This study evaluates the clinical results and compare reentry hard tissue measurements following regenerative surgery after strict implant decontamination peri-implantitis cases.

1. Peri-implantitis Treatment with a Regenerative
Approach:ClinicalOutcomes on Reentry
Presented by
Dr Jayashree Gupta
PG III Year
Benfenati S P, Roncati M, Galletti P, Tinti C. Int J Periodontics
Restorative Dent 2015;35:625–36

2. • Peri-implantitis has been characterized by an inflammatory
process around an implant, which includes both soft tissue
inflammation and progressive loss of supporting bone beyond
biological bone remodeling.
• Peri-implantitis, like periodontitis, occurs primarily as a result
of an overwhelming bacterial insult and subsequent host
immunity.
• Poor oral hygiene, history of periodontal disease, cigarette
smoking, and inadequate adherence to supportive
periodontal treatment have been identified as risk indicators

3. • Damage to the implant surface, corrosion, excess cement
retained in the peri-implant sulcus from cementretained fixed
implant–supported restorations, and occlusal overload are
positively associated with periimplant marginal bone loss;
however, poor oral hygiene is still a key causative factor in
peri-implantitis.
• Defect identification is crucial to reach a correct diagnosis,
which consequently can direct adequate treatment.
• Peri-implantitis should be treated without delay.
• Very little reliable evidence exists on the most effective
interventions, and to date, predictable treatment strategies
have yet to be established; consequently, its treatment has
become a challenge.
• Nonsurgical therapy has not been shown to be effective,
failing to predictably arrest the progression of peri-implantitis.

4. • Different surgical treatment modalities have been described
to manage periimplantitis, with different degrees of success
and, in some cases, promising results.
• Recently, a combined resective/regenerative surgical
approach has been advocated, with a limited clinical
application, for a marked exposure of the fixture surface,
unless combined with concomitant soft tissue augmentation.
• To limit objectionable esthetic effects, several bone
regenerative procedures have been proposed, but with
limited long-term follow-up to confirm their validity. confirm
their validity.

5. • More recently, however, a case series of 51 peri-implantitis
cases treated using a regenerative approach reported
extremely positive clinical results.
• The same authors, in another case series, performed reentry
flaps on implants with direct visual evidence of the defect fill
circumferentially, suggesting new bone formation.

6. AIM
The aimof this study was to evaluate the clinical
results andcomparereentryhard tissue
measurementsfollowing regenerativesurgery after
strictimplant decontamination.

7. MATERIALS AND METHOD
• Nine implants in six female patients, aged 48 to 63 years, who
presented with peri-implantitis defects with probing depths
(PDs) of more than 6 mm but no implant mobility, were
included in the study.
• Only one patient was a smoker (patient 1). The treatment
selected was a guided bone regeneration (GBR) approach.
Each patient received a detailed description of the procedure
as well as the study protocol, and written informed consent
was obtained.
• The reentry procedures were required as the abutment
connection phase for two-stage implant surgery,
approximately 12 months later, or for periodontal-restorative
treatment in an adjacent tooth, 22 months later.

8. • The surgical procedures were performed, following
personalized oral hygiene instructions and a nonsurgical
approach, after each patient had shown compliance.
• All patients had undergone screw-retained prosthetic
restorations, which were removed during the surgical
procedures and reinserted at the end of the treatment
(nonsubmerged approach) or at the end of the two-stage
procedure (submerged approach).
• Five of the six patients were treated with a submerged
approach, and only one underwent a nonsubmerged
approach. In two patients, resorbable membrane (Alloderm
GBR, BioHorizons) was used, and in the remaining four
patients, a nonresorbable expanded polytetrafluoroethylene
(e-PTFE) (Gore-Tex) was used.

9. • Of the six patients, two were treated with a nonsubmerged
(patient 1) and submerged approach (patient 2) and are
illustrative of the surgical protocol.
• The surgical regenerative technique was selected to avoid
membrane exposure, maximize space maintenance, protect
blood clotting, and stabilize wound healing.

10. Bone defect debridement
• The granulomatous tissue was thoroughly removed from the
periimplant defect with the aid of a high-speed handpiece,
using a long shank “Christmas tree” carbide bur, and a
Hirshfield file. It is strongly recommended to avoid touching
the implant surface.

