This study was performed to determine the bactericidal effects of erbium:yttrium–aluminum–garnet (Er:YAG) laser irradiation and the morphological and chemical composition changes in bovine dentin.
Methods:
Dentin slabs were prepared from bovine incisors, and then cultured with Streptococcus mutans to produce bacteria-infected dentin samples. The samples were randomly divided into five groups with Er:YAG laser irradiation energy densities of 0, 6.37, 12.73, 19.11, and 25.47 J/cm2. After irradiation, samples were stained and observed by confocal laser scanning microscopy. The bactericidal abilities were measured using live/dead staining. The morphology and chemical components were investigated by scanning electron microscopy and energy-dispersive spectrometry.
Results:
After irradiation, the elimination of bacteria and the smear layer were significantly better in the high energy density groups (19.11, 25.47 J/cm2) than in the low energy density groups (6.37, 12.73 J/cm2; p < 0.001). On morphological examination, the group with minimum energy density (6.37 J/cm2) showed superficial melting. In the high energy density groups (12.73, 19.11, and 25.47 J/cm2), laser-irradiated dentin showed a clean surface with open orifices. Significant increases were observed in the weight percentages of calcium (from 19.75 ± 0.69 to 34.47 ± 2.91, p < 0.001) and phosphate (from 8.58 ± 0.43 to 15.10 ± 1.81, p < 0.001), whereas significant decreases were observed for oxygen (from 49.84 ± 0.69 to 36.39 ± 2.86, p < 0.001) and carbon (from 26.06 ± 3.58 to 12.80 ± 2.26, p < 0.01) with increasing energy density.
Conclusions:
This study confirmed that Er:YAG laser irradiation has bactericidal and dentin conditioning effects.
Get full access to this article
View all access options for this article.
References
1.
AasJA, GriffenAL, DardisSR, et al.Bacteria of dental caries in primary and permanent teeth in children and young adults. J Clin Microbiol, 2008; 46:1407–1417.
2.
BaiJ. The results of the Fourth National Epidemiological Survey of Oral Health in China [EB/OL]. 2017. Available at: http://www.gov.cn/xinwen/2017-09/20/content_5226224.htm
3.
PetersenPE. World health organization global policy for improvement of oral health—world health assembly 2007. Int Dent J, 2011; 58:115–121.
4.
BurrowM, RickettsD, KiddE, InnesN, ClarksonJ.Complete or ultraconservative removal of decayed tissue in unfilled teeth. Cochrane Database Syst Rev, 2009; 54:274–276.
5.
DeANA, CoutinhoE, CardosoMV, LambrechtsP, VanMB. Current concepts and techniques for caries excavation and adhesion to residual dentin. J Adhes Dent, 2011; 13:7.
6.
FriedD, FeatherstoneJDB, VisuriSR, SekaWD. Caries inhibition potential of Er:YAG and Er:YSGG laser radiation. Proc SPIE Int Soc Opt Eng, 1996; 2672:73–78.
7.
RamazaniN, AhmadiR, DaryaeianM.Oral and dental laser treatments for children: applications, advantages and considerations. J Lasers Med Sci, 2012; 3:44–49.
8.
SarmadiR, HedmanE, GabreP.Laser in caries treatment—patients' experiences and opinions. Int J Dent Hyg, 2014; 12:67–73.
9.
HibstR, KellerU.Experimental studies of the application of the Er:YAG laser on dental hard substances: I. measurement of the ablation rate. Lasers Surg Med, 2010; 9:338–344.
10.
CarusoS, BernardiS, PasiniM, et al.The process of mineralisation in the development of human tooth. Eur J Paediatr Dent, 2016; 17:322–326.
NyvadB, CrielaardW, MiraA, TakahashiN, BeightonD.Dental caries from a molecular microbiological perspective. Caries Res, 2013; 47:89–102.
13.
TakahashiN, NyvadB.The role of bacteria in the caries process: ecological perspectives. J Dent Res, 2011; 90:294–303.
14.
BorsattoMC, TorresCP, ChinelattiMA, PécoraJD, CoronaSA, Palma-DibbRG. Effect of Er:YAG laser parameters on ablation capacity and morphology of primary enamel. Photomed Laser Surg, 2009; 27:253–260.
15.
GaliaZ, MayaR, Jean-PaulR.Minimally invasive treatment of dental caries in primary teeth using an Er:YAG laser. Laser Ther, 2014; 23:249–254.
16.
SchoopU, KlugerW, MoritzA, NedjelikN, GeorgopoulosA, SperrW. Bactericidal effect of different laser systems in the deep layers of dentin. Lasers Surg Med 2004;35:111–116.
17.
LeeBS, LinYW, ChiaJS, et al.Bactericidal effects of diode laser on Streptococcus mutans after irradiation through different thickness of dentin. Lasers Surg Med, 2010; 38:62–69.
18.
ArnabatJ, EscribanoC, FenosaA, et al.Bactericidal activity of erbium, chromium:yttrium-scandium-gallium-garnet laser in root canals. Lasers Med Sci, 2010; 25:805–810.
19.
WangQ, ZhangCX. Evaluation of the bactericidal effect of Er,Cr:YSGG, and Nd:YAG lasers in experimentally infected root canals. J Endod, 2007; 33:830–832.
20.
