Citation: Watanabe, S.; Nakano, T.;
Ono, S.; Yamanishi, Y.; Matsuoka, T.;
Ishigaki, S. Fracture Resistance of
Zirconia Abutments with or without
a Titanium Base: An In Vitro Study
for Tapered Conical Connection
Implants. Materials 2022, 15, 364.
https://doi.org/10.3390/
ma15010364
Academic Editors: Alberto
Campagnolo, Alberto Sapora and
Tomasz Czujko
Received: 23 November 2021
Accepted: 2 January 2022
Published: 5 January 2022
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Article
Fracture Resistance of Zirconia Abutments with or without a
Titanium Base: An In Vitro Study for Tapered Conical
Connection Implants
Shota Watanabe , Tamaki Nakano * , Shinji Ono , Yasufumi Yamanishi, Takashi Matsuoka
and Shoichi Ishigaki
Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry, 1–8 Yamadaoka, Suita,
Osaka 565-0871, Japan; watanabe.shota.dent@osaka-u.ac.jp (S.W.); onoshin@dent.osaka-u.ac.jp (S.O.);
y-yamani@dent.osaka-u.ac.jp (Y.Y.); matsuoka.takashi.dent@osaka-u.ac.jp (T.M.);
ishigaki.shoichi.dent@osaka-u.ac.jp (S.I.)
* Correspondence: nakano.tamaki.dent@osaka-u.ac.jp; Tel.: +81-6-6879-2946
Abstract:
Dental implants with tapered conical connections are often combined with zirconia abut-
ments for esthetics; however, the effect of the titanium base on the implant components remains
unclear. This study evaluated the effects of a titanium base on the fracture resistance of zirconia
abutments and damage to the tapered conical connection implants. Zirconia (Z) and titanium base
zirconia (ZT) abutments were fastened to Nobel Biocare (NB) implants and Straumann (ST) implants
and subjected to static load testing according to ISO 14801:2016. The experiments were performed
with 3 mm of the platform exposed (P3) and no platform exposed (P0). The fracture loads were
statistically greater in the titanium base abutments than the zirconia abutments for the NB and ST
specimens in the P0 condition. In the P3 condition of the ST specimens, the deformation volume of
the ZT group was significantly greater than the Z group. The titanium base increased the fracture
resistance of the zirconia abutments. Additionally, the titanium base caused more deformation in
the P3 condition. The implant joint design may also affect the amount of damage to the implants
when under a load. The mechanical properties of the abutment should be considered when selecting
a clinical design.
Keywords: zirconia abutment; titanium base; tapered conical connection; static load
1. Introduction
In dental implant treatments, especially in the esthetic zone, zirconia abutments are
desired because of their superior esthetics and biocompatibility [
1
,
2
]. Currently used zirco-
nia abutments are classified according to differences in the implant–abutment connection,
and there have been various comparative studies on the mechanical properties of zirco-
nia abutments in conventional connection modes (external butt joints and internal butt
joints) [3,4].
A further classification was recently proposed to distinguish between two-piece abut-
ments with a titanium base in the connecting part and one-piece abutments comprised en-
tirely of zirconia [
5
]. Several studies have compared the mechanical properties of both types.
Several
in vitro
studies have reported that titanium base zirconia abutments were
significantly more resistant to a bending moment than zirconia abutments [
2
,
6
–
10
]. Fur-
thermore, the titanium base type is advantageous from a mechanical viewpoint because the
titanium in the connecting part is likely to cause less wear in the implant body [8,11,12].
However, these mechanical studies often use different implant bodies [
2
,
6
–
10
] or
compare samples produced by different computer-aided design/computer-aided manu-
facturing (CAD/CAM) systems [
2
,
6
–
10
]. How the inclusion of a titanium base affects the
mechanical properties of zirconia abutments has not been evaluated using actual products.
Materials 2022, 15 , 364. https://doi.org/10.3390/ma15010364 https://www.mdpi.com/journal/materials
