J Periodontol • June 2010

Case Report
Double Flap Incision Design for Guided Bone Regeneration:
A Novel Technique and Clinical Considerations
Yong Hur,* Teppei Tsukiyama,* Tae-Ho Yoon,† and Terrence J. Griffin*

Background: Premature membrane exposure for
guided bone regeneration may result in complications, such as inadequate bone regeneration, inflammatory reactions, and wound infection. This paper
presents a clinical case of a novel incision-flap designused to advance the flap to enhance tension-free primary closure for the vertical ridge augmentation.
Methods: A 61-year-old white man presented withthe chief complaint of wanting to replace his posterior
mandibular teeth. A severe alveolar bone deformity
vertically and horizontally (Seibert Class III) was noticed, especially over the mental foramen area. A
staged guided bone regeneration procedure prior to
the implant installation was chosen as the most optimal treatment. A partial-thickness flap, separating
the mucosal flap from the periosteum overlying thealveolar bone, was used to advance the flap.
Results: During the healing period, neither soft tissue dehiscence nor membrane exposure were noted.
Clinical and radiographic evaluation revealed a 4- to
5-mm gain in vertical height and a noticeable increasein horizontal thickness. After the 6 to 8 months of healing for both sites, two implants were placed on eachside with good primary stability and without complications.
Conclusions: This technique facilitates flap advancement by the tension-free nature of the designand enhances soft tissue maintenance during thecourse of regeneration. This approach, the separationof the periosteal layer and the mucosal layer, can beused as an alternative to overcome some of the limitations with conventional technique. J Periodontol
2010;81:945-952.
KEY WORDS
Alveolar ridge augmentation; bone transplantation;case report; dental implants; surgical flaps.

* Department of Periodontology, Tufts University School of Dental Medicine,
Boston, MA.
† Department of Prosthodontics and Operative Dentistry, Tufts University
School of Dental Medicine.

The past two decades of clinical and scientific investigation have established the use of
guided bone regeneration (GBR) as a provenmethod to regain a diminished alveolar ridge.1-5 The
success of GBR has increased the use of dental
implants and has pushed the boundaries of science,with many clinicians experimenting with a variety
of membranes, such as bioabsorbable and nonabsorbable types.6-8 The continuous advancementof GBR has raised clinician and patient expectationsof outcomes that recreate normal occlusal function,
healthy soft and hard tissue anatomy, and esthetics
that resemble the ideal.
Attention must be paid to the case-specific natureof GBR to achieve the best clinical results. The outcome can be affected by various factors including patient habits,9,10 defect morphology,11 cortical bone
preparation,12 materials used,13-15 and membranestability.16 Membrane exposure is one of the most significant factors because it inhibits the amount of regenerated bone possible.17 In 40% to 60% of cases
reported with exposure, there is up to 50% to 80% lessbone regenerated compared to non-exposure.17-19
Therefore, it is clearly beneficial for the clinician toprevent premature exposure of the surgical site whenusing GBR.
Because it has been shown to play a critical role insuccessful primary closure, the anatomy of surgicalsites requiring GBR has been the subject of much research. This type of investigation has yielded information about incision location and blood supply. Due toan avascular zone located over the edentulous ridge
about 1 to 2 mm wide, as demonstrated by a recent
human cadaver study,20 it may be inferred that midline incisions and vertical-releasing incisions at theanterior border of the alveolar ridge are the most promising. A recent human clinical trial that also discusses
blood supply and incision location21 favors mid-crestal
incisions. Based on the mentioned studies, mid-crestal
incisions on the edentulous ridge with a possible vertical
incision on the mesial aspect of the flap seem to yield
the most anatomic potential for success.
doi: 10.1902/jop.2010.090685

