光催化劑在牙科研究中的應用進展

野村義明　花田信弘　劉艷飛

摘要：光催化劑有兩個主要作用：有機化合物的降解和超親水性，這些作用使其具有抗菌和自清潔的效果。目前，光催化劑已經被應用于醫學臨床實踐。兩種主要的口腔疾病（齲齒和牙周病）影響著全球幾十億人，而治療口腔疾病則可以直接接觸到口腔內的病灶。牙科領域會使用到各種先進的牙科材料。因此，光催化劑可以成為牙科臨床實踐的有用工具。本文綜述了光催化劑在牙科研究中的應用研究，并展望了光催化劑在牙科研究中的未來前景。關鍵詞：光催化劑；牙科臨床實踐；牙科研究；牙科材料

中圖分類號：O 644文獻標志碼：A

Recent advances of application of photocatalyst for dental research

NOMURA Yoshiaki ， HANADA Nobuhiro， LIU Yanfei

（Institute of Photochemistry and Photocatalyst， University of Shanghai for Science and Technology， Shanghai 200093， China）

Abstract： Photocatalysthastwomajoreffects：degradationoforganiccompoundsandsuperhydrophilicity. These effects lead to the antimicrobial and self-cleaning effects. Photocatalyst hasbeenappliedformedicalclinicalpractices.Twomajororaldiseases（dentalcariesandperiodontaldisease） globally influence on several billons of people. Treatment of oral diseases allows direct accesstolesionsintheoralcavity.Andtherearevariousadvanceddentalmaterialsindentistry.Therefore，photocatalystcanbeusefultoolfordentalclinicalpractice.Theaimthisreportistosummarizetheresearchofapplicationofphotocatalystfordentalresearchandtofindoutthefutureprospectiveforphotocatalyst to dentistry.

Keywords： photocatalyst; dental clinical practice; dental research; dental materials

Dr.Fujishima，presidentofInstituteofPhotochemistryandPhotocatalystofUniversityofShanghaiforScienceandTechnology，foundoutthephotocatalyticreactionmechanism [1].Thisphenomenonhastwomajoreffects：degradationoforganic compounds and superhydrophilicity.

Photocatalystisknowntodecomposevariousorganiccompoundsunderilluminationbygeneratingvariousradicals.Organiccompoundsadsorbedonthesurface can be self-cleaned by the photodecomposition.In addition， super hydrophilic effect makes the organiccompoundshardtoattachthesurface.Photocatalystshave multiple applications in air purifiers， paints， and self-cleaningcoatingsformedicaldevicessuchas catheters，aswellasintheeliminationof microbes. Photocatalystisalsoappliedtodentalresearchand clinical dental practice.

Dentalcariesandperiodontaldiseasesaretwo majororaldiseases. Globally，itisestimatedthat 2 billion people suffer from dental caries of permanent teethand 514 millionchildrensufferfromcariesof primaryteeth. Prevalenceof themainoraldiseases continuestoincreasegloballywithgrowing urbanizationandchangesinlivingconditions. Periodontaldiseaseaffectsthetissuesthatboth surroundandsupporttheteeth. Thediseaseis characterized by bleeding orswollen gums， pain and sometimes bad breath. Severe periodontal diseases are estimatedtoaffectaround 19% of theglobaladult population，representingmorethan 1 billioncases worldwide[2].

These two major oral diseases are affected by oral pathogenicbacteria. Inhumanbody，therearetwo major bacterial flora： intestinal bacterial flora and oral bacterialflora. Anoral microbiomeconsistsof more than 700 speciesofbacteria [3-9]. Tocontroloral bacterial flora lead to the prevention of oral diseases， treatmentoforaldiseasesallowsdirectaccessto lesionsintheoralcavity，andtherearevarious advanceddentalmaterialsindentistry. Therefore， photocatalyst can be useful tool to control oral bacterial flora. Finally， photocatalyst can be useful tool for the prevention of oral diseases.

