8/17/2019 Mertens, 8 Años Hibrida (1)
1/10
Implant-supported fixed prostheses inthe edentulous maxilla: 8-yearprospective results
Christian MertensHelmut G. Steveling
Authors’ affiliations:Christian Mertens, Helmut G. Steveling, Departmentof Oral and Maxillofacial Surgery, University ofHeidelberg, Heidelberg, Germany
Corresponding author:Dr Christian Mertens
Department of Oral and Maxillofacial SurgeryUniversity of HeidelbergIm Neuenheimer Feld 40069120 HeidelbergGermanyTel.: þ 49 6221 56 39705Fax: þ 49 6221 56 4222e-mail: [email protected]
Key words: dental implants, edentulous maxilla, fixed prostheses, long-term follow-up, impla
survival, marginal bone loss
Abstract
Objective: The purpose of this prospective study was to evaluate the long-term survival and succe
rates of implants and screw-retained, full-arch prostheses placed in edentulous maxillae over 8 years
function.
Materials and methods: A total of 106 Astra Tech implants were placed in the maxillae of 17
edentulous patients in a one-stage surgical approach. After a healing period of 6 months, the patien
received fixed screw-retained bridges. Follow-up visits, including clinical and radiographic
examinations, were performed after 6 months and at yearly intervals. Implant survival, implant
success, and marginal bone-level changes were defined as the primary outcome variables. The
secondary aims were to report periodontal pathogens at 5 years’ follow-up and patients’ satisfactio
at the 8-year follow-up.
Results: The overall observation time was 8 years. One patient died during the study and one impla
failed during the healing period, yielding an 8-year cumulative implant survival rate of 99%. The
prosthetic survival rate was 100%. The mean crestal bone loss amounted to 0.3 0.72mm. Patien
subjective evaluations demonstrated an overall high level of satisfaction. In all cases, except for on
microbiologic probing of the peri-implant sulcus after 5 years showed no higher incidence of
periodontal pathogens.
Conclusions: Screw-retained, full-arch restorations on six implants in an edentulous maxilla are a
predictable and highly successful treatment concept as observed throughout this study with an
observation period of 8 years of function, in particular with respect to low crestal bone loss and hig
patient satisfaction.
Introduction and objective
A lower density frequently characterizes maxil-
lary bone, as opposed to mandibular bone. The
anatomic and morphologic structure of the max-
illa and the reduced bone volume caused by a
high degree of alveolar ridge resorption are con-
sidered to be critical to the success of dental
implants. The literature shows that maxillary
implants are generally less successful than those
in the mandible (Esposito et al. 1998). Implant-
retained maxillary overdentures seem to be af-
fected most frequently, and they show higher
failure rates, as well as greater marginal bone
loss, compared with mandibular implants. In a 3-
year follow-up report by Hutton et al. (1995), the
implant failure rate in cases of mandibular im-
plant-supported overdentures was 3.3%, whereas
it was 27.6% for maxillary overdentures.
Schwartz-Arad et al. (2005) reported a 10-year
implant survival rate for removable maxillary
implants of 83.5%, while the success rate w
only 41.9% when using the Albrektsson et
(1986) success criteria.
On the contrary, fixed prostheses in the maxi
are more successful than removable dentures. P
spective long-termstudies presentimplantsurvi
rates ranging from 95.5% to 97.9% when evalu
ing fixed full-arch bridges in the maxilla.(Bergkv
et al. 2004; Rasmusson et al. 2005; Fischer et
2008). Gallucci et al. (2009) have concluded th
fixed-implant prostheses in the edentulous maxi
are a scientifically validated treatment optio
Offsetting their high survival rates, phonetic pr
blems have been reported frequently for implan
supported maxillary fixed bridges, resulting in lo
patient satisfaction (Lundqvist et al. 1992a, 1992
Heydecke et al. 2004). The gap between muco
and fixed prostheses is thought to be a major cau
of speech difficulties (Lundqvist et al. 1992
Minimizing this gap, however, leads to impa
ment of hygienic procedures.
Date:Accepted 21 June 2010
To cite this article:
Mertens C, Steveling HG. Implant-supported fixedprostheses in the edentulous maxilla: 8-year prospectiveresults.Clin. Oral Impl. Res. 22, 2011; 464–472.doi: 10.1111/j.1600-0501.2010.02028.x
464 c 2010 John Wiley & Sons A
8/17/2019 Mertens, 8 Años Hibrida (1)
2/10
The aim of this study was to investigate
whether appropriately designed, screw-retained,
full-arch prostheses retained by six to eight im-
plants are a feasible treatment option for the
edentulous maxilla.
To ensure complete assessment of this pros-
thetic design, not only implant and prosthetic
survival but additional parameters were also
evaluated during the observation period. The
primary objectives were implant survival as
well as marginal bone-level changes and implant
success, according to the Albrektsson success
criteria. The secondary outcome objectives were
patient satisfaction for assessment of all func-
tional aspects, such as phonetics. Plaque accu-
mulation and soft tissue reactions were measured
at every follow-up to evaluate the clinical para-
meters and the success of patients’ hygienic
procedures, because fixed restorations may be
difficult to clean. Additionally, microbiologic
probing of the peri-implant sulcus was performed
to determine a possible higher incidence of perio-
dontal pathogens and whether any specific mi-
crobiota composition could be identified. All
technical complications were recorded as well.
Patients included in this prospective clinical
trial were followed up over a period of 8 years,
and data were statistically evaluated because
long-term observations in prospective studies
can help validate the predictability of this treat-
ment modality.
Material and methods
Patient selection
The study protocol was approved by the ethics
committee for clinical studies of the Medical
Faculty, University of Heidelberg.
