The Journal of Contemporary Dental Practice
Volume 21 | Issue 4 | Year 2020

Dentin Conditioning Using Different Laser Prototypes (Er,Cr:YSGG; Er:YAG) on Bond Assessment of Resin-modified Glass Ionomer Cement

Fahad Alkhudhairy

Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Riyadh, Kingdom of Saudi Arabia

Corresponding Author: Fahad Alkhudhairy, Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Riyadh, Kingdom of Saudi Arabia, Phone: +966 559917888, e-mail: falkhudhairy@ksu.edu.sa

How to cite this article Alkhudhairy F. Dentin Conditioning Using Different Laser Prototypes (Er,Cr:YSGG; Er:YAG) on Bond Assessment of Resin-modified Glass Ionomer Cement. J Contemp Dent Pract 2020;21(4):426–430.

Source of support: The author extends his appreciation to the Deanship of Scientific Research at King Saud University for funding this work through research group no. (RGP-1438-028)

Conflict of interest: None


Aim: The aim of this study was to evaluate and compare various conditioning regimes (laser and conventional) on shear bond strength (SBS) of resin-modified glass ionomer cement (RMGIC) bonded to dentin.

Materials and methods: Sixty non-carious intact maxillary molars were cleaned, isolated, and randomly divided into six groups (n = 10). Before randomization, the dentin surface was exposed and finished. Samples in group I were conditioned using Er,Cr:YSGG laser (ECYL). Specimens in group II were conditioned using Er:YAG laser (EYL), and the dentin surfaces of specimens in group III and group IV were conditioned using cavity conditioner and K930. Similarly, the samples in group V and group VI were surface treated using 17% EDTA and total etch. All samples were bonded with RMGIC following conditioning regime. For SBS testing, the samples were placed in universal testing machine. A fracture analysis of debonded surfaces was evaluated using stereomicroscope at 40× magnification. Means and standard deviations (SDs) were calculated using analysis of variance (ANOVA) and Tukey’s post hoc test at a significant level of p %3C; 0.05.

Results: The maximum bond strength values were observed in group VI total etch (23.85 ± 3.67). The lowest bond strength was displayed in laser dentin group II conditioned by EYL (11.65 ± 2.77). Dentin conditioned with ECYL, cavity conditioner, K930 conditioner, and 17% ethylenediaminetetraacetic acid (EDTA) were found to be comparable, p %3E; 0.05. Cohesive failure was dominant among experimental groups.

Conclusion: Er,Cr:YSGG laser has a potential to be recommended for dentin conditioning prior to application of RMGIC.

Clinical significance: Dentin conditioning enhances adhesion of RMGIC for improved prognosis and treatment outcome.

Keywords: Bond integrity, Er,Cr:YSGG, Er:Yag, Resin-modified glass ionomer cement, Surface conditioning.


Premature restorative failure is a foremost concern in clinical dentistry. The failure is a reason of weak bond between the substrate and restorative interface resulting in poor prognosis and treatment outcome.1 The goal to find an ideal restorative material led to the evolution of resin-modified glass ionomer cement (RMGIC). A typical RMGIC consists of 80% fluoro-aluminium silicate in the form of glass ionomer cement (GIC) with polyacrylic acid (PAA) and 20% light-polymerized resin hydroxy-ethylmethacrylate (HEMA) or bisphenol A-glycidyl methacrylate (Bis-GMA) in the form of methacrylate.2

Resin-modified glass ionomer cements are hybrid materials and have characteristics better than conventional GIC. The properties of RMGIC range from better esthetics, improved handling, increased working time, and higher moisture resistance.3 However, a controversy exists in the literature regarding the adhesion of GICs to dentin. Some studies suggest that RMGIC adheres to the tooth physiochemically without the need of conditioning,4,5 whereas other studies have stated that conditioning of dentin is necessary to improve bond strength values.2,6

Dentin conditioners in the form of PAA, cavity conditioners, phosphoric acid, and EDTA have been documented to improve bond durability and strength when applied prior to RMGIC.6,7 The use of conditioners removes smear layer, demineralizes, and makes dentin surface more receptive for bonding.8 Moreover, conditioning favors bonding of RMGIC with dentin both mechanically and chemically.4

