Presenting the first 4-META-based adhesive endodontic sealerparkell.host4kb.com/getAttach/267/AA-00349/Adhesive+Newsletter_… · adhesives1,2,3,4 and you can’t get any deeper than

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FROM the ARCHIVES

From the day we introduced C&B-Metabond® we’ve tried like the devil to figure out some way to

use 4-META’s extraordinary abilities to improve endodontic fills.

Unlike most adhesives, C&B-Metabond loves moisture… in fact, it actually sets better in a slightly moist environment. That’s an obvious plus for bonding to canals which are difficult-to-impossible to completely dry. Studies consistently show that C&B-Metabond adheres to deep dentin more effectively than other adhesives1,2,3,4 and you can’t get any deeper than canal dentin. And it seals the exposed dentin with an acid-resistant hybrid layer that’s extraordinarily effective in preventing leakage.

The problem that baffled us was how to easily and reliably deliver C&B-Metabond to the entire canal before it started to set.

Now, almost 16 years after C&B-Metabond first came to the US, the research team that created Brush&Bond has come up with a 4-META sealer that not only delivers the benefits of C&B-Metabond, but does it using an extremely easy technique.

It’s called MetaSEAL™, and as you can see, its protective hybrid layer is virtually indistinguishable from C&B-Metabond’s.

Its self-etch formula means you don’t have to prime or etch the canal walls. After completing conventional canal preparation, simply mix 3 drops of liquid with one level scoop of powder. Fill the canal with sealer using a point or lentulo between your fingers. Then coat the master point and seat it.

Works with any cold obturation technique Though a number of dentists in our Beta study reported success using MetaSEAL with ThermaFil, we’re recommending it primarily for use with cold obturation techniques – either single point or lateral condensation.

Using a super-hot instrument causes the sealer to set too quickly... and in endodontics the slower the resin sets, the better the seal.

Why MetaSEAL’s slow set is a very, very good thing When resin cures in a confined space (and I can’t imagine a more confined space than the gap between an endodontic point and the canal wall), there’s massive poten-tial for high shrinkage-stresses to develop. These stresses can pull the resin away from the canal walls, preventing effective bonding and allowing leakage.

The faster a resin sealer sets – the greater this stress.

So MetaSEAL sets slowly in the canal. Very slowly. At body temperature, it takes up to 16 hours for MetaSEAL to achieve maximum hardness. As it slowly polymer-izes, its high plastic flow prevents stress build-up. So instead of pulling away from the canal walls, the monomers infiltrate into the radicular dentin.

And that’s where it polymerizes first. Most resins hate moisture. MetaSEAL loves it. In fact, its unique self-cure catalyst requires a little H2O in order to initiate setting. As a result, the sealer cures first within the damp dentin along the canal.

Create an instant coronal seal Once you’ve finished your fill, just zap the surface with any curing light. MetaSE-AL is dual-cure, so this irradiation creates an instant coronal seal – even while the resin in the canal is slowly self-curing.Turn any point into an “adhesive point” MetaSEAL doesn’t just bond to dentin. As you might expect, it also bonds to Resi-lon™ polymer points. But it also bonds to gutta percha – and even silver points.And it’s surprisingly economical Though the MetaSEAL kit isn’t exactly cheap – $119.95, it contains enough mate-rial for 50-75 canals.

You can’t tell a bond by looking at the etch pattern

There’s a rash of ads for self-etch bonding agents showing micrographs of their etch patterns to “prove” how well they bond to uncut enamel. Many of these ads also brag about how low their pH is. The latest in the series is Prompt®.

It’s funny how once things become ac-cepted, they’re hardly ever questioned. Like the canals on Mars late in the 19th century. Or the manifold dangers of coffee late in the 20th. Or enamel bonding in the 21st century.

Everybody knows you put acid on enamel to create an etch pattern, right? And once you create an etch pattern, resin can flow into this pattern creating little fingers that lock in place to produce the bond, right?

Maybe. But increasing evidence suggests that an enamel etch-pattern is not essential to a good bond. In fact, great bonds can be achieved to enamel that shows very little etch.

Like C&B-Metabond (Fig. 2) MetaSEAL seals the dentin with a dense 4-Meta hybrid layer (Fig. 1), that starts polymer-izing within the moist dentin.

