A novel, promising approach decontaminates
surfaces and reduces inflammation of soft tissue
by Giacomo Tarquini, DDS
Peri-implantitis is defined as inflammation of peri-implant soft
tissues, associated with a progressive loss of supporting bone that
occurs after the establishment of osseointegration.1
With regard to the therapy, which can be addressed through a
resective or a regenerative approach according to the local anatomy, the
most debated issue has been related to implant surface decontamination.
Despite several protocols that have been proposed—mostly based on
antimicrobial agents, power-driven tools, air abrasives, laser or manual
instruments—no single method of surface decontamination has been
found to be superior.2
Among these options, ultrasonic cavitation (the formation of vapor
phase bubbles within a liquid, usually because of rapid changes in localized
pressure) has been demonstrated to be highly effective in removing
biofilms from a substrate at the microscopic level, with no damage to
the underlying surface. Cavitation bubbles are in fact capable of yielding
microstreaming, shock waves, high-speed jets and liquid heating, which
cause biofilm disruption from both polished and micro-roughened
surfaces.3 Several authors have showed the potential for this technique
as a new method of bone defect debridement as well as dental implant
decontamination.4,5
The aim of this article is to describe the
biologic rationale of ultrasonic cavitation in
biofilm removal and to show a clinical case of
peri-implantitis treated by means of a novel
ultrasonic cavitation device (Piezoclean by
Dr. Giacomo Tarquini) associated with a
guided bone regeneration (GBR) procedure.
State-of-the-art
decontamination
Modifications in the micro- and nanotopography
of dental implants have been
proposed to increase bone-to-implant contact
(BIC), but on the other hand, initial biofilm
formation on roughened surfaces may be
promoted when implant threads are exposed
to the oral cavity.6
Biofilm removal from dental implants
may be quite difficult, and decontamination
protocols used to date, such as antimicrobial
agents, power-driven tools, or laser or
manual instruments, have showed limited
success: Treated implants actually present a
remaining contaminated area that may affect
cell adhesion and proliferation. Moreover,
some of these methods can damage the
micro-roughened surface.7,8 Therefore,
research is being undertaken into novel
methods of biofilm disruption.9,10
A more recently studied protocol involves
using cavitation occurring in the cooling
water around ultrasonic scaler tips to allow
a contact-free approach: By conveying the
cooling liquid around the exposed part of the
implant and making sure it cavitates, every
crevice of its surface (such as macro- and
microscopically irregularities) as well as the
connection screw space can be reached. As
a result, a complete biofilm disruption is
achievable without modifying the implant
surface, unlike what happens with other
decontamination protocols.11
Why is complete decontamination
so important?
It has been demonstrated that the chance
to get a new osseointegration process (also
known as reosseointegration) of previously
infected implants is extremely limited
around polished, physicochemically altered
and/or incompletely detoxified surfaces
while, on the contrary, it occurs far more
predictably around properly decontaminated
micro-roughened surfaces.12–15
In light of this, a complete and predictable
decontamination is a prerequisite to achieve
the reosseointegration of treated implants.
The absence of any measurable changes to the
titanium surface and the lack of an organic
smear layer creates the ideal environment for
osteoblast-like cell adhesion and proliferation,
thus allowing for potential new osseointegration,
which is in turn the ultimate goal of
regenerative therapy.16,17
How is it performed?
From a practical point of view, the
main challenge with ultrasonic cavitation
is to succeed in creating a confined space
around the exposed part of an implant
where the cooling liquid would pool and
change at low flow rates; during clinical
use, the ultrasonic scaler operates in air,
with cooling water flowing around the tip,
and it’s hard to imagine the establishment
of a truly effective cavitation inside this
water mist. Therefore, it would be useful
to have the ultrasonic tip fully immersed
in a water flow.18 In this regard, the use of
the Piezoclean ultrasonic cavitation device
turned out to be particularly useful.
The device is made of two parts (Fig. 1):
- An ultrasonic tip (which must
be connected to a piezoelectric
handpiece), provided with three
microholes to promote the circulation
of cooling water (ES004E, Esacrom,
Imola, Italy).
- A medical-grade silicone cavitation
chamber specifically designed to pool
the cooling water and perfectly fit
any shape of crestal bone (Piezoclean,
Esacrom).
Fig. 1
The device is assembled by inserting
the cavitation chamber onto the ultrasonic
tip (Fig. 2).
Fig. 2
After removing all the prosthetic components,
the cavitation chamber is placed
around the exposed part of the implant and
the piezoelectric device is then activated
(Fig. 3); this creates a secluded space where
the cooling liquid cavitates without being
dispersed. Thanks to the presence of the
medical-grade silicone cavitation chamber,
the cooling liquid is locally concentrated
around the exposed portion of the implant,
thus allowing for a complete decontamination
of those areas (e.g., implant threads, surface
microgrooves and connecting screw housing)
that would otherwise be inaccessible to the
traditional tools such as Gracey’s curettes,
power-driven brushes or glycine airflow.
Fig. 3
The optimal running time for a complete biofilm disruption is about three minutes; it
is recommended to take a short break every
60 seconds to prevent overheating of the
cooling liquid. (The temperature was found
to increase by about 10 degrees Celsius after
operating for three consecutive minutes.19)
Clinical case
A 55-year-old patient with no medical
history was referred for suspected periimplantitis
affecting the implant on #11.
Peri-implant probing and preoperative
periapical X-ray examination confirmed
the diagnosis of peri-implantitis, suggesting
the presence of a large bone defect on the
buccal side (Figs. 4 and 5).
