adjacent implants do not preserve the interdental papilla.
  • Recession occurs around implants with greater aesthetic problems than around teeth.

10.How long will my aesthetic make over last?

  • Median survival times for restorations would indicate:

Composite veneer-7 years

Porcelain veneer-10 years

Crown PFM-20 years

Crown ceramic-N/A 5 year results only

Implant-N/A 15 year results for partial

25 year results for edentulous

  • Clinical trials do not equate to clinical practice.
  • 40% of sub-gingival crown margins will be supra gingival in 1 year.Valdeharg & Birkland 1976

11.What material would work best for my temporary crowns or bridges?

  • Temporaries made directly at the chair side which may be expected to last weeks would be made of acrylic or composite.
  • Temporaries expected to last months are best made indirectly in the laboratory.
  • Provisional or long-term temporaries which can last some years are definitely best made in the laboratory. A non-precious metal framework with composite (e.g. Belleglass) will provide a durable aesthetic result.
  • Composite is brittle and margins are easily damaged if used repeatedly. This will be less of a problem with an acrylic.Trim (butylmethacrylate) allows some flexibility and may last better as a chair side temporary bridge.
  • Matrices from diagnostic wax-ups are invaluable in making temporaries. A “shell” technique which is relined can provide a simple and aesthetic result.

Ken Hemmings

Consultant in Restorative Dentistry

November2009