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Localized Ridge Augmentation UsingAbsorbable Pins and e-PTFE BarrierMennbranes: A New SurgicaiTectinique. Case Reports

William Becker. DDS.'Burton E. Becker. DDS"Michael K. McGuire, DDS"'

This paper presents o new surgicot technique to promote bone formationin localized alveolar ridge defects. The objective wos to regenérate suffi-cient bone volume for implant placement. The teohnique Is dependent onoarefut defect debridement and the use of absorbaPle orthopedic pins,which serve as tent pales and prevent the e-PTFE Porrier membrones fromcollapsing into the defects. The three defects treoted with this techniquewere completely resolved with new bone, ond implants were successfullyplaced into the augmented ridges. Biopsies trom the treated sitesrevealed new bone formation. (Int J Periodont Rest Dent i 994: i 4:49-01.)

' Department of Periodontics, University of Sauttiern CaliforniaSchool of Dentistry, ond Department of Periodontics,University of Texas at i-iouston.

' Department of Periodontics. University of Texas at Houston.' University of Texas, Health Science Center at Houston

Correspandence to: Dr William Becker. 801 North Wilmot,Suite B2, Tucson. Arizona 85711.

Placement of endosseousimplonts requires sufficientbane volume to stobilize theimplant. After tooth extractionthere is remodeiing of the alve-oior bone. If the tooth is notremoved carefully, looolizeddiscreponcies in the boneoccur; these traumatic injuriescompromise future implantpiocemeht, Similorly, traumaticaccidehts in which teeth oreavulsed coh olso ieod to aive-oiar anatomic defects thatpreclude placemeht of dentalimpionts. The predictoblereconstruction of these types ofdefects con moke it possible torehobilitote patients vi/ith fixedprostheses anchored to endos-seous implants.

The appiicotion of barriermembrane techhology to den-tal implant surgery is a naturalevolution from its acceptedapplication as a recognizedperiodontol regenerative pro-cedure. The use of barriermembrones to separate heal-ing compartments during thehealing process has added anew dimension to periodontoi'-''and implant therapy,^'

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The appiication of mem-brane technoiogy has beenexpanded to inciude treat-ment for impionts piaced intoimmediate extraction socketsand to promote bone aroundimplants with bone dehis-cences and fenestrdtions.Furthermore, barrier mem-branes have been used toaugment aiveoiar ridges withtraumatic injuries and bonedefects. Seibert and Nyman^ocreated extensive ridge de-fects in dogs. The defects weresubsequently augmented withhydroxyapatite and Gore-Texmembranes (WL Gore). Ciinicaiand histoiogic evaiuation dem-onstrated eniargement of theexperimentaliy created de-fects with minimai amounts ofnewly formed bone. Buser andcoworkersi^ treated 12 patientswith iocaiized ridge defectsusing a speciai fiap design ande-PTEE membranes. The mem-branes were dispiaced fromthe aiveoiar ridge by smallscrews. The screws acted astent poies and prevented theaugmentatian material fromcoliapsing against the boneonce the fiaps were sutured.After ó months, 9 of the 12treated patients had sufficientamounts of regenerated bonefor impiant placement. Thegain of bone width varied from1.5 to 5.5 mm.

Simion et aV^ treated fivepatients with narraw buccoiin-gudi dimensions. The ridgeswere spiit. creoting green-stici<fractures, and implants wereinserted. The defects were pro-tected with e-PTFE augmenta-tion material. Biopsies from thetredted sites indicated boneregeneration between the splitcrest.

Shanamon^^ p iaced im-plants into ideal prosthetic posi-tions. This frequentiy resulted inbuccai dehiscences and fenes-trations. Demineralized freeze-dried bone was implanted overthe defects and e-PTFE aug-mentation materiai was piacedover the impianted sites. At thesecond stage, the implantsappeared to be covered by obone-iike materiai.

The purpose of this pilotstudy was to determine if local-ized ridge augmentation couidbe achieved using e-PTFE barri-er membranes with absarbabiepins, which were used to sup-port the barrier membranesand to prevent the materioifrom coiiapsing into the de-fects. The goai was to suffi-cientiy increase the existingbone voiume to place endos-seous implants.