Alternatively, the use of ECYL and EYL for enamel/dentin and dental ceramics conditioning has exhibited convincing and favorable results.912 Er,Cr:YSGG laser working at the wavelength of 2,780 nm open dental tubules removes smear layer resulting in micro-retentive dentinal pattern.13,14 Moreover, EYL ablates dentin structure without thermal damage at 2,940 nm wavelength which facilitates adhesion of restorative material.15,16

To our knowledge from indexed literature, scarce evidence exists on the use of ECYL and EYL as dentin conditioner bonded with RMGIC. Moreover, limited data on comparison of conventional conditioning regimes with ECYL and EYL have been documented. It is hypothesized that dentin conditioned with cavity conditioner (control) prior to RMGIC will exhibit bond strength values comparable with ECYL and EYL. Therefore, the aim of this study was to evaluate and compare various conditioning regimes (laser and conventional) on SBS of RMGIC bonded to dentin.


Sixty non-carious, unrestored, intact maxillary third molars were collected in a period of 1 year as a bonding substrate and were stored in 0.4% sodium azide solution (NaN3) (Merck, Germany). The specimens were cleaned with periodontal scaler and curette (Perio Soft-Scaler; Kerr Dental, Denmark) to remove debris and inorganic remnants and stored in chloramine T trihydrate solution (Merck) for 1 week following storage in distilled water at 4°C until use.

The samples were embedded vertically in self-cure acrylic resin (Opti-cryl, South Carolina, Columbia) up to cement-o-enamel junction within polyvinyl pipes of 4 mm diameter. Model trimmer (IsoMet; Buehler, USA) under irrigation was used to wet ground the occlusal surface, to expose dentinal surface finished with silicon carbide grinding disks 1,200 grits (Buehler, Great Britain, UK). Based on the conditioning regimes, the samples were randomly classified into six groups (n = 10 each)

Group I: The samples were conditioned with ECYL (Waterlase; Biolase Technology, San Clemente, CA) at 0.5 W and 30 Hz frequency from 2 mm distance in a noncontact position for a duration of 60 seconds using a laser tip MZ8. The air/water pressure was 65%/55%.

Group II: The surface of bonded specimen was treated using EYL (Kavo Key Laser 2; Kavo Corp., Biberach, Germany). The laser was used in a circular motion at 350 mJ of energy and 2 Hz of pulse repetition for a duration of 60 seconds at 2 mm distance.

Group III: The surface of the samples was conditioned using a cavity conditioner (GC America, Inc, Latin America) applied for a duration of 10 seconds and washed and air-dried without desiccation.

Group IV: Bonded dentinal surface of specimens was conditioned using K930 conditioner (GC America, Inc, Latin America) for 15 seconds and washed and air-dried for 3 seconds without desiccation.

Group V: Dentinal surface of the specimens was surface treated with 17% EDTA (Pyrex Pharmaceutical, USA) for 30 seconds and washed for 15 seconds and blow-dried without desiccation.

Group VI: All samples in this group were exposed with 37% phosphoric acid (Aqua Etch, India) for 10 seconds and rinsed thoroughly for 10 seconds. Bonding agent (Prime and Bond NT; Dentsply, Sirona, USA) was applied for 10 seconds and air-dried and light cured (Bluephase G2; Ivoclar Vivadent, Schaan, Liechtenstein) 10 seconds.

All samples were now bonded with RMGIC Fuji II LC (GC Corporation, Tokyo Japan) and mixed and applied incrementally (2-mm-thick increment) in accordance with the manufacturer’s instructions and light cured for 20 seconds (Bluephase G2; Ivoclar Vivadent). A protective varnish was applied, and the specimens were stored in distilled water for 24 hours followed by SBS testing (Table 1).

SBS Testing of Specimens

Specimens were placed at the lower base of universal testing machine (Lloyds LF-Plus; Ametek, Inc., Great Britain, UK) so that the bonded base cylinder was parallel to the direction of force at 0.5 mm/minute crosshead speed until fracture. The load required to debond was recorded in Newton but calculated in megapascals.

