A patient interview in which the clinician asks key questions and
listens carefully to the answers provided is the critical first step to successful treatment of the edentulous
patient. Only with appropriate treatment planning can patient-specific
restorations (ie, the most appropriate treatment for each patient) be delivered
PATIENT INTERVIEW AND EVALUATION
The essential information that must be elicited from the patient
evaluation for the two-implant overdenture:Does the patient want more retention of
an existing denture? Or does he or she hope to replace the denture with a fixed
restoration?It is important for
the clinician to differentiate between patient wants and preferences. A want may or may not be related to the
treatment, but a preference infers
that through sufficient education, the patient has a full understanding of what
the treatment and/or prosthesis does or does not include.
Sound treatment planning and decision-making is a balance among:
- Patient preference: an “informed
consent” of treatment choice;
- Financial considerations: what the
patient can afford; and
- Clinical factors: what is clinically
necessary and feasible based upon the patient’s medical and dental history and other
presenting circumstances determined upon extensive clinical examination, study
casts, and radiographic evaluation (ie, the quality, quantity, and shape of the
residual bone) (Figure 2).
As in all implant therapies,the final two-implant overdenture will
require some follow-up treatment and maintenance to ensure a predicable level
of patient comfort and satisfaction. A thorough and clear review of potential
maintenance requirements and their associated costs and time requirements
should be provided before treatment begins.
THE CONVENTIONAL DENTURE
Traditionally, the prosthetic rehabilitation of edentulous patients has
focused on the replacement of lost structures with removable prostheses.
Although the obvious disfigurement of edentulism may be markedly improved by
dentures,1 studies indicate that the function of clinically
acceptable dentures is often poor and leads to overall negative treatment
For those patients treated with complete
dentures, research also indicates that their most important priorities are
comfort, stability, and the ability to chew, yet it has been reported that over
50% of mandibular denture patients have problems with stability and retention
and their masticatory performance is markedly reduced (25% to 15% of that of
adults with natural dentition).4 Overall, mandibular dentures cause
many more problems than maxillary dentures, and their overall high level of
patient dissatisfaction dictates that dental professionals consider a new
paradigm for the management of such patients.
The biotechnical achievement of osseointegration has been a significant
breakthrough for edentulous people. Numerous studies have demonstrated that the
mandibular two-implant overdenture is a simple and effective solution for the
edentulous patient.5 Mandibular two-implant overdentures have shown
to be superior to conventional dentures in randomized and non-randomized
clinical trials ranging in duration from six months to ten years.6-10
This treatment has demonstrated a high level of implant success (97% to 100%),
long-term prosthesis survival, and a consistent high level of patient
satisfaction. It represents a much-needed treatment modality that is highly
predictable, yet less invasive, less expensive, and less complex as compared to
other implant options.
Restoration with a mandibular two-implant
overdenture will provide patients with significantly overall better treatment
outcomes than a conventional denture and should become the first choice
standard of care for the edentulous patient. The two-implant overdenture
specifically addresses the effects of edentulism in numerous ways.
1. Bone Loss
Progressive loss of tissue volume further debilitates these patients in
terms of their disfigurement and their ability to bite and chew. The pathologic
resorptive process may be significantly
reduced with this treatment. Studies indicate the anterior mandibular bone
beneath an implant overdenture may resorb as little as 0.1 mm annually (ie, 25%
as much as is observed with conventional dentures) or remain at 0.5 mm after a
five-year period.11 Additionally, increased function after treatment
appears to result in load-related bone formation that minimizes the physiologic
age-related mandibular bone mineral content loss.12
A randomized controlled clinical trial compared between-group pre- and
posttreatment nutritional status in patients with mandibular two-implant
overdentures and those with new conventional dentures.13 Evaluation
of blood parameters found significant
increases in concentrations of serum albumen, hemoglobin, B12, and carotene
in patients treated with two-implant overdentures while no significant change
was found in patients restored with conventional prosthesis. This and other
clinical data suggest that providing edentulous people with even the
least-complicated forms of implant prosthesis encourages and enables patients
to modify their diets and improve their nutrition, which may have considerable impact on their general
3. Quality of Life
Evidence utilizing questionnaires of sufficient sensitivity to provide
reliable data (ie, oral health implant profiles, VAS measurements) suggests
that quality of life ratings for oral
health are higher for patients who receive two-implant overdentures than
for those with new conventional dentures.14,15 This is of
considerable importance, indicating that this simple implant rehabilitation may
actually restore a patient’s quality of life that had been previously lost!
Therefore, the evidence currently available
suggests that the restoration of the edentulous mandible with a conventional
denture is no longer the most appropriate choice of treatment. There is
overwhelming evidence that the mandibular two-implant overdenture will provide
patients with a significantly overall better treatment outcome and should be
the first-choice standard of care for edentulous people.
INDICATIONS FOR THE TWO-IMPLANT
The two-implant overdenture is indicated for all fully edentulous
patients (Class I to Class IV) who are capable of undergoing a minor surgical
procedure and the placement of two dental implants. Specifically this includes:
- The maladaptive or unsatisfied
denture patient who demands greater retention and oral comfort;
- The middle-aged to elderly denture
patient who desires a more stable mandibular denture; and
- The partially edentulous patient
with severely compromised dentition (ie, about to become edentulous) that
cannot be successfully maintained to retain or support a prosthesis.
