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To evaluate the influence of different surface treatments on the microtensile bond strength of resin cement to zirconia ceramic. Twelve cylinder-shaped (∅ 12×5.25 mm high) blocks of a commercial zirconium-oxide ceramic (Cercon® Zirconia, DENTSPLY) were randomly divided into 4 groups (n=3), based on the surface treatment to be performed: (1) airborne particle abrasion with 125 μm Al₂O₃ particles (S); (2) selective infiltration etching (SIE); (3) experimental hot etching solution applied for 30 min (ST) and (4) no treatment (C). Paradigm MZ100 blocks (3M ESPE) were cut into twelve cylinders of 4mm in thickness. Composite cylinders were bonded to conditioned ceramics using a resin cement (Calibra®, DENTSPLY), in combination with the proprietary adhesive system. After 24h bonded specimens were cut into microtensile sticks and loaded in tension until failure. Bond strength data were analyzed with Kruskall-Wallis and Dunn's Multiple Range test for multiple comparisons (p < 0.05). Failure mode distribution was recorded and the interfacial morphology of debonded specimens was analyzed using a scanning electron microscope (SEM). Bond strength values achieved after SIE and ST treatment were significantly higher than after S treatment and without any treatment (p < 0.05). Premature failures were mostly recorded in the S group. Conditioning the high-strength ceramic surface with SIE and ST treatments yielded higher bond strengths of the resin cement than when zirconia ceramic was treated with airborne particle abrasion or left untreated.
dental materials 27 (2011) 1024–1030
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Effect of surface pre-treatments on the zirconia
ceramic–resin cement microtensile bond strength
Alessio Casuccia, Francesca Monticellib, Cecilia Goraccia, Claudia Mazzitellia,
Amerigo Cantoroa, Federica Papacchinia, Marco Ferraria,
aDepartment of Fixed Prosthodontics and Dental Materials, University of Siena, Siena, Italy
bDepartment of Surgery, Faculty of Health and Sport Sciences, University of Zaragoza, Huesca, Spain
article info
Article history:
Received 9 June 2010
Received in revised form
22 April 2011
Accepted 4 July 2011
Zirconia ceramic
Surface treatment
Bond strength
Resin cement
Objective. To evaluate the influence of different surface treatments on the microtensile bond
strength of resin cement to zirconia ceramic.
Materials and methods. Twelve cylinder-shaped (12×5.25 mm high) blocks of a commer-
cial zirconium-oxide ceramic (Cercon®Zirconia, DENTSPLY) were randomly divided into 4
groups (n= 3), based on the surface treatment to be performed: (1) airborne particle abrasion
with 125 mAl
2O3particles (S); (2) selective infiltration etching (SIE); (3) experimental hot
etching solution applied for 30 min (ST) and (4) no treatment (C). Paradigm MZ100 blocks (3M
ESPE) were cut into twelve cylinders of 4mm in thickness. Composite cylinders were bonded
to conditioned ceramics using a resin cement (Calibra®, DENTSPLY), in combination with the
proprietary adhesive system. After 24h bonded specimens were cut into microtensile sticks
and loaded in tension until failure. Bond strength data were analyzed with Kruskall–Wallis
and Dunn’s Multiple Range test for multiple comparisons (p<0.05). Failure mode distribution
was recorded and the interfacial morphology of debonded specimens was analyzed using a
scanning electron microscope (SEM).
Results. Bond strength values achieved after SIE and ST treatment were significantly higher
than after S treatment and without any treatment (p<0.05). Premature failures were mostly
recorded in the S group.
Significance. Conditioning the high-strength ceramic surface with SIE and ST treatments
yielded higher bond strengths of the resin cement than when zirconia ceramic was treated
with airborne particle abrasion or left untreated.
© 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
1. Introduction
The use of partially stabilized zirconium dioxide ceramics
to fabricate metal-free esthetic restorations has increased
in recent years, thanks to their excellent physical prop-
erties and optimal biocompatibility [1–6]. Several studies
Corresponding author at: Department of Fixed Prosthodontics and Dental Materials, University of Siena, Policlinico “Le Scotte”, Viale
Bracci 1, 53100 Siena, Italy. Tel.: +39 0577233131; fax: +39 0577233117.
E-mail addresses:,, (M. Ferrari).
reported that zirconia-based ceramics may achieve bet-
ter mechanical resistance than feldspathic, leucite, and
lithium disilicate ceramics, especially when restoring poste-
rior teeth [7–13]. Clinically, chipping of veneering porcelains
and loss of retention are the most frequently reported
complications of zirconia-based ceramics [14]. Particularly,
poor retention may be ascribed to incorrect tooth prepara-
0109-5641/$ see front matter © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
dental materials 27 (2011) 1024–1030 1025
tion and inadequate luting technique or cement selection
Although zirconia restorations can be cemented with zinc
phosphate or modified glass-ionomer cements [17], it has been
reported that resin-based luting agents are the most appro-
priate materials for the purposes of marginal seal, retention,
and fracture resistance [18]. Resin cements containing 10-MDP
(10-methacryloyloxydecyl dihydrogen phosphate) have been
considered as the materials of choice, since the phosphate
ester monomers are capable of a chemical interaction with
the hydroxyl groups of the ZrO2ceramic [18,19].
Previous studies have investigated different chemo-
mechanical surface treatments aimed at optimizing the
cement/zirconia bonding mechanism [20–23]. The rationale
of these conditioning processes lies in increasing the sur-
face area available for bonding to obtain strong and durable
restorations [24–26]. Sandblasting has been widely applied for
increasing ceramics surface roughness and thus the surface
area available for bonding. Up to date, the combination of
sandblasting and 10-MDP monomer based resin is the recom-
mended method of bonding to zirconia frameworks [27–30].
However, the outcome of this procedure may be affected
by variables such as particle size and application distance.
Particularly, excessive particle size and reduced application
distance may induce crack initiation, possibly reducing the
ceramic long-term mechanical properties [31–34].