11. Implant surface decontamination
The following steps describe the clinical approach for implant
surface decontamination:
• Ultrasonics with proper insert (ie, plastic-fused to metal)
(Piezon Master 700, EMS)
• Titanium curette (KLS Martin)
• Titanium toothbrush (Tigran PeriBrush, Dentalica)

12. Implant surface detoxification
The following steps describe the clinical approach for implant
surface detoxification:
• Air-powder abrasive ‐ Amino acid glycine for 1 minute (Air-
Flow Master, EMS) ‐ Sodium bicarbonate for 1 minute (Air-Flow
Master)
• Photodynamic therapy with 0.1% phenothiazine chloride, as a
photosensitizing agent for 10 seconds (HELBO, Bredent)
• Tetracycline application (50 mg/mL) for 3 minutes and rinsed
with saline solution for 30 seconds (Ambramicina, Sharper) No
implantoplasty was performed in any of the cases.

13. • Intrasurgical measurements and clinical assessments The
outcome variable for this study was bone defect depth.
Clinical data for the nine implants are summarized in Table 1.
• After debridement of the periimplant defects, the bone
measurements were recorded with a periodontal probe
(XP23/UNC 15, Hu-Friedy), using clinical assessment and
surgical photographs.
• The distance between the base of the implant shoulder and
the bottom of the defect was measured in millimeters.
• Bone changes were recorded at the same location, at the time
of initial surgery and at the time of reentry surgery

15. Postsurgical instructions and care
• No periodontal dressing was applied. Patients were instructed
to take 1 g of amoxicillin and clavulanic acid, twice a day for 6
days, and nonsteroidal analgesics, as needed.
• Proper home care was provided, recommending the daily
repeated use of a medicated gauze soaked in chlorhexidine
0.12% (Digital Brush, Enacare), especially for the first 3 weeks
after surgery.
• The patient had to wrap the gauze around the index finger
and use a sweeping motion in an apico-occlusal direction,
from oral mucosa to the implant/tooth surfaces, similar to the
roll brushing technique.

16. Clinical follow-up
• Patients were seen after 7 days and then weekly for the first
month, to monitor the healing phase.
• In all patients, surgery and the healing process proceeded
uneventfully, with minimal postoperative discomfort and
without complications.
• At the time of suture removal, after 14 days, the wound was
observed to have closed completely in all nine implants.
• Patients were placed on an individually tailored maintenance
care program.
• None of the surgical sites displayed signs of membrane
exposure or wound dehiscence during the entire healing
period.

17. Case reports
Patient 1
• A 55-year-old woman presented with a peri-implantitis lesion on a
machined implant (length, 18 mm; diameter, 3.75 mm) at the
maxillary right first premolar.
• The implant had been positioned in native bone 22 years earlier.
• Her medical history was unremarkable except for a moderate
smoking habit of 10 cigarettes per day since she was young, which
had reduced to 4 per day at the time of implant surgery.
• Her maintenance recall system was scheduled every 3 months,
alternating between the periodontist and a general practitioner.
Despite her maintenance care, after 18 years, the maxillary right
first premolar implant developed acute symptoms, characterized by
tenderness, swelling, and suppuration on light digital pressure.

18. • PDs ranged from 9 mm distofacially and 12 mm midfacially to
10 mm mesiofacially, with bone loss being slightly less than
50% of implant length.
• After rinsing with a chlorhexidine solution (0.12%) for 1
minute, the surgical area was anesthetized and the fixed
screw-retained restoration removed.
• Full-thickness flaps were elevated at the buccal and palatal
sites, exposing the peri-implant bone defect.
• The flap design was different from the buccal to palatal area
because of the absence of PD on the palatal sites.
• On the buccal aspect, where the bone defect was present, a
papilla preservation approach with an incision at the base of
the palatal papillae was selected so as not to jeopardize the
integrity of the interproximal soft tissues, the undesired
exposure of the regenerative materials during the prolonged
healing phase, and not least, to preserve esthetic outcomes.

19. • A palatal incision was made at the base of the adjacent
papillae.
• Facially, the full thickness flap was elevated intrasulcularly,
from the distal aspect of the maxillary second premolar to the
mesial aspect of the maxillary right canine.
• A vertical releasing incision was positioned on the distal
aspect of the second premolar.
• After flap elevation, periimplant bone defect debridement,
implant surface decontamination, and detoxification were
performed as previously described.

