treatment of ligature-induced peri-implantitis by lethal...

Volume 74 • Number 3

338

Treatment of Ligature-Induced Peri-Implantitis by LethalPhotosensitization and GuidedBone Regeneration: A Preliminary Histologic Study in DogsJamil Awad Shibli,*† Marilia Compagnoni Martins,* Francisco Humberto Nociti Jr.,‡Valdir Gouveia Garcia,§ and Elcio Marcantonio Jr.*

Background: The purpose of this pilot study was to evaluatethe healing potential and reosseointegration in ligature-inducedperi-implantitis defects adjacent to various dental implant sur-faces following lethal photosensitization.

Methods: A total of 36 dental implants with 4 different sur-face coatings (9 commercially pure titanium surface [CPTi]; 9titanium plasma-sprayed [TPS]; 9 hydroxyapatite [HA]; and 9acid-etched [AE]) were inserted in 6 male mongrel dogs 3months after extraction of mandibular premolars. After a 2-monthperiod of ligature-induced peri-implantitis and 12 months ofnatural peri-implantitis progression, only 19 dental implantsremained. The dogs underwent surgical debridement of theremaining dental implant sites and lethal photosensitization bycombination of toluidine blue O (100 µg/ml) and irradiation withdiode laser. All exposed dental implant surfaces and bone craterswere meticulously cleaned by mechanical means, submitted tophotodynamic therapy, and guided bone regeneration (GBR)using expanded polytetrafluoroethylene (ePTFE) membranes.Five months later, biopsies of the implant sites were dissectedand prepared for ground sectioning and analysis.

Results: The percentage of bone fill was HA: 48.28 ± 15.00;TPS: 39.54 ± 12.34; AE: 26.88 ± 22.16; and CPTi: 26.70 ± 16.50.The percentage of reosseointegration was TPS: 25.25 ± 11.96;CPTi: 24.91 ± 17.78; AE: 17.30 ± 15.41; and HA: 15.83 ± 9.64.

Conclusion: These data suggest that lethal photosensitiza-tion may have potential in the treatment of peri-implantitis. J Peri-odontol 2003;74:338-345.

KEY WORDSAnimal studies; dental implants; guided bone regeneration;osseointegration; peri-implant diseases/therapy;photochemotherapy; photosensitizing agents.

* Department of Periodontology, Dental School of Araraquara, State University of São Paulo,Araraquara, SP, Brazil.

† Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY.‡ Department of Periodontology, Dental School of Piracicaba, University of Campinas, SP,

Brazil.§ Department of Periodontology, Dental School of Araçatuba, State University of São Paulo,

Araçatuba, SP, Brazil.

Several animal experiments have shownthat bacterial biofilm accumulationaround dental implants promoted by

ligature placement can result in peri-implanttissue breakdown or peri-implantitis.1-4

Although there are difficulties in attemptingreosseointegration on dental implant sur-faces after contamination by periodontalpathogens such as Actinobacillus actino-mycetemcomitans, Prevotella intermedia,Porphyromonas gingivalis, Bacteroidesforsythus, and Fusobacterium nucleatum,several therapeutic strategies have been usedto treat peri-implantitis,2,5-8 including decon-tamination with mechanical,3,4,8 chemical,2,5

and physical6,9 methods.The physical method utilizes a low-power

laser following application of a photosensi-tizing substance. Toluidine blue O (TBO)(see reference 10 for review) has been uti-lized in both periodontal11-16 and peri-implant diseases.6,17 The mechanism bywhich TBO kills microorganisms such asP. gingivalis, P. intermedia, A. actino-mycetemcomitans, and F. nucleatum hasnot yet been established, but it is believedthat lethal photosensitization of thesemicroorganisms may involve changes in themembranes and/or plasma membrane pro-teins and DNA damage mediated by singletoxygen.15,18,19

The objective of this pilot study was toreport the results of a prospective studyon lethal photosensitization on ligature-

2083_IPC_AAP_553033 3/7/03 12:05 PM Page 338

J Periodontol • March 2003 Shibli, Martins, Nociti, Garcia, Marcantonio

339

induced peri-implantitis in dogs with different dentalimplant surfaces.