To be included in the study, patients had to
meet the following criteria: 18–75 years of age,
edentulous maxilla, and sufficient bone to sup-
port implants at least 9 mm in length. The
exclusion criteria were as follows: (1) need for
bone augmentation, (2) simultaneous tooth ex-
traction and implant placement, (3) Class 4 bone
quality according to the Lekholm & Zarb classi-
fication (1985; assessed by the surgeon during
fixture installation), (4) any systemic disease or
condition that could compromise postoperative
healing or osseointegration, and (5) taking sys-
temic corticosteroids or any other medication
that could compromise postoperative healing or
osseointegration. Smokers, bruxers, and patients
with poor oral hygiene were not excluded from
this study.
Each patient was thoroughly informed about
the study, and each signed an informed consent
form before entering the study. All patients were
treated between January and October 1999 in the
Department of Oral and Maxillofacial Surgery of
the Heidelberg University by the same experi-
enced clinician.
Surgical procedure
After clinical and radiographical examination
(including intraoral and panoramic radiography)
and verification that the patient fulfilled the
inclusion criteria and that none of the exclusion
criteria applied, he or she was scheduled for
implant surgery. All patients had been edentu-
lous in the maxilla for 6 months or longer. No
simultaneous tooth extractions were performed
during implant surgery.
All patients received prophylactic antibiotics
1 h before surgery, which was performed under
local anaesthesia. After crestal incision and eleva-
tion of a full-thickness muco-periosteal flap, six to
eight implants were placed using a standardized
surgical procedure. The number and location of
implants depended on the anatomic and morpho-
logic conditions of the bone. Implants were evenly
distributed in the anterior and posterior segments
of the edentulous maxilla, depending on the size,
curvature, and shape of the ridge. No surgical
templates were used. Inclination of the implants
was adapted to the opposing dentition. The quan-
tity and quality of the alveolar bone were assessed
during surgery according to the index described by
Lekholm and Zarb (1985). Insertion depth of the
implant was determined by the surrounding bone
to ensure that the implant neck and the alveolar
ridge were at the same level.
The implants (TiOblastt, Astra Tech AB,
Mölndal, Sweden) were moderately rough tita-
nium, screw shaped, and parallel walled. The
fixtures had a coronal portion equipped with
minute threads (MicroThreadt, Astra Tech
AB). Only implants of 3.5 and 4 mm diameter
and having a length of 9–15 mm were used,
depending on the bone dimensions. The implants
were placed using a one-stage surgical procedure.
After connection of healing abutments (Healing
Abutment Zebrat, Astra Tech AB), the flap was
closed and sutured. No postoperative antibiotics
were prescribed. The sutures were removed 7
days after the operation. Throughout this period,
mouth rinsing with chlorhexidine was pre-
scribed. Patients were not allowed to use their
existing complete upper denture until suture
removal. At that time, any pressure from the
denture base on the healing abutments was
relieved, and a resilient relining material was
applied to the base.
Prosthetic procedure
Prosthetic rehabilitation began after a healing
period of 6 months. The healing abutments
were removed and replaced by permanent, on
piece titanium abutments (Uni-Abutmentt, A
tra Tech AB), which were connected using
insertion torque of 20 Newton-centimet
(N cm), according to the manufacturer’s guid
lines. Abutment height was selected clinical
taking into account the mucosal thickness a
interocclusal space. After abutment connectio
impressions were taken using an individual op
tray, screw-retained transfer copings, and a po
ether impression material (Impregums
, 3
ESPE, Seefeld, Germany). Subsequently,
screw-retained registration of jaw relations
centric occlusion was taken. Fitting of the com
plete functional wax-up with assessment of o
clusion, phonetics, and aesthetic parameters a
fitting of the cast framework were perform
during the next appointment. The framewo
needed to fit passively without tension. Canti
vers were not to exceed 10 mm distal to t
position of the most distal implant. As occlus
concepts, either a bilateral balanced occlusion
canine guidance was applied, depending on t
opposing dentures. Finally, the permanent, on
piece, fixed reconstruction was manufactur
To allow for optimal oral hygiene, the relatio
ship between the gingival mucosa and the base
the bridge was evaluated. To avoid muco
irritations by impaired cleaning, the base of t
full-arch restoration was provided with a conve
bridge-like design, slightly contacting the o
mucosa. Concavities of the base should be com
pletely avoided (Figs 1–3). Additionally, the a
rylic base had to be free from porosities and sho
well-polished surfaces. After the denture w
screwed onto the abutments, the openings
Fig. 1 and 2. To avoid mucosal irritations by impai
cleaning, the acrylic base should have a convex surf
design.
Mertens & Steveling Implant-supported fixed prostheses in the edentulous max
c 2010 John Wiley & Sons A/S 465 | Clin. Oral Impl. Res. 22, 2011 / 464–4
8/17/2019 Mertens, 8 Años Hibrida (1)
3/10
the screw holes were sealed with composite.
Hygiene instructions, including the use of in-
terdental brushes and floss, were given to all
patients.
Follow-up protocol
After delivery of the bridge, follow-up visits were
scheduled after 6 months, 12 months, and at
yearly intervals thereafter.
During the follow-ups, the following clinical
parameters were evaluated in accordance with
Mombelli et al. (1987):
Assessment of plaque accumulation – Modi-
fied Plaque Index:
Score 0: no detection of plaque;
Score 1: plaque recognized only by running a
probe across a smooth marginal surface of the
implant;Score 2: plaque can be seen at a glance;
Score 3: abundance of soft matter.
Assessment of bleeding – Modified Bleeding
Index:
Score 0: no bleeding when the periodontal
probe is passed along the gingival margin
adjacent to the implant;
Score 1: isolated bleeding spots visible;
Score 2: blood forms a confluent red line on
the margin;
Score 3: heavy or profuse bleeding.
