Treatment of experimental periodontal disease by photodynamic therapy in immunosuppressed rats

Treatment of experimentalperiodontal disease byphotodynamic therapy inimmunosuppressed rats

Fernandes LA, de Almeida JM, Theodoro LH, Bosco AF, Nagata MJH, Martins TM,Okamoto T, Garcia VG. Treatment of experimental periodontal disease byphotodynamic therapy in immunosuppressed rats. J Clin Periodontol 2009; 36:219–228. doi: 10.1111/j.1600-051X.2008.01355.x.

AbstractBackground and Objective: The aim of this study was to compare photodynamictherapy (PDT) as an adjunctive treatment of induced periodontitis with scaling androot planing (SRP) in dexamethasone-inhibited rats.

Material and Methods: The animals were divided into two groups: ND (n 5 90),saline solution treatment; D (n 5 90), dexamethasone treatment. In the ND and DGroups, periodontal disease was ligature-induced at the first mandibular molar. After7 days, the ligature was removed and all animals received SRP and were dividedaccording to the following treatments: SRP, saline solution; Toluidine Blue-O (TBO),phenothiazinium dye; and PDT, TBO and laser irradiation. Ten animals in eachtreatment were killed at 7, 15 and 30 days. The radiographic and histometric valueswere statistically analysed.

Results: In the ND and D Groups, radiographic analysis showed less bone loss inanimals treated by PDT in all the experimental periods than SRP and TBO at 15 days(po0.05). After a histometric analysis was carried out in the ND and D groups, theanimals treated by PDT showed less bone loss in all periods than SRP and TBO after15 days (po0.05).

Conclusions: The PDT was an effective adjunctive treatment of induced periodontitiscompared with SRP in dexamethasone-inhibited rats.

Key words: animal model; non-surgicalperiodontal therapy; periodontal disease;periodontal therapy; systemic host effect

Accepted for publication 26 October 2008

Periodontal disease is the result of thecollapse of teeth-supporting structuresby the local action of periodontopatho-genic microorganisms. These microor-

ganisms release substances that strictlyinjure periodontal tissues, besides indu-cing tissue destruction by inflammatoryand immunologic responses of the host(Kamma & Slots 2003).

The placement of ligatures aroundteeth to initiate periodontal tissue losshas been carried out in various animalexperimental models. The use of liga-ture in rats as an experimental modelwas realized in the present studybecause many of the same series ofevents occur in this animal as in thenon-human primate (Graves et al. 2008).This experimental model is character-ized by accumulation of plaque, flatten-

ing and displacement of the gingivalcrest, increased proliferation of theepithelium into underlying connectivetissue and infiltration of mononuclearinflammatory cells. Like human perio-dontitis, alveolar bone loss in the liga-ture model is dependent on bacteria, andthe destructive phase of ligature-inducedexperimental periodontitis is associatedwith a host response. Further, the ratligature model is sensitive to systemiceffects such as drug therapy (Graveset al. 2008).

Systemic factors such as diabetes,tobacco and stress have been found tobe associated with severe and/or rapidly

Leandro Araujo Fernandes1, JulianoMilanezi de Almeida1, Leticia HelenaTheodoro2, Alvaro Francisco Bosco1,Maria Jose Hitomi Nagata1, ThiagoMarchi Martins1, Tetuo Okamoto1

and Valdir Gouveia Garcia1

1GEPLO – Group of Study and Research on

Laser in Dentistry, Division of Periodontics,

Department of Surgery and Integrated Clinic,

Sao Paulo State University (UNESP),

Aracatuba, SP, Brazil; 2Department of

Periodontics, University Center of

Educational Foundation of Barretos

(UNIFEB), Barretos Dental School, Barretos,

SP, Brazil

Conflict of interest and source offunding statement

The authors declare that they have noconflict of interests.This study has been self-supported by theDepartment of Periodontology, AracatubaDental School, State University of SaoPaulo (UNESP) Aracatuba, Sao Paulo,Brazil, and by CAPES – Coordination forthe Improvement of Higher Education Per-sonnel (Brasilia, DF, Brazil).

J Clin Periodontol 2009; 36: 219–228 doi: 10.1111/j.1600-051X.2008.01355.x

219r 2009 John Wiley & Sons A/S

progressive periodontitis (Breivik et al.2006). Furthermore, some medicationshave an impact on the periodontiumand its response to bacterial plaque(Seymour 2006).

In the last decades, organ transplanthas become an accepted treatment for arange of acquired and congenital disor-ders. Corticoids are commonly used totreat many different diseases because oftheir anti-inflammatory effect and immu-nosuppressant properties. Glucocorti-coids link to receptors inside the celland cause redistribution of the lympho-cytes. They also reduce T-cell prolifera-tions, with a decrease in interleukin-2,and also down-regulate interleukin-1 andinterleukin-6, thereby curtailing inflam-mation (Vasanthan & Dallal 2007).

Prolonged therapy with corticoidsmay favour osteoporosis, which is nowregarded as a risk factor for periodontaldisease (Seymour 2006). The systemicuse of drugs such as non-steroidal anti-inflammatory substances and their pos-sible effects on periodontal disease havebeen studied (Lipari et al. 1974, Safkan& Knuuttila 1984, Cavagni et al. 2005,Breivik et al. 2006). Experimental stu-dies have demonstrated that the use ofcorticoid can induce gingival ulceration,upward to downward migration of theepithelium, attachment loss and transep-tal fibre disruption (Lipari et al. 1974,Cavagni et al. 2005). In addition, thesystemic use of high doses of glucocor-ticoids leads to fibroblast activity inhibi-tion, collagen and connective tissue loss,with decreased re-epithelization andangiogenesis (Pessoa et al. 2004), areduction of the number and activity ofthe osteoblasts and increased osteoclastfunction (Sattler et al. 2004). However,clinical studies are somewhat equivocalwith respect to the effect of systemicglucocorticoids on periodontal tissues(Safkan & Knuuttila 1984, Oettinger-Barak et al. 2007).

The periodontal disease treatment isbased on pathogenic microbiota reduc-tion by scaling and root planing (SRP)(Kaldahl et al. 1993). However, themechanical therapy used may fail toeliminate pathogenic bacteria that areplaced into the soft tissue, and also inareas inaccessible to the periodontalinstruments, such as furcation area androot depression (Matia et al. 1986,Adriaens et al. 1988).