MATERIALS AND METHODSAnimalsThe experiment outline is shown in Figure 1. Six adult,systemically healthy, male mongrel dogs, 2 years ofage, with an average weight of 18 kg were used. Ani-mal selection, management, and surgical protocol fol-lowed routines approved for this study by the DentalSchool of Araraquara Institutional Animal Care andUse Committee.

All surgical and clinical procedures as well as thelaser irradiation were performed under general anes-thesia accomplished by 0.05 mg/kg of subcutaneouspreanesthesia sedation (atropine sulphate�) and intra-venous injection of chlorpromazine¶ and thiopental.#

Oral prophylaxis was performed within 2 weeks oftooth extraction. Mandibular premolars were thenextracted, creating an edentulous ridge. Both themandibular quadrants and the alveoli were allowed toheal for 3 months. The upper premolars were alsoextracted to avoid occlusal trauma interference. Dur-ing the healing period, bacterial biofilm was controlledby daily scrubbing with 0.12% chlorhexidine** andmonthly scaling and root planing until cotton ligatureplacement.

Implant Design and SurfacesThirty-six dental implants with 4 different surfaces from3 implant systems were used as follows: 9 commer-cially pure titanium implants†† (CPTi); 9 titaniumplasma-sprayed‡‡ (TPS); 9 hydroxyapatite§§ (HA); and9 hybrid surfaces: machined titanium in the first 3screws and acid-etched in the other screws� � (AE). Allimplants were 10 mm long with a diameter of 3.75mm (except TPS, which had a 4.1 mm diameter).

Implant SurgeryThe dental implants were placed after the full-thicknessflap under aseptic surgical conditions. The recipientsites were prepared for each implant surface, accord-

ing to the manufacturer instructions. The implants wererandomly distributed so that each dental implant sur-face was placed at least once in each animal. Theimplants were positioned at the bone level and a coverscrew was screwed onto the implant, including the TPSdental implant surface based on a technique modifi-cation indicated by the manufacturer. The flaps weresutured with single interrupted sutures, submerging allimplants.

Antibiotics¶¶ were given once a week for 2 weeksto avoid postsurgical infection. Acetaminophen## wasgiven for pain control medication. The sutures wereremoved after 10 days.

Experimental Peri-ImplantitisThree months after implant placement, healing abut-ment connections were installed, according to manu-facturer instructions. After 2 months of a plaque con-trol program and healing of the soft tissue, cotton flossligatures were placed around the dental implants andsutured in the peri-implant mucosa, not only to facil-itate plaque accumulation, but also to hold the ligaturesin position. Additional ligatures were placed at 20-dayintervals for 60 days to accelerate peri-implant boneloss. At 60 days after first placement, when approxi-mately 40% of the initial bone support was lost, liga-tures were removed.

A 12-month plaque control program was initiated bydaily scrubbing with 0.12% chlorhexidine and scalingthe abutment surface once a month. At the end of thisperiod, natural peri-implantitis progression wasobserved and only 19 dental implants (6 TPS; 5 CPTi;5 AE; and 3 HA) were viable. The other 17 were mobiledue to significant peri-implant bone loss and wereexcluded from our sample.

All dogs were subjected to surgical debridement ofthe dental implant surface and bone craters; lethalphotosensitization; and guided bone regeneration(GBR) of the implant sites.

Lethal Photosensitization and Guided BoneRegenerationA crestal incision was made through the mucosa,and buccal and lingual full-thickness flaps were ele-vated (Fig. 2A). The abutments were removed, andthe granulation tissue present in bone craters aroundthe dental implants was curetted with a plastic curet(Fig. 2B).

