Cerium Oxide Nanoparticle Loaded with Toluidine Blue as Cavity Disinfectant Activated via Light-Emitting Diode on the Shear Bond Strength and Resin Tag Length of Universal Adhesive: A Scanning Electron Microscope-EDX Study
Restricted accessResearch articleFirst published online March, 2026
Cerium Oxide Nanoparticle Loaded with Toluidine Blue as Cavity Disinfectant Activated via Light-Emitting Diode on the Shear Bond Strength and Resin Tag Length of Universal Adhesive: A Scanning Electron Microscope-EDX Study
Chlorhexidine digluconate (CHX), toluidine blue (TB) photosensitizer (PS), and cerium oxide nanoparticles (CeO2NPs) loaded with TBPS (TB-CeO2NPs) activated via light-emitting diode (LED) on the shear bond strength (SBS) and resin tag length (RTL) of universal adhesive (UA) bonded using self-etch (SE) and etch-and-rinse (ER) approaches to the carious affected dentin (CAD).
Methodology:
A total of 66 mandibular molars were collected, and CAD was identified after the International Caries Detection and Assessment System (ICDAS) criterion 4 or 5. Subsequently, the specimens were allocated into three cohorts based on CAD disinfection protocol (n = 22): Group 1: CHX, Group 2: TBPS, and Group 3: TB-CeO2NPs. Each group was further distributed into two subgroups based on the mode of application of UA, used (n = 11) in each: ER technique (A) and SE technique (B). Composite restorations were built, and all teeth were subjected to artificial aging. One pair of teeth from each cohort underwent RTL assessment via scanning electron microscope. Nine samples were used for SBS and fracture pattern examination via a universal testing machine and a stereomicroscope. One-way ANOVA and post hoc Tukey test were used to compare the means among the different investigated groups (p < 0.05).
Results:
The longest RTL (97.59 ± 1.96 μm) and highest bond strength (11.79 ± 0.83 MPa) were observed in Group 3B (TB-CeO2NPs-SE-UA) samples. Whereas the shortest resin tags (59.70 ± 1.01 μm) and lowest bond integrity (8.56 ± 0.45 MPa) were identified in Group 2A (TBPS-ER-UA).
Conclusion:
TB-CeO2NPs activated via LED can be used as a suitable alternative for CAD disinfection. UA bonded using ER and SE techniques displayed no significant difference in the RTL and bond strength outcomes.
AlSheikhR, AbduldaiemOY, AlkhalifaMS, et al.Different cavity disinfectant efficacy against S.mutans and shear bond strength of caries affected dentin bonded to resin restoration. Photodiagnosis Photodyn Ther, 2023; 42:103560; doi: 10.1016/j.pdpdt.2023.103560
2.
KumariU, ZafarT, ShafqatS, et al.Caries-affected dentin disinfection using Triphala, Indocyanine green, and Potassium Titanyl Phosphate laser and their effect on adhesive bond strength. Photodiagnosis Photodyn Ther, 2023; 41:103257; doi: 10.1016/j.pdpdt.2022.103257
3.
ShadyH, ElsayedH, SalamaM. Shear bond strength of resin composite to remineralized caries affected dentin using chicken eggshell powder. Tanta Dent J, 2022; 19(4):187–196; doi: 10.4103/tdj.tdj_31_22
4.
ShiJH, LiH, WangYN. In vitro remineralization effect of grape seed extract on artificial dentin caries. Shanghai Kou Qiang Yi Xue, 2015; 24(1):18–22.
5.
Poppolo DeusF, OuanounouA. Chlorhexidine in dentistry: Pharmacology, uses, and adverse effects. Int Dent J, 2022; 72(3):269–277; doi: 10.1016/j.identj.2022.01.005
6.
RayarS, SadasivaK, SinghP, et al.Effect of 2% chlorhexidine on resin bond strength and mode of failure using two different adhesives on dentin: An in vitro study. J Pharm Bioallied Sci, 2019; 11(Suppl 2):S325–S330; doi: 10.4103/JPBS.JPBS_23_19
7.
PolettoD, PolettoAC, CavalaroA, et al.Smear layer removal by different chemical solutions used with or without ultrasonic activation after post preparation. Restor Dent Endod, 2017; 42(4):324–331; doi: 10.5395/rde.2017.42.4.324
8.
Al DeebL, Bin-ShuwaishMS, AbrarE, et al.Efficacy of chlorhexidine, Er Cr YSGG laser and photodynamic therapy on the adhesive bond integrity of caries affected dentin. An in-vitro study. Photodiagnosis Photodyn Ther, 2020; 31:101875; doi: 10.1016/j.pdpdt.2020.101875
9.
