This study evaluated nanoleakage at the interface between dental enamel, leucite-reinforced ceramic, and four different resin luting systems. Bovine teeth were divided into four groups based on the luting procedure used: Excite adhesive with Variolink II cement, Clearfil SE Bond with Panavia F cement, Scotchbond Multi-Purpose Plus with RelyX ARC cement, or Single Bond 2 with Filtek Z350 Flow composite. Specimens were immersed in silver nitrate and examined under SEM. The Single Bond 2/Filtek Z350 Flow group showed no nanoleakage at the enamel interface. The Excite/Variolink II group had the highest nanoleakage

1. MICROSCOPY RESEARCH AND TECHNIQUE 00:000–000 (2011)
Nanoleakage Evaluation of Resin Luting Systems to Dental
Enamel and Leucite-Reinforced Ceramic
´ ´ ´ ´ ´
LUCIA TRAZZI PRIETO,1 EDUARDO JOSE SOUZA-JUNIOR,2 CINTIA TEREZA PIMENTA ARAUJO,1,4
´
ADRIANO FONSECA LIMA,1 CARLOS TADEU DIAS,3 AND LUIS ALEXANDRE MAFFEI SARTINI PAULILLO1*
1
Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, SP-Brazil, Avenida Limeira, 901,
Areiao, 13414-903, Piracicaba, SP, Brazil
˜
2
Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, State University of Campinas, SP-Brazil
Avenida Limeira, 901, Areiao, 13414-903, Piracicaba, SP, Brazil
˜
3
Department of Statistical Mathematics, Luiz de Queiroz Higher School of Agriculture of the University of Sao Paulo (Esalq/USP),
˜
´
Avenida Padua Dias, 11—Piracicaba, SP, Brazi
4
Department of Dentistry, Faculty of Sciences of Health, Federal University of Jequitinhonha and Mucuri Valley -UFVJM, Diamantina,
Minas Gerais, Brazil
KEY WORDS ceramic; adhesive system; enamel; nanoleakage; resin cement
ABSTRACT Purpose: The aim of this study was to evaluate the nanoleakage patterns between
dental enamel and reinforced leucite ceramic, bonded with resin luting systems and a flowable
composite resin. Materials and Methods: Twelve crowns of bovine incisors were randomly divided
into four groups (n 5 3) according to the luting procedure: Excite/Variolink II, Clearfil SE Bond/
Panavia F, Scotchbond Multi-Purpose Plus/RelyX ARC, and Single Bond 2/Filtek Z350 Flow. To
evaluate the nanoleakage patterns, IPS Empress Esthetic disks (5 mm Ø and 1.2-mm thick) were
bonded to enamel, and, after 24 h, the specimens were immersed in a 50% (w/v) solution of silver
nitrate (24 h), fixed, dehydrated, and processed scanning electron microscopy (SEM). Results: None
nanoleakage on interface of the groups that Single Bond 2 followed by the flowable composite were
used. The highest percentage of nanoleakage was shown by the Excite/Variolink II protocol. Also,
in all conditions tested, none silver nitrate uptake was observed between the leucite-reinforced ce-
ramic and the resin luting cement. Conclusions: The use of a two-step etch-and-rinse adhesive
with flowable composite was able to promote an adequate seal of the bond interface at the enamel.
Moreover, the conventional dual-cured resin cements associated with simplified and dual-cured
adhesives tested are also indicated to bond thin ceramics to enamel, since all presented low silver
nitrate uptake. Microsc. Res. Tech. 00:000–000, 2011. V 2011 Wiley Periodicals, Inc.
