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H
ealth care costs have grown in many Western
societies since the 1980s. Cost containment
remains a dominant theme within the health care
sector, and reliable information concerning the costs
of alternative treatment strategies is therefore rele-
vant. The various options for treating edentulousness
are compared in this report.
Dental implants were developed as an alternative
means of support for conventional dentures, and
their effectiveness has been well established during
the last decade. Growing evidence of this effective-
ness calls for research into the costs and outcomes of
this treatment. The main criterion for clinical success
seems to be survival,
1–7
although other objective cri-
teria, such as Gingival Index, Plaque Index, pocket
depth, and mobility of the implant, are also fre-
quently described.
1,8–11
In a number of other publica-
tions, the psychosocial effects of dental implants have
been considered.
12–16
Overall, these studies show
considerable improvement in the psychologic wellbe-
ing of patients treated with dental implants. Only one
article is known to have assessed costs.
17
The purpose of this study was to compare real
treatment costs during the first year of overdentures
supported by dental implants versus conventional
strategies.
The Cost of Dental Implants as Compared to
That of Conventional Strategies
Paul van der Wijk, MSc*/Jelte Bouma, PhD**/Marinus A. J. van Waas, DDS, PhD***/
Robert P. van Oort, DDS, PhD****/Frans F. H. Rutten, PhD*****
The effectiveness of dental implants is widely studied, especially in terms of their clinical outcomes. However,
from the policymaker’s point of view, variables other than safety and efficacy, such as the costs and effectiveness
of dental implants as compared to other treatment alternatives, are vital in decision making. This paper compares
the costs of different treatment strategies in a randomized clinical trial in patients with resorbed mandibles and
persistent problems with their conventional dentures: treatment with a mandibular overdenture on permucosal
dental implants, an overdenture on a transmandibular implant, new dentures after preprosthetic surgery, and new
dentures only. Data were gathered on an individual patient level to gain insight into specific cost episodes. Direct
costs were subdivided into labor, material, technique, and overhead. Data concerning these components were
gathered during the consecutive treatment phases in the first year. Results show that the resources used to treat a
patient with an overdenture supported by a transmandibular implant are seven times those of a complete new set
of dentures. Comparison of the cost ratio of an implant-retained overdenture supported by permucosal implants
and conventional new prostheses proves less unfavorable: 1:3. New dentures after preprosthetic surgery are
almost as expensive as treatment with permucosal implants.
(INT J ORAL MAXILLOFAC IMPLANTS 1998;13:546–553)
Key words: costs, dental implants, dentures
*****Economist, Northern Centre for Healthcare Research,
University of Groningen, Groningen, The Netherlands.
*****Sociologist, Northern Centre for Healthcare Research,
University of Groningen, Groningen, The Netherlands.
*****Professor of Prosthetic Dentistry, Academic Centre for
Dentistry Amsterdam, Free University of Amsterdam,
Amsterdam, The Netherlands.
*****Prosthodontist, Department of Oral and Maxillofacial
Surgery and Maxillofacial Prosthodontics, University
Hospital Groningen, Groningen, The Netherlands.
*****Professor in Health Economics, Institute for Medical
Technology Assessment, Erasmus University Rotterdam,
Rotterdam, The Netherlands.
Reprint requests: Dr P. van der Wijk, Northern Centre for
Healthcare Research, University of Groningen, A. Deusinglaan 1,
9713 AV Groningen, The Netherlands. E-mail:
P.van.der.Wijk@med.rug.nl
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Materials and Methods
Patient Selection. A randomized clinical trial was
conducted at the Department of Oral and Maxillofa-
cial Surgery and Maxillofacial Prosthodontics (Uni-
versity Hospital of Groningen) and the Department
of Oral and Maxillofacial Surgery (University Hospi-
tal of Nijmegen). Treatment with implant-retained
mandibular overdentures on two permucosal
implants was compared to treatment with a
mandibular overdenture on a transmandibular
implant and to two conventional treatments with a
new mandibular denture, one after preprosthetic
surgery and one without surgery. All patients
received a new maxillary denture.
