Special Report#37 - Parkell, Inc.

Touch&Bond^® makes dentists’ “Top-Ten” List

Just for fun, a number of dentists recently posted on the internet lists the dental innovations that had most significantly affected their practices during the past 12 months.

Now Parkell is no LD Caulk. You won’t hear our products touted much on the lecture circuit. Compared to the giants, Parkell products are used by a relatively modest number of dentists (We prefer to think of them as the discriminating elite). So it was gratifying to see that Touch&Bond made a bunch of lists. Furthermore, on the lists that included it, Touch&Bond occupied the #1 spot on about half of them.

Typical was this posting on genNext ...

“#1 TOUCH&BOND. This stuff has saved me hundreds of hours. You only need one set of cotton rolls for each bonding procedure. It has virtually eliminated all post-operative sensitivity. Works with just about everything. I recently had to remove a couple of Targis® crowns because the marginal ridges fractured and I had to cut them to bits because they were bonded so well.”

Matt Young, DDS
Hendersonville, NC

Different Lights for different steps

“Because there’s less chance of contamination in a fast procedure, I use Touch&Bond when it’s difficult to place a rubber dam. Otherwise, I use Prime&Bond^® NT and cure with a PAC light. (I still have a halogen light in each operatory, which I use for T&B.)

Question #1: Once I’ve cured Touch&Bond with the halogen light, can I switch to my PAC light to cure the restoration? Will the PAC-cured resin bond to T&B? Or do I have to use a halogen light for the resin as well? I’d use T&B more often if I could speed up the resin curing with my PAC light.

Question #2: I’m thinking of buying a Rembrandt Sapphire™ Plasma Arc light. DenMat claims it cures all materials, but I question its ability to cure Touch&Bond. Do you have any information or opinion on its compatibility?”

Nile P. Ersland, DDS.
Anchorage, AK

The type of light you use to cure the overlying composite won’t affect its bond to T&B. So once you’ve cured the Touch&Bond with your halogen, feel free to use your PAC light for the restoration.

I really don’t know much about DenMat’s Sapphire light. If its spectrum overlaps T&B’s absorption range by at least 20nm, the Sapphire should do the job.

Touch&Bond’s absorption range runs from about 310nm to 420nm with a peak at 380nm. So any light that gets down to 400nm or lower should cure T&B just fine.

Bonding the Captek^® crown

Got an e-mail from longtime 4-META-user Terry O’Keefe (Penfield, NY). He’d experienced a couple of bond failures to Captek crowns using TotalBond and was wondering what the problem might be. Both times the adhesive failure was on the crown side. That is, the cement stayed on the tooth when the crown came out.

Actually I think Terry had pretty much diagnosed the problem even before he wrote -”With ordinary PFM’s I always sandblast the internals before I apply the metal primer. I haven’t done that with the Capteks, however, because of the thinness of the gold layer.”

I can understand Terry’s reluctance to air-abrade such a thin layer ... nevertheless, it’s essential. In fact, blasting is probably more important with a Captek crown than with regular PFMs. That’s because the Captek coping is almost pure gold. Since it doesn’t have the typical base-metal ingredients of a porcelain metal, there’s not much for the 4-META to bond to.

When you bond Captek, you need everything possible going for you.

You must ...
1) blast the intaglio surface with 50-micron aluminum oxide
2) then apply the MTL-V primer

Abrasive blasting doubles or triples the surface area available for bonding and creates some micro-undercuts. (Don’t worry about damaging the thin metal. It shouldn’t take more than 2 or 3 seconds of air-abrasion to do the job.)