Both bleeding and plaque accumulation were
obtained on the buccal, lingual, mesial, and distal
surfaces and were calculated per implant as one
unit. The bridges were not routinely removed at
the follow-ups. Only the 60-month follow-up
included completely unscrewing the denture to
test the implants for mobility (Fig. 4). A non-
mobile implant had to resist torquing of the
abutment to 20 N cm. Any implant mobility or
painful response was defined as implant failure.
Additionally, microbiologic probing of the peri-
implant sulcus was performed (ParoChecks
I Kit,
Lambda GmbH, Freistadt, Austria). Pooled sub-
gingival plaque samples were collected from all
implants of each individual patient. To avoid
contamination, samples were not taken before
supragingival plaque removal and isolation of the
area with cotton rolls. Around each abutment,
samples were obtained using two sterile paper
points, which were inserted into the sulcus until
resistance was met and left there for 15 s. All tips
used for one patient were transferred into a single
transport container.
The purpose of this test was to investigate
the composition of the microbiota of the peri-
implant sulcus in edentulous patients wearing
fixed restorations for many years. Because fixed
restorations are often suspected of having exces-
sive plaque accumulation owing to impaired
cleaning, the goal was to determine whether
there was a higher incidence of periodontal patho-
gens and whether any specific pattern could be
identified.
Radiographic examination
In addition to clinical assessments, radiographic
examinations were performed after implant sur-
gery, at prosthetic loading (radiographic baseline),
and at follow-up visits, which began 6 months
after prosthetic loading and then at yearly inter-
vals. The distance between the implant shoulder
and the first visible bone–implant contact was
measured (in mm) at the mesial and distal aspect
of each implant using periapical radiographs ta-
ken using the long-cone technique. (Arvidson
et al. 1998; De Bruyn et al. 2008). To correct
dimensional distortion, the apparent dimension
of each implant was measured on the radiograph
and compared with the actual implant size. To
ensure reproducibility between examinations,
radiographs were taken with the parallel techni-
que using film holders. Care was exercised to
ensure that threads on both the mesial and distal
sides of the implants were clearly imaged (Bergk-
vist et al. 2004; Fischer et al. 2008). All radio-
graphs were analysed by the same examiner, who
had not previously been actively involved in this
study. For evaluations and measurements, the X-
rays were digitalized and analysed using the
computer program Friacom Dental Office V
sion 2.5 (Friadent, Mannheim, Germany).
Statistical method
Data were evaluated using SPSS (SPSS In
Chigaco, IL, USA) and SAS Software (SAS, H
delberg, Germany). Statistical tests were appli
for descriptive and explorative reasons. T
Mann–Whitney test was used to compare t
variables between the groups (Lehmann 199
Associations between two variables were esta
lished based on Spearman’s rank-correlationco
ficient (Lehmann 1998). A P value of 0.05 w
considered to indicate an exploratory significa
difference. Arithmetic mean and standard err
were given for descriptive purposes.
Technical complications
Any problems with respect to implants, ab
ments, prostheses, or treatment as such w
recorded as complications. Survival was definas implants or prostheses not requiring replac
ment and still in function after 8 years. T
Albrektsson (1986) criteria were applied to det
mine implant success.
Prostheses presenting complications, such
fractures of metal frameworks or smaller repai
such as repair of acrylic parts, were consider
survivors but not successful.
Patients satisfaction
At the 8-year-follow-up, patients were asked
fill in questionnaires related to satisfaction a
the psychological effects concerning their iplant-supported bridges. Evaluation of functio
involving both chewing and phonetics, a
thetics, and overall satisfaction were recorde
Response alternatives for patients were as f
lows: 1 ¼ very satisfied, 2 ¼ satisfied, 3 ¼ neutr
4 ¼ dissatisfied, and 5 ¼ very dissatisfied. In a
dition, patients were asked whether they wou
have chosen the same treatment again, knowi
what this particular treatment consisted of.
Results
Patients
A total of 106 Astra Tech dental implants we
placed in the edentulous maxillae of 17 patien
(12 female, 5 male). On the day of surge
patients’ ages ranged from 41 to 69 years, wi
a mean of 55.6 7.3 years.
Eight patients were smokers (47%), four we
previous smokers (23.5%), and five were no
smokers (29.4%).
All patients had an opposing denture in t
mandible at the time of implant surgery to ensu
stable occlusion. Three patients had natu
teeth, nine had removable partial prosthes
Fig. 3. Bridge-like design with slight contact to the oral
mucosa, permitting the use of interdental brushes and
flossing techniques.
Fig. 4. Clinical situation after 60 months of function.
Screw-retained prostheses were removed for the first time
for microbiologic probing of the periimplant sulcus. Only
minimum mucosal irritations are visible.
Mertens & Steveling Implant-supported fixed prostheses in the edentulous maxilla
466 | Clin. Oral Impl. Res. 22, 2011 / 464–472 c 2010 John Wiley & Sons A
8/17/2019 Mertens, 8 Años Hibrida (1)
4/10
two had fixed partial prostheses, and one patient
had an implant-supported denture. Only two
patients had a complete denture.
Implants
In aggregate, 99 implants could be evaluated and
assessed throughout an observation period of 8
years (mean observation period, 8.34 0.53
years). Originally, 106 implants had been placed
in 17 patients eligible for clinical evaluation.
During the first year after installation, one pa-
tient died from cancer (six implants) and one
patient lost one implant during the healing per-
iod, which was not replaced. No further implant
losses occurred during the course of the study.
Patients received six to eight implants at surgery.
