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Within the next five years or so, a gaping hole
in oral health care will be filled, so say a number
of dental educators and researchers leading the charge
for minimally invasive care. Some, in fact, question
the ethics of following the traditional "drill
and fill" model of dentistry now that the bacteria
that cause caries can be detected earlier and treated
with antibacterial agents, and early carious lesions
can be reversed—all without surgical intervention.
Though the question remains whether the dental profession
will adapt in a timely fashion, several recent innovations
and a number of upcoming technologies hold promise
for a smoother transition to this new paradigm.
By Dennis Spaeth
In 1896, Dr. G.V. Black predicted the demise of his
own legacy to dentistry—extension for prevention,
the very roots of modern dentistry that he fathered.
Black suggested that dentists one day would be "engaged
in practicing preventive, rather than reparative,
dentistry." Now, it's not as if he held Nostradamus-like
abilities, but Black—who spent years studying
dental pathology and bacteriology—envisioned
a day when the profession would understand the
etiology and pathology of caries well enough "to
combat its destructive effects by systemic medication."
Well, a century has come and gone, and the profession
is still waiting for the new modern dentistry, right?
Don't bet your malpractice insurance policy on it.
Not only is it possible to use a combination of antibacterial
agents and topical fluoride treatments to both halt
and reverse caries, some argue that this is the new
standard of care.
And that's just the entry to a whole new paradigm
for dentistry: minimally invasive care. Sure, you
can still practice what you learned in school for
carious lesions that still require restoration—just
not so much that whole extension-for-prevention concept
fostered by Black in the 1800s. Today's dentistry
allows you to conserve more healthy tissue than ever
before. Actually, this day likely arrived about 10
or more years ago with the advent of adhesives, suggest
federal health officials.
"In future years," noted a U.S. Public
Health Service document published in January 1993, "the
restoration of cavities will cease to be the mainstay
of general and pediatric dentists. Treatments emphasizing
conservative and preventive approaches should be
expected. New adhesives and more durable plastic
restorative materials that are currently available
allow for increasing use of minimally invasive procedures
that are more preventive than restorative. Preventive
rinses allow remineralization of early lesions on
tooth crowns and roots and should be used increasingly."
In 1997, Dr. Harold C. Slavkin, then the director
of the National Institute of Dental Research (now
National Institute of Dental and Craniofacial Research),
echoed the sentiments. "We are now faced with
the possibility that the ways in which we approached
the solution to these oral and craniofacial health
problems in the past have now been surpassed by a
logic that has its roots in the intersection of cell
and molecular biology, information sciences, mathematics,
bioengineering, and materials and implant science.
"The quest for us now," wrote Slavkin, "becomes
the design and fabrication of biological solutions
to the oral health problems that we face in the clinic
on a daily basis. And ... the application of biological
approaches to restorative dentistry in the repair
of tooth structure destroyed by the infection from
Streptococcus mutans."
Researchers from across the country, in fact, have
spent the better part of the last two decades building
the scientific foundation for minimally invasive
dentistry. So even if you missed the death knell
for Black's "modern dentistry," researchers
and clinicians contacted by Dental Practice Report—from
Pennsylvania and Maryland to California and Oregon—are
prepared to guide you through this paradigm shift
and provide you with some perspective on the myriad
technologies and products available today and those
just around the corner that promise to make the transition
easier.
The New Paradigm
Researchers from the University of Michigan School
of Dentistry proclaimed in the January 2003 issue
of the Journal of the American Dental Association
that "the management of dental caries has evolved
from G.V. Black's 'extension for prevention' to 'minimally
invasive.'" The researchers, Drs. Carol Anne
Murdoch-Kinch and Mary Ellen McLean, cited as evidence
of this shift new dental restorative materials, improved
dental adhesives and a growing understanding of the
caries process.
Even Black's caries classification system seems
destined for the scrap heap in this new brand of
dentistry. "Traditional cavity preparations
were designed at a time when carious lesions usually
were diagnosed at a more advanced state than are
the incipient lesions dentists detect today," noted
Murdoch-Kinch and McLean.
Now, the JADA article was not a plume of white smoke
above the Sistine Chapel indicating the official
arrival of a new standard. Actually, if they did
that sort of thing, you might have noticed it five
or more years ago when a number of dentists began
practicing minimally invasive dentistry. The problem
is the majority of dentists think this is still a
futuristic concept.
