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This study evaluates the marginal adaptation of ceramic copings (In-Ceram, Vita) front of two finish lines and internal surface treatment (Rocatec, ESPE). For this, two master steel dies were milled with all-ceramic crowns preparation, one with a round shoulder (RS) margin design, and the other with a deep chamfer (DC). Twenty copings were made, and the marginal discrepancy was evaluated in measuring microscope, obtaining an initial measure. Each group was divided in two others, which received two kinds of silica sandblasting: (1) in all inner crown surface - DCt and RSt - and (2) in the inner crown surface, but preserving the cervical edge - DCa and RSa. The discrepancies were measured again and the data submitted to the statistical analysis. Marginal discrepancy values of 42,37±18,78μm were observed for group DC and 33,35±20,08μm for group RS in the initial measures, without significant statistical differences among them. The initial and final gap values were compared to each one of the experimental groups, being observed statistical differences in DCa and DCt. Statistical differences was not observed among the post-sandblasting values. It was concluded that both cervical endings present similar marginal adaptations between them when not submitted to any treatment type. When accomplished the surface treatment, negative influence was observed in the marginal adaptation of some groups, if compared the initial and final values, in spite of differences among the last ones were not been observed.
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9Cienc Odontol Bras 2003 out./dez.; 6 (4): 9-16
INTRODUCTION
Nowadays, the esthetic lives a great moment in
the history of Dentistry, as much for the develop-
ment of new materials as for the own inherent es-
thetic appeals to the modern society. Besides, the
* Master’s Dissertation Summary – SJCampos – UNESP, São Paulo, Brazil
Evaluation of the marginal adaptation of ceramic copings in function of the
cervical endings and treatment of the internal surfaces*
Avaliação da adaptação marginal de copings cerâmicos em função do término
cervical e tratamento das superfícies internas
Edson HILGERT, MDS
Postgraduate student – Resthorative Dentistry Program – Prosthesis – Dental School of Dentistry of São José dos
Campos – UNESP, São Paulo, Brazil
Maximiliano Piero NEISSER, PhD
Professor – Department of Dental Materials and Prosthodontics – Dental School of Dentistry of São José dos
Campos – UNESP, São Paulo, Brazil
Marco Antonio BOTTINO, PhD
Professor – Department of Dental Materials and Prosthodontics – Dental School of Dentistry of São José dos
Campos – UNESP, São Paulo, Brazil
ABSTRACT
This study evaluates the marginal adaptation of ceramic copings (In-Ceram, Vita) front of two finish lines and
internal surface treatment (Rocatec, ESPE). For this, two master steel dies were milled with all-ceramic crowns
preparation, one with a round shoulder (RS) margin design, and the other with a deep chamfer (DC). Twenty
copings were made, and the marginal discrepancy was evaluated in measuring microscope, obtaining an initial
measure. Each group was divided in two others, which received two kinds of silica sandblasting: (1) in all inner
crown surface - DCt and RSt - and (2) in the inner crown surface, but preserving the cervical edge - DCa and
RSa. The discrepancies were measured again and the data submitted to the statistical analysis. Marginal discre-
pancy values of 42,37
±
18,78
µ
m were observed for group DC and 33,35
±
20,08
µ
m for group RS in the initial
measures, without significant statistical differences among them. The initial and final gap values were compared
to each one of the experimental groups, being observed statistical differences in DCa and DCt. Statistical diffe-
rences was not observed among the post-sandblasting values. It was concluded that both cervical endings pre-
sent similar marginal adaptations between them when not submitted to any treatment type. When accomplished
the surface treatment, negative influence was observed in the marginal adaptation of some groups, if compared
the initial and final values, in spite of differences among the last ones were not been observed.
UNITERMS
Ceramics, surface treatment, marginal adaptation, finish lines
discussion related to the biocompatibility of den-
tal alloys becomes more and more constant. That
turns the use of metal free prostheses a tendency
of the modern dentistry, due to its low toxicity and
allergic potential, besides the excellent aesthetic
properties (CHRISTENSEN
6
, 1999).
10
Hilgert E, Neisser MP, Bottino MA
EVALUATION OF THE MARGINAL ADAPTATION OF CERAMIC COPINGS IN FUNCTION OF THE CERVICAL ENDINGS AND TREATMENT OF THE
INTERNAL SURFACES
Cienc Odontol Bras 2003 out./dez.; 6 (4): 9-16
This way, the development metal free prosthe-
ses came in a fast way, its source being the first
porcelain jacket crowns, going through modifica-
tions as the addition of alumina content, announ-
ced firstly by McLean & Hughes
19
in 1965, coming
into several ceramic systems with high flexural re-
sistance and quite a lot of indications. One of the
most versatile systems is named In-Ceram (Vita
Zahnfabrik), created by Sadoun in 1986 (GROTEN
et al.