� Ariston Inds. Química e Farms. Ltda, São Paulo, Brazil.¶ Amplictil, Rhodia Farma Ltda, São Paulo, Brazil.# Abbott Laboratórios do Brasil Ltda, São Paulo, Brazil.** Pharmacy School, State University of São Paulo, Araraquara, SP, Brazil.†† 3i Implant Innovations, Inc., Palm Beach Gardens, FL.‡‡ Esthetic plus ITI, Straumann AG, Waldenburg, Switzerland.§§ Calcitek, Centerpulse Dental, Carlsbad, CA.� � Osseotite, 3i Implant Innovations, Inc.¶¶ Fort Dodge Saúde Animal Ltda, Campinas, SP, Brazil.## Paracetamol, Abbott Laboratórios do Brasil Ltda.

Figure 1.Experiment outline.

2083_IPC_AAP_553033 3/7/03 12:05 PM Page 339

Treatment of Peri-Implantitis by Lethal Photosensitization Volume 74 • Number 3

Each animal received anti-inflammatory medication(2 mg betamethasone¶¶¶ twice a day) and appropri-ate analgesia (acetaminophen) for 3 days followingsurgery to reduce postoperative swelling and pain.Sutures were removed 2 weeks after surgery. Oral pro-phylaxis was performed with 0.12% chlorhexidine dailyfor 5 months. Sites were observed daily for gingivalhealth, maintenance of suture line closure, materialexposure, or infection.

A fluorochrome### (25 mg/kg body weight) wasinjected 19 weeks after lethal photosensitization. Fivemonths after surgery, the animals were sacrificed byinduction of deep anesthesia followed by intravenoussodium pentobarbital euthanasia.

Histological ProceduresThe mandibles were removed and block biopsies ofeach implant site were dissected. The biopsies were

Figure 2.A. Clinical view of peri-implant defects beforesurgical debridement. B. Peri-implant defectsadjacent to HA surface after surgical debridementwith plastic curets. C. ePTFE membranes placedover the dental implants fixed with cover screwsand CPTi tacks.

*** Sigma Ltd., Poole, UK.††† IR 500-Laser Beam, São Paulo, Brazil.‡‡‡ G-TAM, W.L. Gore & Associates, Inc., Flagstaff, AZ.§§§ Sitema INP, Implantes Nacionais e de Proteses Comercio Ltda, SP,

Brazil.� � � Gore-Tex sutures, W.L. Gore & Associates, Inc.¶¶¶ Celestone, Schering-Plough S/A, Rio de Janeiro, RJ, Brazil.### Oxytetracycline, Pfizer do Brasil, São Paulo, SP, Brazil.

340

The implant surface was then rinsed with physio-logical saline solution. TBO*** (100 µg/ml)6,9,17 wasthen injected into the peri-implant defect as far as thebony border with a thin needle. TBO was left in placefor 1 minute and then carefully drawn off. The stainedarea, including the implant surface and peri-implantbone defect, was subsequently irradiated with a GaAlAsdiode laser††† with a measured power output of 50 mW.This laser emits radiation in collimated beams (2 mm2)with a wavelength of 685 nm for 80 seconds and atotal energy of 4J (energy density, 200 J/cm2). Thelaser was focalized in contact with the mesial, distal,buccal, and lingual surfaces by a scanning method for20 seconds on each face, for a total of 80 seconds. AnePTFE membrane‡‡‡ was placed to cover the implants.