In most patients ( n ¼ 15), six implants were
placed to retain the fixed full-arch bridge
(88.2%). The 8-year cumulative implant survival
rate was 99%. When applying the Albrektsson
implant success criteria, an implant is defined as
being successful if the marginal bone loss is
1 mm or less within the first year after insertion
of the prosthesis and not greater than 0.2 mm in
each subsequent year of function. Using these
radiographic criteria on our patients, crestal bone
loss after 8 years of function should not exceed
2.4 mm in total. Throughout this study, only
four individual implants failed to meet these
criteria. Additionally, all implants were tested
individually for mobility and were found to be
clinically stable, no peri-implant radiolucency
was identified around any of the implants, and
no signs or symptoms of pain were reported.
Thus, the overall success rate according to Al-
brektsson et al. (1986) was 96% after 8 years.
Clinical examination
According to Mombelli’s plaque index, 92% of
the implants had a satisfactory oral hygiene
status (grades 0 and 1; Table 1) at the 8-year
follow-up. Bleeding on probing was also evalu-
ated, showing an incidence of bleeding in the
peri-implant mucosa of around 45% of the im-
plants. A high tendency towards bleeding wasfound in only one implant site.
Microbiologic probing of the periimplant su
cus showed normal flora in all cases, except f
two, after 60 months of function (Table 2).
Radiographic examination
Radiographic examination of the remaining
implants after 8 years of loading revealed a memarginal bone resorption of 0.3 0.72m
(minimum: 0 mm, maximum: 4.48mm). M
sially, a bone loss of 0.28 0.87mm was
corded; the distal value was 0.33 0.68m
Altogether, 62 implants (63% of all examin
implants) remained without any evidence
crestal bone-level changes or angular defects
the proximal sites. An additional 24 implan
(87% of all implants) showed a marginal bo
loss of less than 0.5 mm. Fig. 5 summarizes t
results of the radiographic assessment. Only fo
implants (4%) showed a bone loss greater th
2.4 mm. All four of these implants showed fomesial measurements worse than 2.4 mm, b
Table1. Scores of the clinical examination after 8years
Periimplant parameters 8 years
MPI MBI Mobility
Score 0 49 54 99
Score 1 42 38 0
Score 2 6 6 0
Score 3 2 1 0
Score range 0–3 in accordance with Mombelli et al.(1987).
MPI, Modified Plaque Index; MBI, Modified Bleeding
Index.
Table2. Results of microbiologic probing per patient analyzed after 60 months of function
Results of microbiologic probing
1 2 3 4 5 6 7 8 9 10 11 1 2 13 14 15 16
Actinobacillus actinomycetemcomitans
Actinomyces viscosus ( þ )
Tannerella forsythensis ( þ ) þ þ ( þ ) ( þ ) þ þ
Campylobacter rectus þ þ þ ( þ )
Treponema denticola ( þ ) þ ( þ )
Eikenella corrodens
(þ
)
(þ
) þ
Prevotella intermedia þ ( þ ) ( þ ) þ þ
Peptostreptococcus micros þ ( þ )
Porphyromonas gingivalis þ þ ( þ ) þ þ ( þ ) þ
Fusobacterium nucleatum þ ( þ ) þ þ þ þ
Actinomyces odontolyticus ( þ ) ( þ ) ( þ ) þ þ ( þ ) ( þ ) ( þ ) þ þ ( þ ) ( þ ) þ þ ( þ )
Campylobacter concisus
Campylobacter gracilis þ þ þ
Capnocytophaga gingivalis ( þ ) ( þ ) þ þ
Prevotella nigrescens ( þ )
Eubacterium nodatum
Streptococcus constellatus
Streptococcus gordonii þ þ
Streptococcus mitis ( þ ) þ þ ( þ ) þ þ ( þ ) ( þ ) þ þ ( þ )
Veillonella parvula þ þ þ þ þ þ þ þ þ ( þ ) þ þ þ ( þ ) ( þ ) þ þ þ
, negative; ( þ ), weakly positive; þ , positive; þ þ , strong positive; þ þ þ , very strong positive.
0%
20%
40%
60%
80%
100%
0
n=62
2
n=4
Marginal bone loss [mm]
mean: 0.3 mmSD: 0.72 mmmin: 0 mmmedian: 0 mmmax: 4.48 mmsample size: 99
Fig. 5. Frequency distribution including descriptive statistics of marginal bone loss after 8 years in function.
Mertens & Steveling Implant-supported fixed prostheses in the edentulous max
c 2010 John Wiley & Sons A/S 467 | Clin. Oral Impl. Res. 22, 2011 / 464–4
8/17/2019 Mertens, 8 Años Hibrida (1)
5/10
only three of these (3%) also had distal bone loss
measurements above 2.4 mm.
The analysis of marginal bone-level changes in
relation to implant length and diameter indicates
that shorter implants (9 and 11 mm) showed no
greater bone resorption than longer implants (13
and 15 mm). The Spearman rank correlation
coefficient showed an association between im-
plant length and bone loss ( r ¼ 0.22, P ¼ 0.03),
with higher losses with increasing implant length
(Fig. 7).
Large-diameter implants showed somewhat
less bone loss than small-diameter implants,
but without statistical significance (P ¼ 0.146).
Implants with a 3.5mm diameter showed a
marginal bone loss of 0.33mm; implants of
4 mm diameter showed a marginal bone loss of
0.2mm (Fig. 6).
The mean marginal bone loss around implants
related to smoking is presented in Table 3; no
exploratory differences were found between smo-
kers and nonsmokers.