945

Double Flap Incision Design for Guided Bone Regeneration

Along with anatomically guided placement of incisions, various clinical protocols and techniques havebeen introduced to enhance primary closure as a meansof preventing premature exposure. Langer andLanger,22 Buser et al.,23 Tinti and Parma-Benfenati,24
and Fugazzotto25,26 propose using an overlapped flap
design, a coronally positioned flap, or a pedicle flap
technique as effective means to obtain primary closure
during the regenerative period. Integral to flap design isthe inclusion of a releasing incision to ensure a tensionless closure. The application of a releasing incision forflap advancement in the mandibular posterior is often
complicated by the precarious proximity of the mental
foramen. Despite the fact that a releasing incision in theposterior mandible is hazardous and should certainly
be avoided, it is frequently necessary especially whenusing vertical augmentation.
Vertical ridge augmentation in preparation for dental implants is one of the most unpredictable procedures in dentistry, but is commonly sought in theposterior, mandible. Few modalities exist to augment
this area; they include autogenous block bone augmentation, distraction osteogenesis, and GBR witha titanium-reinforced barrier membrane for protection
from mechanical forces. All of these approaches havebenefits, but GBR with titanium-reinforced barrier
membrane is the least invasive, has one surgical site,and has the least jaw bone–related complications. As
mentioned previously, however, any GBR procedure’s outcome may be compromised by delayed
healing or premature exposure.
The purpose of this paper is to present a simple incision-flap design that provides tension-free primaryclosure when creating space for guided bone regeneration. The authors present a clinical case using one
subject to demonstrate the double flap incision approach for extensive vertical and horizontal ridge augmentation in the posterior of the mandible near themental foramen. Clinical considerations, such as anatomic difficulty of the region, blood supply, and thebasic concept of an ideal incision flap, are discussed.
CASE DESCRIPTION AND RESULTS
In August 2007, a 61-year-old white man presented toTufts University School of Dental Medicine, Boston,
Massachusetts, with the chief complaint of wanting
to replace his posterior mandibular teeth. He described that he had been edentulous in the area for>30 years without function. The patient’s medical
history was non-significant for major conditions or allergies and free of contributory factors (e.g., systemic
disease and smoking), making him an ideal surgicalcandidate.
Upon interdisciplinary consultation, implantsupported fixed partial prostheses were deemed theappropriate treatment for the sites. However, the946Volume 81 • Number 6

patient’s comprehensive oral evaluation revealed severe alveolar bone deformity vertically and horizontally (Seibert Class III).27 A radiographic evaluation
using CT scanning with a computerized program‡confirmed the insufficient vertical and horizontal bonevolume to accept ideal implant placement. The defects were noticed especially over the mental foramen
area. A staged approach including a GBR procedure
before the implant installation was decided as themost optimal treatment.
Surgical Procedure
The surgical procedure adopted to release tension forflap advancement includes a partial-thickness flap elevation leaving the periosteal layer on the edentulous
ridge and separation of the mucosal layer of the flap
(Figs. 1A through 1I). The periosteal layer of the flap
is used to stabilize the regenerative site using periosteal sutures.
Mandibular Left Quadrant
After appropriate written informed consent, local
anesthesia was attained using three carpules oflidocaine§ with 1:100,000 epinephrine. A crestal incision with a vertical-releasing incision 2 mm away fromthe most distal existing tooth was performed witha #15 blade. The crestal incision was then extended
toward the distal side of the flap to avoid tension.
Then a partial-thickness flap separating the mucosal
flap from the periosteum overlying the alveolar bone
was made on the buccal side. After enough separation
between the external (mucosal) and internal (periosteal) flap was achieved, the periosteal flap was reflected from the bony surface (Figs. 2A and 2B). A
lingual full-thickness mucoperiosteal flap was thenelevated. Decortication was performed using a #2
round carbide bur on the buccal side of the alveolarbone to enhance osteogenesis. Subsequently, a titanium reinforced expanded polytetrafluoroethylene(e-PTFE) membranei was used to create a space freefrom soft tissue. The membrane was trimmed withsurgical scissors to match the defect size and the buccal portion of the membrane was stabilized with one
bone tack.¶ The membrane was appropriately shaped
to extend 3 to 4 mm beyond the defect margins and toallow a close adaptation of the membrane to bone.
The defect was filled with 1.5 cc of mineralized
freeze-dried bone allograft.# The lingual side of themembrane was tucked under the reflected lingual
flap. The periosteal flap was positioned and stabilizedwith 5-0 e-PTFE sutures** using two horizontal‡ iCATVision, Imaging Sciences International, Hatfield, PA.
§ 2% Xylocaine HCL, DENTSPLY, York, PA.
i Gore-Tex Regenerative Membrane, W. L. Gore and Associates,
Flagstaff, AZ.
¶ ACE Surgical, Brockton, MA.
# MinerOss, Osteotech, Eatontown, NJ.
** Gore-Tex Suture, W. L. Gore and Associates.

