New Irradiation Method with Indocyanine Green-Loaded Nanospheres for Inactivating Periodontal Pathogens.

Yasuyuki Sasaki,Akio Mitani,Mitsuo Fukuda,Tasuku Ohno,Eisaku Nishida,Hiromitsu Yamamoto,Takeshi Kikuchi,Takeki Fujimura,Kosuke Okada,Yuki Iwamura,Jun-Ichiro Hayashi,Genta Yamamoto

doi:10.3390/ijms18010154

Yasuyuki Sasaki, Akio Mitani + Show 10 more

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https://doi.org/10.3390/ijms18010154

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Abstract

Antimicrobial photodynamic therapy (aPDT) has been proposed as an adjunctive strategy for periodontitis treatments. However, use of aPDT for periodontal treatment is complicated by the difficulty in accessing morphologically complex lesions such as furcation involvement, which the irradiation beam (which is targeted parallel to the tooth axis into the periodontal pocket) cannot access directly. The aim of this study was to validate a modified aPDT method that photosensitizes indocyanine green-loaded nanospheres through the gingivae from outside the pocket using a diode laser. To establish this trans-gingival irradiation method, we built an in vitro aPDT model using a substitution for gingivae. Irradiation conditions and the cooling method were optimized before the bactericidal effects on Porphyromonas gingivalis were investigated. The permeable energy through the gingival model at irradiation conditions of 2 W output power in a 50% duty cycle was comparable with the transmitted energy of conventional irradiation. Intermittent irradiation with air cooling limited the temperature increase in the gingival model to 2.75 °C. The aPDT group showed significant bactericidal effects, with reductions in colony-forming units of 99.99% after 5 min of irradiation. This effect of aPDT against a periodontal pathogen demonstrates the validity of trans-gingival irradiation for periodontal treatment.

Highlights

Periodontitis is caused by anaerobic bacteria, which form a biofilm on tooth surfaces or in the periodontal pocket
Removal of the biofilm and elimination of periodontal pathogens from the periodontal pocket is the main purpose of treatment for this disease [2]
Complete eradication of pathogenic bacteria from areas that are inaccessible to periodontal instruments is difficult

Summary

Introduction

Periodontitis is caused by anaerobic bacteria, which form a biofilm on tooth surfaces or in the periodontal pocket. These actions provoke an excessive and aggressive immune reaction in the host, and cause collateral damage to periodontal tissues [1]. Removal of the biofilm and elimination of periodontal pathogens from the periodontal pocket is the main purpose of treatment for this disease [2]. Scaling and root-planing (SRP) is a non-surgical method of mechanical debridement to eliminate calculus, plaque, and contaminated root cementum/dentine from the periodontal pocket and usually results in significant clinical improvement. Complete eradication of pathogenic bacteria from areas that are inaccessible to periodontal instruments is difficult. Ihnasabreeecnensthsotwudnyt,owbee evfafelicdtaivteed evtheen apgrianincisptlreesoifstuansitnbgacatPeDriaTl sfoprecpieesri[o1d5o,1n6t]a.lInthaerraepceyn. tWsteudeym, pwleoyveadlidaante8d10th-nemprdinicoidpelelaosfeursiwnigth aPinDdTocfyoarnpienreiodgorneetanl-ltohaedraepdy.nWaneoesmphpeloreysedcaonat8e1d0-nwmithdiocdheitloassaenr w(iItChGin-Ndoacnyoa/cn)inetogredeenm-loonasdteradte nannaonsop-shpehreesriczoaattieodn,wpiothsictihvietoscahnar(gICinGg-Nofanthoe/cc)htiotodseamn ocnosattriantge noaf ntoh-espphheortiozasetinosni,tipzoers,itaivnedchreasrugilntagnt ofimthpercohvietodsaanntciboaactitnegriaolf ethffeecpthsootfoasePnDsTiti[z1e7r,].and resultant improved antibacterial effects of aPDT [17]

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