Air polishing was first introduced to the North American
dental profession in the 1970s as an effective means of quickly
and easily removing extrinsic stains and soft debris from tooth
surfaces. Despite scientific evidence showing it to be an effective
and efficient means of plaque and stain removal, being at least
three times faster than rubber cup polishing,
it hasn't been widely accepted. This is likely
due to the fact that dental hygiene programs
don't routinely incorporate air polishing into
the curriculum, preferring instead to focus
on rubber cup polishing. Opposition often
points to the mess of aerosolized sodium
bicarbonate coating everything in the operatory,
Air polishing research has taken an interesting
turn, focusing more recently on subgingival
biofilm removal to control disease,
rather than stain removal for aesthetic reasons.
To do this, a new powder was needed
that was significantly less abrasive than
sodium bicarbonate yet effective for biofilm removal. Glycine
powder is 80 percent less abrasive, safe on oral tissues and root
surfaces, effective for biofilm removal, and comfortable for the
patient. One of the leaders in this research endeavor is Dr.
Thomas Flemmig, currently a professor at the University of
Washington in Seattle. His work focuses on the subgingival
effects of glycine air polishing as well as the economic and clinical
practice implications. I recently had the pleasure of speaking
with Dr. Flemmig on this subject.
What peaked your interest in air polishing?
Flemmig: Several years ago I read a research abstract about
how air polishing with sodium bicarbonate reduced subgingival
biofilms in periodontal pockets. At the time, conventional wisdom
suggested that sodium bicarbonate was so abrasive that it
caused root surface abrasion and traumatized
gingival tissues. What we needed was a
powder that was less abrasive than sodium
bicarbonate and less harmful to the tissue yet
still removed biofilm. With that as our goal,
we looked into other powders, testing many
types and finding glycine powder to be 80
percent less abrasive than sodium bicarbonate
and safe for the gingival tissues. We
tested the glycine powder in an air polishing
unit with a standard, supragingival nozzle
and found it effectively removed both supra
and subgingival biofilm and was safe on root
surfaces. With a standard air polishing nozzle
the powder opened the sulcus to allow
the glycine powder to access the subgingival area to remove subgingival
biofilm (Fig. 1).
How did you test the glycine powder clinically?
Flemmig: In a series of clinical trials, we compared hand
instrumentation for subgingival biofilm removal and air polishing
with glycine powder. In the first two clinical trials we found
a significantly greater reduction in viable counts of subgingival
bacteria following glycine air polishing with a standard nozzle compared to hand instrumentation. No adverse effects were
experienced by the patients; in fact, the patients preferred the air
polishing to hand instrumentation. They found it to be more
gentle and comfortable.
How much time was spent air polishing each tooth?
Flemmig: Without any previous studies to guide the time
factor, we limited the time to five seconds per surface, which
equates to approximately nine minutes for a full dentition.
Recent data in our laboratory using a biofilm model indicated
that the time may be cut in half, but that still needs to be confirmed
in a clinical trial.
Many hygienists today use an ultrasonic power
scaler to deplaque sugbingival areas. How does this
compare to air polishing?
Flemmig: Air polishing is more effective
as the spray reaches much further than the
localized effect of an ultrasonic scaler. To effectively
remove subgingival biofilm, the ultrasonic
tip must be moved in an overlapping
fashion to touch the entire surface while the
air polisher spray easily reaches a broader area.
What about reaching into a deep periodontal
pocket rather than a healthy
Flemmig: With a standard nozzle, air polishing
with glycine powder has been shown to
be significantly more efficacious in removing
subgingival biofilm. EMS developed a subgingival nozzle to
reach deeper sites. The subgingival nozzle will reach pocket
depths up to 9mm (Fig. 2). In studies comparing the subgingival
nozzle to hand instruments, air polishing is consistently
more effective for biofilm removal.
How do you see air polishing with glycine powder
being used clinically today?
Flemmig: In a healthy mouth or one with mild gingivitis
with probing depths of 4mm, the standard nozzle with glycine
powder will be effective. In sites with deeper probing depths of
5mm or more, the subgingival nozzle with glycine powder will
be the instrument of choice. Air polishing is done first to remove
biofilm, the primary cause of both caries and periodontal disease.
When this is complete, calculus is easier to see and can be
removed with a power scaler or hand instruments.
Clinicians feel strongly that air polishing is too abrasive
and harmful to gingival tissues. Is the glycine
powder both effective and safe?
Flemmig: Yes, the glycine powder is effective for biofilm
removal and safe for gingival tissues and mucous membranes.
The low abrasive nature of glycine makes it safe for root surfaces
and oral mucous membranes. Rather than the stinging feeling of
air polishing with sodium bicarbonate, air polishing with
glycine powder feels as gentle as the water syringe spray on the
tissues. In fact, in a recently published clinical trial we have
directed the air polishing toward all the mucous membrane tissues
in the mouth with no damage or discomfort for patients.
Since much of the initial air polishing research took
place in Europe and glycine powder is easily available
there, has this approach been widely accepted?
Flemmig: Yes, reports suggest that supra- and subgingival
air polishing with glycine powder is widely accepted in Europe.
