ArticlePDF Available

Effectiveness of Implant Therapy Analyzed in a Swedish Population: Early and Late Implant Loss

Authors:

Abstract and Figures

Treatment outcomes in implant dentistry have been mainly assessed as implant survival rates in small, selected patient groups of specialist or university clinical settings. This study reports on loss of dental implants assessed in a large and randomly selected patient sample. The results were aimed at representing evaluation of effectiveness of implant dentistry. Using the national data register of the Swedish Social Insurance Agency, 4,716 patients were randomly selected. All had been provided with implant-supported restorative therapy in 2003. Patient files of 2,765 patients (11,311 implants) were collected from more than 800 clinicians. Information on patients, treatment procedures, and outcomes related to the implant-supported restorative therapy was extracted from the files. In total, 596 of the 2,765 subjects, provided with 2,367 implants, attended a clinical examination 9 y after therapy. Implant loss that occurred prior to connection of the supraconstruction was scored as an early implant loss, while later occurring loss was considered late implant loss. Early implant loss occurred in 4.4% of patients (1.4% of implants), while 4.2% of the patients who were examined 9 y after therapy presented with late implant loss (2.0% of implants). Overall, 7.6% of the patients had lost at least 1 implant. Multilevel analysis revealed higher odds ratios for early implant loss among smokers and patients with an initial diagnosis of periodontitis. Implants shorter than 10 mm and representing certain brands also showed higher odds ratios for early implant loss. Implant brand also influenced late implant loss. Implant loss is not an uncommon event, and patient and implant characteristics influence outcomes (ClinicalTrials.gov NCT01825772). © International & American Associations for Dental Research 2014.
Content may be subject to copyright.
1S
JDR Clinical Research Supplement
vol. XX • issue X • suppl no. X
DOI: 10.1177/0022034514563077. 1Department of Periodontology, Institute of Odontology, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden;
*corresponding author, jan.derks@odontologi.gu.se
A supplemental appendix to this article is published electronically only at http://jdr.sagepub.com/supplemental.
© International & American Associations for Dental Research
J. Derks1*, J. Håkansson1, J.L. Wennström1, C. Tomasi1, M. Larsson1, and T. Berglundh1
Effectiveness of Implant Therapy
Analyzed in a Swedish Population:
Early and Late Implant Loss
CLINICAL INVESTIGATIONS
Abstract:
Treatment outcomes in
implant dentistry have been mainly
assessed as implant survival rates in
small, selected patient groups of spe-
cialist or university clinical settings.
This study reports on loss of dental
implants assessed in a large and ran-
domly selected patient sample. The
results were aimed at representing
evaluation of effectiveness of implant
dentistry. Using the national data reg-
ister of the Swedish Social Insurance
Agency, 4,716 patients were randomly
selected. All had been provided with
implant-supported restorative therapy
in 2003. Patient files of 2,765 patients
(11,311 implants) were collected from
more than 800 clinicians. Information
on patients, treatment procedures,
and outcomes related to the implant-
supported restorative therapy was
extracted from the files. In total, 596 of
the 2,765 subjects, provided with 2,367
implants, attended a clinical exami-
nation 9 y after therapy. Implant loss
that occurred prior to connection of the
supraconstruction was scored as an
early implant loss, while later occur-
ring loss was considered late implant
loss. Early implant loss occurred in
4.4% of patients (1.4% of implants),
while 4.2% of the patients who were
examined 9 y after therapy pre-
sented with late implant loss (2.0% of
implants). Overall, 7.6% of the patients
had lost at least 1 implant. Multilevel
analysis revealed higher odds ratios for
early implant loss among smokers and
patients with an initial diagnosis of
periodontitis. Implants shorter than
10 mm and representing certain
brands also showed higher odds
ratios for early implant loss. Implant
brand also influenced late implant
loss. Implant loss is not an uncom-
mon event, and patient and implant
characteristics influence outcomes
(ClinicalTrials.gov NCT01825772).
KEY WORDS
: endosseous dental
implantation, implant-supported den-
tal prosthesis, adverse effects, multivar-
iate analysis, survival rate, treatment
outcome.
Introduction
Restorative therapy using dental
implants is considered a safe and
predictable treatment procedure in
edentulous and partially dentate patients
(Jung et al. 2012; Pjetursson et al. 2012).
The main outcome variable reported
in longitudinal studies is the rate of
implant survival, and data are based on
the proportion and number of implants,
while information on proportions of
affected patients is rare (Berglundh
et al. 2002). The documentation is also
predominantly based on assessments
made in small, selected patient groups
(i.e., so-called convenience samples)
(Tomasi and Derks 2012), and treatment
was in most cases performed by
clinicians in specialist or university
clinical settings. Thus, treatment
outcomes were mainly assessed
in efficacy evaluations rather than
appraisals of effectiveness (Berglundh
and Giannobile 2013). It is important
to adapt to recommendations on
improvement of reporting on treatment
outcomes (Tonetti and Palmer 2012)
and to address the need for randomly
selected and appropriately sized patient
groups treated by different categories of
clinicians.
The adult population in Sweden
is provided with federal financial
support for dental care, including
implant-supported restorative therapy,
which is administered by the Swedish
Social Insurance Agency (SSIA,
Försäkringskassan). In 2003, the federal
subsidies increased for patients 65 y of
at Gothenburg University Library on December 11, 2014 For personal use only. No other uses without permission.jdr.sagepub.comDownloaded from
© International & American Associations for Dental Research 2014
2S
JDR Clinical Research Supplement Month XXXX
age, resulting in a dominance of implant-
supported restorative therapy among
treatment procedures in this group of
patients.
In this study, we report on loss of
dental implants assessed in a large
and randomly selected patient sample.
The national data register of the SSIA
provided unique access to a group of
patients who had received implant-
supported restorative therapy. The results
were aimed at representing evaluation of
the effectiveness of implant dentistry.
Materials and Methods
The study protocol was approved
by the regional Ethical Committee,
Gothenburg, Sweden (Dnr 290-10)
and registered at ClinicalTrials.gov
(NCT01825772). Strengthening the
Reporting of Observational Studies in
Epidemiology (STROBE) guidelines
were followed. The study consisted of
an analysis of patient files and a clinical
evaluation about 9 y after completion of
implant-supported restorative therapy.
Study Sample
The patient material used in the present
study has been previously described
(Derks et al. 2014). Briefly, 4,716 subjects
in 2 age groups (45–54 y and 65–74 y in
2003) provided with implant-supported
restorative therapy in 2003 were randomly
selected from the national data register of
the SSIA. All subjects were contacted by
letter and asked for consent to access their
patient files. Name and social security
number, unique to each individual, were
used to identify all subjects.
Analysis of Patient Files
Documentation related to the implant-
supported restorative therapy was
requested from the respective dental
clinicians of all consenting patients.