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Method and materials

Three adult patients with evi-dence of localized mandibuiarridge detormities were enrolledin this pilot project. All patientswere initially reterred to ourottices for evaluation for implantplacement. The health status ofthe patients was determinedand each patient received ocomprehensive periodontqievaiuation. Campiete-mouthradiographs and panoramicfilms were taken. When theareas ot possible implantplacement were determinedto be deficient of bone quanti-ty, because of a locaiizedridge detect, linear tomogramsor computer-assisted tomo-grams were made in additionto the periapical films (Figs lo,2a, and 3q). The patients wereconsidered to be in reasonablygood health and were givenextensive explanations ot theprocedures that wouid be per-formed. They then signed surgi-cai consent forms.

The patients were premed-icated with an appropriateantibiotic (amoxioiiiin, 2 g2 hours prior to surgery), andwere prescribed qmcxiciiiin, 1 gper day for 1 week postopera-tively. The patients were anes-thetized with an appropriatelocal anesthetic (Lidocaine 2%,1:100,000 epinephrine). Inci-sions were placed either iinguoi

or buccai to the midaiveolarcrest and extended one toothmesiqi qnd distal to the defect.To achieve proper visualizationot the defects, verticai reieas-ing incisions were piaced atthe anterior fiap extensions,Fuii-thickness muooperiostealtiaps were raised, exposing theunderlying defects (Figs Ib and2b). The defects were thor-oughly debrided with curettesand fiies. To promote bieeding,smaii round burs were used toperforate the bone within thedefects (Fig 3b). Corbide 557burs were used to make 3- to4-mm-deep pin-retention sitesIaterai to and within the defect.

Depending upon defeofanatomy, three to four supportpins were out from an Crtho-Sorb Absorbabie Pin Kit (John-son & Johnson Orthopedics),The pihs are made of polydiox-anone and resorb within 6months. To obtain a snug fit,the pins were siightly reducedin size with either a 557 bur or asurgicol blade. Once the pinswere trimmed, they werepressed into the recipient sites(Figs lc, 2c, and 3b) The pinsextended approximotely 2 to 3mm coronai to the defect. Anappropriately shaped piece ofGore-Tex augmentation mate-riai (WL Gore) was draped overthe defect, extending a mini-mum of 3 to 5 mm over thebuccolinguai defect margins

(Figs Id, 2d, and 3c). The mate-rial wos tucked under the flapmargins, which were closedwith interrupted, horizontalmattress sutures with an at-tempt to ccmpleteiy cover theaugmentation materioi (Figsle, 2e, and 3d). The verticalincisions were sutured withinterrupted sutures. The pa-tients were given appropriateanalgesics. The sutures wereremoved in 1 week and the tis-sues were examined tor moteri-al exposure. The patients wereseen bimonthly tor 2 months, incases where the moteriaibecame exposed, Peridex(Proctor & Gambie) wasappiied to the area of expo-sure with a cotton swab oncea doy (Fig 2t), Complete pho-togrophic documentotion wasmade ot the surgiooi and post-operative visits, in one patient,the material was removed 7weeks after surgery (Fig 3e),

Prior to implant placement,radiographs were taken toevaluate bone healing withinthe treoted defects (Figs If, 2g,and 3f). The radiographs weretaken a minimum of 5 monthsatter the initiai surgery and alldetects exhibited radiographieevidence of aimost total bonedefect resolution. The time ofthe second-stoge surgeryranged trom 5 to 11 months.

At implant placement, thetissues overlying the material

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appeared healthy (Figs lg and2f), Buccplingual muooperi-osteal flaps were elevated,exposing the retained mem-branes (Figs Ih and 2h). Theremaved membranes, withsmall quantities of underlyingbone and a core biapsy fromone sife, were fixed in 10% neu-tral buffered formalin andprocessed far histologie evalu-ation (Fig 3h). The sectionswere stained with hematoxylinand eosin. The purpose af thebiopsies was to determine thequaiity of the regeneratedbone.