AlanaziAM, KhanNA, KhanAA, et al.Titanium oxide and chitosan nanoparticles loaded in methylene blue activated by photodynamic therapy on caries affected dentin disinfection, bond strength, and smear layer removal efficacy. Photodiagnosis Photodyn Ther, 2024; 50:104343; doi: 10.1016/j.pdpdt.2024.104343
10.
Al-KheraifAA, MohamedBA, SufyanAOH, et al.Photodynamic therapy and other pretreatment methods on epoxy-based glass fiber post on the push-out bond strength to radicular dentin. Photodiagnosis Photodyn Ther, 2021; 36:102526; doi: 10.1016/j.pdpdt.2021.102526
11.
GökT, Er KaraogluG, KorucuH. Effect of phthalocyanine, methylene blue and toluidine blue photosensitizers on the adhesive interface of fiber posts: A confocal laser microscopy study. Lasers Med Sci, 2025; 40(1):106–109; doi: 10.1007/s10103-025-04369-z
12.
SantanaAP, CunhaDM, PiazzaRD, et al.Butyl toluidine blue as a photosensitizer for antimicrobial photodynamic therapy on titanium-associated biofilms. J Photochem Photobiol B, 2025; 273:113274; doi: 10.1016/j.jphotobiol.2025.113274
13.
JandtKD, WattsDC. Nanotechnology in dentistry: Present and future perspectives on dental nanomaterials. Dent Mater, 2020; 36(11):1365–1378; doi: 10.1016/j.dental.2020.08.006
14.
PourhajibagherM, BahadorA. Physico-Mechanical properties, antimicrobial activities, and anti-biofilm potencies of orthodontic adhesive containing cerium oxide nanoparticles against Streptococcus mutans. Folia Med (Plovdiv), 2022; 64(2):252–259; doi: 10.3897/folmed.64.e60418
15.
AlotaibiB, GaafarSS, AljuailanR, et al.Photochemically activated microbubble emulsion, Nd: Yap laser, and cerium oxide nanoparticles as canal disinfectants on push-out bond strength of sealer to root dentin, smear layer, and antibacterial efficacy. Microsc Res Tech, 2025; 88(6):1654–1663; doi: 10.1002/jemt.24802
16.
TuncerNC, BarutcugilC. One-year evaluation of microtensile bond strength of universal adhesives in Self-etch or Etch and Rinse modes to dentin groups at different caries-affected degree. Int J Adhes Adhes, 2025; 138:103919; doi: 10.1016/j.ijadhadh.2024.103919
17.
BreschiL, MaravicT, MazzitelliC, et al.The evolution of adhesive dentistry: From etch-and-rinse to universal bonding systems. Dent Mater, 2025; 41(2):141–158; doi: 10.1016/j.dental.2024.11.011
18.
ChenH, FengS, JinY, et al.Comparison of bond strength of universal adhesives using different etching modes: A systematic review and meta-analysis. Dent Mater J, 2022; 41(1):1–10; doi: 10.4012/DMJ.2021-111
19.
KuriharaC, Kerpel-FroniusS, BeckerS, et al.Declaration of Helsinki: Ethical norm in pursuit of common global goals. Front Med (Lausanne), 2024; 11:1360653; doi: 10.3389/fmed.2024.1360653
20.
Al-KhureifAA, MohamedBA, KhanAA. Resin modified glass ionomer bonded to caries affected dentin disinfected with carbon dioxide laser, diode lasers, bee glue and photosensitizing agents: An estimation of bond strength. Photodiagnosis Photodyn Ther, 2022; 38:102829; doi: 10.1016/j.pdpdt.2022.102829
21.
WilliamsJA, PearsonGJ, CollesMJ, et al.The photo-activated antibacterial action of toluidine blue O in a collagen matrix and in carious dentine. Caries Res, 2004; 38(6):530–536; doi: 10.1159/000080582
22.
AlrefeaiMH, AljamhanAS, AlhabdanA, et al.Influence of methylene blue, Riboflavin, and indocyanine green on the bond strength of caries affected dentin when bonded to resin-modified glass ionomer cement. Photodiagnosis Photodyn Ther, 2022; 38:102792; doi: 10.1016/j.pdpdt.2022.102792
23.
AljamhanAS, AlrefeaiMH, AlhabdanA, et al.Influence of ER-CR-YSGG laser and photodynamic therapy on the dentin bond integrity of nano-hydroxyapatite containing resin dentin adhesive: SEM-EDX. mdpi.com. Polymers (Basel), 2021; 13(12):1903; doi: 10.3390/polym13121903
24.
FerrariM, GrandiniS, SimonettiM, et al.Influence of a microbrush on bonding fiber post into root canals under clinical conditions. Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 2002; 94(5):627–631; doi: 10.1067/moe.2002.129184
25.