All patient files were copied and
subsequently returned. Reported
information regarding patients, treatment
procedures, and treatment outcomes
was extracted from the patient files and
entered into a database by 2 examiners
(J.D. and M.L.). Patient data included
information on history of diabetes,
cardiovascular diseases, and periodontitis
at the time of implant therapy. Patients
were categorized as smokers if reported
to be smoking at the time of implant
therapy. All other patients, including
former smokers, were categorized as
nonsmokers. In addition, the frequency
of recall visits following the completion
of the implant-supported restorative
therapy was assessed and categorized as
“regular” if the patient had attended on
an annual basis.
Clinicians involved in the treatment
were categorized with regard to private
or public dental clinical setting and
general practitioner or registered
specialist by the Swedish National
Board of Health and Welfare at the time
of treatment. For surgical treatment,
specialists in oral/maxillofacial surgery
and periodontics were considered, while
prosthetic treatment involved specialists
in prosthodontics, stomatognathic
physiology, and periodontics.
Implants were categorized according
to brand, as defined by implant system
and provider. Implants were also grouped
regarding length (<10 mm and 10 mm),
diameter (<4 mm and 4 mm), and
installation protocols (1-stage and 2-stage).
Bone augmentation procedures, including
ridge and sinus augmentation, and the use
of prophylactic antibiotics were recorded.
Implants were categorized according
to jaw and anterior/posterior position.
Anterior was defined as the region
corresponding to tooth position canine
to canine. Further categorization included
type of prosthetic retention, design
of suprastructure, type of connection,
and prosthetic loading protocols.
Loading was categorized as “early” if the
supraconstruction was connected <4 wk
after implant placement.
Clinical Evaluation
In total, 900 subjects, stratified for age,
were randomly selected from the patient-
file database and subsequently invited to a
free-of-cost examination at a conveniently
located dental clinic in Sweden about
9 y after therapy. The examinations were
carried out by specialists in periodontics,
predominantly by 2 investigators (J.D.
and J.H.), and included clinical and
radiographic assessments of the relevant
implant regions.
Assessment of Implant Loss
If implant loss had occurred prior to
connection of the supraconstruction, it
was scored as an early implant loss. If
the loss had occurred afterward, it was
considered a late implant loss. Early
implant loss was assessed in patient files
by 2 examiners. Double assessments
revealed an inter- and intraexaminer
agreement of 1.0 (Cohen’s unweighted
k). Late implant loss was recorded at the
clinical examination.
Consequences of implant loss
were noted as reported in patient
files. Changes in treatment planning,
placement of new implants, and
noncontinuation of treatment were
recorded for early implant loss. For late
implant loss, placement of new implants,
prosthodontic therapy, and partial or total
loss of reconstructions were scored.
Data Analysis
Recorded data were expressed in
mean values and frequency distributions.
Frequencies of early and late implant
loss were assessed on the implant and
patient level (SPSS 21.0; SPSS, Inc.,
Chicago, IL, USA). To identify factors
affecting the probability of implant loss,
we used multiple logistic multilevel
models (MLwiN 2.28; Center of Multilevel
Modelling, University of Bristol, Bristol,
UK). The hierarchical analyses included
the patient at the higher level and
the implant at the lower level. The
logit function was applied to link the
linear model with the probability of
the binary event. Two models, one for
“early loss” and one for “late loss,” were
built. The independent factors entered
into the models were retrieved from
the patient-file database. For the factor
“implant brand,” 4 groups were formed:
1) Straumann group implants (Basel,
Switzerland), 2) Nobel Biocare group
implants (Zurich, Switzerland), 3) Astra
Tech group implants (Mölndal, Sweden),
and 4) other. Brands representing less
than 5% of all implants were collapsed
into one group to facilitate the statistical
analysis.
at Gothenburg University Library on December 11, 2014 For personal use only. No other uses without permission.jdr.sagepub.comDownloaded from
© International & American Associations for Dental Research 2014
3S
JDR Clinical Research Supplement
vol. XX • issue X • suppl no. X
Models were built with the intercept
as a random term. All variables were
tested by the Wald test in a bivariate
analysis. Significant factors were entered
into a multiple model (fixed effect).
Nonsignificant factors were removed
backward until a final model was created
containing only significant factors (P <
0.05). The intercept for each parameter
was transformed into an odds ratio (OR),
including a 95% confidence interval.
Parameters were estimated using the
Markov chain Monte Carlo method with
50,000 simulations.
Results
Patient Sample
In total, 3,107 subjects gave their
consent for access to patient files, of
which the files of 2,765 patients were
retrieved from more than 800 clinicians.
The patient files covered a mean ± SD
function time of 5.4 ± 2.2 y following
implant therapy. Of 900 invited subjects,
596 attended the clinical examination
(Fig.). Reasons for nonattendance were
lack of interest (187 subjects), general
health (68), unable to contact (30), and
deceased (19). For the patients attending
the clinical examination, a mean ± SD
of 8.9 ± 0.8 y had passed since implant
placement. Attending and nonattending
subjects did not differ significantly in
terms of age, sex, systemic disease, and
therapy-related parameters (e.g., average
number of implants per patient).
Table 1 describes patient-related data in
terms of sex, general and dental health
status, and implant-supported restorative
therapy. Table 2 describes implant-related
data. Three brands (termed Astra Tech,
Nobel Biocare, and Straumann group of
implants) represented 90% of all implants.
Among Astra Tech group implants,
99.2% had a TiOblast surface; 98.7%
of all Nobel Biocare group implants
had a TiUnite surface; and 99.9% of all
Straumann group implants had an SLA
surface. Within the remaining 10% of
“other” implants, the predominant brands
were Biomet 3i (3.3% of all implants;
Palm Beach Gardens, FL, USA), CrescoTi
(1.7%; Kristianstad, Sweden), XiVE (1.3%;
Mannheim, Germany), Frialit (1.3%;
Mannheim, Germany), and Lifecore
(1.2%; Burlington, MA, USA).
Implant Loss
The analysis of patient files (n =
2,765) revealed that 121 subjects (4.4%)
experienced early implant loss with a
total of 154 implants (1.4%) lost (Table 3).
Within this group, 102 patients lost 1, 10
lost 2, 4 lost 3, and 5 lost 4 implants. Of
the 121 subjects affected by early implant
loss, 76 (63%) underwent new implant
placement procedures. Treatment planning
had to be adjusted for 21 (17%). For 2
patients (2%), therapy was not continued
after the early loss had occurred, and for 33
patients (27%), treatment was completed
without renewed implant placement or
changes in treatment planning.