Novel surface treatments have been proposed in order
to improve zirconia/resin cement bonds, such as the selec-
tive infiltration etching (SIE). This treatment is based on the
application of a low viscosity melting glass on the surface of
zirconia, that create abraded and porous surfaces improving
bond strength [35].
More recently, an experimental hot chemical etching solu-
tion (ST), composed by HCl and Fe2Cl3in methanol, previously
used for conditioning metal and/or alloys has been applied on
zirconia ceramics with the result of improving their average
surface roughness [36–38]. However, it has not yet been veri-
fied whether such increase in superficial roughness promotes
the adhesion of the luting agent.
Therefore, the aim of this study was to evaluate the influ-
ence of different surface treatments on the bond strength
between a commercially available partially-stabilized zirco-
nia ceramic and a resin cement. The tested null hypothesis
was that there were no statistically significant differences
in the microtensile bond strengths measured at the zir-
conia ceramic–resin cement interface following different
pre-treatments of the zirconia ceramic surface.
2. Materials and methods
Twelve cylinder-shaped (12mm diameter, 5.25 mm height)
Cercon®zirconia sintered ceramic blocks (DETREY DENTSPLY
Ceramco, York, USA) were used for the study. Specimens were
polished with SiC abrasive papers (grit # 600, 1000, 1200 and
2000). Final polishing was carried out on nylon cloths using 1-
and 0.50 m grit diamond pastes. Specimens were sonicated
in deionized water for 5 min and randomly assigned to four
equally sized experimental groups, according to the surface
treatment performed on zirconia:
(1) Selective infiltration etching procedure. Specimens were
coated with a thin layer of an infiltrating agent contain-
ing low temperature melting glass and additives (SiO2
(65 wt.%); Na2O (15 wt.%); Al2O3(8 wt.%); Li2O (3 wt.%); B2O3
(4 wt.%); CaF2(5 wt.%)). They were heated up to 750C for
1 min using a computer-programmed electrical induction
furnace (Austromat 3001; Dekema Dental-Keramikofen,
Freilassing, Germany), cooled reaching 650C for 1 min,
heated again up to 750 C for 20 min (increasing T intervals
60 C/min), and finally cooled at room temperature. Rem-
nants of the infiltrating agent were dissolved immersing
ceramic discs in an ultrasonic bath with 5% hydrofluoric
acid solution for 30 min (SIE) [31].
(2) Experimental etching solution. A hot acidic solution contain-
ing HCl and Fe2Cl3in methanol was heated up to 100C.
The zirconia specimens were immersed in the solution for
30 min (ST) [36,37].
(3) Sandblasting with 125mAl
2O3particles for 10 s at
0.4–0.7 MPa from a distance of 20mm (S).
(4) No pretreatment (C).
Conditioned specimens were rinsed with tap water for 1min,
ultrasonically cleaned in a deionized water bath for 30 min and
gently air-dried.
Resin composite blocks (Paradigm MZ100, 3M ESPE, size
14; batch # 20060213) were cut by means of a water-cooled
diamond saw (Isomet 1000, Buelher, Lake Bluff, IL) into 12
cylinders of 4 mm in height.
The intaglio surface of each composite block was ground
with 180-grit SiC paper, cleaned with ethanol and gently air-
A dual-cure resin cement (CalibraTM DeTrey DENTSPLY;
batch # 080910) was used in combination with the proprietary
adhesive (XP Bond, DENTSPLY, batch # 0810003096) for luting
the composite disc to the conditioned ceramic surface. The
resin composite surface was etched with 37% phosphoric for
15 s, washed thoroughly for 1 min under tap water. Then a thin
layer of adhesive (XP bond Adhesive) was applied on zirconia
and composite surfaces, it was dried with a gentle airflow and
polymerized for 20 s. Zirconia and composite blocks were luted
using a resin luting material (Calibra) that was applied on zir-
conia surface; a seating pressure of 1 kg was maintained over
the specimens during the first 5 min of cement autocure.
Then, light irradiation (Vip, Bisco, Schaumburg, Illinois,
USA; Output: 500 mW/cm2) was performed for 40 s on each
side of the block to ensure optimal polymerization. Bonded
specimens were stored in a laboratory oven at 37 C and 100%
relative humidity for 24h.
2.1. Microtensile bond strength test
Ceramic–composite bonded specimens were cut vertically into
2 mm-thick slabs with a slow-speed diamond saw (Isomet).
Each slab was serially sectioned into 2.0×2.0mm sticks. From
every ceramic–composite bonded specimen a number of sticks
variable between 16 and 9 was obtained.
Each stick was glued with cianoacrylate (Super Attack gel
Henkel Consumer Adhesives, Avon, Ohio, USA) to the free-
sliding components of a Girardeli’s jig, and loaded in tension
1026 dental materials 27 (2011) 1024–1030
with a universal testing machine (Triax digital 50, Controls,
Milan, Italy) at a cross-head speed of 0.5 mm/min until failure.
Failure modes were evaluated under a stereomicroscope
(Nikon Instrument Group, Melville, NY) at 40×magnifica-
tion and classified as adhesive (between composite and luting
agent or between ceramic and luting agent), cohesive (within
luting agent, composite or ceramic), mixed (adhesive and
cohesive failures occurred simultaneously). As the objective of
the study was to assess the adhesive potential of the cement
to the zirconia substrate, it was decided that adhesive fail-
ures at the cement–composite interface, as well as cohesive
fractures within ceramic or composite should not be consid-
ered in statistical calculations. Also microtensile sticks that
had failed prior to testing were excluded from statistical cal-
culations. The number of microtensile sticks that were tested
in each group is reported in Table 1.
2.2. SEM evaluation
Four fractured sticks were randomly selected from each exper-
imental group and prepared for scanning electron microscope
(SEM) analysis. Each sample was cleaned with 96% ethanol,
mounted on metallic stubs, gold-sputtered (Polaron Range SC
7620, Quorum Technology, Newhaven, UK), and viewed under
the SEM (JSM-6060LV, Jeol, Tokyo, Japan) at different magnifi-
cations, in order to evaluate the fracture pattern.