Because of its limited ability to prove
a detailed view of the three-dimensional
anatomical structures, periapical X-ray
examination may not provide full information
about important parameters such
as alveolar bone thickness, anatomy, size,
extension and location of bone defects. To
overcome this limitation, clinicians must
cross-correlate the data from X-ray examination
and peri-implant probing (Fig. 6).
Clinical parameters such as mBI, mPlI,
PD and implant mobility (IM) were registered
at baseline.
After removing both fixed partial prosthesis
and abutments, two cover screws were
placed on implants #11 and #13 to ensure a
spontaneous soft tissue regrowth, allowing
for a submerged surgical procedure (which
is scheduled after two weeks).
Surgery was performed as follows:
Antibiotic prophylaxis with 2 g amoxicillin/clavulanic acid (Augmentin) one hour
before surgery, and then every 12 hours for
six days. Patient was also advised to rinse
mouth with 0.2% chlorhexidine for two
weeks after surgery. In addition, 100 mg
of nimesulide was administered one hour
before the surgery, then twice a day for
three days.
The surgical area was anesthetized using
40 mg/mL of articaine hydrochloride with
epinephrine 1:100,000.
According to the local anatomy, access
to the peri-implant defect is achieved using
a trapezoidal full-thickness flap delimited by
two slightly divergent vertical incisions; the
crestal incision is always carried out within
the keratinized tissue (Fig. 7).
After flap elevation, a large peri-implant
defect with the presence of nonintegrated
biomaterial granules, perhaps remaining
from a previous surgical procedure, was
detected (Fig. 8). Accurate debridement of
the granules embedded in reactive tissue
was carried out by means of a dedicated
ultrasonic tip (Fig. 9).
Horizontal bone thickness (HBT) and
vertical bone defect (VBD) around the
exposed part of the implant were measured
at the baseline with a periodontal probe,
then the cover screw was removed to decontaminate
both outer and inner surface of
the implant.
The ultrasonic cavitation device was
placed onto the exposed part of the implant—there’s no need to create a tight seal between
cavitation chamber and crestal bone—and
the device was then activated (Fig. 10). A
non-contact approach (without the metal
tip contacting the implant) is advisable to
avoid damaging the implant.
At the end of the decontamination
process, a new sterile cover screw was positioned
(Fig. 11).
Because the bone defect has a space-keeping
morphology, a PLA/PLGA resorbable
barrier membrane (Activioss, Lyon, France)
was positioned to exclude certain cell types,
such as rapidly proliferating epithelium
and connective tissue, thus promoting the
growth of slower-growing cells capable of
forming bone (Fig. 12).
Alloplastic biomaterial (Activioss) was
grafted into the defect to support the membrane
and promote blood clot stabilization
(Fig. 13); the membrane was folded on
the graft, then stabilized with Ustomed
titanium pins (Fig. 14). A tension-free flap
closure was achieved, then sutured using
5-0 nonresorbable PTFE sutures (Fig. 15).
Suture were removed after 14 days and
the patient was followed up with every three
months until healing had occurred with no
complications or adverse events. After six
months of undisturbed healing (Fig. 16), a
surgical reentry procedure was planned. At
the moment of flap elevation, peri-implant
bone defect appeared completely filled and
previously exposed implant threads are fully
covered with newly formed tissue (Fig. 17).
Fig. 16
Fig. 17
HBT and VBD around the implant
were measured with a periodontal probe,
along with periapical X-ray examination
and intraoperative evaluation of the new
regenerated tissue density using a periodontal
probe at a pressure of approximatively 0.25 N
to confirm a satisfactory quality and quantity
of this tissue (Fig. 18). Healing abutments were
then placed over the implants (Fig. 19).
Fig. 18
Fig. 19
To increase the keratinized tissue width,
the flap was apically positioned and sutured
with crossed horizontal mattress sutures
(Fig. 20). Sutures were removed
after seven days and the patient was sent back to the referring dentist. Supragingival
professional tooth cleaning was performed
every week for 60 days and the patient was
followed up with every three months until
healing had occurred with no complications
or adverse events.
Fig. 20
Clinical parameters such as mBI, mPlI,
PD and implant mobility (IM) were registered
at the 12-month follow-up visit, confirming
a state of peri-implant health (Fig. 21).
Fig. 21
The results:
- Clinical parameters before and after
treatment are summarized in Table 1.
- The mBI, mPlI and PD values at
the follow-up visit were significantly
lower than those from baseline.
- IM remained unchanged.
- HBT was significantly higher at
re-entry surgery, compared with
baseline.
- VBD was significantly lower at
re-entry surgery, compared with
baseline.
The data indicates that after one year, the
treated implant could be considered healthy.
Conclusions
Bacterial biofilm accumulation around
dental implants is a significant problem,
leading to peri-implant diseases and implant
failure.
The most critical issue in regenerative
therapy of peri-implant vertical bone defects
is related to the possibility of obtaining a
predictable implant surface decontamination.
Though several methods have been described
so far, the literature does not clearly indicate
superiority of a specific decontamination
protocol. Cavitation occurring in the cooling
water around a dedicated ultrasonic tip can
be used as a novel solution to disrupt bacterial
biofilm without any surface damage.
Although clinical results with the
Piezoclean device are very promising, more
randomized, controlled clinical trials as well
as histological confirmation are needed to
corroborate the current preliminary data.
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Giacomo Tarquini, DDS, graduated with honors in dentistry
and dental prosthetics from the Sapienza University of
Rome in 1994, and has been practicing dentistry for about 25
years. Today he practices in Rome with
particular interest in the disciplines of periodontology and
implantology. He is also a consultant, professor, tutor and
lecturer for a variety of dental specialties. Along with various
articles, Tarquini is the author of the textbook “Techniques of
Periodontal Surgery: from Diagnosis to Therapy.”