My new favorite piece of equipment

May 1, 2008
I'll be honest and admit I used to make fun of computerized injection systems.

For more on this topic, go to and search using the following key words: STA device, carpule, Profound, mandible, maxillary teeth, Dr. Stanley Malamed.

I'll be honest and admit I used to make fun of computerized injection systems. Why would I ever want to pay more than $1,000 for a machine to give slow injections when I already had a brain and a thumb that could do the same thing?

For some reason, I stopped and looked at the Single Tooth Anesthesia (STA) device at a dental show, and I was surprised by what I saw. I ended up purchasing the unit for two reasons. First, though, let me offer a little background on my injection technique.

I use Profound from Steven's Pharmacy ( as a topical prior to all injections. This includes the molar furcation injections for which the STA was made. Profound works well because it is a combination of prilocaine, lidocaine, and tetracaine while most topicals are just benzocaine. In my estimation, there simply isn't a stronger topical available today.

The STA device has made it easier than ever to anesthetize individual mandibular molars. We were taught the inferior alveolar block in dental school, and I think it was certainly the toughest injection to learn. A clinician who has practiced any length of time has most likely come to the conclusion that the success rates of maxillary and mandibular anesthesia are quite different.

With thinner bone over the apices of the maxillary teeth and easier access to maxillary nerve blocks, success rates usually approach 95 percent to 98 percent — even for younger practitioners.

Unfortunately, the same thing cannot be said of the mandible. In addition to being an unpleasant injection, the success rate for IA blocks in the mandible hovers around 80 percent. According to Dr. Stanley Malamed, because of the density of the bone in the mandible, the anesthetic solution needs to be placed to within 1 mm of the target nerve. The day I learned about the 1 mm rule was the day I started looking for mandibular block alternatives.

Due to anatomical variation of the position of the mandibular foramen and the depth of soft-tissue penetration necessary to get there, this injection is missed more than any other. It has a positive aspiration rate of 10 percent to 15 percent — the highest of all the intraoral injection techniques. Patients are also left with lingual and lower lip anesthesia, which they tend not to enjoy.

For doing a quadrant of mandibular dentistry, such as the lower left, the IA block still makes a lot of sense. I once heard Dr. Malamed comment that a single carpule is rarely enough anesthesia for a lower block on an average-sized adult.

In fact, the STA has made lower blocks much easier to give; however, to use the IA block for single lower molar or two adjacent teeth strikes me as overkill. At the lab, most of the cases we see are still one or two adjacent crowns. I have stopped giving lower blocks for these types of cases.

I use the STA to administer a furcation injection, but it also can be used to give more traditional PDL injections. Because of a digital pressure sensor in the STA unit, it gives audio and visual feedback regarding whether or not the needle is in the PDL space. As with any effective PDL injection, you can set the syringe down, pick up the handpiece, and start prepping immediately.

So why did I decide to buy the STA device that day at the show?

Well, I always hated having to give a carpule on a lower block and then remove the syringe, load another carpule, and reinject. I have long dreamed about a double-sized carpule. When I saw that the STA allows the user to load a second carpule without removing the needle, I was sold.

What I didn't realize was how stress-free it makes injections, especially when I have to give multiple maxillary infiltrations. Of course, the fact that the device works with the Rapid Anesthesia technique on our newest DVD, which deals with injecting into the furcation of a lower molar to achieve single-tooth anesthesia, made this product a "no-brainer" purchase for me.

For more information on the product and clinical techniques, go to

Dr. Michael DiTolla is the Director of Clinical Research and Education at Glidewell Laboratories in Newport Beach, Calif. He lectures nationwide on both restorative and cosmetic dentistry. Dr. DiTolla has several free clinical programs available online or on DVD at For more information on this article or his seminars, please contact him at

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