Technical complications
The survival rate of the suprastructure was
100%. After 8 years, all patients were still wear-
ing the same fixed bridges. The most common
complications observed were related to the resin
part of the prostheses, that is, chipping of acrylic
teeth (three patients), ageing of the acrylic base,
or discolorations at the contact area between the
teeth and the acrylic base (six patients). All of
these complications were reparable without hav-
ing to replace the prosthesis or entailing high
costs, as compared with ceramic works. No
complications were recorded concerning fractures
of the metal frameworks or loosening or fracture
of abutments or abutment screws. During the
observation period, loss of the composite seals
over screw holes was recorded as well. The
prosthetic success rate was 82.4%.
Patients satisfaction
The results of the 8-year evaluation of function,
aesthetics, speaking, and overall patient satisfac-
tion ranged from highto very high (Table 4). After
8 years, all patients declared that they wouldchoose the same treatment concept again.
Discussion
Because of anatomical structure and specific bone
quality, implant treatment of the completely
edentulous maxilla is often associated with
higher implant failure rates and higher marginal
bone loss as compared with mandibular implants.
In this study, patients received fixed, screw-
retained, full-arch bridges with distal cantilevers
on six to eight implants, and they were examinedannually over a period of 8 years. A high homo-
geneity of the data was achieved by treating all
patients for the same indication. The prospective
study design, combined with the fact that almost
all patients were available for the complete ob-
servation period, is another strength of this study.
Additionally, not only implant survival but also
marginal bone loss, clinical parameters, micro-
biologic probing, and patient satisfaction were
observed and assessed.
With respect to implant survival, the results
this study are comparable with the outcome
similar studies analysing patients with fix
screw-retained implant dentures in the eden
lous maxilla ranging from 95.5% to 97.9% (F
rigno et al. 2002; Bergkvist et al. 200
Rasmusson et al. 2005; Fischer et al. 2008).
Further, literature search reveals that the su
vival rates of implants with rough surfaces a
significantly higher than those of machined im
plants. Moreover, the survival rates of machin
implants were found to decrease continuou
over the years, whereas the rates for roug
surface implants remained stable for up
10 years of follow-up (Lambert et al. 200
Lambert concludes that a rough surface on den
implants is important for stable, long-term
sults of fixed-implant rehabilitation of the ede
tulous maxilla.
The aspect of marginal bone stability is a
positively influenced by rough surface implan
as compared with machined implants (Web
et al. 2000; Watzak et al. 2006), consequen
leading to an increase in the overall impla
success (Van de Velde et al. 2007; De Bru
et al. 2008). Le Guéhennec et al. (2007) co
cluded in a review on surface roughness that
means of increased surface roughness not on
osseointegration can be enhanced, but also t
prevention of bone resorption.
Measurement of marginal bone-level loss ov
time is a valuable indicator in evaluating t
clinical performance of implants, because t
gradual loss of marginal bone eventually lea
to implant failure. By measuring each impla
mesially and distally, very accurate objecti
results can be obtained. All implants in t
present study were evaluated radiographica
on a regular basis. Initial intraoral radiograp
were taken after implant placement, followed
radiographs taken 6 months later at the tim
of prosthetic loading. After a further 6-mon
period, the first radiographic follow-up w
obtained, followed by annual radiographic co
trols. The accuracy of marginal bone-level me
surements is influenced by the precision of bo
the radiographic technique and the measureme
technique. To ensure reproducibility betwe
examinations, radiographs were taken using t
parallel technique, using commercially availab
film holders. Care was exercised to ensure th
threads on mesial distal sides of the implan
were clearly imaged (Bergkvist et al. 2004, 200
Fischer et al. 2008). To correct dimension
distortion, the apparent dimension of each i
plant was measured on the radiograph and com
pared with the actual implant size. Radiograp
were not standardized using individually fab
cated film holders for each implant at th
time, although the standardization of radiograp
0
0.5
1
1.5
2
2.5
3
3.5
4
3.5 4
implant diameter [mm]
m a r g i n a l b o n e
l o s s [ m m ]
Spearman's rank
correlation of implant
length and marginalbone loss: r = –0.15
(p=0.146)
Fig. 6. Marginal bone loss in relation to implant diameter.
0
1
2
3
4
5
9 11 13 15
implant length [mm]
m a r g i n a l b o n e l o s s [ m m ] Spearman's rank
correlation of implant
length and marginal bone
loss: r = 0.22 (p=0.030)
Fig. 7. Marginal bone loss in relation to implant length.
Mertens & Steveling Implant-supported fixed prostheses in the edentulous maxilla
468 | Clin. Oral Impl. Res. 22, 2011 / 464–472 c 2010 John Wiley & Sons A
8/17/2019 Mertens, 8 Años Hibrida (1)
6/10
would have further increased the comparability
and accuracy of the data. The measurement
technique used in this study, however, is iden-
tical to that used in most investigations analyzing
marginal bone levels in the edentulous maxilla
(Bergkvist et al. 2004; De Bruyn et al. 2008;
Fischer et al. 2008).
With respect to marginal bone stability around
the implants (mean marginal bone loss: only
0.3 mm after 8 years), the treatment outcome
can be rated as high. Our results in terms of
maintained marginal bone corroborate the long-
term results of other authors using the same
implant system – although for different indica-
tions (Rasmusson et al. 2005; Gotfredsen 2009;
Vroom et al. 2009).
From a statistical point of view, implant data
have to be considered as dependent data observa-
tions when assessing marginal bone-level
changes related to individual implants retaining
a full-arch restoration. Chuang et al. (2001)
statistically validated three different models for
estimating implant survival. The models they
used for studying a total of 660 patients were
based on (1) a random selection of one implant
per patient only; (2) the inclusion of all implants,
assuming independence among all implants of
the same subject; and (3) the inclusion of all
implants, assuming dependence among all im-
plants of the same subject. They were not able to
demonstrate significant differences and con-
cluded that both the survival point estimates as
well as the standard-error estimates varied very
little among the three models. Considering the
number of patients in this study, the indepen-
dence model was selected as appropriate to ana-
lyse the data available on implant level.
