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 ques-tions and do some testing, you may never learn of the problem.
That’s a shame, because dentin hyper-sensitivity has never been so treatable. In fact, if you’re still using the same desensi-tizers 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
Graph #1 compares this performance with a similar study using a rub-on desen-sitizer.6 In terms of long-term success, Touch&Bond leaves our other desen-sitizer (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 toothbrush abrasion.
That’s probably why roughly 25% of the patients saw some recurrence after 2 years.*
And THAT’S why Brush&Bond was developed... As I’ve said many times in this newslet-ter, 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 can cure it with any kind of curing light. But its most impor-tant 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
But the difference is actually greater than that. 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.)
Adhesive Newsletter #42
Some totally tubular thinking about sensitivity.From Nelson Gendusa, D.D.S. – Director of Research
Graph 1: A polymer film lasts longer. As you can see in this graph, about 70% of the sensi-tive teeth experienced long-term desensitization. Of those who report some degree of recurrence, Touch&Bond’s polymerized film lasted signifi-cantly longer before retreat-ment was necessary.
* 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.
Graph 2: Brush&Bond resists mechanical wear better. To demonstrate relative resistance to abrasion research-ers submitted coated dentin to continuous tooth brushing using a Sonocare toothbrush and Crest toothpaste, and then measured the amount of material removed.7
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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 bond-ing 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 Medi-cal 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 was 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 subsequent-ly seals them.
If anything goes wrong with the “seal-ing” 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 osmotic pressure and 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 hypersensi-tive 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 hypersensitiv-ity, 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 anesthe-tize 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
Graph 3: Brush&Bond creates a harder protective surface. After a week in water, researchers measured the nano-hardness of the coated tooth surface.8
Graph 4: Brush&Bond even occludes tu-bules better. Whether the patient will really notice a difference between 85% and 98% occlusion is debatable. (As-ymptomatic dentin often contains some open tubules.) But if you’re applying the adhesive in order to protect the pulp from irritants, the greater the seal the better.
Read What Researchers Are Writing About Brush&Bond As A Protector
And Desensitizer Of Dentin“Our data demonstrate that the newly developed dentin coating material (Brush&Bond) is useful for treatment of instrumented dentin ... “ – Naotake Akimoto, et al.
Nippon Journal of Adhesion Dentistry
“Considering the handling properties of each (desensitiz-ing) material, it was concluded that Brush&Bond is a good material for resin coating with a thin film.” – Toru Nikaido, et al
Japanese Journal of the Conservative Dentistry
“Our hygienists had positive experiences using Brush&Bond in the treatment of cervical sensitivity.” – Gary Schoenrock, DDS
can take a closer look at the films and ask some questions about occlusal habits.
Do Self-etchers really reduce sensitivity? Proof – pudding – and JADA articlesI know that Brush&Bond and Touch&Bond reduce post-op sensitivity when compared with total-etch systems. I know it as certainly as I know God made little green apples, and the Giants will not win the 2005 Superbowl.
How can I be so sure? Because real dentists tell me that. In our recent sur-vey of Brush&Bond users with at least 6-months experience, we asked them how it compared with their prior bonding agent in terms of post-op sensitivity.
If they’d previously been using a 5th generation total-etch bonding agent (Prime&Bond NT, One-Step, etc) 88% reported that Brush&Bond was “better” or even “wonderful” in preventing sensitiv-ity. In other words, almost 90% judged it better. That’s as close as you’ll ever get to unanimity among dentists.
And it’s not just when WE ask the question, either –
When CRA asked dentists to report the frequency of post-op sensitivity, 17% of total-etch users said that at least 11% of their bonded restorations were sensitive. The corresponding response from self-etch users was just 4%.
However, if an “evidence-based” dentist went looking through journals, he’d probably conclude that this desensitization claim was bogus.
Take the study performed at the Univer-sity of Minnesota and reported in last December’s JADA.9 It compared post-op sensitivity after restorations were bonded with total-etch Prime&Bond NT and self-etch Clearfil SE. They concluded there was no difference.
How can this be?
For one thing, dentists and researchers mean two different things when they talk about “post-op sensitivity”. And they use different criteria in determining when it’s severe.
But most important - Researchers don’t live in the real world.
Fact: Bonding agents don’t generally cause sensitivity. Dentists cause sensi-tivity. When used precisely as intended,
no bonding agent should produce sensitiv-ity. Not 4th generation materials. Not 5th generation materials. And certainly not 6th, 7th or 8th generation.
But, of course, there’s a catch. Some bonding agents demand a lot more care to be used “exactly as intended” than others. If you leave the dentin just a little too wet or a little too dry ... If you “rub” instead of “dab” (or conversely “dab” instead of “rub”)... or you don’t leave the material on the tooth for precisely the prescribed length of time ... some adhesives can generate serious post-op complaints.10
When dentists participate in a formal study, they have a heightened awareness of the importance of meticulous technique - AND they have all the time in the world to follow it.