Among the 596 patients examined
clinically, 45 (7.6%) experienced implant
loss, irrespective if it had occurred early
or late. A total of 72 implants (3.0%) were
lost. Twenty-five (4.3%) of the 596 patients
experienced late implant loss, representing
46 implants (2.0%). Within this group,
13 patients lost 1, 8 patients lost 2, and 1
patient lost 3 implants. One patient lost 4
and 2 patients lost 5 implants each. Of the
25 patients affected by late implant loss, 6
(24%) underwent new implant placement
procedures. For 8 patients (32%), new
supraconstructions were produced. For 4
patients (16%), supraconstructions were
modified, while for 5 subjects (20%), the
whole supraconstruction was lost and not
replaced. For 8 cases (32%), late implant
loss had no impact on the prosthetic
rehabilitation.
Early and late implant loss according
to implant brands are described in the
Appendix Table.
Table 4 shows the results of the
multilevel analysis for the event
“early loss.” Of the significant factors
identified in the bivariate analyses, 4
factors showed significantly higher
odds ratios (ORs) for early loss in the
final model: subjects with an initial
diagnosis of periodontitis (OR, 3.3),
smokers (OR, 2.3), implants <10 mm
(OR, 3.8), and implant brand. Compared
with Straumann group implants, Nobel
Biocare group implants (OR, 1.9), Astra
Tech group implants (OR, 2.1), and the
category of “other” implants (OR, 7.8)
presented with significantly higher odds
ratios for early loss.
Data register (SSIA) of patients (age 65-74)
treated with implants in 2003
(n>23000)
Questionnaire sent
(n=3000)
Random selection
Data register (SSIA) of patients (age 45-54)
treated with implants in 2003
(n=1716)
Questionnaire sent
(n=1716)
Questionnaire returned
(n=3827)
Consent: Access to patient files
(n=3107)
Patient files collected
(n=2765)
Invited to clinical examination
(n=900)
Random selection
Attended clinical examination
(n=596)
Assessment:
Early implant loss
Assessment:
Late implant loss
Figure.
Patient enrollment (n = number of patients)
at Gothenburg University Library on December 11, 2014 For personal use only. No other uses without permission.jdr.sagepub.comDownloaded from
© International & American Associations for Dental Research 2014
4S
JDR Clinical Research Supplement Month XXXX
Results of the multilevel analysis for “late
loss” are also described in Table 4. The
final model showed associations between
late loss and implant brand. Straumann
group implants were used as reference
(OR, 1.0). Odds ratios for Nobel Biocare
group implants and Astra Tech group
implants were 6.1 and 5.2, respectively. For
“other” implants (OR, 58.2), a significantly
higher odds ratio was observed.
Discussion
In the present study, early and late
occurring loss of dental implants were
evaluated in a large and randomly selected
patient sample. It was demonstrated that
early implant loss occurred in 4.4% of
patients, while 4.2% of the patients who
were examined around 9 y after therapy
presented with late implant loss. Taken
together, 7.6% of the patients had lost
at least 1 implant. In addition, multilevel
analysis revealed higher odds ratios
for early implant loss among smokers
and patients with an initial diagnosis of
periodontitis. Implants shorter than 10
mm and representing certain brands also
showed higher odds ratios for early implant
loss. Implant brand also influenced late
implant loss. It is suggested that implant
loss is not an uncommon event and that
patient and implant characteristics influence
outcomes.
The present study reports on a patient
material, which in several aspects is
different from that presented in most clinical
studies on dental implant therapy. The
national data register of the SSIA covers
almost all individuals >20 y of age receiving
dental care in public or private setting
in Sweden. As the register also included
patients exposed to restorative therapy
using dental implants, the patient groups
of the present study represent a random
sample of the selected age categories of
the population. In addition, the implant-
supported restorative therapy in the present
study was carried out by a large number
of clinicians representing different clinical
settings and training in the field. Thus,
in contrast to previous publications on
so-called convenience patient samples,
the present study sample constitutes a
true cohort. The evaluation also applies
to everyday clinical practice and provides
data on effectiveness rather than efficacy
(Berglundh and Giannobile 2013).
Patients from 2 age groups were
randomly selected for the present
study. As stated above, in 2003, the
federal subsidies for implant-supported
restorative therapy increased for patients
65 y of age. A reference group of
younger individuals (45–54 y) was also
included in the study (Derks et al. 2014).
Table 1.
Patient-Related Information Retrieved from Patient Files
Patient File
Sample (n = 2,765)
Clinical Examination
Sample (n = 596)
Female sex 54 55
Smoker 30 29
Diabetes 8 5
Myocardial infarction 2 2
Stroke 2 2
Periodontitis diagnosis 24 22
Prophylactic antibiotics at implant placement 86 84
Implants per patient, mean ± SD 4.1 ± 2.9 4.0 ± 2.8
Surgery
General practitioner 22 21
Specialist 78 79
Prosthetics
General practitioner 76 73
Specialist 24 27
Maintenance
General practitioner 82 80
Specialist 14 17
None 4 3
Frequency of recall visits
Regular (annual) 81 82
Irregular 19 18
All data are given in percentages unless otherwise noted.
at Gothenburg University Library on December 11, 2014 For personal use only. No other uses without permission.jdr.sagepub.comDownloaded from
© International & American Associations for Dental Research 2014
5S
JDR Clinical Research Supplement
vol. XX • issue X • suppl no. X
Table 2.
Implant-Related Information Retrieved from Patient Files
Patient File
Sample (n = 11,311
Implants)
Clinical Examination
Sample (n = 2,367
Implants)
Implant brand
Astra Tech group implants (Astra Tech Implant System) 19 19
Nobel Biocare group implants (Brånemark System, Replace Select) 41 40
Straumann group implants (Straumann Dental Implant System) 30 32
Other 10 9
Implant length
<10 mm 9 9
10 mm 91 91
Implant diameter
<4 mm 59 56
4 mm 41 44
Jaw
Maxilla 58 60
Mandible 42 40
Position
Anterior (canine-canine) 45 44
Posterior 55 56
Implant placement
Immediate (same session as tooth extraction) 4 4
Healed ridge 96 96
Installation procedure
1-stage 49 49
2-stage 51 51
Bone augmentation procedure 7 8
Loading
Early/direct (<4 wk from implant placement) 7 5
Late (4 wk) 93 95
Retention of supraconstruction
Screw retained 83 81
Cemented 16 19
Removable 1 0
Design of supraconstruction
Single 10 12
Multiunit without cantilever 30 30
Multiunit with cantilever 60 58
Connection
Single 10 12
Implant-implant 89 87
Implant-tooth 1 1
All data are given in percentages.
at Gothenburg University Library on December 11, 2014 For personal use only. No other uses without permission.jdr.sagepub.comDownloaded from
© International & American Associations for Dental Research 2014
6S
JDR Clinical Research Supplement Month XXXX
The findings on early implant loss
presented in the current study disclosed
that the proportion of affected patients
was larger than that of early lost implants
(4.2% vs. 1.4%). While similar results
were presented in a multicenter study on
implant loss performed in private clinics
(Esposito et al. 2010), results from a study
conducted in a university clinic revealed
that early loss occurred in 0.7% of
implants and 0.8% of patients (Bornstein
et al. 2008).