3. Statistical analysis
As the distribution of microtensile bond strength data was
not normal according to the Kolmogorov–Smirnov test, the
Kruskall–Wallis Analysis of Variance was applied, followed by
the Dunn’s Multiple Range test for multiple comparisons.
The distributions of failures patterns were compared
among the groups using the chi-square test.
In all the statistical analyses the level of significance was
set at ˛= 0.05.
4. Results
4.1. Microtensile bond strength test
Mean bond strength values and standard deviations (SD) of
the tested groups are summarized in Table 2.
The Kruskall–Wallis ANOVA revealed the existence of sig-
nificant between-group differences (p<0.001). According to
the multiple comparisons test, selective infiltration etching
produced a statistically significant increase in the cement
bond strength in comparison with untreated and sandblasted
specimens (p< 0.05). Also the specimens that were treated
with the hot etching solution measured higher cement bond
strengths than those recorded in the ‘sandblasting’ and the
‘no pretreatment group’(p<0.05). However, the difference was
statistically significant only with the ‘no pretreatment’ group
(p< 0.05).
As reported in Table 3 pretest failures were recorded with
similar percentages (5–7%) in the different groups; all of them
occurred at the interface between zirconia and resin cement.
Howeversignificant differences emerged in the distribution
of failure patterns.
Untreated and sandblasted specimens most frequently
failed adhesively at the zirconia–cement interface, while the
majority of specimens treated with SIE and ST exhibited mixed
4.2. SEM analysis
Representative SEM images of fractured beams are reported
in Fig. 1. S group specimens mainly failed adhesively at the
ceramic–cement interface (Fig. 1A). Although surface irreg-
ularities were evident, no resin cement remnants could be
detected on the zirconia surface after load. In SIE and ST
groups mixed failures were prevalent. Resin cement remnants
retained over a roughened zirconia substrate were seen in SEM
images of specimens from SIE and ST groups (Fig. 1B and C,
respectively). Untreated zirconia presented a smooth surface
with only few scratches and cement residuals (Fig. 1D).
5. Discussion
Although zirconium dioxide ceramics are able to withstand
relatively high fracture loads showing optimum strength, their
clinical success also depends on the establishment of a reliable
bond with the luting agent [39,5,40].
According to the achieved results, a significant improve-
ment in zirconia ceramic–resin cement interfacial strength
was recorded after SIE and ST treatments. Thus, the null
hypothesis has to be rejected.
Although there is not enough clinical evidence to support
a specific cementation protocol when dealing with zirconia
restorations [41], the use of resin cements in combination
with preliminary zirconia surface treatments is highly recom-
mended [42].
Ultramorphologic evaluation performed combining SEM
and AFM analysis revealed that different retentive surfaces
and changes in topography may be produced on zirconia
depending on the selected surface treatment [36,37]. These
treatments have been proposed to enhance retention, hence
providing microporosities where the luting agent can pene-
trate and establish a stronger micro-mechanical interlocking
The present study confirmed that differences in surface
pattern after substrate conditioning may affect the retention
of high-strength core ceramics. In particular, SIE and ST treat-
ments resulted in significantly higher cement–ceramic bond
In the present study a conventional bis-GMA-based resin
cement (Calibra) was chosen in order to avoid the chemical
affinity between MDP-based resin cement and the zirconia
ceramic, assessing the real effectiveness of the surface treat-
ments. Although some recent in vitro studies support the use
of Calibra for luting zirconia-based ceramics, the clinical long-
term outcome of this procedure is still to be assessed [45].
Untreated zirconium dioxide ceramic is a relatively inert
substrate with low surface energy and wettability. The high
percentage of adhesive failures and the low bond strength val-
ues recorded in the untreated zirconia group confirmed that
dental materials 27 (2011) 1024–1030 1027
Table1–Materials used in this study.
Materials Manufacturers Main components Batch
Composite blocks paradigm MZ100 3M ESPE 85 wt.% zirconia-silica ceramic particles.
The polymer matrix consists of bisGMA
Resin luting agent CalibraTM DeTrey
Base. Barium boron
fluoroalumino silicate
glass; bis-phenol A
dimethacrylate resin;
hydrophobic amorphous
fumed silica; titanium
Catalyst. Barium boron
fluoroalumino silicate
glass; bis-phenol A
dimethacrylate resin;
hydrophobic amorphous
fumed silica; titanium
dioxide; benzoyl peroxide.
Resin adhesive XP bond DENTSPLY Carboxylic acid modified dimethacrylate
(TCB resin); phosphoric acid modified
acrylate resin (PENTA); Urethane
dimethacrylate (UDMA); triethyleneglycol
dimethacrylate (TEGDMA);
2-hydroxyethylmethacrylate (HEMA);
butylated benzenediol (stabilizer);
camphorquinone; Functionalized
amorphous silica; t-butanol
Groups NMean S.D. Median 25–75% Significance (p< 0.05)
Selective infiltration etching (SIE) 39 23.4 9.6 27.2 13.1–31.2 A
Hot etching solution (ST) 33 22.3 7.8 23.4 14.3–27.8 AB
Sandblasting (S) 27 17.3 8.9 20.1 8.4–24.7 BC
No treatment (C) 27 11.2 4.2 10.9 8.5–14.5 C
Table 2 Descriptive statistics of microtensile bond strength data in MPa. In the ‘Significance’ column different letters
label statistically significant differences according to the post-hoc test.
Groups NMean S.D. Median 25–75% Significance (p< 0.05)
Selective infiltration etching (SIE) 39 23.4 9.6 27.2 13.1–31.2 A
Hot etching solution (ST) 33 22.3 7.8 23.4 14.3–27.8 AB
Sandblasting (S) 27 17.3 8.9 20.1 8.4–24.7 BC
No treatment (C) 27 11.2 4.2 10.9 8.5–14.5 C
Table 3 Distribution of failure patterns in the experimental groups. Groups that had statistically similar failure modes
are labeled with the same symbol (p> 0.05).