So says Dr. Stewart Rosenberg, of Laurel, Md., who
co-founded the World Congress of Microdentistry,
which was formed about five years ago by a number
of clinicians, researchers and educators from around
the world to facilitate a better understanding of
the minimally invasive approach to dental care.
"Minimally invasive dentistry has always been
the goal of dentistry," Rosenberg explains, "but
nobody ever made an attempt to practice it. Everybody
said they wanted to practice minimally invasive dentistry,
but what did we do for the vast majority of time
I've been in practice (since 1966)? We waited until
there was a big hole in the tooth and then we filled
it.
"And that's still what's being taught in dental
schools," says Rosenberg.
That point is not lost on Murdoch-Kinch and McLean. "Some
dentists still find it difficult to change their
mind sets ... and are continuing to cut large, traditional
preparations. This apparent lag in adoption of new
clinical practices based on scientific evidence is
supported by the recent finding that 72 percent of
states allowed a lesion confined to enamel to be
restored as part of the requirements for clinical
board examinations," the Michigan researchers
observed, citing a September 2001 article in Critical
Reviews in Oral Biology & Medicine.
That article posed the question, "Is it time
to change state and regional dental licensure board
exams in response to evidence from caries research?" The
authors conducted a survey to learn whether Class
2 tooth preparations for carious lesions with radiolucencies
confined to enamel were allowed for state and regional
exams. They found that 33 states allowed teeth with
either an E1 or E2 lesion to be restored. Only 12
states did not allow such lesions to be surgically
treated.
In fact, there are those who question the ethics
of allowing a restoration of any early carious lesion,
let alone one for a board exam. Among them is Dr.
Doug Young, associate professor in the Department
of Diagnosis and Management at the University of
the Pacific, San Francisco, School of Dentistry.
If dentists still must be tested on whether they
have the necessary skills to perform a restoration
on an early carious lesion, "perhaps they should
be done on a typodont, not a human being because
of the ethics involved," says Young, who is
spreading the word about a caries risk assessment
system developed in California that would allow dentists
to identify the risk of caries much earlier and treat
it non-surgically.
State dental boards, continues Young, are still
testing on the G.V. Black preparation design. "That
is a huge concern because ethically some of these
lesions that are being accepted for the board should
not be drilled at all knowing what we know now about
remineralization."
To Rosenberg, modern dentistry and its extension-for-prevention
philosophy has always meant "extension for ruining
teeth." Rosenberg hopes to help change that
mind set as the current president of the World Congress
of Microdentistry. "We don't have to over-prepare
teeth," he observes.
Dentists who practice minimally invasive care, explains
Rosenberg, treat dental disease as a bacterial infection.
They use early caries detection devices such as DIAGNOdent
(KaVo America Corp.) or caries indicator dyes (which
will be addressed in the October issue); they use
antibacterial agents such as chlorhexidine to bring
down the level of streptococcus mutans, and then
fluoride treatments to remineralize early carious
lesions. For the lesions that require restoration,
these dentists use microburs, air abrasion and hard-tissue
lasers. "Selective caries removal" is the
new buzz phrase.
"Using these wonderful technologies, like the
Biolase YSGG laser (Waterlase®), we can treat
teeth and tissues minimally invasively without trauma,
without pain and often without anesthesia," adds
Rosenberg. "So we really have a tremendous number
of technologies that exist now that we didn't have
that are literally changing the face of dentistry
worldwide."
"I think the more tools we have at our disposal,
the better off we are to do the best dentistry we
can do," continues Rosenberg. "There are
times that on one tooth I will use the laser, air
abrasion, a bur and a spoon excavator. You need to
have all these things."
As convinced as some in dentistry are that minimally
invasive dentistry will become the standard of care
within the next five years, others like Dr. V. Kim
Kutsch, of Albany, Ore., aren't so sure. A founding
member and the first president of the World Congress
of Microdentistry, Kutsch says he "strongly
believes" this new approach will become the
standard of care in dentistry, "but it may take
10 years or more to penetrate the profession on a
large scale."
Already, observes Kutsch, "minimally invasive
care is a standard of practice in a growing number
of practices in the United States." Optimistically,
Kutsch adds he believes dentists will be proactive
in adopting this new paradigm because it is ultimately
in the best interest of patients.
Plus, he says, technological innovations are making
it easier than ever for dentists to practice minimally
invasive dentistry. "From a technological standpoint," he
says, "all the materials and technologies that
have been developed in the last 10, 12, 13 years
and continue to be developed have just made it a
lot easier and a lot more sensible for us to practice
minimally invasive care."