C
INTRODUCTION 2008) Also, solvated bonding systems can compromise
With the development of the adhesive dentistry, the quality of the hybrid layers, due to the inferior
resin luting strategies have been widely used to bond polymer matrix formed, decreasing the bonding per-
indirect restorations to tooth structures. In this way, formance to dental substrate (Carrilho et al., 2009; Tay
the dual-cured resin system aims to improve the poly- et al., 2003).
merization through the indirect restorations, since the To evaluate the sealing ability of restoration by adhe-
light attenuation caused by the ceramic can jeopardize sive material and the quality of the polymer formed,
the degree of conversion of the luting materials. How- nanoleakage is an important indicator (Sano et al.,
ever, the dual resin cements may have the original 1995). Based mainly on this technique, many studies
color changed, due to oxidation of the amine compo- evaluating nanoleakage patterns for several bonding
nent. This fact can compromise the final esthetic systems (and their influence on bonding parameters)
appearance of the restoration, especially in cases of have been performed (Makishi et al., 2010; Reis et al.,
thin ceramic veneers (Karaagaclioglu and Yilmaz, 2007, 2010). Silver nitrate has been accepted as a suit-
2008). To avoid this, some authors have suggested lut- able method for measuring interfacial leakage (Mala-
ing thin ceramic veneers with flowable resin compo- carne-Zanon et al., 2010; Reis et al., 2007; Sano et al.,
sites (Moon et al., 2002). Flowable composites are light- 1995) due to the size of the silver ion dyes (0.059-nm di-
cured materials, with a lower amount of amine coini- ameter) compared to the size of a typical bacterium
tiators, which may not affect the final esthetic appear- (0.5–1.0 nm). The small size of particles and the high,
ance of the ceramic restoration over time. binding tightly to any exposed collagen fibrils not
The resinous luting approach traditionally requires
the use of adhesive agents, which can be either total-
´
*Correspondence to: Prof. Dr. Luıs Alexandre Maffei Sartini Paulillo, Depart-
etching or self-etching systems. The bond systems pre- ment of Restorative Dentistry, Piracicaba School of Dentistry, State University of
senting a hydrophobic resin layer, such as the three- ˜
Campinas—UNICAMP, Av: Limeira—Areiao. CEP: 13414-903, Piracicaba, SP,
Brazil. E-mail: lapaulillo@gmail.com
step etch-and-rinse and two-step self-etch, can
Received 29 May 2011; accepted in revised form 26 September 2011
decrease the adhesive film permeability, favoring bond DOI 10.1002/jemt.21110
stability over time (Carrilho et al., 2009; Reis et al., Published online in Wiley Online Library (wileyonlinelibrary.com).
V
C 2011 WILEY PERIODICALS, INC.

2. 2 L.T. PRIETO ET AL.
TABLE 1. Resin cements used in the study with composition and manufacturer’s information
Resin cements Composition Manufacturer
Variolink II (Batch Base: Bis-GMA, UDMA and TEGDMA, barium glass, ytterbium trifluoride, glass Ivoclar Vivadent,
#01441) fluorsilicate barium and aluminum oxides mixed spheroid. Catalyst: Bis-GMA, UDMA Schaan,
and TEGDMA, ytterbium trifluoride, glass and aluminum fluorsilicate barium and Lietchtestein
spheroid mixed oxide, benzoyl peroxide, stabilizer.
RelyX ARC (Batch Paste A: Silane treated ceramic, Bis-GMA, TEGDMA, photoinitiators, amine, silane 3M ESPE, St Paul,
#GU9JG) treated silica, functionalized dimethacrylate polymer. Paste B: silane treated ceramic, Minesota, USA
TEGDMA, Bis-GMA, silane treated silica, benzoil peroxide, functionalized
dimethacrylate polymer.
Filtek Z350 flow Matrix: BisGMA, TEGDMA, dimethacrylate polymer. Fillers: 47% zirconia/sılica ´ 3M ESPE, St Paul,
(Batch:#N124855) fillers Minesota, USA
Panavia F (Batch Paste A: 10-MDP, hydrophobic aromatic dimethacrylate, hydrophobic aliphatic Kuraray Medical,
#00027B) ´
dimethacrylate, hydrophilic dimethacrilate, silanated sılica, photoinitiators, dl- Tokyo, Japan
camphoroquinone, benzoil peroxide. Paste B: hydrophobic aromatic dimethacrylate,
hydrophobic aliphatic dimethacrylate, hydrophilic dimethacrylate. Sodium aromatic
sulfinate, accelerator, sodium fluoride, silanated barium glass.
