Clinical experience with In-Ceram Spinell crowns: 5-year follow-up.

Abstract

Prompted by increased patient requests for esthetic treatment, restorative clinicians have evaluated a variety of new materials and procedures. This study reports on 5 years' experience with In-Ceram Spinell all-ceramic crowns. A total of 40 anterior crowns were positioned in 13 patients from October 1995 to December 1998. The clinical examination was made following modified California Dental Association/Ryge criteria. Final evaluation was carried out in October 2000, for an observation period of 22 to 60 months (mean 50 months). Only one failure was recorded, and the fractured crown needed to be replaced; according to Kaplan-Meier analysis, the estimated success rate was 97.5%. A thorough description of the clinical procedures through which anterior teeth can be successfully treated with all-ceramic Spinell crowns is described.

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The International Journal of Periodontics & Restorative Dentistry

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In an attempt to provide better
results in the face of increased
demand for esthetic treatment, in
recent years restorative clinicians
have ventured to employ new mate-
rials and techniques. The traditional
metal-ceramic system offers maxi-
mum strength, but its light trans-
mission characteristics are com-
pletely different from those of a
natural tooth because of its metal
framework.1
The use of all-ceramic restora-
tions can give a final result compa-
rable to that of natural teeth to
achieve optimal esthetic results. The
final appearance of all-ceramic
restorations largely depends on the
light-transmission properties of the
ceramic material, and therefore on
its composition.2Additionally, all-
ceramic restorations seem to show
acceptable long-term stability com-
bined with good strength and resis-
tance once bonded, especially in the
anterior area.3–5Overall clinical suc-
cess is further supported by an
acceptable marginal fit6,7generally
ascribed to this kind of restoration.
The principal all-ceramic sys-
tems developed to date can be
Clinical Experience with In-Ceram
Spinell Crowns: 5-Year Follow-up
Mauro Fradeani, MD, DDS*
Augusto Aquilano, DDS**
Marcantonio Corrado, MD, DDS***
Prompted by increased patient requests for esthetic treatment, restorative clini-
cians have evaluated a variety of new materials and procedures. This study reports
on 5 years’ experience with In-Ceram Spinell all-ceramic crowns. A total of 40
anterior crowns were positioned in 13 patients from October 1995 to December
1998. The clinical examination was made following modified California Dental
Association/Ryge criteria. Final evaluation was carried out in October 2000, for an
observation period of 22 to 60 months (mean 50 months). Only one failure was
recorded, and the fractured crown needed to be replaced; according to Kaplan-
Meier analysis, the estimated success rate was 97.5%. A thorough description of
the clinical procedures through which anterior teeth can be successfully treated
with all-ceramic Spinell crowns is described. (Int J Periodontics Restorative Dent
2002;22:525–533.)
***Adjunct Associate Professor, Department of Prosthodontics, Louisiana
State University, New Orleans; and Private Practice, Pesaro and Milano,
Italy.
***Private Practice, Pesaro, Italy.
***Private Practice, Monselice, Padova, Italy.
***Reprint requests: Dr Mauro Fradeani, Corso XI Settembre 92, 61100
Pesaro, Italy.
525
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divided into two categories: glass
ceramics and alumina-based ceram-
ics. Glass-ceramic materials, such as
Dicor (Dentsply), the leucite-rein-
forced glass ceramic Optec HSP
(American Thermocraft), and the
leucite-reinforced pressed glass
ceramic IPS Empress (Ivoclar), can
guarantee some excellent qualities
of light transmission and translu-
cency, very similar to those of a nat-
ural tooth.5,8
Despite excellent esthetic prop-
erties, these pressed glass ceramics
have been proven in several studies
to possess inferior mechanical char-
acteristics when compared to alu-
mina-based crowns.9A high flexural
strength value (320 to 600 MPa) is
the most positive feature of the alu-
mina systems,10–15which include In-
Ceram (Vita) and, most recently, the
Procera system (Nobel Biocare).
These have demonstrated accept-
able marginal fit6,16,17and good
esthetic results; however, they do
not possess the same light-trans-
mission features achieved by the use
of glass-ceramic material. This fact
negates a satisfactory natural look on
anterior restorations, especially with
In-Ceram material, where problems
evident in transilluminating light are
caused by the semiopaque oxide
core material.18,19
To overcome this problem, the
same manufacturer developed the
In-Ceram Spinell system (Spinell-
Core and Vitadur-?, Vita). This new
material is based on a mixture of
magnesium oxide and aluminum
oxide. The different core material
(MgAl2O4) of the new In-Ceram
Spinell system is therefore more
translucent than the previous In-
Ceram Alumina core. It is able to
offer glass-like light transmission,
and, accordingly, a more natural
appearance to the final restora-
tions.18,19Its mechanical resistance
characteristics are, however, lower
when compared to original In-Ceram
Alumina system. Therefore, its use is
recommended only in the anterior
area.
The purpose of this investiga-