The aim of this report is to summarize the research of application of photocatalyst for dental research and to find out the future prospective for photocatalyst to dentistry.

1 Martials and Methods

1.1 Search Strategy

Electronicdatabase，PubMedwassearchedfor eligible studies. Abstracts were reviewed， and full-text articleswereinspectedforinclusioncriteria. The referencelistsfromreviewedstudieswerealso examined to seek additional sources.

Keywordsearchtermsusingmedicalsubjectheadings and text words included. Search details were asfollows：（“photocatalyst ”[MeSHterms] or “photocatalyst ”[all fields]） and （（“dental ”[MeSH Terms] or “dental ”[all fields]） or （“oral ”[MeSH terms] or “oral ”[all fields]））（“photocatalyst ”[all Fields]） and （（“dental ”[all fields]） or “oral ”[allfields]））. Studies were included if they were written in English.

1.2 Study Selection

An initial search for studies using saliva for the evaluation of periodontitis generated 46 articles. During thepreliminaryanalysis， 14 studieswereexcluded because they were not concerned with dental research. After reviewed thearticles， two reviewarticles were removed. Finally， 29 articleswereindependently reviewed and summarized by two authors （Nomura Y. and Hanada N.）.

1.3 Classification

According to the review of the abstracts full-text articles，articleswereclassifiedbasedonthe applicationofphotocatalystfordentalmaterials， clinical dental practice or dental research into 3 major categories： antibacterialeffectonnoveldental materials， dental materials （implant， resin， others and dentalpractice （toothwhitening/bleaching）. After classification， the articles were summarized.

2 Results

Atotalof 46 articleswerehitonthePubMed database， 29 were included for the review. According totheclassificationsdescribedinmaterialsand methods， 6 articleswereclassifiedintoantibacterial effect of novel dental materials， 9 were implant， 4 were resin， 3 were other dental materials and 5 were tooth whitening/bleaching.

2.1 Antibacterial effect of novel dental materials Sevenarticlesweremettherequirementfor antibacterial effect of novel dental materials. Without one article[10]， photocatalysis activity leaded resulted in anti-microbial activity （Tab.1）. One article investigated thechangesof bacterialinnercellmoleculeswhich leaded the mechanism of the antimicrobial activity of photocatalyst[11]. Onearticlehadshownthatcombinationofhydroxyapatite，whichisthemajor componentoftoothenamel，andTiO2 actedforremineralizationfor surface[12]（Tab.1）.

2.2 Applicationofphotocatalystfordental materials

2.2.1 Dental implant

Dental implants involve the insertion of synthetic roots into the jawbone where teeth have been lost and thefabricationof artificialteeththereon. Themajor materials used for the dental implant is now titanium. At initialstage， antibacterial activity of photocatalyst coating or surface treatment of titanium were confirm- ed [16-19]. Otherthanantimicrobialactivity，effectof photocatalysis on bone formation was also investigat- ed [20-24]（Tab.2）.

2.2.2 Resin

Poly methyl methacrylate is often used in clinical dentalpractice. Itusedasdenturebase，provisional restoration，artificialteethondenturebaseetc. Two studiesinvestigatedtheantimicrobialeffectof photocatalyst on resin [25-28]. One article investigated the effectofphotocatalystonthecuringreaction [26]（Tab.3）.

2.2.3 Other dental materials

By the tooth extraction， wearing ill fit denture， or inflamed gum disease， the gum attached to the denturesurfacebecomessensitive. Tissueconditioneris temporally used on the mucosal surface of the denture until the inflammation of gum is healing. Two articles investigatedtheantimicrobialeffectof photocatalyst applyingtissueconditioners[29-30]. Onearticle investigated the effect of the photocatalyst containing toothpaste[31]（Tab.4）.

