A new single-bottle solution from Brasseler could eliminate the need to juggle bottles and syringes
by Dr. Allen Ali Nasseh
It’s been drilled into our heads by most of our mentors
that the cleaning component of the endodontic triad
of cleaning, shaping and obturation is the most
important determinant of clinical success in root
canal therapy. However, we tend to spend more time
and effort evaluating the latest instrumentation method or
finding ways to enhance the final look of our radiographs
by incorporating more radio-opaque cements into our
clinical armamentarium instead of focusing on improving
our irrigation protocol and, by proxy, our outcomes.
To make things worse, when we finally decide to
focus on irrigation, we find that we either are facing a
complicated irrigation protocol shared by many experts
on the field or are told that we need expensive laser-based
or sound-based devices to facilitate the irrigation process,
forcing us to either increase our fees or face a greater
overhead. How can we simplify our irrigation protocol
without expensive gadgets and complicated initial and
final irrigation protocols?
Before we set out to simplify our irrigation protocol,
it would be worthwhile to review the important concepts
that apply to effective irrigation, which chemicals are
commonly used and the objective for their use. I’ll briefly
discuss some of the physical and chemical parameters in
irrigation process and irrigation solutions and potential
interactions between the reagents commonly used.
Physical parameters
and limitations
The root canal anatomy can be intricate, with many
curves, fins and anastomoses. And while the coronal pulp
chamber and the coronal root have many dentinal tubules
that can act as potential sites of microbial penetration, these
spaces constitute a very small volume. The root canal has
a volume of 20–40 microliters,1 with an average of about
0.025 cubic centimeters (cc), equal to the volume of about
half a drop of water. Therefore, each cc of irrigation solution
will displace 20–40 root canal volumes. This is important
considering the fact that volume is a key component of
effective irrigation. However, we don’t know exactly
how much volume replacement is enough for effectively
cleaning and whether the chemistry of chemicals used can
catalyze this event. We do know that heat increases the
kinetic energy of the solution and will therefore catalyze
the rate of reaction.2,3
Beyond the volume, the delivery of the solutions into
the root canal is also important. Positive-pressure irrigation
is when the solution is pushed through the syringe with
the use of a needle deep in the root canal. Needles with
different tip designs distribute the irrigants differently.
Closed-ended, side-vented needles are currently the safest
needles for use because they reduce the risk of irrigation
extrusion from inside the canal. However, while these
needles must be placed deep in the canal to be effective,
it’s important to use the thinnest needle available and make
sure it’s not binding in the canal during irrigation. To help
reduce the odds of accidental extrusion, negative-pressure
systems were recently developed where the vacuum force
is moved to the apex with the aid of a thin needle/cannula
and the irrigation solution is deposited coronally in the
access opening. This method helps reduce the odds of
solution extrusion. The downside of negative pressure,
however, is the ergonomics of the system and the chance
of the small suction needle getting blocked prematurely
Fig. 1:Positive pressure using thick needles does not allow
the needle to go deep in the canal. Furthermore, it can lock
the needle in the thinner portions of the canal, causing a
hypochlorite extrusion.
Fig. 2:This is why the thinnest available needles (Size 31
gauge) should be used to allow deeper insertion without
needle binding, allowing the solution to fl ow back up coronally
instead of apically.
Chemical parameters and limitations
Simply put, most irrigation solutions are solutions
based on acids, bases, disinfectants or lubricants.
The main goal of irrigation is the removal of the
macrodebris generated during instrumentation and
use the aforementioned chemicals to achieve the three
main objectives of irrigation:
- Dissolve organic tissue—pulp, organic portion
of dentinal chips, collagen, smear layer, etc.—
from inside the root canal.
- Gently dissolve inorganic tissue—smear layer,
dentinal chips and calcifications— inside the
root canal space.
- Disinfect surfaces left behind by destroying
all forms of established biofilms inside the
root canal.
To date, this has been achieved with a concentration
of 1%–6% sodium hypochlorite solution (NaClO), with
lower concentrations used for disinfection only and
higher concentrations for additional tissue dissolution. In
addition, we’ve used a 17% solution of ethylenediamide
tetraacetic acid (EDTA) to remove loose inorganic
components inside the root canal. Additional lubricants
such as RC Prep (Premier Dental) and surfactants to
reduce surface tension and aid in solution penetration
inside dentinal tubules have also been used for additional
benefits, but aren’t essential to the irrigation process.
One challenge: NaClO and EDTA can’t be mixed
because they neutralize and hydrolyze each other within
a few minutes after mixing.4 This is why operators
have to use two separate syringes for each solution.
If chlorhexidine (CHX) is also used, an additional water
rinse is required between NaClO and CHX to avoid
a toxic precipitate.
Generally, the NaClO and EDTA solutions are used
intermittently throughout the process, with additional
protocols of EDTA at the end to remove the smear layer.