The approach of a retrospective
evaluation of early implant loss carried
out in the present study was also applied
by Alsaadi et al. (2007). They examined
2,004 patient files from a university clinic
and reported that 258 implants (3.6%)
in 178 patients (8.9%) were lost prior to
or at abutment connection. Most cases
(91%) had lost 1 or 2 implants. While the
Table 3.
Implant Loss
Early Loss (2,765 Patients,
11,311 Implants)
Late Loss (596 Patients, 2,367
Implants, Mean Function
Time: 8.9 y)
Total Loss (596 Patients,
2,367 Implants, Mean
Function Time: 8.9 y)
Patients affected 121 (4.4%)
10 patients unaccounted for
25 (4.2%) 45 (7.6%)a
Implants lost 154 (1.4%)
50 implants unaccounted for
46 (2.0%)b
2 implants unaccounted for
72 (3.0%)
2 implants unaccounted for
aEarly and/or late loss.
bEarly lost implants not considered for calculation of percentage.
Table 4.
Factors Associated with Early and Late Implant Loss: Multiple Multilevel Analysis
Early Loss (11,311 Implants,
2,765 Subjects)
Early Loss (% of
Implants) Odds Ratio
95% Confidence
Interval P Value
Periodontitis diagnosis
No 1.0 1
Yes 2.3 3.29 1.69–6.42 0.001
Smoking
Nonsmoker 0.9 1
Smoker 2.2 2.32 1.03–5.24 0.042
Implant length
 ≥ 10 mm 1.2 1
<10 mm 3.0 3.78 2.15–6.64 <0.001
Implant brand
A 0.7 1
B 1.3 1.94 1.02–3.69 0.043
C 1.5 2.10 1.03–4.30 0.042
D 3.5 7.79 3.69–16.47 <0.001
Late Loss after 8.9 y (2,367
Implants, 596 Subjects)
Late Loss (% of
Implants) Odds Ratio
95% Confidence
Interval P Value
Implant brand
A 0.5 1
B 2.4 6.13 0.47–80.51 0.139
C 2.5 5.23 0.28–99.38 0.244
D 3.8 58.15 2.35–1435.92 0.012
Implant brands: A, Straumann implant group; B, Nobel Biocare implant group; C, Astra Tech implant group; D, other.
at Gothenburg University Library on December 11, 2014 For personal use only. No other uses without permission.jdr.sagepub.comDownloaded from
© International & American Associations for Dental Research 2014
7S
JDR Clinical Research Supplement
vol. XX • issue X • suppl no. X
data presented by Alsaadi et al. (2007)
indicated larger proportions of early lost
implants and affected patients than in
the present study, a similar percentage
of patients presenting with 1 or 2 lost
implants was found in the 2 studies.
The findings on higher odds ratios for
smokers and implants with length
<10 mm for early implant loss reported
by Alsaadi et al. (2007) are consistent
with results in the present study.
The multilevel analysis of implant-
related factors on early implant loss
in the present study showed that, in
addition to implant length, implant
brand influenced the outcome. Thus,
Straumann group implants presented
with a lower odds ratio for early implant
loss than other implant brands. As
the Straumann group implants in the
present material had a 1-piece design
that included both the intraosseous and
transmucosal portions, the installation
procedure for this implant type called
for a nonsubmerged or so-called 1-stage
technique. Other categories of implants,
however, comprised 2 parts and were,
hence, installed using either a 1- or a
2-stage (initially submerged) technique.
The analysis of early implant loss in
the present study failed to demonstrate
significant differences between the 2
installation procedures. Reasons for
the observed differences between
implant brands with regard to early
implant loss are not detectable from
the current material. Factors related to
implant design in combination with
site preparation may be considered, as
early implant loss indicates a failure in
integration of the implant in bone tissue
following implant installation.
The results from the analysis of patient-
related factors in the present study
revealed that an initial diagnosis of
periodontitis had a higher odds ratio for
early implant loss. While periodontitis
is one of the most common diseases in
humans and one of the main reasons
for tooth loss, the susceptibility to the
disease itself may not explain the higher
odds ratio. The consequences of the
progression of the disease, however,
with advanced attachment and bone
loss and, eventually, tooth loss result
in an edentulous ridge with reduced
dimensions. Reduced ridge dimensions
may also reflect the use of implants with
length <10 mm. In this context, it should
be realized that differences in bone
quality of the alveolar process between
patients with and without periodontitis
may not exist as studies on human bone
samples failed to demonstrate differences
between patient groups (Cecchinato
et al. 2012; Lindhe et al. 2012).
The second part of the present
investigation was based on findings
made in a clinical examination
performed on 596 of 900 invited
patients at 9 y after therapy. The rate
of attendance may be considered
high, taking into account the age
of the 2 patient groups (54–63 and
74–83 y, respectively, at the time of
clinical examination) and the varying
accessibility for patients to dental
clinics in this nationwide project. The
examination revealed that 2.0% of
implants in 4.2% of the patients were
lost during the 9 y after prosthesis
connection. These findings indicate
better outcomes in comparison with data
reported in long-term studies in implant
dentistry. Results from a systematic
review revealed a mean total implant
loss rate of 5.1% after 5 y and 6.9% after
10 y (Pjetursson et al. 2012). Most of
the 32 studies included in the review
represented 5-y outcomes, with early
and late implant loss occurring in 2.4%
and 2.7%, respectively. In addition, the
patients in the review by Pjetursson
et al. (2012) represented in most cases
specialist or university clinical settings.
The evaluations made in the present
study on late implant loss did not
disclose any differences in outcomes
between clinical settings (i.e., public vs.
private practice or general practitioner
vs. registered specialist). Furthermore, no
associations between late implant loss
and patients with an initial diagnosis of
periodontitis or presenting with irregular
recall visits were found. This observation
is not in agreement with data reported in
a 10-y study on implant loss in different
categories of patients (Roccuzzo
et al. 2010). In addition, the finding that
smoking was not associated with late
implant loss is not in agreement with
data presented in systematic reviews
(Heitz-Mayfield and Huynh-Ba 2007;
Strietzel et al. 2007).
The multilevel analysis in the present
study disclosed that implant brand also
influenced late implant loss. As was the
case for differences between implant
brands regarding early implant loss, the
data from the present material did not
provide explanations for the differences
in late implant loss. In addition, there
may be several reasons for late implant
loss, such as progressive marginal bone
loss, damages on the interface between
the implant and the bone tissue, or
harm to the implant, including implant
fracture.
The present study also examined the
consequences of early and late occurring
implant loss. The findings indicate that
for the individual patient, implant loss
has a significant effect on the overall
treatment outcome of implant-supported
restorative therapy.