The MTL-V primer then gives the Captek a chemically-retentive surface. It chemically bonds to both the 97.5% gold content and to the 2.5% silver. And finally the TotalBond or C&B-Metabond chemically bonds to the MTL-V primer.*

INSTRUMENTS THAT WORK GREAT FOR HANDLING TOUCH&BOND PLEDGETS
(suggested by current users)

1) Hammacher^® Micro Forceps (Pearson Catalog #H04164)
2) Hu-Friedy^® Locking College Plyers (#DP18L)
3) Posterior Ortho Bracket Placing Instrument

New research seeks some evidence of “Evidence-Based Dentistry”

Do you get any “peer-reviewed” dental journals? If so, you probably know about “Evidence-Based Dentistry” (or “EBD”). Over the past 6 years, EBD has been the subject of countless editorials in research journals ... most of them lamenting the popularity of throwaway journals which are just (Hiss!) ANECDOTAL instead of (Yea!) EVIDENCE-BASED. There’s even a British publication called the “Journal of Evidence-Based Dentistry” which is the official publication of the “Society for Evidence-Based Dentistry.”

EBD is a great concept.

Who could argue with the proposition that a dentist’s clinical decisions should be based on sound evidence? The idea that there’s a hierarchy of evidence - with some kinds of evidence being much more compelling than others - is certainly valid. At the top of the list is clinical research (independent double-blind clinical studies are the gold standard of evidence.) At the bottom are anecdotes.

Problem is, there isn’t much EBD around. Not in the throwaways. And not in the peer-reviewed journals either.

One of the most knowledgeable writers on the subject of Evidence-Based Dentistry, recently wrote euphemistically that a “surprising amount of published research belongs ‘in the (trash) bin’.”¹
When I began my rant about the futility of traditional bond-strength testing back in Issue 34, I received a nice note from Dr. Michael Davis out in Arizona. He directed me to some research published by Dr. Steve Bayne of UNC suggesting that approximately 85% of all submissions to the peer-reviewed Journal of the International Association of Dental Research weren’t true research at all. At least not in the pure sense. They were basically product testing for manufacturers.

Another study by Dr. Bayne is even more depressing. After examining abstracts and citations from 1990 through 2000, Dr. Bayne concluded there isn’t even a trend toward more clinical research. In fact, unless I’m reading his numbers incorrectly, there may actually be a slight drop in clinical research.²

My advice? Don’t quit your study group.

If a product is working well in the hands of dentists you know and trust, that’s probably the most dependable evidence you’re going to find that it’ll work in your hands. Is it anecdotal? Yup. Is it “evidence-based?” That depends on your definition of evidence. But I find it a lot more compelling than the typical research paper published in a typical peer-reviewed publication.

And now, a few words to those of you who like a long track record

I was sitting around the other day; just musing (“Musing” is sort of like “thinking” only more satisfying), and it occurred to me that I haven’t written much about Amalgambond lately.

Amalgambond has been on the market since 1989. That’s 13 years. And with the exception of the HPA powder introduced in 1993, Amalgambond hasn’t been changed, modified or ‘improved’ in all that time.

Yet even today, Amalgambond remains one of our top-selling products - despite the decline in amalgam use - despite faster techniques - despite cheaper bonding agents. In fact, every week one or two dentists who’ve never bought a product from Parkell call us and order their first kit.

I then began pondering the dentin-bonding systems that have come or gone since Amalgambond was introduced (“pondering”: similar to “musing” though less satisfying). There’s Scotchbond^® 2, the entire Prismabond^® family (1,2 & 3) , DenTASTIC^®, Denthesive^® and Denthesive^® II, Dentin Bond^™, XR Bond^®, ProBOND^®, Optibond^® Fl. I could go on, but you get the point.

There’s no way to know for sure just how many amalgam and composite restorations have been bonded with Amalgambond, but my rough calculations put it somewhere around 28,000,000 - that’s right, 28 MILLION! And, as the guy who’s handled most technical calls during the past 13 years, I can testify that Amalgambond generates very few trouble-calls.

So it’s probably safe to say the stuff works.

Furthermore despite its name**, Amalgambond is a terrific composite-bonding agent. Several recent studies suggest that composite resin restorations bonded with Amalgambond show less gapping and less leakage than when much newer bonding agents are used. And this is true whether the prep features a low-stress or high-stress design - whether the composite is cured conventionally or pulsed.^3,4

So if you like the high bond strengths and massive clinical history attainable with a sequentially-applied, total-etch bonding system (and a recent poll suggests about half of you do), there’s nothing on the market that’s delivered the clinical goods for as long as Amalgambond.