tion was to clinically evaluate In-
Ceram Spinell crowns.
Method and materials
Study group
The study population consisted of
13 patients (10 women and three
men) with an age distribution of 48.3
years. Forty In-Ceram Spinell crowns
were positioned from October 1995
to December 1998 in the authors’
private practice; four crowns were
placed in 1995, 33 were placed in
1996, and three were placed in
1998. Twenty-two crowns were posi-
tioned on central incisors (two
mandibular), 14 on lateral incisors
(two mandibular), and four on
canines (zero mandibular). Natural
teeth were present in the opposing
arch of 67.5% of the patients, while
32.5% of the patients had opposing
ceramic material.
Teeth restored with crowns had
been affected by several problems:
old failed restorations, inadequate
old crowns, endodontically treated
teeth, and fractured or abraded
teeth. Twenty-three (57.5%) crowns
were placed on endodontically
treated teeth, and the remaining 17
(42.5%) crowns were placed on vital
teeth. Vital teeth were restored with
composite material, while endodon-
tically treated teeth received com-
posite buildup or, where significant
tooth structure was missing, a zirco-
nia post with a composite core or
metal-ceramic post and core.20
Fifteen teeth examined required a
crown lengthening procedure in the
anterior area because existing
restorations presented deep mar-
gins that violated the connective tis-
sue attachment.
A minimum 6-month healing
period allowed final maturation prior
to finalizing the restorations. From a
minimum of 3 months to a maximum
of 6 months, patients returned for
oral hygiene recall appointments,
depending on their periodontal con-
dition. The requisite for inclusion in
this study was no bleeding on prob-
ing (to indicate the absence of
inflammation).
Clinical and laboratory
procedures
Each restoration was positioned in
the anterior region according to
the manufacturer’s recommenda-
tions. Tooth preparation was per-
formed circumferentially, creating a
90-degree rounded axiogingival
line angle 1.2 to 1.5 mm deep by
using rotary diamond and hand
instruments for the margins. This
shape guarantees the structure
maximum resistance. All internal
angles were rounded to reduce the
526
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stress concentration during func-
tion and cementation. The taper of
the preparation was between 5 and
10 degrees, depending on abut-
ment length. In the lingual area, a
minimum thickness of 1.0 mm and
a well-defined concavity were
established to provide a correct
anatomic anterior disclusion. The
thickness of the alumina core was
between approximately 0.5 and 0.6
mm.
A transparent matrix derived
from diagnostic wax was made to
check preparation thickness. The
thickness of the provisional restora-
tions was measured to confirm the
quantity of available space for the
definitive restorations. An impression
of the provisional restoration was
made to serve as a prototype for the
final work.
The location of the gingival mar-
gin was carefully selected in relation
to the esthetic and functional
demands of each area of the single
restoration. In the lingual area, the
margin was generally located
supragingivally. This offers certain
Interocclusal registrations were
recorded, and, if necessary, a face-
bow was used to relate the master
casts to a semiadjustable articulator
(Denar Mark II, Denar). All crowns
were fabricated by the same dental
technician following the manufac-
turer’s instructions and recording
occlusal and axial thickness.
The impression was poured,
and a stone model was obtained.
The master cast was then duplicated
with a special plaster. The Spinell
powder (aluminum and magnesium
oxide) was mixed with a special liq-
uid, forming a “slip” (Fig 3) that was
applied to the duplicated stone
cast. The coping was checked on
the original die stone (Fig 4) and
then glass infiltrated in a separate
stage, achieving its maximum
strength (350 MPa) (Fig 5). Alumina
porcelain (Vitadur-?) was then lay-
ered over the coping to build up
the final restoration, adding fluo-
rescent porcelain (Luminaries Artist
Line, Vita) to compensate for the
lack of fluorescence typical of this
material.19
advantages, such as easy impression
making and evaluation of marginal
adaptation, while helping to main-
tain periodontal health. The facial
and interproximal area margins were
located at the gingival crest or
slightly into the sulcus to create the
best esthetic result (Figs 1 and 2).
When an intracrevicular margin was
performed, a gingival displacement
was obtained using knitted retrac-
tion cord No. 00 (Ultrapack,
Ultradent) soaked in hemostatic
solution (Hemodent, Premier Dental
Products). No displacement was
needed in supragingivally prepared
teeth.
The one-step double mixing
impression technique was followed,
using a light-activated custom tray
(Palatray LC, Heraeus Kulzer) for the
final impression. After cord removal,
the final impression was made using
a polyether material (Permadyne,
ESPE) or a polyvinyl siloxane mater-
ial (Extrude, Kerr). An impression of
the opposing dentition was taken
using an irreversible hydrocolloid
material (Jeltrate, Dentsply/Caulk).
527
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Fig 1
Preoperative anterior view of abraded dentition.
Fig 2
Both maxillary central incisors and the left lateral incisor will be
restored with single spinell crowns.
Retraction cords are placed prior to impression taking.

