Izchak Barzilay, DDS*/Gerald N. Graser, DDS, MS**/Bejan Iranpour, DDS, MS***/Joseph R. Natiella, 005***

The conventional osseointegration protocol calls for waiting up to 12 months forossification of an extraction socket to heal before placing an endosseous implant. In thisstudy the possibility of placing a pure titanium implant directly into an extraction socketimmediately after extraction was investigated. A pure titanium Nobelpharma 10-mmimplant was placed into a central incisor extraction socket of a stump-tailed monkey andallowed to heal for a period of 6 months, followed by functional loading of the implant.The implant was osseointegrated on a clinical and histological level. This pilot studysuggests that pure titanium implants have the potential to integrate when placedimmediately after extraction of the teeth and warrants further investigation.(INT J ORAL MAXlLLOFAC IMPLANTS 1991;6:277-284.)

Key words: endosseous titanium implant, immediate implantation, osseointegration

T he long-term success of osseointegrated implantsusing principles outlined by Branemark is well es-

tablished and has been well documented.l~3 The Bra-nemark (Nobelpharma USA, Inc, Chicago, Ill) implantis a pure titanium threaded cylinder that is inserted intothe jaw using precise and atraumatic surgical tech-niques. These implants (fixtures) are then allowed to

heal for a period of 4 to 6 months while covered by amucoperiosteal flap with no oral communication. Theyare then uncovered and placed in function with a spe-cially designed prosthesis. The system was originallyused to rehabilitate the completely edentulous pa-tient, but subsequently has been modified for the par-tially edentulous patient and craniofacial prostheticreconstruction.

One of the requisites for successful osseointegrationhas been to allow ossification of natural tooth extractionsockets before the placement of implants. -I A patient

would then wait up to 12 months for an extractionsocket to ossify before the implant was placed.5 Thistime interval is considered necessary for proper boneformation and maturation postextraction.6 Followingbone healing, the patient then undergoes two surgicalprocedures; first, the placement of the fixture, and sec-ond, the attachment of the abutment. The delay duringsocket healing, coupled with the added surgical stage,is inconvenient as well as disconcerting and uncom-fortable to the patient, who may already be havingdifficulty wearing a conventional removable prosthesis.

As there is no applicable method to expedite alveolarossification, there is clearly a need to determinewhether immediate implantation of a titanium implant

'Private Practice, Toronto, Ontario, Canada; Research Associate,Department of Prosthodontics, Eastman Dental Center, Roch-

ester, New York; Associate in Dentistry, University of Toronto,Toronto, Ontario; Head, Division of Prosthodontics, Mt. Sinai

Hospital, Toronto, Ontario.. 'Chairman, Department of Prosthodontics, Senior Clinician, Se-

nior Research Associate, Eastman Dental Center; Associate Pro-

fessor, Department of Dental Research, University of Rochester,Rochester, New York.

"'Senior Clinical Associate, Eastman Dental Center; Chief, De-partmentofDentistry, The Genesee HosPital; Associate Professor,Department of Dental Research, University of Rochester, Roch-

ester, New York.""Professor, Department of Stomatology and Interdisciplinary Sci-

ences, School of Dental Medicine, State University of New Yorkat Buffalo, Buffalo, New York.

Correspondence to: Dr I. Barzilay, 2300 range Street, Suite 905Box 2334, Toronto, Ontario, M4P 1£4.

into a fresh extraction socket can succeed when thealveolus is mechanically modified upon removal of thetooth. The modification resembles the preparationmade for placement of an implant in an ossified alveolarstructure.

Success of this procedure would have the following

advantages:1. The elimination of waiting many months for ossi-

fication of the socket2. Possible maintenance of alveolar bone height and

width3. Fewer surgical procedures4. Shortened edentulous time period

Literature Review

that can be used in either immediate postextractionimplantation or in the healed bone of an edentulousjaw. The author claims to achieve an integrated fixa-tion, yet the scientific methodology and experimentaldesign used to determine this success are not described.

