Michael Miller, DDS
We are experiencing a higher-than-acceptable amount of errors when transferring casts between articulators. We facebow mount our casts on Denars that are field-calibrated once a week. Interocclusal stops are verified with shimstock (12 micron). We send our mounted casts to our lab, which verifies the mounting on its field-calibrated Denar. The lab is to remount if two thicknesses of shimstock pull through the interocclusal stops, and it is currently remounting 80 percent of our cases. Is there another articulator system that more accurately transfers casts between calibrated articulators? If so, please provide a reference. All articulator companies claim accurate transferability of casts. Is there any literature comparing the accuracy of various two-articulator systems?
A: Apparently you're not the only one to discover that Denar articulators have a problem "talking" to one another. In researching your questions, REALITY editorial team member Dr. Nate Birnbaum found that a number of notable clinicians and laboratories have found problems with the transferability of casts between Denar articulators, as well as many other articulator systems. The choices of these individuals for improved results are the Artex (Jensen Industries) and the SAM (Great Lakes Orthodontics) articulator systems.
The consensus of the clinicians and technicians is that the Artex articulator from Jensen Industries affords the greatest accuracy in the transfer of casts between articulators. Casts in most other articulator systems are retained via a screw mechanism, whereas the Artex articulator system uses magnets.
Studies demonstrating the accuracy of cast transferability in the Artex articulator system, compared to other systems, have been carried out by Jimmy Eubanks, who performed a five-year study on the subject through Tufts University, and by Charlie Cajdric, an authority on the subject.
More information on the Artex articulator can be obtained by contacting Marcello Allegra of Jensen Industries at (800) 243-2000.
Q: I find the idea of sealing composite restorations with flowable composite very interesting. What is your opinion? If you agree with it, would you please describe the protocol to use?
A: We definitely recommend the use of flowables under packable composites, especially on the gingival wall of a proximal box in a Class II restoration. When using a flowable, complete your normal adhesive procedures and inject the flowable as the first increment, light-cure, and then continue with the restoration as usual. We have numerous clinical photos illustrating how to use flowables for Class II situations in the 2001 edition of REALITY.
Q: I have a patient who is a late 30s female who has been bleaching her teeth for four weeks, three to four hours each day. She started with Opalescence 15 percent. After one week, she noticed "white spots" appearing and had some problems with sensitivity. I switched her to 10 percent and told her that the mottled look would likely fade away. Now, three weeks later, she is beginning to panic. The mottled appearance remains, and it appears that the rest of the enamel is not lightening like the hypoplastic areas (if that's what they are). She thinks she'll look this way forever. (It's actually not all that bad, in my opinion.) My inclination is to have her hang in there and continue the process for several more weeks. Have you seen similar cases? Any suggestions?
A: Enamel surface abrasion, covered in the 2001 edition of REALITY, is your best bet. Opalustre from Ultradent is our choice for this procedure. We suggest stopping the bleaching, performing the enamel surface abrasion, and letting things calm down. The patient could resume bleaching, assuming the enamel surface abrasion is successful in removing most - if not all - of the white spots.
Dr. 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, Texas. 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. The opinions expressed in the column are not necessarily the opinions of the Dental Economics staff.