7
, 1997), who uses alumina or zirconia cera-
mic. In In-Ceram Alumina, particles of alumina
with fine granulation are joined to form a porous
sub-structure and lately infiltrated by liquefied
glass. The association between these two proces-
ses confers to the material its outstanding proper-
ties. In the sinterization process, the contraction is
almost inexistent, providing an excellent adaptati-
on, while the glass infiltration practically does not
leave porosities, resulting in high resistance of the
material (KERN et al.
14
, 1991; PRÖBSTER & DI-
EHl
23
, 1992; PERA et al.
22
1994).
With the innovations in restorative systems,
the union agents also increased in order to pro-
mote appropriate adhesion of these materials to
the dental structures. In the In-Ceram case speci-
fically, the acid etching and silanization did not
achieve good results related to the union with re-
sins BIS-GMA, due to the high alumina content
and lower silica content (KERN & THOMPSON
11
,
1994). Because of that, the use of conventional
cements or phosphate monomer based ones has
been introduced when an adhesive luting is desi-
re (KERN & THOMPSON
13
, 1995; MADANI
16
,
2000).
Thus, ways to make these materials compati-
ble were researched, and a found alternative was
to raise the superficial content of silica of the alu-
minized structures across a tribochemical process,
by using a developed system for metallic structu-
res. This system, named Rocatec (ESPE), consists
of two sandblasting stages procedure, being the first
a pre-treatment with alumina powder (Rocatec Pre),
followed by the second sandblasting with particles
of the silica base (Rocatec Plus or Rocatec Soft).
The use of Rocatec has been extrapolated, with
good results, to the high density alumina structu-
res, providing a better likeness of this to the sila-
ne, due to the greater superficial concentration of
silica given to these structures by the sandblasting
(KERN & THOMPSON
13
, 1995; KOURTIS
15
,
1997).
With the sandblasting, superficial modificati-
ons as the inclusion of the silica particles and su-
perficial abrasion can cause variations in the sea-
ting of the prosthetic crown and in the marginal
fidelity. Kern & Thompson
12
(1994) comment that
the sandblasting of ceramic restorations has the
potential of removing significant amounts of ma-
terial and to affect the clinical adaptation of the
restoration. The importance given in literature for
the marginal adaptation makes the investigation of
these variations necessary and if they are clinically
significant; also, to verify the best configurations
of finish lines of dental preparations for ceramic
crowns, once the cement line of fixed and unitary
partial prostheses is still a critical point in the pros-
thetic treatment.
This way, the aim of this study was to evaluate
the marginal adaptation of aluminized ceramic co-
pings infiltrated by glass, attesting the influence
of the finish lines configuration and the possibility
of changes in the marginal adaptation of them by
using a silica sandblasting method (Rocatec,
ESPE), varying the application method.
MATERIAL AND METHODS
Two metallic dies were milled in stainless ste-
el, which served as master models (BOTTINO
3
,
1998), simulating prepares for metal free total cro-
wns, with mean dimensions of a second inferior
molar, differing only in the type of finish line (Fi-
gure 1). The finish lines used were the round shoul-
der (RS) and deep chamfer (DC), extolled in the
literature for making metal free prostheses
(PRÖBSTER & DIEHL
23
, 1992; SHEARER et al.
25
,
1996). In the cervical margin a semicircular notch
was done in a way to permit the replacement of the
ceramic copings for the readings accomplishment.
From these metallic dies, plaster replicas were
obtained on which the copings would be made. For
the reproduction of the metallic die, moldings were
accomplished with addition silicone (Elite H-D
Putty Soft - Normal Setting and Regular Body -
Normal Setting, Zhermack, Italy) by the double
impression technique. The standardization of the
insert and removal axis during the procedure were
achieve with an adapted dental surveyor, where in
your movable vertical rod a thread was made, that
allowed the fixation of the metallic die. In its base
was an attachment that allowed the positioning of
the centralized tray to the vertical rod’s axis. The-
11
Hilgert E, Neisser MP, Bottino MA
EVALUATION OF THE MARGINAL ADAPTATION OF CERAMIC COPINGS IN FUNCTION OF THE CERVICAL ENDINGS AND TREATMENT OF THE
INTERNAL SURFACES
Cienc Odontol Bras 2003 out./dez.; 6 (4): 9-16
se trays were made in steel, with a cylindrical de-
sign and perforations for the impression material
retention. The manipulation procedures of the im-
pression material and the plaster pouring were ac-
complished according to the manufacturers’ recom-
mendations. The impressions and the plaster dies
(Durone, Dentsply) were analyzed related to the
presence of bubbles or imperfections and if detec-
ted, the procedure was repeated. For each prepare,
twenty impressions were accomplished, resulting
in forty moulds and models.