Systemic disease and adverse drugreactions deal with strategic challengesto the elaboration of a conventionalperiodontal treatment plan, leading to

the use of complementary therapiesin order to compensate the intrinsicalterations related to a periodontal repairprocess. Because of these limitations,adjunctive methods that promote reduc-tion or elimination of periodontal patho-gens have attracted the attention ofmany researchers (Faveri et al. 2006,Derdilopoulou et al. 2007, Kaner et al.2007, Needleman et al. 2007, Lee et al.2008). On the other hand, the literaturealso evidences uncountable researchesthat demonstrate the selection and resis-tance of bacteria promoted by the over-use of antimicrobial drugs in theperiodontal therapy (VanWinkelhoffet al. 1996).

Recently, some in vitro (Sarkar &Wilson 1993, Chan Lai 2003, Zaninet al. 2005) and in vivo studies (Komeriket al. 2003, Sigusch et al. 2005, Almeidaet al. 2007, 2008, Andersen et al. 2007,Qin et al. 2007) have showed satisfac-tory results with the utilization of photo-dynamic therapy (PDT). This therapyconsists of the association of a photo-sensitizer with an intense light sourcewith the objective to promote cellulardeath. The photodynamic activity ofphotosensitizers is based on photo-oxidative reactions that induce bio-chemical and morphologic alterationsin target cells. When the photosensitizerdrug molecule absorbs light from aresonant energy, it is transformed intoa single exciting state. Depending on itsmolecular structure and environment,the molecule may then lose its energyby an electronic or a physical process,thus returning to the ground state, or itmay undergo a transition to the tripletexciting state (electron spins unpaired).At this stage, the molecule may onceagain undergo electronic decay back tothe ground state, it may develop a redoxreaction with its environment or itsexcitatory energy may be transferred tomolecular oxygen (also a moleculartriplet state), leading to the formationof a labile singlet oxygen (type-II reac-tion). This oxygen reactive species isresponsible for irreversible damage onthe bacterial cytoplasm membrane,including protein modification, respira-tory chain and nucleic acid alterations(Wainwright 1998).

The major advantages of PDT areas follows: it is a specific therapy fortarget cells, it exerts no collateral effect,initiating its activity only when lightexposed, and it supports no resistantbacteria species selection (Maisch2007), which is quite common with

the indiscriminate use of antibiotics(VanWinkelhoff et al. 1996).

The introduction of PDT as anadjunctive periodontal treatment underimmunosuppression conditions has notbeen reported in the literature. Consider-ing that prolonged use of corticoidsis associated with a reduction of thenumber and activity of the osteoblasts(Sattler et al. 2004) and increased oste-clastic function (Sattler et al. 2004), thePDT may be an alternative adjunctivemethod for non-surgical periodontaltreatment under immunosuppression con-ditions.

In this context, the aim of the presentstudy was to evaluate, radiographic, histo-logically and histometrically, the efficacyof PDT plus conventional mechanicaltherapy compared with SRP alone ofalveolar bone loss of experimental perio-dontitis induced both in normal andin systemically dexamethasone-inhibitedrats.

Materials and Methods

Animals

This study was conducted on 180 adultmale Wistar rats (120–140 g). The ani-mals were kept in plastic cages withaccess to food and water ad libitum.Before the surgical procedures, all ani-mals were allowed to acclimatize to thelaboratory environment for a period of5 days. All protocols described belowwere approved by the InstitutionalReview Board of Aracatuba DentalSchool, Sao Paulo State University,Aracatuba, SP, Brazil (no. 22/06).

Experimental design

Protocol of drug administration

The animals were numbered and dividedrandomly into two groups of 90 ratseach one: the D Group (n 5 90) receivedinjections of 2 mg/kg (Pessoa et al.2004) of body weight of dexamethasone(DECADRONs 2 mg, Prodome) (AchePharmaceutical Laboratories SA, Cam-pinas, SP, Brazil); the ND Group(n 5 90), non-dexamethasone – receivedinjections of 2 mg/kg (Pessoa et al.2004) of body weight of saline solution.The subcutaneous injections wereinitiated 24 h before the experimentalinduction of periodontal disease andmaintained every 3 days (Cavagniet al. 2005), during all the periods ofkilling (Fig. 1).

220 Fernandes et al.

r 2009 John Wiley & Sons A/S

The injection was administered on thebacks of the animals, next to the cepha-lic region, and the injections werealways been scheduled during the morn-ing period. The animals were weighedweekly with regard to dose maintenancethroughout the experimental period.

Protocol of experimental periodontaldisease

General anaesthesia was administeredby a combination of ketamine (0.4 ml/kg) with xylazine (0.2 ml/kg) via anintra-muscular injection. One mandibu-lar first left molar of each animal in theND and D Groups was selected toreceive the cotton ligature in the sub-marginal position in order to induceexperimental periodontites (Nociti et al.2000). The contralateral, mandibularfirst molar in the animals of each group(right side) received neither the ligaturenor any treatment. After 7 days ofperiodontal disease experimental induc-tion, the ligature of the mandibular firstleft molar was removed in all animals ofthe ND and D Groups. The left molarswere subjected to SRP with manual#13–14 mine five curettes (Hu-FriedyCo. Inc., Chicago, IL, USA) through 10distal–mesial traction movements in thebuccal and lingual aspects. The furca-tion and interproximal areas were scaledwith the same curettes through cervico-occlusal traction movements. SRP wasperformed by the same experiencedoperator. The 90 animals of each group(ND and D) were randomly allocated,using a computer-generated table, to thetreatments SRP, Toluidine Blue-O(TBO) and PDT. For better standardiza-tion, animal 1 was the first choice,followed by 2 and 3, respectively.Thus, the animals of each group (NDand D) were randomly assigned to oneof the three treatments (30 animals/treatment): SRP, the mandibular leftmolars were subjected to SRP and irri-gation with 1 ml of saline solution;Phenotiazinium dye (TBO; Sigma Che-mical Co., St. Louis, MO, USA), themandibular left molars were subjectedto SRP and irrigation with 1 ml of TBO

(100mg/ml) solution; and PDT, the man-dibular left molars were subjected toSRP and irrigation with 1 ml of TBO(100mg/ml) solution, followed by appli-cation of a low-intensity laser (LLLT)after 1 min. (Fig. 1).

PDT treatment

The low-intensity laser used in thisstudy was Gallium–Aluminum–Arsenide (GaAlAs) (GaAlAs; LaserBio Wave LLLT; Kondortech Equip-ment, Sao Carlos, SP, Brazil) with awavelength of 660 nm and a spot size of0.07 cm2. After 1 min. of TBO applica-tion, the LLLT was used in three equi-distant points at each buccal and lingualaspect of the first mandibular molar incontact with the tissue. The treatmentlaser was released with a power of0.03 W at 133 s/point, a power densityof 0.428 W/cm2 and energy of 4 J/point(57.14 J/cm2/point). The area received atotal energy of 24 J. Saline solution andTBO were deposited into the perio-dontal pocket slowly using a syringe(1 ml) and an insulin needle (13 mm �0.45 mm) (Becton Dickinson Ind. Ltd.,Curitiba, PR, Brazil) without bevel.

