CaaNHa

b

AA

A

Womdml(o©

K

I

Si

HT

((km

0

British Journal of Oral and Maxillofacial Surgery 51 (2013) 880–886

Available online at www.sciencedirect.com

ontainment and contouring (CoCoon) technique:biologically adequate approach to less invasiveutogenous preimplant augmentation of boneils-Claudius Gellrich a,∗, Kai-Hendrik Bormann a, Shahram Tehranchian a,orst Kokemüller a, Maria Mercedes Suarez-Cunqueiro a,b

Department of Oral and Maxillofacial Surgery, Hannover Medical School, GermanyDepartment of Stomatology, Santiago de Compostela University, Spain

ccepted 2 November 2012vailable online 4 December 2012

bstract

e have analysed retrospectively whether the less invasive zygomatic buttress graft is able to meet the dimensional and biological requirementsf preimplant augmentation of bone. A total of 273 patients were treated by zygomatic buttress graft, of whom 42 (12 men and 30 women)et the criteria for inclusion. Intensity of pain was judged by a visual analogue score (VAS). Complications of grafting were evaluated, and

ental implants were studied on clinical and radiographic examinations. The Schneiderian membrane was perforated in 13 cases (28%). Theean (SD) postoperative VAS was 3.1 (0.9) at the donor site. The mean (SD) follow-up after implant was 17(8) months. Two grafts were

ost, one from initial dehiscence and later infection, and the other from infection. The mean (SD) marginal resorption of bone graft was 0.50.7) mm. No implant was lost during the observation period. The zygomatic buttress graft meets the biological and dimensional requirementsf augmentation of bone before implant that allows the dental implants to survive with satisfactory prosthetic rehabilitation.

2012 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

eywords: Zygomatic buttress; Maxillary augmentation; Alveolar ridge defect; Dental implant

D

ntroduction

uccessful rehabilitation of an atrophic jaw with a prostheticmplant requires bone grafting for alveolar reconstruction.1

∗ Corresponding author at: Department of Oral and Maxillofacial Surgery,annover Medical School, D-30625 Hannover, Germany.el.: +49 5115324748; fax: +49 5115324740.

E-mail addresses: Gellrich.Nils-Claudius@mh-hannover.deN.-C. Gellrich), Bormann.Kai-Hendrik@mh-hannover.deK.-H. Bormann), S.Tehranchian@gmx.de (S. Tehranchian),okemueller.horst@mh-hannover.de (H. Kokemüller),ariamercedes.suarez@usc.es (M.M. Suarez-Cunqueiro).

rifiotpdsBma

266-4356/$ – see front matter © 2012 The British Association of Oral and Maxillofaciahttp://dx.doi.org/10.1016/j.bjoms.2012.11.001

espite considerable research into new biomaterials for bonyegeneration, an autograft is still the gold standard. Severalntraoral donor sites for bone grafts have been describedor the reconstruction of atrophic maxillas,2–7 but anatom-cally shaped bone grafts with no need for further shapingf the harvested bone are rare in the oral cavity. Conven-ional bone grafting protocols generally require the greatestossible bone to bone contact; in other words, focus isirected towards the interface between the recipient boneurface and the corresponding underside of the graft itself.

efore grafting the recipient bone surface often requiresanipulation such as curettage, roughening of the surface,

nd drilling of holes to improve connectivity and healing

l Surgeons. Published by Elsevier Ltd. All rights reserved.

al and Maxillofacial Surgery 51 (2013) 880–886 881

as

tdoh

P

P

AOwvbfiaawImwn

otmoh

omh

O

A(Imaatdrawijzs

w

Fig. 1. Donor site at the alveolar zygomatic crest. The bone was cut with ap

bcsPa

cmiatot(bfls4G

N.-C. Gellrich et al. / British Journal of Or

t the interface between the grafted bone and the originalurface.8

The aim of this retrospective study was to find out whetherhe less invasive zygomatic buttress graft is able to meet theimensional and biological requirements for augmentationf bone before implantation in the case of a defect in theorizontal alveolar crest.

atients and methods

atients

total of 273 consecutive patients from the Department ofral and Maxillofacial Surgery, Hannover Medical School,ere enrolled in the study. No patient had an adequateolume of bone for conventional placement of implantsecause of atrophy of the horizontal alveolar ridge. Insuf-cient bony volume was defined as an implant diameterdequate to the functional requirements plus 1.5 mm of boneround the implant. In all cases the bone was regeneratedith a zygomatic buttress graft before the implant was placed.

nformed consent was obtained from all patients before place-ent of the implant. Because the study was retrospective itas granted a written exemption by the University of Han-over IRB.