2.3 Dental clinical procedures

Fordentalclinicalprocedures， 6 articleswere applied photocatalyst for whitening/bleaching （Tab.5）. Teeth whitening involves bleaching teeth to make them lighter. Itcan't make teeth brilliant white， butitcan lighten the existing color by several shades. At initial stage，threearticlesinvestigatedthedegradationof pigments by photocatalyst[32-34]. Then materials used for the teeth bleaching were modified[35-36].

3 Discussion

Inthisarticle，wesystematicallyreviewedthe articleconcerned with photocatalystapplyingfor the dental research and clinical practice.

In the treatment of oral diseases， lesions in oralcavity? can? be? directly? accessible.? Complex? drugdelivery? systems? are? not? necessary.? In? addition，dentistry? has? various? advanced? dental? materials.Restorative? and? prosthetic? treatments? are? major? dentalpractice.? Fine? dental? materials? are? indispensable? forthese? treatments.? These? two? major? characteristics? ofdentistry? make? the? application? of? novel? materials? forthe dental treatment easy. All of the articles reviewed inthis? study? are? concerned? with? the? dental? materials.Among the 29 articles reviewed in this report， 10 wereconcerned with dental implant.

Dental? implant，? which? is? an? artificial? root? of? theteeth，? consisted? of? titanium.? Therefore，? applicationphotocatalyst? for? the? surface? of? the? implant? istechnically easy. Biocompatibility and antimicrobe areimportant? factors? for? the? prognosis? of? dental? implant.The prognosis of dental implant mainly depends on theinfection? in? the? gap? between? dental? implant? andsupportive? tissue[37].? It? is? called? as? peri-implantitis? orperi-implant? disease.? Peri-implantitis? has? become? aglobal burden[38-39]. Prevalence of peri-implantitis were1%? to? 47% [40] ， 29.48%[41]or? 80%[42].? Eight? articlesout? of? ten? concerned? with? dental? implant? wereinvestigated? antimicrobial? effect? of? the? photocatalyst.Photocatalyst? effectively? reduced? bacterial? adhesion[17-19，21，24]，? biofilm? formation[16].? After? insertion? ofdental? implant? into? the? jaw? bone，? irradiation? to? obtainthe? photocatalystic? effect? is? impossible.? However，complete sterilization is indispensable during the dentalimplant surgery. Bacterial contamination largely effectson? the? prognosis? of? dental? implant[43].? Even? the? sorttime? periods，? contentious? antimicrobial? effect? ofphotocatalyst? may? effectively? work? for? the? preventionof contamination during the surgery.

Four? articles? reported? the? application? ofphotocatalyst? for? resin.? In? dental? practice，? PMMA? isfrequently used. One of the characteristics of PMMA is hydrophilia. Absorbency of complex oral fluid makes theprothesisandprovisionalrestorationsfilthy. In addition， microbes colonize on the surface of PMMA. Coating photocatalyst on the surface of resin effectively works for the sanitization of the dental materials [27-28]. Inaddition，itpromotesthecuringreactionsof PMMA[26].

Thereweretwoarticlesconcernedwithtissue conditioner [29-30]. Tissue conditioner is a denture lining material for inflated gum that support the denture. The majorcomponentof tissueconditionerisageltype PMMA. Even through application of tissue conditioner is temporal， it is easy to be staining， coloration， stinking andmoulding. Includingphotocatalystintissue conditionerhasantifungaleffect. Untilthe inflammationofgumheeling，patientsvisitdental clinic. Irradiation can be applicable during the patient visitdentalclinics. Effectofphotocatalystmaybe desirable to keep tissue conditioner clean.

Whitening/bleaching the discolored teeth improve the quality of life of the patients[44]. Hydrogen peroxide isthemajorreagentforwhitening/bleaching. Photocatalystenhancestheremovalof thestainon toothsurface[32-34]. Itisalsoeffectivefordiscolored teethbytetracycline[35]. Takingtetracyclineduring fetusorinfantagepigmentssedimentinnerteeth[7]. Photocatalyst containing whitening/bleaching materials are already packaged and commercially available. As UV irradiation is incapable for human oral cavity， the research concerning whitening/bleaching were focused on the safety and effectiveness of the light source[32-34].