Among the innovations that may prove particularly
beneficial to minimally invasive care are a number
of new and expanded uses of lasers, new bur designs
and a caries intervention and prevention system developed
in California called Caries Management By Risk Assessment
(CAMBRA). Of these developments, Kutsch says he's
most excited about CAMBRA.
Cambra
Already using the system in his own office, Kutsch
says, "I get to the cause of the disease, instead
of just treating the symptoms," he says. "When
you're focused on just treating the symptoms surgically,
which traditionally is what we've done in dentistry,
you never catch up. You never get ahead."
The byproduct of a consensus conference held in
April 2002 in California, CAMBRA allows dentists
to "get in at a much earlier stage of decay," says
John Featherstone, Ph.D., chair of the department
of preventive and restorative dental sciences at
the University of California, San Francisco School
of Dentistry.
Featherstone, who organized the conference, published
a consensus statement on CAMBRA in the March issue
of the Journal of the California Dental Association.
Characterized as a set of recommendations and guidelines
for practical caries intervention and prevention,
CAMBRA essentially involves a more involved patient
health history form specifically geared to help determine
a patient's risk of caries, a test to measure the
level of cariogenic bacteria in the patient's mouth
and a set of recommendations for caries control and
management.
According to the consensus statement, the diagnostic
screening process begins with the usual examination.
That is followed up with a series of questions from
the caries risk assessment form to obtain the maternal
dental history, the oral health of the entire family,
the socioeconomic status of the family and the frequency
of ingestion of fermentable carbohydrates. "High-fructose
corn syrup is the major sweetener in the United States," the
consensus statement notes. (Visit http://www.cdafoundation.org/journal/for
the form.
If indicated, the office then may need to measure
the level of bacteria in the patient's mouth. Currently,
there is only one such test available, says Featherstone.
That is the Ivoclar Vivadent Caries Risk Test (CRT),
which includes the bacteria two-in-one dip-slide
test that permits both lactobacilli counts in saliva
as well as mutans Streptococci counts in saliva or
plaque to be measured on the same slide. Though the
saliva sample can be gathered easily enough for the
test, results are not available for 48 hours.
Levels of mutans streptococci of 105 cfu/ml and
lactobacilli of 103 cfu/ml and above are considered
high risk.
Then, if indicated, the office may need to test
the patient for salivary dysfunction to help pinpoint
the cause of the cariogenic bacteria found in the
mouth or to learn why there's been a sudden increase
in carious lesions.
"If bacteria levels are low," says the
consensus statement, "any early carious lesions
detected may be treated and reversed by employing
topical fluoride treatments. If the bacteria levels
are high, an antibacterial agent is necessary, followed
by fluoride treatments."
Featherstone notes that chlorhexidine gluconate,
available via prescription only, is used twice daily
for a two-week period every two to three months.
For high-risk patients, this therapy continues for
about a year. Chlorhexidine, however, isn't as effective
against lactobacilli, so this is one area where new
innovations would be welcome, suggests Featherstone.
HealOzone from CurOzone U.S.A. Inc. may be one such
alternative available in this country within the
next five years. Though only available overseas now,
HealOzone uses ozone gas to treat carious lesions,
and it has been shown to effectively reverse both
fissure and cervical caries with no pain for the
patient. (See "Ozone lands overseas," in
related links below.)
Another alternative, though not thoroughly proven
yet, is povidone iodine. This can be applied in the
dental office and has been shown to reduce the levels
of lactobacilli as well as mutans Streptococci, says
Featherstone.
In his practice, Kutsch notes that he's experimenting
with Betadine® as an alternative to chlorhexidine. "As
long as the patient is not allergic to iodine, it
kills caries-causing bacteria on contact," he
reports. "So a one-minute rinse, based on preliminary
research, kills all bad bacteria for three to four
months.
"We had been using chlorhexidine twice a day
for six weeks, which requires a lot of patient compliance," explains
Kutsch. With Betadine, he adds, it's a one-minute
rinse in the dental office and the patient is set
for three months. "That gives me a three-month
window to begin managing the caries in the patient's
mouth."
Antibacterial treatment then is followed by topical
fluoride treatments to promote remineralization and
prevent demineralization. This includes fluoridated
drinking water, fluoridated toothpaste or gels, over-the-counter
fluoride rinses, as well as professionally applied
topical fluoride varnishes, foams, gels, acidulated
phosphate fluoride and stannous fluoride. Prescription,
high-concentration fluoride gels and toothpaste are
available for high-risk patients, especially in adults
for root caries.
