Guided tissue regeneration case study of a periodontal intrabony defect, with a surgical re-entry and clinical evaluation after 5 years
by Giacomo Tarquini, DDS
In predisposed subjects, the formation
of a periodontal bacterial biofilm may
induce periodontitis, which involves
chronic inflammation affecting the hard
and soft periodontal tissues. Periodontitis
may cause periodontal ligament destruction,
alveolar bone resorption and, in the most
severe cases, the loss of the affected teeth.1
Loss of alveolar bone support, a characteristic
sign of periodontal disease, is generally
considered to represent the anatomical
sequela to the apical spread of periodontitis.
The persistence of deep pockets after
active periodontal therapy has been associated
with an increased probability
of tooth loss, owing to the possibility
that ecological niches (deep pockets
and furcation involvement) associated
with some osseous lesions may represent
site-specific risk factors or indicators for
disease progression.
The extent and severity of alveolar
bone loss are usually assessed by
periodontal probing and radiological
examination, namely periapical radiographs;
moreover, because of the limited ability to
provide a detailed view of three-dimensional
anatomical structures, cone-beam computed
tomography (CBCT) represents a substantial
aid in the diagnosis, treatment planning and
assessment of periodontal patients.
Principles of guided
tissue regeneration
When teeth have deep pockets and
reduced periodontal support, improvement
in short- and long-term outcomes may
be achieved by carrying out concomitant
regenerative interventions.
Because of differences in the healing
abilities of different periodontal tissues,
regeneration of the periodontium after
traditional access flap procedures is difficult
to obtain. One of the most important factors
that limit the achievement of a predictable
regeneration is in fact the downgrowth of
junctional epithelium along the denuded
root surface.
Guided tissue regeneration (GTR) therapy
involves the use of barrier membranes and
grafting bone substitutes to allow selective
repopulation from the periodontal ligament
and alveolar bone while excluding the gingival
corium cells that usually repopulate the
wound healing site first.
Many clinical studies and systematic
reviews (with meta-analyses) have shown
that the treatment of one-, two- and three-wall
intrabony defects with GTR reduces
periodontal probing depth and improves
clinical attachment loss when compared
with an open-flap debridement approach.
Prognostic factors
Prognostic factors in GTR may be
classified in four different categories:
patient-related, tooth-related, site-related
and surgery-related factors.2
Patient-related: Significant clinical
improvements can be expected only in
nonsmoker patients with optimal plaque
control and reduced levels of periodontal
contamination.
Tooth-related: Severe and uncontrolled
tooth mobility (Miller Grade II or higher)
may impair the regenerative outcomes.
Site-related: Defect morphology plays
a major role in healing after periodontal-regenerative
treatment of intrabony defects.
The depth of the intrabony component of
the defect influences the amount of clinical
attachment and bone gained, although it has been demonstrated that deep and
shallow defects have the same potential
for regeneration. In other words, after the
treatment of deep defects, we’d expect to
achieve linear amounts of attachment gain
that are larger in absolute value than those
obtained after the treatment of shallow
defects, but both deep and shallow defects
can express a regenerative potential up to
the complete resolution of the intrabony
component of the defect.
Another important morphological
characteristic of the defect is the width of
the intrabony component: the angle that
the bony wall of the defect forms with the
long axis of the tooth. Wider defects have
been associated with reduced amounts of
clinical attachment level and bone gain.
It has also been shown that the number
of residual bony walls is correlated with the
outcomes of various regenerative approaches,
but it should be noted that the number
of walls and the width of the defect are
influential when nonsupportive biomaterials
are used.
Nevertheless, the influence of defect
anatomy appears to be mitigated, to some
extent, when a more stable and long-lasting
combination of barrier membrane and bone
replacement material is applied.
As far as surgery-related factors, key
concept for successful regeneration includes:
- The presence of space for the
formation of the blood clot at the
interface between the flap and the
root surface, which can be provided
by the use of self-supporting
membranes and/or graft biomaterials.
- The stability of the blood clot.
(That’s why membranes should be
fixed with pins or titanium screws.)
- The soft-tissue protection of the
interdental area, to avoid surgical
wound dehiscence and thus bacterial
contamination of the underlying
membrane. Its incidence could be
greatly reduced with the use of access
flaps specifically designed to preserve
the interdental tissues, such as papilla
preservation techniques.
Surgical approach: Papilla preservation
techniques
Papilla preservation techniques were
developed to achieve and maintain primary
closure of the flap and to increase the ability to
create space for regeneration in the interdental
area. This approach is based on the elevation
of full-thickness buccal and lingual flaps,
followed by a buccal periosteal incision
to increase buccal flap mobility. Vertical
releasing incisions are traced when needed.
Flaps are generally coronally positioned
on top of barriers, grafts or combinations
and are sutured with a double-layer suturing
technique to provide stable interdental
closure.
The modified papilla preservation
technique (MPPT) can be successfully
applied in the anterior and premolar region
when the interdental space width is ≥2 mm
at the most coronal portion of the papilla.3
When interdental sites are narrower
(<2 mm) or when we are in molar region,
a different papilla preservation procedure
has been proposed: the simplified papilla
preservation flap (SPPF).4
Materials for
regenerative surgery
Regarding materials and products,
three different regenerative concepts have
been explored: barrier membranes, grafts
and wound-healing modifiers, and many
combinations of those.