Experimental periods

Ten animals of each group and treat-ment were killed at 7, 15 and 30 daysafter the periodontal disease treatmentby administration of a lethal dose ofthiopental (150 mg/kg) (Cristalia Ltd.,Itapira, SP, Brazil). The jaws wereremoved and fixed in 10% neutral for-malin for 48 h.

Laboratory procedures

The specimens were demineralized ina solution consisting of equal parts of50% formic acid and 20% sodium citratefor 15 days. Paraffin serial sections(6mm) were obtained in the mesiodistaldirection and dyed with haematoxylinand eosin (H&E) or Masson’s Trichro-mic (MT).

Radiographic analysis

Rat left mandibles were removed to deter-mine the degree of bone loss. Standar-dized radiographs were obtained usingdigital radiographic images provided bythe computerized imaging system Digora(Soredex, Orion Corporation, Helsinki,Finland), which uses a sensor instead ofan X-ray film. Electronic sensors wereexposed at 70 kV and 8 mA with anexposure time of 0.4 s. The source-to-film distance was 50 cm. The distancebetween the cementum–enamel junctionand the height of alveolar bone wasdetermined for the mesial root surface ofthe mandibular left first molars (Holzhau-sen et al. 2002). Bone loss was measuredin millimetres for each radiograph in themask mode three times by the sameexaminer.

Histological and histometric analysis

Sections dyed by H&E were analysedby light microscopy to establish thebone loss and characteristics of perio-dontal ligament in the furcation regionof first molars. Collagen fibres wereanalysed in sections dyed by MT.

The area of bone loss in the furca-tion region was histometrically deter-mined using an image analysis system(Image Tool, University of TexasHealth Science Center at San Antonio,San Antonio, TX, USA). After exclud-ing the first and the last sections wherethe furcation region was evident, fiveequidistant sections of each specimenblock were selected and captured by adigital camera connected to a lightmicroscope. The mean values wereaveraged and compared statistically.One mask-trained examiner selectedthe sections for histometric and histolo-gical analyses. Another mask-calibratedexaminer conducted the histometricanalysis. The bone loss at each speci-men section was measured three timesby the same examiner, on different days,in order to reduce the variation in thedata (Almeida et al. 2008).

Intra-examiner reproducibility

Before the radiographic and histometricanalyses were performed, the exami-ner was trained by double measure-ments of 20 specimens, with a 1-weekinterval. Paired t-test statistics wererun and no differences were obser-ved in the mean values for com-parison (p-value 5 0.51). Additionally,

Fig. 1. Experimental design.

PDT reduces bone loss in immunosuppressed conditions 221


Pearson’s correlation coefficient wasobtained between the two measurementsand revealed a very high correlation(0.99, p 5 0.000).

Statistical analysis

The hypothesis that there were no differ-ences in bone loss rate in the furcationregion between treatment groups wastested by Bioestat 3.0 software (Bioestat,Windows 1995; Sonopress BrazilianIndustry, Manaus, AM, Brazil).

After the normality of radiographicand histometric data was analysed bythe Shapiro–Wilk test, intra- and inter-group analyses were carried out using atwo-way analysis of variance (ANOVA;po0.05). When ANOVA detected a sta-tistically significant difference, multiplecomparisons were performed usingTukey’s test (po0.05).

Results

Clinical analysis

All the ND Group animals, regardless ofthe treatment, showed no clinical differ-ences in general health, and weight gainwithin the predicted range for healthyrats (Table 1).

The D Group showed progressiveweight loss, at a significant level whencompared with the ND animals (Table 1),which show trends of immunossuppres-sion and systemic alterations.

Radiographic analysis

In both groups (ND and D), radiographicexamination showed that there was sig-nificantly less bone loss in the animalstreated by PDT in all experimental periodsthan SRP and TBO after 15 days (Fig. 2).Inter-group radiographic analysis (NDand D Groups) demonstrated that, in theND Group, treated with SRP, there wasgreater bone loss compared with the DGroup, treated with PDT at 7 and 30 days(Fig. 2).

Histological analysis

SRP treatment

At 7, 15 and 30 days, most specimens inthe ND Group that received the SRPtreatment showed connective tissue witha high number of neutrophils in degen-eration, bone tissue with thin bone tra-beculae and resorption areas. At 7, 15and 30 days, most specimens in the D

Group that received SRP treatmentshowed disorganized connective tissuewith a small number of fibroblasts.There were bone resorption areas withthin bone trabeculae and an intenseinflammatory infiltrate (Fig. 3). Thecementum surface in most specimensshowed resorption areas.

TBO treatment

At 7, 15 and 30 days, most specimens inthe ND and D (Fig. 4) Groups, whichreceived the TBO treatment, showedorganized bone and connective tissues,

with a moderate number of fibroblasts.The periodontal ligament and cementumareas showed normal characteristics.

PDT treatment

At 7, 15 and 30 days, in most specimensin the ND and D (Fig. 5) Groups thatreceived the PDT treatment, the perio-dontal ligament was found to be intact,organized with parallel collagen fibresand lack of an inflammatory infiltrate.The bone tissue showed organizationwith thick bone trabeculae and no signsof resorption. The cementum surface didnot show resorption areas.

Table 1. Mean and standard deviation (M � SD) of body weight (g) in each group, treatment andperiod

Treatments Periods

Initial periods 7 days 15 days 30 days

Non-dexamethasone group (ND)SRP 245.85 � 4.18n 262.28 � 2.05n,&,w 282.85 � 1.46n,&,w 306.00 � 0.81n,&,w

TBO 247.42 � 5.88n 262 � 1.41n,&,w 284.28 � 1.11n,&,w 309.00 � 1.15n,&,w

PDT 247.28 � 5.31n 261.42 � 1.61n,&,w 284.14 � 2.03n,&,w 307.85 � 1.95n,&,w

N 90 30 30 30Dexamethasone (D)SRP 246.85 � 5.6n 218 � 1.29n,&,w 198.28 � 1.49n,&,w 177.14 � 1.34n,&,w

TBO 248.85 � 6.64n 219.28 � 1.11n,&,w 199.28 � 1.11n,&,w 178.28 � 1.49n,&,w

PDT 246.57 � 4.92n 219.14 � 1.21n,&,w 199.14 � 2.19n,&,w 178.28 � 1.11n,&,w

N 90 30 30 30

nSignificant difference among the experimental periods (initial, 7, 15 and 30 days) in the same group

and treatment (po0.05). ANOVA and Tukey’s tests.&Significant difference between groups in the same treatment and period (po0.05). ANOVA and

Tukey’s tests.wSignificant difference between groups and treatments in the same period (po0.05). ANOVA and

Tukey’s tests.