The analysis of marginal bone-level data with
respect to implant length in this study demon-
strated that shorter implants involve no higher
bone loss than longer implants.
These findings are supported by the recent
literature on short implants. While studies using
short machined implants document far lower
survival rates than longer implants (Winkler
et al. 2000; Herrmann et al. 2005), studies with
rough surface implants reported that implant
length did not influence the survival rates (Buser
et al. 1997; Testori et al. 2001; Feldman et al.
2004). Implant surface topography seems to be
one of the main factors influencing implant
survival. An unfavourable implant-to-crown ra-
tio was believed to cause overloading. The in-
creased bone stress leads to atrophy and higher
marginal bone loss (Rangert et al. 1997). A
systematic review by Blanes (2009), however,
demonstrated that implant-to-crown ratios do
not influence marginal bone loss. One article
showed even less marginal bone loss with higher
crown-to-implant ratios (Blanes et al. 2007).
Marginal bone loss was further assessed using
the Albrektsson success criteria (Albrektsson
et al. 1986). With an implant survival of 99%
and a respective implant success of 96% after 8
years, the difference between implant survival
and success was only minor. Albrektsson et al.
(1981) had already described the following factors
as preconditions for successful osseointegration:
implant material, implant design, surface quality,
status of the bone, surgical technique, and im-
plant loading conditions.
The exceptional use of native bone in this
study could have also contributed to the high
success rates, because patients requiring augmen-
tation procedures were excluded. Lambert et al.
(2009) showed that the survival rates of ma-
chined implants were significantly higher when
placed in native bone compared with implants in
augmented bone. However, this study also fou
that the survival rates for rough-surface implan
were the same whether placed in native
regenerated bone. Survival of machined implan
placed in augmented maxillary bone, in contra
decreased significantly over the years.
Concerning the number of implants necessa
to retain a fixed, full-arch restoration in t
edentulous maxilla, this study shows that t
use of six implants seems to be sufficient
providing long-term stability, because all, exce
for two, patients received six implants. Oth
studies report that for fixed maxillary reconstru
tions, eight implants distributed strategically a
necessary for long-term success (Lambert et
2009). However, our 8-year data demonstr
that six implants seem to be able to provi
long-term, stablereconstruction. Even with oth
loading modalities, such as early or immedia
loading, the survival rates of rough-surfaced i
plants are comparable to conventional loadi
protocols. Fischer et al. (2008) showed that the
were no significant differences between early a
delayed loading in the edentulous maxilla usi
five or six implants for implant-supported, fix
prostheses. Bergkvist et al. (2009) reported sim
lar survival rates, comparing conventiona
loaded and immediately loaded implants. A
fixed, screw-retained reconstructions were
tained by six implants.
The use of fixed implant rehabilitations of t
edentulous maxilla also seems to improve im
plant survival and reduce marginal bone loss
contrast to removable solutions (Hutton et
1995; Schwartz-Arad et al. 2005). Comparis
of various fixed prosthetic concepts such as eig
strategically distributed implants with retaini
segmented rehabilitations, that is, four thre
unit fixed bridges (Gallucci et al. 2004, 200
with one-piece, full-arch reconstructio
yielded no statistical differences (Lambert et
2009).
The advantages of screw-retained, full-ar
prostheses are – besides high hard- and soft-tiss
stability – the capability to compensate for com
plications such as divergent implant axes, lo
teeth, wide interdental spaces, missing cong
ence of implant location, and tooth position,
well as compensating for sagittal miscorrelatio
between jaws. Such adverse morphologi
Table3. Marginal bone loss around implants related to smoking
Exposure of implants
to smoking
Mean SE Minimum Median Maximum Sample size P -value
Mean bone loss (mm) – 0.15 0.04 0 0 1.62 57 0.07
þ þ 0.51 0.16 0 0 4.48 42
Marginal bone loss (mesial) (mm) – 0.08 0.03 0 0 1.46 57 0.12
þ þ 0.54 0.20 0 0 5.76 42
Marginal bone loss (distal) (mm) – 0.21 0.06 0 0 2.63 57 0.26
þ þ 0.48 0.13 0 0 3.21 42
Table4. Scores of the item denture satisfaction questionnaire 8 years after treatment
Satisfaction 8 years
Patients (N ) Function (eating) Speaking Appearance Satisfaction
Score 1 14 13 12 13
Score 2 2 3 4 3
Score 3 0 0 0 0
Score 4 0 0 0 0
Score 5 0 0 0 0
Scale range 1–5: 1 ¼ very satisfied, 2 ¼ satisfied, 3 ¼ neutral, 4 ¼ dissatisfied, 5 ¼ very dissatisfied.
Mertens & Steveling Implant-supported fixed prostheses in the edentulous max
c 2010 John Wiley & Sons A/S 469 | Clin. Oral Impl. Res. 22, 2011 / 464–4
8/17/2019 Mertens, 8 Años Hibrida (1)
7/10
8/17/2019 Mertens, 8 Años Hibrida (1)
8/10
implants placedin theposterior region. II: influenceof
the crown-to-implant ratio and different prosthetic
treatment modalities on crestal bone loss. Clinical
Oral Implants Research 18: 707–714.
Buser, D., Mericske-Stern, R., Bernard, J.P., Behneke,
A., Behneke, N., Hirt, H.P., Belser, U. & Lang, N.P.
(1997) Long-term evaluation of nonsubmerged ITI
implants. Part 1: 8-year life table analysis of a pro-
spective multicenter study with 2359 implants. Clin-
ical Oral Implants Research 8: 161–172.Carlson, B. & Carlsson, G.E. (1994) Prosthodontic
complications in osseointegrated dental implant treat-
ment. The International Journal of Oral & Maxillo-
facial Implants 9: 90–4.