The membranes extended circumferentially 3 to5 mm over the adjacent alveolar bone to excludeingrowths of soft connective tissue and were stabilizedby CPTi tacks§§§ on the buccal and lingual aspectsand cover screws (Fig. 2C). After clot positioning andmembrane placement, periosteal releasing incisionswere made buccally and lingually to allow tension-freeflap apposition and closure. Primary wound closurewas achieved with horizontal mattress sutures alter-nated with interrupted ePTFE sutures.� � �

2083_IPC_AAP_553033 3/7/03 12:05 PM 40


341

fixed in 4% neutral formalin for 48 hours and then pre-pared for ground sectioning according to previouslydescribed methods.20 The specimens were cut into amesio-distal plane using a cutting-grinding unit.****From each implant site, one central section was pre-pared and reduced to a final thickness of 50 to 70 µmby microgrinding and polishing.†††† Before staining,each section was evaluated regarding the location ofthe fluorochrome marker. The analysis was carried outwith a microscope‡‡‡‡ equipped with an image sys-tem.§§§§ In the unstained sections, fluorescence lightand a filter cube compatible to the fluorochrome wereused to check the osseointegration in the one-thirdapical area of the implant not affected by peri-implantinfection, and to assess the bone remodeling 24 monthsafter insertion.

The sections were then stained with toluidine blueto assess the histometric parameters (Fig. 3): 1 = dis-tance from the bottom of original defect, identified bythe difference in coloration after staining (a) to themost coronal point of the newly formed bone with inti-mate contact to the implant surface (b = reosseointe-gration); 2 = area of (a) to the most apical border ofthe newly formed bone; c = to implant shoulder; d =bone fill; 3 = percentage of osseointegration (mineral-ized bone contact with the implant surface); and 4 =bone area within the limits of the implant threads atthe portion of the implant, apical of the peri-implantdefect where peri-implantitis did not occur. The datawere obtained in pixels2 and transformed into per-centages to avoid the influence of the differentmacrostructure among the dental implants.

RESULTSClinical ObservationsNineteen implants successfully integrated and survivedthe subsequent treatment periods including mechani-cal debridement, lethal photosensitization, and GBR.Clinically, the 3 HA dental implant surfaces appearedto be resorbed (Fig. 4A). Heavy calculus deposits werealso observed in some dental implants (Figs. 2A and

Figure 3.Schematic drawing illustrating the landmarks used for histometricmeasurements.

**** Exact Cutting System, Apparatebau, Gmbh, Hamburg, Germany.†††† Exact System, Apparatebau, Gmbh.‡‡‡‡ Leitz DM-RBE microscopy, Leica, Bensheim, Germany.§§§§ Qwin, Leica.

Figure 4.A. Clinical view of partially resorbed HA-coated implant after peri-implantitis infection. B. Calculus (arrow) 14 months after experimentalperi-implantitis on AE surface.

2083_IPC_AAP_553033 3/7/03 12:05 PM Page 341


342

4B). None of the membranes placed to treat the peri-implantitis defects had to be removed.

Histological Examinations and MeasurementsThe peri-implant soft and hard tissues generallyappeared healthy. The alveolar bone was apical to theconnective tissue, and the implants were embedded toa noticeable variable height. The old bone was mostlylamellar and compact, and numerous osteocytes wereevident in their lacunae (Fig. 5A). The newly formedbone exhibited different stages of maturation and

remodeling. When observed under fluorescent light, thepresence of bone remodeling adjacent to dental implantscrews was present at 19 months (Fig. 5B).

The defects created by the 2 months of ligature-induced plaque accumulation and 12 months ofsupragingival plaque control amounted histometricallyto 5.86 ± 2.24 mm (TPS); 5.52 ± 0.73 mm (HA); 4.68± 1.39 mm (AE); and 3.26 ± 1.58 mm (CPTi).

The highest proportion of mineralized bone contactwith the dental implant surface was seen with HA(75.69% ± 12.94), followed by TPS (58.95% ± 2.43),AE (62.40% ± 9.62), and CPTi (52.73% ± 4.47). Themean and standard deviation of the bone area within thelimits of the implant threads showed the highest per-centage in HA (79.29 ± 5.35), followed by TPS (75.87± 16.32), AE (51.61 ± 12.65), and CPTi (48.40 ± 11.39).Figures 6A and 6B characterize the percentage of bonefill, which amounted to 48.28 ± 15.00; 39.54 ± 12.34;26.88 ± 22.16; and 26.70 ± 16.50 for HA, TPS, AE, andCPTi, respectively. In some specimens, the lateral aspectof the coronal part of the dental implant, i.e., the pre-viously contaminated portion, was covered by a denseconnective tissue capsule that separated the newlyformed bone from the dental implant surface (Fig. 7).