Fig. 1

Fig. 2

Adhesive Newsletter: Issue #52

Presenting the first 4-META-based adhesive endodontic sealer•Self-etch, so there’s no etching... no priming •Seals and bonds to canal walls with a 4-META hybrid layer •Bonds to gutta percha points, polymer points... even silver points From Nelson Gendusa, D.D.S. - Director of Research

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The First-Molar Conundrum A bunch of studies suggest that the amount of aprismatic enamel is higher on posterior teeth than anteriors, so the quality of the etch pattern decreases as you move posteriorly. (Even on anteriors an ideal etch-pattern almost never occurs on more than 5% of the surface.)

One study performed in England found that after etching with 37% phosphoric for 30 secs, about 27% of a central’s surface area shows some kind of etching. In contrast, only 7-11% of a first molar shows any etch pattern at all.

Now here’s the conundrum: The etch pattern on the upper and lower 1st molars is roughly the same. Yet bond strength to the lower first molar averages more than twice the bond strength to the upper first molar. In fact, #19 and #30 shows the highest bond strength of all teeth in the arch – and #3 and #14 consistently show the lowest.

Two teeth. Both show the same amount of etching. Yet, the bond strength to one tooth is more than twice that to the other.5

One recent microscopic study of self-etchers clearly showed that one agent created an almost phosphoric-acid-like etch on enamel, while another’s effect was scarcely noticeable. This is exactly what the researchers expected since one agent was more acidic than the other.

However they had a lot of trouble explain-ing the results of their bond strength tests.

The agent with a weak etch, showed almost twice the enamel bond strength of the agent with the visible etch pattern.

In their words: “Other factors apart from the etching pattern may play a role in the bond strength values.”6

Possible Explanation: Acid certainly plays a part in creat-ing an enamel bond – but not because it creates a well-defined etch pattern. Acid exposes the crystallites in the surface, making the enamel permeable – so it can absorb the resin molecules. The same acid treatment that makes the enamel permeable, also creates an etch-pattern on cer-tain parts of the tooth. But it’s the permeability – not the etch-pattern – that creates the bond.

Incidentally, this is the precise model my bud Nobuo Nakabayashi proposed about 20 years ago – and like many of his predictions, he’s only now being proven correct.

Getting back to those ads that brag about their acidity. The ads don’t mention the darker side of acidity. For example, highly acidic self-etchers tend to be incompatible with dual- and self-cure materials and resin cements. So you can’t use them for bonded cores or with bonded crowns.

The greater the acidity, the greater the complexity of technique and the more im-portant it is that you precisely follow the technique. And if you don’t, the greater the opportunity for post-op sensitivity.

So you don’t have to take our word for it –

We’ve just posted an annotated Brush&Bond® bibliography on our website. The link is posted on the Brush&Bond page. By the way – none of the posted research was conducted or paid for by Parkell.

Strengths and weaknesses of Parkell Adhesives

I received a note from Dr. Rob Waldman concerning a recent Brush&Bond ad that included a table comparing the virtues and limitations of different bonding agents. He asked if we could do a similar table comparing Parkell adhesives. He said he used a lot of our stuff, but wasn’t sure he was using the proper product for a specific application.

So Rich and I sat down and, after some arguing, came up with this list of what we consider “the best” adhesives for various applications. I put “the best” in quotations because there’s a lot of subjectivity here. We’ve included the specific features and limitations that influenced our decision.

For example, independent research has shown that Amalgambond is extremely effective in relieving cervical sensitiv-ity. With its 17-year clinical history, I couldn’t argue with anyone who routinely used Amalgambond to treat hypersensitivity. Nevertheless, we ranked Brush&Bond a bit higher than Amalgambond. Here’s our thinking: Brush&Bond is a self-etcher, so it’s faster to use. (Score one for B&B.) More important, if a patient is highly sensitive, acid-etching cervical dentin with open tubules can be uncomfortable. (That’s another score for B&B). And finally, B&B’s polymer film is tougher than Amalgambond’s, so it’s probably less likely to wear off.

Anyway, here’s the table – see if you agree with us. (See pages 3 & 4)

Sticking with Amalgambond

I’m a great believer in Amalgambond. My one problem over the years has been its sticking the restoration to the matrix. I have tried Vaseline® and ChapStick®, but have had only limited success.

Do you have any other suggestions?

– Dr. George Ellsberry Columbus, MS

Wax crayon… grease pencil… cavity varnish… Blu-Sep.