This is because of an additional chemical limitation
when using NaClO in teeth: It is not only buffered by
EDTA but also buffered and neutralized very quickly
upon contact with dentin and dentinal chips. Therefore,
the use of EDTA interchangeably throughout the process
has been theorized to help dissolve the dentinal chips
and help reduce the rate of NaClO deactivation. But
because they cannot be mixed together, they are used
in different syringes interchangeably. Lubricants enter
the scene as well as per operator’s discretion.
These chemical interactions and buffering limitations
have created a long, laborsome process of using multiple
syringes with multiple needles throughout the process.
Are we forced to work through this multiple syringe
system and accept this complexity?
A better solution?
While the use of these three basic solutions in
alternate syringes has become second nature to most of
us, chemists from a few companies over the past decade
have been working to develop a series of chelating
chemicals that can withstand the harsh and corrosive
reaction between NaClO and EDTA by focusing on
replacing the EDTA component of irrigation with a series
of substitute chelating agents that are less neutralizing
to NaClO.
It’s important to note that this scientific effort
was made to replace EDTA rather than NaClO in
this process because NaClO is considered the gold
standard irrigant in the endodontic therapy, primarily
because of its simultaneous action on organic tissue
dissolution while being an effective disinfectant. As a
result, instead of reinventing the wheel by developing
a new disinfectant and a new organic solvent, which
would have required prospective long-term studies to
validate their efficacy, NaClO was used as the base for
a new solution that contains a mix of 11 different gentle
chelators that exhibit resistance to NaClO and do not
buffer NaClO as quickly as EDTA.
Furthermore, a number of saponification agents and
lubricants were added to the mix, so the final cocktail of
solutions can address all three requirements of irrigation
and potentially more all in one solution. The resulting
irrigation solution is Triton (Brasseler). The delivery of
the irrigants in one bottle is possible through its unique
dual-barrel delivery system, in which 8% NaClO is
mixed 1:1 with a solution of chelating agents, lubricants,
surfactants and detergents. As a result, the final solution
drawn into the syringe is a 4% solution of NaClO with
all the additional ingredients in it.
The solution is stable for three to five hours after
mixing/drawing from the bottle, beyond which the
NaClO concentration is considered too low for its
intended use, so it is drawn/mixed to use per patient.
Each bottle yields a total 480ml of solution, which at
6ml/cc per case (average use) would allow for about
80 cases. The unmixed solution in the bottle has a
shelf life of one year on the bench top and two years
in the refrigerator.
Independent scientific studies have been performed
by universities around the world and the studies are on
the publication path at the time this article was written.
The results of these studies show excellent disinfection
qualities, as expected from a NaClO-based solution.
Further synergistic effect is possible, because simultaneous
application of chelation during disinfection can potentially
have a catalytic effect on both processes. This and other
results have to be seen. Being a hypochlorite solution,
Triton should be kept inside the tooth and the same
care with any NaClO irrigation should be applied here.
While the future of this particular product is
bright and it may be shown to improve the irrigation/
disinfection process, one thing is certain: The move
from multiple syringes and a complicated irrigation
protocol to a simpler irrigation protocol where a single
syringe can be used from the beginning to the end of
the procedure without any sequencing needs allows for
a more efficient irrigation protocol for most clinicians.
Also, by maintaining 4% sodium hypochlorite
as the main active ingredient in Triton, we can apply
through precedent the existing body of literature and
long-term clinical experience about the efficacy of this
solution for disinfection. All the additional benefits and
its potential synergy will be a bonus to the clinician.
Reference
1. Cardoso, F.G. da R., Martinho, F.C., Ferreira, N de S., do Prado, R.F.,
Manhães-Júnior, L.R.C., Rocco, M.A., and Valera, M.C. “Correlation Between
Volume of Root Canal, Cultivable Bacteria, Bacterial Complexes and Endotoxins
in Primary Infection.” Braz Dent J 30 (2); March-April 2019. https://doi.
org/10.1590/0103-6440201902239
2. Basrani, B. and Haapasalo, M. “Update on Endodontic Irrigating Solutions.”
Endod Topics, 27: 74–102 (2012). https://doi.org/10.1111/etp.12031
3. Haapasalo, M., Shen, Y., Wang, Z., et al. “Irrigation in Endodontics.” Br Dent
J 216, 299–303 (2014). https://doi.org/10.1038/sj.bdj.2014.204
4. Zehnder, M. “Root Canal Irrigants,” Journal of Endodontics, Vol. 32, Issue 5,
389–398 (2016), https://doi.org/10.1016/j.joen.2005.09.014.
Dr. Allen Ali Nasseh received his
dental degree from Northwestern
University Dental School and
completed his postdoctoral
endodontic training at Harvard
School of Dental Medicine, where he
also earned a master’s degree in the
area of bone physiology. He has been
a clinical instructor in the postdoctoral endo department
at Harvard School of Dental Medicine since 1994.
Nasseh is the current president and CEO of Real World
Endo and the editor of the Harvard Dental Bulletin and
several other dental journals and periodicals. He has a solo
private endodontic practice and an endodontic educational
institute in downtown Boston.