The percentage of reosseointegration (Figs. 8A and8B) was 25.25 ± 11.96 for the TPS surface, 24.91 ±17.78 for the CPTi surface, 17.30 ± 15.41 for the AEsurface, and 15.83 ± 9.64 for the HA surface. However,in one AE specimen, there was no observation of newbone in contact with the previously contaminatedimplant surface (Fig. 9). Data for acid surface, as wellas for the other surfaces, demonstrate that all implantsremained in place. Therefore, we considered all 19sites, even though one specimen did not demonstratereosseointegration.

DISCUSSIONThe difficulties in obtaining reosseointegration aftertreatment of peri-implantitis have been documented inseveral animal studies.2,3,21-23 Most of these studiesutilized systemic antibiotics associated with air-powderabrasive8,24,25 or mechanical debridement.4,23,26 To ourknowledge, this pilot study was the first to histometri-cally evaluate the treatment of induced peri-implantitisusing lethal photosensitization associated with guidedbone regeneration.

Recently, several studies have demonstrated the bac-tericidal effect of high-power lasers on contaminateddental implant surfaces.27-29 This energy is specificallyabsorbed by water molecules, which causes the water-rich tissue to be preferentially vaporized. In bacterialcytoplasm, this effect causes cell lyses and variabledegrees of damage to the dental implant surface.

In addition, other studies6,9,17 have shown the effec-tiveness of lethal photosensitization in decreasing theviable count of periodontal pathogens in peri-implan-

Figure 5.A. Ground section of AE surface where peri-implantitis did not occur(toluidine blue, original magnification ×80). B. Mesio-distal groundsection of a CPTi surface.The fluorochrome shows the bone remodelingat 19 months (fluorescence; original magnification ×100).

2083_IPC_AAP_553033 3/7/03 12:05 PM Page 342


343

titis lesions without damage to thedental implant surface.

The histometric analysis depictsnew bone formation in variabledegrees in all dental implant sur-faces tested. Although the per-centage of bone fill observed instudies such as Wetzel et al.23 andPersson et al.26 was higher, ourresults ranged from 48.28% forHA surface to 26.70% for the CPTisurface, in agreement with Pers-son et al.,3 although their data uti-lized only CPTi surfaces.

Reosseointegration was achievedwith all dental implant surfacesprincipally at the base of theangular bony defect, in agreementwith Persson et al.,7 Jovanovic etal.,24 and Singh et al.30 The high-est percentage observed in ourinvestigation was 25.25 ± 11.96(TPS) and the lowest 15.83 ± 9.64(HA), in the same range asHanisch et al.22 and Wetzel et al.23

Despite controversy on the amountof reosseointegration,3,4,7,8,24-26

these different results can beattributed to experimental designs

and variables such as ligature-induced peri-implanti-tis period, microstructure utilized, cleansing methodsof contaminated implant surface and their efficiency,bony defect shape, and combination of graft materi-als and GBR. The different dental implant surfaces,their chemical compositions (CPTi, HA, TPS, AE), andtheir different surface-free energies did seem to be rel-evant for the amount of histometrical variables.

On the other hand, Persson et al.26 found 83.7 ± 8.6%reosseointegration in sandblasted, large-grit, acid-etchedsurface (SLA) and 21.8 ± 16.7% for turned surface. Theauthors speculated that the SLA surface could providea better condition for coagulum stability, facilitating thebone regeneration process. In addition, it has also beensuggested that single monolayers from the environmentor bulk material can invalidate or make reosseointegra-tion more difficult.31,32 However, these results are nottotally understood. The other important observation real-ized in this study was the dissolution of HA coating afterperi-implant infection. Factors such as thickness of coat-ing and crystallinity of the coating may be altered dueto periodontal pathogen exposure.33 Consequently, thisfactor could complicate peri-implantitis treatment. It canbe speculated that the poorest results would be achievedusing dental implants with HA coatings. However, theseresults should be analyzed with caution due to the smallsample size used in our study.