20. • The peri-implantitis–affected implant revealed a moderate to
advanced buccal dehiscence with a two-wall component at
both mesial and distal aspects and nine threads buccally (Fig
1).
• The bone defect measured midfacially, between the base of
the implant shoulder and the most coronal visible bone-to
implant contact, was 7 mm.

22. • A small cylindrical bur on a low speed
hand-piece was used to decorticate the
recipient bed, creating numerous bony
perforations to get access to the
underlying medullary cavities.
• A composite graft, hydrated
mineralized freeze-dried human
allograft (MinerOss, cancellous and
cortical bone, BioHorizons), combined
with autogenous bone chip graft
harvested from the same site using a
bone scraper, was positioned to
completely cover the exposed buccal
threads and fill the contiguous mesial
and distal bone defects (Fig 2).

23. • Hydrated acellular dermal matrix (AlloDerm GBR, BioHorizons)
was properly trimmed to completely cover and stabilize the
grafting materials, both of which were stabilized with a
titanium pin buccally, and with a simple 5-0 vicryl sling suture
(Ethicon, Johnson & Johnson) around the implant structure
(Fig 3).

24. • The periosteum at the base of the buccal flap was severed to
obtain a tension-free flap and to allow its coronal
repositioning, as needed, to fully cover the regenerative
materials and ensure transmucosal healing.
• Primary closure was attained with a combination of single
interrupted and horizontal internal mattress sutures (Fig 4).
• At the end of the procedure, the fixed screw-retained
restoration was repositioned in place, avoiding any type of
discomfort (functional or esthetic) for the patient.
• The postoperative phase and initial healing proceeded
without complications and with minimal postoperative
discomfort.
• The 12-month healing period was uneventful, with no
membrane and grafting materials becoming exposed.

26. • A reentry procedure was performed approximately 22 months
after treatment for peri-implantitis.
• The distal aspect of the adjacent tooth—the maxillary right
second premolar—needed a surgical crown-lengthening
procedure.
• Pocket depth, for the first premolar site implant, was reduced
to 3 mm on the distal aspect, 2 mm on the buccal aspect, and
4 mm on the mesial aspect.
• No bleeding on probing was present.

27. • The residual defect depth was 2 mm, which approximated 5
mm of bone fill.
• Fig 6 shows a periapical radiograph taken 22 months after
treatment.
• Exposure of this area revealed the following results: seven of
nine buccal threads were covered by bone like tissue that was
indistinguishable from the host bone and increased bone
thickness, even though the bone regeneration achieved was
not 100% (Fig 5).

29. Patient 2
• A 50-year-old woman presented with a peri-implantitis
lesion on a machined implant (length, 10 mm; diameter,
3.75 mm) as an intermediate abutment of a three unit
screw and cement-retained fixed implant restoration at the
mandibular right sextant.
• Three implants had been positioned in native bone
approximately 7 years previously during the rehabilitation
of her right mandible, at the second and first molars and
second premolar sites.
• The intermediate implant, at the first molar site, reported
progressive bone loss and increasing pocket depth 6 years
after loading, despite regular maintenance care.
• Her medical history was unremarkable.
• After a careful risk/benefit assessment and considering
different treatment options, it was decided to treat the
peri-implatitis lesion on the intermediate implant with a
GBR regenerative submerged approach.

30. • Although not functioning for 11 months, she could use the
same fixed prosthesis after completion of the treatment.
• The intermediate implant reported PDs ranging from 7 to 9
mm both buccally and lingually, with bleeding and bone
loss of approximately 50% of implant length.
• Furthermore, initial clinical and radiographic signs of
incipient peri-implantis were present on the distal aspect of
the implant at the mandibular right second premolar.
• The quality and quantity of keratinized tissue was
considered inadequate for a long-term prognosis.
• The cemented fixed screw retained restoration was
removed.
• Sulcular full-thickness flaps were elevated from the distal
aspect of the third molar to the mesial aspect of the first
premolar, at the buccal and lingual sites, thereby exposing
the peri-implant bone defect.

31. • Buccally, a “hockey stick” vertical releasing incision was placed
on the mesial aspect of the premolar, whereas lingually the
incision was extended at the base of the papillae of three
elements, mesial to the first premolar.
• During the intermediate implantation, a combined osseous
defect was detected, which was characterized by a more
pronounced horizontal component, compared with the
shallow mesial and distal infrabony components (Fig 7).
• Six threads were exposed on the lingual side and five threads
on the buccal side.
• Furthermore, the distal aspect of the mesial implant had two
exposed threads.
• It is the present authors’ opinion that such a clinical situation
must be managed with a submerged approach to
simultaneously treat horizontal and vertical components.