SRP, scaling and root planning; PDT, photodynamic therapy; TBO, Toluidine Blue-O.

Fig. 2. Mean and standard deviation (M � SD) of the radiographic data of the distancebetween the cemento-enamel junction and the alveolar bone crest (mm) on the mesial surfaceof the mandibular first molars in each group, treatment and period.



Histometric analysis

The histometric data are shown in Table2. In the ND Group, statistical analysisrevealed greater bone loss in the SRPtreatment (1.12 � 0.13, 0.90 � 0.27,1.00 � 0.16 mm2) when comparedwith the TBO treatment at 7 (0.67 �0.14 mm2) days. In comparison with thePDT treatment (0.54 � 0.06, 0.56 �0.13, 0.53 � 0.05 mm2), there was great-er bone loss in the SRP (po0.05) treat-ment in all experimental periods (Fig.6a). The furcation areas treated with PDTshowed a significant reduction of boneloss (po0.05), when compared with theTBO treatment (0.95 � 0.21 mm2) at 15days (Fig. 6b and c).

In the D Group, statistical analysis ofhistometric data showed greater boneloss in the SRP treatment at 7, 15 and30 days (Fig. 6d) (1.65 � 0.15, 1.71 �0.11, 1.5 � 0.25 mm2) when comparedwith the TBO treatment (0.74 � 0.12,1.06 � 0.10, 0.75 � 0.31 mm2) (Fig. 6e)and the PDT treatment (0.60 � 0.10,0.59 � 0.13, 0.57 � 0.10 mm2) (Fig. 6f).Histometric analysis demonstrated moresignificant bone loss in the TBO treat-ment compared with the PDT treatmentat 15 days (po0.05).

Histometrically, inter-group analysis(ND and D Groups) in the ND Group,treated with SRP (1.12 � 0.13, 1.00 �0.16 mm2), showed greater bone losscompared with the D Group, treated

with PDT, at 7 (0.60 � 0.10 mm2) and30 days (0.57 � 0.10 mm2).

Discussion

The aim of this study was to comparethe influence of PDT as an adjunctivetreatment on induced periodontitis inrats inhibited with dexamethasone. Toinvestigate the in vivo effect of PDT onperiodontal disease, we established theperiodontal disease model in rats causedby natural infection, simulating clinicalsituation conditions as closely as possi-ble. In the present study, the inducedperiodontal disease was characterizedby clinical signs of gingival inflamma-tion, as oedema, redness and attachmentloss of tooth gingival tissue. In dexa-methasone-inhibited animals (D), theclinical signs of gingival inflammationwere more exacerbated, characterizedas: greater bone loss in the furcationregion, connective tissue disorganiza-tion, discrete fibroblasts and an intenseinflammatory infiltrate in all experimen-tal periods, when compared with non-inhibited rats (ND).

The animals treated with this drugshowed lethargy, haematoma and alope-cia at the time they were killed. Further-more, there was a significant weightreduction in the present study; thisprobably occurred because the drugdecreased the gastrointestinal nutrientabsorption (Metzger et al. 2002). Thesealterations were already shown by otherauthors (Labelle & Schaffer 1966,Lipari et al. 1974), indicating a trendtowards immunossuppression and sys-temic alterations.

The results of the present study havealso demonstrated that group D animalsshowed greater bone loss in the furca-tion area, as well as more disorganizedconnective tissue when compared withgroup ND animals. These alterationswere described in other studies thathave also evaluated the effects of corti-coid on periodontal tissues (Lipari et al.1974, Cavagni et al. 2005).

On the other hand, a clinical studyhas not demonstrated the influence ofcorticosteroid therapy on the clinicalparameters of periodontal disease inpatients suffering from neurological dis-eases (Safkan & Knuuttila 1984). Theuse of high doses of corticoid leads to areduction in the number and activity ofthe osteoblasts and an increase in osteo-clast functions (Sattler et al. 2004). Italso reduces gastrointestinal calcium

Fig. 3. Photomicrograph illustrating the periodontal ligament area and bone loss in thefurcation region of the mandibular first molar in the D Group, treatment SRP 15 days – apicalthird into the furcation region – Areas of bone resorption with thin bone trabeculae (H&E;original magnification: a, �12.5; b, �40). H&E, hematoxylin and eosin SRP, scaling androot planing.

Fig. 4. (a) Photomicrograph illustrating the periodontal ligament area and bone loss in thefurcation region of the mandibular first molar in the D Group, treatment TBO 15 days – apicalthird into the furcation region – Areas of bone resorption with thin bone trabeculae anddisorganized connective tissue (H&E; original magnification: a, �12.5; b, �40). H&E,hematoxylin and eosin; TBO, Toluidine Blue-O.



absorption, which, in turn, results inlower calcium blood levels, and triggersPTH secretion that leads to systemicbone resorption (Suzuki et al. 1983).

However, another clinical study onliver transplantation patients has demon-strated that the doses of glucocorticoidshad no effect on alveolar bone loss,although there was an inverse relation-ship with the duration of treatment(Oettinger-Barak et al. 2007).

Corticoids can lead to a delay in thehealing process (Pessoa et al. 2004,Tenius et al. 2007) by decreased angio-genesis and capillary proliferation,which reduces blood flow (Leibovich& Ross 1975, Pierce & Lindskog 1989,Fassler et al. 1996, Durmus et al. 2003).

They also interfere in phagocytosis andantigen digestion, inhibiting macro-phage migrations and stabilizing lyso-some, preventing the release ofproteolytic enzymes. In addition, theymodify fibroblast functions, delayingtheir migration, damaging type-I andtype-II pro-collagen synthesis by mod-ifying mRNA and mitotic activity(Salmela 1981, Autio et al. 1994).

The number of researches related tothe PDT antimicrobial effects hasincreased. This therapy consists of anassociation of a photosensitizing agentwith a light source, being initially usedfor oncology treatment (Tomaselli et al.2001). Studies have shown favourableresults using PDT principles against

microorganisms involved in perio-dontitis (Yilmaz et al. 2002, Komeriket al. 2003, Sigusch et al. 2005, Qinet al. 2007) and periimplantitis (Shibliet al. 2003).

In the analysis of the histometricevaluation results, the ND and D groups,which received PDT treatment, showedless significant bone loss when comparedwith the animals treated only with SRP inall the experimental periods. The PDTtreatment has also shown effectiveness inbone loss reduction in both animalgroups when compared with TBO-treated animals, in a 15-day period.

In both groups (ND and D), radio-graphic examination showed that therewas significantly less bone in the ani-mals treated by PDT in all experimentalperiods than SRP and TBO after 15days, confirming the histometric results.