Figure 6.A. Mesio-distal ground section of an HA surface showing the borderline between the “old” originalbone (OB) and the newly formed bone (NB) (toluidine blue staining; original magnification ×40). B.Mesio-distal ground section of a TPS surface showing the borderline (arrows) between the “old”original bone (OB) and the newly formed bone (NB) in the apical portion of the peri-implant defect(toluidine blue staining; original magnification ×40).

Figure 7.Histologic section showing dense connective tissue at the implant/newbone interface (arrows) (polarized light; original magnification ×40).

2083_IPC_AAP_553033 3/7/03 12:05 PM Page 343


344

A dense connective tissue cap-sule that separated the newlyformed bone from the dentalimplant surface was observed insome specimens, which agreeswith Persson et al.3,4 and Wetzelet al.23 In these studies, the treat-ment utilized systemic antibioticsand chemical means: delmopinolor chlorhexidine. These sub-stances formed a dense, stablefilm 7 to 10 nm thick on the oxidelayer of the dental implant sur-face.32 According to Persson etal.,7 this film may prevent bonefill and reosseointegration. In ourstudy, the utilization of lethal pho-tosensitization presented similarresults. However, we could notconclude that either TBO aloneor TBO plus diode laser wouldform the same film.

In addition, the use of lethalphotosensitization to kill periodon-tal pathogens offers some advan-tages over the use of conventionalantimicrobials. It avoids develop-ment of resistance among targetorganisms to the photochemicallygenerated free radicals thought to

be responsible for bacterial killing and, unlike anti-septics and antibiotics, there is no need to maintainhigh concentrations of the TBO in the peri-implantdefects for long periods.

In conclusion, data from the present pilot study sug-gest that the treatment of chronic peri-implantitis bymeans of lethal photosensitization may obtain significantbone fill associated with reosseointegration. However,these results should be considered with caution andfurther investigations must be conducted.

ACKNOWLEDGMENTSThis research project was supported by FAPESP (Fun-daÇão de Amparo a Pesquisa do Estado de São Paulo)grants 00/02433-1 and 1999/03026-1. The authorsappreciate the assistance of Dr. Jose T.T. Siqueira (INP-Implantes Nacionais e Próteses, São Paulo, Brazil) and3i Brazil for supplying the titanium tacks and dentalimplants, respectively. The authors wish to thank Drs.Kaline Olimpia de Souza, Susana d’Avila, Rogerio Marg-onar, and Celso Sakakura for their invaluable assis-tance in the surgical phase and maintenance care.

REFERENCES1. Lang NP, Bragger U, Walther D, Beamer B, Kornman

KS. Ligature-induced peri-implant infection in cynomol-gus monkeys. I. Clinical and radiographic findings. Clin

Figure 8.A. Mesio-distal ground section of a TPS surface showing the borderline between the “old” originalbone (OB) and the newly formed bone (NB) in direct contact with the dental implant surface, whichwas previously contaminated (reosseointegration) (toluidine blue staining; original magnification×100). B. Detail depicting reosseointegration on CPTi surface. Note that direct contact wasestablished between the newly formed bone (NB) and the previously contaminated portion of thedental implant surface (arrows) (toluidine blue staining; original magnification ×100).

Figure 9.Ground section of acid surface showing the absence of direct contactbetween the newly formed bone (NB) and the dental implant surface(toluidine blue staining; original magnification ×100).

2083_IPC_AAP_553033 3/7/03 12:06 PM Page 344


345

Oral Implants Res 1993;4:2-11.2. Ericsson I, Persson LG, Berglundh T, Edlund T, Lindhe

J. The effect of antimicrobial therapy on peri-implanti-tis lesions. An experimental study in the dog. Clin OralImplants Res 1996;7:320-328.

