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Tuesday, 31 May 2011

Free e-learning resources on glass ionomers

Vivalearning.com is a popular e-learning resource featuring lots of webinars on various dental topics. All webinars are free and CE credited! All webinars premier as live presentations and then are accessible on demand.

The Wonderful World of Glass Ionomer in Clinical Dentistry
Presentedby Dr Jeff Brucia

LIVE ON (click here to register and reserve seat)
Thursday June 6, 2011 8:00 PM ET / 5:00 PM PT
Friday June 7, 2011 0:00 AM UTC (former GMT)
CE Credits: 1

From Vivalearning.com: "A comprehensive discussion of the ever-changing world of Glass Ionomers will address the following questions. Do they still cause sensitivity? Are they any more aesthetic? Are they strong enough? How and where should they be used? Do they adhere to tooth structure? This presentation is a must for any practitioner that is considering an operative procedure in a less than ideal clinical situation."


Modern Glass Ionomers Used as Liners in the Composite Resin Sandwich Technique
Presented by Greg Gillespie DDS, Lou Graham DDS and Mark A. Latta DMD, MS
CE Credits: 1
On Demand (click here to register and access class)

This presentation was released on January 7, 2011. It is now in the form of a downloadable PDF file. The authors give a short history of glass ionomers, explain the concept of the "sandwich" technique and provide several cases to illustrate this clinical procedure.

Sunday, 22 May 2011

How to measure the depth of cure of composites according to ISO 4049?

The ISO4049 standard explains in detail how the depth of cure is measured and what is minimum depth that composites must have in order to comply with this standard. This simple procedure does not require sophisticated equipment and may be done in every dental office. It allows testing and comparison of materials and light curing units. Even if there is a radiometer to check the light intensity, it is recommended to measure the actual thickness of the composite cured by a a particular light curing unit.

Here is what we need:
  1. composite
  2. light curing unit
  3. cylindrical moulds (6 mm thick and 4-5 mm in diameter), originally it should be stainless steel, but plastic straws cut into moulds of this size may be used as well
  4. glass slab
  5. Mylar strips
  6. plastic filling instrument
  7. spatula or scalpel
And here is the step-by-step procedure:

1. Place the mould on the glass slab and fill it with composite.








2.  Place the Mylar strip on top of the composite.








3. Light-cure the composite according the manufacturer's instructions (i.e. 40 s using a conventional or 20 s using a high-power halogen or LED light).






4. Discard the Mylar strip and remove the cured material from the mould.








5. Peel off the uncured material from the bottom side of the sample using the spatula or scalpel.







6. Measure the remaining thickness of the sample and divide this number by two. The ISO 4049 standard requires that the result should be at least 1.5 mm for non-opaque shades and 0.5 mm for opaque shades.