The inclusion criteria were: patients who were partiallyr fully edentulous with a deficiency in the horizontal bonehat needed a graft for up to 2 implants; patients who had no

edical or psychological problems; patients aged 70 yearsld or less; and patients who were treated throughout in ourospital.

The exclusion criteria were: patients who were pregnantr breast-feeding; patients who smoked; patients with anyedical problem during follow-up; and patients who did not

ave good oral hygiene.

perative technique

ll patients were operated on under local anaesthesiaUltracain® D-S forte, Aventis Pharma, Frankfurt, Germany).f the bony defect was in the posterior maxilla (premolar-olar region), the horizontal incision on the donor grafting

rea was made in the buccal aspect of the maxilla, 3–5 mmbove the mucogingival junction from the first premolar tohe second molar, with two vertical incisions mesial andistal to the horizontal incision. If the bony defect was ante-ior (incisor-canine region), the horizontal incision was madelong the edentulous ridge and the sulcus of the adjacent teeth,ith a distal release that continued into a horizontal incision

n the maxillary vestibule, 3–5 mm above the mucogingivalunction. A mucoperiosteal flap was reflected to expose the

ygomatic buttress. Osteotomy was made with a piezoelectricurgical device (Piezosurgery®, Mectron, Italy) (Fig. 1).

An autograft of cortical bone with a surface of up to 2 cm2

as harvested from the ipsilateral tail end of the zygomaticFa

iezoelectric surgical device.

uttress. Particulated autograft was harvested from the outerortex of the maxilla or mandible with a bonescraper (Safe-craper, Divisione Medicale Meta CGM SpA, Villa, Italy).erforation of the Schneiderian membrane was recorded ascomplication.

An autograft in the form of an arch was placed on the buc-al region, creating a space underneath, and fixed with twoiniscrews (Synthes, Umkirch, Germany) (Fig. 2), 1.3 mm

n diameter and 8–14 mm long. The graft was perforated with1.3 mm drill and basal bone with a 1.0 mm drill so as not

o generate rotating forces. The bone graft was fixed with 2steosynthesis screws. The gap between the original bone andhe arch-shaped graft was filled with particulated bone chipsFig. 3). The autograft was covered with a collagen mem-rane (Bio-Gide, Gleistlich, Wolhusen, Switzerland). Theap was sutured in 2 layers (submucous buried sutures anduperficial single and mattress sutures) without tension using/0 or 3/0 polyglactin 910 (Vicryl®, Ethicon®, Norderstedt,ermany).

ig. 2. Bone graft fixed to the basal bone with miniscrews in the form of anrch.

882 N.-C. Gellrich et al. / British Journal of Oral and

Fc

P

Ab8Gg3iw1

t1wws

C

Ap

eatPiau

pmpo

R

Daivtouoltbcttsm

fista

ig. 3. Bone graft creating a space underneath filled with particulated bonehips. Collagen membrane is covering the bone graft.

ostoperative instructions

n antibiotic was prescribed only if the Schneiderian mem-rane perforated, in which case we gave amoxicillin 1000 mg-hourly for 5 days (Amoxicillin Rathiopharm GmbH, Ulm,ermany). All patients were given a non-steroidal anal-esic, ibuprofen 600 mg 8-hourly postoperatively for the firstdays. Other postoperative instructions included not allow-

ng the use of a dental prosthesis for 10 days and oral hygieneith 0.2% chlorhexidine solution after brushing teeth for4 days.

Sutures were removed after 10–14 days. Removable pros-heses were not allowed in the reconstructed area for at least0 days more. A fixed prosthesis was allowed if no contactas made with the area of the wound. Afterwards denturesere carefully adjusted and the fitting surface covered with a

oft denture liner to prevent overloading of the grafting area.

linical examination and follow-up

fter a healing period of 3 months, the implant was put inlace (Fig. 4). After a further 3 months the implant was

Fig. 4. Placement of the implant after the graft had healed for 3 months.

P

Tifw

S

NgDamSIs

Maxillofacial Surgery 51 (2013) 880–886

xposed and a superstructure mounted. At this stage wessessed complications at donor sites, integration and resorp-ion of grafts, and suitability for placement of implants.atients were examined 10 days and 6 weeks after graft-

ng; immediately before insertion of the implant; 10 daysnd 6 weeks after insertion; and 3 months after insertion forncovering.