By the way, we recently posted on our new website (www.parkell.com) an annotated bibliography of roughly 100 research papers involving Amalgambond, plus a number of illustrated technique articles that have appeared over the years in Parkell Today.

Okay, okay, you can cement with Amalgambond.
(But only resin crowns - and you must promise not to tell anybody.)

We’ve always been very clear in our promotional material that Amalgambond and Touch&Bond are bonding agents. C&B-Metabond and TotalBond are adhesive cements.

Fact is though, when we added the powder to the Amalgambond kit a number of years ago we inadvertently created the possibility of using Amalgambond as a cement for resin restorations. And a pretty good one at that.

I wouldn’t use Amalgambond for cementing metal restorations because everything we’ve seen suggests that C&B-Metabond is not only stronger, but it’s bond to metal is more stable. And of course, Amalgambond isn’t as easy to use or as economical as TotalBond.

But if you’re bonding a resin crown, you could do a lot worse than add some HPA powder to Amalgambond and make that your cement.

Sodium hypochlorite before bonding?

Long-time readers of this newsletter may know I’m not a huge fan of chemically “disinfecting” preparations before bonding. I’ve never seen any evidence that disinfection improved the results, and it introduces yet another possibility for contaminating the bonding surface. To me, disinfection seems like an unnecessary step that probably doesn’t help - might actually hurt4 - and certainly slows things down.

And I’m particularly uncomfortable about using bleach as general preparation disinfectant. Yes, sodium hypochlorite has a lot going for it. It stops bleeding, dissolves organic tissue, kills bugs ... oh yeah, and it’s really, really cheap.

However, bleach is a relatively strong oxidizer. And because of that, it can interfere with Amalgambond’s and C&B-Metabond’s unique TBB catalyst.

The reason TBB is the best initiator in the entire universe is because it’s extremely reactive. SO reactive, that if residual sodium hypochlorite remains on the tooth, TBB will react with it instantaneously and become neutralized.

Bottom line: The more sodium hypochlorite on the tooth, the greater the possibility that there won’t be enough unreacted TBB left to properly cure the bonding layer. And as a result, the clinical bond will suffer.****

Okay, if you absolutely HAVE to use Clorox^® on the tooth because, say, you heard about it at last weekend’s lecture, please follow these suggestions -

But first ask yourself - “Do I really want to do this?”

How some clever chemists extended C&B-Metabond’s working time without affecting the setting time or chemistry.

C&B-Metabond has been on the market in the US for 13 years ... and in Japan for more than two decades. And in all that time, nothing has even come close to matching its biocompatibility and super-adhesion. That’s not to say, however, that there aren’t a few limitations.

The three major reservations about C&B-Metabond are -

1) Expense - C&B-M may be the “BEST” - but it’s certainly not the “CHEAPEST.” Some dentists use it for everything. Most, however, save it for the really challenging stuff where traditional cements can’t cut it. (Recementations. Emergency repairs, Maryland Bridges, etc.)

2) Short working time - Until recently, even if you superchilled the mixing dish in the freezer you’d better get the prosthesis home within 2 1/2 minutes or the cement would start the setting-party without you.

3) Tedious clean-up. If you doubt our propaganda about C&B-Metabond’s incredible adhesiveness, just let it cure to completion before you start cleaning the margins. You’ll need jackhammers and dynamite.

About a year ago we replaced the old C&B-Metabond powders with something called “L-powders.” They look like the previous powders. They provide the same bond strength. They even have the same intraoral set time.

But they give you almost double the working time. In a chilled mixing dish at 54°F you now get more than 3.5 minutes to load and seat the prosthesis. If you prechill the dish in the freezer and seat it on one of those blue freezer packs, you’ll get more than 5 minutes.

5 minutes of working time? From C&B-Metabond?

You know how a spoonful of sugar dissolves faster in a cup of coffee than a sugar-cube does? That’s because sugar crystals present more surface area to the hot liquid. Rule: The greater a particle’s surface area, the faster it dissolves.