Several articles with application of photocatalystfordentalresearchanddentalclinicalpractice. However， information is not enough. Photocatalyst is a usefultoolfordentalclinicalpractice. Forthe application of photocatalyst for dental clinical practice， accumulationof evidencesandcommercializationof dental materials are necessary.

References

[1] FUJISHIMA A， HONDA K. Electrochemical photolysis of wateratasemiconductorelectrode[J]. Nature， 1972， 238（5358）：37–38.

[2] WHO. Oralhealth[EB/OL].[2022-11-18]. https：//www. who.int/news-room/fact-sheets/detail/oral-health#：～：text= Globally%2C%20an%20estimated%202%20billion，and%20changes%20in%20living%20conditions.

[3] AAS J A， PASTER B J， STOKES L N， et al. Defining the normalbacterialfloraof theoralcavity[J]. Journalof Clinical Microbiology， 2005， 43（11）：5721–5732.

[4] NOMURA Y，INAI Y，SHIMPO Y，etal. Incidenceof postoperative pneumonia and oral microbiome for patients withcanceroperation[J]. AppliedSciences， 2022， 12（6）：2920.

[5] SHIMPO Y， NOMURA Y， SEKIYA T， et al. Effects of the dental caries preventive procedure on the white spot lesions during orthodontic treatment —an open label randomized controlledtrial[J]. JournalofClinicalMedicine， 2022， 11（3）：854.

[6] NOMURAY，OKADAA，HANADAN. Future prospectiveoforalmicrobiomeresearch[J]. Applied Sciences， 2022， 12（1）：55.

[7] NOMURA Y， KAKUTA E， KANEKO N， et al. The oral microbiome of healthy Japanese people at the age of 90[J]. Applied Sciences， 2020， 10（18）：6450.

[8] NOMURAY，KAKUTAE，OKADAA，etal. Oral microbiomeinfourfemalecentenarians[J]. Applied Sciences， 2020， 10（15）：5312.

[9] NOMURA Y， OTSUKA R， HASEGAWA R， et al. Oral microbiomeofchildrenlivinginanisolatedareain Myanmar[J]. InternationalJournalofEnvironmental Research and Public Health， 2020， 17（11）：4033.

[10] CHOI J Y， KIM K H， CHOY K C， et al. Photocatalytic antibacterial effect of TiO2 film formed on Ti and TiAg exposedtoLactobacillusacidophilus[J]. JournalofBiomedicalMaterialsResearch，PartB. AppliedBiomaterials， 2007， 80B（2）：353–359.

[11] AL-SERWI R H， EL-SHERBINY M， KUMAR T V A， et al. Molecular docking and green synthesis of bioinorganic TiO2 nanoparticlesagainstE. coliandS. aureus[J]. BioinorganicChemistryandApplications， 2022， 2022：1142727.

[12] WANG R X， JIAC H， ZHENG N N，etal. Effectsof photodynamictherapyonStreptococcusmutansand enamelremineralizationofmultifunctionalTiO2-HAP compositenanomaterials[J]. Photodiagnosisand PhotodynamicTherapy， 2022，doi：10.1016/j.pdpdt.2022.103141.

[13] WESTASE，HAYASHIM，CECCHINATOF，etal. Bactericidaleffectofphotocatalytically-active nanostructured TiO2 surfaces on biofilmsoraoftheearlylcolonizer， Streptococcusoralis[J]. Journalof Biomedical Materials Research Part A， 2017， 105（8）：2321–2328.

[14] GUOJN，ZHOUJM，SUNZ，etal. Enhanced photocatalyticandantibacterialactivityofacridinium-graftedg-C3N4 with broad-spectrumlightabsorptionfor antimicrobial photocatalytic therapy[J]. Acta Biomaterialia， 2022， 146：370–384.