Anneroth et al14 placed pure titanium screw-shapedfixtures (Xenodent) into the mandibular incisor extrac-tion sockets of four monkeys immediately after extrac-tion. The procedures followed the surgical protocol pro-posed by Branemark, and the implants were evaluatedat 7 and 12 weeks postinsertion. The investigators de-scribe a "normal" appearing bone/implant interfacewith no inflammation. Bone is shown in close appo-sition to the implant, yet there is still connective tissuepresent between the bone and the implant surface. Theimplants appeared healthy at 12 weeks but were notplaced in occlusion; therefore, any evaluation of func-tion could not be made.

Todescan et al15 recently evaluated cobalt-chromiumimplants in molar extraction sites of mice. This workused a small-animal model, and several materialswere employed to expedite bone healing around animplant placed immediately after tooth extraction.Whereas the findings are useful, the small-animalmodel does not easily lend itself to the evaluation ofimplants under functional load, which is important forassessment of the functional capability of osseointe-

grated implants.Recent publications advocate the use of nonresorb-

able barrier techniques to aid in the healing of implantsplaced into extraction sockets. 16.17 These case reports,

however, show little histologic data to support claimsof bone fill. Becker et aIls recently reported on the useof Gore- Tex augmentation material (WL Gore & As-soc, Flagstaff, Ariz) around immediate implants indogs. The study reported on the efficacy of healingdehiscences using a barrier versus not using a barrier.Their study showed that the barrier significantly en-hanced bone formation at extraction sites when dehis-cences were involved.

Confirmation of immediate implantation as a suc-cessful clinical technique cannot be drawn from thesestudies. In order for an implant to be evaluated forimmediate implantation, it should be placed atrau-matically, allowed to heal undisturbed, and function-ally loaded. In this manner, true clinical conditionsare implemented in the experimental design. This pa-per reports on a preliminary study that evaluated im-mediate implantation of a pure titanium implant intoa fresh extraction socket.

Materials and Methods

One elderly stump-tailed monkey had its mandibularleft central incisor and right lateral incisor extracted.

Investigators have attempted to place implants directlyinto extraction sockets, but many of these attempts havemet with failtKe.

Samachiaro and Gargantini7 placed four titaniumblade-vent implants in four Caraya monkeys immedi-ately after extraction of mandibular second and thirdpremolars and first molars. The implants were evalu-ated histologically 60 days after placement and werefound to be encased in a peri-implant membrane of

connective tissue,Weiss and Rostoker8 evaluated fiber titanium im-

plants in mongrel dogs. Seventy-eight implants wereplaced into molar extraction sockets and studied forperiods ranging from 1 week to 1 year. This study had11 failures, and electron probe studies confirmed thatthere was always an interface of fibrous tissue 5 to 50fJ,m thick between bone and metal. These implantswere allowed to heal while exposed to the oral cavityand were not put into direct function.

Porous vitreous carbon polymethacrylate replica im-plants were inserted into the extraction sockets of 12baboons by Hodosh et al.9 Their histological studiesshowed a peri-implant membrane composed of colla-gen fiber bundles and numerous inflammatory cells.The presence of peri-implant connective tissue (fi-brous) is considered by many to be a sign of eventualfailure, 3,10,11

Karagianes et allz placed 13 porous titanium alloyimplants into molar and premolar extraction sockets ofMacaca nemestrina immediately following tooth ex-traction. The fixtures were left in place for 6 weeks afterinsertion and loaded with a functional fixed prosthesis.Of the 13 implants, 8 had failed, with rejection timesvarying from 3 to 29 months. The investigators sug-gested that the high failure rate was enhanced by pooranimal health, poor bone configuration, and poor sur-

gical technique.Schulte13 claimed success over 8 years using the Tii-

bingen implant. This is an intraosseous AlzO3 implant

Fig 1 The extraction socket tapped (threaded) with the No-belpharma titanium screw tap.

Fig 2 The composite resin gold crown has been secured inposition with the conventional gold screw. Occlusion of thecrown has been verified.

6. Pocket depth; Ramfjord247. Gingival margin location; Ram~ord248. Attachment level; Ramfjord249. Gingival width; Ramfjord24

10. Occlusion and prosthesis conditionMeasurements were made with a standard Glickman

probe (no. 26 G) at a point midsurface on the buccal,lingual, mesial, and distal surfaces. The precise pointwas marked by a dimple cut into the gold coping andwas visible to the examiner.