L-powders use this principle to extend the working time. Chemically, they’re exactly the same as the old powder (PMMA). And the particles are approximately the same size. The difference is that L particles are smoother. You can see that in these SEM’s.

By reducing surface irregularities, the chemists reduced the rate of dissolution ... which translates to greater working time. Once the particles dissolve, however, the setting reaction proceeds at the same rate it always did. So the intraoral setting time remains unchanged.

So that takes care of the “short-working time” complaint. Now let’s talk about the “clean-up” complaint...

You can actually SEE why L powders give you
more working time.
old particle - rough surface
new particle - smooth surface

Presenting BluSep^™ ... a brush-on film barrier that makes C&B-Metabond clean-up a snap

Think of BluSep as the “anti-bonding agent.” It’s a brush-on polymer emulsion that quickly dries to a thin, flexible film just 20 microns thick. It’s part rubber-dam/part Saran^®-wrap.

BluSep protects surfaces you DON’T want to bond to. The exterior margins of crowns, for example. Or proximal teeth. It’s slightly sticky, so it stays precisely where you put it.

Because it prevents unwanted bonding, BluSep speeds clean-up. Furthermore, the barrier film is water-soluble. When you’re finished, simply rinse it off with your water syringe.

Think what this means for post-cementation C&B-Metabond clean-up! After try-in, just brush a little BluSep onto the exterior of the crown and set it aside to dry while you apply it to the proximal teeth and gingiva.

(Just don’t get any onto the prep!)

Then bond the crown without worrying about the excess Metabond squished out at the margin. After the cement cures, you can easily remove the overflow using a conventional explorer.

Got a nice anecdote from Dr. Allen Renkoff (Union, NJ), one of the clinical evaluators in our premarket Beta Test that illustrates what BluSep is all about better than I can -

“I’d just finished bonding a crown with C&B-Metabond when I was pulled away to the telephone. When I finally got back to the patient 15 minutes later, the cement had set rock-hard. As a long-time Metabond user, I was dreading clean-up. However, I simply snapped the excess off the margins. Even the proximal material came off easily with some dental floss. This is good stuff.”

And you can use it for other things too.

If you’ve ever experienced accidental lock-on when making a direct provisional crown, you know the meaning of “embarrassment”. While simultaneously apologizing to the patient and praying to heaven it doesn’t happen a second time, you have to cut off the immobile crown ... and start all over again.

Before you fill the matrix with resin, just apply a little BluSep to the prep. The film fills subtle undercuts and bur striations that can cause lock-on. Once it dries, just seat the matrix. When you’re ready to remove the temp, it’ll practically fall out of the mouth.

Like C&B-Metabond, BluSep ain’t cheap ($19.94 per 5ml pkg.). But then again, neither is the chairtime it’ll save.

P.S. Longtime 4-METAphile Dan Peters (Grand Rapids, MI) managed to persuade our marketing guy that we had to have a blue core material that can be easily distinguished from tooth structure in the posterior. So Absolute Dentin now comes in tooth color, white, and blue. Thanks for the suggestion, Dan.

1 Southerland SE. Evidence-based dentistry: Part V. Critical Appraisal of the Dental Literature: Papers About therapy. Jour Can Dent Ass. 67:8, 442 - Available on JCDA website.
2 Bayne SC. Clinical research citations/abstracts in dentistry and dental materials. Jour Dent Res. 81: Spec Abstr #0952, A- 139, Mar 2002
3 Yoshikawa T, et al. The effects of bonding system and light curing method on reducing stress of different c-factor cavities. Jour Adhsv Dent. 3:2, p177-183, Summer 2001
4 Huffemeier S, Haller B. Effect of cavity disinfection on dentin and enamel bond strength. Jour Dent Res. 79:Spec, Abstr #2929, p510, Apr 2000

* Of course if the retention and resistance form are virtually non-existent, C&B-Metabond would be the best choice.

** Back in the ‘80’s the name “Amalgambond” made a lot more sense than the year 2002.

*** You can counteract the oxidizing effect of NaOCl, by later treating the tooth with a reducing agent like ascorbic acid. But just how complicated do you want to make your life?