Early studies involved nonresorbable
membranes—especially expanded polytetrafluoroethylene
(ePTFE) barrier membranes—
but the need for a second surgical procedure
to remove them, the consequent increase
in morbidity and the recognized problems
associated with protection of the regenerated
tissue following membrane removal have
directed most clinicians toward the use
of bioabsorbable membranes derived from
native or linked collagen fibers, pericardium
or poly-D,L-lactide-coglycolide (PLGA).
Because a considerable number of controlled,
randomized clinical trials comparing
outcomes after application of bioabsorbable and nonresorbable membranes failed to
demonstrate clinically significant differences,
the use of a bone substitute covered with a
resorbable membrane shall be considered
capable of allowing for a satisfactory periodontal
regeneration.5
Another important issue concerns
debridement of intrabony defects and root
surface decontamination. Owing to the
acoustic microstreaming and the cavitation
effect, dedicated ultrasonic inserts demonstrated
their efficacy in GTR procedures.6
Moreover, their specific shape is particularly
useful when treating deep and narrow
intrabony defects.7
Clinical case
After clinical examination and intraoral
radiographic assessment (Figs. 1–3),
surgery was performed as follows.
Antibiotic prophylaxis before surgery,
then every 12 hours for six days, was initiated
and the patient was instructed to rinse with
0.2% of chlorhexidine, to be continued for
two weeks after surgery. In addition, 220 mg
of naproxen sodium was administered
one hour before surgery, then twice a day
for three days.
Fig. 1: Presurgical defect sounding.
Fig. 2: Presurgical periodontal chart.
Fig. 3: Presurgical periapical radiograph.
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 defect was achieved using the modified
papilla preservation technique (Fig. 4).
The reactive granulomatous tissue within
the intrabony defect was debrided using
Gracey curettes (Fig. 5) and root
decontamination was carried out using
ultrasonic inserts (Fig. 6).
Fig. 4: Access flap according to MPPT surgical protocol.
Fig.5: Reactive tissue debridement with Gracey curettes.
Fig. 6: Root surface decontamination by the means
of ultrasonic inserts.
The intrabony component of the defect
(Fig. 7) was measured by means of a
15-mm periodontal probe (Fig. 8). The
defect was grafted with a bone substitute and
a 25-by-20-by-0.2-mm collagen membrane
was trimmed using sterile scissors, positioned
to cover the defect (Fig. 9) then
stabilized with titanium pins (Fig. 10).
Fig.7: Clinical aspect of the intrabony defect.
Fig.8: Intrabony component of the defect,
measured with a 15mm periodontal probe.
Fig.9: Resorbable barrier membrane and bone
substitute positioned over the bone defect.
Fig.10: Resorbable barrier membrane
secured with a titanium pin.
Full flap closure was achieved, and the
flaps were sutured using 5-0 nonresorbable
PTFE sutures (Fig. 11).
After suture removal, the patient was
followed up with every three months until
healing had occurred with no complications
or adverse events (Fig. 12).
Fig. 11: Flap is sutured according to MPPT protocol.
Fig. 12: Soft tissue healing.
Results
At the final follow-up, the CAL gain
was 9 mm and the residual PPD was 3 mm
(Fig. 13).
Starting from the 12-month check-up,
the CAL was not significantly different
from that at the previous visit. Additionally,
starting from the 24-month check-up, the
mean PPD was not significantly different
from that at the previous visit, indicating
that bone resorption was absent or limited
from that time onward; indeed, as shown
in periapical radiograph, the bone defect
was completely filled (Fig. 14).
Fig. 13: Postsurgical periodontal chart at 24-month follow-up.
Fig. 14: Postsurgical periapical radiograph
at 24-month follow-up.
At five years from the surgery, a surgical
reentry independent of the intrabony defect
previously treated was necessary, due to a
second GBR procedure next to the intrabony
defect reported here. Such condition required
a flap opening involving the intrabony defect
and thus allowing its clinical evaluation.
Surgical reentry allowed a clinical
evaluation of the previous surgical clinical
inspection and revealed that the intrabony
defect was repaired and the aspect was that
of newly formed mature bone of the patient
(Figs. 15 and 16).
Fig. 15: Surgical reentry procedure after 5 years (buccal aspect).
Fig.16: Surgical reentry procedure after 5 years
(occlusal aspect).
Conclusions
Many clinical studies and systematic
reviews (with meta analyses) have shown
that the treatment of periodontal defects
by grafting bone substitutes in combination
with GTR membranes reduces PPD and
improves CAL; furthermore, they showed
that the CAL gain was maintained over
time thus providing a high percentage of
long-term success.
In this specific case, a surgical reentry
was performed at a 5-year follow-up and
clinically confirmed the reestablishment
of the lost periodontal attachment and the
complete filling of the bone defect.
Similar clinical feedback is rare in literature
and represents important clinical
evidence of the success of the intrabony
defect healing.8
References
1. Tarquini G. Treatment of intrabony defects using
equine-derived bone granules and collagen membranes:
A retrospective study with 13-year follow-up. Journal
of Contemporary Dental Practice, Volume 21: Issue 9
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2. Cortellini P, Tonetti M. Focus on intrabony defects: guided
tissue regeneration. Periodontology 2000, Vol. 22, 2000,
104–132
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preservation technique with bioresorbable barrier membranes
in the treatment of intrabony defects. Case reports. Int J
Periodontics Restorative Dent 1996;16:547–559.
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papilla preservation flap. A novel surgical approach for the
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6. Tarquini G. Ultrasounds in periodontal surgery: clinical
effects. Cap. 1. In: Tarquini G. “Tecniche di chirurgia
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8. L Florès-de-Jacoby 1, A Zimmermann, L Tsalikis Experiences
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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.