Radiographic Assessment. Radiographic examina-tion took place at the time of crown placement andagain 6 months postloading. Radiography of the peri-fixtural structures at crown placement and at the endof the observation period (12 months postimplantation)was performed using the long cone paralleling tech-nique. For the purposes of comparing standardized ra-diographs, a jig was fabricated so that film placementwould be duplicated at these two time points.

A square impression coping was attached to the lab-oratory analogue on the master cast and luted withautocure resin to a radiographic film holder. The filmholder was positioned so that once in place in themouth, the film and implant were parallel to eachother. A 16-inch long cone paralleling technique ringwas then attached to the film holder and a radiographwas made (70 Kv, 15 mA, 1/2 sec). A second ring,angulated at 12° in the horizontal direction, was thenused to allow the making of a second radiograph witha central ray angulated 12° to the first radiograph. Thetwo-film procedure (stereo roentgenography) is helpfulin obtaining the following data:1. Marginal bone height (mesially and distally), using

the fixture threads as an internal dimensionalreference

2. Possible presence of radiographically detectable softtissue at the bone / fixture interface

The alveolar walls were curreted vigorously to removethe residual pe'riodontalligament. Using the sequenceof drills commonly used in the Branemark procedure, 1

the left central incisor socket was prepared (Fig 1) anda lO-mm pure titanium Branemark fixture was insertedand appeared to have good stability. Preparation of thesocket involved enlarging the socket's diameter as wellas deepening to accommodate the implant. At the timeof placement, it was noted that the superior 2 to 3 mmof the socket was wider and the inferior 5 to 6 mm wasnarrower than the implant. The apical 2 to 3 mm ofthe implant extended beyond the apex of the socket.The socket of the right lateral incisor was allowed toheal without intervention to assess the length of timeneeded for extraction socket healing. The implant wassealed with a conventional cover screw, and both siteswere covered with a wide-banded mucoperiosteal flapmobilized to seal the cover screw and allowed to heal.

After a healing period of 6 months, a transmucosalabutment was connected to the implant. Prosthodonticprocedures (impressions, jaw registrations) were com-pleted and a 4 methacryloxyethyl trimellitate anhydride(4-META) light-cured, composite resin gold crown wasfabricated and attached to the implant with the con-ventional prosthodontic components of the Branemarksystem (Fig 2). The crown/implant assembly func-tioned in occlusion for 6 months.

Clinical Assessment. During the 6-month loadingperiod, clinical measurements were made every 2months. The clinical assessment consisted of the fol-lowing parameters:

1. Visual signs of inflammation; Meitner et al(modified)19

2. Plaque accumulation; Silness and Loe203. Mobility; Lindhe and Nyman (modified)214. Pocket bleeding index; Proye et aJ225. Sulcus bleeding index; Muhlemann and Son23

The type of tissue present at the interface was quan-tified and characterized into three groups using thecomputerized digital analyses system. The three groupswere:I. Direct bone contact2. Bone marrow contact3. Fibrous soft tissue contactThese three types of tissue are important in that theyare all present to some degree in implant systems.

Ground Section. The implant block for ground sec-tion was embedded in methyl methacrylate and thensectioned horizontally using the Bueler Isomet (BuehlerLtd, Lake Bluff, III) slow-sectioning machine. Thespecimen was then glued to a glass slide with epoxyresin adhesive and petrographically ground to reducethe thickness of the specimen to 30 to 50 ~m. Thespecimen was then stained using a Villanueva stain.

Ultrastructural Assessment. Ultrastructural evalua-tion using a transmission electron microscope scannedthe periabutment mucosa to determine morphologiccharacteristics and changes within the tissue.

3. Presence of internal mechanical failure of thefixtureZ5

After the functional loading period, the implant,with its surrounding hard and soft tissue, was re-moved en bloc under local anesthesia and evaluatedhistologically.

Histological Assessment. Histological assessmentmade use of four evaluations:1. Gross evaluation2. Decalcified section3. Ground section4. Ultrastructural evaluation

The implant and its surrounding hard and soft tissuewas block-sectioned from the jaw and placed in pitricacid formaldehyde. After fixation, the implant blockwas sectioned longitudinally using the Bueler 1sometslow-speed sectioning machine. One half of the implantwas processed for decalcified section (longitudinal sec-tioning) and.the second half was processed for groundsection (horizontal sectioning). A soft-tissue specimenwas removed from the periabutment mucosa and pro-cessed for ultrastructural evaluation.