J Periodontol • June 2010

Hur, Tsukiyama, Yoon, Griffin

Figure 1.
A) Crestal incision on the edentulous ridge and one vertical releasing incision are outlined. Note that the vertical incision is separated from attachment
apparatus of the tooth. B) The double flap incision design is made leaving the periosteum on the edentulous ridge. C and D) The mucosal layer of the
double flap is elevated leaving the periosteal layer. E and F) The periosteal layer of the double flap is elevated exposing the alveolar bone. G) Occlusal
view of the double flap. Note that the vertical incision has reached the mucogingival junction on the lingual side to release the tension. H) The periosteal
layer of the double flap is sutured to stabilize the grafted site. I) Buccal view after final suturing.

mattress sutures (Figs. 2C and 2D). A tension-free adaptation of the wound margins was confirmed before
final closure. Then the mucosal flap was closed using
multiple simple interrupted sutures with 5-0 polyglactin 910†† (Fig. 2E).
The patient was instructed not to wear any prostheses to avoid pressure over the surgical site. The
patient was also told not to chew or brush in the treatedarea for approximately 3 weeks. The home use ofchlorhexidine was suggested for chemical plaquecontrol (0.12%, 1-minute rinse, two times a day for
3 weeks). The patient was instructed to apply an extraoral cold pack to the surgical area frequently during
the first 3 days after surgery to reduce postoperativeswelling. The sutures were removed at the 2-week
postoperative visit. The patient was recalled at 1week intervals until soft tissue healing was completed.
Subsequently, the patient was seen every 4 weeks.
During the healing period, no soft tissue dehiscenceor membrane exposure was noted. The membrane
was left in place for a healing period of 8 months. Clin-

ical and radiographic evaluation, which included CT,
revealed a 3- to 4-mm gain of vertical height alongwith noticeable horizontal thickness (Fig. 2F).
Mandibular Right Quadrant
The surgical site was the contralateral edentulous area
within the same patient. Even though the overall procedure was the same on both sides, the need for height was
greater on the right side because of the proximity of themental foramen in the right quadrant (Figs. 3A and 3B).
A narrow platform implant or regular platform implantwith vertical augmentation was suggested. After interdisciplinary consultation, bone augmentation prior to
the implant installation was determined as the best approach. Autogenous cortical bone was harvested witha bone scraper‡‡ and mixed with 1 cc of freeze-driedbone allograft. The e-PTFE membrane was trimmed
to avoid the mental foramen location. A bone tackwas used to stabilize the regenerative site (Figs. 4A†† Vicryl, Ethicon, Somerville, NJ.
‡‡ Safescraper, META, Reggio Emilia, Italy.

947

Double Flap Incision Design for Guided Bone Regeneration

Volume 81 • Number 6

Figure 2.
Mandibular left quadrant. A and B) After the mucosal flap was elevated, the periosteal flap was reflected from the alveolar bone. C) The
periosteal flap was held with two horizontal mattresses using 5-0 e-PTFE sutures to position and stabilize the membrane. D) Sagittal section of thesurgical site. Note, the periosteal layer of the double flap was separated and used for membrane stability. The mucosal layer helped to releaseflap tension through its separation from the periosteal layer. E) The incision was closed with multiple, simple interrupted sutures using 5-0 polyglactin
910. F) Clinical evaluation revealed vertical and horizontal gain of alveolar ridge in the left posterior mandible after 8 months of healing.

Figure 3.
A) Presurgical CT image of the right posterior mandible revealed a need for 4 to 5 mm in vertical height because of the location of the mental
foramen. B) Clinical picture of the mental foramen on the right posterior mandible after flap elevation. Note that the location of the mental foramen
would interfere with ideal implant placement to avoid a mesial cantilever of implant-supported crown and bridges. The splitting between the periosteal
layer and the mucosal layer is over the mental foramen, which could easily be visualized using this technique.