There was bone regenera-tion in each of fhe treateddefects (Figs l i , 2i, and 3g). Foreach of the treated detects,there was sufficienf bone vai-ume for placement ot endos-seous implants (Figs lj, 2j, and3i). The impiant sites were pre-pared according to the meth-od of Adeii and coworkers,'"and appropriateiy sized im-plants (Nobelpharma) wereprecisely piaced into the pre-pared sites. Cover screws werefixed to the implants, and theflaps were sutured with inter-rupted mattress sutures. Siximplants were successfullyplaced in the regeneratedalveolar ridges of fhe threepatients.

Results

Figures la to l i , 2a to 2m, and3a to 3j demonstrate the sur-gioal technique and clinicalresuits affer freatment of theGiveoiar ridge defects in fhispilot project. The materialbecame expased in two of thethree patients. In one patientthe material and pins wereremoved 6 weeks after place-ment. In another patient asmall pieoe of materialbecame exposed, but wasretained until the time ofimplant placement. The materi-al remained unexposed in thethird patient. The augmenta-tion pracedures increased thebone volume sufficiently toallow placement ot endos-seous implants in each of thetreated ridge deformities.

Evaluation of biopsies

The biopsies taken from eachaf the augmented sitesdemonstrated vital bone.Figure II demonstrates a sec-tion thraugh the e-PTFE mem-brane and underlying bone.The membrane was remavedat the time of implant place-ment. The bone is representa-tive of woven bone. Os-feocyfes are present andosteablasts line the boneseams. Figure 2j, a section fromfhe bone core taken at thetime of implant placement,demonstrates a clear demar-cation between mature andthe newly regenerated bone.

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fig la Rodiogrophs reveal a deep,wide, crater-like defect between themandibular ieff second premolar andloterol incisor.

Fig Ib (leff) After flap reflection, ihedefect was thoroughly debrided

Fig Ic (right) Twa resatbabte pinswere ploced info prepared sites an thebuccol aspect af fhe defect and anepin wos inserted in the center of thedefect. The pins extended 2 to 3 mmcoronol fo the detect

Fig I d (leff) An Ovoi ó piece afGore-lex ougmentafion material wasdraped over the pins.

Fig Ie (right) Horizonlol moftresssutures were used to coopt ihe flapmargins.

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Fig If (left) Radiograph taken dt thetime of impldnt pidcement. Note com-plete bone regenerotion of previousdetect

Fig Ig (right) The materiol remainedcovered for 11 months. The photo-graph reveals tissue health over theaugmented ridge.

Fig lt\ Buccdlingual flaps have beenreflected, revealing the augmentationmateridi totdily integrdted with theunderlying bone. The material wascompletely dissected from the underly-ing bone.

Fig li Complete bone regenerationot the initiol defect was acheived. Thebone immediateiy adjacent to the taf-eial incisor was slightly coronai fo thecontiguous ridge.

Fig Jj The periodontdtly Involved leftlateral incisor has been removed andtwo threaded titdnium implants havebeen placed into the dugmentedridge.

Fig Ik Radiograph taken immediatelyafter implant placement.

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Fig II Histoiogic section throughe-PTFE barrier membrane and underly-ing bone, the newly lormed bone hasasteacyfes within the Idcunae, andosteoblastic octivity is present.

Fig 2a Radiogrdph reveáis extensivebone loss in the mondibuiar left canineand lateral incisar regions.

Fig 2b Photograph taken immedidtely after removal of the periodantatly involvedright taterdi incisor reveals on extensive osseous defect adjacent to the left premo-lar There is insufficient bane to support implants

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Fig 2c (left) Resorbable pins oreplaced inta the recipient sites, extend-ing S mm catana! to Ihe delect base.to provide a tenting effect tor the aug-mentation material and prevent dis-piaoemenf ot the material into thedefect

Fig 2d (right) A large piece of Gare-Tex augmentation moteriai has beendrapea aver the pins ond defect

Flg2e (left) One-week postsurgicalview.

Eg 21 (fight) Ten-month postsurgioaiview. There is communication betweenthe arat cavity and the underlyingmateriol. The potient hos appliedPeridex to the area far the preceding 6manths

Fig 2g Rodlogtophs taken ot time ofmembrane removai ond impiontplocement Note complete bone tot-motion of initial detect.

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Fig 2h (left) Buccoilnguol Hops arereflected, exposing the underlyingaugmentation material.