TABLE 2. Adhesive systems used in the study with composition and manufacturer’s information
Adhesive systems Composition Manufacturer
ED Primer (Batch #01441) Primer A (Batch #00272A): 2-hydroxyethyl methacrylate (HEMA), MDP, Kuraray Medical,
NM-aminosalicylic acid, diethanol-p-toluidine, water. Primer B (Batch Tokyo, Japan
#00147A): NM-aminosalicylic acid, T-isopropilic benzenic sodium sulfinate,
diethanol-p-toluidine, water
Excite (Batch #1177) Phosphonic acid acrylate, HEMA, Bis-GMA, methacrylates, silicon dioxide, Ivoclar Vivadent,
ethanol, catalysts and stabilizers Schaan,
Lietchtestein
Adper Single Bond 2 Dimethacrylates, HEMA, Polyalkenoid acid copolymer, 5-nm silane-treated 3M ESPE, St Paul,
(Batch #9XB) colloidal silica, ethanol, water, photoinitiator Minesota, USA
Clearfil SE Bond Primer (Batch #00896A): water, MDP, HEMA, camphorquinone, hydrophilic Kuraray Medical
dimethacrylate. Adhesive (Batch #01320A): MDP, bis-GMA, HEMA, Inc., Tokyo, Japan
camphorquinone, hydrophobic dimathacrylate, N,N-diethanol p-toluidine bond,
colloidal silica.
Adper Scotchbond Multi Primer:HEMA, water, copolymer of polycarboxilic acid. Adhesive: Bis-GMA, 3M ESPE, St Paul,
Purpose (Batch #356B) HEMA, polyalkenoic acid copolymer, CQ, EDMAB, DHEPT. Minesota, USA
enveloped by the adhesive resin, makes silver nitrate F (CSE/PN—Kuraray, Tokyo, Japan); G3—Adper
the most appropriate agent to detect the nanoporosities Scotchbond Multi-Purpose Plus/RelyX ARC (SBMP/
within the hybrid layer (Carrilho et al., 2007). RX—3M/ESPE, St Paul, MN); G4—Adper Single Bond
As there is no ideal material to bond indirect restora- 2/Filtek Z350 Flow (SB/FL—3M/ESPE). The composi-
tions to enamel, appropriate selection of these resin tion of the resin cements and adhesive systems are
luting systems, according to the different clinical situa- listed in Tables 1 and 2. The adhesive systems and
tions, is required. Thus, the aim of this study was to resin cements were applied following manufacturer’s
evaluate the nanoleakage patterns of resin luting sys- instructions, and are described in Table 3.
tems, bonded to dental enamel and leucite-reinforced Ceramic disks (5-mm diameter, 0.6-mm-thick leu-
ceramic. The hypothesis tested was that the flowable cite-reinforced ceramic, and 0.6-mm-thick feldspar ce-
composite would provide an effective seal for veneer ce- ramic, totaling a ceramic specimen 1.2-mm thick) were
ramic cementation compared to the dual-cured resin etched for 60 s using a 10% hydrofluoridric acid
cements. (Dentsply Caulk, Midford, DE), followed by silane
(Monobond S, Ivoclar Vivadent, Schaan, Lietschestein)
MATERIALS AND METHODS application for 60 s. The specimens were bonded to
Specimen Preparation enamel surface, according to the manufacturer’s
instructions.
Twelve bovine incisors were selected, cleaned, and
stored in 0.01% thymol solution at 378C for 2 weeks.