Groups Adhesive between
ceramic and cement
Cohesive within cement Mixed Pre-test
Selective infiltration technique (SIE)#Count 7 4 28 7
% 15.2% 8.7% 60.9% 15.2%
Hot etching solution (ST)#Count 8 4 21 7
% 20.0% 10.0% 52.5% 17.5%
Sandblasting (S)§Count 25 0 2 7
% 73.5% 0% 5.9% 20.6%
No treatment (C)§Count 21 0 6 5
% 65.6% 0% 18.8% 15.6%
The simbols “#” and § reported differencies between groups at chi-square test.
1028 dental materials 27 (2011) 1024–1030
Fig. 1 Representative SEM images of the interfacial fracture patterns observed in the different experimental groups (250×,
bar 100 m). (A) Sandblasting, (B) selective infiltration etching; (C) experimental hot etching solution applied for 30 min and
(D) no treatment. Sandblasting resulted in a slightly roughened zirconia surface and was not effective in creating
microretentive spaces. No residues of adhesive and resin cement were detectable on the zirconia surface (A). SIE and ST
treated zirconia surfaces exhibited retained cement remnants after testing (B and C). Untreated zirconia showed a smooth
surface with few scratches probably related to milling procedures (D).
no interaction occurred between Calibra and the zirconia sub-
strate [44]. The absence of adhesive functional monomers in
the cement composition may explain lower chemical bonding
values comparing to MDP monomer based resin [45,46].
On the contrary, differences in surface pattern
after substrate conditioning may influence the bond
strength to the partially stabilized zirconium dioxide
Airborne-particle abrasion of zirconia surface is one of
the most-investigated methods, provides good bond strength
to zirconia when combined with phosphate ester monomer
[40,47,48]. In recent literature it was reported that some vari-
ables such as grain particles size and pressure of application
during sandblasting have an important role on the bonding
capability of resin cements to zirconia substrate [49].Upto
date no consensus is still available regarding the grains size
that may guarantee durable bond strength. Several studies
reported an improvement in zirconia roughness after sand-
blasting with 50–110–125 mAl
2O3particles and encouraging
bond strength values [29,43,50–52]. It was also reported that
smaller particles (30–50 m) may enhance resin cement adhe-
sion [49,53,32].
The relatively low bond strength values achieved on zir-
conia after sandblasting and the remarkable percentage of
adhesive (Fig. 1A) and premature failures revealed that the
treatment did not result in the formation of enough under-
cuts to improve the bond strength. This finding is in agreement
with the results of the study by Oyagüe [43].
A controversial aspect regarding sandblasting procedures
are the effects on mechanical properties of zirconia. It was
reported that sandblasting induce tetragonal to monoclinic (T
to M) phase transformation on zirconia surface that increase
the flexural strength [33,54]. Some authors reported that parti-
cle abrasion of zirconia results in the creation of sharp cracks
and structural defects that render the zirconia framework sus-
ceptible to radial cracking during function [40,55].
Beside the grain size particles, pressure application of
sandblasting was recently evaluated for determining its
effects on zirconia surface. As previously reported for grain
size recent literature suggest different protocols for sand-
blasting. However it was reported that reducing sandblasting
pressure may decrease its detrimental effects on mechani-
cal properties [56]. Thus the relatively high pressure applied
during sandblasting in the present study that potentially
dental materials 27 (2011) 1024–1030 1029
can enhance surface roughness [36,37], did not reveal an
improvement in bond strength. Further mechanical test may
investigate its effect on mechanical properties.
In the present study a modified version of the original SIE
conditioning technique proposed by Aboushelib was used [35].
This procedure is based on the application on the zirconia
surface of an infiltrating agent composed of inorganic oxides.
During the procedure the agent is heated at 750 C and cooled.
Ultimately the infiltration agent remnants are dissolved in a
5% hydrofluoric solution, leaving the zirconia surface condi-
Discrepancies with the findings of a previous investigation
may be related to the use of a modified infiltration glass with
lower silica and higher potassium contents. Varying the glass
percentage in weight may have influenced the melting tem-
perature and, consequently, its effectiveness in infiltrating the
zirconia surface [35].
The ST treatment has been recently proposed as a novel
technique to improve zirconia surface retention [36,37]. The
hot etching solution may determine a selective chemical etch-
ing of zirconia, creating microretentions and enlarging the
grain boundaries through the preferential removal of the less-
arranged, high-energy peripherical atoms [57].
Once the resin composite infiltrates the 3D inter-grain
spaces, it may become structurally integrated with the surface
and higher forces would be necessary to debond it. The sig-
nificantly higher cement–ceramic bond strengths measured
in this study following ST treatment of zirconia confirm this
It should be pointed out that in the present investigation
it was chosen to lute the ceramic blocks onto resin composite
blocks, rather than on teeth for the purpose of standardiza-
tion. It was indeed considered that the dental substrate might
have introduced in the microtensile test a greater source of
variability than a manufactured material such as the compos-
ite blocks [41]. Moreover the chemical affinity due to the same
composition, resin luting agent and composite (Table 1)may
guarantee higher bond strength than to zirconia surface, also
without the application of primers or silanes.
Further in vitro and in vivo studies should be performed to
evaluate the effectiveness of the tested surface treatments
in combination with MDP-based resin luting agents. Such
procedure would complement the benefit of the increased
micromechanical retention produced by zirconia surface
treatment with the contribution of the chemical interaction
mediated by MDP monomers.
6. Conclusions
Within the limitations of this study, it can be concluded
that treating zirconia surfaces with chemical procedures such
as SIE and ST is beneficial for improving the ceramic–resin
cement interfacial strength.
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... Various mechanical and chemical surface treatment methods have been applied to increase the adhesive area and enhance the bond strength of zirconia ceramic and resin cement [7][8][9][10][11]. Sandblasting is the most widely used method for mechanical surface treatment intended to provide roughness to ceramic surfaces. ...