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The provisional restorations
were luted using eugenol-free mate-
rial (Freegenol, GC) or a temporary
composite cement (Provilink,
Vivadent). Before luting the final
restoration, once the provisionals
had been removed, the abutments
were carefully cleaned using a non-
fluoridated cleaning paste. The indi-
vidual crowns were carefully evalu-
ated in terms of proximal contacts,
occlusal relationship, shade match,
surface texture, contour, and mar-
ginal adaptation. Minimal occlusal
adjustments were performed prior
to cementation, leaving final
occlusal verification until after
cementation.
The internal surfaces of the fin-
ished crowns were conditioned by
air abrasion (pressure 2.5 bars, grain
size maximum 50 µm), then washed
with water and dried. A gingival
cord was placed in the sulcus prior
to luting to permit total removal of
the residual cement from the crevice
and to prevent sulcular humidity.
Phosphoric acid (35%; Ultra-Etch,
Ultradent) was applied to enamel
and dentin for 15 seconds, then
washed with water and gently dried.
The self-etching primer ED Primers
(Kuraray) was applied for 60 sec-
onds to the prepared tooth struc-
ture, without any additional etch-
ing. This was followed by gentle
drying and no rinsing. The self-cur-
ing resin cement Panavia 21 TC
(Kuraray) was used to bond the
restorations to the abutments21
(Figs 6 and 7). Before polymeriza-
tion, a brush and dental floss were
used interproximally to remove the
excess cement. Oxyguard II
(Kuraray) was placed to cover the
margins of crowns for 6 minutes,
then washed with water. Occlusion
was carefully evaluated.
528
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Fig 5
glass to allow great traslucency.
Copings are infiltrated by spinell
Fig 4
ted in the original die stone before glass
infiltration.
After sintering, the copings are fit-
Fig 3
a special refractory die where the spinell
powder is molded.
Original die stone is duplicated in
Fig 6
Three final spinell crowns.
Fig 7
at the patient’s request.
Closeup view of the central incisors. The diastema was left