33. • This required removing the implant supported prosthesis with no
functional activity for the entire healing period. Implant surface
decontamination and detoxification were performed as previously
described.
• The bone defect measured midfacially, between the base of the
implant shoulder and the most coronal visible bone-to-implant
contact, was 7 mm.
• Numerous cortical bony perforations were created, and hydrated
AlloDerm GBR was properly trimmed to completely cover the bone
defects, stabilized with two titanium fixation screws on the buccal
side, and then displaced buccally for graft material positioning (Fig
8).
• A composite graft, hydrated mineralized freeze-dried human
allograft (MinerOss, cancellous and cortical bone, BioHorizons),
combined with autogenous bone chip graft, with the addition of a
small amount of tetracycline powder (ratio 5:1), was positioned to
completely cover the exposed buccal and lingual threads of the
bone defects (Fig 9).

35. • The periosteum at the base of both flaps was severed to
obtain a tension-free flap and to allow coronal repositioning
of the flaps, as needed, to fully cover the regenerative
materials.
• Primary closure was attained with a combination of single
interrupted and horizontal internal mattress sutures (Fig 10).
• This clinical submerged approach and a swelling, within
normal limits in the treated area, did not create functional or
esthetic issues for the patient.
• The postoperative phase was uneventful, with no membrane
or grafting materials becoming exposed (Fig 11).
• A reentry procedure was performed 11 months later, for an
abutment connection to replace the original fixed prosthesis
and to improve quality and quantity of the keratinized tissue
with mucogingival surgery.

37. • A buccal partial-thickness flap was elevated in the previously
treated sextant, providing an opportunity to assess the results
of the first surgical regenerative phase.
• Limited to the most coronal aspect of the intermediate
implant, the periosteum was displaced to allow a direct view
and post-treatment bone defect assessment.
• The lingual flap was minimally elevated with a full-thickness
approach on the most coronal aspect to allow bone fill
measurements.
• The combined defect, mainly characterized by a non
contained component, was completely eliminated, with the
previously exposed threads (Fig 12) being completely covered
and the lesion on the distal aspect of the mesial implant
resolved.

39. • Bone like tissue extending to the polished collar,
indistinguishable from the host contiguous bone, may suggest
that the graft materials were completely remodeled during
this 11-month healing period.
• Fig 13 shows a periapical radiograph taken at the reentry
procedure, after healing abutment positioning.

40. Results
• The intraoperative measurements reported a mean bone fill
value of 91.3%, ranging from 50% to 100%.
• The initial defect depths varied from 3 mm to 8 mm, with a
mean pre treatment defect depth of 5.44 mm.
• The mean post treatment defect depth was 0.44 mm, with a
mean bone gain of 4.88 mm.

41. Discussion
• The aim of this study was to evaluate the results of reentry
regenerative surgery in peri-implant defects, with a comparison of
the pre- and post-treatment assessments.
• In contrast to periodontitis, most peri implantitis defects occur
circumferentially around the implant.
• The bone response on the buccal and lingual aspects of the implant
can be qualitatively and quantitatively measured with similar
accuracy to that on the mesial and distal aspects, by means of bone
sounding and reentry procedures.
• The surgical reentry makes it possible to view and measure bone
fill, which is significant compared with tooth healing for the
different bone defect topographies.
• Furthermore, this approach gives the clinician the option to
improve hard tissue outcomes with further soft tissue treatment.

42. • Combination protocols for surgical treatment of peri-
implantitis have shown some positive clinical and radiographic
results, using clinical parameters, such as PD reduction,
clinical attachment level gain, gingival level changes, bone
level changes on periapical standard radiographs, or bone
sounding.
• In a recent study, reentry flaps performed on 12 implants in 5
patients with moderate to advanced peri-implantitis revealed
bone fill in all lesions ranging from 40% to 100% of the depth
of the presurgical defect, with hard tissue gains being stable
up to 8.5 years.
• This confirms the results of a previous study that measured
bone gain by changes in bone level on standardized
radiography or bone sounding.