As a result, formal research sometimes finds much lower levels of post-op sensitivity in the clinic than those reported by real dentists who operate under the constraints of private practice.
Give those same researchers 20 minutes to do the restoration – plus $200,000 of student loans to repay plus a dental assistant who just gave her notice that morning - and watch the level of post-op sensitivity increase.
Yes - Self-etchers reduce post-op sensitivity. But only in the real world.
Here’s what dentists told us after they’d bonded 50,000 restorations with Brush&BondAfter 6-months-to-a-1-year using Brush&Bond 80% (Okay, 79.5%) report no problems at all. None. Zero.
When we asked their overall opinion of the product, 72.5% indicated it was “Ter-rific”... 27.5% felt it was “Good.”
That adds up to 100%. In other words, not a single dentist rated it less than “Good.”
As in our earlier survey, the most common problem with Brush&Bond was the size of the Microbrush head, which some dentists reported was too large to fit into their mi-cro preparations. (Once you’ve stirred the liquid with the special Microbrush – you can apply it with anything you want.)
Only 1.7% of the respondents reported any sensitivity at all with Brush&Bond. This is the lowest number we’ve seen for any adhesive we’ve ever surveyed - and that includes Touch&Bond (which was
4.6%). In fact, I’m really beginning to question the “common knowledge” that all self-etch bonding agents are equally desensitizing. Almost 2/3rds of the dentists who’d previously used Clearfil SE judged Brush&Bond “Better” or even “Wonderful” in terms of desensitization.
There weren’t any huge surprises in the study. The most common bonding agents previously used by dentists switching to Brush&Bond were -
Touch&Bond (40%)
Clearfil SE (25%)
Prime&Bond NT (23%)
Prompt-L-Pop (20%)
As you can see, most users switched to Brush&Bond from other Self-Etch bond-ing agents. When we asked a similar ques-tion of Touch&Bond users two years ago, virtually everyone said they’d switched from a 4th or 5th generation material. This demonstrates how quickly the bonding field has changed. Self-etchers now rule the roost.
We received several excellent suggestions from the respondents. The best came from an anonymous dentist who asked why we hadn’t printed a “Technical Tips and Frequently Asked Questions” flyer. The reason is very simple. We didn’t think of it. We are now distributing a FAQs sheet with each kit. (Some of the questions ap-pear in the sidebar to the right.)
Research vs Reality “Bonds in your mouth - not in their hands”Nothing in this world gets you out of those “Oh-terrific-what-do-I-do-now?” clinical nightmares like C&B-Metabond. For two decades it has been the go-to ce-ment for repairing fractured teeth... re-cementing crowns... bonding to ab-surdly non-retentive preps or cementing short posts.
Hardly a week goes by that I don’t hear from a Metabondito who wants to share some extraordinary story.
So here’s something that may shock you.
C&B-Metabond (the mother of all adhesive cements) doesn’t show astro-nomical bond strength data. In fact, if you just looked at the in vitro BS tests, you’d never imagine what a struggle it is to remove a Metabonded crown.
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A recent well-researched article in the Journal of Dental Materials tried to explain this paradox.11 The team set out to examine bonds to post-cured composite, and wound up attempting to explain why C&B-Metabond works in such demand-ing applications in the mouth - despite its moderate performance in the lab.
For one thing, there was C&B-Meta-bond’s resilience. Unlike the other cements they tested, C&B-Metabond doesn’t fail abruptly during the tension test. Instead, it stretches. Then it stretches some more. Only when it has stretched beyond its limit does the bond fail.
In their micrographs they could actually see the difference between C&B-Meta-bond and the other resin cements.
Other cements showed brittle fracture (Fig. 2). They failed instantly. Crack! The surfaces looked like a fractured ceramic pot or broken brick. In contrast, the Metabonded surfaces were still coated with the adhesive, and that adhesive was stretched into strange stalactites or fins of material (Fig. 1).
They pointed out that C&B-Metabond has 10 times the toughness of a conventional filled resin cement, and that its resilience may counteract stress during setting. Also because of its unique slow-setting proper-ties, C&B-Metabond may flow better, creating less stress as it gels.
Two points - these are MY points - not necessarily the researchers’: (1) C&B-Metabond is utterly different from all other cements. (2) And once again, bond strength numbers have no relationship to clinical performance.
Bonds in your mouth, etc, etc - part 2Another study compared the force neces-sary to remove high gold crowns from preparations of increasing taper.12 The researchers noticed an astonishing thing about C&B-Metabond. When the taper was 12°, C&B-Metabond was actually more retentive than when it was 6°. In other words, the worse the preparation the better the retention!