Table 1: Materials used in this study
Fuji II LCGC Corporation, Tokyo JapanFluoro-aluminium silicate glass, polyacrylic acid, HEMA
Cavity conditionerGC America, Inc.20% polyacrylic acid, AlCl3
K930 conditionerGC America, Inc.12% citric acid, 4% AlCl3
17% EDTAPyrex Pharmaceutical17% poly-amino carboxylic acid
Optibond Solo Plus (total etch)KaVo Kerr, West Collins, Orange, CABisphenol glycidyl methacrylate, glycerol DMA, glycerol phosphate DMA, DMAs, ethanol silicone oxide, barium borosilicate, and sodium hexafluoro-silicate

DMA, dimethylarsenate

Fracture Analysis

Fracture surfaces of debonded specimens were analyzed under stereomicroscope (SR; Zeiss, Oberkochen, Germany) at 40× magnification by a single examiner to minimize bias. The modes of failure of samples were classified into adhesive (substrate–adhesive interface), cohesive (in the materials or in substrate itself), and admixed (involving both interfaces of material and substrate). Failure sites were not statistically examined.

Statistical Assessment

Normality of the data were assessed using Kolmogorov–Smirnov test, and equality of variance assumptions was evaluated by modified Levene test. Means and standard deviations were calculated using ANOVA and Tukey’s post hoc test at a significant level of p %3C; 0.05.


Normal distribution of data was observed in this study. For bond strength values, ANOVA showed a significant difference among all the experimental groups (p < 0.05). The maximum bond strength values were observed in group VI total etch (23.85 ± 3.67). The lowest bond strength was displayed in laser dentin group II conditioned by EYL (11.65 ± 2.77). Dentin conditioned with ECYL in group I, cavity conditioner in group III, K930 conditioner in group IV, and 17% EDTA in group V was found to be comparable, p %3E; 0.05 (Table 2 and Fig. 1).

Fracture analysis of debonded specimen revealed cohesive failure among group I, group III, group IV, group V, and group VI. Moreover, the adhesive failure type was observed in group II conditioned with EYL (Table 3 and Fig. 2).


The present laboratory-based study was constructed on the hypothesis that conventional conditioning of dentin using cavity conditioner will exhibit bond integrity similar to laser dentin (ECYL and EYL). Interestingly, the present in vitro study revealed that conditioning of dentin with ECYL exhibited comparable SBS with dentin conditioned with 17% EDTA, cavity conditioner, and K930 conditioner. While dentin conditioned with EYL displayed low bond integrity with RMGIC. Therefore, the hypothesis of this study was partially accepted. In this study, the SBS values were assessed using a universal testing machine as the method is homogeneous, easy to use, and displays quantitative data for comparative analysis. Furthermore, the test is beneficial for depth profiling and screening of RMGIC and GIC.17,18

Table 2: Using analysis of variance (ANOVA) and Tukey’s multiple comparison test for the comparison of means and SD for bond strength values among study groups
Material typeType of conditioningMean ± SDp value*
Fuji II LC (RMGIC)Group I: Er,Cr:YSGG laser (ECYL)18.25 ± 3.22a< 0.05
Group II: Er:YAG laser (EYL)11.65 ± 2.77b
Group III: cavity conditioner (control)17.54 ± 2.93a
Group IV: K930 conditioner18.33 ± 2.52a
Group V: 17% ethylenediaminetetraacetic acid (EDTA)19.25 ± 3.21a
Group VI: total etch23.85 ± 3.67c

Different superscript letters in individual materials indicate statistical differences (p < 0.05); *Showing significant difference among study group (ANOVA)

The bonding of restorative material to dentin structure is complex. Conditioning of dentin preceding RMGIC modifies the dentin by making it receptive to bond, eliminates smear layer, and enhances surface wettability.11 In this study, dentin conditioned with EYL exhibited the lowest bond strength (11.65 ± 2.77) among all investigational groups. Er:YAG laser is well absorbed by the dental tissues and the wavelength on which EYL works coincide with absorption band of water (approximately 3 μm) and hydroxyapatite crystals of dentin.19 Evidence dictates that low bond scores shown by EYL can be attributed to heat production resulting in structural damage to dentin.19,20 Moreover, excessive heat may result in denaturation of the collagen network preventing diffusion of monomer compromising bond integrity.21 It can be also estimated that thermal effect by EYL may compromise interdiffusion zone formation between RMGIC and dentin substrate.20,21 The finding of low bond score by EYL in this study was in harmony with the work by De Souza-Gabriel et al.19 However, studies by Hibst and Keller22 and Visur et al.23 argue that heat produced by EYL does not damage the dentin and propagates into pulp. In contrast, conditioning of dentin with ECYL (18.25 ± 3.22) exhibited bond strength comparable with cavity conditioner (17.54 ± 2.93), K930 (18.33 ± 2.52), and 17% EDTA (19.25 ± 3.21). In this study, ECYL was used at 0.5 W and 30 Hz, and these laser parameters below ablation threshold favor ionic exchange between dentin and RMGIC through the formation of an intermediary layer.14,24 Moreover, these low energy density parameters increase the content of phosphorous, calcium, and magnesium on the tooth surface, thereby improving adhesion.24 However, the work by Jordehi et al.25 advocates that laser irradiation of dentin decreased SBS values in GIC. Although findings of our study was in line with Garbui et al.,24 these heterogeneous outcomes can be attributed to the use of different laser parameters, type of testing (SBS or microtensile bond strength), thick ness of dentin, form of dentin (human or bovine), irradiation time and distance, and type of material.