Chuang, S.K., Tian, L., Wei, L.J. & Dodson, T.B. (2001)
Kaplan-Meier analysis of dental implant survival: a
strategy for estimating survival with clustered obser-
vations. Journal of Dental Research 80: 2016–20.
Danser, M.M., Van Winkelhoff, A.J., de Graaf, J., Loos,
B.G. & Van der Velden, U. (1994) Short-term effect of
full-mouth extraction on periodontal pathogens colo-
nizing the oral mucous membranes. Journal of Clin-
ical Periodontology 21: 484–489.
Danser, M.M., van Winkelhoff, A.J. & van der Velden,
U. (1997) Periodontal bacteria colonizing oralmucous membranes in edentulous patients wearing
dental implants. Journal of Periodontology 68: 209–
216.
De Bruyn, H., Collaert, B., Lindén, U. & Bjorn, A.L.
(1997) Patient’s opinion and treatment outcome of
fixed rehabilitation on Branemark implants. A 3-year
follow-up study in private dental practices. Clinical
Oral Implants Research 8: 265–271.
De Bruyn, H., Van de Velde, T. & Collaert, B. (2008)
Immediate functional loading of TiOblast dental im-
plants in fullarch edentulous mandibles: a 3-year
prospective study. Clinical Oral Implants Research
19: 717–723.
Dierens, M., Collaert, B., Deschepper, E., Browaeys, H.,
Klinge, B. & De Bruyn, H. (2009) Patient-centeredoutcome of immediately loaded implants in the re-
habilitation of fully edentulous jaws. Clinical Oral
Implants Reserach 20;: 1070–1077.
Esposito, M., Hirsch, J.M., Lekholm, U. & Thomsen,
P. (1998) Biological factors contributing to failures of
osseointegrated oral implants. (I). Success criteria and
epidemiology. European Journal of Oral Sciences
106: 527–551.
Feine, J.S. & Lund, J.P. (2006) Measuring chewing
ability in randomized controlled trials with edentu-
lous populations wearing implant prostheses. Journal
of Oral Rehabilitation 33: 301–308.
Feldman, S., Boitel, N., Weng, D., Kohles, S.S. & Stach,
R.M. (2004) Five-year survival distributions of short-
length (10 mm or less) machinedsurfaced and Osseo-tite implants. Clinical Implant Dentistry & Related
Research 6: 16–23.
Ferrigno, N., Lauretti, M., Fanali, S. & Grippaudo, G.
(2002) A long-term follow-up study of nonsubmerged
ITI-implants in the treatment of totally edentulous
jaws. Part I: ten-year life table analysis of a prospec-
tive multicenter study with 1286 implants. Clinical
Oral Implants Research 13: 260–273.
Fischer, K., Stenberg, T., Hedin, M. & Sennerby, L.
(2008) Five-year results from a randomized, con-
trolled trial on early and delayed loading of implants
supporting full-arch prosthesis in the edentulous
maxilla. Clinical Oral Implants Research 19: 433–
441.
Gallucci, G.O., Bernard, J.P. & Belser, U.C. (2005)
Treatment of completely edentulous patients with
fixed implantsupported restorations: three consecu-
tive cases of simultaneous immediate loading in both
maxilla and mandible. International Journal of Perio-
dontics and Restorative Dentistry 25: 27–37.
Gallucci, G.O., Bernard, J.P., Bertosa, M. & Belser,
U.C. (2004) Immediate loading with fixed screw-
retained provisional restorations in edentulous jaws:
the pickup technique. International Journal of Oraland Maxillofacial Implants 19: 524–533.
Gallucci, G.O., Morton, D. & Weber, H.P. (2009)
Loading protocols for dental implants in edentulous
patients. The International Journal of Oral & Max-
illofacial Implants 24 (Suppl.): 132–146.
Gotfredsen, K. (2009) A 10-year prospective study of
single tooth implants placed in the anterior maxilla.
Clinical Implant Dentistry and Related Research E-
pub August 6, doi: 10.1111/j.1708-8208.2009.00231.x.
Herrmann, I., Lekholm, U., Holm, S. & Kultje, C.
(2005) Evaluation of patient and implant characteris-
tics as potential prognostic factors for oral implant
failures. The International Journal of Oral & Max-
illofacial Implants 20: 220–230.
Heydecke, G., McFarland, D.H., Feine, J.S. & Lund,J.P. (2004) Speechwith Maxillary Implant Prostheses:
ratings of articulation. Journal of Dental Research 83:
236–240.
Hutton, J.E., Heath, M.R., Chai, J.Y., Harnett, J., Jemt,
T., Johns, R.B., McKenna, S., McNamara, D.C., Van
Steenberghe, D., Taylor, R., Watson, R.M. & Her-
mann, I. (1995) Factors related to success and failure
rates at 3-years follow-up in a multicenter study of
overdentures supported by Brånemark implants. The
International Journal of Oral & Maxillofacial Im-
plants 10: 33–42.
Jemt, T. (1991) Failures and complications in 391
consecutively inserted fixed prostheses supported by
Brånemark implants in edentulous jaws: a study of
treatment from the time of prostheses placement tothe first annual checkup. The International Journal of
Oral & Maxillofacial Implants 6: 270–276.
Jemt, T. (1994) Fixed implant-supported prostheses in
the edentulous maxilla. A five-year follow-up report.
Clinical Oral Implants Research 5: 142–147.
Johansson, G. & Palmqvist, S. (1990) Complications,
supplementary treatment, and maintenance in eden-
tulous arches with implant-supported fixed pros-
theses. I nternational Journal of Prosthodontics 3:
89–92.