Four possible treatment alternatives were in-
cluded. Surgery for permucosal implants (PI) was
performed under local anesthesia. Two different,
two-phase implant systems were used: the Bråne-
mark system (Nobel Biocare, Goteborg, Sweden), a
titanium screw-type cylinder, and the IMZ system
(Friedrichsfeld, Mannheim, Germany), a titanium
cylinder with titanium plasma-spray coating. During
the first phase, implant placement, two implants
were interforaminally placed in the mandible under
local anesthesia. The mean duration of the implant
operation was 73 minutes. After this operation, the
patient was seen two times for 15-minute check-ups.
Patients were not allowed to wear the conventional
mandibular denture during the first 2 weeks. After
initial wound healing, the denture was relined, and a
soft diet was prescribed. The abutment connection
took place after a healing period of 3 to 6 months. At
that time, the titanium abutments were connected to
the implants. The mean duration of this second oper-
ation was 41 minutes, and it was followed up by one
routine 15-minute check-up. For both implant sys-
tems, an implant- and tissue-supported overdenture
with a single-bar attachment was used (Figs 1 and 2).
Transmandibular implants (TMI) (Krijnen Med-
ical, Beesol, The Netherlands) were placed extra-
orally,
3
and surgery was performed under general
anesthesia. Mean operating duration, including the
impression for the superstructure, was 131 minutes.
The superstructure consisted of a triple-bar construc-
tion with cantilever extensions (Fig 3). The patient
was examined three times (60 minutes total) before
the superstructure was placed.
Preprosthetic surgery (PPS) took place under gen-
eral anesthesia. Thirty patients were treated surgi-
cally by interforaminal vestibuloplasty and deepening
of the floor of the mouth. The operation itself lasted
90 minutes, and 120 minutes more were needed for
diagnostics, follow-up, and relining of the prosthesis.
The group of patients which received new dentures
did not have any surgery. In all groups, dentures
were fabricated with an optimal fit and according to
the balanced occlusion principle.
In total, 240 patients were randomly assigned to
one of these four groups. For the economic evalua-
tion, two separate trials were combined in the
ADIOS (Academic Dutch Implant Overdenture
Study) group. In Nijmegen, three groups of 30
patients were treated either with mandibular over-
dentures, with overdentures supported by permu-
cosal implants, or with conventional new dentures.
All of these patients had a maximum mandibular
bone height of 14 mm. In Groningen, selection was
made based on the mandibular bone height. For the
The International Journal of Oral & Maxillofacial Implants 547
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Fig 1 Two Brånemark implants with a bar attachment. Fig 2 Two IMZ implants with a bar attachment.
Fig 3 A transmandibular implant placed according to Bosker.
3
group of patients with mandibular bone height above
15 mm, three treatment options were available: over-
dentures supported by permucosal implants, new
dentures after preprosthetic surgery, or conventional
new dentures. For the patients with a low bone
height (8 to 14 mm), preprosthetic surgery to obtain
an increase of the denture-bearing area would be
insignificant.
18
Thus, for the group needing mandibu-
lar prostheses only, two treatment options were avail-
able: overdentures supported by permucosal implants
or conventional new dentures. The whole concept,
ordered by the National Health Insurance Council of
the Netherlands, resulted in an uneven distribution of
patients. Nevertheless, it had several advantages: sim-
ilar treatment procedures were used and evaluated
and a larger research population was established.
Patients included in this study all had severely
resorbed mandibles and persistent problems with
their conventional dentures. They were referred to a
university clinic by general practitioners. The criteria
for inclusion in this investigation were edentulous-
ness in both jaws for at least 12 months, mandibular
bone height of 8 to 25 mm, and no general con-
traindications for implants or surgical procedures. All
subjects were informed about different treatment
options, possible risks, and the method of treatment
assignment. Written informed consent was required
for participation in the trial. Treatment was assigned
by means of a balancing procedure designed for an
equal distribution of patients over the treatment
groups with regard to variables that could interfere
with the outcome of the study.
16,19
This pretreatment
comparability was ensured by balancing all groups for
age, gender, period of edentulousness in the man-
dible, age of the existing mandibular denture, and
mandibular bone height. Table 1 shows the structure
of the treatment groups and their most relevant char-
acteristics. Only the number of dentures in the
mandible differed among the various treatment
groups (two-way analysis of variance [ANOVA]).