Fig. 1: Line chart displaying shear bond strength among the investigational groups. Group I, Er,Cr:YSGG laser (ECYL); group II, Er:YAG laser (EYL); group III, cavity conditioner (control); group IV, K930 conditioner; group V, 17% ethylenediaminetetraacetic acid (EDTA); group VI, total etch

Finding of no significant difference was found with cavity conditioners (17.54 ± 2.93), K930 (18.33 ± 2.52), and 17% EDTA (19.25 ± 3.21) with Fuji II LC. It has been demonstrated in previous studies that PAA in the form of cavity conditioner enhanced bond strength by creating irregularities on the substrate surface and AlCl3 in cavity conditioner stabilized dental collagen for easy penetration of HEMA in RMGIC during dentin demineralization.4,26 Moreover, citric acid used as dentin conditioning agent was first used by Hotz et al.27 In this study, 12% citric acid was used in the form of K930 exhibiting better SBS compared with cavity conditioner. Documented evidence suggests that K930 at low pH (0.82) cleans and chelates both the surface and the cement.4 In addition, K930 at decreased pH dissolves the smear layer increasing the molecular interaction between the surface substrate and poly anions in the cement, thereby improving adhesion.28 The finding of this study was in concurrent with the work of Terata et al.29 However, the work by Powis et al.30 contends against the use of K930 as conditioner since its use dissolves the calcium- and phosphate-rich material in dentin and denatures the dentinal collagen. In authors’ opinion, diversity in results can be credited to concentration and duration of citric acid applied, type of material RMGIC/GIC, and nature of dentin superficial or deep.

Dentin conditioned with 17% EDTA displayed mean bond strength value of 19.25 ± 3.21. A possible explanation to this outcome can be ascribed to its less aggressive nature to decalcify dentin creating low and thin resin tags, widening of dental orifice, and formation of thin hybrid layer without dissolving dentinal proteins.31 This analysis is validated by Rai et al.,6 asserting that 17% EDTA used as a conditioner on dentin presented better bond integrity with three different types of RMGIC. The highest bond strength values were noted in the total etch group. This outcome was in concurrent with the work by Poggio32 and Imbery et al.2 Improved removal of smear layer and better opening of dentinal tubules resulting in effective penetration of resin monomer forming a healthier diffusion zone between dentin and cement ensuing both mechanical and chemical interlocking are some factors contributing to highest bond scores in this group.

Table 3: Percentage distribution of modes of failure
Failure type (%)Group I: Er,Cr:YSGG laser (ECYL)Group II: Er:YAG laser (EYL)Group III: cavity conditioner (control)Group IV: K930 conditionerGroup V: 17% EDTAGroup VI: total etch

Fig. 2: Multiple bar chart showing fracture analysis among different groups. Group I, Er,Cr:YSGG laser (ECYL); group II, Er:YAG laser (EYL); group III, cavity conditioner (control); group IV, K930 conditioner; group V, 17% ethylenediaminetetraacetic acid (EDTA); group VI, total etch

Majority of failure type among experimental groups was cohesive. While adhesive failure was noted in the EYL group only. The type of failure in different experimental groups corresponded to SBS scores. Cohesive failure is found to be common in RMGIC due to porosity within the cement itself. It is expected that these porous areas within the material act as stress concentrators from where the fracture is instigated.