... The chemical etching methods have the advantage that it can produce surface roughness without significantly affecting the properties of the zirconia [25,26]. It has been confirmed that a high-concentration hydrofluoric acid solution mixed with various strong acids increases the roughness of the zirconia surface [8,27]. Zirconia is not etched by HF at room temperature because it is a non-silica-based ceramic [2]. ...
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Background and Objectives: There is no consensus regarding the surface treatment method for achieving optimal bonding strength between zirconia and resin cements. We evaluated the effect of hot-etching with 9% hydrofluoric acid (HF) gel using the Zirconia Etchant Cloud System on zirconia surfaces and the consequent shear bond strength (SBS) of different resin cements to such surface-treated zirconia ceramics. Materials and Methods: Forty-five zirconia specimens were randomly assigned to surface-treatment groups (n = 15/group): no treatment (control, CT); sandblasting with 110-μm Al2O3 at an air pressure of 1 bar for 10 s (SB); hot-etching with 9% HF gel (HE). Post-treatment, specimens were examined using scanning electron microscopy (SEM) and surface roughness (SR) analysis. After treatment, self-adhesive resin cements (Maxcem Elite, MAZIC Cem, RelyX U200, 3M ESPE: Maplewood, MN, USA) were bonded to zirconia specimens, which were stored in distilled water at 37 °C for 24 h. All specimens were then subjected to SBS testing, using a universal testing machine, until failure. Data were analyzed using one-way analysis of variance and Tukey’s post hoc test (α = 0.05). Results: In the SEM images, roughness was greater in SB than in HE specimens. Ra and Rt values were highest in SB, followed by HE, and CT specimens. HE specimens showed significantly higher SBS values than CT or SB specimens (p < 0.05). MAZIC Cem cement, with 10-methacryloyloxydcyl dihydrogen phosphate yielded the highest SBS values. Conclusions: Hot-etching with 9% HF gel in a safe shell formed uniformly small, defined holes on the zirconia surface and achieved significantly higher SBS values than sandblasting (p < 0.05). Zirconia prostheses can be bonded micromechanically with resin cement, without the deterioration of properties due to t-m transformation, using chemical acid etching with the Zirconia Etchant Cloud System.
... Adhesion with resin cement calls for surface preparation of restorative materials to provide stable and durable adhesive bonding (Stewart et al., 2002). Table 4 summarizes the available studies comparing the effect of different surface preparations on the bond strength of resin cements to different surfaces (Casucci et al., 2011;Chatterjee & Ghosh, 2022;D'Arcangelo et al., 2009;Duarte et al., 2008;Hitz et al., 2012;Murthy et al., 2014;Özdemir et al., 2019;Pisani-Proenca et al., 2006;Raeisosadat et al., 2020;Shimada, 2002;Turp et al., 2016;Upadhyaya et al., 2019). ...
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Objective: The aim of this study was to review the selection criteria of resin cements for different types of partial coverage restorations (PCRs) and investigate if the type of restorations or restorative materials affect the type of selected resin cement. Materials and methods: An electronic search (1991-2023) was performed in PubMed, Medline, Scopus, and Google Scholar databases by combinations of related keywords. Results: A total of 68 articles were included to review the selection criteria based on the advantages, disadvantages, indications, and performance of resin cements for different types of PCRs. Conclusions: The survival and success of PCRs are largely affected by appropriate cement selection. Self-curing and dual-curing resin cements have been recommended for the cementation of metallic PCRs. The PCRs fabricated from thin, translucent, and low-strength ceramics could be adhesively bonded by light-cure conventional resin cements. Self-etching and self-adhesive cements, especially dual-cure types, are not generally indicated for laminate veneers.
... Therefore, gritblasting has been used prior to the thermal treatment of (pre-sintered) zirconia to avoid the presence of microcracks. Also, selective infiltration etching has been carried out over pre-sintered zirconia (Aboushelib et al., 2007(Aboushelib et al., , 2009Casucci et al., 2011) after grit-blasting or machining. Apart from traditional physical and chemical approaches, other novel strategies need further investigation for establishing their impact on mechanical properties. ...
Surface modification of yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) using lasers for adhesion enhancement with resin-matrix cement has been increasingly explored. However, Y-TZP is chemically inert and non-reactive, demanding surface modification using alternative approaches to enhance its bond strength to resin-matrix cements. The main aim of this study was to conduct an integrative review on the influence of ultrashort pulse laser patterning of zirconia (3Y-TZP) for enhanced bonding to resin-matrix cements. An electronic search was performed on web of science, SCOPUS, Pubmed/Medline, Google Scholar and EMBASE using a combination of the following search items: zirconia, 3Y-TZP, surface modification, laser surface treatment, AND laser, ultrashortpulse laser, bonding, adhesion, and resin cement. Articles published in the English language, up to January 2022, were included regarding the influence of surface patterning on bond strength of Y-TZP to resin-matrix cements. Out of the 12 studies selected for the present review 10 studies assessed femtosecond lasers while 2 studies assessed picosecond lasers. Ultrashort pulsed laser surface patterning successfully produced different surface morphological aspects without damaging the bulk properties of zirconia. Contrarily, defects such as micro-cracks occurs after surface modification using traditional methods such as grit-blasting or long-pulsed laser patterning. Ultrashort pulsed laser surface patterning increase bond strength of zirconia to resin-matrix cements and therefore such alternative physical method should be considered in dentistry. Also, surface defects were avoided using ultrashort pulsed laser surface patterning, which become the major advantage when compared with traditional physical methods or long pulse laser patterning.
... 3 In this invitro study, to standardize the specimens, ceramic blocks were bonded onto composite resin blocks instead of teeth substrate due to the heterogeneous microstructure of dentin and to avoid the anticipated greater source of variability of dental substrate compared to a manufactured material such as the composite blocks. 17 Success of all ceramic restorations is mainly dependent on achieving a reliable and durable bond at ceramic/resin interface. 18 The gold standard for surface treatment of feldspathic and lithium disilicate ceramics has been considered to be HF acid etching, followed by silane application. ...
