Treatment Planning
There must be 50 ways to fix a facing.
How to tailor the repair to the specific fracture.

by Nelson J. Gendusa, D.D.S.
Director of Research

The idea that a specific dental problem has a unique “correct” solution is just plain obsolete. Creative dentists are discovering that 4-META-based adhesives (Amalgambond® and C&B-Metabond®) are opening a new world of treatment options ... providing simple, low-cost solutions that were unthinkable just several years ago.At first glance, most fractured facings have a lot in common. They often occur in the anterior... where they’ll cause maximum patient distress. They frequently fracture right down to the metal substructure. And for some arcane reason I’ve never been able to understand, fractures almost always occur in an otherwise sound bridge ... never in an old prosthesis you were planning to replace anyway.

Despite these similarities, all fractures are not the same, and the “best” treatment for a fracture can vary significantly from patient to patient.

Here are a few things to consider when deciding which way is “best.”

Remember, the original porcelain-to-metal bond was almost certainly stronger than any repair you can make. So before you start, you should attempt to determine what caused the fracture. Was it a recurring event (say a traumatic prematurity during an excursion?) Or was it a design flaw in the bridge? If you don’t eliminate the cause, the fracture will probably recur.

Economic constraints vary from patient to patient. (Some dentists might argue that economics should not significantly influence the treatment. Get real!)
And even the cosmetic objective may vary. Some patients will be satisfied only with “magnificent” cosmetics. Others will be delighted with “pretty good” cosmetics.
To illustrate what I’m talking about, here are four instances of fractured facings that I ran across in my files. They show how adhesives allow the dentist to tailor the repair to the specific patient.

REPAIR #1: A LAMINATE FOR MAXIMUM ESTHETICS, LONGEVITY

For this young patient, the dentist chose a bonded porcelain laminate. After reducing the porcelain to create room, he cemented the laminate using C&B-Metabond. (Case courtesy of Dr. Allen Weiner - Medfield, MA)

REPAIR #1: Maximum esthetics. Maximum longevity. Maximum cost.

A mother was smacked in the jaw by her young daughter’s head. The result was a nasty fracture on the central unit of a beautiful 3-unit bridge. Other than the fracture, the 5-year old prosthesis was in perfect shape.

So let’s see what the dentist knew ...
1.) The patient was young and female. Esthetics and longevity were important.
2.) The fracture was caused by a traumatic event, not likely to recur.
3.) The bridge was in excellent condition, suggesting that it would not require replacement in the immediate future.

The dentist elected to repair the fracture with a bonded ceramic laminate. This is a fairly expensive repair, but for this patient, the cosmetic result, its permanence, plus the expectation that the bridge would have a long functional life meant the laminate was well worth the investment.

After carefully reducing the porcelain with a coarse grit diamond to create room, he took an impression and sent it to the lab. The laminate was fabricated of a fairly opaque porcelain (Jelenko PVS®). The opaque nature of the porcelain was important in this case, because the dentist intended to bond the laminate with C&B-Metabond. C&B-Metabond comes in just 2 colors ... clear and opaque ... so it does not allow the dentist to adjust the shade with tinted luting agents.

At the cementation appointment, the dentist air-abraded the crown to increase the surface area. He etched the porcelain remaining on the crown using hydrofluoric acid, and then silanated both the porcelain on the crown and the inner surface of the laminate.*

Finally, he cemented the laminate using clear C&B-Metabond. As you can see, the result is every bit as esthetic as the original units ... and he tells us that 7years later, it looks as good as when it was inserted.

REPAIR #2: GOOD ESTHETICS, ECONOMY

For this middle-age male, the fracture was repaired using direct bonded composite. The result was
adequate esthetics and longevity in a one-appointment repair.

REPAIR#2: Good esthetics. Adequate longevity. Low cost.

Here a similar fracture was repaired by a different dentist using a direct composite. This patient was a middle-aged man, not nearly so concerned with esthetics.

The fracture had occurred several years previously and had already been repaired once without using a 4-META adhesive. The patch had leaked badly, causing extensive discoloration.