After the attainment of all the plaster dies, the
In-Ceram system spacing was applied on them, then
duplicated in a special plaster, with aid of addition
silicon. From these dies, the copings were made
according to the protocol established by the manu-
facturer.
This way, the initial measurements were accom-
plished (L
0
). Firstly, the metallic die was fixed on
an octagonal base that served as orientation of the
marginal discrepancy measuring points. The coping
was positioned on the metallic die and blocked in
position with the aid of a gadget developed by Pa-
vanelli et al.
21
(2001). This provided constant pres-
sure during the whole measurement process throu-
gh a piston fixed by lateral screws (Figure 2).
The measurements were accomplished accor-
ding to the definition of marginal gap by Holmes
et al.
8
(1989), in a measuring microscope (Olym-
pus Microscope Precision STM, Japan), with digi-
tal table, 30X of magnification and 0,5mm precisi-
on. The readings were done three times in each
measurement point, achieving a mean, being that
four opposite points diametrically were read in each
coping, originating 12 gap measurements for each
sample.
After the initial reading of the first two groups
(DC and RS), each one of these was divided in
other two subsets groups (n=10), according to the
silica coating application: total application (DCt
and RSt) or with relief in the border (DCa and
RSa) (Picture 1). In the groups with total applica-
tion, the alumina oxide sandblasting was applied
in the whole internal surface of the crown and
cervical ending and, after cleaning with compres-
sed air, the silica sandblasting (Rocatec Plus,
ESPE), with pressure of 2,5bar; distance of 10mm
and time of application of 14seg (KERN &
THOMPSON
13
, 1995). In the groups in that the
application with relief, previously to the surface
treatment, the cervical border of the coping was
alleviated in approximately 1mm with inlay wax
in its entire circumference, to avoid the contact
of the sandblasting with this area. With the sand-
blasted copings, the measurements marginal gap
values was proceeded again, (L
1
) for the four tre-
ated groups, with the same procedures and crite-
ria used in the previous measurements.
FIGURE 1 – Schematic drawing of the master dies.
12
Hilgert E, Neisser MP, Bottino MA
EVALUATION OF THE MARGINAL ADAPTATION OF CERAMIC COPINGS IN FUNCTION OF THE CERVICAL ENDINGS AND TREATMENT OF THE
INTERNAL SURFACES
Cienc Odontol Bras 2003 out./dez.; 6 (4): 9-16
The data acquired with the L
0
measurements
were submitted to the statistical analysis in order
to verify statistical differences among the finish li-
nes, using the Student’s t-test. The values of L
0
and
L
1
were also compared with the t-test in each expe-
rimental group in order to verify the influence of
the treatment with Rocatec in its marginal gap. The
analysis among the groups after they’ve received
the treatment of the internal surfaces (L
1
) was ac-
complished with the analysis of variance test (ANO-
VA). All the tests were accomplished with the aid
of the software Statistix for Windows 7.0 (Analyti-
cal Software Inc.) with significance level of 5%.
RESULTS
Mean marginal discrepancy values were obser-
ved (L
0
) of 42,37µm for Deep Chamfer and
33,35µm for the Round Shoulder (Table 1 and Fi-
gure 3). These averages were submitted to the sta-
tistical analysis with the Student’s t-test, with a sig-
nificance level of 5%, not being observed
significant statistical differences among the finish
lines.
The L
0
and L
1
valueswere compared in each one
of the experimental groups with the Student’s t-
test. Significant statistical differences were obser-
ved in the groups DCa and DCt. In the group RSt
statistical differences were not observed, with le-
vel of significance of 5%, but it presented extre-
mely close values at this level (p=0,055) (Table 2
and Figure 4).
Two criteria analysis of variance test (ANOVA)
were accomplished to compare the obtained valu-
FIGURE 2 – Gadget developed to blocking the coping on the mas-
ter die: (P) fixing screw; (E) piston; (B) base.
es of L
1
, not being observed difference statistics
among the groups (p=0,05).
Discussion
The use of metal free prostheses permits a gre-
at opening of applications inside of the modern
Dentistry, due to its biocompatibility and capacity
to reproduce, in a clinical condition, extremely ple-
asant esthetic aspects in the oral rehabilitation
(CHRISTENSEN
6
, 1999). But the success of any
restorative procedure in Dentistry is intimately
linked to the precision of adaptation of the substi-
tute material to the tooth. This way, the evaluation
of the ceramic crowns marginal adaptation is ab-
solutely important for the scientific proof of clini-
cal situations.