... 4 While hydrofluoric acid etching followed by silane application has been used successfully for glass-based ceramic systems, 5 this method is not effective for yttria tetragonal zirconia polycrystalline (Y-TZP) ceramic systems due to this material's chemically stable structure and high crystalline content. 3,6,7 The most effective methods that are recommended to enhance the resin bond to zirconiabased restorations are physicochemical treatments, which include sandblasting with airborne aluminum oxide (Al 2 O 3 ) particle abrasion followed by the application of primers containing a phosphate ester monomer, such as 10-methacryloyloxydecyl dihydrogen phosphate (MDP), or the application of silane coupling agents following tribochemical silica coating. [8][9][10] These treatments provide the mechanical effect of roughening the Y-TZP surface and a chemical effect due to the use of ceramic primers or silane coupling agents. ...
Purpose: To evaluate the effects of nonthermal atmospheric plasma (NTAP) treatment, alone or combined with sandblasting and/or primer application, on the bonding of zirconia ceramics to resin cement. Materıals and Methods: A total of 420 discs of Y-TZP (2 x 15 x 12 mm) were prepared and randomly divided into 10 groups according to surface treatment, as follows: Z (control), SB (sandblasting), Pr (primer), SBPr (sandblasting + primer), P (NTAP), SBP (sandblasting + NTAP), PrP (primer + NTAP), SBPrP (sandblasting + primer + NTAP), PPr (NTAP + primer), and SBPPr (sandblasting + NTAP + primer). After surface treatments, the surface roughness values were evaluated using a profilometer, and the contact angle measurements were performed using a goniometer. Surface characterizations of the groups were analyzed using scanning electron microscopy and x-ray photoelectron spectroscopy analyses. Shear bond strength tests were performed after adhesive cementation in 20 specimens per group, with half (n = 10) subjected to thermocycling (5,000 cycles, 5°C to 55°C). The failure mode was recorded by examining each specimen using a stereomicroscope. One-way and two-way ANOVA followed by Student-Newman-Keuls test (α = .05) were used to analyze the data statistically. Results: Untreated zirconia surfaces (without sandblasting) were found to have a higher wettability and oxygen ratio after NTAP treatment. The clinical application order of NTAP is an important factor, and the best combination for bonding quality was NTAP treatment followed by primer application on untreated zirconia (group PPr), rather than on a sandblasted surface. Conclusıon: NTAP application may be a promising surface treatment method for adhesive cementation of zirconia ceramics as an alternative to sandblasting. To achieve strong adhesion, NTAP should be applied before primer aplication.
... Sandblasting of the zirconia surface can enhance micromechanical interlocking and wettability by increasing the irregularities as well as the roughness 21,22) , which is considered as an effective pretreatment before cementation to improve the bond strength 23,24) . Zirconia does not have a glassy phase; therefore, hydrofluoric acid etching or silanization is not recommended, and phosphoric acid etching should be avoided 4,25) . ...
... Therefore, the pores formed on the surface of zirconia in the HF group are denser than those in the HCl group. The dense pores facilitate the locking of more cured resin cement on the surface of zirconia and achieve a larger chemical reaction area (Casucci et al., 2011). Finally, with the help of both micromechanical interlock and chemical adhesion, the bonding effect is guaranteed. ...
Full-text available
Zirconia has occupied an increasingly important role in oral clinical applications in recent years. However, how to achieve the ideal bonding effect of zirconia is a significant problem that needs to be solved urgently in oral clinics. Hot etching treatment of zirconia is a hot spot of current research, but it is still unclear about the optimal acid solution and the effect of hot etching on the surface topography and bond strength of zirconia. This study evaluated the effect of hot etching with HF and HCl on the surface topography, roughness, crystalline phase, zirconia/resin cement interfacial evaluation and shear bond strength of zirconia. The results showed that the hot etching groups produced completely different topographical changes on the surface of zirconia than the sandblasting group. Obvious interfacial cracks were observed in the sandblasting group. The HF hot etching group achieved the highest roughness values (78.17 ± 4.94 nm) and the highest shear bond strength (25.09 ± 4.09 MPa). Compared with HCl, hot etching with HF could achieve more uniform and dense porous morphology, greater roughness and shear bond strength. Moreover, there were no prominent zirconia/resin cement interfacial cracks and crystal phase transformations on the surface of zirconia.
... Sandblasting of the zirconia surface can enhance micromechanical interlocking and wettability by increasing the irregularities as well as the roughness 21,22) , which is considered as an effective pretreatment before cementation to improve the bond strength 23,24) . Zirconia does not have a glassy phase; therefore, hydrofluoric acid etching or silanization is not recommended, and phosphoric acid etching should be avoided 4,25) . ...
This study aimed to evaluate the shear bond strength (SBS) of four bonding agents used to bond metal brackets to zirconia under different storage conditions. Four bonding agents were used [FLC: (Fuji ORTHO LC), XT: (TransbondTM XT), RUC-SBU: (Rely XTM Ultimate Clicker Adhesive Resin Cement+Single Bond Universal), and RUC-GBU: (Rely XTM Ultimate Clicker Adhesive Resin Cement+Gluma Bond Universal)] to bond two types of metal brackets (PT/3M) to zirconia surfaces, and they were stored in water at 37ºC for 24 h or thermocycling for 3,000 cycles. The SBS data of RUC-SBU and RUC-GBU using PT brackets were significantly higher than those of 3M brackets before and after thermocycling. It could be concluded that RUC-SBU and RUC-GBU could offer sufficient bond strength between metal brackets and zirconia for the short term compared with FLC and XT. The design of brackets can significantly affect the bond strength to zirconia.
The surface of zirconia was treated with hot-acid etching of different durations to improve its shear bond strength to resin. Zirconia discs were subjected to untreated, sand-blasting, and hot-etching treatments for 10, 30 and 60 min. The discs were bonded to the surface of bovine enamel specimens using RelyX Ultimate resin cement. The bonded specimens were divided into immediate and thermocyling aging groups according to whether they underwent thermal cycling. A universal mechanical testing machine was used to measure the shear bond strength of the specimens. One-way analysis of variance was used to determine the effect of hot-etching time on the shear bond strength. In the immediate and thermocyling aging groups, 60 min of hot-etching provided significantly higher shear bond strength than the other conditions (p<0.05).