Decalcified Section. The implant block was decal-cified using formic acid and sodium citrate. Once de-calcification was complete, the implant was removedfrom the block and thin-sectioning procedures wereinitiated. The crypt surface of the implant was scannedusing a scanning electron microscope to ensure that notissue remnants were present on the surface. The spec-imen was then prepared in paraffin to a thickness of0.75 to 1.5 !-Lm. Hematoxylin and eosin, Masson, andVillanueva stains were used in the evaluation of thevarious sections.

Results

Clinical Assessment. At each clinical examination pe-riod, the implant and a neighboring tooth were ex-amined. No difference was found between the mea-surements recorded on the periabutment tissues of theimplant when compared to a neighboring natural tooth.There was no measurable increase in pocket depth andclinical measurements revealed no loss of attachment.Gingival inflammation was present to the same degreeon both the implant and the natural tooth. No mobility

Fig 3 (Left) Radiograph made at thetime of crown placement. No radiolu-cent area can be seen around the im-plant and bone appears to be abuttingagainst the implant surface.

Fig 4 (Right) Radiograph made afterthe functional loading period. Noticethe 1.3-mm vertical bone loss presenton the mesial surface of the implant.This bone loss may be associated withthe neighboring central incisor's peri-odontal bone loss.

onstrated bone to be in contact with the implant surfacealong most of its length and no inflammatory cells wereseen on the sections evaluated (Fig 5).

Using the computerized digital analysis system, thispilot study found 58.2% of the implant's embeddedlength was in apparent direct contact with bone (theword "apparent" is used because of the fact that theimplant was removed during the thin-sectioning pro-cedure and the implant space was measured rather thanthe implant surface itself); 24.7% of the implant'sembedded length was in contact with bone marrow;and 17. 1 % of the implant's embedded length was incontact with fibrous soft tissue (Fig 6).

Ground Section. The specimens evaluated showed aclose relationship of nutrient canals to the implant sur-face, indicating a healthy and viable relationship be-tween the implant and the host tissue (Fig 7).

or signs of infection were noted at the implant site atany time during the study.

The composite resin crown was still in functionalocclusion at the conclusion of the loading period andheld up well over the duration of the study.

Radiographic Assessment. No radiolucent areacould be seen surrounding the implant at the two timepoints. Of interest was the loss of vertical bone heightseen on the mesial surface of the implant at the con-clusion of the loading period (Figs 3 and 4). This losswas measured at 1.3 mm.

Histological Assessment. Gross Evaluation. Thegross specimen showed a 2-mm soft-tissue pocket sur-rounding the superior aspect of the implant. The re-mainder of the host tissue seemed to be in intimatecontact with the surface of the implant.

Decalcified Section. The evaluated specimens dem-

Fig 5 (Left) Photomicrograph of a de-calcified section of the implant/boneinterface demonstrating bone to be incontact with the implant surface alongmost of its length (hematoxylin and eo-sin, original magnification x 50).

Fig 6 (Right) Photomicrograph of a de-calcified section of the implant/boneinterface showing direct bone contact(B), bone marrow contact (M), and fi-brous soft tissue contact (F). The mor-phological differences are easily seenat this magnification (hematoxylin andeosin, original magnification x 200).

Fig 7 Photomicrograph of a ground section of the implant!bone interface showing a nutrient canal opening into theimplant space (Villanueva stain, original magnificationx200).

preparation, the implant was dislodged. Thus the in-formation given by this technique in this study is oflimited value. The ground section specimen has theadvantage of implant presence on the slide so that theexact implant position can be evaluated. Its disadvan-tage is that for this to be accomplished, the preparedsection must be thicker and the type of soft tissue presentis more difficult to characterize.

The tissue classification devised for this study is im-portant in that a distinction must be made between thetwo types of soft tissue present at the interface. Thesetissues are bone-marrow-associated soft tissue, whichin fact may become ossified in the future, and fibroussoft tissue, which is a scarlike soft tissue. In reportingdata, the soft-tissue component is generally presentedas a single tissue and compared to the calcified sup-porting bone. It is reported in this manner because thedense calcified bone at the interface gives the implantits immediate physical support. Thought must also begiven to the role played by the bone marrow soft tissuein providing nutrients and support for the dense sup-porting bone at the interface. This being the case, thereis a need for a more exact classification of the soft tissuetype at the implant/host-tissue interface.