Probing depth was established after placement of the finalrosthesis and at the last follow-up visit. Measurements wereade at 4 sites for each implant with a UNC-15 periodontal

robe (Hu-Friedy, Chicago, IL, USA). We then took a meanf the 4 to produce a final value.

adiographic examination

igital panoramic radiography was taken before grafting,fter grafting, immediately after insertion of the implant, afternsertion of the permanent prosthesis, and at the last follow-upisit. The marginal bone height was calculated by comparinghe panoramic radiograph taken immediately after insertionf the implant (baseline measurement) and at the last follow-p visit. Care was taken to ensure a clear image of the threadsn both sides of the implant. Marginal bone loss was calcu-ated from the digital panoramic radiographs. The length ofhe implant served as a reference point when proportions wereeing established. Marginal bone height was defined as thehange in distance between the shoulder of the implant andhe marginal bone on both the mesial and distal aspects ofhe surface of the implant. A mean was taken of these 2 mea-urements to produce a final value. All measurements wereade by the same tester to avoid intertester differences.The graft was considered to have “survived” when suf-

cient bone remained for proper insertion of an implant. Itsurvival was established when the implant had adequate func-ion and aesthetics, there was no persistent pain or discomfort,nd no signs of mobility were detected.

atients’ perceptions

he intensity of pain was measured 10 days after bone graft-ng using a visual analogue scale (VAS) with values rangingrom 0 (no pain) to 5 (extreme pain). To classify pain patientsere asked to give their perception of the grafting procedure.

tatistical analysis

ormal distribution and equal variance of the data of allroups were calculated. Values are expressed as mean (SD).ifferences between the time points of measurements were

ssessed with the help of the analysis of variance for repeatedeasures, for which we used the Statistical Package for the

ocial Sciences (SPSS, version 16.0, SPSS Inc., Chicago,L, USA). Probabilities of less than 0.05 were accepted asignificant.

al and

R

Aasgotb

garTap

1fitZt(Aob

imlatttiw

o

D

Tafcbbazbsdai

sep“sbaoaettcbcf

dypucbfmsba

lotroh

rNbmautsrw

alui

N.-C. Gellrich et al. / British Journal of Or

esults

total of 42/273 (30 women, mean age 45 and 12 men, meange 38 (range 18–75) years) met the inclusion criteria of thetudy. These 42 patients were given 46 zygomatic buttressrafts. Four patients were given 2 zygomatic buttress graftsbtained from both zygomatic bones. Three zygomatic but-ress grafts were divided into 2 fragments each because theony defect was larger than 2 consecutive teeth.

Two patients were not given implants because their bonerafts failed. One graft was lost from initial dehiscencend later infection, and the other graft discharged pus. Theemaining 40 patients had a total of 55 dental implants.ables 1 and 2 show the results of all patients treated withzygomatic buttress graft. The Schneiderian membrane waserforated in 13 cases (28%) during the grafting procedure.

The mean (SD) duration of follow up of the implant was7 (6) months (range 7–36). The length of implants rangedrom 9 to 13 mm and the diameter from 3.5 to 4.5 mm. Twomplant systems were used: Straumann Dental Implant Sys-em (Basel, Switzerland) and Astra Tech Implants (Astraeneca, Sweden), but there were no specific criteria for selec-

ion. Prosthodontic rehabilitation involved single crownsn = 24), bridges (n = 12), and overdenture prostheses (n = 3).s far as measurement of probing depth was concerned, onlyne implant had a value of more than 3 mm, which was causedy peri-implantitis.

On the panoramic radiographs, the evaluation of 110mplant surfaces (mesial and distal) showed a mean (SD)

arginal bony resorption of 0.45 (0.7) mm between base-ine and the last follow-up (range 0.1–4 mm). In a frequencynalysis, 45 (82%) of the implants had marginal bony resorp-ion of 0.5 mm or less; 3 (6%) had more than 0.5 but lesshan 1 mm; 3 (6%) had more than 1 but less than or equalo 1.5 mm; and 4 implants (7%) had more than 1.5 mm. Nomplant was lost during the observation period. All implantsere successful both aesthetically and functionally.The mean (SD) VAS was 3.1 (0.9) (range 1–5) for post-

perative pain at the donor site.

