Adriana Pirte

Cosmin Sinescu

Emanuela Petrescu

Florin I Topala

Laura-Cristina Rusu

Lavinia Ardelean

Meda Lavinia Negrutiu

Mihai Fabricky

Mihai Rominu

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REV. CHIM. (Bucharest) ♦ 63♦ No. 6 ♦ 2012http://www.revistadechimie.ro584
AFM Analysis of Conditioned IPS Empress Ceramic Core
EMANUELA PETRESCU1, MIHAI ROMINU1, MEDA LAVINIA NEGRUTIU1*, COSMIN SINESCU1, MIHAI FABRICKY1,
LAVINIA ARDELEAN1, LAURA-CRISTINA RUSU1, FLORIN I.TOPALA1, ADRIANA PIRTE2
1 University of Medicine and Pharmacy “Victor Babes” Timisoara,  Faculty of Dentistry, 9 Revolutiei, Blv., 300070,
Timisoara, Romania
2 University of Oradea, Department of Dentistry, 10, 1 Decembrie Str., 410068, Oradea, Romania
The purpose of this study is to investigate the conditioned ceramic core of IPS Empress systems. Due to
brittle character of all ceramic materials, fracture may occur. This accident may be rehabilitated through
conditioning and reparations of the prosthetic restaurations. Fracture of ceramic veneer may be reconstructed
with either ceramic or composite resin materials. Acid conditioning and sandblasting may improve adhesion
to ceramic core. One of the methods which may evidence the aspect of the conditioned surface is Force
Atomic Microscopy. Depending by the conditioning method, different maps of the conditioned ceramic cores
are obtained and conditioning protocol may be evaluated and reconmanded for practical use.
Keywords: ceramic core, ceramic veneer, conditioning methods, Force Atomic Microscopy
* email:  meda_negrutiu@yahoo.com
All ceramic materials brought many changes in dentistry
and are finding their applycability in prosthetics- venners,
inlays, onlays, all ceramic crowns, fixed partial prosthesys-
implantology- dental implants. Othodontics is another
branch witch takes benefits form these materials. Their
excellent properties makes them very attractive for fixed
partial restorations, especially when restoring the teeth from
frontal area.
There are a few methods or systems to make all the
ceramic restorations, but in this study  IPS Empress e.max
is the one involved.
All-ceramic fixed partial prosthesis are the best choice
for excellent aesthetics. Patients have high expectations
about quality and aesthetics and longevity of the dental
prosthesis. All ceramic fixed systems appeared more than
three decades ago and along this time, they  were
constantly improved and developed.
 At present all-ceramic systems may replace metal-
ceramic fixed partial prosthesis. All-ceramic inlays, onlays,
veneers and crowns can restore teeth with extended
destructions and which must be conserved and may also
assure the integrity of partial edentulous arches. New
ceramic systems are now reinforced through dispersion
with leucite, glass infiltration into sintered alumina (Al 2O3),
high-purity alumina or zirconium dioxide (Zirconia, ZrO2). .
All ceramic fixed partial prosthesis may be performed
through different techniques, such as heat pressed ceramic
IPS Empress, grinding of ceramic blocs IPS Empress
crowns are made from a ceramic core obtained from
plasticized ceramic and burned ceramic layers. These
types of prosthesis put out the metallic infrastructure which
bright at the cervical area when marginal retraction of the
gums  takes place or the ceramic layers in third cervical is
too thin.  Tattoo of the cervical gum is another inconvenient
which affects the aesthetic aspect. Despite of its qualities
metallic infrastructure is replaced by ceramic core made
through heat pressing or grinding procedure. Ceramic layers
are layered and burned over the ceramic core. All ceramic
fixed partial prosthesis has a few sensitive properties. One
of them is the fracture of ceramic veneer or ceramic core.
It takes place because ceramic masses have no elasticity
and have a brittle character. Occlusal overloading, defects
into the ceramic mass which appear during technological
process, fissure which may generate the fracture of the
ceramic veneer and cement wash in case of an incorrect
marginal adaptation which lead to absence of stability and
adhesion of the all ceramic crowns. These are a few
reasons for which an all ceramic crowns can fail.
Experimental part
Materials and methods
The demand for all ceramic systems is increasing.  For
this study 15 all ceramic crowns were made through heat
pressing technique. All the crwons restore the upper first
incisor and were made through IPS Empress. e.max
sustem. Though the aesthetic aspect of the restoration was
ot the purpose of this study, all the setps and morphological
aspects were made. Unusally due to brittle character of
ceramic masses the fracture of ceramic component is
located in the third incise or third cervical area. These two