There may have been a presumption that osseoin-tegration would imply that the entire surface of theimplant is interfaced with bone (calcified matrix).29 Inimmediate implantation, a 100% calcified bone/im-plant interface does not appear to occur, yet there isclinical stability of the implant. In the literature, in-terface ratios of 50% to 80% have been reported forbone contact with an implant. 30-32 The minimum per-

centage of integration has yet to be defined for clinicalsuccess.

Fig 8 Transmission electron micrograph of the periabut-ment mucosa showing an epithelial cell with numerous des-mosomes (0) and hemidesmosomes (H) (original magnifi-cation x 6500).

Ultrastructural Evaluation. Ultrastructural evalua-tion using a transmission electron microscope scannedthe periabutment mucosa and showed an active basallamina and normal capillaries. Epithelial cells appearedto be keratinized normally, and desmosomes and hemi-desmosomes were evident in the intercellular regions(Fig 8). In examining the deeper crevicular tissues,degenerative changes were noted in the cellular com-ponents. The actual abutment/soft-tissue interfacecould not be delineated in the preparation.

Discussion

Conclusions

Pure titanium implants placed immediately after ex-traction of teeth in monkeys have the potential to os-seointegrate. One hundred percent osseointegrationmay not occur and may not be needed along the entireimplant/bone interface for successful and predictablefunction. Osseointegration may not be an all-or-nonephenomenon and may rather be a clinical term ratherthan a histological term. There is a need to make thedistinction between the type of soft tissue present at theimplant interface.

The results of this pilot study indicate that immediateimplant placement into fresh extraction sockets is apotentially viable technique and certainly warrants fur-ther investigation. A more in-depth study has been ini-tiated that will evaluate this technique and compare itto the conventional technique of placing implants intohealed bone. 0

Clinical measurements revealed no difference betweenthe implant and a neighboring tooth. The fixed res-toration placed on the implant survived well. For astudy of this duration, it would seem that this type ofrestoration would serve the study adequately.

In evaluating the radiographs, a 1..3-mm vertical lossof bone was noted on the mesial surface of the implant.This is within the limit suggested by Adell et al.l Inevaluating implant bone loss, some of this loss couldbe caused by the periodontal breakdown of the toothnext to the implant (right central incisor). Should thisbe factual, special attention must be given implantsplaced next to natural teeth that are periodontally in-volved or in patients who are prone to periodontal dis-ease. This bone loss was also not detected using theperiodontal probe because the soft tissue present at thegingival cuff was in close apposition to the threads ofthe implant. This finding casts some doubt on the ef-ficacy of the periodontal probe as a measuring devicefor peri-implant pockets and is in agreement with thework of other investigators. 3.26-28

Technical difficulties were encountered during prep-aration of the specimen for ground section. During

Acknowledgments

The authors would like to thank Dr J. Caton, DDS, MS, for hiscontinued guidance and assistance. 'l'lle authors also sincerelyacknowledge the support of Nobelphamla Inc, Greater New YorkAcademy of Prosthodontics Foundation, Education and ResearchFoundation of Prosthodontics, Eashnan Dental Center Prosthodon"tic Research Fund, and Biomedical Research Support GralltRR5548.

References

I. Adell R, Lekholm U, Rockier B, et al: A I; year study ofosseointegrated implants in the treatlnent of the edentulousjaw. Int T Oral Surg 1981;6:387-416.

2. Branemark P-I, Zarb GA, Albrektsson T (eds): Tissue-Integrated Prostheses: Osseointegration in Clinical Dentistry.Chicago: Quintessence Publ Co, )98;.

3. Albrektsson T, Zarb GA, Worthington P, Eriksson AR: Thelong-ternl efficacy of currently used dental implants: A reviewand propose~ criteria of success. IntT Oral Maxillofac

Implants 1986;1:11-2;.4. Ohmell LO, Hirsch JM, Ericsson I, Br~nemark P-I: Single

tooth rehabilitation using osseointegration. A modifiedsurgical and prosthodontic approach. Quintessenf!e Int1988;19:871-876.