through 4C). After completion of the procedure, thepatient was seen with the same recall schedule as
the other site. During the healing period, neither soft tissue dehiscence nor membrane exposure were noted.
The membrane was left in place for a 6-month healing
period. Clinical and radiographic evaluation revealeda 4- to 5-mm gain in vertical height and a noticeable increase in horizontal thickness (Fig. 4D).
After 6 to 8 months of healing for both sites, two
implants were placed on each side with good primary stability and without complications (Figs. 4E
and 4F).
948

DISCUSSION
Periosteal fenestration is a commonly used techniquefor flap advancement in conjunction with vertical-releasing incisions. However, there are limitations andcomplications, such as swelling, bleeding, and patient
discomfort when periosteal fenestration is used for
major flap advancement (>7 mm) that requires a deep
incision into the submucosa.28 A greater depth of incision may lessen the blood supply from the vestibuleand compromise the vascularity of the flap becausea major source of blood to the flap comes from the mucosa toward the coronal aspect.29 This also could be

J Periodontol • June 2010

Hur, Tsukiyama, Yoon, Griffin

Figure 4.
Mandibular right quadrant. A) Buccal view of the right posterior mandible. B) The freeze-dried bone allograft mixed with autogenous corticalbone was placed. The e-PTFE membrane was trimmed around the mental foramen location. C) The double flap technique was used for periosteal sutures.
D) Clinical evaluation revealed vertical and horizontal gain of alveolar ridge after 6 months of healing in the right posterior mandible. E) Clinical pictureof bilateral implant placement after 6 to 8 months of healing. All implants were placed with good primary stability and without complications.
F) Radiographic image of final restorations 1-year after loading.

Figure 5.
Maxillary right quadrant with the periosteal fenestration. A) Buccal view with ridge deformity. B) The periosteal fenestration was used in theright side. C) The e-PTFE membrane was stabilized with titanium tacks. D) Occlusal view after final suturing. E) Two-week follow-up after the procedure. F)
Clinical evaluation at 6 months revealed gain of alveolar ridge in the right posterior maxilla.

a negative factor for maintaining primary closure that
increases possible premature exposure on the surgical sites because this often creates more bleeding
and swelling of the tissues, which causes tension on
the incision line.
Flap advancement around the mental foramen isoften compromised and must be managed carefully

to avoid possible damage due to the complexity ofmental nerve branches.30 When conventional techniques are used, the surgeon encounters limitations
on the area. The difficulties could be explained because the area may have insufficient flap advancement when a shallow periosteal fenestration is used.
It may have more of a chance of paresthesia and949

Double Flap Incision Design for Guided Bone Regeneration

Volume 81 • Number 6

Figure 6.
Maxillary left quadrant with the double flap. A) Buccal view with ridge deformity. B) The double flap was used in the left side. C) The
e-PTFE membrane was stabilized with titanium tacks. D) Buccal view after final suturing. E) Uneventful healing after a 2-week follow-up. Note that the
double flap side showed limited swelling, less redness, with more advanced healing compared to the periosteal fenestration side. The patient also reported
better postoperative comfort and less swelling for this site. F) Clinical evaluation at 6 months revealed gain of alveolar ridge in the left posterior maxilla.

Figure 7.
A) The mucosal layer of the double flap is elevated leaving the periosteal layer. B) Uneventful healing after a 2-week follow-up. C) Clinical view
after 6 months healing.

Figure 8.

Diverse double flap applications. A) A collagen membrane§§ was covered and stabilized with sutures over the periosteal layer. B) The double flap was initiatedat a lower position because of the thin gingival tissue <2 mm. A collagen membrane was used. C) A titanium meshii was used for theregenerative site with the double flap.

§§ OSSIXPLUS, Orapharma, Warminster, PA.
ii ACE Surgical.