The results obtained in the presentstudy are in accordance with the litera-ture studies that showed PDT effective-ness in periodontal treatment both inanimals (Komerik et al. 2003, Siguschet al. 2005, Almeida et al. 2007, Qinet al. 2007) and in humans (Andersenet al. 2007, Braun et al. 2008). Resultsof recent studies in humans are contro-versial with respect to the beneficialeffects of PDT as an adjunctive therapyto non-surgery periodontal treatment(Braun et al. 2008, Christodoulideset al. 2008). Braun et al. (2008) showedthat, in patients with chronic perio-dontitis, the clinical outcomes of con-ventional subgingival debridement canbe improved by adjunctive PDT treat-ment. Another human study (Christo-doulides et al. 2008) showed that thePDT failed to result in an additionalimprovement in probing depth, clinicalattachment level and microbiologicchanges, but it resulted in a significantlyhigher reduction in bleeding scores.This discrepancy in the results may beexplained by the different methodolo-gies used in the studies such as: drugconcentrate ion, period of maintenanceof the drug within the tissue, time forbiological response, pH of the environ-ment (tissue/tooth interface), presenceof exudate, gingival fluid, mode andfrequency of drug application (irriga-tion, slow-release gel) (Wilson 2004).

The beneficial effect of PDT adjunc-tive to conventional mechanical treat-ment of periodontal disease, both indexamethasone-inhibited and in non-inhibited rats, was probably caused bythe photo-destructive effects on the dif-ferent periodontal pathogenic species,

Fig. 5. (a) Photomicrograph illustrating the periodontal ligament area and bone loss in thefurcation region of the mandibular first molar in the D Group, treatment PDT 15 days –coronary third into the furcation region – thick bone trabeculae without signs of resorption(H&E; original magnification: a, �12.5; b, �40). PDT, photodynamic therapy; H&E,hematoxylin and eosin.

Table 2. Mean and standard deviation (M � SD) of histometric data of bone loss area (mm2) inthe furcation region of the mandibular first molars in each group, treatment and period

Treatments Periods

7 days 15 days 30 days

Non-dexamethasone group (ND)SRP 1.12 � 0.13n,&,w 0.90 � 0.27n,& 1.00 � 0.16n,&,w

TBO 0.67 � 0.14w 0.95 � 0.21n,w 0.74 � 0.26w

PDT 0.54 � 0.06w 0.56 � 0.13w 0.53 � 0.05w

N 30 30 30Dexamethasone (D)SRP 1.65 � 0.15n,&,w 1.71 � 0.11n,&,w 1.50 � 0.25n,&,w

TBO 0.74 � 0.12w 1.06 � 0.10n,w 0.75 � 0.31PDT 0.60 � 0.10w 0.59 � 0.13 0.57 � 0.10w

N 30 30 30

nSignificant difference with PDT treatment in the same period and group (po0.05). ANOVA and

Tukey’s tests.&Significant difference between groups in the same treatment and period (po0.05). ANOVA and

Tukey’s tests.wSignificant difference between groups and treatments in the same period (po0.05). ANOVA and

Tukey’s tests.

SRP, scaling and root planning; PDT, photodynamic therapy; TBO, Toluidine Blue-O.



mediated by a type-I reaction (initiatedby superoxide, anionic hydroxyl or freeradicals) or by a type-II reaction(initiated by a singlet oxygen) (Ochsner1997, Wainwright 1998). These oxygen-reactive species are responsible for irre-versible damage on the bacterial cyto-plasmatic membrane, including proteinmodification, respiratory chain andnucleic acid alterations (Wainwright1998).

The isolated use of TBO (100 mg) ingroup ND rats also promoted less bone

loss in the furcation area when com-pared with SRP treatment, at 7 days, andin group D, in all experimental periods,different from the results found byKomerik et al. (2003), when usingTBO isolated with 0.01, 0.1 and 1 mg/ml (10, 100 and 1000mg/ml), where themorphometric analysis showed no sig-nificant difference in bone loss level.However, in the microbiologic analysis,a reduction of Porphyromonas gingival-lis was observed at a concentration of1 mg/ml (1000mg/ml) after 4 and 8 min.

of photosensitizing drug use. In thepresent study, the TBO treatment wascarried out after the conventionalmechanical therapy, which was notdone in that study (Komerik et al. 2003).

The TBO used as a photosensitizingdrug in PDT has rarely been evaluatedin vivo in periodontitis treatment(Komerik et al. 2003, Qin et al. 2007).Several studies have demonstrated thatgram-positive bacteria are susceptible tophotodynamic inactivation, but gram-negative bacteria (Malik et al. 1990,Usacheva et al. 2001) are significantlyresistant to many photosensitizers usedin PDT. In the present study, TBO wasused as a photosensitizer because itinteracts with LPS, present in the cellmembrane of gram-negative bacteria,more significantly than methylene blue,although the absorption band of themethylene blue is more resonant withthe emitted radiation of the laser used inthe present study (660 nm) (Usachevaet al. 2003, Wilson 2004).

There are reports in the literature onthe bactericide activity of TBO in lightabsence (Usacheva et al. 2001). Theresults of this study demonstrated thatthe furcation treated with PDT at 7 and30 days showed less bone loss than theTBO treatment in both groups (ND andD), but no statistically significant differ-ences were found. This can be explainedby an increased penetration of the druginto periodontal tissues, through theepithelium and connective tissue, aftera predicted removal of the sulcularepithelium following SRP procedures.These results could have occurred due toits interaction with LPS present in thecell membrane of gram-negative bacter-ia (Usacheva et al. 2003), along withbiofilm disorganization caused by SRP.

On the other hand, the TBO at 15days showed a relative increase in boneloss, but not a statistically significantdifference between 7 and 30 days. Thisresult is probably because the TBOconcentration was not so efficient onbiofilm reduction disorganized by SRPat 15 days, besides the inflammatoryresponse and bone resorption may bemore at 15 days. The bacterial endotox-ins, cytotoxins and other pathogenicsubstances are released from the biofilmand diffused into the adjacent soft tis-sues, where they elicit an inflammatoryresponse, resulting in tissue disruptionand degradation to periodontal tissue(Kornman et al. 1997, Page et al.1997). It was also evident in the presentstudy that group D animals, which

Fig. 6. Photomicrograph illustrating bone tissue in the furcation region of the mandibularfirst molar in the different Groups (ND and D) and treatments: (a) ND Group, treatment SRP15 days; (b) D Group, treatment SRP 15 days; (c) ND Group, treatment TBO 15 days; (d) DGroup, treatment TBO 15 days; (e) ND Group, treatment PDT 15 days; (f) D Group,treatment PDT 15 days (original magnification �12.5; Masson’s Trichromic). SRP, scalingand root planing; PDT, photodynamic therapy; TBO, Toluidine Blue-O.



received PDT treatment, showed lessbone loss compared with group ND ani-mals, which received only SRP treatment,at 7- and 30-day periods. The beneficialeffects of PDT in the periodontal diseasecould be explained not only by the localanti-microbial activity, described pre-viously, but also by the increased angio-genesis that supplies more oxygenation tothe area (Benstead & Moore 1989).

