The implant-retained maxillary overdenture in the edentulous maxilla

A number of edentulous patients experiences problems with a conventional
complete upper denture. Lack of retention and stability, together with an
unpleasant feeling due to the palatal plate are the main complaints of these
patients. An overdenture on endosseous implants gives the opportunity to
improve retention and stability of the prosthesis and also have a reduction of
the palatal plate.
There are a number of prospective studies on overdentures retained by implants
in the maxilla (references). A study, in which different treatment options are
compared to each other, has not been published yet. Besides patient*s
satisfaction, clinical performance of the implants also is an important factor
in the determination of success. Patient satisfaction has rarely been part of a
prospective study on implant-retained maxillary overdentures.

The aim of the study is to compare the treatment with four or six implants in
combination with an overdenture for patients with lack of retention and
stability of their complete upper denture.
The clinical function of the implants and overdenture, radiographic
peri-implant boneheight changes and patient satisfaction are part of this
prospective randomized trial.

Group 1: There is sufficient bone height in the frontal region of the
edentulous maxilla (>10 mm) and above the maxillary sinus (>5 mm), bone width
is sufficient (>5 mm). If needed a sinus elevation procedure with intra-oral
bone will be performed in the same session as the implantation procedure. The
patient has an edentulous mandible and four implants are inserted in the
interforaminal region.

Group 1a: Four implants of at least 10 mm length are inserted in the frontal
area of the maxilla. (test group)

Group 1b: Six implants of at least 10 mm length are inserted in the frontal
area of the maxilla. (control group)



Groep 2: There is insufficient bone height in the frontal region of the
edentulous mandible (<10 mm) and above the maxillary sinus (< 5 mm), bone width
of the maxilla is less than 5 mm. A sinuselevation procedure with bone from the
iliac crest is performed in a separate session. After a period of three months
of wound healing the implant procedure is performed. The patient has an
edentulous mandible and four implants are inserted in the interforaminal region.

Group 2a: four implants (two at the left side and two at the right side) are
inserted in the lateral region of the maxilla. (test group)

Group 2b: six implants (two at the left side and two at the right side) are
inserted in the lateral region of the maxilla. (control group)

The intervention is that the test group will receive four implants in the
edentulous maxilla in combination with an overdenture. The control group will
receive six implants and an overdenture.

There will be no extra risks for the patient in the procedure with four
implants compared to the standard procedure with six implants in the edentulous
maxilla. Patients have to visit us two times more for the evaluation of the
implants and the overdenture, the evaluation of the soft peri-implants tissues
and radiographic peri-implant bone height change and for the evaluation of the
patient satisfaction.