In summary, the present study reported
on outcomes in implant dentistry
assessed in a large and randomly
selected patient sample representing
effectiveness of the treatment
procedures. Almost 8% of patients had
lost 1 implants, and several patient- and
implant-related factors influencing early
and late occurring loss were detected.
Author Contributions
J. Derks, contributed to data analysis,
drafted the manuscript; J. Håkansson,
contributed to conception and design,
critically revised the manuscript;
J.L. Wennström and T. Berglundh,
contributed to conception, design, and
data analysis, drafted the manuscript;
C. Tomasi and M. Larsson, contributed
to data analysis, critically revised the
manuscript. All authors gave final
approval and agree to be accountable for
all aspects of the work.
Acknowledgments
The authors greatly appreciate Dr. Max
Petzold for assistance in the statistical
analysis. The study was supported
at Gothenburg University Library on December 11, 2014 For personal use only. No other uses without permission.jdr.sagepub.comDownloaded from
© International & American Associations for Dental Research 2014
8S
JDR Clinical Research Supplement Month XXXX
by grants from the Swedish Social
Insurance Agency (Försäkringskassan);
the Swedish Research Council (VR:
K2013-52X-22197-01-3); TUA research
Gothenburg, Sweden; and the Swedish
Dental Society. Dr. Berglundh reports
grants and personal fees from Dentsply
Implants IH, outside the submitted
work. Dr. Derks, Dr. Tomasi, and Dr.
Wennström report personal fees from
Dentsply Implants IH, outside the
submitted work. The authors declare no
potential conflicts of interest with respect
to the authorship and/or publication of
this article.
References
Alsaadi G, Quirynen M, Komárek A, Van
Steenberghe D. 2007. Impact of local and
systemic factors on the incidence of oral
implant failures, up to abutment connection.
J Clin Periodontol. 34(7):610–617.
Berglundh T, Giannobile WV. 2013.
Investigational clinical research in implant
dentistry: beyond observational and
descriptive studies. J Dent Res. 92(12
Suppl):107S–108S.
Berglundh T, Persson L, Klinge B. 2002. A
systematic review of the incidence of
biological and technical complications in
implant dentistry reported in prospective
longitudinal studies of at least 5 years. J Clin
Periodontol. 29(Suppl 3):197–212; discussion
232–233.
Bornstein MM, Halbritter S, Harnisch H, Weber
H-P, Buser D. 2008. A retrospective analysis
of patients referred for implant placement
to a specialty clinic: indications, surgical
procedures, and early failures. Int J Oral
Maxillofac Implants. 23(6):1109–
1116.
Cecchinato D, Bressan EA, Toia M, Araújo MG,
Liljenberg B, Lindhe J. 2012. Osseointegration
in periodontitis susceptible individuals. Clin
Oral Impl Res. 23(1):1–4.
Derks J, Håkansson J, Wennström JL, Klinge
B, Berglundh T. 2014. Patient-reported
outcomes of dental implant therapy in a
large randomly selected sample. Clin Oral
Impl Res. Aug 14 (Epub ahead of print; DOI:
10.1111/clr.12464).
Esposito M, Cannizzaro G, Bozzoli P, Checchi
L, Ferri V, Landriani S, Leone M, Todisco M,
Torchio C, Testori T, et al. 2010. Effectiveness
of prophylactic antibiotics at placement of
dental implants: a pragmatic multicentre
placebo-controlled randomised clinical trial.
Eur J Oral Implantol. 3(2):135–143.
Heitz-Mayfield LJ, Huynh-Ba G. 2009. History of
treated periodontitis and smoking as risks
for implant therapy. Int J Oral Maxillofac
Implants. 24(Suppl):39–68.
Jung RE, Zembic A, Pjetursson BE, Zwahlen M,
Thoma DS. 2012. Systematic review of the
survival rate and the incidence of biological,
technical, and aesthetic complications of
single crowns on implants reported in
longitudinal studies with a mean follow-up
of 5 years. Clin Oral Impl Res. 23(Suppl
6):2–21.
Lindhe J, Cecchinato D, Bressan EA, Toia M,
Araújo MG, Liljenberg B. 2012. The alveolar
process of the edentulous maxilla in
periodontitis and non-periodontitis subjects.
Clin Oral Impl Res. 23(1):5–11.
Pjetursson BE, Thoma D, Jung R, Zwahlen M,
Zembic A. 2012. A systematic review of the
survival and complication rates of implant-
supported fixed dental prostheses (FDPs)
after a mean observation period of at least 5
years. Clin Oral Impl Res. 23(Suppl 6):22–38.
Roccuzzo M, De Angelis N, Bonino L, Aglietta
M. 2010. Ten-year results of a three-arm
prospective cohort study on implants in
periodontally compromised patients. Part 1:
implant loss and radiographic bone loss. Clin
Oral Impl Res. 21(5):490–496.
Strietzel FP, Reichart PA, Kale A, Kulkarni
M, Wegner B, Küchler I. 2007. Smoking
interferes with the prognosis of dental
implant treatment: a systematic review
and meta-analysis. J Clin Periodontol.
34(6):523–544.
Tomasi C, Derks J. 2012. Clinical research of
peri-implant diseases—quality of reporting,
case definitions and methods to study
incidence, prevalence and risk factors of
peri-implant diseases. J Clin Periodontol.
39(Suppl 12):207–223.
Tonetti M, Palmer R; Working Group 2 of the
VIII European Workshop on Periodontology.
2012. Clinical research in implant dentistry:
study design, reporting and outcome
measurements: consensus report of Working
Group 2 of the VIII European Workshop on
Periodontology. J Clin Periodontol. 39(Suppl
12):73–80.
at Gothenburg University Library on December 11, 2014 For personal use only. No other uses without permission.jdr.sagepub.comDownloaded from
© International & American Associations for Dental Research 2014
... Dental implants represent a highly successful treatment option for restoring the edentulous arch [1]. The precise positioning and angulation of dental implants play a critical role in ensuring their long-term stability. ...
Article
Full-text available
Purpose: This study evaluated the accuracy of implant placement using a robotic system (Remebot) compared to freehand surgery and explored factors influencing accuracy. Methods: This retrospective study included 95 implants placed in 65 patients, divided into robot-assisted (50 implants) and freehand (45 implants) groups. Platform, apical, and angular deviations were measured by superimposing preoperative plans and the postoperative CBCT images. Mean deviations between groups were compared, and regression analysis assessed the impact of implant dimensions and positioning on accuracy. Results: The robot-assisted group exhibited significantly lower mean deviations in platform (0.44 ± 0.17 mm), apical (0.46 ± 0.17 mm), and angular deviations (0.85 ± 0.47°) compared to the freehand group (1.38 ± 0.77 mm, 1.77 ± 0.82 mm, and 6.63 ± 3.90°, respectively; p < 0.001). Regression analysis indicated no significant impact of implant location, jaw type, or implant dimensions on the robotic system’s accuracy, unlike the freehand placement where these factors influenced deviations. Conclusions: Robot-assisted implant surgery significantly enhances accuracy and clinical safety compared to freehand techniques. Despite limitations, robotic surgery presents a promising advancement in implant dentistry by reducing human error.