This was a statistical quirk. Not even with C&B-Metabond can you expect retention to improve as the prep becomes more tapered. But the researchers nailed its real significance. The C&B-Metabond “formed a bond strong enough to mask the effect of the increasing taper.” When they pulled the crowns off, C&B-Metabond
FREQUENTLY ASKED QUESTIONS ABOUT BRUSH& BOND”
The brush is too big for some of my micro-preparations. Now what? Once you’ve stirred the liquid with the special activator brush, you can apply it with anything - a pledget, an endo microbrush, etc. So if your super small prep won’t allow the brush-head to enter, simply apply the activated liquid with something else.
Can I use Brush&Bond to bond core materials? (I’ve read that self-etchers won’t bond self-cure and dual-cure composites.) Absolutely! Though many self-etch bonding agents have problems bonding core materials and dual-cure resin cements, Brush&Bond and Touch&Bond are exceptions. They bond beautifully to light-cure, self- cure and dual-cure materials.
Can I order brushes or liquid separately? Yes.
Can I use Brush&Bond for vital pulpcaps?Pulpcapping is not one of the FDA listed applications for Brush&Bond. Amalgambond or C&B- Metabond would be a better choice for capping exposures.
I sometimes see gingival blanching where Brush&Bond contacts tis-sue. Is this something to be concerned about?No. The blanching is not painful and it doesn’t damage the tissue. Normal color should return within a day or so.
I want to use the same brush to bond several restorations. How do I do that?The brush contains enough activator to apply up to three drops of Brush&Bond liquid. However, the liquid remains active for only 3 min-utes. To avoid waste and save time when you have multiple restora-tions, it makes sense to prep all the teeth first. Then express and apply B&B to all the teeth at once. (Obviously this requires good isolation.)
When I use Brush&Bond, I prefer to etch enamel with phosphoric acid. What happens if I get acid on the dentin?Don’t worry. Brush&Bond’s performance on acid-etch dentin is virtu-ally identical to that on unetched dentin. (As with all bonding agents, the phosphoric acid must be thoroughly rinsed off before the bond-ing agent is applied.)
Can I use Brush&Bond under amalgam restorations?It depends. Brush&Bond does not adhere to amalgam, so it will not increase the retention. However, if your aim is solely to seal the tooth and prevent post- op sensitivity, Brush&Bond will perform admirably under an amalgam.
(Fig. 1): C&B-Metabond forms a resilient bond. When two bonded surfaces are forced apart, they tend to remain coated with the adhesive, and the cement film is “stretched” to failure
(Fig. 2): In contrast, most cement shows brittle failure.
tended to pull the clinical crown off the root or fail cohesively, leaving both tooth and crown covered with a film of cement. And this happened despite the fact that the bond numbers weren’t all that impressive.
Wait! Where have I heard that before? Oh yeah - in the prior study.
“In my hands ...”I’ve always liked that phrase. It bespeaks a humility I respect. “In my hands” means “What I’m going to tell you isn’t ULTIMATE TRUTH, but here’s what I’ve seen clinically...”
The European Journal of Oral Sciences reported a study that compared gap formation under composites placed by seven different dentists using 3 bonding agents.13
They noticed an interesting phenomenon. Different dentists had different degrees of success with different materials.
“It was concluded that the operator variable is a more important consideration than the material’s variable.”
In other words, the “best” bonding agent varied depending on whose hands it was in. Nothing earth-shattering I suppose. But it suggests the futility of continually switch-ing materials in search of the “best” bonding agent. Because the “best” will vary from dentist to dentist.
One other thing they noticed was that the more complex the material, the greater the variation in results from dentist to dentist. Simpler agents were more consistent from dentist to dentist.
Reference
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 prevelance 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 referrred 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 denti hypersensitivity. Reseach Monograph - Oct 03 (Available on request)
6 Suzuki S, Long-term clinical evalua-tion of a desensiter against cervical hypersensitivity. J. Dent Hlth of Japan, 49:640, 1999
7 5 Suzuki S, et al. In vitro wear evalua-tion of desensitizers for dentin hypersen-sitivity. IADR - San Antonio, Abstr #0953, 2003
8 6 Akimoto A, et al. Mechnical proper-ties of new dentin coating material. Nip Adhes Dent, 21:1, p17-23, 2003
9 Perdigao J, et al. Total-etch versus self-etch adhesive - effect on postoperative sensitivity. Jour Amer Dent Ass, 134:12, p1621-1640 Dec 03
10 Mak YF, et al. Micro-testing of resin cements to dentin and an indirect resin composite. Dent Matrls, 18:609-621, 2002
11 Zidan, Ferguson. The retention of complete crowns prepared with 3 dif-ferent tapers and luted with 4 different cements. J Prosthet Dent. 89:6, 365-571, June 03
12 Jacobsen T, et al. Effect of composi-tion and complexity of dentin-bonding agents on operator variability - analysis of gap formation using confocal micros-copy. Europ. Journ of Oral Sciences. 111:6, p525, Dec 03