This work evaluated the marginal adaptation of
In-Ceram copings instead of concluded crowns,
therefore some works in literature affirm that the
Picture 1 - Division of the experimental groups in function of the finish lines and of the surface treatment
it interns with application of Rocatec
Groups n Rocatec application
Finish Line FL/Application
Deep Chamfer (DC) DCa 10 preserving the borders of crowns
DCt 10 total application
Round Shoulder (RS) RSa 10 preserving the borders of crowns
RSt 10 total application
13
Hilgert E, Neisser MP, Bottino MA
EVALUATION OF THE MARGINAL ADAPTATION OF CERAMIC COPINGS IN FUNCTION OF THE CERVICAL ENDINGS AND TREATMENT OF THE
INTERNAL SURFACES
Cienc Odontol Bras 2003 out./dez.; 6 (4): 9-16
Table 1 - Descriptive statistics of the measuring data of L
0
- Deep Chamfer x Round Shoulder (µm)
n=20 L
0
Deep Chamfer DC = 42,37±18,78 A
Round Shoulder RS = 33,35±20,08 A
Averages followed by the same letter in the column do not differ one from the other at 5% level of significance.
Table 2 – Descriptive statistics of the measuring data of L
0
and L
1
depending on finish lines and surface
treatment
n=10 L
0
L
1
Deep Chamfer DCa 36,87 (±16,42) 46,62 (±21,27) A
DCt 47,87 (±20,19) 52,65 (±19,61) A
Round Shoulder RSa 38,48 (±21,53) 35,02 (±25,12) A
RSt 28,20 (±18,20) 39,50 (±32,30) A
Averages followed by the same letter in the column do not differ one from the other at 5% level of significance
FIGURE 3 – Graphic presentation of marginal gap averages for the initial measurements (L
0
).
FIGURE 4 – Graphic presentation of marginal gap averages for the initial and final measurements.
14
Hilgert E, Neisser MP, Bottino MA
EVALUATION OF THE MARGINAL ADAPTATION OF CERAMIC COPINGS IN FUNCTION OF THE CERVICAL ENDINGS AND TREATMENT OF THE
INTERNAL SURFACES
Cienc Odontol Bras 2003 out./dez.; 6 (4): 9-16
marginal modification in In-Ceram, due to the se-
veral covering ceramic firing cycles, is not consi-
dered significant (PERA et al.
22
, 1994; SHEARER
et al.
25
, 1996; GROTEN et al.
7
, 1997; SULAIMAN
et al.
27
, 1997). Two types of finish lines were used,
deep chamfer and the round shoulder, because they
are the most recommended in the literature
(PRÖBSTER & DIEHL
23
, 1992; SHEARER et al.
25
,
1996) for the confection of metal free crowns. This
is due to its horizontal configuration, once the be-
vel is contraindicated in this prosthesis type, be-
cause thin margins tend to fracture with easiness
in ceramic restorations.
Two metallic master models, in substitution to
natural teeth, were used in this study and on them
accomplished the tests. Beschnidt & Strub
1
(1999)
report that natural teeth present great variation con-
sidering the age, individual structures and time of
storage, making the standardization of the pillars
difficult. Therefore, several authors have employed
metallic models or resin ones for measurement of
the marginal fidelity (PERA et al.
22
, 1994; RINKE
et al.
24
1995; SHEARER et al.
25
, 1996; GROTEN
et al.
7
, 1997; SULAIMAN et al.
27
, 1997;
NAKAMURA et al.
20
, 2000; TINSCHERT et al.
28
,
2001) with some advantages. Among them, the easy
reproduction achieving and the few present varia-
bles. Groten et al.
7
(1997) affirm that, in in vitro
studies, clinical faults and disturbing parameters not
related to the confection technique can be avoided
or reduced as much as possible, and using an only
steel master model turns possible the making of all
samples up in a same initial situation.
Another point of relevance is the aspect that
concerns to the cementing of the copings. Some
authors make use of it (CHAN et al.
4
, 1989; SO-
RENSEN
26
, 1990), because they believe that the
most important inadaptability is the one that oc-
curs in vivo, when the crowns are already cemen-
ted. In our studies, as well as in Rinke et al.
24
(1995), Groten et al.
7
(1997), Sulaiman et
al.
27
(1997), Nakamura et al.
20
(2000), Tinschert et
al.
28
(2001), this was not accomplished. Tinschert
et al.
28
(2001) affirm that, when we cement the cro-
wns, we lose the precision of the primary adaptati-
on, being the influence of the cement type, visco-
sity and cementation techniques well-known. We
believed that when compared crowns construction
systems and modifications that will influence in the
precision of primary adaptation; the cementation
should not be used.
In the values observed before the application
of the sandblasting (L
0
), related only to the finish
lines preparations, we didn’t notice significant sta-
tistical differences between the two types, being
observed values of mean marginal discrepancy of
42.37µm for deep chamfer and 33.35µm the round
shoulder. In literature mean values of marginal gap
were observed inside of a great range, since 19µm,
without significant difference between deep cha-
mfer and round shoulder (SHEARER et al.
25
, 1996)
up to 161mm (SULAIMAN et al.