... No geral, o risco parece ser relativamente baixo e muitos especialistas concordam que os benefícios do tratamento com bifosfonatos superam os seus riscos potenciais. 17,18,19 Uma metanálise mostrou que a ingestão de bifosfonatos orais em baixas doses para tratamento da osteoporose, em geral, não compromete a terapia com implantes. 20 No entanto, os pacientes que recebem medicamentos antirreabsortivos intravenosos apresentam risco aumentado de OMRM. ...
Article
Full-text available
Objetivo: O objetivo desta revisão sistemática foi analisar a associação de medicamentos antirreabsortivos e a ocorrência de falhas na reabilitação com implantes dentários. Materiais e Métodos: A presente revisão sistemática foi elaborada de acordo com as normas PRISMA utilizando-se a base de dados PubMED/MEDLINE. Dois avaliadores pesquisaram artigos em língua inglesa com acesso livre, publicados entre 2012 e 2023 (inclusive) que tratavam da questão PICO. Foram incluídos estudos em que os pacientes usuários de drogas antirreabsortivas tivessem sido submetidos à cirurgia de implantes dentários. Ainda, casos-controle, séries de casos, estudos observacionais retrospectivos e prospetivos foram incluídos na pesquisa. Resultados: Inicialmente foi obtido um total de 39 artigos na base de dados, após a remoção de estudos duplicados e os que não se incluíam nos critérios de inclusão/exclusão restaram 21 artigos. Após leitura do título e resumo foram obtidos 5 artigos para leitura integral e avaliação da elegibilidade. Por fim, foram incluídos 4 artigos nesta revisão sistemática. Esta revisão sistemática analisou 163 pacientes com histórico de uso de antirreabsortivos (128 mulheres e 35 homens). Nos estudos avaliados 34 implantes foram perdidos. A idade dos pacientes variou de 54 a 87 anos. A terapia antirreabsortiva utilizada entre os pacientes incluiu: Alendronato, Zoledronato, Alendronato + Denosumabe, Ibandronato e Pamidronato. A maioria das lesões localizava-se predominantemente nas áreas posteriores. O período de acompanhamento variou de 12 a 60 meses. Conclusão: Considerando as limitações encontradas neste estudo, observou-se um maior risco de falha nos implantes em pacientes sob terapia antirreabsortiva intravenosa e presença de comorbidades associadas. Para obter evidências mais conclusivas, futuros estudos prospectivos randomizados com maior tempo de acompanhamento devem ser realizados para avaliar com precisão o impacto destes medicamentos no sucesso do tratamento com implantes.
... Early implant failures, often linked to operational trauma or contamination, differ from late failures, which typically arise from biological or mechanical issues, including peri-implantitis and excessive occlusal load (Derks et al. 2015). The likelihood of implant failure can be influenced by patient-related factors such as smoking, dietary preferences, history of periodontitis, systemic health and bone quality, as well as operator-related factors such as experience, implant geometry and restoration type (Dreyer et al. 2018; J. J. Kim et al. 2020;Roccuzzo et al. 2022;Serroni et al. 2024;Yoon et al. 2011). ...
Article
Full-text available
Aim This nationwide population‐based cohort study aimed to assess the incidence of implant complication treatments, including implant removal procedures and peri‐implantitis treatments, in relation to implant surfaces and abutment types. Methods Data from the National Health Insurance Service, covering approximately 50 million individuals, were used. Implants and abutments were categorized by codes, including surfaces such as resorbable blasting media, sandblasted large grit and acid‐etched (SA) and hydroxyapatite coating, along with abutment structures (one‐piece straight, two‐piece straight, angled). The incidence of implant complication treatments was analysed using Kaplan–Meier curves and Cox proportional hazards regression ( α = 0.05). Results The study included 2,354,706 implants. The SA group had the lowest hazard ratio for implant removal procedures ( p < 0.0001). No significant differences were found in the risk of peri‐implantitis treatments between implant surfaces ( p = 0.0587). The risk of implant complication treatments did not differ significantly by the abutment type ( p = 0.9542). The incidence rate of implant complication treatments was < 3.9 per 1000 implant‐years across all groups. Conclusions The SA group showed a slightly lower risk of late implant loss, whereas no significant association was found for the abutment type groups. All implant and abutment type groups showed an incidence rate of < 3.9 per 1000 implant‐years for complication treatments.
Article
Full-text available
Objective: To determine the awareness levels of dentists about possible risk factors in order to prevent early implant losses. Methods: The questionnaire form was directed to the participants online. Statistical analyzes were made with frequency analysis and Chi-square test. Results: Majority of the participants usually (68.4%) prescribe amoxicillin (postoperatively 1 g 2x1) to patients in implant surgeries. While the rate of those who thought that prophylactic antibiotic therapy was mostly and always effective in preventing early implant loss was 17.6%, this rate was 42.7% for postoperative antibiotherapy applications. The highest rate of thinking that prophylactic antibiotherapy is effective in preventing early implant loss was found in the periodontology specialist (20.5%) group. Periodontology specialists (23.3%) were the group who thought that the effectiveness of postoperative antibiotherapy was the least in this regard. History of periodontitis (76.3%) and postoperative complication development (73.1%), diabetes (92.4%), smoking (89.8%) and osteoporosis (78.7%) were evaluated as the factors that have the most impact on early implant loss. Conclusion: It is thought that the general knowledge level of the dentists participating in the survey about early implant loss is sufficient. We believe that it would be beneficial to organize postgraduate vocational training programs in order to eliminate the differences between the knowledge levels of dentists. Key Words: Awarenes Level, Early Implant Failure, Implant Complications
Article
Aim To evaluate long‐term survival and success of dental implants and evaluate indicators affecting the long‐term outcome. Materials and Methods Implant survival, success and crestal bone loss (BL) over time were evaluated. For covariates at patient level, Kaplan–Meier estimates of implant survival were compared between groups with the log‐rank test. Observed mean bone loss (MBL) was plotted as a function of time. Cumulative frequencies of BL were plotted for different post‐op times. Uni‐ and multivariate analysis was performed. Simple linear mixed and multiple linear mixed models for BL at 1, 5 and 10 years were fitted. Results 407 patients (221 women, 186 men; mean age 64.86 years (range 28–92, SD 10.11)), with 1482 implants, responded. Absolute implant survival was 94.74%; MBL was 0.81 mm (SD 1.58, range 0.00–17.00) after an average follow‐up of 10.66 years (range 10–14, SD 0.87). Implant survival was influenced on implant level by smoking, implant width and early bone loss (EBL) > 0.5 mm; on patient level by a history of periodontitis. Indicators influencing MBL after the 1st year were abutment height, type of surgery and implant width, while after 5 and 10 years of function were abutment height, EBL > 0.5 mm and smoking. Conclusion Implant survival was significantly affected by a history of periodontitis on patient level and by smoking, implant width and EBL > 0.5 mm on implant level. Late bone loss was significantly affected by abutment height, EBL > 0.5 mm and smoking. Trial Registration: B670201524796
Article
Full-text available
To evaluate the efficacy of prophylactic antibiotics for dental implant placement. Thirteen dentists working in private practices agreed to participate in this trial, each centre providing 50 patients. One hour prior to implant placement, patients were randomised to take orally 2 g amoxicillin or identical placebo tablets. Patients needing bone augmentation at implant placement were not included. Outcome measures were prosthesis and implant failures, adverse events and post-operative complications. Patients were seen 1 week, 2 weeks and 4 months post-operatively. Two centres did not deliver any data, two centres did not manage to include the agreed quota of patients and three patients had to be excluded. Two-hundred and fifty-two patients were evaluated in the antibiotic group and 254 in the placebo group, and none dropped out at 4 months. Four prostheses and seven implants (in five patients) failed in the antibiotics group versus 10 prostheses and 13 implants (in 12 patients) in the placebo group. Eleven complications were reported in the antibiotic group versus 13 (in 12 patients) in the placebo group. No side effects were reported. There were no statistically significant differences for prosthesis failures, implant losses and complications. Patients receiving immediate post-extractive implants had an increased failure risk compared with patients receiving delayed implants (9% versus 2%). No statistically significant differences were observed, although trends clearly favoured the antibiotic group. Immediate post-extractive implants were more likely to fail.