iscussion

he goal of using zygomatic buttress for grafting is to cre-te sufficient quantity and quality of bone to ensure optimalunctional and aesthetic placement of dental implants. Theontainment and contouring (CoCoon) technique developedy Gellrich et al. and used in our study uses the zygomaticuttress as an area from which to obtain grafts for preimplantugmentation.9,10 Although some authors have proposed theygomatic bone as a donor region,11 they used particulatedone as well for a peri-implant bone defect9,12 or chips for a

7,13

inus lift. However, the CoCoon technique was used forefects in the horizontal bone not only to obtain volume butlso to achieve a pronounced arch, which is fundamentallymportant aesthetically.

otsp

Maxillofacial Surgery 51 (2013) 880–886 883

Traditionally it was considered that contact between theurfaces of grafted and recipient bone was necessary tonsure successful healing. However, our procedure pro-oses an alternative. The CoCoon technique replaces theone-piece” graft as a composite graft. It uses a thin, arch-haped, form-giving, outer bone graft to create a space toe filled with particulate scraped bone chips that serve asn autogenous inner three-dimensional matrix. The shapef the bone graft from the zygomatic crest required nodditional changes in contour except the rounding of sharpdges with a diamond spherical drill. The authors namedhis procedure “the CoCoon technique” referring to the pro-ective shell in which the particulate autogenous bone isontained. The thin cortical bone structure provides lowony resorption after remodelling, probably because revas-ularisation of the inner contained particulate bone is soast.

The zygomatic buttress has important advantages as aonor site. It offers easy access with excellent visibility andields good quality bone with adequate morphology. It alsorovides the advantage of not having to detach muscles. Kain-lainen et al.11 suggested that the maximum harvest withoutausing damage to surrounding tissues should be 0.5–1 ml ofone. We have found that obtaining a bone graft of 1.5–2 cm2

rom the lower zygomatic buttress is viable without compro-ising the strength of the frame of the lateral midface, while

till respecting the Schneiderian membrane and the infraor-ital foramen.14 This amount of bone is sufficient to contourlveolar defects for 1 or 2 implants.

With this technique the probability of nerve damage isow, because the nerves are not close to the anatomical regionf the graft; we found none. Contraindications to harvestinghe zygomatic buttress include atrophy of the zygomatic areaelated to a syndrome or congenital abnormality, and previousperation or trauma to the area.9 Patients should not have aistory of sinus problems.

The use of ultrasound-based dissection with piezosurgeryeduces the danger of perforating the sinus membrane.15,16

evertheless in some cases it is difficult to separate the mem-rane from the bone graft, particularly in patients with a thinembrane. We found 28% of perforated membranes, and

lthough this was high it was lower than that found by Kain-lainen et al.17 who found a total of 33%, probably becausehey used a round bur instead of a piezosurgical device. In aample of 100 patients, Wallace et al.18 found 30% of perfo-ated sinus membranes with rotatory instruments comparedith 7% with piezosurgery.The CoCoon technique is clinically reliable and associ-

ted with minimal morbidity. There was little marginal boneoss and the survival of implants during this short follow-p period was excellent. The arch-shaped bone graft wasdeal, particularly aesthetically for the reconstruction of alve-

lar projection in the anterior maxillary zone. It eliminatedhe need for secondary corrective augmentation of soft tis-ue with fibrous tissue grafts to reconstitute the alveolarrojection.19,20

884 N.-C. Gellrich et al. / British Journal of Oral and Maxillofacial Surgery 51 (2013) 880–886

Table 1Details of patients.

Case no. Sex Age (years) Graft Follow-up ofimplant (months)

Position ofimplant

Length ofimplant (mm)

Diameter ofimplant (mm)

1 F 54 Right 25 11 13 4.02 M 18 Right 17 11 13 3.53 F 75 Left 26 22 12 4.14 M 64 Right 18 15 11 4.55 F 18 Right 21 12 13 3.56 F 19 Left 26 22 11 3.57 F 19 Left 26 12 11 3.58 F 74 Right 26 16 11 5.09 M 56 Left 16 25 11 3.5

26 11 4.510 M 18 Right 8 NK NK NK11 M 18 Left 8 11 13 3.512 F 68 Right 18 14 13 5.0

16 9 5.013 F 18 Right 16 12 12 4.114 F 18 Right 12 12 11 3.5

Left 22 11 3.515 F 36 Left 14 22 13 3.516 M 76 Left 13 23 11 4.017 F 30 Right 12 11 13 4.518 M 20 Left 14 22 13 3.519 F 61 Right 26 14 13 4.0