[15] KUNNAMAREDDY M， GANESANS， HATAMLEH A A，etal. Enhancementinthevisiblelightinduced photocatalyticandantibacterialpropertiesoftitanium dioxide codoped with cobalt and sulfur[J]. Environmental Research， 2023， 216（Pt 3）：114705.

[16] SUKETAN，SAWASET，KITAURAH，etal. An antibacterialsurfaceondentalimplants，basedonthe photocatalyticbactericidaleffect[J]. ClinicalImplant Dentistry and Related Research， 2005， 7（2）：105–111.

[17] AHNSJ，HANJS，LIMBS，etal. Comparisonof ultravioletlight-induced photocatalytic bactericidaleffect onmodifiedtitaniumimplantsurfaces[J]. International Journal of Oral and Maxillofacial Implants， 2011， 26（1）：39–44.

[18] KAWANO T， PRANANINGRUM W， ISHIDA Y， et al. Blue-violet laser modification of Titania treated titanium： antibacterialandosteo-inductiveeffects[J]. PLoSOne， 2013， 8（12）： e84327.

[19] YAMADA Y， YAMADA M， UEDA T， et al. Reduction of biofilmformationontitaniumsurfacewith ultraviolet-C pre-irradiation[J]. JournalofBiomaterialsApplications， 2014， 29（2）：161–171.

[20] HIRAKAWAY，JIMBOR，SHIBATAY，etal. Accelerated bone formation on photo-induced hydrophilic titaniumimplants： anexperimentalstudyinthedog mandible[J]. ClinicalOralImplantsResearch， 2013， 24Suppl A100：139–144.

[21] YENIYOL S， MUTLU I， HE Z M， et al. Photocatalytical antibacterial activity of mixed-phase TiO2 nanocomposite thinfilmsagainstAggregatibacteractinomycetemcomitans[J]. BioMed Research International， 2015， 2015：705871.

[22] NAGAY B E， DINI C， CORDEIRO J M， et al. Visible- light-inducedphotocatalyticandantibacterialactivityof TiO2 codoped with nitrogen and bismuth： new perspectives tocontrolimplant-biofilm-relateddiseases[J]. ACS AppliedMaterials & Interfaces， 2019， 11（20）：18186–18202.

[23] VENKEIA，UNGV?RIK，E?RDEGHG，etal. Photocatalyticenhancementofantibacterialeffectsof photoreactive nanohybrid films in an in vitro Streptococcus mitismodel[J]. ArchivesofOralBiology， 2020， 117：104837.

[24] JANANI B， BALAKRISHNARAJA R， ELGORBAN A M， etal. Eco-friendlycubic-ZnScoupledCu7S4 spineson chitosanmatrix： unravellingdefect-engineered nanoplatformforthephotodegradationofp- chlorophenol[J]. Journalof EnvironmentalManagement， 2023， 326（Pt A）：116615.

[25] CHENG Y L， SAKAI T， MOROI R， et al. Self-cleaningabilityofaphotocatalyst-containingdenturebase material[J]. DentalMaterialsJournal， 2008， 27（2）：179–186.

[26] INGROSSO C， ESPOSITO CORCIONE C， STRIANI R， et al. UV-curablenanocompositebasedonmethacrylic- siloxane resin and surface-modified TiO2 nanocrystals[J]. ACSAppliedMaterials & Interfaces， 2015， 7（28）：15494–15505.

[27] KUROIWAA，NOMURAY，OCHIAIT，etal. Antibacterial， hydrophilic effect and mechanical properties oforthodonticresincoatedwithUV-responsive photocatalyst[J]. Materials， 2018， 11（6）：889.

[28] SHIBATA T， HAMADA N， KIMOTO K， et al. Antifungal effectofacrylicaparesincontainingtite-coatedTiO2 photocatalyst[J]. DentalMaterialsJournal， 2007， 26（3）：437–444.