Article
Background In addition to traditional clinical parameters, the need to include patient-reported assessments into dental implant research has been emphasized.AimThe aim of this study was to evaluate patient-reported outcomes following implant-supported restorative therapy in a randomly selected patient sample.Material and Methods Four thousand seven hundred and sixteen patients were randomly selected from the data register of the Swedish Social Insurance Agency. A questionnaire containing 10 questions related to implant-supported restorative therapy was mailed to each of the individuals about 6 years after therapy. Associations between questionnaire data, and (i) patient-related, (ii) clinician-related and (iii) therapy-related variables were identified by multivariate analyses.ResultsThree thousand eight hundred and twenty-seven patients (81%) responded to the questionnaire. It was demonstrated that the overall satisfaction among patients was high. Older patients presented with an overall more positive perception of the results of the therapy than younger patients and males were more frequently satisfied in terms of esthetics than females. While clinical setting did not influence results, patients treated by specialist dentists as opposed to general practitioners reported a higher frequency of esthetic satisfaction and improved chewing ability. In addition, patients who had received extensive implant-supported reconstructions, in contrast to those with small reconstructive units, reported more frequently on improved chewing ability and self-confidence but also to a larger extent on implant-related complications.Conclusion It is suggested that patient-perceived outcomes of implant-supported restorative therapy are related to (i) age and gender of the patient, (ii) the extent of restorative therapy and (iii) the clinician performing the treatment.
Article
The objective of this systematic review was to assess the 5- and 10-year survival of implant-supported fixed dental prostheses (FDPs) and to describe the incidence of biological and technical complications. An electronic Medline search complemented by manual searching was conducted to identify prospective and retrospective cohort studies and case series on FDPs with a mean follow-up time of at least 5 years. Patients had to have been examined clinically at the follow-up visit. Failure and complication rates were analyzed using standard and random-effects Poisson regression models to obtain summary estimates of 5-year and 10-year survival and complication rates. The updated search provided 979 titles and 257 abstracts. Full-text analysis was performed for 90 articles resulting in a total 32 studies that met the inclusion criteria. Meta-analysis of these studies indicated an estimated survival of implants supporting FDPs of 95.6% after 5 years and 93.1% after 10 years. When machined surface implants were excluded from the analysis and only rough surface implants included, the survival rate increased to 97.2% after 5 years. The survival rate of implant-supported FDPs was 95.4% after 5 years and 80.1% after 10 years of function. When the analysis was done exclusively for metal-ceramic FDPs, hence the old gold-acrylic FDPs were excluded, the survival rate increased significantly. The survival rate of metal-ceramic implant-supported FDPs was 96.4% after 5 years and 93.9% after 10 years. Only 66.4% of the patients were free of any complications after 5 years. The most frequent complications over the 5-year observation period were fractures of the veneering material (13.5%), peri-implantitis and soft tissue complications (8.5%), loss of access hole restoration (5.4%), abutment or screw loosening (5.3%), and loss of retention of cemented FDPs (4.7%). It may be concluded that implant-supported fixed dental prostheses (FDPs) are a safe and predictable treatment method with high survival rates. However, biological and technical complications were frequent (33.6%). To minimize the incidence of complications, dental professionals should make great effort in choosing reliable components and materials for implant-supported FDPs and the patients should be placed in well-structured maintenance system after treatment.
Article
To assess the 5-year survival of implant-supported single crowns (SCs) and to describe the incidence of biological, technical, and aesthetic complications. The focused question was: What is the survival rate of implants supporting single crowns and implant-supported crowns with a mean follow-up of 5 years and to which extent do biological, technical, and aesthetic complications occur? A Medline search (2006-2011) was performed for clinical studies focusing on implant-supported SCs with a mean follow-up of at least 5 years. The search was complemented by an additional hand search and the inclusion of 24 studies from a previous systematic review (Jung et al. 2008a). Survival and complication rates were analyzed using random-effects Poisson's regression models to obtain summary estimates of 5- and 10-year proportions. Forty-six studies derived from an initial search count of 1083 titles and the complementary publications from the previous systematic review (Jung et al. 2008a) were selected and the data were extracted. Based on the meta-analysis, survival of implants supporting SCs at 5 years amounted to 97.2% (95% CI: 96.3-97.9%), and at 10 years amounted to 95.2% (95% CI: 91.8-97.2%). The survival of implant-supported SCs was 96.3% (95% CI: 94.2-97.6%) after 5 years and 89.4% (95% CI: 82.8-93.6%) after 10 years. For biological complications, a 5-year cumulative soft tissue complication rate of 7.1% (95% CI: 4.4-11.3%) and a cumulative complication rate for implants with bone loss >2 mm of 5.2% (95% CI: 3.1-8.6%) were calculated. Technical complications reached a cumulative incidence of 8.8% (95% CI: 5.1-15.0%) for screw-loosening, 4.1% (95% CI: 2.2-7.5%) for loss of retention, and 3.5% (95% CI: 2.4-5.2%) for fracture of the veneering material after 5 years. The cumulative 5-year aesthetic complication rate amounted to 7.1% (95% CI: 3.6-13.6%). The outcomes of the meta-analysis demonstrated high implant survival rates for both the single tooth implants and the respective single crowns after 5 and 10 years. However, technical, biological, and aesthetic complications were frequent.