27
, 1997), being
our results this range. It is still observed in our stu-
dy, some standard deviations with high values, and
two causes can be the most probable to elucidate
this fact. The first is intrinsic to the evaluation
method, where four measurements points were ob-
served in each of the appraised copings. It is kno-
wn that the values of marginal adaptation are not
constant in every circumference of the cervical end,
thus, if more points were confronted the tendency
of the standard deviation fall will exist. Another
possible reason is that these copings are handma-
de, and they are liable to inherent variations to the
own making, for the laboratory technician.
The use of the silica cover in aluminized cera-
mics is a reality, considered as an effective method
to improve its union to the resinous cements by the
increase of the superficial silica content (KERN &
THOMPSON
12
, 1994; KERN & THOMPSON
13
,
1995; MARAIS & HERBST
17
, 1996; KERN &
STRUB
10
, 1998; BLIXT et al.
2
, 2000).
However, the marginal adaptation of crowns or
fixed partial prostheses submitted to this treatment
had not been evaluated in the literature. This as-
pect becomes important when applied in the inter-
nal surface of the crowns, in first place, an abrasi-
on of this surface should exist, and in second place,
there is the incorporation of silica particles to the
ceramic, changing the morphology of the internal
surface of the treated crowns. Kern & Thompson
12
(1994) didn’t obtain conclusive results to affirm that
would exist an inappropriate adaptation of the pros-
theses, due to surface alterations caused by the san-
dblasting.
The obtained results, comparing the values pre
and post application of Rocatec, demonstrate that
this surface treatment influenced negatively in the
marginal adaptation of In-Ceram crowns, in the
groups DCa and DCt, and in the groups RSt and
RSa significant statistical differences were not ob-
served, with level of significance of 5%. These
15
Hilgert E, Neisser MP, Bottino MA
EVALUATION OF THE MARGINAL ADAPTATION OF CERAMIC COPINGS IN FUNCTION OF THE CERVICAL ENDINGS AND TREATMENT OF THE
INTERNAL SURFACES
Cienc Odontol Bras 2003 out./dez.; 6 (4): 9-16
found differences, in our opinion, are not limitati-
ons for the clinical use of the Rocatec system, once
that all the marginal gap mean values found in this
study are inside of the clinically acceptable para-
meters. These values of clinical acceptance are very
controversial and without consensus in the litera-
ture, but they are situated among the mean values
of 39µm (CHRISTENSEN
5
, 1966), 50µm (PERA
et al.
22
, 1994), 50 to 74µm (HUNG et al.
9
, 1990),
70µm (WEaver et al.
29
, 1991) and 120µm (McLE-
AN & FRAUNHOFER
18
, 1971). In our study, all
the marginal gap averages in the appraised groups
are in an inferior landings of 55µm, making us be-
lieve that any of the surface treatments or finish
lines used in this study are susceptible to be used
at the clinic.
This way, with these study limitations, we no-
ticed that the influence of the finish line; round
shoulder or deep chamfer; and the surface treat-
ment with Rocatec are not big enough to make the
adaptation of the crowns be clinically unaccepta-
ble. On the other hand, it is possible that additio-
nal sandblastings, for any reasons, disarrange the
crown to the pillar tooth, owing to the cumulative
effect of this procedure.
CONCLUSION
From the broached methodology and of the
obtained results, we concluded that when analyzed
the groups pre-sandblasting to each other, there
were not significant statistical differences among
the finish lines analyzed. In the same way, when
analyzed the groups pos-sandblasting, statistical
differences were not observed among them. On the
other hand, when compared the values before and
after the treatment of the samples, there was nega-
tive influence of the sandblasting when use the deep
chamfer finish line, with relief or not in the cervi-
cal board (groups RSa and RSt).
RESUMO
Este estudo avaliou a adaptação marginal de copings cerâmicos (In-Ceram, Vita) variando o tipo de término
cervical e tratamento interno de superfície (Rocatec, ESPE). Para tal, foram usinados dois modelos-padrão em
aço com preparo para coroa totalmente cerâmica, sendo um com término cervical em ombro arredondado (O) e
o outro em chanfro largo (C). A partir de cada um deles, foram confeccionados 20 copings, e a discrepância
marginal avaliada em microscópio para medição, obtendo assim uma medida inicial. Cada grupo foi dividido em
dois outros, que receberam dois tipos de jateamento com sílica: (1) em toda superfície interna da coroa – CT e
OT – e (2) na superfície interna, mas aliviando o bordo cervical – CA e OA. As discrepâncias foram novamente
mensuradas e os dados submetidos à análise estatística. Foram observados valores de discrepância marginal
média de 42,37±18,78mm para grupo C e 33,35±20,08mm para o grupo O nas medidas iniciais, sem diferença
estatisticamente significante entre eles. Os valores iniciais e finais foram comparados para cada um dos grupos
experimentais, sendo observada diferença estatística significante em CA e CT. Não foi observada diferença
estatística entre os valores pós-jateamento. Conclui-se que ambos os términos cervicais apresentam adaptações
marginais semelhantes entre si quando não submetidos a nenhum tipo de tratamento. Quando realizado o trata-
mento de superfície, foi observada influência negativa na adaptação marginal de alguns grupos, se comparados
os valores iniciais e finais, apesar de não serem observadas diferenças entre os últimos.
