By Michael Miller, DDS
Does the use of gauze saturated in alcohol to wipe excess composite from instruments have any effect on the strength of the composite?
Although many clinicians have used alcohol-moistened 2x2 gauze to wipe their composite placement and contouring instruments over the years without any apparently negative sequelae, it is not a good idea. Depending on how much alcohol is used, it can interfere with the adhesion of one increment of composite to another. Don’t forget - alcohol is used as a solvent for many adhesives and must be evaporated before any composite is placed. A better wetting agent is pure, unfilled resin such as Heliobond from Ivoclar Vivadent. However, even with a chemically-compatible resin such as Heliobond, you should only use a minimal amount to avoid thinning out the composite and, therefore, weakening it.
Does air abrading a tooth with 50-micron aluminum oxide prior to etching and bonding enhance bond strengths? If so, by how much?
There is no advantage to air abrading enamel and dentin prior to etching - it does not enhance bond strength. We do not recommend air abrasion for this purpose.
I would like to hear feedback regarding what cements (and bonding agents) you recommend for cementation. Some of my peers are using dual-cured and some are using light-cured-only. Whatever you recommend, please let me know your bonding agent of choice as well.
For metal-free restorations, light-cured-only resin cements appear to be more than acceptable, assuming you are using a reasonably powerful light (over 500 mW/cm2). By using a light-cured-only cement, your choice of adhesive is much easier - virtually any light-cured adhesive with a thin film thickness can be used. Just be sure to keep the adhesive from pooling in any line or point angles prior to curing. While precuring the adhesive should seal the dentin more thoroughly, it can be risky if it does pool, which would prevent you from fully seating your restoration. The best method to keep an adhesive from pooling is to air-thin with a gentle air stream. You can dispense with precuring and cure the adhesive simultaneously with the cement, but you may give up some of the dentin-sealing properties of the adhesive.
I just read the FirstLook report in a recent issue of REALITY NOW about the new product called the “Prepometer.” Have you completed your evaluation yet? If so, how accurate is it? My other question would obviously be how much remaining dentin is enough? We would assume the more the better, but can it be quantified?
As our report stated, the Prepometer is supposed to tell you how close you are to the pulp when you are preparing a tooth for a full crown. It presumably does this function by measuring the electrical conductance of the dentin. While the concept is sound, the device itself proved tricky to use and its accuracy was difficult to confirm. Regarding how much dentin is enough, the information accompanying this device suggests a minimum thickness of dentin of 0.7 mm, but we have not yet confirmed the credibility of the source.
I have been told that Tooth Slooth from a company called Professional Results should be an alternative to our Fracfinder. Do you know this product? Can you help me with information on the producer/distributor? We are very eager to learn more about this product.
We evaluated this product many years ago. It is merely a plastic instrument that has an end with one side flat and the other side pointed, except the actual tip of the point is truncated and concave. This concavity is supposed to fit on the cusp tip, where biting pressure can then be localized. If the tooth has a fracture, this is designed to isolate the part of the tooth that is compromised. It is very similar to FracFinder. You can reach the company online at toothslooth.com. By the way, according to the American Heritage College Dictionary, there is no such word as “slooth.” The correct spelling is “sleuth.”
Do you have any experience with the Opticure LED light? Designs for Vision claims it is the only curing light that cures all materials. I still haven’t invested in an LED light because of its inability to cure all materials.
Designs for Vision has not participated in our evaluation program for several years because its president was upset that we did not rate its products number 1 across-the-board. With this in mind, we continue to urge restraint, especially since this is their first foray into the curing light market. The only LEDs we have tested that have been able to cure all of our test materials are the Ultra-Lume 5 from Ultradent and the brand new G-Light from GC.
Do you see a problem with using LuxaCore as the cement and the core buildup for an esthetic post like Snowpost or DT Post? The manufacturers (Zenith and Bisco) indicate this procedure is acceptable. If this is not an acceptable treatment option, can you give some input? Also, what is a good matrix for placing the core buildup for a tooth that has been broken to gumline?
LuxaCore should function just fine as both the cement for the post as well as the build-up material. Two different core forms are described in our 2005 Annual Edition. Both are acceptable, but neither is outstanding. Depending on the situation, freehand application not using any core form may be the best option, assuming you have good tissue management and the margins of the tooth are fully exposed, typically using cord. For posterior teeth, you also may want to try an old-fashioned copper band.
Dr. Michael Miller is the publisher of REALITY and REALITY Now, the information source for esthetic dentistry. He is an international lecturer and a fellow of the American Academy of Cosmetic Dentistry, as well as a founding member. He maintains a private practice in Houston. For more information on REALITY and to receive a complimentary issue of his monthly update, REALITY Now, call (800) 544-4999 or visit www.realityesthetics.com.