Lambert, F.E., Weber, H.P., Susarla, S.M., Belser, U.C.
& Gallucci, G.O. (2009) Descriptive analysis of
implant and prosthodontic survival rates with
fixed implant–supported rehabilitations in the eden-
tulous maxilla. Journal of Periodontology 80: 1220–1230.
Le Guéhennec, L., Soueidan, A., Layrolle, P. &
Amouriq, Y. (2007) Surface treatments of titanium
dental implants for rapid osseointegration. Dental
Materials 23: 844–854.
Lehmann, E.L (1998) Nonparametrics – Statistical
Methods Based on Ranks. New Jersey: Prentice Hall.
Lekholm, U. & Zarb, G. (1985) Patient selection and
preparation. In: Branemark, P.–I., Zarb, G. & Al-
brektsson, T., eds. Tissue Integrated Prosthesis: Os-
teointegration in Clinical Dentistry , 199–209.
Chicago: Quintessence Publications.
Lundqvist, S., Lohmander-Agerskov, A. & Haraldson,
T. (1992a) Speech before and after treatment
with bridges on osteointegrated implants in the ed
tulous upper jaw. Clinical Oral Implants Research
57–62.
Lundqvist, S., Haraldson, T. & Lindblad, P. (199
Speech in connection with maxillary fixed prost
eses on osseointegrated implants: a three-y
follow-up study. Clinical Oral Implant Research
176–180.
Mombelli, A. & Mericske-Stern, R. (1990) Microbio
gical features of stable osseointegrated implants uas abutments for overdentures. Clinical Oral I
plants Research 1: 1–7.
Mombelli, A., Marxer, M., Gaberthuel, T., Grunder,
& Lang, N.P. (1995) The microbiota of osseoin
grated implants in patients with a history of per
dontal disease. Journal of Clinical Periodontology
124–130.
Mombelli, A., Van Oosten, M.A.C., Schürch, E.
Lang, N. (1987) The microbiota associated w
successful or failing osseointegrated titanium i
plants. Journal of Oral Microbiology and Immun
ogy 2: 145–151.
Quirynen, M., Alsaadi, G., Pauwels, M., Haffajee,
van Steenberghe, D. & Naert, I. (2005) Microbiolo
cal and clinical outcomes and patient satisfaction two treatment options in the edentulous lower j
after 10 years of function. Clinical Oral Impla
Research 16: 277–287.
Quirynen, M., De Soete, M. & van Steenberghe,
(2002) Infectious risks for oral implants: a review
the literature. Clinical Oral Implants Research
1–19.
Rangert, B.R., Sullivan, R.M. & Jemt, T.M. (19
Load factor control for implants in the poster
partially edentulous segment. The Internation
Journal of Oral & Maxillofacial Implants 12: 36
370.
Rasmusson, L., Roos, J. & Bystedt, H. (2005) A 10-y
follow-up study of titanium dioxide-blasted implan
Clinical Implant Dentistry & Related Research36–42.
Schwartz-Arad, D., Kidron, N. & Dolev, E. (2005
long-term study of implants supporting overdentu
as a model for implant success. Journal of Per
dontology 76: 1431–1435.
Testori, T., Wiseman, L., Woolfe, S. & Porter, S
(2001) A prospective multicenter clinical study
the Osseotite implant: four-year interim report. T
International Journal of Oral & Maxillofacial I
plants 16: 193–200.
Torbjörner, A. & Fransson, B. (2004) Biomechani
aspects of prosthetic treatment of structurally co
promised teeth. International Journal of Prosthodo
tics 17: 135–141.
Trulson, M. (2006) The tooth as a sensor in masticatory system. The Journal of the SDA
30–38.
Van de Velde, T., Collaert, B. & De Bruyn, H. (20
Immediate loading in the completely edentulo
mandible: technical procedure and clinical results
to 3 years of functional loading. Clinical Oral I
plants Research 18: 295–303.
Vroom, M.G., Sipos, P., de Lange, G.L., Grundeman
L.J., Timmerman, M.F., Loos, B.G. & van
Velden, U. (2009) Effect of surface topography
screw-shaped titanium implants in humans on cl
ical and radiographic parameters: a 12-year prosp
tive study. Clinical Oral Implants Research
1231–39.
Mertens & Steveling Implant-supported fixed prostheses in the edentulous max
c 2010 John Wiley & Sons A/S 471 | Clin. Oral Impl. Res. 22, 2011 / 464–4
http://-/?-http://-/?-
8/17/2019 Mertens, 8 Años Hibrida (1)
9/10
Watzak, G., Zechner, W., Busenlechner, D., Arnhart,
C., Gruber, R. & Watzek, G. (2006) Radiological and
clinical follow-up of machined- and anodized-surface
implants aftermeanfunctionalloading for 33 months.
Clinical Oral Implants Research 17: 651–657.
Weber, HP., Crohin, CC. & Fiorellini, JP. (2000) A 5-
year prospective clinical and radiographic study of
non-submerged dental implants. Clinical Oral Im-
plants Research 11: 144–153.
Winkler, S., Morris, H.F. & Ochi, S. (2000) Impla
survival to 36 months as related to length and d
meter. Annals of Periodontology 5: 22–31.
Mertens & Steveling Implant-supported fixed prostheses in the edentulous maxilla
472 | Clin. Oral Impl. Res. 22, 2011 / 464–472 c 2010 John Wiley & Sons A
8/17/2019 Mertens, 8 Años Hibrida (1)
10/10
Copyright of Clinical Oral Implants Research is the property of Wiley-Blackwell and its content may not be
copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written
permission. However, users may print, download, or email articles for individual use.
Top Related