Within the limitations of this study, the greatest drawback of the current in vitro study was not performing micromorphological evaluation of the conditioned dentin surface and dispersive spectroscopy of the debonded surface. The concept of conditioning dentin with different laser prototypes is a novel concept and needs further clinical and lab-based evaluation under different laser parameters. Element analysis along with material mapping is proposed for RMGIC on dentin conditioned with ECYL and EYL. Resin-modified glass ionomer cement bonded on laser dentin under short- and long-simulated aging needs to be investigated. Scope on the use of ECYL for surface conditioning is huge as it offers comfort of application intra-orally, patient and dentists ease, and nominal contamination. Therefore, further researches for progress of this technique are suggested.


ECYL has a potential to be recommended for dentin conditioning prior to application of RMGIC.


1. Altunsoy M, Botsali MS, Korkut E, et al. Effect of different surface treatments on the shear and microtensile bond strength of resin-modified glass ionomer cement to dentin. Acta Odontol Scand 2014;72(8):874–879. DOI: 10.3109/00016357.2014.919664.

2. Imbery TA, Namboodiri A, Duncan A, et al. Evaluating dentin surface treatments for resin-modified glass ionomer restorative materials. Oper Dent 2013;38(4):429–438. DOI: 10.2341/12-162-L.

3. Hamama HH, Burrow MF, Yiu C. Effect of dentine conditioning on adhesion of resin-modified glass ionomer adhesives. Aust Dent J 2014;59(2):193–200. DOI: 10.1111/adj.12169.

4. Tanumiharja M, Burrow MF, Tyas MJ. Microtensile bond strengths of glass ionomer (polyalkenoate) cements to dentine using four conditioners. J Dent 2000;28(5):361–366. DOI: 10.1016/s0300-5712(00)00009-9.

5. Beech DR, Solomon A, Bernier R. Bond strength of polycarboxylic acid cements to treated dentine. Dent Mater 1985;1(4):154–157. DOI: 10.1016/s0109-5641(85)80009-9.

6. Rai N, Naik R, Gupta R, et al. Evaluating the effect of different conditioning agents on the shear bond strength of resin-modified glass ionomers. Contemp Clin Dent 2017;8(4):604–612. DOI: 10.4103/ccd.ccd_631_17.

7. Tay FR, Smales RJ, Ngo H, et al. Effect of different conditioning protocols on adhesion of a GIC to dentin. J Adhes Dent 2001;3(2):153–167.

8. Cardoso MV, Delmé KIM, Mine A, et al. Towards a better understanding of the adhesion mechanism of resin-modified glass-ionomers by bonding to differently prepared dentin. J Dent 2010;38(11):921–929. DOI: 10.1016/j.jdent.2010.08.009.

9. Alkhudhairy F, Naseem M, Ahmad ZH, et al. Efficacy of phototherapy with different conventional surface treatments on adhesive quality of lithium disilicate ceramics. Photodiagnosis Photodyn Ther 2019;25:292–295. DOI: 10.1016/j.pdpdt.2019.01.015.

10. Alkhudhairy F, Vohra F, Naseem M. Influence of Er,Cr:YSGG laser dentin conditioning on the bond strength of bioactive and conventional bulk-fill dental restorative material. Photobiomodulation Photomedicine Laser Surg 2020;38(1):30–35. DOI: 10.1089/photob.2019.4661.

11. Alkhudhairy F, Naseem M, Ahmad ZH, et al. Influence of photobio-modulation with an Er,Cr:YSGG laser on dentin adhesion bonded with bioactive and resin-modified glass ionomer cement. J Appl Biomater Funct Mater 2019;17(4):2280800019880691. DOI: 10.1177/2280800019880691.

12. Vohra F, Labban N, Al-Hussaini A, et al. Influence of Er;Cr:YSGG laser on shear bond strength and color stability of lithium disilicate ceramics: an in vitro study. Photobiomodulation Photomedicine Laser Surg 2019;37(8):483–488. DOI: 10.1089/photob.2018.4582.

13. Alkhudhairy F, Al-Johany SS, Naseem M, et al. Dentin bond strength of bioactive cement in comparison to conventional resin cement when photosensitized with Er,Cr:YSGG laser. Pakistan J Med Sci 2019;36(2):85–90. DOI: 10.12669/pjms.36.2.1284.

14. Vohra F, Alghamdi A, Aldakkan M, et al. Influence of Er:Cr:YSGG laser on adhesive strength and microleakage of dentin bonded to resin composite in-vitro study. Photodiagnosis Photodyn Ther 2018;23:342–346. DOI: 10.1016/j.pdpdt.2018.08.002.