Do you anticipate North American hygienists will
embrace this approach to treatment
as glycine powder becomes more
widely available here?
Flemmig: We are creatures of habit and
the longer we are in practice, the harder it is to
change. The idea of replacing hand instrumentation
and prophy cup polishing with a
few minutes of air polishing with glycine powder
feels to clinicians as though their patient
care is put into question. Change comes
slowly when it turns a long-held approach
upside down. Traditionally the approach to
deplaquing subgingival areas has been to
insert instruments to the base of the pocket
and move the biofilm in an apical to coronal
direction. With subgingival air polishing with glycine powder,
the approach is coronal to apical.
Were you immediately convinced that air polishing
effectively removed subgingival biofilm?
Flemmig: I was skeptical at first, as I expect most clinicians
would be. After subgingival air polishing with glycine powder I
went back and checked with the probe and curettes to see if in
fact it was effective. My colleagues did the same. We weren't
ready to trust that this easier, faster approach was as good as our
old ways. When we were convinced it was effective and had
sound evidence from randomized controlled clinical trials, we
embraced the change in patient care as it led to better treatment
in less time with more comfortable patients. It takes time to
overcome skepticism of this new approach.
There is some worry that this technology will cause
emphysema by forcing air and powder into the tissues.
What are the statistics on this?
Flemmig: Based on the published cases with air emphysema
following glycine powder air polishing, the estimated incidence
of air emphysema is 1 in 666,666. That means that a hygienist would have to perform glycine powder air polishing on all of her
patients for 350 years to experience one emphysema case.
Furthermore, all of the three reported emphysema cases following
glycine powder air polishing resolved without treatment. It
has not been a serious issue.
Is there still a use for sodium bicarbonate air polishing
Flemmig: Yes, for supragingival areas with heavy stain,
sodium bicarbonate powder, which is much more abrasive than
glycine powder, is the powder of choice. For deplaquing, glycine
is the powder of choice because it is effective, safe and comfortable
for the patient.
I realize your research has been with glycine powder
for subgingival air polishing. Are there other powders
on the market for subgingival deplaquing?
Flemmig: There are several other
powders on the market for supragingival
air polishing: sodium bicarbonate, calcium
carbonate, aluminum trihydroxide
and calcium sodium phosphosilicate.
When selecting an air polishing powder
for subgingival deplaquing, it must be safe
on root surfaces and gingivae. Many of
these other powders are safe on enamel,
but too abrasive for root surfaces and gingivae.
Check abrasiveness before using
powders other than glycine subgingivally.
There are more than 30 publications
demonstrating that glycine powder is safe on a variety of restorative
materials, orthodontic brackets and root surfaces, and is
approximately five times less abrasive than sodium bicarbonate.
Besides being safe on root surfaces, you showed
that glycine powder is safe on all the oral tissues.
What prompted you to go beyond tooth surfaces for
Flemmig: The concept of full-mouth disinfection led
us to consider using the air polisher for all oral tissues:
tongue, buccal mucosae and palate. Bacteria are not limited
to supra- and subgingival tooth surfaces. The oral
cavity is a reservoir for recolonization. These tissues harbor
microflora contributing to new biofilm formation on
the teeth so it makes sense to include them in the
deplaquing approach and not limiting the air polishing to
just the teeth. Air polishing with glycine powder is faster
and much easier than profuse irrigation of the entire
mouth and oral tissues with chlorhexidine. Our goal with
these studies was a Proof of Principle that a low abrasive
air polishing approach to full-mouth disinfection was a
safe and effective option (Fig. 3). We were able to show in
a clinical trial that in patients with periodontitis, fullmouth
glycine air polishing significantly reduced the oral load
of Porphyromonas gingivalis compared to conventional treatment
using hand instruments. Our future research will be conducted
including this approach.
How do you see subgingival air polishing with glycine
powder impacting dental hygiene care in the future?
Flemmig: This new technology will make work easier and
faster for the RDH. It will reduce the amount of time and effort
needed to effectively deplaque the mouth. Prophylaxes accounts
for approximately one quarter of the national expenditures for
dental services. Here is an example of how adding this new technology
that takes less time will impact the business of dental
hygiene and the practice. For this I will use nationwide surveys by
the ADA to compare an average restorative dental practice with
three operatories and no hygienist to the same practice plus an
additional operatory for a dental hygienist seeing eight patients a
day or 1,900 prophylaxis or periodontal
maintenance visits per year. The takehome
income of the dentist employing an
RDH is 40 percent higher than the dentist
working alone. If the RDH now
incorporates subgingival air polishing
with glycine powder and saves 12 minutes
per appointment, allowing him/her to see
10 patients per day, the costs don't go up
but the profit doubles, providing a financial
benefit to both the hygienist and the
dentist. On the business side, this new
approach to patient care provides a benefit
for the patient of greater health and comfort, an easier appointment
for the hygienist and increased income for both the dentist
and the hygienist. Embracing new technology provides benefits
for all involved: the patient, the RDH and the dentist.
Thank you Dr. Flemmig for your focus on the future,
your exciting research findings and your dedication
to improving patient oral health.