University of Zurich
Zurich Open Repository and Archive
Winterthurerstr. 190
CH-8057 Zurich
http://www.zora.uzh.ch
Year: 2008
A systematic review of the 5-year survival and complication
rates of implant-supported single crowns
Jung, R E; Pjetursson, B E; Glauser, R; Zembic, A; Zwahlen, M; Lang, N P
Jung, R E; Pjetursson, B E; Glauser, R; Zembic, A; Zwahlen, M; Lang, N P (2008). A systematic review of the
5-year survival and complication rates of implant-supported single crowns. Clinical Oral Implants Research,
19(2):119-130.
Postprint available at:
http://www.zora.uzh.ch
Posted at the Zurich Open Repository and Archive, University of Zurich.
http://www.zora.uzh.ch
Originally published at:
Clinical Oral Implants Research 2008, 19(2):119-130.
Jung, R E; Pjetursson, B E; Glauser, R; Zembic, A; Zwahlen, M; Lang, N P (2008). A systematic review of the
5-year survival and complication rates of implant-supported single crowns. Clinical Oral Implants Research,
19(2):119-130.
Postprint available at:
http://www.zora.uzh.ch
Posted at the Zurich Open Repository and Archive, University of Zurich.
http://www.zora.uzh.ch
Originally published at:
Clinical Oral Implants Research 2008, 19(2):119-130.
A systematic review of the 5-year survival and complication
rates of implant-supported single crowns
Abstract
OBJECTIVES: The objective of this systematic review was to assess the 5-year survival of
implant-supported single crowns (SCs) and to describe the incidence of biological and technical
complications. METHODS: An electronic MEDLINE search complemented by manual searching was
conducted to identify prospective and retrospective cohort studies on SCs with a mean follow-up time of
at least 5 years. Failure and complication rates were analyzed using random-effects Poisson's regression
models to obtain summary estimates of 5-year proportions. RESULTS: Twenty-six studies from an
initial yield of 3601 titles were finally selected and data were extracted. In a meta-analysis of these
studies, survival of implants supporting SCs was 96.8% [95% confidence interval (CI): 95.9-97.6%]
after 5 years. The survival rate of SCs supported by implants was 94.5% (95% CI: 92.5-95.9%) after 5
years of function. The survival rate of metal-ceramic crowns, 95.4% (95% CI: 93.6-96.7%), was
significantly (P=0.005) higher than the survival rate, 91.2% (95% CI: 86.8-94.2%), of all-ceramic
crowns. Peri-implantitis and soft tissue complications occurred adjacent to 9.7% of the SCs and 6.3% of
the implants had bone loss exceeding 2 mm over the 5-year observation period. The cumulative
incidence of implant fractures after 5 years was 0.14%. After 5 years, the cumulative incidence of screw
or abutment loosening was 12.7% and 0.35% for screw or abutment fracture. For supra-structure-related
complications, the cumulative incidence of ceramic or veneer fractures was 4.5%. CONCLUSION: It
can be concluded that after an observation period of 5 years, high survival rates for implants and
implant-supported SCs can be expected. However, biological and particularly technical complications
are frequent.
1
A systematic review of the survival and
complication rates of implant supported single
crowns after an observation period of at least 5
years
Ronald E. Jung
1
, Bjarni E. Pjetursson
2
, Roland Glauser
3
, Anja Zembic
1
,
Marcel Zwahlen
4
and Niklaus P. Lang
1
1) Department of Fixed and Removable Prosthodontics and Dental Material
Science, University of Zurich, Switzerland
2) University of Berne School of Dental Medicine, Berne, Switzerland
3) Private Practice, Zürich, Switzerland
4) Division of Epidemiology and Biostatistics, Department of Social and
Preventive Medicine, University of Berne, Bern, Switzerland
Running head: Systematic review of SCs.
Key words: Implant dentistry, single crowns, systematic review, survival,
success, longitudinal, failures, complication rates, technical complications,
biological complications, periimplantitis.
Address for correspondence: Dr. Ronald E. Jung
Department of Fixed and Removable
Prosthodontics and
Dental Material Science
Dental School, University of Zurich
Plattenstrasse 11
CH-8032 Zurich, Switzerland
Phone: +41 44 634 32 51
Fax: +41 44 634 43 05
e-mail: jung@zzmk.unizh.ch
2
Abstract
Objectives:
The objective of this systematic review was to assess the 5 year survival of
implant supported single crowns (SCs) and to describe the incidence of
biological and technical complications.
Methods:
An electronic Medline search complemented by manual searching was
conducted to identify prospective and retrospective cohort studies on SCs
with a mean follow-up time of at least 5 years. Failure and complication rates
were analyzed using random-effects Poisson regression models to obtain
summary estimates of 5-year proportions.
Results:
Twenty-six studies from an initial yield of 3601 titles were finally selected and
data were extracted. In a meta-analysis of these studies survival of implants
supporting SCs was 96.8% (95 percent confidence interval (C.I.): 95.9-97.6%)
after 5 years. The survival rate of SCs supported by implants was 94.5% (95
CI: 92.5-95.9%) after 5 years of function. The survival rate of metal-ceramic
crowns, 95.4% (95 CI: 93.6-96.7%) was significantly (p=0.005) higher than
the survival rate, 91.2% (95 CI: 86.8-94.2%) of all-ceramic crowns.
Periimplantitis and soft tissue complications occurred in 9.7% of the SCs and
6.3% of the implants had bone loss exceeding 2 mm over the 5 years
observation period. Technical complications included implant fractures,
connection-related and supra-structure related complications. The cumulative
incidence of implant fractures after 5 years was 0.14%. After 5 years the
cumulative incidence of connection-related complications was 12.7% for
screw or abutment loosening and 0.35% for screw or abutment fracture. For
supra-structure related complications the cumulative incidence of ceramic or
veneer fractures was 4.5%.
3
Conclusion:
Despite of high survival rates for implants and implant supported single
crowns, biological and particularly technical complications are frequent. To
describe and compare the long-term outcomes of implant supported SCs
more studies with follow-up times of at least 10 years are required.
Introduction
The range of indications in implant dentistry was broadened in the past
decades from fully edentulous to partially edentulous jaws. The therapy of
single tooth gaps has become a frequent and important indication in current
dentistry. A variety of therapeutic options are available to restore a single
tooth gap. These therapies range from resin-bonded bridges, to fixed partial
dentures up to the use of implant supported single crowns (Kerschbaum et al.
1996; Palmqvist & Swartz 1993; Romeo et al. 2004). Decision making in
these indications should be based on clinical and radiographic assessments
and on the knowledge of the long-term survival and complication rates of each
of these therapeutic options.
The outcome of implant therapy has been presented in the majority of clinical
studies by focusing only on implant survival without providing detailed
information on the reconstructions (e.g. Buser et al. 1996; Vigolo & Givani
2000; Romeo et al. 2004). However, for decision making it is important to
know the survival proportions and the determination of the incidence of
biological and technical complications not only for the implants but also for the
reconstructions. In addition, for a meaningful interpretation of the survival and
complication rate a mean follow-up period of at least 5 years would be
required (Pjetursson et al. 2004).
In order to evaluate the outcome of a treatment modality on the highest level
of evidence the use of systematic reviews has been proposed to be an
appropriate method (Egger et al. 2001). Hence, systematic reviews are
employed in medicine and dentistry to summarize cumulative information on
the optimal treatment for clinically important questions.