Another possible explanation for theresults could be the biomodulationaction of the low-intensity laser isolated.Studies have reported that the use of thissource accelerates bone repair, exerts ananti-inflammatory effect, favours the cel-lular chemotaxis (Houreld & Abrahamse2007) and promotes local vasodilatationand angiogenesis (Pessoa et al. 2004).Thus, it could provide increased oxygendiffusion through the tissue (Surinchaket al 1983, Al-Watban & Zhang 1997),which favours the repair processbecause the collagen secretion by fibro-blasts in the extracellular space occursonly in the presence of high rates ofoxygen pressure (Reenstra et al. 2001).

The systemic corticoid use has beenindicated in low and high doses formany treatments such as mucocutaneousand respiratory disease, tendinitis, bur-sitis, arthritis and cysts in general(American Academic of Periodontology2003); it is also used in all levels ofimmunotherapy, based on the need andregimen prescribed by the individualpractitioner (Vasanthan & Dallal2007). One of the side effects of thisdrug is the increased infection riskbecause of the inhibition effects ofcellular immunity, which could causemore severe periodontal damages(Lipari et al. 1974, Cavagni et al.2005), as demonstrated in this study.

Considering these facts, the applicationof alternative or adjunctive periodontaltherapeutics to SRP conventional treat-ment, such as the use of systemic anti-biotics, has been indicated, in spite of thedisadvantage of the development of bac-terial drug resistance (VanWinkelhoff etal. 1996). In this context, the use of localbactericide agents would be an alternativeadjunctive technique for periodontitistreatment. The concept of PDT is plausi-ble and could bring forth new therapyconcepts for periodontal disease, princi-pally in immunosuppressed patients, whopresent challenges for treatment strategies(Meisel & Kocher 2005).

The periodontal treatment has a locallimitation, such as effectiveness ofmechanical instrumentation in areas

that are difficult to access, e.g., thefurcation region. This limitation doesnot apply to the PDT as it is based ona photosensitizer associated with lightemission, such as laser irradiation.Another advantage of the PDT is thatit has no side effects, initiating itsactivity only when exposed to a lightsource and preventing resistant bacteriaspecies selection (Maisch 2007).

Within the limits of this study, it canbe concluded that PDT was effective asan SRP adjunctive treatment for boneloss reduction in induced experimentalperiodontitis when compared with non-surgical conventional treatment, both innormal rats and in systemic dexametha-sone-inhibited animals. The TBO useisolated is also effective as an adjunctiveperiodontal treatment for bone lossreduction in both normal rats and indexamethasone-inhibited rats. Theseencouraging results suggest that furtherexperimental and clinical studies mustbe carried out to determine effectiveparameters of irradiation and drug con-centration for clinical applicability inthe periodontal treatment of immunos-suppressed patients.

Acknowledgements

This work was conducted at the Depart-ment of Periodontology, Aracatuba Den-tal School, State University of Sao Paulo(UNESP) Aracatuba, Sao Paulo, Brazil.This study was financially supported byCAPES – Coordination for the Improve-ment of Higher Education Personnel(Brasilia, DF, Brazil) and CNPq -National Council for Scientific and Tech-nological Development (Brasilia, DF,Brazil). The authors would also like tothank Bruno Theodoro Luciano, fromInternational Relation Institute of BrasiliaUniversity, for the English review.

References

Adriaens, P. A., Edwards, C. A., DeBoever, J.

A. & Loesche, W. J. (1988) Ultrastructural

observations on bacterial invasion in cemen-

tum and radicular dentin of periodontally

diseased human teeth. Journal of Perio-

dontology 59, 493–503.

Almeida, J. M., Theodoro, L. H., Bosco, A. F.,

Nagata, M. J. H., Oshiiwa, M. & Garcia, V.

G. (2007) Influence of photodynamic therapy

on the development of ligature-induced

periodontitis in rats. Journal of Perio-


Almeida, J. M., Theodoro, L. H., Bosco, A. F.,

Nagata, M. J. H., Oshiiwa, M. & Garcia, V.

G. (2008) In vivo effect of photodynamic

therapy on periodontal bone loss in dental

furcations. Journal of Periodontology 79,

1081–1088.

Al-Watban, F. A. H. & Zhang, X. Y. (1997)

Comparison of wound healing process using

argon and krypton lasers. Journal of Clinical

Laser Medicine and Surgery 15, 209–215.

American Academic of Periodontology (2003)

Position paper: oral features of mucocuta-

neous disorders. Journal of Periodontology

74, 1545–1556.

Andersen, R., Loebel, N., Hammond, D. &

Wilson, M. (2007) Treatment of periodontal

disease by photodisinfection compared to

scaling and root planing. Clinical Dentistry

18, 34–38.

Autio, P., Oikarinen, A., Melkko, J., Risteli, J.

& Risteli, L. (1994) Systemic glucocorticoids

decrease the synthesis of type I and type III

collagen in human skin in vivo, whereas

isotretinoin treatment has little effect. British

Journal of Dermatology 131, 660–663.

Benstead, K. & Moore, J. V. (1989) Quantita-

tive histological changes in murine tail skin

following photodynamic therapy. British

Journal of Cancer 59, 503–509.

Braun, A., Dehn, C., Krause, F. & Jepsen, S.

(2008) Short-term clinical effects of adjunc-

tive antimicrobial photodynamic therapy in

periodontal treatment: a randomized clinical

trial. Journal of Clinical Periodontology 35,

877–884.

Breivik, T., Gundersen, Y., Osmundsen, H.,

Fonnum, F. & Opstad, P. K. (2006) Neonatal

dexamethasone and chronic tianeptine treat-

ment inhibit ligature-induced periodontitis in

adult rats. Journal of Periodontal Research

41, 23–32.

Cavagni, J., Soletti, A. C., Gaio, E. G. &

Rosing, C. K. (2005) The effect of dexa-

methasone in the pathogenesis of ligature-

induced periodontal disease in Wistar rats.

Brazilian Oral Research 19, 290–294.

Chan Lai, C. H. (2003) Bactericidal effects of

different laser wavelengths on periodonto-

pathic germs in photodynamic therapy.

Lasers in Medical Science 18, 51–55.