16 11 5.020 M 22 Right 12 11 13 3.521 M 19 Right 12 12 13 3.522 F 64 Left 24 16 10 4.823 F 22 Left 8 21 11 3.524 F 51 Left 24 14 12 4.125 M 35 Right 36 12 13 4.326 F 25 Left 8 12 13 3.527 F 45 Right 25 26 10 4.828 F 45 Left 7 24 11 4.0

25 11 5.029 F 73 Right 12 13 13 3.530 F 19 Right 12 12 13 3.5

13 11 3.531 F 19 Left 12 NK NK NK32 F 50 Right 13 14 10 4.033 F 51 Left 13 21 11 3.5

22 11 3.534 F 45 Right 28 15 13 4.535 F 66 Left 36 24 11 4.536 F 68 Right 12 14 12 4.137 F 69 Right

Left12 12 9 3.5

14 9 4.522 9 3.525 9 4.0

38 F 45 Right 8 14 11 3.539 M 65 Left 14 27 10 4.8

Right 15 10 4.816 10 4.1

40 F 50 Right 20 12 13 3.5Left 13 13 3.5

22 13 3.523 13 3.5

41 F 40 Left 14 21 12 4.142 M 41 Right 26 11 13 4.5

M, male; F, female; and NK, not known.

N.-C. Gellrich et al. / British Journal of Oral and Maxillofacial Surgery 51 (2013) 880–886 885

Table 2Clinical and radiological characteristics.

Case no. Complicationsof the graft

Mean probingdepth (mm)

Loss ofperi-implantmesial bone (mm)

Loss ofperi-implant distalbone (mm)

Mean loss ofperi-implantbone (mm)

VAS

1 No 2.50 0.60 0.64 0.62 32 MP 1.50 0.21 0.21 0.21 13 No 2.75 2.4 2.6 2.5 24 No 2.5 0.20 0.24 0.22 45 MP 1 0.17 0.21 0.19 36 No 2 0.3 0.3 0.3 27 No 2 0.27 0.27 0.27 28 MP 2.5 1.52 1.50 1.51 49 No 2 0.1 0.1 0.1 4

2 0.2 0.2 0.210 F ND ND ND ND 411 No 1.5 0.33 0.29 0.31 412 No 2 0.17 0.17 0.17 2

2 0.16 0.12 0.1413 MP 1.25 0.21 0.21 0.21 214 No 1 0.15 0.15 0.15 4

1 0.10 0.10 0.115 No 2 1.0 1.20 1.1 316 MP 2.25 0.20 0.20 0.2 317 No 2 0.12 0.12 0.12 218 MP 2 0.36 0.32 0.34 419 No 1.5 0.19 0.19 0.19 3

1.75 0.56 0.52 0.5420 No 1 0.10 0.10 0.1 321 MP 1 0.16 0.12 0.14 422 MP 2 1.5 1.5 1.5 2

D23 No 1 0.1 0.1 0.1 324 No 2.25 1.50 1.56 1.53 325 MP 2 0.2 0.2 0.2 326 MP 1.5 0.12 0.16 0.14 427 No 2 1.17 1.21 1.19 328 No 2 0.45 0.45 0.45 329 No 2 0.1 0.1 0.1 43o MP 2.25 0.25 0.25 0.25 2

2 0.17 0.19 0.1831 F ND ND ND ND 232 MP 2 0.16 0.19 0.17 4

2 0.20 0.20 0.233 No 1 0.20 0.18 0.19 3

1 0.15 0.21 0.1834 No 2 0.14 0.14 0.14 335 No 1 0.39 0.35 0.37 436 No 2 0.20 0.20 0.20 237 No 2 0.25 0.25 0.25 3

2 0.30 0.26 0.282 0.32 0.30 0.314.5 4 4 4.00

38 No 1.25 0.14 0.18 0.16 439 MP 2 0.52 0.52 0.52 3

2 0.38 0.40 0.392 0.30 0.28 0.29

40 No 2 0.20 0.20 0.2 52 0.18 0.18 0.182 0.16 0.14 0.152 0.10 0.10 0.1

41 No 1 0.25 0.21 0.23 242 No 2 0.50 0.52 0.51 3

VAS, visual analogue scale; MP, membrane perforation; D, dehiscence; ND, no data; and F, failed.