The root was sectioned using a low-speed, double-faced Nanoleakage Evaluation
diamond saw (Isomet 1000, Buehler, Lake Bluff, IL). After 24 h of the luting procedure, specimens were
The buccal surface was ground flat with 400-, 600-, and longitudinally sectioned using a diamond saw. Next,
1,200-grit aluminum oxide papers (Carborundum, each specimen was immersed in a 50% ammoniac sil-
Saint-Gobain Abrasives, Guarulhos, SP, Brazil), under ver nitrate solution for 24 h in the dark at 378C (Tay
constant water-cooling. Next, the specimens were ran- et al., 2002). Afterward, the specimens were thor-
domly distributed in experimental groups according to oughly rinsed in distilled water for 2 min and
the luting procedures (adhesive systems/resin cement): immersed in a photo-developing solution for 8 h (Kodak
G1—Excite /Variolink II (EX/VR—Ivoclar-Vivadent, Developer D--76-Kodak Brasileira Ind. e Com Ltda.,
Schaan, Lietschestein); G2—Clearfil SE Bond/Panavia Sao Jose dos Campos, SP, Brazil) under fluorescent
Microscopy Research and Technique

3. BONDING AND LEAKAGE TO ENAMEL/CERAMICS INTERFACE 3
TABLE 3. Procedures for cementing systems adhesion ished sequentially with aluminum oxide papers (600-,
Luting systems Procedures for cementing 1,200-, and 2,000-grit) and felt disc with diamond paste
of decreasing grain (3.1 and 0.25 lm) using a metallo-
Adhesive system 1) Acid etching of enamel with 35%
phosphoric acid (15 s) and washing with
graphic polisher (PL02, Arotec Equip, SP, Brazil). The
distilled water for 15 s specimens were immersed in distilled water and placed
Excite 2) Application of the adhesive system on in ultrasonic baths (Ultrasone D 1440—Odontobras ´
enamel Ind. E Com Med Odont. Ltda., Rio Preto, Brazil) for 10
Resin cement 3) Mild air stream
Variolink 4) Light curing for 20 s
min, after each step of the polishing procedure.
(Ivoclar-Vivadent) 5) Mix of resin cement pastes (base 1 Next, the specimens were dried with absorbent
catalyst for 15 s) papers and immersed in a solution of 50% phosphoric
6) Light curing for 40 s. acid for 10 s, followed by rinsing in distilled water. For
Adhesive system 1) Primer application on enamel surface
(Clearfil SE Bond) for 30 s
deproteinization, a 10% solution of sodium hypochlo-
Clearfil SE bond 2) Bond application (Clearfil SE Bond) and rite was used for 10 min. After this, the specimens
light curing for 10 s were rinsed and dried at room temperature (2 h) and
ED primer 3) Application of the primer (Clearfil SE dehydrated with ethanol at increasing concentrations
Bond) 1 Porcelain Bond Activator mix for
1 minute on ceramic surface for 1 min.
of 25, 50, 75, 90, and 100%, for 10-min each. The speci-
Resin cement 4) Mix of ED Primer A e B, and application mens were carbon coated (Bal-Tec SCD-050—Sputter-
on the adhesive layer on enamel Coater) and analyzed in a scanning electron micro-
Panavia F 5) Mix of resin cement (20 s) scope (SEM—JEOL JSM—V 5600 LV, Tokyo, Japan),
(Kuraray) 6) Light curing for 40 s
Adhesive system 1) Acid etching with 35% phosphoric acid at 15 kV. The images of silver-infiltrated specimens
(15 s), and washing with distilled water were taken to calculate the marked area using com-
(15 s) puter software Image Tool 3.0 (University of Texas,
Scotchbond 2) Application of Activador Scotchbond and Health Science Center at San Antonio, TX). The inter-
multi-uso Plus mild air stream (5 s)
Resin cement 3) Application of primer agent and air spray face length between enamel/adhesive and ceramic/
(5 s) resin cement was measured, and the percentage of the
RelyX ARC 4) Catalyst application in ceramic surface infiltrated area calculated.
and enamel
(3M/ESPE) 5) Mix of the resin cement (10 s)
6) Light curing for 40 s.
Adhesive system 1) Acid etching with 35% phosphoric acid RESULTS
(15 s), and washing with distilled water Nanoleakage Patterns
for 15 s
Single bond 2) Application of two consecutives layer of Descriptive analysis of the nanoleakage patterns
adhesive system was performed, as SEM evaluation showed a low per-
Resin Filtek Flow 3) Light curing for 10 s centage of silver nitrate uptake; in most situations it
(3M/ESPE). 4) Application of the flowable resin
5) Light curing for 40 s. was 0%, excluding the statistical analysis. After analy-
sis of the bonding interface between ceramic and resin
cement, none nanoleakage was observed in any speci-
mens. Figures 1–4 show the bonded interface with sil-
ver nitrate uptake (magnification 3200 and 31,400).
