Maintenance Considerations for the Mandibular Two-Implant Overdenture
Joseph R. Carpentieri, DDS • Dennis P. Tarnow, DDS
Both fixed and removable
prostheses require maintenance and this must be discussed with patients prior
to treatment. Maintenance of the two-implant overdenture is generally less
complicated, less expensive, and easier for both the patient and the dentist
than maintenance of a fixed implant prosthesis.
Patients should be instructed to
maintain peri-implant health by simple brushing around the abutments with a
standard toothbrush. Aftercare of the overdenture is similar to that of a
conventional denture with regard to brushing. Some of the commercial denture
cleaning products, however, may adversely affect the retentive elements.
Instructions should be given regarding the use of specific corrosive products
Recent consensus indicates that
the overall prosthodontic maintenance requirements of mandibular overdenture
treatment are greater during the first year of service than in subsequent
years.1 The following is an outline of the most common and
consistent complications and patient requirements as reported in the
Alteration of the denture base
contour as a result of pain and discomfort is reported to be the most common
initial problem following treatment. An increased awareness of the maxillary
denture may also be observed and/or the maxillary denture may be perceived as
unsatisfactory as compared to the now more stable lower prosthesis. Adjustments
to the maxillary denture may also be necessary due to an increase in the
loading of the overdenture.
of Retentive Devices
Clips, springs, and other
retentive elements may loosen within the acrylic base or require replacement.
These are the most common complications/repairs, and they are of clinical
significance. The key points are as follows:
studies indicated a high level of loose abutments with ball attachments for the
unsplinted design. Due to redesigned one-piece components and higher preload
values, however, the attachments no longer exhibit this characteristic.
patients are expected to present with decreased retention force over time,
leading to the following conclusions:
1) It is generally
desirable to begin with the most retentive components that still allow the
patient to remove the prosthesis. This maintains a higher level of retention
over time and allows further alteration of retention to address a patient’s
specific needs. This principle should be balanced with the goal of choosing
components that are easy to adjust (ie, reactivate) or replace without the need
for complicated laboratory support (ie, reline).
parallelism and proper position will have a significant impact on long-term
prosthetic maintenance needs (ie, nonparalleled implants) and will generally
require more maintenance than more paralleled implants.
3) A metal housing
supporting a plastic retentive matrix is mandatory in terms of simplicity to
alter/change retention as compared to a matrix directly attached to the
acrylic. In the latter case, a closed-mouth complete arch-impression technique
is utilized in which the position of the attachments and soft tissue are
registered. This involves laboratory support with additional costs.
4) The use of metal
(eg, titanium, gold) for ball attachments has been implicated in the wear of
the head of the matrix. With further prospective evaluation, this observation
may lead to favoring the use of plastic matrices.
The need for reline of the
overdenture may be indicated by the presence of one or more of the following
activation and replacement of the matrices;
of stability in an anteroposterior direction;
adjustments of the contour of the fitting surface; and
in the accumulation of food beneath the overdenture.
changing a retentive element, the need for relining must first be confirmed
with a material on the fitting surface of the denture. If this thickness is
greater than about 1 mm, then a reline may be necessary. The primary objective
of relining the overdenture is to limit extensive rotation and to maintain
well-distributed contacts between the intaglio surface of the denture and the
It is also important
to consider how long the patient has been edentulous in anticipating the need
for relines (ie, the newly edentulous patient should be evaluated carefully
within the first year when most bone loss occurs by comparison with a patient
who has been edentulous for many years, in whom bone loss has already
Because fracture may occur as a
result of insufficient bulk of overdenture acrylic, the question arises as to
whether it is necessary to use a cast metal base for the two-implant
overdenture. In view of the desire to minimize restorative cost to the patient
and of success rates with sufficient bulk of acrylic, it is consensus that a
metal base or stiffener should not be considered a standard procedure except in
the case of the minimally resorbed mandible, in which the acrylic base will be
excessively thin. In most cases, however, this may be avoided with careful
Excessively thin prosthetic teeth
may fracture. This may be avoided with careful planning and proper implant positions.
Successful application of the
surgical principles will have a profound impact on the ease of fabrication of
definitive prosthesis as well as long-term maintenance considerations.
Mucositis and hyperplasia have
been observed more commonly among patients restored with splinted bar
overdentures, while decubitus ulcers have been observed more often among those
restored with nonsplinted overdentures.
A regimen of at least annual
patient recalls is recommended to allow evaluation of retentive elements, hard
and soft tissue changes, and fit of denture base (eg, poor adaptation will
increase rotation and increase wear of components); soft tissue maintenance by
a hygienist; evaluation of occlusion; and radiographic follow-up. Although the
frequency of post-insertion prosthodontic maintenance is not possible to
predict, with careful case selection and meticulous planning, these needs may
be minimized. More frequent patient recalls may be indicated for those with
poor hygiene around the two implants. It is important to check for occlusal
changes, stability, and soft tissue health in the initial three to six months.
- Payne AG, Solomons YF. The
prosthodontic maintenance requirements of mandibular mucosa-and
implant-supported overdentures: A review of the literature. Int J Prosthodont