GuidottiR, MerigoE, FornainiC, RoccaJP, MedioniE, VescoviP.Er:YAG 2,940-nm laser fiber in endodontic treatment: a help in removing smear layer. Lasers Med Sci, 2014; 29:69–75.
PerinFM, FrançaSC, Silva-SousaYTC, AlfredoE, SaquyPC, EstrelaC, Sousa-NetoMD. Evaluation of the antimicrobial effect of Er:YAG laser irradiation versus 1% sodium hypochlorite irrigation for root canal disinfection. Aust Endod J, 2010; 30:20–22.
23.
ManeshSK, DarlingCL, FriedD.Imaging natural and artificial demineralization on dentin surfaces with polarization sensitive optical coherence tomography. Proc SPIE Int Soc Opt Eng, 2008; 6843:1004–1020.
24.
De AndradeLEH, PelinoJEP, LizarelliRFZ, BagnatoVS, De OliveiraOB. Caries resistance of lased human enamel with Er:YAG laser—morphological and ratio Ca/P analysis. Laser Phys Lett, 2010; 4:157–162.
25.
AltinokB, TanbogaI, PekerS, ErenF, BakkalM, PekerF.The effect of laser-activated acidulated phosphate fluoride on enamel submitted to erosive solution only: an in vitro preliminary evaluation. Eur J Paediatr Dent, 2011; 12:13–19.
26.
ChowLC. Next generation calcium phosphate-based biomaterials. Dent Mater J, 2009; 28:1–10.
27.
RamalhoKM, HsuCY, de FreitasPM, et al.Erbium lasers for the prevention of enamel and dentin demineralization: a literature review. Photomed Laser Surg, 2015; 33:301–319.
28.
KukidomeN, AmagaiT., OsukaK., et al.Bactericidal effects of 2.94 μm and 1.67 μm laser. Bull Tokyo Dent Coll, 2010; 51:185–192.
29.
ParkSN, LimYK, ChoiMH, et al.Antimicrobial mechanism of oleanolic and ursolic acids on Streptococcus mutans ua159. Curr Microbiol, 2017; 75:1–9.
30.
D'Ercole SimonettaDT, GiuseppeM, SaraB, et al.Microleakage of bacteria in different implant-abutment assemblies: an in vitro study. J Appl Biomater Funct Mater, 2015; 13:e174–e180.
31.
SaharhelftS, StabholtzA, MoshonovJ, GutkinV, RedenskiI, SteinbergD. Effect of Er:YAG laser-activated irrigation solution on Enterococcus faecalis biofilm in an ex-vivo root canal model. Photomed Laser Surg, 2013; 31:334.
32.
AsnaashariM, SafaviN.Disinfection of contaminated canals by different laser wavelengths, while performing root canal therapy. J Lasers Med Sci, 2013; 4:8–16.
33.
MeloMAS, De-PaulaDM, LimaJPM, et al.In vitro photodynamic antimicrobial chemotherapy in dentine contaminated by cariogenic bacteria. Laser Phys Lett, 2010; 20:1504–1513.
34.
Dos Santos AntonioMP, Moura-NettoC, CamargoSE, DavidowiczH, MarquesMM, Maranhão de MouraAA. Bactericidal effects of two parameters of Er:YAG laser intracanal irradiation: ex-vivo study. Lasers Med Sci, 2012; 27:1165–1168.
35.
FeatherstoneJD. Caries detection and prevention with laser energy. Dent Clin North Am, 2000; 44:955–969.
36.
MoosaviH, GhorbanzadehS, AhrariF.Structural and morphological changes in human dentin after ablative and subablative Er:YAG laser irradiation. J Lasers Med Sci, 2016; 7:86–91.
37.
CelikEU, ErgücüZ, TürkünLS, TürkünM.Effect of different laser devices on the composition and microhardness of dentin. Oper Dent, 2008; 33:496–501.
38.
HossainM, NakamuraY, TamakiY, YamadaY, MurakamiY, MatsumotoK.Atomic analysis and knoop hardness measurement of the cavity floor prepared by Er,Cr:YSGG laser irradiation in vitro. J Oral Rehabil, 2010; 30:515–521.
39.
MeiML, ItoL, ChuCH, LoEC, ZhangCF. Prevention of dentine caries using silver diamine fluoride application followed by Er:YAG laser irradiation: an in vitro study. Lasers Med Sci, 2014; 29:1785–1791.
40.
ManeshSK, DarlingCL, FriedD.Imaging natural and artificial demineralization on dentin surfaces with polarization sensitive optical coherence tomography. Proc SPIE Int Soc Opt Eng, 2008; 6843:1004–1020.
41.
ManeshSK, DarlingCL, FriedD.Nondestructive assessment of dentin demineralization using polarization-sensitive optical coherence tomography after exposure to fluoride and laser irradiation. J Biomed Mater Res B Appl Biomater, 2009;90B:802–812.
42.
CeballosL, ToledanoM, OsorioR, GarcíagodoyF, FlaitzC, HicksJ.Er-YAG laser pretreatment effect on in vitro secondary caries formation around composite restorations. Am J Dent, 2001; 14:46–49.
43.
ChalmersNI, OhK, HughesCV, et al.Pulp and plaque microbiotas of children with severe early childhood caries. J Oral Microbiol, 2015; 7:25951.
44.
Simón-SoroA, Guillen-NavarroM, MiraA. Metatranscriptomics reveals overall active bacterial composition in caries lesions. J Oral Microbiol, 2014; 6:25443.