light, to reduce silver ions to metallic silver grains Table 4 shows the percent values of nanoleakage at the
along bonded interface, adhesive resin, and cement enamel/adhesive interface. The association of Excite/
polymeric structure. Then, the stained specimens were Variolink showed higher silver nitrate uptake under
embedded in a polystyrene resin, and were wet-pol- the adhesive layer (Fig. 1), followed by Clearfil SE
Fig. 1. SEM photomicrography showing nanoleakage for the luting system Excite/Variolink II. (A)
Can be noted as a silver deposition between the enamel and adhesive layer (arrows—3200). (B) Region
with the silver infiltrated in the adhesive layer (31,400).
Microscopy Research and Technique

4. 4 L.T. PRIETO ET AL.
Fig. 2. (A) Few points of silver deposition can be observed in the interface of Clearfil SE/Panavia
(arrows—3200). (B) Region with the silver infiltrated points in the adhesive layer (arrows—31,400).
Fig. 3. (A) Interface Scotchbond MP Plus/ RelyX ARC showing silver deposition in few regions
(arrows—3200). (B) The silver infiltrated can be noted in increased magnification (arrows—31,400).
Fig. 4. (A and B) Absence of silver deposition in the interface of flowable resin even in high magnifi-
cation (3200 and 31,400).
Microscopy Research and Technique

5. BONDING AND LEAKAGE TO ENAMEL/CERAMICS INTERFACE 5
TABLE 4. Percentual of silver nitrate uptake at the tested groups The high concentration of hydrophobic monomers
Luting system Silver nitrate uptake (BisGMA and UDMA) in EX, viscous monomers with
high molecular weight (Van Landuyt et al., 2007), com-
Clearfil SE bond/Panavia F 2.30%
Excite/Variolink 15.10%
bined with the low concentration of diluents (HEMA)
Scotchbond multi purpose /RelyX ARC 2.20% and solvent (ethanol), increase the viscosity of this ad-
Single bond 2/Filtek Z350 Flow 0 hesive, which can reduce the diffusion of the adhesive
to the microretention, decreasing the quality of adhe-
sive interlocking, and, consequently, compromises the
sealing ability of the adhesive.
Bond/Panavia F and Scotchbond Multi-Purpose Plus/ The three-step etch-and-rinse and the two-step self-
RelyX ARC, which show few points of silver nitrate etch adhesives tested present a high amount of hydro-
penetration in the adhesive layer (Figs. 2 and 3). The phobic monomers on the bond agent, which could com-
flowable composite did not present nanoleakage pat- promise sealing as with the EX. However, the primer
terns on the bond interface (tooth/adhesive; Fig. 4). application improves the bond penetration into the
etched surface, which might explain the results
obtained for the SBMP and CSE adhesives.
DISCUSSION The present study showed that the flowable compos-
The luting systems selected for this study are suita- ite resin associated with a simplified two-step etch-
ble for fixing ceramic with different compositions. How- and-rinse bond system promotes better sealing of the
ever, the dual-cure resin cements can cause color alter- ceramic–tooth interface, an important factor for the
ation, due to the oxidation of the tertiary amine, lead- longevity of tooth veneers. In light of these facts, the
ing to color change of the prosthetic restorations use of flowable resins to bond ceramic laminates should
(especially thin ceramic veneers), compromising the es- be considered, as this material can provide both
thetic appearance (Ghavam et al., 2010). Moreover, adequate sealing and color stability.
some manufacturers of flowable composite resin recom-
mend this resin for luting thin indirect restorations. In CONCLUSIONS
light of these facts, the objective of the present study
was to compare the adhesive/flowable composite resin The luting agents associated with the adhesive sys-
efficacy, a color-stable material, with different dual- tems showed high quality of the bonding to enamel and
cure luting systems, used for indirect restorations. few points of silver nitrate infiltration on the adhesive
When the nanoleakage patterns between the leucite- interface. The flowable resin is an alternative to luting
reinforced ceramic and the resinous cements were eval- thin ceramic veneers to enamel, promoting adequate
uated, no silver-tracing solution was found. This might sealing between ceramic and tooth substrate.
be explained by the fact that some ceramic surface
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