While CAMBRA identifies three pathological factors
that may put a patient at high risk for caries, not
all three need be present, adds Featherstone, noting
that the entire CAMBRA process requires the dentist's
clinical judgment to determine a patient's level
of risk.
Young, who will be lecturing on CAMBRA at the fourth
Annual World Congress of Microdentistry in August
at the Sheraton Wall Centre in Vancouver, B.C., says
a caries risk assessment is simply weighing the bad
factors, such as cariogenic bacteria, poor dietary
habits and salivary dysfunction, against healthy
oral health indicators like normal salivary function
and a number of remineralization and protective treatment
options.
And as not everyone who has cariogenic bacteria
ends up with decay, says Young, the caries risk assessment
becomes a critical tool to help a dentist determine
what might be happening in a patient who suddenly
begins developing a number of carious lesions. Even
if the cariogenic bacteria levels have remain unchanged,
he adds, "obviously there are other things going
on.
"It's the balance in each individual that's
different that you have to assess before you start
drilling a tooth."
Featherstone, citing a case from the UCSF dental
clinic, explains how CAMBRA works in practice: A
woman in her 20s, attending college for a couple
of years—a very driven person—was referred
to the dental school clinic by her general dentist,
who was at a loss to understand why she was suddenly
having new decay when she hadn't apparently had any
decay in the past. She had one cavity and a number
of others just getting started. The clinic conducted
a caries risk assessment, beginning with the Ivoclar
Vivadent Caries Risk Test. The clinic discovered
that she had a very high level of all of the caries-producing
bacteria in her mouth.
Next, the clinic performed a saliva flow rate test.
When that turned out normal, the clinic then asked
the patient about her diet. "She was forever
snacking," says Featherstone. "So she had
two out of three caries risk factors."
Plus, while the patient had reasonable oral hygiene
habits, they weren't the best. "So we began
treating her by putting her on chlorhexidine for
two weeks to bring down the bacteria levels," Featherstone
says. Next came a high dose of fluoride gel for the
following few weeks. Then back to chlorhexidine for
another week, and then back on fluoride. Then the
clinic restored the one carious lesion while the
other early carious lesions had been remineralized
thanks to the fluoride treatments.
"We took care of her lesion, her bacteria are
down and her fluoride use is up," concludes
Featherstone. "And she's modified her diet and
she is under control."
While Featherstone isn't ready to proclaim CAMBRA
a new standard of care, he suggests that all dentists
should follow this protocol from an ethical standpoint.
Not only will the legal system drive that, he says,
but conserving as much healthy hard and soft tissue
as possible has always been the goal of dentistry.
And it is accepted that doing so generally is in
the best interest of the patient.
And at least one dental negligence attorney has
been successful in winning cases against dentists
who don't currently practice the caries risk assessment
and treatment process now formalized in CAMBRA. In
fact, periodontist and attorney Edwin Zinman of San
Francisco is emphatic that all dentists should practice
caries risk assessment, intervention and prevention
because "it was, is and will be the standard
of care."
SMARTPREP
Whereas CAMBRA could be viewed as non-invasive,
suggests Dr. Daniel W. Boston, associate professor
and chairman of the restorative dentistry department
at the Temple University School of Dentistry in Philadelphia,
dentists still need help practicing minimally invasive
care once the decision has been made to restore a
tooth. That's what led him to invent a polymer instrument
that reportedly is incapable of harming healthy dentin.
S.S. White Bur Inc.'s SMARTPREP Instruments, unveiled
at the Chicago midwinter meeting in February, are
designed to remove caries, but leave healthy dentin
intact. The single-use polymer instrument breaks
down when it comes in contact with healthy tooth
structure.
"I think minimally invasive dentistry is on
all dentists' minds these days, trying to minimize
removal of healthy tooth structure," says Boston. "Also,
there's an interest in knowing when do you have all
the caries out—not wanting to over-prepare
and not wanting to under-prepare."
Boston also developed S.S. White's Fissurotomy® burs,
which allow dentists to cut a smaller access to carious
lesions. "The bur is designed for the specific
task of opening fissures when indicated," he
notes. "Within the fissure, you don't have to
do a standardized preparation where you'd cut the
entire fissure away and make a large preparation
for an amalgam. You can treat every millimeter of
the fissure according to the pathology that's present."