Christodoulides, N., Nikolidakis, D., Chondros,

P., Becker, J., Schwarz, F., Rossler, R. &

Sculean, A. (2008) Photodynamic therapy as

an adjunct to non-surgical periodontal treat-

ment: a randomized, controlled clinical trial.

Journal of Periodontology 79, 638–1644.

Derdilopoulou, F. V., Nonhoff, J., Neumann, K.

& Kielbassa, A. M. (2007) Microbiological

findings after periodontal therapy using cur-

ettes, Er:YAG laser, sonic, and ultrasonic

scalers. Journal of Clinical Periodontology

34, 588–598.

Durmus, M., Karaaslan, E., Ozturk, E., Gulec,

M., Iraz, M., Edali, N. & Ersoy, M. O. (2003)

The effects of single-dose dexamethasone on

wound healing in rats. Anesthesia and

Analgesia 97, 1377–1380.

Fassler, R., Sasaki, T., Timpl, R., Chu, M. L. &

Werner, S. (1996) Differential regulation of

fibulin, tenascin-C, and nidogen expression

during wound healing normal and glucocor-



ticoid-treated mice. Experiments in Cell

Research 222, 111–116.

Faveri, M., Gursky, L. C., Feres, M., Shibli, J.

A., Salvador, S. L. & Figueiredo, L. C. (2006)

Scaling and root planing and chlorhexidine

mouthrinses in the treatment of chronic perio-

dontitis: a randomized, placebo-controlled

clinical trial. Journal of Clinical Perio-


Graves, D. T., Fine, D., Teng, Y-T. A., Van

Dyke, T. E. & Hajishengallis, G. (2008) The

use of rodent models to investigate host-

bacteria interactions related to periodontal

disease. Journal of Clinical Periodontology

35, 89–105.

Holzhausen, M., Rossa Junior, C., Marcantonio

Junior, E., Nassar, P. O., Spolidorio, D. M. &

Spolidorio, L. C. (2002) Effect of selective

cyclooxygenase-2 inhibition on the develop-

ment of ligature-induced periodontitis in rats.

Journal of Periodontology 73, 1030–1036.

Houreld, N. & Abrahamse, H. (2007) In vitro

exposure of wounded diabetic fibroblast cells

to a helium-neon laser at 5 and 16 J/cm2.

Photomedicine and Laser Surgery 25, 78–84.

Kaldahl, W. B., Kalkwarf, K. L. & Patil, K. D.

(1993) A review of longitudinal studies that

compared periodontal therapies. Journal of

Periodontology 64, 243–253.

Kamma, J. J. & Slots, J. (2003) Herpes virus

bacterial interaction in aggressive perio-

dontitis. Journal of Clinical Periodontology

30, 420–426.

Kaner, D., Bernimoulin, J. P., Hopfenmuller,

W., Kleber, B. M. & Friedmann, A. (2007)

Controlled-delivery chlorhexidine chip ver-

sus amoxicillin/metronidazole as adjunctive

antimicrobial therapy for generalized aggres-

sive periodontitis: a randomized controlled

clinical trial. Journal of Clinical Perio-


Komerik, N., Nakanishi, H., MacRobert, A. J.,

Henderson, B., Speight, P. & Wilson, M.

(2003) In vivo killing of porphyromonas

gingivalis by toluidine blue mediated photo-

sensitization in an animal model. Antimicro-

bial Agents Chemotherapy 47, 932–940.

Kornman, K. S., Page, R. C. & Tonetti, M. S.

(1997) The host response to the microbial

challenge in periodontitis: assembling the

players. Periodontology 2000 14, 33–53.

Labelle, R. E. & Schaffer, E. M. (1966) The

effects of cortisone and induced local factors

on the periodontium of the albino rat. Journal

of Periodontology 37, 483–490.

Lee, M. K., Ide, M., Coward, P. Y. & Wilson, R.

F. (2008) Effect of ultrasonic debridement

using a chlorhexidine irrigant on circulating

levels of lipopolysaccharides and interleukin-

6. Journal of Clinical Periodontology 35,

415–419.

Leibovich, S. J. & Ross, R. (1975) The role of

the macrophage in wound repair. A study

with hydrocortisone and antimacrophage ser-

um. American Journal of Pathology 78, 71–

100.

Lipari, W. A., Blake, L. C. & Zipkin, I. (1974)

Preferential response of the periodontal appa-

ratus and the epiphyseal plate to hydrocorti-

sone and fluoride in the rat. Journal of

Periodontology 45, 879–889.

Maisch, T. (2007) Anti-microbial photody-

namic therapy: useful in the future? Laser

in Medical Science 22, 83–91.

Malik, Z., Hanania, J. & Nitzan, Z. (1990)

Bactericidal effects of photoactivated por-

phyrins – an alternative approach to antimi-

crobial drugs. Journal of Photochemistry and

Photobiology B 5, 281–293.

Matia, J. I., Bissada, N. F., Maybury, J. E. &

Ricchetti, P. (1986) Efficiency of scaling of

the molar furcation area with and without

surgical access. International Journal of

Periodontics and Restorative Dentistry 38,

24–35.

Meisel, P. & Kocher, T. (2005) Photodynamic

therapy for periodontal diseases: state of the

art. Journal of Photochemistry and Photo-

biology B 79, 159–170.

Metzger, Z., Klein, H., Klein, A. & Tagger, M.

(2002) Periapical lesion development in rats

inhibited by dexamethasone. Journal of

Endodontics 28, 643–645.

Needleman, I., Suvan, J., Gilthorpe, M. S.,

Tucker, R., St George, G., Giannobile, W.,

Tonetti, M. & Jarvis, M. (2007) A rando-

mized-controlled trial of low-dose doxycy-

cline for periodontitis in smokers. Journal of

Clinical Periodontology 34, 325–333.

Nociti, F. H. Jr., Nogueira-Filho, G. R., Primo,

M. T., Machado, M. A., Tramontina, V. A.,

Barros, S. P. & Sallum, E. A. (2000) The

influence of nicotine on the bone loss rate in

ligature-induced periodontitis. A histometric

study in rats. Journal of Periodontology 71,

1460–1464.

Ochsner, M. (1997) Photophysical and photo-

biological processes in the photodynamic

therapy of tumours. Journal of Photochemis-

try and Photobiology B 39, 1–18.

Oettinger-Barak, O., Segal, E., Machtei, E. E.,

Barak, S., Baruch, Y. & Ish-Shalom, S.

(2007) Alveolar bone loss in liver transplan-

tation patients: relationship with prolonged

steroid treatment and parathyroid hormone

levels. Journal of Clinical Periodontology

34, 1039–1045.