Methacrylate-sensitivity and reality

“Not to be used on any patient known to be methacrylate-sensitive.”

That copy – or something very much like it appears in the instructions for virtually all bonding agents, composites and provisional materials. However, the phrase “known to be methacrylate-sensi-tive” leaves a question – What about the methacrylate-sensitive patients who don’t know about their allergy?

Which one of these etched surfaces provides a stronger enamel bond? Are you sure?

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Application Recommendations Reason for recommendation Negative considerations

CERVICAL #1 Brush&Bond Self-etch formula eliminates need to etchDESENSITIZATION sensitive dentin (potentially painful)

Tough film resists wear

Easy, fast technique

Independent documentation oflong-term desensitization

#2 Amalgambond Independent documentation of desensitizing Requires etching of sensitive dentin(potentially painful)

Polymer film slightly less wear-resistantthan Brush&Bond’s

#3 Touch&Bond Simple technique (but not as simple as Clinical feedback suggests that B&B isBrush&Bond) more effective

Film is subject to wear, which suggestsT&B treatment may have to be repeatedmore frequently

Application Recommendations Reason for recommendation Negative considerations

COMPOSITE #1 Brush&Bond Probably the fastest, simplest technique Bonds to unetched dentin and cutBONDING available (35secs) enamel, but uncut enamel must be etched

Light-cure One of the few self-etchers that bonds to Self-Cure all 3 types of composite (light-cure, self-Dual-Cure cure, dual-cure)

#1 (tie) Amalgambond Longest clinical history of any bonding Dentin and enamel must be etchedagent currently on the market

#2 Touch&Bond Tiny applicator sponge fits into Takes longer (1min) to bond thanvery small preps B&B (35 secs)

One of the few self-etchers that bonds to Bonds to unetched dentin and cutall 3 types of composite (light-cure, self- enamel, but uncut enamel must be etchedcure, dual-cure)

Requires a halogen curing light (not LED)

In vitro bond strengths lower than B&B*

* However, there’s no evidence that the difference in bond strength is clinically significant.

AMALGAM #1 Amalgambond Strong bonds to amalgamBONDING

Supported by extensive independentresearch

#2 C&B-Metabond Strong bonds to amalgam More expensive than Amalgambond

DESENSITIZING #1 Amalgambond Extensive independent documentation of Requires etchingLINER UNDER desensitizing propertiesAMALGAM

Simultaneously desensitizes and bonds theamalgam to provide retention

#1 (tie) Brush&Bond Simple technique (self-etch) Does not bond the amalgam to tooth structure

Reliable desensitization

#2 Touch&Bond Does not bond the amalgam to toothstructure

Clinical feedback and lab studiessuggests that B&B is more effective as adesensitizer

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5

PROTECTION OF #1 Brush&Bond Robust film prevents patient discomfortPREPS DURING during removal of the temp andPROVISIONAL cementation of the final crownPERIOD

Simple technique

Supported by extensive independentresearch

#2 Touch&Bond Simple technique (but not as simple as B&B) Provides less protection than B&B

VITAL PULP CAP #1 C&B-Metabond FDA-certified for pulp caps

Supported by extensive independentresearch

Probably the most biocompatible of allresin adhesives (Contains no HEMA, BisGMA,TEGDMA or other components found tobe pulpal irritants)

Green etchant contains ferric chloridewhich tends to stop pulpal bleeding

#2 Amalgambond FDA-certified for pulp caps Less research documentation as a pulp cap than C&B-Metabond

Green etchant contains ferric chloride which tends to stop pulpal bleeding

CROWN CEMENTATION(On low retention #1 C&B-Metabond Provides the “mother-of-all-bonds” Bond is so strong that if removal is prep) to dentin and metal necessary, the crown will probably

have to be sectioned

#2 TotalBond Easier Technique Bond strength is good, but nothinglike C&B-M’s

#3 Brush&Bond plusresin cement

Application Recommendations Reason for recommendation Negative considerations

POST C&B-Metabond Powerful bond plus self-cure makes this Requires etchingCEMENTATION the adhesive-of-choice for short posts or(which adhesive is cementation into roots that have been“best” depends on severely weakened.specific condition)

Brush&Bond plus Very simple technique (no mixing or etching)Absolute Dentin

B&B can be applied and effectively light-cured in post holes up to 10mm deep

Absolute Dentin can be used for both postcementation and core build-up

TotalBond Good bond Not as easy to use as B&B/Absolute Dentin

Easier to use than C&B-Metabond Requires etching

COMPOSITE #1 Add&Bond Excellent bond to old composite (also Does not bond to dentinREPAIR bonds to etched enamel)

#2 Brush&Bond Good bond to old composite, and also Not as strong to old composite asbonds to dentin and cut or etched enamel Add&Bond

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In reality, reactions to methacrylate dental materials are rare.

