Laird Harrison

March 27, 2012

March 27, 2012 (Tampa, Florida) — Invisalign clear plastic orthodontic aligners cost more in materials than conventional edgewise braces, but they require fewer patient visits and a shorter duration of treatment, researchers reported here at the American Association for Dental Research 2012 Annual Meeting.

Both approaches to moving teeth are useful, first author Michael Ross, a dental student at the Baylor College of Dentistry in Dallas, Texas, told Medscape Medical News. "It's weighing the time cost against the material costs," he said.

In the Invisalign system, practitioners fit their patients with a series of plastic aligners fabricated in a laboratory that incrementally adjust the teeth in the desired direction. The system has allowed some general dentists to do what only orthodontists could do before. But few studies have measured which approach is more efficient in time or money.

To explore this question, Rossi and his colleagues evaluated the records of 150 patients with mild to moderate class I malocclusion. The 2 groups were matched for the amount of initial malocclusion and the number of rotated teeth.

The researchers measured the time taken by appointments for both types of treatment with a stopwatch.

They found that conventional braces required a median of 13.6 minutes for a routine visit, whereas Invisalign required 9.9 minutes. Emergency, initial, and final appointments were all longer than regular visits.

Conventional braces required about 2.6 more visits than Invisalign, treatment for 2.4 months longer, 1.1 more emergency visits, 9.7 minutes more in chair time, 1.2 minutes more emergency doctor time, and 86.2 minutes more in total chair time (P < .01 for all).

However, Invisalign cost $500 to $1441 more in materials and required 5.9 minutes more doctor time than conventional braces (P < .01).

Measuring profitability as fees minus the cost of materials, Invisalign was more profitable than conventional braces, the researchers found, especially for Invisalign providers who are charged $899 in lab costs, a discount that the appliance maker, Align, offers to doctors who do more cases.

For these doctors, Invisalign provided about $1000 of profit per hour of chair time with the first $2750 in fees to the patient, rising to $3250 with $6000 in fees. Doctors who are charged $1549 in lab costs by Align had a profit of about $500 with the first $2750 in fees, rising to $3000 with $6000 in fees.

Braces were less profitable overall, starting at $750 per hour of chair time with the first $2750 in fees, but reaching only $2000 with $6000 in fees.

Asked to comment, Allen Firestone, DDS, MS, professor of orthodontics at Ohio State University in Columbus, told Medscape Medical News that doctor time could vary a lot from doctor to doctor; all the records in this study were obtained from one orthodontist's office.

Dr. Firestone, who was not involved in the study, uses both treatments in his own practice. "Invisalign is a very effective way of treating a broad range of orthodontic problems," he said, "but you have to choose your patients."

He explained that Invisalign is more esthetic because the clear aligners are hard to see, are less irritating to the tissue, and allow better hygiene because they can be removed.

However, it relies more on patient compliance, and some tooth movements are more difficult, he said. "As an orthodontist, I can use braces on some teeth and Invisalign on others," he said. "You want a practitioner who is using Invisalign because it's good for the patient, not because it's good for the practitioner."

Mr. Ross and Dr. Firestone have disclosed no relevant financial relationships.

American Association for Dental Research (AADR) 2012 Annual Meeting. Abstract 408. Presented March 22, 2012.


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