CO2 Laser
Though not currently available, a CO2 laser developed
by UCSF's Featherstone is another selective caries
removal system capable of removing decay without
harming healthy tooth structure. The laser heats
up the caries within the tooth, vaporizes the decay
and then allows the tooth to resolidify, he explains.
When Featherstone first began working on the laser
in the early 1980s, the goal was to develop a laser
that could be used to prevent decay, "that we
could alter the composition of the mineral in the
teeth, particularly the enamel, and make it much
more resistant to acid.
"What the laser does is heat up the surface
of the enamel a few microns deep to about 1,000 degrees
Celcius for a period of about a microsecond, and
then it cools down until we hit it with another pulse," continues
Featherstone. "And we recently did a safety
study that showed that the amount of energy that
we're putting in does not detrimentally raise the
temperature in the pulp and doesn't damage the tooth.
"So if you get your conditions in the mouth
just right," he concludes, "you can heat
up the surface of the tooth so the next time acid
comes around it can't dissolve that." This would
be particularly helpful on occlusal surfaces, he
adds. "If we could go right to a particular
pit where there's some early decay, blast that with
a very fine laser beam at exactly the right wavelength
with exactly the right conditions, what that will
do is actually melt together the decayed mineral
and it will cause the decay to evaporate and come
out as a plume."
Expect to see this caries removal laser available
within five years. As a preventive tool, however,
more long-term research will be required, says Featherstone.
Calculus Laser
Another hard-tissue laser that could be available
within three to five years promises to remove calculus
but not healthy tooth structure by focusing on the
absorbency of calculus, explains Dr. Peter Rechmann,
also a professor at the UCSF dental school. There
is a natural difference between the absorbency of
bacteria and that of healthy tooth structure, he
says. "This new blue laser is exactly absorbed
by bacteria," reports Rechmann, "so only
bacteria will be ablated. As soon as bacteria and
calculus are gone, the ablation stops."
Though there is no feedback mechanism built into
the laser, Rechmann says a doctor will know the laser
has completely removed decay when the "tick,
tick, tick" of the ablation sound stops. "As
soon as the bacteria are gone," he says, "you
hear nothing anymore." Ablation also produces
bubbles from the microexplosions that occur when
the laser beam hits decay and vaporizes it. "So,
no bubbles and no sound, it's done. It's clean."
The laser, he adds, can be used to get into the
sulcus and clean it without removing healthy cementum.
So it could be used as a maintenance tool, suggests
Rechmann.
New Laser Uses
While the caries and calculus removal lasers are
not yet available, at least one existing hard-tissue
laser on the market recently received FDA approval
for apiceoctomies—the Waterlase® system
(Biolase Technology Inc.).
Expect more such approvals in the coming years,
suggests Dr. Eric S. Bornstein, of Natick, Mass.
Bornstein, who owns two dual wavelength lasers (Er:YAG/Co2)
and two 830nm diode lasers from OpusDent USA, uses
the erbium lasers to do full apiceoctomy procedures, "from
flap design to bone ablation to cutting off the root
tip."
In fact, he's been using erbium lasers to do bony
surgery for more than two years. "And with tremendous
success," adds Bornstein. "It's much less
invasive than using a high-speed bone bur and much
safer … than a large round bur spinning at
250,000 rpm. In two years of doing these procedures,
I have yet to have one mishap."
With the erbium laser, he says, bacteria in the
path of the beam are vaporized as you cut through
bone. That's much better than "putting a high-speed
instrument on the tissue and basically just spinning
the bacteria around."
Though lasers have yet to capture a wide audience
in dentistry, Bornstein suggests that could change
as dentistry adopts a more minimally invasive approach
to dentistry. Within five years, he says, "I
think lasers are going to be ubiquitous in dental
offices across America."
One of the obstacles to widespread use of lasers,
he adds, is the perceived educational curve. To pick
up a laser and use it effectively, Bornstein says,
dentists think "they suddenly have to get a
degree in quantum mechanics. And that isn't necessarily
the case. If you start with one laser, say a diode
soft-tissue laser, and you become comfortable with
it, then you can move up to another laser, like a
hard-tissue laser." Just don't jump in all at once, he suggests. Dentists
who have tried that "end up burning tissue or
not getting the reaction they were looking for [and
they] get frustrated. And sometimes they will put
these big expensive machines in the corner and not
use them." |