8 al and

bmboOt

C

T

R

1

1

1

1

1

1

1

1

1

86 N.-C. Gellrich et al. / British Journal of Or

We recommend the CoCoon technique to meet theiological and dimensional requirements of preimplant aug-entation of bone in an edentulous area. It provides adequate

one and volume with minimal morbidity, allows the survivalf dental implants, and satisfactory prosthetic rehabilitation.ur results support the widespread application of the CoCoon

echnique in the field of horizontal bone augmentation.

onflict of interest

he authors have no conflicts of interest to declare.

eferences

1. Seibert JS. Reconstruction of deformed, partially edentulous ridges, usingfull thickness onlay grafts. Part I. Technique and wound healing. Com-pend Contin Educ Dent 1983;4:437–53.

2. Rabelo GD, de Paula PM, Rocha FS, et al. Retrospective Studyof bone grafting procedures before implant placement. Implant Dent2010;19:342–50.

3. Wolford LM, Cooper RL. Alternative donor sites for maxillary bonegrafts. J Oral Maxillofac Surg 1985;43:471–2.

4. Sethi A, Kaus T. Ridge augmentation using mandibular block bone grafts:preliminary results of an ongoing prospective study. Int J Oral MaxillofacImplants 2001;16:378–88.

5. Clavero J, Lundgren S. Ramus or chin grafts for maxillary sinus inlayand local onlay augmentation: comparison of donor site morbidity andcomplications. Clin Implant Dent Relat Res 2003;5:154–60.

6. Schwartz-Arad D, Levin L. Symphysis revisited: clinical and histologicevaluation of newly formed bone and reharvesting potential of previ-

ously used symphysial donor sites for onlay bone grafting. J Periodontol2009;80:865–9.

7. Johansson LA, Isaksson S, Lindh C, et al. Maxillary sinus floor aug-mentation and simultaneous implant placement using locally harvested

1

2

Maxillofacial Surgery 51 (2013) 880–886

autogenous bone chips and bone debris: a prospective clinical study. JOral Maxillofac Surg 2010;68:837–44.

8. Smukler H, Capri D, Landi L. Harvesting bone in the recipient sites forridge augmentation. Int J Periodontics Restorative Dent 2008;28:411–9.

9. Held U, Bormann KH, Schmelzeisen R, et al. Augmentation of alveolarridge defects: autologous bone transplant from the zygomatic alveo-lar crest – a new technique (French and German). Schweiz MonatsschrZahnmed 2005;115:692–703.

0. Gellrich NC, Held U, Schoen R, et al. Alveolar zygomatic buttress: anew donor site for limited preimplant augmentation procedures. J OralMaxillofac Surg 2007;65:275–80.

1. Kainulainen VT, Sàndor GK, Clokie CM, et al. The zygomatic bone as apotential donor site for alveolar reconstruction—a quantitative anatomiccadaver study. Int J Oral Maxillofac Surg 2004;33:786–91.

2. Kainulainen VT, Sàndor GK, Oikarinen KS, et al. Zygomatic bone: anadditional donor site for alveolar bone reconstruction. Technical note. IntJ Oral Maxillofac Implants 2002;17:723–8.

3. Peleg M, Garg AK, Misch CM, et al. Maxillary sinus and ridge augmen-tations using a surface-derived autogenous bone graft. J Oral MaxillofacSurg 2004;62:1535–44.

4. Dierks EJ, Harper GA. The 4 cardinal bends of the zygomatico-maxillarybuttress: technical note. J Oral Maxillofac Surg 2009;67:1149–51.

5. Vercellotti T, De Paoli S, Nevins M. The piezoelectric bony windowosteotomy and sinus membrane elevation: introduction of a new tech-nique for simplification of the sinus augmentation procedure. Int JPeriodontics Restorative Dent 2001;21:561–7.

6. Robiony M, Polini F, Costa F, et al. Piezoelectric bone cutting in multi-piece maxillary osteotomies. J Oral Maxillofac Surg 2004;62:759–61.

7. Kainulainen VT, Sàndor GK, Carmichael RP, et al. Safety of zygomaticbone harvesting: a prospective study of 32 consecutive patients withsimultaneous zygomatic bone grafting and 1-stage implant placement.Int J Oral Maxillofac Implants 2005;20:245–52.

8. Wallace SS, Mazor Z, Froum SJ, et al. Schneiderian membrane perfora-tion rate during sinus elevation using piezosurgery: clinical results of 100consecutive cases. Int J Periodontics Restorative Dent 2007;27:413–9.

9. Langer B, Calagna L. The subepithelial connective tissue graft. J ProsthetDent 1980;44:363–7.

0. Scharf DR, Tarnow DP. Modified roll technique for localized alveolarridge augmentation. Int J Periodontics Restorative Dent 1992;12:415–25.