3. Persson LG, Ericsson I, Berglundh T, Lindhe J. Guidedbone regeneration in the treatment of periimplantitis.Clin Oral Implants Res 1996;7:366-372.

4. Persson LG, Araujo MG, Berglundh T, Grondahl K, LindheJ. Resolution of periimplantitis following treatment. Anexperimental study in the dog. Clin Oral Implants Res1999;10:195-203.

5. Hammerle CHF, Fourmousis I, Winkler JR, Weigel C,Bragger U, Lang NP. Succesful bone fill in late peri-implant defects using guided tissue regeneration. A shortcommunication. J Periodontol 1995;66:303-308.

6. Hass R, Baron M, Dortbudak O, Watzek G. Lethal pho-tosensitization, autogenous bone, and e-PTFE membranefor the treatment of peri-implantitis: Preliminary results.Int J Oral Maxillofac Implants 2000;15:374-382.

7. Persson LG, Ericsson I, Berglundh T, Lindhe J. Osseoin-tegration following treatment of peri-implantitis andreplacement of implant components. An experimentalstudy in the dog. J Clin Periodontol 2001;28:258-263.

8. Hurzeler MB, Quinones CR, Schupbach P, Morrison EC,Caffesse RG. Treatment of peri-implantitis using guidedbone regeneration and bone grafts, alone or in combi-nation, in beagle dogs. Part 2: Histologic findings. Int JOral Maxillofac Implants 1997;12:168-175.

9. Dörtbudak O, Haas R, Bernhard T, Mailath-Pokorny G.Lethal photosensitization for decontamination of implantsurfaces in the treatment of peri-implantitis. Clin OralImplants Res 2001;12:104-108.

10. Wainwright M. Photodynamic antimicrobial chemother-apy (PACT). J Antimicrob Chemother 1998;42:13-28.

11. Dobson J, Wilson M. Sensitization of oral bacteria inbiofilms to killing by light from a low power laser. ArchOral Biol 1992;37:883-887.

12. Sarkar S, Wilson M. Lethal photosensitization of bacte-ria in subgingival plaque samples from patients withchronic periodontitis. J Periodont Res 1993;28:204-210.

13. Henry CA, Judy M, Dyer B, Wagner M, Matthews J. Sen-sitivity of Porphyromonas and Prevotella species in liq-uid media to argon laser. Photochem Photobiol 1995;61:410-413.

14. Bhatti M, MacRobert A, Meghji S, Henderson B, WilsonM. Effect of dosimetric and physiological factors on thelethal photosensitization of Porphyromonas gingivalis invitro. Photochem Photobiol 1997;65:1026-1031.

15. Bhatti M, MacRobert A, Meghji S, Henderson B, WilsonM. A study of the uptake of toluidine blue O by Por-phyromonas gingivalis and the mechanism of lethal pho-tosensitization. Photochem Photobiol 1998;68:370-376.

16. Bhatti M, MacRobert A, Henderson B, Shepherd P, Crid-land J, Wilson M. Antibody-targeted lethal photosensi-tization of Porphyromonas gingivalis. Antimicrob AgentsChemother 2000;44:2615-2618.

17. Haas R, Dörtbudak O, Mensdorff-Pouilly N, Mailath G.Elimination of bacteria on different implant surfacesthrough photosensitization and soft laser. An in vitrostudy. Clin Oral Implants Res 1997;8:249-254.

18. Legrand-Poels S, Hoebeke M, Vaira D, Rentier B, PietteJ. HIV-1 promoter activation following an oxidative stressmediated by singlet oxygen. J Photochem Photobiol B1993;17:229-237.