areas are suusceptible to fracture because the ceramic is
not plain layed and the layers are thinner and the resistance
is compromised. These fractures may be rehabilitated
through direct methods with composite resin. When
conditioning the ceramic core the adhesion composite
resin used for reparation may be improved through diferent
methods.
 Ceramic mass from third incise of buccal face of each
crown was removed in order to reproduce the situation of
a fractured ceramic crowns repaired through direct method
with composite resin.The ceramic was removed with a
grinding instrument, without pressure for avoiding other
additional fisures or craks.  Ceramic core was exposed
and conditioned. Samples were divided into three groups.
The ceramic cores of first group were sandblasted with
Al2O3 at a pressure of 3 Bar from a distance of 10mm. The
second group was etched with HF 9% for 90s. Ceramic
cores of the third group were grinded with a diamonded
instrument and etched with HF 9% for 90 s.
All the samples were investigated by Atomic Force
Microscopy which may spot the differences of the ceramic
surface conditioned through different methods. The
extremelly sensitive cantilever (5μm height and 10 nm
diameter) is scanning the conditioned ceramic surface.
Interaction forces between the tip and samples surface
determine the bending of the cantilever. A sensitive detector
measures the cantilevers deformations while the tip is
scanning the sample. The recived signal is transmited to a
computer which will map the sanded surface. Positive and
negative reliefs are obtained.
REV. CHIM. (Bucharest) ♦ 63 ♦ No. 6 ♦ 2012 http://www.revistadechimie.ro 585
Fig. 6. Volume islands 2 micro
Fig. 1. Acid conditioning HF 9% of ceramic core
Fig.2 Volme of islands 546nm
Fig. 3. Grinding and acid conditionig HF 9% of ceramic core
Fig.4.  Volme of islands 1micro
Fig.5. Sandblasted ceramic core
Depending by the conditioning methods, different
aspects of the surface were obtained.All the samples were
investigated by Force Atomic Microscopy and the results
give the posibility to indicate the proper method for
conditioning the ceramic core.
Results and discussions
Atomic force microscophy is proved as a usefull tool for
the nondistructive imagistic evaluation method. Obtaining
the real surface profile for the ceramic suport is important
for the quality of the future ceramic veneering. It could
give information about the right material that it is proper
for that infrastructure, esspecialy when repairing methods
are employed.
Each conditioning protocol developed a different surface
relief. Though similar, the orientation and the deep of the
gaps, lines and craters are various. The group conditioned
by grindin emphasised a more aggresive relief
characterized as deep lines. But combining the imagies
with the obtained resuts the most signifiant roughness is
the acid conditioning and sandblasting gives a much planne
relief not favourable for surface roughness. The micro
retentivies may influence the surface in a positive way.
The Atomic force microscophy tools could be use in
order to obtain quatitative results (fig. 2, 4, 6). In this way a
statistic analisys can be produced and the resuls could
validate the imagistic qalitative results. In this way the total
surface and the deeper dimensions of the new profile
obtained after different conditionig methods can be pointed
out.
Conclusions
After applying the described conditioning methods the
retentive microrelief is depending on the conditioning
method. Further investigations will test the shear bond
strength resulted after applying this conditioning protocols.
Acknowledgment: I would like to acknowledge for the support of
CNCSIS Research Project For Young Team 101/2010.
REV. CHIM. (Bucharest) ♦ 63♦ No. 6 ♦ 2012http://www.revistadechimie.ro586
References
1.ROMINU, R. O., ROMINU, M., NEGRUTIU, M., SINECU, C., POP, D.M.,
PETRESCU, E., Adeziunea Amelara- Curs pentru studentii Facultatii
de Medicina Dentara 2011
2. LOYOLA-RODRIGUEZ JP, ZAVALA-ALONSO V, REYES-VELA E.,
PATINO-MARIN N, RUIZ F, ANUSAVICE K- Atomic force microscopy
observation of the enamel depth profile after phosphoric acid etching.
Journal of Electron Microscopy 59 (2): 119-125, 2010
3. HABELITZ S, BALOOCH M, MARSHALL GW, BREUNIG TM, MARSHALL
SJ- AFM-based nano-mechanical properties and storage of dentin and
enamel. Mat Res Soc Symp Proc 676, 2001
4.  NELSON E, BARGHI N – Effect of APF etching on resin bonded
porcelain, J Dent Res 68:271, 1989
Manuscript received: 7.12.2011


AFM Analysis of Conditioned IPS Empress Ceramic Core

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AFM Analysis of Conditioned IPS Empress Ceramic Core

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