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Objectives This study aimed to evaluate whether conditioning with hydrofluoric acid in higher elevations with a longer application time can promote an increase in surface roughness and shear bond strength to zirconia. Methods Fifty zirconia cylinders (Vipiblock- Zinconn- Vipi-Brazil) were made using CAD / CAM system and cemented with Panavia F 2.0 resin cement (Kuraray-Japan) in composite resin cylinders filtek Z-350 XT (3M / ESPE-EUA), after different surface treatments of zirconia (n = 10): Group 1 - No surface treatment; Group 2 - Conditioning with 40% hydrofluoric acid, for 2 minutes; Group 3 - Conditioning with 40% hydrofluoric acid, for 4 minutes, Group 4 - Conditioning with 50% hydrofluoric acid, for 2 minutes and Group 5 - Conditioning with 50% hydrofluoric acid, for 4 minutes. Right after cementation, all specimens were subjected tothermocycling (5000 cycles; 5º to 55ºC), storaged in distilled water at 37ºC for 730 days and subjected to the shear bond strength test in a universal testing machine until fracture. The F test (ANOVA) for one factor and the multiple comparison tests of Tamanhe were used (p < 0,05). Results The highest mean corresponded to group 3 (4.47 Mpa), followed by group 5 (4.05 Mpa), Group 4 (3.28 Mpa) and group 2 (3.14 Mpa). Significance Conditioning with 40% hydrofluoric acid for 4 minutes obtained the highest values of bond strength to zirconia, however there was no statistically significant difference in relation to the concentration of 50%, for 2 and 4 minutes.
Full-text available
To investigate the influence of chemical and enzymatic degradation on the stability of zirconia resin bond strength using micro-shear bond strength test. Zirconia discs were airborne particle abraded (SB) or selective infiltration etched (SIE) while no surface treatment served as control. Resin composite (Filtek Z250) microdiscs were bonded to zirconia using self-adhesive universal resin cement (RelyX UniCem). Micro-shear bond strength (microSBS) test was conducted after immersion in the following degrading media: 24 hours and 2 weeks of water storage, and 2 weeks in NaOH, alcohol, or esterase enzyme (n=10). There was a significant influence of the surface finish (P < 0.001, F=154.5), biodegradation medium (P < 0.001, F=52.9), and their interaction (P < 0.001, F=6.0) on zirconia resin bond strength. In general SIE group revealed the highest microSBS values (8.1 - 34.5 MPa) after degradation in different media, followed by SB group (8.7 - 28.5 MPa), while the control group showed significantly lower bond strength (0.4 - 9 MPa).
Conference Paper
High-strength all-ceramic systems for fixed partial dentures (FPDs) are available for replacing a missing tooth. New core/framework materials have been developed and have evolved in the last decade. With the advancement of CAD/CAM technology, various fabrication techniques have been developed for fabricating improved, consistent, and predictable restorations in terms of strength, marginal fit, and esthetics and for managing core/framework materials that could not otherwise be managed. This article reviews the evolution and development of materials and technologies for all-ceramic FPDs through data published between 1966 and 2004 in the English language. Peer-reviewed articles were identified through a MEDLINE search and a hand search of relevant textbooks and annual publications. The available information suggests that clinical data on the success of these restorations are limited, and that the results of long-term clinical studies are critical to the assessment of these restorations to provide more specific guidelines for usage.
Selective infiltration etching (SIE) is a newly developed surface treatment used to modify the surface of zirconia-based materials, rendering them ready for bonding to resin cements. The aim of this study was to evaluate the zirconia/resin bond strength and durability using the proposed technique. Fifty-four zirconia discs were fabricated and divided into three groups (n = 18) according to their surface treatment: as-sintered surface (control group), airborne-particle abrasion (50-mum aluminum oxide), and SIE group. The zirconia discs were bonded to preaged composite resin discs using a light-polymerized adhesive resin (Panavia F 2.0). The zirconia/resin bond strength was evaluated using microtensile bond strength test (MTBS), and the test was repeated after each of the following intervals of accelerated artificial aging (AA): thermocycling (10,000 cycles between 5 and 55 degrees C), 4 weeks of water storage (37 degrees C), and finally 26 weeks of water storage (37 degrees C). Silver nitrate nanoleakage analysis was used to assess the quality of zirconia/resin interface. A repeated measures ANOVA and Bonferroni post hoc test were used to analyze the data (n = 18, alpha= 0.05) There were significant differences in the MTBS values between the three test groups at each of the test intervals (p < 0.001). AA resulted in reduction in the bond strength of the as-sintered and the particle-abraded groups (5.9 MPa and 27.4, MPa, respectively). Reduction in the bond strength of these groups was explained by the observed nanoleakage across the zirconia/resin interface. The bond strength of the SIE specimens was stable after completion of AA (51.9 MPa), which also demonstrated a good seal against silver nitrate penetration across the zirconia/resin interface. SIE established a strong, stable, and durable bond to zirconia substrates. Conservative resin-bonded zirconia restorations are now possible using this new technique.
The popularity of high-strength ceramic systems is increasing, and the range of their clinical indications is expanding constantly. Glass-infiltrated aluminum oxide ceramic (eg, InCeram® Alumina, Vita Zahnfabrik, Bad Säckingen, Germany), densely sintered aluminum oxide ceramic (eg, Procera® AllCeram, Nobel Biocare AB, Gothenburg, Sweden), and zirconium oxide ceramic (eg, Procera AllZirkon®, Lava® 3M ESPE, St. Paul, MN, USA, Cercon®, Dentsply Ceramco, Burlington, NJ, USA) are popular oxide-based high-strength ceramic materials that offer favorable esthetic characteristics, mechanical properties, and biocompatibility. Proper selection and application of luting agents for final cementation of all-ceramic restorations are keys for their clinical success. The few clinical trials on full-coverage, high-strength ceramic restorations report acceptable success rates with conventional luting agents. However, an article discussed in Part I of this Critical Appraisal reviewed available in vitro and in vivo studies on this topic and recommended adhesive cementation of ceramic and even high-strength ceramic restorations. These findings contradict many manufacturers’claims and clinicians’preferences because resin bonding is a technique-sensitive and time-consuming procedure. However, resin bonding has a number of advantages (eg, increased retention, improved marginal adaptation, and higher fracture resistance of the restored tooth and the restoration itself) and is required for some minimally invasive treatment options, such as resin-bonded fixed partial dentures and laminate veneers.