19. Minnock A, Vernon DI, Schofield J, Griffiths J, ParishJH, Brown ST. Photoinactivation of bacteria. Use of a

cationic water-soluble zinc phthalocyanine to photoin-activate both Gram-negative and Gram-positive bacte-ria. J Photochem Photobiol B 1996;32:159-164.

20. Donath K, Breuner GA. A method for undecalcified bonesand teeth with attached soft tissues. The Sage-Schlifftechnique. J Oral Pathol 1982;11:318-325.

21. Grunder U, Hurzeler MB, Schupbach P, Strub JR. Treat-ment of ligature-induced peri-implantitis using guidedtissue regeneration: A clinical and histological study inthe beagle dog. Int J Oral Maxillofac Implants 1993;8:282-293.

22. Hanisch O, Tatakis DN, Boskovic M, Rohrer MD, WikesjöUME. Bone formation and re-osseointegration in peri-implantitis defects following surgical implantation ofrhBMP-2. Int J Oral Maxillofac Implants 1997;12:604-610.

23. Wetzel AC, Vlassis J, Hammerle CHF, Lang NP. Attemptsto obtain re-osseontegration following experimentalperi-implantitis in dogs. Clin Oral Implants Res 1999;10:111-119.

24. Jovanovic SA, Kenney EB, Carranza FA, Donath K. Theregenerative potential of plaque induced peri-implantbone defects treated by submerged membrane tech-nique: An experimental study. Int J Oral MaxillofacImplants 1993;8:13-18.

25. Nociti FH Jr., Machado MAN, Stefani CM, Sallum EA.Absorbable versus nonaborbable membranes and bonegrafts in the treatment of ligature-induced peri-implan-titis defects in dogs: A histometric investigation. Int JOral Maxillofac Implants 2001;16:646-652.

26. Persson LG, Berglundh T, Lindhe J, Sennerby L. Re-osseointegration after peri-implantitis at different implantsurfaces. An experimental study in the dog. Clin OralImplants Res 2001;12:595-603.

27. Kato T, Kusakari H, Hoshino E. Bacterial efficacy of car-bon dioxide laser against bacteria-contaminated tita-nium implant and subsequent cellular adhesion to irra-diated area. Lasers Surg Med 1998;23:299-309.

28. Mouhyi J, Sennerby L, Nammour S, Guillaume P, VanReck J. Temperature increase during surface deconta-mination of titanium implants using CO2 laser. Clin OralImplants Res 1999;10:54-61.

29. Mouhyi J, Sennerby L, Van Reck J. The soft tissueresponse to contamination and cleaned titanium sur-faces using CO2 laser, citric acid and hydrogen perox-ide. An experimental study in the rat abdominal wall.Clin Oral Implants Res 2000;11:93-98.

30. Singh G, O’Neal RB, Brennam WA, Strong SL, HornerJA, Van Dyke TE. Surgical treatment of induced peri-implantitis in the micro pig: Clinical and histologicalanalysis. J Periodontol 1993;64:984-989.

31. Esposito M, Lausmaa J, Hirsch JM, Thomsen P. Sur-face analysis of failed oral titanium implants. J BiomedMater Res 1999;48:559-568.

32. Krozer A, Hall J, Ericsson I. Chemical treatment ofmachined titanium surfaces. An in vitro study. Clin OralImplants Res 1999;10:204-211.

33. Mukherjee DP, Dorairaj NR, Mills DK, Graham D, KrauserJT. Fatigue properties of hydroxyapatite-coated dentalimplants after exposure to a periodontal pathogen.J Biomed Mater Res 2000;53:467-474.

Correspondence: Dr. Elcio Marcantonio Jr., Departamento dePeriodontia, Faculdade de Odontologia de Araraquara –UNESP, R. Humaitá, 1680, 14801–903 Araraquara – SP,Brazil. Fax: 55 16 201 6314; e-mail: [email protected].

Accepted for publication July 22, 2002.

2083_IPC_AAP_553033 3/7/03 12:06 PM Page 345

treatment of ligature-induced peri-implantitis by lethal...

Documents