950

Hur, Tsukiyama, Yoon, Griffin

J Periodontol • June 2010

complications when a deep periosteal fenestration isplaced. Recently, a dome-shaped incision was introduced as a possible solution for the area.28
The new incision-flap design described in this paper for GBR is a practical technique with no significant
side effects. Since its development 2 years ago in
the Department of Periodontology at Tufts University
School of Dental Medicine, a reduced amount of soft
tissue complications including dehiscence, edema,
necrosis, and exposure were observed by the residents and faculty compared to the periosteal fenestration (Figs. 5A through 5F and 6A through 6F). The
main advantage of the double flap incision design isa significant amount of reduction of tension resulting
from the separation of the periosteal layer and the mucosal layer. This technique facilitates flap advancement by the tension-free nature of the design
because the tension is mainly from the dense periosteum under the flap. Diverse regenerative materials,
such as non-resorbable and resorbable membrane
and titanium mesh with different size and locations,can be used with this incision design (Figs. 7A through7C and 8A through 8C). There has not been any instance of paresthesia of the mental nerve when using
this technique. The authors postulate that the periosteal layer of the double flap could possess some nerve
branches compared to being severed by a deep periosteal fenestration technique, each flap layer could
get a separate blood supply from the vestibule, andthe wide surfaces between the two flaps could enhance the healing.
A mesial vertical-releasing incision was placedthat was separated from the tissue surrounding
the adjacent teeth in the cases described previously. When the vertical-releasing incision is located without touching the attachment apparatus ofteeth, the following benefits were observed: 1) easeof the double flap incision, 2) fast healing without contamination from the tooth, and 3) no recession on theadjacent tooth. However, its application could be limited because membrane location should be distalized
to avoid contamination from the incision line. This incision-flap design is ideally used from the alveolar bone
crest when there is enough soft tissue thickness >2
mm. Surgeons could initiate the double flap at a lower
position when it comes to a thin tissue <2 mm because
the apical mucosal part is thicker than the coronal area
(Fig. 8B).
CONCLUSIONS
The results of this paper are based on clinical observation of the technique by the residents and facultyof the Department of Periodontology at Tufts University School of Dental Medicine. Further studies including randomized controlled clinical trials are required
to investigate this technique.

ACKNOWLEDGMENTS
The authors thank Drs. Lydia Gardner, Charles
Hawley and Ishita Seth of Tufts University School of
Dental Medicine, Boston, Massachusetts, for theirinvaluable support. The authors report no conflictsof interest related to this case report.
REFERENCES
1. Dahlin C, Linde A, Gottlow J, Nyman S. Healing ofbone defects by guided tissue regeneration. Plast
Reconstr Surg 1988;81:672-676.
2. Dahlin C, Sennerby L, Lekholm U, Linde A, Nyman S.
Generation of new bone around titanium implants
using a membrane technique: An experimental
study in rabbits. Int J Oral Maxillofac Implants 1989;4:
19-25.
3. Becker W, Becker BE. Guided tissue regeneration
for implants placed into extraction sockets and for
implant dehiscences: Surgical techniques and casereport. Int J Periodontics Restorative Dent 1990;10:376-391.
4. Buser D, Brägger U, Lang NP, Nyman S. Regeneration and enlargement of jaw bone using guided
tissue regeneration. Clin Oral Implants Res 1990;1:22-32.
5. Simion M, Baldoni M, Zaffe D. Jawbone enlargement
using immediate implant placement associated witha split-crest technique and guided tissue regeneration.
Int J Periodontics Restorative Dent 1992;12:462-473.
6. Fugazzotto PA, Shanaman R, Manos T, Shectman R.
Guided bone regeneration around titanium implants:
Report of the treatment of 1,503 sites with clinicalreentries. Int J Periodontics Restorative Dent 1997;17:292, 293-299.
7. Jovanovic SA, Spiekermann H, Richter EJ. Boneregeneration around titanium dental implants in dehisced defect sites: A clinical study. Int J Oral Maxillofac Implants 1992;7:233-245.
8. Nevins M, Mellonig JT, Clem DS 3rd, Reiser GM, BuserDA. Implants in regenerated bone: Long-term survival.
Int J Periodontics Restorative Dent 1998;18:34-45.
9. Saldanha JB, Pimentel SP, Casati MZ, et al. Guided
bone regeneration may be negatively influenced by
nicotine administration: A histologic study in dogs.
J Periodontol 2004;75:565-571.
10. César-Neto JB, Benatti BB, Sallum EA, Sallum AW,
Nociti FH Jr. Bone filling around titanium implants
may benefit from smoking cessation: A histologic
study in rats. J Periodontol 2005;76:1476-1481.
11. Vanden Bogaerde L. A proposal for the classificationof bony defects adjacent to dental implants. Int J
Periodontics Restorative Dent 2004;24:264-271.
12. Majzoub Z, Berengo M, Giardino R, Aldini NN, Cordioli
G. Role of intramarrow penetration in osseous repair:A pilot study in the rabbit calvaria. J Periodontol
1999;70:1501-1510.
13. Zitzmann NU, Naef R, Scharer P. Resorbable versus
nonresorbable membranes in combination with BioOss for guided bone regeneration. Int J Oral Maxillofac
Implants 1997;12:844-852.
14. Simion M, Dahlin C, Trisi P, Piattelli A. Qualitative andquantitative comparative study on different fillingmaterials used in bone tissue regeneration: A controlled clinical study. Int J Periodontics Restorative
Dent 1994;14:198-215.
951