Even patients who show a positive patch-test rarely react to their composite restora-tions. This is fortunate, because for those who are seriously methacrylate-sensitive, dentistry doesn’t offer many good alternatives. Virtually every bonding agent, composite, denture acrylic, sealant, and provisional material contains methacrylate.

It’s not exposure to the large PMMA molecule that’s the problem with meth-acrylates. It’s exposure to the smaller unreacted monomer molecule. That’s why dentists, assistants and technicians are much more likely than the patient to develop MMA allergies. They have much more contact with the unpolymerized material than the patient does.

In rare cases, a patient may demonstrate contact dermatitis after exposure to a di-rect provisional bridge. When this occurs, the problem can often be resolved by removing the bridge and post-curing it in a toaster-oven or hot water to reduce the free monomer – and then recementing it.

Over the years most of the calls I’ve received concerning potential allergic reactions to our MA-containing materi-als proved to be false alarms. One turned out to be a reaction to the dentist’s latex gloves. A couple were tissue burns. (Rule of thumb: If an apparent tissue reaction appears while the patient is still in the chair, it’s probably a burn – not an allergic reaction.)

Though several calls I’ve received remain a mystery, I strongly suspect they were anxiety attacks. They’re scared... they smell the bonding agent/provisional material, etc.... they panic.

So Brush&Bond® is earning respect as a cervical sealant... What about B&B as an occlusal sealant?

Several issues ago we printed a dentist’s comment that she was now using Brush&Bond under all her occlusal sealants.

Her reasoning: After opening up a fissure she frequently found previously unde-tected caries. In her effort to remove them, she could never be positive that she’d

eliminated every scintilla of caries or be certain that she hadn’t penetrated the DEJ in the attempt.

So to her it made sense to use one of the few dentin/enamel bonding agents that had been shown to penetrate and “fix” carious tissue.7,8,9

This exchange triggered another interest-ing question – Suppose you’re applying the bonding agent to the pit/fissure prior to the sealant. Why exactly do you apply a sealant over it? To protect against acid and plaque penetration? A number of studies have shown that B&B resists acid, right?10,11 And other studies suggest it creates a hard surface that resists abrasion.12,13

A team of researchers at Munich’s Ludwig-Maximillian University recently compared Brush&Bond’s properties to those of several popular sealants.14

A good sealant should be hard, so they compared the materials’ Vickers hardness.

It should be stiff – so they measured their modulus of elasticity. And it should resist mechanical wear, so they subjected the material to a 3-surface wear test.

And Brush&Bond scored higher than the fissure sealants in all three categories.

It formed a harder surface – a stiffer surface – and it even showed slightly less wear (Though admittedly there wasn’t much difference in the wear category.)

Don’t misunderstand – I’m not suggesting you toss out your sealants. Extensive work will be required before we’d suggest that a simple application of B&B eliminates the need for traditional sealing protocol. But it does make you think.

Brush&Bond and self-etching cements

I was listening recently to one of den-tistry’s most respected speakers. He was quite complimentary about the 4-META adhesives in general, but he absolutely raved about Brush&Bond. It was an outstanding recommendation!

As someone who originally beta-tested Brush&Bond about 5 years ago, I love the stuff. After all those years of use, I’ve had just a couple of sensitive teeth. By the way, when bonding with Brush&Bond I no longer use bases under my composites

Is there any advantage to using Brush&Bond under RelyX™ Unicem® or would it weaken the bond?

– Jim Proctor, DDS Memphis, TN

I know a number of dentists who routinely apply B&B before they cement with Uni-cem. A couple of studies have suggested that Unicem reacts primarily with the surface of the tooth, and doesn’t develop a traditional hybrid layer. Furthermore, the bond develops relatively slowly. By applying B&B before cementation, they feel more comfortable that a hybrid layer is protecting the tooth and the early bond will be better.