Fig 21 ((ighf) 7here has been com-plete bone regenerotian with sufficientöone dirnenslan for placement of anendosseaus implant

Fig 2j (leff) Twa endosseous implantsare placed in the restored ridge.

Fig 2k (right) Photograph takeh atsecond-stage surgery, 4 months afterimploht placement. Note bone odjo-oent fo file imptont in the left conineregion.

Fig 21 Radiagraph taken after abut-ment connection.

Fig 2m Implants have been loaded with a provisionoi resroratian.

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Fig 3a fíodiogrophofbtodeimplonf.which wos in ptooe for 9 yeors. Nofeextensive bone loss odjocenf foimplont.

Fig 3b The edentulous ridge is norrow with insufficient bane in an apicoooronoldimension. Resorbobte pins ore shoped to farm a staple and ore ploced into therecipient sifes. Ta sfimulote bleeding, the bone is perforated wUh o smoll round bur.

Fig 3c (left) The augmentafion mate-rial is droped over the support pins.

Fig 3d (righf) The flops are sutured.but complete closure is not achieved.

Fig3e (left) The maferiol becomeexposed ond was removed 7 weeksoffer plocement At this time fhe pinswere not complefely resorbed ondwere removed.

fig 3f (rigtif) fiadiagrdph taken 5months after the augmenfotion proce-dure.

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Fig 3g (left) Bucooiinguol flaps havebeen reflected, exposing the widenedolveotar ridge with an apparentincrease in bone height

Fig 3h (fight) A small trephine is usedto remove a sample of bone for histo-logie evaluation.

Fig 3i Two endosseous impldnts are placed in ideol positions in the regenerated

bone.

Fig 31 The histologie specimen reveáismature bone in the apical half of thesample and woven-type bone in thecoronal halt of the section, indicatingthe presence ot new bone tormdtion.

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Discussion

The objective of this piiot studywas to attempt a new, effec-tive surgical technique foriocaiized ridge bone augmen-totion. The patients In this studyinitiaiiy had bone defects that,because of insufficient bonevoiume. made implant place-ment unrediistic. The resuitsfrom tredtment indicate thatuse of absarbabie pins to sup-port Gore-Tex augmentationmaterial wili create sufficientspace to retain a stabilizedblood oiot, if the membraneremains immobiiized, the ciotshould become organized bybone. The importance of ciotstabiiization for proper woundheaiing has been substanti-ated by Wikesjo ond oawori<-ers.'^The resorbabie orthope-dic pins are on ideal materialto support barrier membraneswhiie creating sufficient spacefor ciot retention. At the time otimplant placement, there wasno ciinicai or radiographiesigns of residual pin remnonts.Unfortunateiy, because of thevariation of defect sizes, it wasnot possibie to accuratelymeasure changes within thedefects. iHowever, radiograph-ie and ciinicai photographicdocumentation cleariy indi-cate the magnitude of boneformed with this teohnique.

Clinicaily, the initial resuitsof this piiot study comparefavorably with those reportedby Buser and coworkers," whotreated edentulous ridges defi-cient in bone width due totraumatic injuries using stainlesssteei mini screws, which actedas tent poles to support e-PTFEaugmentation material. Coila-gen Fieece (Pentapharm AG)was used to stabilize the bloodciot ond to help maintain thespace beneath the mem-branes, in two patients thematerial became exposed andwas removed prematureiy, inour study the materiai becameexposed in two out of threepatients. The sites in which thematerial became exposeddemonstrated campiete heai-ing of the bony defects,Simiiariy. the one defect inwhich the materiai was re-tained for 11 months alsodemonstrated compiete boneregeneration.

Buser et al '* recentiy pub-iished the resuits of treatingmaxiilary anterior ridge defor-mities with speciai screws andmembrane supporting struts.The ciinicai results were excei-ient and impiants were placedinto the augmented ridges atthe time of membrane re-movai. Coliagen Eieece wasaiso used in this documentedseries of treated patients.

