Laser Curing - The Weak Link

Thomas K. Hedge D.D.S., F.A.C.E.
Pending Publication

I have always felt that the economic argument for overhead savings by using laser curing was fundamentally flawed. I was never sure of why until today, when I was looking at our appointment book displayed on one of our computer monitors. The weak link is in our scheduling time increments. Most doctors schedule in ten or fifteen minute time intervals.

The economic argument for laser curing states that, dentists spend 30 eight hour days per year curing composites. This has an estimated value of $48,000 based on a $200 per hour gross. The figure of thirty eight hour days is based upon 240 eight hour work days per year, curing 10 Class II restorations per day using six minutes of total cure time for liner, adhesive, layering, external cure in several directions, post cure, and surface sealant resin cure. The claim is that these numbers can be reduced to five days and $8,000 using lasers and PAC lights.

This amounts to $40,000 dollars in overhead time reduction. This should justify buying a laser for every room and having money left over. Does something sound wrong to you here?

First of all, how many people spend six minutes curing a single posterior Class II resin? I don’t. I spend, maybe, a little over a minute. I use Onestep from Bisco as my bonding agent (10 seconds), a layer of Tetric Flow (40 seconds for two millimeters), and Z-100 Restorative (40 seconds). Since the Tetric Flow layer is only a half millimeter thick and is later cured by the Z-100 cure, I usually only cure this layer for ten seconds. This is a bout a minute in cure time.

How long will these same steps take using a laser or PAC light? Two seconds each for the bond and flowable layer and five seconds for the Z-100 for a total of about ten seconds. This saves fifty seconds per composite.

Lets look in our appointment book and schedule a patient for a single Class II composite. Will we schedule 40 minutes is we use a conventional light and thirty-nine minutes if we use a laser or PAC? Clearly our appointment book time interval will not let us. What if we did a whole quadrant at once? This would save fifty seconds times four or just over three minutes. We still cannot even mathematically round down to the next ten minute interval. How can we be saving time this way?

Many practices utilize assistants and expanded duty personnel that perform the light curing while the doctor produces elsewhere. The assistant time is at most one tenth the cost of doctor time. This makes the purchase of a PAC or laser almost unjustifiable.