Study Design. In association with this clinical
trial, a cost analysis of all different treatment modali-
ties was performed. It was possible for patients to
refuse the allocated treatment, and nine did. For
these patients, the “intention to treat” principle was
applied, which means that patients were evaluated in
the treatment group to which they were originally
assigned regardless of their actual treatment. How-
ever, for the cost analysis these patients’ refusal was
irrelevant, because people who were not treated did
not generate any costs. The same principle holds for
patients lost through attrition: as long as they did not
show up at the dental clinic, no treatment costs
accrued. If effects would have been taken into
account, exclusion of these patients would have been
a probable source of bias.
The integral cost analysis was based on data related
to actual costs, and not on data concerning fees. Fees
represent revenue for the provider and in most cases
do not reveal actual costs. Since the study was con-
cerned with actual costs, and not fees, patients were
followed through the treatment process during the
first posttreatment year. Detailed hospital data were
collected for each patient. Costs were subdivided
according to the categories of labor, equipment, tech-
nique, and overhead during the different treatment
phases: examination, implant operation, abutment
operation, prosthodontic treatment, follow-up exami-
nations, and complications through 1 year after treat-
ment. A procedure comparable to the Resource-
Based Relative Value Scale
20,21
was used to calculate
costs. Cost components were divided according to
physicians’ labor and practice expenses. A conversion
factor was not used since for all components actual
costs were assessed completely and not relative to
other medical procedures.
The cost of labor was based on a recording of
treatment time at the individual patient level. Actual
costs were then determined based on the gross salary
of the dental staff. Costs of labor can be divided into
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Table 1 Patient Characteristics at Baseline
Treatment group
Transmandibular Permucosal Preprosthetic New
implants implants surgery dentures
Patient characteristics (n = 30) (n = 89) (n = 28) (n = 89)
Age (y) 53 55 53 57
Gender (%)
Males 28 23 37 29
Females 72 77 63 71
Time edentulous in mandible (y) 21 22 20 23
No. of mandibular dentures 3.5 2.8 2.3 2.8
Mean age of mandibular denture (y) 6.4 7.2 8.2 6.9
surgical and prosthodontic costs. The estimate of
labor costs included the duration but not the inten-
sity of the treatment.
Practice expenses were subdivided according to
material, hospital, and overhead costs. Material
included the costs of the dental implants, the new
conventional dentures, the abutments, and so forth.
All of the different cost components were gathered on
an individual patient level as well. At the hospital
level, a variety of diagnostic tests (blood tests, radi-
ographs) were performed on patients undergoing
general anesthesia (ie, the TMI group and those
patients who received preprosthetic surgery [PPS]).
Information on whether the test was performed on
individual patients was not always recorded. The costs
of diagnostic tests were estimated from the treatment
protocol. Other hospital costs were generated because
patients who received a transmandibular implant or
preprosthetic surgery were required to stay in the
hospital for 3 days. Finally, there were the overhead
costs. Each treatment made use of the normal hospi-
tal facilities, and therefore incurred the following
costs: reusable equipment, capital costs of the build-
ing and the inventory, consumables, laundry services,
cleaning, maintenance, electricity, administration, and
so forth. An estimate of the cost of floor space was
made by calculating the size of the dental department
and multiplying it by the historic value of office and
clinical space. All other costs (laundry, cleaning, main-
tenance) were approximated based on hospital expen-
diture for the different components within the total
budget. All costs originally were measured in Dutch
guilders and then converted into U.S. dollars. The
exchange rate in 1994 was approximately $1:Dfl1.6.
Statistical Analyses. To make the results more
comprehensive, mean values are used in the tables.
Differences in patient characteristics were tested by
means of a two-way ANOVA with a significance level
of = .05. For all cost data, a 95% confidence inter-
val was calculated based on the standard error of the
mean of all groups. No differences in costs relating to
bone height were found.
Results
Costs of Surgical Procedures. Table 2 shows the
total time spent by each different professional within
treatment, and the resulting costs. Time invested by
the prosthodontist and assistant does not vary signifi-
cantly. In the implant groups, more time was needed
to fabricate the superstructure, and the operation
time was of course higher, especially for the trans-
mandibular implant; this difference leads to pro-
nounced additional costs.
Costs of Prosthodontic Procedure. All groups
had the prosthodontic treatment performed accord-
ing to a standard procedure. The permucosal implant
group began prosthodontic treatment about 3 weeks
after the second operation. The group of patients
with a transmandibular implant had the superstruc-
ture placed within 24 hours of surgery, and the new
dentures were made 2 months later. The PPS group
was transferred to the prosthodontist 1 month after
the vestibuloplasty. Patients who received new den-
tures began their treatment with the prosthodontists.