UNITERMOS
Cerâmicas, propriedades de, tratamento de superfície, adaptação marginal, término cervical.
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Recebido em: 14/02/03
Aprovado em: 08/04/03
Mail adress
Edson Hilgert
Av. Francisco José Longo, 777.S. Dimas
CEP 12245-000 – São José dos Campos – SP
ehilgert@yahoo.com
... At each step (frameworks, veneering, cementation and artificial aging) a Specimen Positioning Device (SPD) 20 was used to secure the samples on their corresponding prepared teeth. Each specimen was photographed using Digital optical microscope 21 with a built-in camera connected with an IBM compatible personal computer using a fixed magnification of 40Â. A digital image analysis system 22 was used to measure and qualitatively evaluate the discrepancy width. ...
... A controversy exists, regarding the clinically acceptable marginal discrepancy. Theoretically, the restoration needs a luting cement film of 20e40 mm thickness [21]. McLean and Fraunhofer [22], stated that a marginal discrepancy of 120 mm should be the limit of clinical acceptability. ...
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Excessive marginal discrepancy of crowns favors the rate of cement dissolution and microleakage that may cause pulpal inflammation. Besides, it may increase plaque retention leading to the onset of periodontal disease. Therefore, this research was carried out to study the effect of fabrication stages and artificial aging on the marginal adaptation of CAD/CAM Zirconia-based crowns which have become increasingly popular among the patients due to their natural esthetics and excellent strength.
... 21,22 Although there are no standards in the literature in terms of preparation design for Zirconia-based all-ceramic bridges, it is recommended that an occlusal reduction of 1.5-2 mm, a facial reduction of 1-1.5 mm, a deep chamfer or circular shoulder with inner rounded angle between 1.0 and 1.5 mm wide, and an occlusal angle of convergence not greater than 10 degrees be employed. [23][24][25][26][27][28] The finish line used in this study, was rounded shoulder, since it is one of the most recommended finish lines in the literature, 29 to be used with metal free crowns. This was due to their horizontal configurations, as other finish lines were contraindicated in this prosthesis type, because thin margins tend to fracture with easiness in ceramic restorations. ...
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Objectives: This study was designed to investigate, in vitro, fracture characteristics of all-ceramic Zirconia posterior cantilever bridges (CAD / CAM milling, Cerec inLab) using different connector dimensions. Methods: Specially designed stainless steel model was constructed, and a total number of 20 posterior cantilever bridges were constructed and classified into four equal groups, five each, according to connector dimensions. The first group of FPDs was constructed using the metal-ceramic technique, with 3x3 mm con-nector area dimension. The second group of FPDs was constructed using Zirconia, with 4x3 mm connector area dimension. The third group of FPDs was constructed using Zirco-nia, with 3.5x3 mm connector area dimension. The fourth group of FPDs was constructed using Zirconia, with 4.5x3 mm connector area dimension. The samples were tested to determine the fracture resistance using Lloyd universal testing machine. Fracture pattern was then observed, and microscopic examination of randomly selected fractured bridge sample from each tested group was carried out using scanning electron microscope. Results: One-way ANOVA test showed that there was a statistically significant difference between the groups (P-value = 0.003). Pair-wise comparisons between the groups revealed that Group I (611.1 ± 102.2 N) showed the statistically significantly highest mean fracture resistance. This was followed by Group IV (538.1 ± 83.4 N). There was no statistically significant difference between Group II (441.2 ± 73 N) and Group III (404 ± 102.9 N); both showed the statistically significantly lowest mean fracture resistance values. Conclusions: the four tested groups had acceptable strength, which leads to clinical success. Posterior bridges made from Sirona inCoris ZI using (CAD / CAM milling, Cerec inLab) are with less in strength than those made of metal-ceramic using the Conventional lost wax one. The connector dimension plays a major role in reducing the stress values, as fracture load increased when the cross-sectional area of the connector became larger. Clinical implications: Zirconia can present an interesting alternative to replace metal-ceramic posterior cantilever bridge and can, therefore, encourage further clinical investigation.
... In addition to fracture resistance and esthetics, marginal accuracy is of clinical importance and influences the success and longevity of all-ceramic restorations. 2,4,5 According to the results of this study, the mean marginal discrepancies for Turkom-Cera (49.2 ± 12.2 µm), In-Ceram (71.5 ± 13.7 µm), and Procera (34.4 ± 10.9 µm) copings differ from each other significantly (P < .05). Procera crowns had the lowest marginal discrepancy, whereas In-Ceram crowns had the highest marginal discrepancy. ...