Page, R. C., Offenbacher, S., Schroeder, H. E.,

Seymour, G. J. & Kornman, K. S. (1997)

Advances in the pathogenesis of perio-

dontitis: summary of developments, clinical

implications and future directions. Perio-

dontology 2000 14, 216–248.

Pessoa, E. S., Melhado, R. M., Theodoro, L. H.

& Garcia, V. G. (2004) A histological assess-

ment of the influence of low-intensity laser

therapy on wound healing in steroid-treated

animals. Photomedicine and Laser Surgery

22, 199–204.

Pierce, A. M. & Lindskog, S. (1989) Early

responses by osteoclasts in vivo and dentino-

clasts in vitro to corticosteroids. Journal of

Submicroscopic Cytology and Pathology 21,

501–508.

Qin, Y. L., Luan, X. L., Bi, L. J., Sheng, Q.,

Zhou, C. N. & Zhang, Z. G. (2007) Compar-

ison of toluidine blue-mediated photody-

namic therapy and conventional scaling

treatment for periodontitis in rats. Journal

of Periodontology Research 43, 162–167.

Reenstra, W. R., Veves, A., Orlow, D. & Buras,

J. A. (2001) Decrease proliferation and cel-

lular signaling in primary dermal fibroblasts

derived from diabetics versus non diabetic

sibling controls. Academic Emergency Med-

icine 8, 519.

Safkan, B. & Knuuttila, M. (1984) Corticoster-

oid therapy and periodontal disease. Journal

of Clinical Periodontology 11, 515–522.

Salmela, K. (1981) Comparison of the effects

of methylprednisolone and hydrocortisone

on granulation tissue development: a experi-

mental study in rat. Scandinavian Journal

of Plastics Reconstructive Surgery 15,

87–91.

Sarkar, S. & Wilson, M. (1993) Lethal photo-

sensitization of bacteria in subgingival plaque

from patients with chronic periodontitis.

Journal of Periodontal Research 28, 204–

210.

Sattler, A. M., Schoppet, M., Schaefer, J. R. &

Hof-bauer, L. C. (2004) Novel aspects on

RANK ligand and osteoprotegrin in osteo-

porosis and vascular disease. Calcified Tissue

International 74, 103–106.

Seymour, R. A. (2006) Effects of medications

on the periodontal tissues in health and dis-

ease. Periodontology 2000 40, 120–129.

Shibli, J. A., Martins, M. C., Theodoro, L. H.,

Lotufo, R. F., Garcia, V. G & Marcantonio,

E. J. (2003) Lethal photosensitization in

microbiological treatment of ligature-induced

peri-implantitis: a preliminary study in dogs.

Journal of Oral Science 45, 17–23.

Sigusch, B. W., Pfitzner, A., Albrecht, V. &

Glockmann, E. (2005) Efficacy of photody-

namic therapy on inflammatory signs and two

selected periodontopathogenic species in a

beagle dog model. Journal of Periodontology

76, 1100–1105.

Surinchak, J. S., Alago, M. L., Bellamy, R. F.,

Stuck, B. E. & Belkin, M. (1983) Effect of

low-level energy laser on the healing of full-

tickness skin defects. Lasers in Surgery and

Medicine 2, 267–274.

Suzuki, Y., Ichikawa, Y., Saito, E. & Homma,

M. (1983) Importance of increased urinary

calcium excretion in the development of

secondary hyperparathyroidism of patients

under glucocorticoid therapy. Metabolism

32, 151–156.

Tenius, F. P., Biondo-Simoes, M. L. P. & Ioshii,

S. O. (2007) Effects of chronic use of dex-

amethasone on cutaneous wound healing in

rats. An Bras Dermatol 82, 141–149.

Tomaselli, F., Maier, A., Sankin, O., Anegg, U.,

Stranzl, U., Pinter, H., Kapp, K. & Smolle-

Juttner, F. M. (2001) Acute effects of com-

bined photodynamic therapy and hyperbaric

oxygeneration in lung cancer – a clinical pilot

study. Lasers in Surgery in Medicine 28,

399–403.

Usacheva, M., Teicher, T. M. C. & Biel, M. A.

(2001) Comparison of the methylene blue

and toluidine blue photobactericidal efficacy

against gram-positive and gram-negative

microorganisms. Lasers in Surgery and Med-

icine 29, 165–173.



Usacheva, M., Teichert, M. C. & Biel, M. A.

(2003) The interaction of lipopolysaccharides

with phenothiazine dyes. Laser in Surgery

and Medicine 33, 311–319.

VanWinkelhoff, A. J., Rams, T. E. & Slots, J.

(1996) Systemic antibiotic therapy in perio-

dontics. Periodontology 2000 10, 45–78.

Vasanthan, A. & Dallal, N. (2007) Periodontal

treatment considerations for cell transplant

and organ transplant patients. Periodontology

2000 44, 82–102.

Wainwright, M. (1998) Photodynamic antimi-

crobial chemotherapy. Journal of Antimicro-

bial Chemotherarapy 42, 13–28.

Wilson, M. (2004) Lethal photosensitisation of

oral bacteria and its potential application in

the photodynamic therapy of oral infections.

Photochemical and Photobiological Science

3, 412–418.

Yilmaz, S., Kuru, B., Kuru, L., Noyan, U.,

Argun, D. & Kadir, T. (2002) Effect of

galium arsenide diode laser on human perio-

dontal disease: a microbiological and clinical

study. Lasers in Surgery and Medicine 30,

60–66.

Zanin, I. C., Goncalves, R. B., Junior, A. B.,

Hope, C. K. & Pratten, J. (2005) Suscept-

ibility of streptococcus mutans biofilms to

photodynamic therapy: an in vitro study.

Journal of Antimicrobial Chemotherapy 56,

324–330.

Address:

Valdir Gouveia Garcia

Faculdade de Odontologia de Aracatuba-

UNESP:

Rua Jose Bonifacio 1193, Centro.

CEP: 16050-300 Aracatuba, SP

Brazil

E-mail: [email protected]

Clinical Relevance

Scientific rationale for the study:Prolonged therapy with corticoidsmay be a risk factor for periodontaldisease. In such cases, only the SRPcan fail in periodontal treatment. ThePDT has showed satisfactory resultswith an adjunctive periodontal treat-

ment, but its application in immuno-suppressed patients has not beenreported in the literature.Principal findings: The PDT waseffective as an SRP adjunctive treat-ment for bone loss reduction ininduced experimental periodontitis

both in normal rats and in systemicdexamethasone-inhibited animals.Practical implications: The PDTmight provide further treatment pos-sibilities to non-surgical conven-tional treatment in immunosuppressedpatients.



Treatment of experimental periodontal disease by photodynamic therapy in immunosuppressed rats

Documents

Transcript of Treatment of experimental periodontal disease by photodynamic therapy in immunosuppressed rats