Nevins and Meiionigi7reported on three patients withtraumatized edentulous ridgeswith insufficient aiveoiar boneremaining in which to placeimplants. The defects weredebrided and grafted withmineraiized freeze-dried boneaiiogratts and augmented withe-PTFE material. After time inter-vais ranging from 2 to 6 weeks,the membranes becameexposed and were removed.At ó months the ridges weresurgically exposed and the pre-viously treated defects hadapparently resoived. Endos-seous impiants were placed inthe repaired ridges and uiti-mateiy were restored andloaded. The results achieved inour piiot study indicate thotmaintenance ot the spoce be-neath the membrane and astabilized biood ciot are suffici-ent to promote bone formationwithout the use of impiantedmateriais.

The principie of guided tis-sue regeneration has beenappiied to iocaiized ridge aug-mentation without the use ofgrafting materiais. The poten-tial of properly piaced resorb-abie pins to maintain thespace beneath e-PTEE aug-mentatian materiais shouid beinvestigated further.

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References

l.Nymon S, Gottlow J. Lihdhe J,Korring T, Wennstrom J. Newattaohment tormation by guidedtissue regeneratiori. J Periodoht lies1987:3:252-254.

2. Becker W. Becker B. Berg L, PriahardJ, Caffesse R, Rosenberg E. Newattaahment after treatment wittiroot isolation prooedures: Report fortreoted Class III and Class II furca-tions and vertical osseaus defectsInt J Periodont Rest Dent1988;8C3):9-23,

3. Schollhorn R, MoCloin P. Combinedosseous composite gtotting, rootconditianing. ohd guided tissueregeneration. Int J Periodont RestDent 1988;6(d):9-31

4. McGuire MK. Reconstruction ofbohe on faoial surfaces. A series ofcase reports. Int J Periodorit RestDent 1992,12:133-143.

5. Dahlin C, Linde A, Gottlow J.Nyman S. Healing of bone defectsby guided tissue regeneration. PlastReconstrSurg 1989,'81 672-676.

6. Dahlin C, Sennerby L, Lekholm U,Linde A, Nyman S. Generation ofnew bone around titanium implantsusing a membrane technique: Anexpefimental study in rabbits, Int JOral Maxillofac Implants 1989;4:19-25.

7. Becker W, Beoker BE, HondelsmanM, Octisenbein C, Albfektssoh TGuided tissue regenerotion forimplants plciced into extractionsoakets: A study in dogs. J Peria-dontol 1991,62:703-709

6. l.azzara R, Immediate implantplacement into extraction sites'Surgical and restorotive advan-tages. Int J Periodont Rest Dent1989j9:333-343.

9, Becker W, Becker B. Guided tissueregeneration for implants placedinto e>rtfaction sockets and implantdehiscences: Surgical techniquesand case reports. Int J PeriodcntRest Dent 1990,10:377-391,

10. Seibert J, Nyman S. Localized ridgeaugmentation in dogs: A pilot studyusing membranes and hydroxy-apatite. J Periodontol 1990;61:157-165.

11,Buser D, Bragger U, Lang NP,Nyman S. Regeneration andenlargement of jaw bone usingguided tissue regeneration. ClinOrallmplResl990:l:22-32.

12. Simion M, Baldoni M, Zatfe DJawbane enlargement using imme-diate implant placement assaci-oted with a split-crest techniqueond guided tissue regeneration. IniJ Periodont Rest Dent 1992:12:463-473.

13. Shanaman RH. The use of guidedtissue regeneratiah to facilitateideal prosthetic placement ofimplants. Int J Pedodont Rest Dent1992; 12:256-205.

14 Aden R, Lekholm U. Surgical proce-dures. In: Branemark P-l, Zarb GA,Albrektsson T (eds). Tissue-Inte-grated Prostheses: Ossecintegrationin Clinical Dentistry. Chicago'Quintessence, 1985:211-232,

15. Wikesjo UME, Claftey N, Egelberg J.Periodontal repair in dogs. Effect ofheparjn treatment of the root sur-faces. J Clin Periodontol 1991 ; 18:60.

1Ó. Buser D, Dula K, Belser U, Hirt HP,Berthold H. Localized ridge aug-mentation using guided bonerégénération I Surgical procedurein the maxilla. Int J Pericdont RestDent 1993:13.29-45.

17. Nevins M, Mellcnig J. Enhancementof the damaged edentulous ridgeto receive dental implants A com-binatian ot allograft ohd the Gore-Tex Membrane. Int J Periodcni RestDent 1992,2-97-111

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