The dentist removed the old composite and created a long tapered bevel into the porcelain. When repairing a fracture with direct composite, it’s always smart to prepare a long bevel. That way you’ll have enough porcelain surface to achieve a strong bond and you’ll avoid an abrupt junction between composite and porcelain. The two materials never match precisely, so the bevel creates a blended transition that’s less noticeable.

The surface to be bonded was blasted with the Aeroetcher (see page 3). Then the porcelain bevel was etched with hydrofluoric acid and silanated ... and the exposed metal was painted with C&B-Metabond.

After the cement had cured rock hard, and the dentist could hear an explorer scraped over the surface, he adjusted the color with a tinted unfilled resin and rebuilt the defect using composite.

Not the gorgeous cosmetic result we saw in the previous repair ... but the patient was pleased.

REPAIR #3: VERY FAST AND VERY ECONOMICAL

Major dentistry was out of the question for this retired patient. So the dentist repaired the broken
facing using composite and C&B-Metabond ... in about 30 minutes. (Picture to the right was taken 6 years after the repair.) (Case courtesy of Dr. Allen Weiner - Medfield, MA)

REPAIR#3: Fast and very economical.

A retired 70-year-old male lost a Steele’s facing from an old bridge.

His health was poor, economy was a major concern and he had no desire to replace the bridge.

Actually, this repair was probably the easiest of the four illustrated here, since it involved bonding to just one substrate ... metal.
So the dentist simply blasted the surface and applied a thin layer of C&B-Metabond. He mixed the cement using the opaque powder in order to mask the metal. After it had cured completely, he rebuilt the facing using composite opaquer, a hybrid for strength and a microfill veneer to improve polishability.

In this case, economy was a major concern ... and adhesives allowed the dentist to provide a simple, low-cost solution to the patient’s problem ... all in about 30 minutes.

REPAIR #4 LEAVING YOUR OPTIONS OPEN

If you don’t know what caused the fracture, avoid a major investment in the repair. If this fracture was due to flexing, the bonded composite will almost certainly require replacement. (Unfortunately, the dentist used C&B-Metabond’s clear powder, which allowed some metal show-through.)

REPAIR#4: Leaving your options open.

In our final example, bonded composite was selected because the dentist had suspicions concerning the origin of the fracture.
As I mentioned, one of the first steps in treating a porcelain break is determining the cause. If it’s a single traumatic event (like the head-to-head collision in our first example), the chance of recurrence is minimal. But if it’s an ongoing problem, you’ll probably be seeing that patient again.

A cervical fracture like Case 4 can be difficult to permanently repair, because it’s often caused by a design flaw in the bridge.

Occasionally a long-span bridge will flex under occlusal load, causing the marginal area of an anterior abutment crown to briefly distort. The result is a fracture exactly like the one in Case 4. The dentist’s suspicions were supported by the fact that the patient couldn’t recall anything that might have caused the fracture.

The dentist repaired the cervical fracture with a 4-META-based adhesive and bonded composite, because he suspected the repair might prove temporary.

If he is wrong, the composite patch will provide acceptable esthetics for years ... until it eventually begins to wear.
But if his suspicions are correct, and the composite subsequently pops off, he won’t have wasted the patient’s money on an expensive repair.

There’s a world of new options for your consideration.

Dentists have always had to wrestle with alternatives when they develop a treatment plan. (Fixed restoration or removable? Large amalgam or full crown?)

So dentistry has never really been a “true/false” test, with one correct answer per restoration. But with today’s adhesives, the number of options has increased dramatically. If you’re limiting yourself to the old solutions, you may be missing a terrific opportunity to tailor your treatment to the unique needs of that particular patient.

If dentistry were a test, it would definitely be multiple choice. And in many cases, the correct answer would be “All of the above.”

* Instead of acid and silane, the dentist could have painted the porcelain surfaces with Etch-Free. This 4-META-based primer allows C&B-Metabond to adhere to unetched porcelain.

For more information on C&B-Metabond click here.