Mean treatment time for the fabrication of new den-
tures was calculated on an individual patient level.
Table 2 presents the results, including all check-ups
until 6 weeks after treatment.
Other Costs. All patient groups undergoing sur-
gery incurred costs of operating room usage. Table 3
shows the practice expenses for all treatment groups.
For the operational procedures, a standard pack-
age of diagnostic tests (including an electrocardio-
The International Journal of Oral & Maxillofacial Implants 549
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Table 2 Total Treatment Time by Each Professional and Costs for Each Treatment Group
Treatment group
Transmandibular Permucosal Preprosthetic Complete
implants implants surgery dentures
Time Cost ($) Time Cost ($) Time Cost ($) Time Cost ($)
Dental surgeon 4 h 06 250 3 h 34 217 3 h 30 213 — —
Nurses 6 h 22 174 6 h 07 136 3 h 00 82 — —
Anesthetist 2 h 41 163 — — 0 h 30 30 — —
Assistant anesthetist — — — — 1 h 30 64 — —
Administrative nurse 0 h 30 12 0 h 40 15 0 h 15 9 — —
Prosthodontic procedure
Prosthodontist 4 h 38 197 4 h 40 200 3 h 58 168 4 h 06 175
Assistant to prosthodontist 4 h 38 100 4 h 40 102 3 h 58 84 4 h 06 87
Total 896 670 650 272
95% confidence interval 875–917 648–692 616–684 248–296
gram) was used. Patients undergoing general anesthe-
sia (TMI and PPS) stayed in the hospital for 3 days at
a cost of $1,500. Medication consisted of antibiotics
and analgesics. Material costs were divided according
to equipment, implants, and prosthesis. Different
equipment and instruments were used for each treat-
ment modality during the surgical and prosthodontic
procedures. The instrument case for the transman-
dibular implant was used on average for the operation
of 30 patients. The total costs of an instrument case
with tray including an adjustable drill guide, super-
structure drill guide, several screwdrivers, drill
sleeves, tap sleeves, fasteners, and lock screws are
about $6,000, or $200 per patient. This does not
include drills and taps ($145 per patient). The use of
disposables for the permucosal implants differs some-
what for the Brånemark and the IMZ systems. The
Brånemark system uses special disposables for
implant patients, whereas IMZ uses the regular
instrumentation of a dental surgeon. However, the
resulting differences in costs per patient were not
dramatic (about $50 per patient), so the average cost
of both systems was used. Total costs of disposables
were $175 per patient (drills, screw taps, screws, and
the capital costs of a control unit).
Other material costs mainly represent those of
the implants themselves, the abutments, the super-
structure, and the dental prosthesis. Overhead costs
were attributed to the treatment groups on the basis
of total treatment time. Table 3 provides an overview
of the material and overhead costs per treatment
group.
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Table 3 Practice Expenses (in Dollars) Per Treatment Group
Treatment group
Transmandibular Permucosal Preprosthetic Complete
implants implants surgery dentures
Hospital costs
Laboratory tests 75 — 75 —
Radiographs 63 63 63 —
Electrocardiogram 18 — 18 —
Hospital room 1,500* — 1,500* —
Operating room
Minimum 469**
Maximum 1,594 434 469 —
Medication 12 12 12 —
Material costs
Equipment 345 175 — —
Implants 2,130 455 — —
Prosthesis 1,475 1,220 570 575
Overhead costs 400 412 392 211
Total 6,487–7,612 2,771 3,099 786
95% confidence interval [6,387–7,712] [2,669–2,873] [3,038–3,160] [752–820]
**Average length of stay was 3 days in a university hospital.
**Due to the insurance system in the Netherlands, part of the cost of the transmandibular implant (nobody
knows which) is accounted for in the bill of the operating room. The minimum cost pertains when the implant
is paid largely out of this fee; the maximum cost represents the fee for a very difficult operation and almost no
payment for the implant itself.