CONTRAINDICATIONS FOR THE TWO-IMPLANT OVERDENTURE
- Insufficient available bone for
implant placement (ie, less than 5 mm to 7 mm);
- Psychological denture intolerance
(ie, a conspicuous discrepancy between objective findings and subjective
patient complaints); and
- Medical conditions, which may
include uncontrolled metabolic diseases (eg, uncontrolled diabetes mellitus).
Previous history of radiation to the
intended area of implant placement and the use of immunosuppressives must be
carefully evaluated on an individual basis. This treatment should also be used
cautiously in patients sensitive to the bulk of a conventional denture and in
younger patients, for whom a greater number of implants would be more ideal for
anterior and posterior bone preservation. Neither increasing age nor
osteoporosis has been shown to contraindicate successful osseointegration of
(Continued from page 1 )
1) Implant-retained and supported (ie, rigid): These prosthesis require
multiple implants and will function most similarly to a fixed partial denture.
Although a patient can remove them for hygiene, when in place they will have no
2) Combined implant-retained and soft tissue-supported (ie, nonrigid):
These prostheses will require fewer implants and include both the mandibular
two-implant unsplinted and bar overdentures. Although they are associated with
a high level of patient satisfaction and are highly retentive, when in place
they will have (by design) some rotation and therefore some movement. It is
helpful to explain to patients how this prosthesis is expected to function.
GENERAL TREATMENT PLANNING
Implant overdentures are space
sensitive. While they are often the treatment of choice for the severely
atrophic jaw, they paradoxically require the most restorative space as compared
to other fixed prostheses. Generally, bar overdentures require more space than
do unsplinted overdentures. Therefore, an evaluation of available restorative
space or the attainment of the necessary space is critical to avoid overcontoured
lingual areas or a thinning of acrylic that will increase the incidence of denture
fracture. Careful prosthetic and surgical planning is essential for the
The treatment challenges will vary from the
minimally resorbed mandible (ie, Class I), which may paradoxically be difficult
in terms of a lack of available space within the profile of the denture. For
these patients additional space may be attained in one of two ways:
1. Prosthetically--Fabrication of a new two-implant overdenture with an
increased vertical dimension (if such freeway space exists); and/or
2. Surgically--By moderately reducing the residual ridge and then the conversion of existing denture.
For the severely resorbed mandible (ie,
Class IV), available space is not a concern. Less retention and stability is
expected, however, due to an overall diminished residual ridge and therefore a
smaller denture base.
The treatment is generally more
straightforward when a patient presents in the fully edentulous state, meaning
they have already experienced the wearing of a removable denture. It is more
difficult when the patient will experience the transition from fixed to a
removable prosthesis. The success of overdenture treatment is dependent on the
classical principles of denture fabrication and the placement of implants
should not be a substitute to these tenets. Ultimately, the form and contour of
a two-implant overdenture must be similar to a conventional denture, and an
adequate base extension and adaptation to the remaining structures are basic
Appropriate treatment planning culminates in selection of an appropriate
restorative design for the patient. It is
critical to select a final restorative design for the two-implant overdenture
before starting the case (ie, prior to implant surgery). Since the
philosophical goal of the mandibular two-implant overdenture is to make implant
therapy accessible and affordable for patients, a significant aspect of design
selection is deciding whether to restore the patient with a new two-implant
overdenture or to convert an existing denture to a two-implant overdenture (Figures 3 and 4). This decision may have a profound impact on
treatment time, costs, and case acceptance.
Can I convert
existing denture to a two-implant overdenture or do I need to fabricate a new
two-implant overdenture? This is a critical question initially, and arriving at
a decision involves a thorough understanding of many factors such as aesthetics
(ie, extraoral, facial, intraoral), vertical dimension, and the patient’s
subjective needs. An understanding of space requirements, however, will often
be the determining factor. If indicated, the conversion strategy should help
make this treatment accessible and affordable for most patients.
- Feine JS, Carlsson GE. Implant Overdentures: The Standard of Care
for Edentulous Patients. Carol Stream,
IL: Quintessence Publishing,
- Berg E. The influence of some anamnestic,
demographic, and clinical variables on patient acceptance of new complete
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Oral findings in elderly nursing home residents in selected countries: Quality
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J Oral Maxillofac Surg 1995;53(10):1176-1173.
- Raghoebar GM, Meijer HJ, Stegenga B, et al.
Effectiveness of three treatment modalities for the edentulous mandible. A five
year randomized clinical trial. Clin Oral Implants Res 2000;11(3):195-201.
- Geertman ME, Boerrigter EM, Van’t Hof MA, et al. Two-center clinical trial of implant-retained
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- Awad MA, Lund JP, Dufresne E, Feine J.
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- Jemt T, Chai J, Jarnett J, et al. A 5-year
prospective multicenter follow-up report on overdentures supported by
osseointegrated implants. Int J Oral Maxillofac Implants 1996;11(3):291-80.
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JA, Heydecke G, Pawliuk J, et al. The effects of mandibular two-implant
overdentures on nutrition in elderly edentulous individuals. J Dent Res
- Awad MA, Locker D, Korner-Bitensky N, Feine J.
Measuring the effect of intra-oral implant rehabilitation on heatlh-related
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- Awad MA, Lund JP, Shapiro SH, et al. Oral
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