5. Br~nemark P-I: Personal communication, 1986.6. Schulman LB: Surgical considerations in implant dentistry.

T Dent Educ 1988;52:712-720.7. Samachiaro 0, Gargantini LC: Biological tissue reaction to

immediate post extraction blade implants. Implantol

1979;1:44-51.8. Weiss MB, Rostoker W: Development of a new endosseous

dental implant. Part II: Human studies. T Pros~t Dent

1982;47:633-645.9. Hodosh M, Povar M, Shklar G: The porous vitreous carbon-

polymethacrylate replica implant. Continuing studies.T Prosthet Dent 1979;42:557-565.

10. Lavelle CLB, Wedgewood D, Love WB: Some advances in

endosseous implants. T Oral RehabiI1981;8:319-331.II. Brunski JB: The influence of force, motion and related

quantities on the response of bone to implants, in FitzgeraldRH (ed): Non-cemented Total Hip Arthroplasty. New York:Raven Press, 1988, pp 7-22. .

12. Karagianes MT, Westerman RE, Hamilton'AI, et al:Investigation of long-term performance of porous metal dental

implants in nonhuman primates. T Oral Implantol1982;10:189-208.

13. Schulte W: The intra-osseous AlzOJ (Frialit') Tuebingenimplant. Developmental status after eight years. I.

Quintessence Int 1984;15:9-26.14. Anneroth G, Hedstrom KG, Kiellman 0, Kondell PA,

Norderam A: Endosseous titanium implants in extractionsockets: An experimental study in monkeys. Int T Ora/. Surg

1985;14:50-54.15. Todescan R, Pilliar RM, Melcher AH: A small animal model

for investigating endosseous dental implants: Effect of graft

materials on healing of endosseous, porous-surfaced implants

placed in a fresh extraction socket. Int 1 Oral Maxi/lofac

Implants 1987;2:217-223.16. Lazzara RJ: Immediate implant placement into extraction

sockets: Surgical and restorative advantages. Int 1 Periodont

Rest Dent 1989;9:333-343.17. Nyman S, Lange NP, Busel D, Bragger U: Bone regeneration

adjacent to titanium dental implants using guided tissueregeneration: A report of two cases. Int 1 Oral Maxi/lofac

Implants 1990;5:9-14.18. Becker W, Becker BE, Ochsenbein C, Handelsman M,

Cellete R: The use of guided tissue regeneration for implantsplaced in immediate extraction sockets. Abstract presented at2nd International Congress on Tissue Integration in Oral,

Orthopedic, and Maxillofacial Reconstruction, Rochester,Minn, September 1990.

19. Meitner S, Zander HA, Iker HP, Polson AM: Identification ofinflamed gingival surfaces. 1 Clin Periodontol 1979;6:93-97.

20. Silness J, Loe H: Periodontal disease in pregnancy. II.Correlation between oral hygiene and periodontal conditions.Acta Odontol Scand 1964;22:121-135.

21. Lindhe J, Nyman S: The effect of plaque control and surgicalpocket elimination on the establishment and maintenance ofperiodontal health. A longitudinal study of periodontaltherapy in cases of advanced disease. 1 Clin Periodontol

1975;2:67-79. "22. Proye M, Caton JG, Polson A: Initial healing of periodontal

pockets after a single episode of root planing monitored bycontrolled probing forces. 1 PeriodontoI1982;53:296-301.

23. Muhlemann HR, Son S: Gingival sulcus bleeding: A leadingsymptom in initial gingivitis. Helv Odontol Acta 1971;15:107-

113.24. Ramfjord S: The periodontal disease index (PDI).

1 Periodontol 1967;38:602-610.25. Hollender L, RockIer B: Radiographic evaluation of

osseointegrated implants of the jaw. Dentomaxi/lofac Radiol

1980;9:91-95.26. Apse P, Zarb GA, Schmitt A, Lewis DW: The longitudinal

effectiveness of osseointegrated dental implants: The TorontoStudy: Peri-implant mucosal response. Int 1 Periodont Rest

Dent 1991;2:95-111.27. Cox JF: The longitudinal clinical efficacy of osseointegrated

implants. Thesis. Toronto: University of Toronto, Faculty ofDentistry, Department of Prosthodontics, 1983.