Table 4 Time and Costs of Follow-up for Each Treatment Group
Treatment group
Transmandibular Permucosal Preprosthetic Complete
implants implants surgery dentures
Time Cost ($) Time Cost ($) Time Cost ($) Time Cost ($)
Dental surgeon 0 h 50 55 0 h 40 33 0 h 10 11 — —
Dentist 0 h 67 52 0 h 48 37 0 h 20 16 0 h 40 30
Dentist assistant 0 h 67 30 0 h 48 22 0 h 20 9 0 h 40 17
Dental hygienist 0 h 35 19 0 h 50 29 — — — —
Total labor costs 156 121 36 47
Material 68 119 13 19
Overhead 118 77 10 28
Total costs of follow-up 342 317 59 94
Follow-up Costs (Through the First Year). In
some patients, complications greatly influenced the
total treatment cost. Follow-up costs were calculated
according to the number and average duration of
dentist visits. In addition, material and overhead
costs were accounted for as described above. In
Table 4, the labor time of follow-up treatment is
shown for each treatment group. Because of visits to
the dental surgeon and the dental hygienist, both
implant groups were significantly more expensive
than the conventional treatments with respect to fol-
low-up. In total, these costs amount to more than
$300 for the first year, while follow-up treatment for
patients with a new denture cost less than $100. Dur-
ing the first year, the average follow-up time for the
implant groups was 48 minutes (PI) and 67 minutes
(TMI) with the dentist and 50 minutes (PI) and 35
minutes (TMI) with the dental hygienist. This follow-
up treatment included aftercare and maintenance of
a healthy oral condition.
Total Costs (Through the First Year). The
costs of each treatment strategy can be divided into
the components of labor, material, and overhead
(Table 5). The costs for the first year of treatment
total between $7,600 and $8,800 for an overdenture
supported by a transmandibular implant. The total
cost is seven times that of treatment involving new
complete dentures. Treatments with an overdenture
supported by permucosal implants or new dentures
after vestibular surgery are similar in terms of their
cost, which is almost 3.2 times as much as new com-
plete dentures. The higher cost of the transmandibu-
lar implant and the preprosthetic surgery result from
the need for an operation under general anesthesia
(hospital stay, diagnostic tests, operating room costs).
Costs of aftercare were included for the first year. In
these costs, failures of new dentures were included.
Sensitivity Analysis. The purpose of a sensitivity
analysis is to test the validity of conclusions made
over a range of reasonable values for the assumptions
made in the baseline analysis. In this sensitivity analy-
sis, the threshold values at which the conclusions
about the total costs would change were calculated. A
summary of the sensitivity analysis and its relation to
the main analysis is shown in Table 6. The model is
based on the costs for the first year. One of the most
important assumptions for generalization is the sur-
vival rate. Assuming that 100% of the implants in
patients in the transmandibular and permucosal treat-
ment groups would survive, the treatment costs are
$7,394 and $3,363, respectively ($822 and $375
cheaper). The other cost components do not have a
significant differentiating impact on total costs
between groups, with the exception of material costs.
If the costs of the dental equipment necessary to use
dental implants would increase by 25%, total costs of
the implant groups would increase by $1,006 and
$482 for the transmandibular and permucosal groups,
respectively. The annual figures do not change dra-
matically if one or the other estimates is varied.
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Table 5 Total Cost of Treatment (in Dollars) During the First Year
Treatment group
Transmandibular Permucosal Preprosthetic Complete
implants implants surgery dentures
Labor
Surgery 599 368 398 —
Prosthodontics 297 302 252 262
Check-ups 156 121 36 47
Practice expenses
Materials
Implants 2,975 370 — —
Instruments 199 99 — —
Disposables 145 114 — —
Prosthesis 631 1,220 570 575
After treatment 68 119 13 19
Overhead
Treatment 400 412 392 211
After treatment 118 77 10 28
Hospital costs
Hospital stay 1,500 — 1,500 —
Operating room 469–1,594 434 469 —
Diagnostic tests 168 75 168 63
Total first-year costs 7,605–8,830 3,711 3,808 1,205
95% confidence interval 7,494–8,951 3,644–3,858 3,712–3,894 1,170–1,240
Index 631–733 308 316 100
Discussion
This paper has described in some detail the total
treatment costs of a specific new technology: dental
implants and overdenture treatment. Although few
articles on this particular subject have been pub-
lished in the dental literature, this information could
be crucial in light of the dwindling resources for
health care. With regard to labor, material, and hos-
pital expenses, the detailed information that was col-
lected enabled the calculation of per-patient costs.