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The aim of this study was to evaluate the marginal adaptation of Turkom-Cera all- ceramic crowns compared to In-Ceram and Procera AllCeram systems. The influence of finish line design (chamfer or shoulder) on the marginal adaptation of Turkom-Cera all-ceramic crowns was also investigated. Thirty human premolars were prepared with chamfer margins and assigned to either the Turkom-Cera, In-Ceram, or Procera system group. In addition, 10 premolars were prepared with rounded shoulder finish lines and assigned to an additional Turkom-Cera group. Ceramic copings (0.6-mm thick) were fabricated for each group following the manufacturers’ instructions. The copings were seated on abutments using a special holding device that facilitated uniform loading, and marginal adaptation was assessed using a stereomicroscope. Data were analyzed using analysis of variance, the Tukey HSD post hoc test, and an independent samples t test. There was a statistically significant difference regarding marginal adaptation among the three all-ceramic systems (P < .05). There were no significant differences in the mean marginal discrepancies of Turkom-Cera crowns among chamfer and shoulder finish line groups (P > .05). Within the limitations of this study, the marginal discrepancies were all within the clinically acceptable standard.
... Hilgert showed that the addition of porcelain to the InCeram coping and repeated firing cycles involved in building a crown did not alter the fittness. [22] Values proposed in the literature as acceptable marginal adaptations vary depending on the type of restoration and author McLean and Von Fraunhofer, [13] in a clinical study on 100 restorations in a 5-year period concluded that 120 µm represents the maximum clinically acceptable misfit. All the results in this study, except for labial and proximal surfaces of InCeram, therefore, would not be clinically acceptable. ...
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... Ese método, a pesar de ser bastante utilizado, presenta algunas desventajas como: número reducido de mediciones, imposibilidad de mediciones en las diferentes etapas de confección de la restauración y necesidad de tratamiento de superficie, lo que puede distorsionar la muestra del espécimen y alterar el resultado (28). Por los motivos expuestos, en este estudio fue realizada la medición de las grietas marginales de los especimenes no seccionados y directamente con microscopia electrónica de barrido (2,21,34,43,44). ...
Article
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... In addition to fracture resistance and esthetics, marginal accuracy is of clinical importance and influences the success and longevity of all-ceramic restorations. 2,4,5 According to the results of this study, the mean marginal discrepancies for Turkom-Cera (49.2 ± 12.2 µm), In-Ceram (71.5 ± 13.7 µm), and Procera (34.4 ± 10.9 µm) copings differ from each other significantly (P < .05). Procera crowns had the lowest marginal discrepancy, whereas In-Ceram crowns had the highest marginal discrepancy. ...
Article
Full-text available
The aim of this study was to evaluate the marginal adaptation of Turkom-Cera all-ceramic crowns compared to In-Ceram and Procera AllCeram systems. The influence of finish line design (chamfer or shoulder) on the marginal adaptation of Turkom-Cera all-ceramic crowns was also investigated. Thirty human premolars were prepared with chamfer margins and assigned to either the Turkom-Cera, In-Ceram, or Procera system group. In addition, 10 premolars were prepared with rounded shoulder finish lines and assigned to an additional Turkom-Cera group. Ceramic copings (0.6-mm thick) were fabricated for each group following the manufacturers' instructions. The copings were seated on abutments using a special holding device that facilitated uniform loading, and marginal adaptation was assessed using a stereomicroscope. Data were analyzed using analysis of variance, the Tukey HSD post hoc test, and an independent samples t test. There was a statistically significant difference regarding marginal adaptation among the three all-ceramic systems (P < .05). There were no significant differences in the mean marginal discrepancies of Turkom-Cera crowns among chamfer and shoulder finish line groups (P > .05). Within the limitations of this study, the marginal discrepancies were all within the clinically acceptable standard. Int J Prosthodont 2011;24:379-381.
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To satisfy the requirement of dental chair‐side clinical technique, zirconia ceramics is required to be sintered in one hour; the effect of rapid‐speed sintering dwelling time on dental zirconia were investigated. The relative density was measured through Archimedes method; Scanning electron microscopy and X‐ray diffractometer were employed to characterize the microstructures; Universal mechanical test machine and Vickers indenter were used to evaluate the mechanical properties; Spectrophotometer was utilized to analyze the optical transmittance, and optical microscope was used to estimate the marginal adaptation of zirconia crown with abutment. Previous results indicated that rapid‐speed sintering and dwelling at 1580 °C for 20 min could help dental zirconia achieve adaptable clinical performances with bending strength of around 1151 MPa, hardness of 13.3 GPa and fracture toughness of 5.92 MPa•m1/2, as well as adaptable optical transmittance and marginal adaptation. This article is protected by copyright. All rights reserved.