Double Flap Incision Design for Guided Bone Regeneration

15. Simion M, Baldoni M, Rossi P, Zaffe D. A comparative
study of the effectiveness of e-PTFE membranes
with and without early exposure during the healing
period. Int J Periodontics Restorative Dent 1994;14:
166-180.
16. Palmer RM, Floyd PD, Palmer PJ, Smith BJ, Johansson
CB, Albrektsson T. Healing of implant dehiscence
defects with and without expanded polytetrafluoroethylene membranes: A controlled clinical and histologicalstudy. Clin Oral Implants Res 1994;5:98-104.
17. Machtei EE. The effect of membrane exposure on theoutcome of regenerative procedures in humans: A
meta-analysis. J Periodontol 2001;72:512-516.
18. Mellonig JT, Triplett RG. Guided tissue regenerationand endosseous dental implants. Int J Periodontics
Restorative Dent 1993;13:108-119.
19. Becker W, Dahlin C, Becker BE, et al. The use of
e-PTFE barrier membranes for bone promotion
around titanium implants placed into extraction
sockets: A prospective multicenter study. Int J Oral
Maxillofac Implants 1994;9:31-40.
20. Kleinheinz J, Büchter A, Kruse-Lösler B, Weingart D,
Joos U. Incision design in implant dentistry based on
vascularization of the mucosa. Clin Oral Implants Res
2005;16:518-523.
21. Park SH, Wang HL. Clinical significance of incision
location on guided bone regeneration: Human study.
J Periodontol 2007;78:47-51.
22. Langer B, Langer L. Overlapped flap: A surgicalmodification for implant fixture installation. Int J
Periodontics Restorative Dent 1990;10:208-215.
23. Buser D, Dula K, Belser UC, Hirt HP, Berthold H.
Localized ridge augmentation using guided bone regeneration. II. Surgical procedure in the mandible. Int
J Periodontics Restorative Dent 1995;15:10-29.

952

Volume 81 • Number 6

24. Tinti C, Parma-Benfenati S. Coronally positioned
palatal sliding flap. Int J Periodontics Restorative Dent
1995;15:298-310.
25. Fugazzotto PA. Maintenance of soft tissue closure
following guided bone regeneration: Technical considerations and report of 723 cases. J Periodontol 1999;
70:1085-1097.
26. Fugazzotto PA. Maintaining primary closure after
guided bone regeneration procedures: Introduction ofa new flap design and preliminary results. J Periodontol 2006;77:1452-1457.
27. Seibert JS. Reconstruction of deformed, partiallyedentulous ridges, using full thickness onlay grafts.
Part I. Technique and wound healing. Compend Contin
Educ Dent 1983;4:437-453.
28. Greenstein G, Greenstein B, Cavallaro J, Elian N,
Tarnow D. Flap advancement: Practical techniques
to attain tension-free primary closure. J Periodontol
2009;80:4-15.
29. Mörmann W, Ciancio SG. Blood supply of humangingiva following periodontal surgery. A fluoresceinangiographic study. J Periodontol 1977;48:681-692.
30. Mraiwa N, Jacobs R, Moerman P, Lambrichts I, van
Steenberghe D, Quirynen M. Presence and course of theincisive canal in the human mandibular interforaminal
region: Two-dimensional imaging versus anatomical
observations. Surg Radiol Anat 2003;25:416-423.
Correspondence: Dr. Yong Hur, Department of Periodontology, Tufts University School of Dental Medicine, 1
Kneeland Street, Boston, MA 02111. Fax: 617/6360911; e-mail: Yong.Hur@tufts.edu.
Submitted December 7, 2009; accepted for publication
January 23, 2010.