43. • Similarly, in this reentry procedure study, though limited to
nine implants in six patients, the intraoperative
measurements reported a mean bone fill value of 91.3%, with
a range of 50% to 100%.
• The initial defect depths varied from 3 to 8 mm, with a mean
pretreatment defect depth of 5.44 mm. The mean post-
treatment defect depth was 0.44 mm, with a mean bone gain
of 4.88 mm. Only one patient (patient 1) with a single implant
was treated with a nonsubmerged approach, whereas the
remaining five patients were treated with a submerged
approach.
• The reentry evaluation of this single case using the
nonsubmerged approach revealed a bone fill of 71%, which
was considerably less than the 100% bone fill reported in the
other eight patients who received implants with the
submerged approach, with the exception of one case in which
the bone fill was only 50%.

44. • In the case of a nonsubmerged solution, the bony defect must
be filled with autogenous bone or a bone substitute and further
secured by connective tissue graft or resorbable membrane.
• Such a solution provides bone regeneration that is limited
mainly to the infrabony component, and to a lesser extent to
the suprabony component, with no functional and ethetic
adjustment.
• In the case of a submerged solution, the suprabony and
infrabony components must be treated by applying the
principle of GBR to vertical ridge augmentation, with a minor
variation of autogenous bone or bone substitute associated
with nonresorbable membranes or 6-month resorbable
membrane.
• Such a solution provides bone regeneration to both suprabony
and infrabony components but creates functional and esthetic
issues for the patient.

45. • A submerged environment requires the removal of the implant
supported prosthesis for the entire healing period, resulting in
no functional activity at the site.
• Three mandatory objectives are: (1) to create a sufficient space
beneath the membrane, (2) to exclude soft tissue ingrowth into
the defect region, and (3) to obtain primary, predictable soft
tissue closure at the surgical site for a prolonged and
uneventful healing period.
• No implantoplasty was performed, because full-thickness
tension-free flaps were displaced coronally to fully cover the
regenerative materials.
• Strict methods of implant surface decontamination and
detoxification were used before the regenerative materials
were placed, with minor changes made for all patients in this
study, regardless of implant surface characteristics.

46. • After membrane removal, following a 12-month healing
period, the clinical reentry reveals robust hard tissue formation
consistent with the radiographic finding.
• The space underneath the membrane is completely filled with
newly formed tissue that reaches the uppermost part of the
implant system.
• In a previous animal study, successful reosseointegration was
reported after proper implant detoxification using air abrasion.
• In this reentry case series, no implants lost additional bone and
no additional bone augmentation procedures were performed,
however, mucogingival procedures were performed for soft
tissue improvement.

47. • The consistent bone formation in all implants, as clinically
documented in this and another previous study, using specific or
different regenerative surgical approaches is reasonably
encouraging in the treatment of peri-implantitis– affected implants.
• This helps avoid additional surgeries, reducing cost and time
required to replace failed implants.
• There is no evidence that implant surface characteristics can have a
significant effect on the initiation and defect morphology.
• Based on these clinical data, surface characteristics are not a
discriminating factor for bone regeneration, in contrast to the
findings of a previous study.
• Thus, it may be concluded that a regenerative approach for the
treatment of peri-implantitis defects yielded positive clinical results
and could influence the decision of whether implants should be
removed or treated.
• It is necessary to observe a larger number of cases for a longer
period to verify whether osseous regeneration is sufficient to
ensure favorable long-term maintenance of the implants.

48. Conclusions
• The aim of this reentry study was to evaluate the results of
regenerative surgery in peri-implant defects by comparing pre- and
posttreatment assessments of nine implants in six patients.
• A mean bone fill value of 91.3%, with a mean bone gain of 4.33
mm, was obtained. Strict methods of implant surface
decontamination and detoxification were provided for all patients in
this study, regardless of implant surface characteristics.
• The regenerative technique has been performed with minor
changes to both nonsubmerged and submerged approaches.
• No implants lost additional bone or required additional bone
augmentation procedures.
• The present regenerative procedure was effective in treating
moderate to advanced peri-implantitis lesions without
compromising the previous fixed implant-supported prostheses.

49. • The preliminary results are encouraging, as seen by the fact
that bone gains were reported in all cases.
• Nevertheless, caution must be exercised in determining
whether reosseointegration has occurred, because it is not
possible to measure bone implant threads contact in clinical
practice.
• Studies with a large sample size and long-term postsurgical
observation are necessary to demonstrate the ideal protocol
and continued success in the treatment of peri-implant
defects.