Article
The objective of this working group was to assess and make specific recommendations to improve the quality of reporting of clinical research in implant dentistry and discuss ways to reach a consensus on choice of outcomes. Discussions were informed by three systematic reviews on quality of reporting of observational studies (case series, case-control and cohort) and experimental research (randomized clinical trials). An additional systematic review provided information on choice of outcomes and analytical methods. In addition, an open survey among all workshop participants was utilized to capture a consensus view on the limits of currently used survival and success-based outcomes as well as to identify domains that need to be captured by future outcome systems. The Workshop attempted to clarify the characteristics and the value in dental implant research of different study designs. In most areas, measurable quality improvements over time were identified. The Workshop recognized important aspects that require continued attention by clinical researchers, funding agencies and peer reviewers to decrease potential bias. With regard to choice of outcomes, the limitations of currently used systems were recognized. Three broad outcome domains that need to be captured by future research were identified: (i) patient reported outcome measures, (ii) peri-implant tissue health and (iii) performance of implant supported restorations. Peri-implant tissue health can be measured by marginal bone level changes and soft tissue inflammation and can be incorporated in time to event analyses. The Workshop recommended that collaboration between clinicians and epidemiologists/clinical trials specialists should be encouraged. Aspects of design aimed at limitation of potential bias should receive attention by clinical researchers, funding agencies and journal editors. Adherence to appropriate reporting guidelines such as STROBE and CONSORT are necessary standards. Research on outcome measure domains is an area of top priority and should urgently inform a proper process leading to a consensus on outcome measures in dental implant research.
Article
To review the quality of reporting and the methodology of clinical research on the incidence, prevalence and risk factors of peri-implant diseases. A MEDLINE search was conducted for cross-sectional, case-control and prospective longitudinal studies reporting on peri-implant diseases. To evaluate the quality of reporting of the selected studies the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) checklist was utilized. The search provided 306 titles and abstracts, out of which 40 were selected for full-text analysis. Finally, 16 studies were included out of which five assessed prevalence and only two the incidence of peri-implant diseases. 13 articles studied risk indicators for peri-implant diseases. None of the scrutinized articles adhered fully to the STROBE criteria. The large majority of articles did not (i) clearly state the applied study design, (ii) describe any effort to address potential sources of bias, (iii) explain how missing data were addressed, (iv) perform any kind of sensitivity analysis, (v) indicate the number of participants with missing data for each variable of interest. Collectively, the findings of this review indicate a need for improved reporting of epidemiological studies on peri-implant diseases.
Article
The aim of the present study was to examine tissue integration of implants placed (i) in subjects who had lost teeth because of advanced periodontal disease or for other reasons, (ii) in the posterior maxilla exhibiting varying amounts of mineralized bone. Thirty-six subjects were enrolled; 19 had lost teeth because of advanced periodontitis (group P) while the remaining 17 subjects had suffered tooth loss from other reasons (group NP). As part of site preparation for implant placement, a 3 mm trephine drill was used to remove one or more 2 mm wide and 5-6 mm long block of hard tissue [biopsy site; Lindhe et al. (2011). Clinical of Oral Implants Research, DOI: 10.1111/j.1600-0501.2011.02205.x]. Lateral to the biopsy site a twist drill (diameter 2 mm) was used to prepare the hard tissue in the posterior maxilla for the placement of a screw-shaped, self-tapping micro-implant (implant site). The implants used were 5 mm long, had a diameter of 2.2 mm. After 3 months of healing, the micro-implants with surrounding hard tissue cores were retrieved using a trephine drill. The tissue was processed for ground sectioning. The blocks were cut parallel to the long axis of the implant and reduced to a thickness of about 20 μm and stained in toluidine blue. The percentage of (i) implant surface that was in contact with mineralized bone as well as (ii) the amount of bone present within the threads of the micro-implants (percentage bone area) was determined. Healing including hard tissue formation around implants placed in the posterior maxilla was similar in periodontitis susceptible and non-susceptible subjects. Thus, the degree of bone-to-implant contact (about 59%) as well as the amount of mineralized bone within threads of the micro-implant (about 45-50%) was similar in the two groups of subjects. Pearson's coefficient disclosed that there was a weak negative correlation (-0.49; P < 0.05) between volume of fibrous tissue (biopsy sites) and the length of bone to implant contact (BIC) while there was a weak positive correlation (0.51; P < 0.05) between the volume of bone marrow and BIC.
Article
The aim of this review was to evaluate a history of treated periodontitis and smoking, both alone and combined, as risk factors for adverse dental implant outcomes. A literature search of MEDLINE (Ovid) and EMBASE from January 1, 1966, to June 30, 2008, was performed, and the outcome variables implant survival, implant success, occurrence of peri-implantitis and marginal bone loss were evaluated. Considerable heterogeneity in study design was found, and few studies accounted for confounding variables. For patients with a history of treated periodontitis, the majority of studies reported implant survival rates > 90%. Three cohort studies showed a higher risk of peri-implantitis in patients with a history of treated periodontitis compared with those without a history of periodontitis (reported odds ratios from 3.1 to 4.7). In three of four systematic reviews, smoking was found to be a significant risk for adverse implant outcome. While the majority of studies reported implant survival rates ranging from 80% to 96% in smokers, most studies found statistically significantly lower survival rates than for nonsmokers. There is an increased risk of peri-implantitis in smokers compared with nonsmokers (reported odds ratios from 3.6 to 4.6). The combination of a history of treated periodontitis and smoking increases the risk of implant failure and peri-implant bone loss.
Article
Early implant failures may document that the bone tissue or the wound-healing process following installation surgery was compromised. Subjects who have lost teeth for periodontal reasons exhibit more earlier implant failures than subjects who had experienced tooth loss for other reasons. To describe the tissue of the fully healed extraction sites in subjects who had lost teeth as a result of periodontitis or for other reasons. Thirty-six otherwise healthy, partially dentate subjects with fully healed edentulous portions in the posterior maxilla were included. Nineteen of these subjects had lost teeth because of advanced periodontitis (group P) and 17 for other reasons (group NP). Using a trephine drill, a 4-6 mm long hard tissue specimen was harvested. The biopsies were decalcified, embedded in paraffin, sectioned, stained and examined. The edentulous posterior maxilla was comprised of 47.1 ± 11% lamellar bone, 8.1 ± 7.1% woven bone, 4.3 ± 3.1% osteoid and 16.5 ± 10.4% bone marrow. There were no significant differences in the tissue composition of post-extraction sites of (i) P and NP subjects and (ii) premolar and molar sites. More than 50% of the edentulous maxilla was comprised of mineralized bone (lamellar and woven bone). The bone trabeculae frequently appeared to have a random orientation. The direction of the trabeculae rather than the lack of mineralized bone tissue may explain the clinical impression that the bone in the posterior maxilla provides limited resistance to mechanical instrumentation.