AlrahlahA, NaseemM, TanveerSA, et al.Influence of disinfection of caries effected dentin with different concentration of silver diamine fluoride, curcumin and Er, Cr:YSGG on adhesive bond strength to resin composite. Photodiagnosis Photodyn Ther, 2020; 32:102065; doi: 10.1016/j.pdpdt.2020.102065
26.
SundfeldRH, ValentinoTA, Sversut De AlexandreR, et al.Hybrid layer thickness and resin tag length of a self-etching adhesive bonded to sound dentin. J Dent, 2005; 33(8):675–681; doi: 10.1016/j.jdent.2005.01.011
27.
AlQhtaniFABA, AlkahtaniZM, SainudeenS, et al.To evaluate μTBS, Microleakage, and resin tag length via scanning electron microscopy of different resin Sealants Clinpro and Embrace bonded to the intact enamel in primary molars. Microsc Res Tech, 2025; 88(9):2504–2511; doi: 10.1002/JEMT.24876
28.
SuryaraoPS, GaonkarN, ShashikiranN, et al.Comparative evaluation of microshear bond strength of adhesive resin incorporated with inorganic nanofillers cerium dioxide: An in-vitro study. Jcdr, 2022; doi: 10.7860/jcdr/2022/57950.17096
29.
GarciaIM, LeituneVCB, TakimiAS, et al.Cerium dioxide particles to tune radiopacity of dental adhesives: Microstructural and physico-chemical evaluation. J Funct Biomater, 2020; 11(1):7; doi: 10.3390/jfb11010007
30.
WangY, ZhangX, ZhengH, et al.Remineralization of dentin with cerium oxide and its potential use for root canal disinfection. Int J Nanomedicine, 2024; 19:1–17; doi: 10.2147/IJN.S441060
31.
KalaycıoğluZ, Özuğur UysalB, PekcanÖ, et al.Efficient photocatalytic degradation of methylene blue dye from aqueous solution with cerium oxide nanoparticles and graphene oxide-doped polyacrylamide. ACS Omega, 2023; 8(14):13004–13015; doi: 10.1021/acsomega.3c00198
32.
LapinskaB, KlimekL, SokolowskiJ, et al.Dentine surface morphology after chlorhexidine application-SEM study. Polymers (Basel), 2018; 10(8):905; doi: 10.3390/polym10080905
33.
CamposEA, CorrerGM, LeonardiDP, et al.Chlorhexidine diminishes the loss of bond strength over time under simulated pulpal pressure and thermo-mechanical stressing. J Dent, 2009; 37(2):108–114; doi: 10.1016/j.jdent.2008.10.003
34.
ShafieiF, AlikhaniA, AlaviAA. Effect of chlorhexidine on bonding durability of two self-etching adhesives with and without antibacterial agent to dentin. Dent Res J (Isfahan), 2013; 10(6):795–801.
35.
AlshahraniA, AbrarE, MaawadhAM, et al.Management of caries affected dentin (CAD) with resin modified glass ionomer cement (RMGIC) in the presence of different caries disinfectants and photosensitizers. Photodiagnosis Photodyn Ther, 2020; 32:101978; doi: 10.1016/j.pdpdt.2020.101978
36.
FuC, DengS, KoneskiI, et al.Multiscale in-vitro analysis of photo-activated riboflavin incorporated in an experimental universal adhesive. J Mech Behav Biomed Mater, 2020; 112:104082; doi: 10.1016/j.jmbbm.2020.104082
37.
NicolosoGF, AntoniazziBF, LenziTL, et al.The bonding performance of a universal adhesive to artificially-created caries-affected dentin. J Adhes Dent, 2017; 19(4):317–321; doi: 10.3290/j.jad.a38890
38.
ArifaMK, EphraimR, RajamaniT. Recent advances in dental hard tissue remineralization: A review of literature. Int J Clin Pediatr Dent, 2019; 12(2):139–144; doi: 10.5005/jp-journals-10005-1603
39.
DevadigaD, ShettyP, HegdeMN, et al.Bioactive remineralization of dentin surface with calcium phosphate-based agents: An in vitro analysis. J Conserv Dent, 2022; 25(1):93–97; doi: 10.4103/jcd.jcd_583_21
40.
AlsunbulH, AlmutairiB, AljanakhM, et al.Hybrid ceramic repair strength, surface roughness, and bond failure, using methylene blue-activated low-level laser therapy, Carbon dioxide, and Ti: Al2O3 laser. Photodiagnosis Photodyn Ther, 2023; 43:103693; doi: 10.1016/j.pdpdt.2023.103693