The resources used to treat a patient with an over-
denture supported by a transmandibular implant
could provide nearly seven patients with new com-
plete dentures. If one compares a conventional new
prosthesis with an implant-retained overdenture sup-
ported by permucosal implants, the proportion of
costs becomes more favorable, namely 1:3. New den-
tures requiring preprosthetic surgery are almost as
expensive as treatment with an overdenture sup-
ported by permucosal implants. These figures com-
pare to those of Jönsson and Karlsson,
17
with one
exception. In their study, the permucosal implant
alternative was much more expensive, but this is only
logical since they evaluated implants with a fixed
prosthesis.
The results of the study seem rather robust. The
sensitivity analysis shows that threshold values for
various cost estimates, for which conclusions alter,
are unrealistic. Furthermore, the confidence inter-
vals are rather small, which suggests that collecting
individual data is an accurate method to estimate
costs. The relatively small standard deviations con-
firm the relative homogeneity of the study group. In
only a very few patients were enormous costs needed
to improve the oral health status. The presented data
seem useful for other purposes, because the out-
comes look comparable to those reported in the liter-
ature.
1,3,7,10
In the first year, a 92% survival of the
implants was measured. The aforementioned studies
all claimed survival rates between 89% and 96%.
The method used for cost analysis closely resem-
bles the Resource-Based Relative Value Scale
adopted by the U.S. Congress in 1989. Such a system
provides information that accurately reflects the
resource cost required to deliver a service. Although
this method was not used in the Netherlands for
determination of reimbursement levels, it provides a
better understanding of true costs than do tariffs.
The relative comparison of different types of maxillo-
facial procedures becomes well-founded. The cost
figures are useful not only for societal comparisons,
but for insight into financial flow in institutions and
for individual dentists. A discussion of inadequate
reimbursement levels could be the result.
Although the present data support general conclu-
sions, this study has several shortcomings. Patients
were treated in a clinical setting in an academic hos-
pital, and this can create certain biases. First, dentists
connected to a hospital may be more experienced
than general practitioners. Therefore, the survival
rates could be somewhat overstated. Second, over-
head costs in an academic hospital are probably much
larger than in a general practice. In addition, only
patients with a marginal bone height between 8 and
25 mm were selected. All patients had a long experi-
ence with complete dentures, and they still had com-
plaints. The population could be described as “dental
cripples.” Therefore, it is possible that the reported
costs are somewhat higher than the costs for implants
placed in routine practice settings. However, the ratio
between the costs of the different treatment options
can be generalized to other settings.
One of the most important shortcomings of such a
comparison is the lack of data related to long-term
costs. In the short term, dental implants are more
expensive. However, it is likely that parts of these
additional short-term costs will lead to savings in the
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Table 6 Summary of the Primary Analysis (Average Costs) and the Sensitivity
Analysis (Additional Costs Under Various Assumptions), in Dollars
Treatment group
Transmandibular Permucosal Preprosthetic Complete
implants implants surgery dentures
Primary analysis 8,216 3,748 3,776 1,179
Survival of implants: +10% 822 375 0 0
Aftercare: +25% 86 79 15 24
Operating time: +25% 150 92 97 0
Material costs: +25% 1,006 482 145 148
Overhead costs: +25% 156 129 104 78
Hospital costs: +25% 665 158 534 16
future because, for example, of the need for fewer
rebasings and relinings. This study has shown that
considerable additional investment is necessary for
dental implants, as compared to traditional treat-
ment. Costs of aftercare were considerably higher in
the implant groups, so initial differences in costs dur-
ing the treatment phase will most probably not be
compensated for in the long run. Of course, some of
the conventional prostheses, as well as overdentures
supported by implants, will fail. For both treatment
options, all complications during the first year were
included. In all circumstances, the patients finished
the first year in their own treatment group. There-
fore, it was not possible to estimate costs of failure in
the long term. However, between 25% and 33% of
the patients in the CD group opted for implants after
1 year.
22
Furthermore, in 17% of the patients, adjust-
ments to their prosthesis had to be made. The cost
ratio in this study could actually decrease in the long
run, thereby making implant-supported prostheses
less economically unfavorable relative to conven-
tional prostheses. The question remains whether the
reported benefits of dental implants
1–17
justify the
additional investment described here. This is the
cost-effectiveness issue, about which more will be
reported later.
Acknowledgments
This study was financially supported by the National Health Insur-
ance Council of the Netherlands.
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