15. Alkhudhairy F, Alkheraif A, Bin-Shuwaish M, et al. Effect of Er,Cr:YSGG laser and ascorbic acid on the bond strength and microleakage of bleached enamel surface. Photomed Laser Surg 2018;36(8):431–438. DOI: 10.1089/pho.2018.4437.

16. Alkhudhairy F, Naseem M, Bin-Shuwaish M, et al. Efficacy of Er Cr:YSGG laser therapy at different frequency and power levels on bond integrity of composite to bleached enamel. Photodiagnosis Photodyn Ther 2018;22:34–38. DOI: 10.1016/j.pdpdt.2018.02.019.

17. Sirisha K, Rambabu T, Shankar YR, et al. Validity of bond strength tests: a critical review: part I. J Conserv Dent 2014;17(4):305–311. DOI: 10.4103/0972-0707.136340.

18. Sirisha K, Rambabu T, Ravishankar Y, et al. Validity of bond strength tests: a critical review-part II. J Conserv Dent 2014;17(5):420–426. DOI: 10.4103/0972-0707.139823.

19. De Souza-Gabriel AE, Do Amaral FLB, Pécora JD, et al. Shear bond strength of resin-modified glass ionomer cements to Er:YAG laser-treated tooth structure. Oper Dent 2006;31(2):212–218. DOI: 10.2341/05-13.

20. Trajtenberg CP, Pereira PNR, Powers JM. Resin bond strength and micromorphology of human teeth prepared with an Erbium:YAG laser. Am J Dent 2004;17(5):331–336.

21. Palma-Dibb RG, De Castro CG, Ramos RP, et al. Bond strength of glass-ionomer cements to caries-affected dentin. J Adhes Dent 2003;5(1):57–62.

22. Hibst R, Keller U. Experimental studies of the application of the Er:YAG laser on dental hard substances: I. Measurement of the ablation rate. Lasers Surg Med 1989;9(4):338–344. DOI: 10.1002/lsm.1900090405.

23. Visur SR, Gilbert JL, Wright DD, et al. Shear strength of composite bonded to Er:YAG laser-prepared dentin. J Dent Res 1996;75(1):599–605. DOI: 10.1177/00220345960750011401.

24. Garbui BU, De Azevedo CS, Zezell DM, et al. Er,Cr:YSGG laser dentine conditioning improves adhesion of a glass ionomer cement. Photomed Laser Surg 2013;31(9):453–460. DOI: 10.1089/pho.2013.3546.

25. Jordehi AY, Ghasemi A, Zadeh MM, et al. Evaluation of microtensile bond strength of glass ionomer cements to dentin after conditioning with the Er,Cr:YSGG laser. Photomed Laser Surg 2007;25(5):402–406. DOI: 10.1089/pho.2006.2074.

26. Pereira PN, Yamada T, Tei R, et al. Bond strength and interface micromorphology of an improved resin-modified glass ionomer cement. Am J Dent 1997;10(3):128–132.

27. Hotz P, McLean JW, Sced I, et al. The bonding of glass ionomer cements to metal and tooth substrates. Br Dent J 1977;142(2):41–47. DOI: 10.1038/sj.bdj.4803864.

28. Hinoura K, Miyazaki M, Onose H. Dentin bond strength of light-cured glass-ionomer cements. J Dent Res 1991;70(12):1542–1544. DOI: 10.1177/00220345910700121301.

29. Terata R, Nakashima K, Yoshinaka S, et al. Effect of dentin treatment with citric acid/ferric chloride solutions on glass ionomer bond strength. Am J Dent 1998;11(1):33–35.

30. Powis DR, Follerås T, Merson SA, et al. Improved adhesion of a glass ionomer cement to dentin and enamel. J Dent Res 1982;61(12):1416–1422. DOI: 10.1177/00220345820610120801.

31. Bogra P, Kaswan S. Etching with EDTA–an in vitro study. J Indian Soc Pedod Prev Dent 2003;21:79–83.

32. Poggio C. Effects of dentin surface treatments on shear bond strength of glass-ionomer cements. Ann Stomatol (Roma) 2014;5(1):15–22. DOI: 10.11138/ads/2014.5.1.015.

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