Purpose: To compare the flexural strength of two glass-infiltrated high-strength ceramics and two veneering glass-ceramics. Materials and methods: Four ceramic materials were tested: two glass-infiltrated high-strength ceramics used as framework in metal-free restorations [In-Ceram Zirconia IZ (Gr1) and In-Ceram Alumina IA (Gr2)], and two glass-ceramics used as veneering material in metal-free restorations [Vita VM7 (Gr3) and Vitadur-alpha (Gr4)]. Bar specimens (25 x 5 x 2 mm3) made from core ceramics, alumina, and zirconia/alumina composites were prepared and applied to a silicone mold, which rested on a base from a gypsum die material. The IZ and IA specimens were partially sintered in an In-Ceram furnace according to the firing cycle of each material, and then were infiltrated with a low-viscosity glass to yield bar specimens of high density and strength. The Vita VM7 and Vitadur-alpha specimens were made from veneering materials, by vibration of slurry porcelain powder and condensation into a two-part brass Teflon matrix (25 x 5 x 2 mm3). Excess water was removed with absorbent paper. The veneering ceramic specimens were then removed from the matrix and were fired as recommended by the manufacturer. Another ceramic application and sintering were performed to compensate the contraction of the feldspar ceramic. The bar specimens were then tested in a three-point bending test. Results: The core materials (Gr1: 436.1 +/- 54.8; Gr2: 419.4 +/- 83.8) presented significantly higher flexural strength (MPa) than the veneer ceramics (Gr3: 63.5 +/- 9.9; Gr4: 57.8 +/- 12.7). Conclusion: In-Ceram Alumina and Zirconia were similar statistically and more resistant than VM7 and Vitadur-alpha.
The effect of surface treatment using tribochemical silica coating/silane coupling on the shear bond strengths of (1) a glass-infiltrated, zirconia-reinforced alumina (In-Ceram Zirconia) and (2) a yttria-stabilized zirconia ceramic (YZ Zirconia) to human dentin was studied. Twelve specimens of each ceramic were randomly assigned to one of three surface treatments: (1) no surface treatment (control group); (2) a chairside tribochemical silica coating/silane coupling system (CoJet group); and (3) a laboratory tribochemical silica coating/silane coupling system (Rocatac group). The mode of failure of each specimen was determined under magnification. The shear bond strengths (mean ± SD) of In-Ceram Zirconia of the control, CoJet and Rocatec groups were 5.7 ± 4.3 MPa, 11.4 ± 5.4 MPa, and 6.5 ± 4.8 MPa, respectively. The corresponding figures for YZ Zirconia were 8.2 ± 5.4 MPa, 9.8 ± 5.4 MPa, and 7.8 ± 4.7 MPa. Two-way ANOVA revealed significant differences in bond strength due to the difference in surface treatment (p= 0.02), but the bond strengths between the two ceramics were not significantly different (p= 0.56). Post hoc tests showed that In-Ceram Zirconia treated with CoJet had significantly higher shear bond strengths than those untreated (p < 0.05) or treated with Rocatec (p < 0.05). Surface treatment did not affect the shear bond strength of YZ Zirconia significantly (p > 0.05). The bonding of In-Ceram Zirconia can be improved by the chairside surface treatment system.
Ceramics have a long history in fixed prosthodontics of achieving optimal esthetics. Yttrium tetragonal zirconia polycrystal (Y-TZP)-based systems are a recent addition to the high-strength, all-ceramic systems used for crowns and fixed partial dentures. CAD/CAM-produced, Y-TZP-based systems are in considerable demand in esthetic and stress-bearing regions. The highly esthetic nature of zirconia coupled with its superior physical properties and biocompatibility have resulted in restorative systems that meet the demands of today's patients. Undoubtedly, these systems are considered to be prospective replacements for metal-ceramic restorations. This article reviews relevant contemporary literature regarding all-ceramic materials and systems and discusses their material properties, biocompatibility, advances in cementation, and more with special emphasis on clinical survival. The article also aims to provide recommendations for their use.
This report presents a novel pretreatment technique, whereby the zirconia surface is converted to a more reactive zirconium oxyfluoride, enabling improved chemical bonding to other dental substrates via conventional silanation approaches. The study leverages a novel gas-phase fluorination process that creates a thin oxyfluoride conversion layer on the surface of zirconia, making it more reactive for conventional adhesive bonding techniques. Zirconia specimens, polished and roughened, were pretreated and composite cylinders bonded using conventional adhesive techniques. All specimens were subjected to a force at a crosshead speed of 0.5mm/min in an electro-mechanical testing device. Single-factor analysis of variance (ANOVA) at a 5% confidence level was performed for the bonding strength data. Optical microscopy and scanning electron microscopy (SEM) were used to evaluate and quantify failure surfaces. Shear bond strengths were analyzed using single-factor ANOVA (p<0.05). Mechanical testing results revealed that fluorinated zirconia specimens (both rough and polished) displayed the highest shear bond strengths as compared to other commercially available treatments. X-ray photoelectron spectroscopy analysis helped determine that this novel pretreatment created a more reactive, 2-4nm thick oxyfluoride conversion layer with approximate stoichiometry, ZrO(3)F(4). Simple shear bond mechanical tests demonstrated that a fluorination pre-treatment is a viable method to chemically modify zirconia to produce a reactive surface for adhesive bonding.