Research: New therapy for hypersensitivity promises three times longer relief

by Nelson Gendusa, DDS
Director - Research

Depending on your particular practice, somewhere between 10 and 40% of the patients who present at recall suffer non-pathological hypersensitivity.^{1, 2} (And if your practice is heavily weighted with post-surgical perio patients, that range may be more like 50%-100%!) ^{3, 4}

Even highly sensitive patients may not tell you they have a problem. Some have lived with sensitivity so long, they’ve learned to cope. They avoid ice cream - fill water glasses with warm water - avoid breathing through their mouth on a cold morning.

So unless you or your hygienists ask questions and do some testing, you may never learn of the problem.

That’s a shame, because dentin hypersensitivity has never been so treatable. In fact, if you’re still using the same desensitizers you were using just 4 years ago, you may not be giving your patients the kind of relief they deserve.

For example, a recent clinical study at the University of Alabama tracked the long-term effectiveness of Touch&Bond™ as a cervical desensitizer. 204 sensitive dentin surfaces were treated and their sensitivity was monitored for two years.⁵

Baseline effectiveness - 100%
1-day effectiveness - 100%
3-month effectiveness - 96.6%
6 Month effectiveness - 92.2%
1 year effectiveness - 79.4%
2-year effectiveness - 76.0%

Graph #1 (below) compares this performance with a similar study using a rub-on desensitizer.⁶ In terms of long-term success, Touch&Bond leaves our rub-on desensitizer (as well as virtually every other desensitizing agent) sitting in the dust.

Unfortunately, there’s a limitation to Touch&Bond as a desensitizer. It creates a very thin, somewhat resilient film. That’s fine for bonding applications where the adhesive will be covered with composite - but when it’s exposed to the oral environment this film is susceptible to tooth-brush abrasion.

That’s probably why roughly 25% of the patients saw some recurrence after 2 years.*

So THAT’S why Brush&Bond™ was developed

As I’ve said many times in Parkell Today as well as in our Adhesion Newslettter, Brush&Bond™ is a kissing cousin to Touch&Bond. Both are 4-META-based, no-etch systems. And they both penetrate the dentin and seal open tubules using the same hybridizing mechanism. From a resin-bonding standpoint, I really can’t make a compelling argument for one product over the other.

But Brush&Bond is a better choice for cervical desensitization.

It’s easier to use. Those of you who use it for bonding know it takes just slightly over half a minute to apply and cure. You polymerize it with any kind of curing light. But its most important feature for desensitizing is something I’ve scarcely mentioned. Brush&Bond creates a thicker, more robust polymer film ... one that withstands abrasion much better than Touch&Bond or Pain-Free. This means that its desensitizing effect lasts significantly longer.

“How MUCH longer?” you ask. In joint research at the Universities of Alabama and Kagoshima, the Brush&Bond polymer film was found to be 3-4 times as wear-resistant as Touch&Bond’s.⁷

Brush&Bond’s polymer layer is not only 3-4 times as wear- resistant - it’s also three times as thick as Touch&Bond’s (9 microns vs 3 microns.)

Other work at Japan’s Tsurumi Dental School showed that Brush&Bond’s film was harder than other materials used to protect exposed dentin. Based on their results, they speculated that Brush&Bond alone (that is, without an overlying composite) might protect dentin exposed by instrumentation as effectively as a restoration!⁸

A SHOCKING SECRET about Brush&Bond

Till now, we’ve marketed Brush&Bond primarily as a composite bonding agent. And it’s proven to be a terrific one. Two independent newsletters recently gave it their highest ratings among all the bonding agents evaluated.

But the fact is, Brush&Bond didn’t start out as a bonding agent. It grew out of desensitization research at the Sun Medical Research Lab in Japan. And it’s registered with the Japanese Health Ministry not as a bonding agent - but as a dentin desensitizer.

You might say that Touch&Bond is a bonding agent that turned out to be an effective desensitizer. And Brush&Bond is a desensitizer that turned out to be a terrific bonding agent.

Why Brush&Bond is better for desensitization than a total-etch agent

For one thing Brush&Bond creates a tougher protective polymer than many total-etch systems. And its desensitizing procedure is much faster. Just seconds instead of minutes.

A total-etch approach first blasts tubules wide open with acid and then subsequently seals them. If anything goes wrong with the “sealing” part of the equation, total-etch has the potential to make sensitivity even worse than it was before treatment. With Brush&Bond, there’s no etching. It seals those offending open tubules without any possibility of opening new ones.

Traditional phosphoric acid is highly acidic. When you put it on sensitive dentin, it can cause a massive fluid shift and trigger extensive firing of those Type A neurons. In other words, the mere act of putting strong acid on sensitive dentin can trigger a dramatic “ouch” response.

Brush&Bond is much less acidic (pH - 2.5). Though some hypersensitive patients will feel it, it’s less objectionable than a traditional acid-etch procedure.

That means you can treat most hypersensitive dentin without using anesthesia. This is important for several reasons.

For one thing, you can use your air syringe to immediately confirm that the treatment has worked - or even ask the patient to swish with cold water! If the patient was suffering major hypersensitivity, I can guarantee you’ll be a hero. (This can be an opportunity for some serious patient bonding.)

Another reason it’s better not to anesthetize is that desensitization can provide a differential diagnosis. Open tubules is the most common cause of sensitivity, but it’s certainly not the only cause. Believe it or not, leaking occlusal margins can cause root sensitivity. So can cracks. Or poorly-cured composite restorations. Or pulpal inflammation.

If your hygienists routinely screen and treat hypersensitivity, be sure they understand the importance of alerting you when the treatment isn’t effective, so you can take a closer look at the films and ask some questions about occlusal habits

1 Rosenthal M, Historic review of the management of tooth hypersensitivity, Dent Clin N Am. 34:403-427, 90
2 Banoczy J. Dentin hypersensitivity and its significance in dental practice. Fogorv Sz. 95:6, p223-8, Dec 02
3 von Roil B, et al. A systematic review of the prevalence of root sensitivity following periodontal therapy. J Clin Periodotol. 29:Suppl 3, p173-7, 2002
4 Gillam DG, et al. Prevalence of dentine hypersensitivity in referred periodontal patients. Jour Dent Res, 74:Spec, Abstr #383, p448, Jn 95
5 Suzuki, et al. Clinical evaluation of Touch&Bond Adhesive System as a desensitizer for dentin hypersensitivity. Research Monograph - Oct 03 (Available on request)
6 Suzuki S, Long-term clinical evaluation of a desensitizers against cervical hypersensitivity. J. Dent Hlth of Japan, 49:640, 1999
7 5 Suzuki S, et al. In vitro wear evaluation of desensitizers for dentin hypersensitivity. IADR - San Antonio, Abstr #0953, 2003
8 6 Akimoto A, et al. Mechanical properties of new dentin coating material. Nip Adhes Dent, 21:1, p17-23, 2003

* What you DON’T see in the graph is that even when sensitivity recurred, it was much less severe, and could be easily treated with another application of Touch&Bond.