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Marginal discrepancies have been one of the main fears to researchers in achieving fine quality adaptation in dental prostheses. Respected authors have presented results with seemingly incoherent values as, worse vertical seating of the crowns before than after cementation, even due to the existence of a cement film interposed between the surfaces. This occurrence took us to accomplish the present study. To simulate crown preparations and the full crowns, ten stan- dardized models and ten capsules, in stainless steel, shaped and adjusted each other by means of a power lathe were used. The height, diameter and taper were standardized and similar to natural molars. A device was developed to main- tain a constant pressure of 5kg during the measurements of all samples (standard models and capsules juxtaposed). The measurements were done before and after cementations, in the long axis sense of the samples. The cement used was zinc phosphate cement. The measurements were accompli- shed with a horizontal metroscope Carl Zeiss, with a reso- lution of 0,0001mm. The results always showed larger valu- es after cementations. As the only varied factor was the presence or not of cement, it was licit and coherent to con- clude that the vertical discrepancy could have happen due to the presence of a cement film.
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The In-Ceram technique uses alumina ceramics and glass in a two-step firing procedure to create a high-strength core material for single-tooth restorations as well as small fixed partial dentures. Fine-grain alumina particles are sintered to form a porous substructure, which is infiltrated with molten glass. The combination of these two processes gives the material its outstanding properties. The sintering process is almost without shrinkage, providing an excellent fit, while the glass infiltration leaves practically no porosities, resulting in high strength.
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Tooth preparations and seating techniques of castable ceramic crowns differ from metal ceramic crowns. This study evaluated the variable effects of cementation on the marginal adaptation of Dicor, Cerestore, and porcelain-fused-to-metal crowns. The shoulder preparation was maintained for ceramic crowns, and a cavosurface bevel was designed for metal ceramic crowns. Crowns were made with a replication size of 10, placed on master dies, and the marginal openings measured with a Nikon Measurescope 20 instrument. Thirty crowns were cemented with zinc phosphate cement and the recommended clinical force. Marginal adaptation was not improved with a gingival bevel preparation or an increased seating force. The best marginal adaptation was recorded for Cerestore crowns.
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This case report describes the clinical and laboratory procedures for the fabrication and insertion of In-Ceram all-porcelain, resin-bonded bridges. All-porcelain crowns and fixed partial dentures have better biocompatibility and better esthetic results than do ceramometal restorations. In-Ceram has been shown to have better physical properties than other ceramic or glass materials. However, long-term clinical studies of the material are not yet available.
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Previous research on crown margin fidelity is reviewed and methods of measurement are compared and scrutinized. A standardized method for the determination of crown margin fidelity is introduced. A biologically oriented rationale is presented for analysis of the measurement parameters. This system places a strong emphasis on measuring factors that impact upon accumulation of plaque and the microbiologic environment around crowns, ultimately affecting gingival health. Crown samples were cemented on master dies and were embedded for sectioning buccolingually and mesiodistally. Photographs of margins with plastic overlays indicating emergence profiles were used to determine vertical and horizontal marginal discrepancies. Three observers measured seven crown systems for the vertical and horizontal marginal discrepancies of each crown system. The interobserver variance was 10 microns for the horizontal and 9 microns for the vertical marginal discrepancy.
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The marginal fit of Dicor, Cerestore, and porcelain-fused-to-metal crowns was evaluated. Ten premolars free of caries were prepared for each type of restoration and crowns were made. The vertical marginal openings were measured before cementation, after cementation, and after thermocycling. There were statistically significant differences between all three test conditions in each type of crown, between Dicor and porcelain-fused-to-metal crowns after cementation and after thermocycling, and between Cerestore and porcelain-fused-to-metal crowns after thermocycling. All 30 cemented crowns were then embedded in acrylic resin for serial sections for measurement of absolute marginal openings. Statistically significant differences between Dicor and Cerestore crowns and between Cerestore and porcelain-fused-to-metal crowns were found. It was concluded that marginal openings increased after cementation and after thermocycling, and porcelain-fused-to-metal crowns had significantly better marginal fit than that of Dicor and Cerestore crowns.
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The terminology describing "fit" and the techniques used for measuring fit vary considerably in the literature. Although fit can be most easily defined in terms of "misfit," there are many different locations between a tooth and a restoration where the measurements can be made. In this work, the measurements of misfit at different locations are geometrically related to each other and defined as internal gap, marginal gap, vertical marginal discrepancy, horizontal marginal discrepancy, overextended margin, underextended margin, absolute marginal discrepancy, and seating discrepancy. The significance and difference in magnitude of different locations are presented. The best alternative is perhaps the absolute marginal discrepancy, which would always be the largest measurement of error at the margin and would reflect the total misfit at that point.