Okay, JKiii, you win.Brush&Bond demo now on the web!

Over the years I’ve given my colleague John Kanca a good deal of ribbing concerning his video demonstration of self-etch bonding. In my opinion, any dentist who needs a video to understand the self-etch procedure is using the wrong self-etcher. If you can fall off a log, you should be able to use a self-etch bonding agent.

Or so I thought. However one incredible telephone call has caused me to reconsider.

Dentist: I’m thinking about using Brush&Bond to protect my crown preps. Could you go over the technique?

Me: Actually the technique is exactly the same as what you’re doing for bonding. Just apply a drop of B&B liquid with the special brush ... let it sit there for 20 seconds... blow it dry ... and cure it for 10 seconds. Done.

Dentist: (long pause) Special brush? What special brush? We didn’t get any special brushes. (Yelling to someone in the office) Susan, we didn’t get any brushes with Brush&Bond, did we? Nope, no brushes.

Me: If you ordered a Brush&Bond kit, you got brushes. They’re in a black tube.

Dentist: Black Tube? Susan, is there a black tube in there? ... Well, open it.

Me: (Speaking very slowly, like I do to my grandchildren) If you look in the instruc-tions you’ll see that -

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Dentist: Instructions? We didn’t get any instructions. (Yelling) Susan, are there any instructions in the Brush&Bond box? Oh. (Talking to me again) So you really have to use those brushes?

Me: If you want the stuff to work.

Dentist: Hmmm. Do you think that might be why some of my cores came out?

My first inclination was to inform him that as the only dentist ever to flunk our “falling-off-a-log” test, he must imme-diately surrender his Brush&Bond and swear never, ever to buy anything from Parkell again.

Then I had a better thought.

We now have posted on our website the official Brush&Bond real-time “how-to” video. It runs 37 seconds, and consists mostly of watching B&B sit on the tooth for 20 seconds. In addition, there will soon be a special introductory video dem-onstrating how to open the black tube and discover the Brush&Bond brushes. (I’m serious about the “How to” video – but joking about the “black tube” video – I think.)

To watch it go to our website (www.parkell.com), click on the “Brush&Bond” picture and then “video.”

References1 Yang B, et al, Micro-tensile bond strength of three luting resins to human regional dentin. Dntl Matrls. 22:p45-56, 2006

2 Eldeniz AU, et al. Effect of laser treatment on bond strengths of 4 resin cements to root ca-nal dentin. Jour Dental Res. Spec Ed-Goteburg, June 03

3 Tagami J et al. Correlation among dentin depth, permeability and bond strength of adhesive resins, Dent Matrls, p45-50, Jan 90

4 Tao L et al. Effect of depth and tooth type. Jour Dent Res. 69:Spec, Abstr #1411, Mrch 90

5 Hobson RS, McCabe JF. Relationship between enamel etch characteristics and resin-enamel bond strength. British Dent Jour. 192:8, p463-468, Apr 02

6 Moura SK, et al. Does the acidity of self-etching primers affect bond strength and surface morphology of enamel? The Jour of Adhsv Dent. 8:2, p75-83, Apr 2006

7 Nakamura K, et al. Bond strength to carious dentin using thin-film bonding agents. IADR-Baltimore, #0495, Mar 05

8 Otsuki H, et al. Bond strength of thin-film bonding agent to caries-affected dentin. International Congress on Adhesive Dentistry. Abstr #P-086, p443, Aprl 05

9 Wakamatsu S, et al. A study of self-polymer-izing catalyst in one step adhesive. AADR-Orlando, #1828, Mar 06

10 Fukagawa Y, et al. Prevention of second-ary caries by self-etch bonding system . Inter Symp on Dntl Hygiene, Madrid Jly 04

11 Tanaka H, et al. In vitro evaluation of a resin-coating technique for caries prevention. IADR- Baltimore. Abstr#0516. Mar 05

12 Akimoto N, et al. Mechanical properties of a new dentin coating material. Japn Soc for Adhesv Dent. 21:1, p17-23, 03

13 Suzuki S et al. In vitro wear evaluation of desensitizers for dent hypersensitivity. IADR- San Antonio, Abstr #0953, 03

14 Dananoglu A, et al. Comparison of the mechanical properties of resin-based adhesives and fissure sealants.