28. Deporter DA, Friedland B, Watson PA, et al: A clinical andradiographic assessment of a porous-surfaced, titanium alloydental implant system in dogs. 1 Dent Res 1986;65:1071-1077.

29. Boyner PI: Osteo-Integration. Paper presented at the AmericanAcademy of Implant Dentistry: Research FoundationSymposium II, Palm Springs, Calif, April 1988.

30. Block MS, Kent IN, Finger 1M, Mohr G: Loaded HA-coatedand grit titanium implants in dogs. IADR abstract no. 523.1 Dent Res 1988;67(special issue): 178.

31. Neary J, Block MS, Rankine C: A comparison of osseousresponse to orthodontic loading of HA coated and non-coatedimplants. IADR Abstract no. 524. 1 Dent Res 1988;67(special

issue): 178.32. Brunski JB: Biomechanics of oral implants: Future research

directions. 1 Dent Educ 1988;52:775-787.

ResumeImplantation immediate d'un implant detitane pur au sein d'un site d'extraction:Rapport d'une technique pilote

le protocole d'osteointegration traditionnelrequiert d'attendre jusqu'a douze moisI'ossification d'une alveole apres extractionavant de placer un implant endoste. Danscette etude, on a evalue la possibilite deplacer un implant de titane pur directementdans I'alveole et immediatement apresextraction. Un implant de titane pur de 10mm fut place dans I'alveole d'une incisivecentrale de singe et apres une periode deguerison de six mois, fut place en charge.l'implant etait osteointegre d'un point devue clinique et histologique. Cette etudepilote suggere que les implants de titanepur ant Ie potentiel de s'integrer au tissuosseux lorsqu'ils sont placesimmediatement apres extraction dentaire etcette propriete merite d'etre etudiee.

ZusammenfassungImmediatimplantation eines Implantatesaus rein em Titan in ein Extraktionszahnfach:Bericht van einem Pilotverfahren

Nach dem konventionellenOsseointegrationsprotokoll 5011 man bis zu12 Monaten darauf warten, da(3 Ossifikationeines Extraktionszahnfaches heilt, bevorman ein enossales Implantat einsetzt. Inder vorliegenden Studie wurde dieMoglichkeit untersucht, ein Implantat ausreinem Titan direkt in einExtraktionszahnfach sofort nach Extraktioneinzusetzen. Ein Nobelpharma-lmplantat,aus reinem Titan und van 10 mm lange,wurde in das Extraktionszahnfach einesmittleren Schneidezahns einesstummelschwanzigen Affen eingesetzt undhatte eine sechsmonatige Einheilphase;darauf folgte funtionelle Belastung desImplantates. Das Implantat wurde klinischund histologisch osseointegriert. Dievorliegende Pilotstudie la(3t daraufschlie(3en, da(3 Implantate aus reinem TitanIntegrationspotential haben, wenn siesofort nach Extraktion der Zahne eingesetztwerden. Weitere Untersuchungen uberdieses Verfahren sollten gemacht werden.

ResumenReporte de un procedimiento pilato sabre/a c%caci6n inmediata de un imp/ante detitanio puro en un a/ve% inmediatamentedespues de /a exodoncia

EI protocolo convencional de laoseointegraci6n aconseja esperar hastadace meses para dar paso a la osificaci6nde un alveolo despues de la exodoncia,antes de colocar un implante end6seo. Eneste estudio se investig6 la posibilidad decolocar un implante de titanio purodirectamente en el alveolo,inmediatamente despues de la extracci6ndental. Se coloc6 un implante de titaniopuro, de 10 mm, de la casa Nobelpharmaen el alveolo que correspond fa a unincisivo central de un mono de cola carta.luego de un periodo de cicatrizaci6n deseis meses el implante fue puesto enfunci6n. EI implante se oseointegr6 deacuerdo al analisis clfnico y al histol6gico.Este estudio pilato indica que IDS implantesde titanio puro tienen el potencial deintegrarse cuando son colocadosinmediatamente despues de la extracci6nde IDs dientes, 10 cual justifica la necesidadde efectuar investigaciones adicionales.