Pre-Surgical CAD/CAM planning of implant treatment in order to restore fully edentulous mandible/maxilla

The modern prosthetic rehabilitation of edentulous patients is a complex
treatment. The input of different specialists and sub-specialists such as
dental implant surgeons and prosthodontists is necessary and very important to
treat these kind of patients correctly.
Since the introduction of dental implants, there are different new
possibilities to treat these kinds of patients. According the original protocol
the implants were loaded after a healing period of 3 to 6 months, so called
delayed loading.
The changes in implant*s architecture and the implant*s surface structure have
resulted in decreasing the osseointegration period and the healing time
considerably.
So-called immediate loading has found its intro in implant dentistry.
According to different research reports from various academic centres we can
conclude that, when dealing with edentulous patients, the success of the loaded
implants is independent to the loading protocol. Another very important
evolution in prosthetic dentistry is undoubtedly the introduction of CAD/CAM
technology. CAD (Computer Aided Design) and CAM (Computer Aided Manufacturing)
is a progressing technology which, based on digital radiographic images, can be
used for both planning and manufacturing of the prosthetic and surgical
instruments in a precise maner.
The CAD/CAM aided treatments in dentistry are based on digital CT-scan. These
images are converted in specified format, Dicom.
With the help of the computer software we can covert the images to a 3D model
of the treated jaw.
Hereafter we can virtually plan the case by placing the implants in the ideal
positions considering the different anatomic structures and obstacles. The
same data can be used to design and plan the prosthetic solutions using
CAD-software, which will be fabricated according the CAM-milling devices.
To transfer the information from the computer to the patient we need to work
with references. Unfortunately there is a lack of references in edentulous
patients. To solve this important problem we create some reference points by
inserting mini-implants prior to the actual surgery.
These implants remain in placed during the complete treatment period. They will
be used in every diagnostic, prosthetic and surgical procedure, which increases
the exactitude of the treatments considerably.
The gathered data can be processed after the finalising the radiographic
research. The dicom data can be loaded into the specially designed computer
software, which can create in a very precise manner a 3D model of the treated
jaw.
Now after the finalisation of the planning we can start designing the drilling
guide and the future superstructure. These designs can be loaded back to the
planning software for the final check where after the CAM-fabrication can
start.
The fabricated superstructure will be finished at the dental lab and will be
provided at the same time as the surgery.
Using the 3 mini-implants, we can connect the surgical guide in a very stable
way. Now, the surgeon is able to precede the surgery in an exact maner where
the drilling guide dictates the surgery as it was planned in our virtual model
without damaging delicate anatomical structures like for instance nerves.
Directly after surgery we can install the final prosthesis in place.
That gives us several advantages:
* The freedom for the patient to receive the final prosthesis immediately
after the surgery
* Less complications because of the flapless surgery
* Full mouth reconstruction involves less chair side time and patient visits
* Precise treatment where the chance of damaging vital structures is minimal
* Trans-arch implant connection improves the osseointergration (according to
many recent studies)

A 3D virtual model of the treated jaw gives us the opportunity to design and
fabricate the surgical guide and the final superstructure.
Some companies have already introduced this kind of treatment to the market.
The main difference with our research protocol is, in the protocols used up
till now, the lack of reference points, resulting in the removable guides and
decreasing the reliability of the treatment.
The three reference implants, a technical improvement of pre-existing CAD/CAM
technology, have resulted in a more precise and compact treatment protocol.
How exact this virtual model is in reality has not yet been determined.
The difference in the exact fit of the CAD/CAM designed superstructures versus
traditional impression technique has not yet been determined.
Moreover, the effect of the possible misfit on osseointegration or healing of
the dental implants is not completely clear.
Is it possible that a minor misfit can result in a faster and better
osseointegration?
We hope to find the answers to these questions.

The patients are adult male or females older than 25 years of age with
edentulous upper and/or lower jaws. All the patients will be selected according
to the inclusion and exclusion criteria mentioned in the research protocol.
Each jaw will be treated with tree mini-implants. Thereafter the various steps
toward a full denture will be taken.
The optimal denture setup will be copied with barium sulphate contained resin
to become the so-called CT-denture. Ct-denture will be inserted on the
mini-implants at time of radiographic recording.
The images will be translated and imported in the special software and the
processed to 3D virtual model.
On the planning software we can virtually plan the surgery bringing the implant
in the ideal position with regard to the available bone quality and quantity
and the future prosthetic needs when considering different anatomical
structures.
The planning data in turn will be imported into the designing software (CAD)
where the drilling guide and the superstructure will be designed.
The complete design and planning will be dubble checked in our planning
software before sent to the milling devices (CAM). The milling is executed by
simultaneous 5-axes milling machinery.
The milled frame will be delivered to the dental lab that will take the
necessary steps to finish the final superstructure according the existing
master model.
At the time of the surgery we connect the drilling guide to the mini-implants,
giving us the absolute stability. Surgery will be preceded according to the
flapless protocol giving the patient minimal discomfort after the surgery.
Immediately after the surgery, the final prosthesis will be placed directly on
the implants giving the patient immediate aesthetics and function.
At the end the reference implants will be removed.

0