[29] AKIBA N， HAYAKAWA I， KEH E S， et al. Antifungal effectsof atissueconditionercoatingagentwithTiO2 photocatalyst[J]. Journal of Medical and Dental Sciences， 2005， 52（4）：223–227.

[30] UCHIMARUM，SAKAIT，MOROIR，etal. Antimicrobial and antifungal effects of tissue conditionerscontainingaphotocatalyst[J]. DentalMaterialsJournal， 2011， 30（5）：691–699.

[31] MINATO K， KATSUTA Y， OTSUKA Y， et al. Effects of toothbrush abrasion on surface and antibacterial properties of hydroxyapatite-tryptophan complex with gray Titania[J].Odontology， 2021， 109（4）：819–827.

[32] SUYAMA Y， OTSUKI M， OGISU.S，etal Effects of light sourcesandvisiblelight-activatedtitaniumdioxidephotocatalystonbleaching[J]. DentalMaterialsJournal， 2009， 28（6）：693–699.

[33] KISHI A， OTSUKI M， SADR A， .Effectetal of light units ontoothbleachingwithvisible-lightactivatingtitanium dioxide photocatalyst[J]. DentalMaterialsJournal， 2011，30（5）：723–729.

[34] TANO E， OTSUKI M， KATO J， et al. Effects of 405 nm diodelaserontitaniumoxidebleachingactivation[J]. Photomedicine and Laser Surgery， 2012， 30（11）：648–654.

[35] IQBAL A， SAIDU U， ADAM F， et al. Floating ZnO QDs- modifiedTiO2/LLDPEhybridpolymerfilmforthe effective photodegradation of tetracycline under fluorescent lightirradiation： synthesisandcharacterisation[J].Molecules， 2021， 26（9）：2509.

[36] LI Q， LIU J B， XU Y Y， et al. Fast cross-linked hydrogel as a green light-activated photocatalyst for localized biofilm disruption and brush-free tooth whitening[J]. ACS Applied Materials & Interfaces， 2022， 14（25）：28427–28438.

[37] ROCCUZZO M， LAYTON D M， Roccuzzo A， et al. Clinical outcomes of peri-implantitis treatment and supportive care： a systematic r.eview[J] Clinical OralImplants Research， 2018， 29 Suppl 16：331–350.

[38] RENVERT S， POLYZOIS I. Treatment of pathologic peri- implant pockets[J]. Periodontology， 2000， 2018，76（1）：180–190.

[39] KLINGE B， HULTIN M， BERGLUNDH T. Peri- implantitis[J]. Dental Clinics of North America， 2005， 49（3）：661–676.

[40] MONJEA，ARANDAL，DIAZKT，etal. Impact of maintenance therapy for the prevention of peri-implant diseases： a systematic review and meta-analysis[J]. Journal of Dental Research， 2016， 95（4）：372–379.

[41] LEE C T， HUANG Y W， ZHU L， et al. Prevalencesofperi-implantitis and peri-implant mucositis： systematicreview and meta-analysis[J]. Journal of Dentistry， 2017，62：1–12.

[42] LINDHE J， MEYLE J， Group D of the European Workshop on Periodontology. Peri-implant diseases： consensus report of the Sixth European Workshop on Periodontology[J]. Journal of Clinical Periodontology， 2008， 35（8 Suppl）：282–285.

[43] KAROUSSIS I K， KOTSOVILIS S， FOURMOUSIS I. A comprehensive and critical review of dental implant prognosis in periodontally compromised partially edentulous patients[J]. Clinical Oral Implants Research， 2007， 18（6）：669–679.

[44] PAVICIC D K， KOLCEG M， LAJNERT V， et al. Changes in quality of life induced by tooth whitening are moderated by perfectionism： a randomized， double-blind， placebo- controlled Trial[J]. The International Journal of Prosthodontics， 2018， 31（4）：394–396.

（編輯：董偉）