Page 17 - SPRING 2016

3. Morphology of the bone: The emergence profile of the screw- 4. Esthetic or non-esthetic case: This can be complicated because
retained implant must be on the lingual or occlusal surface or there are so many variables. An implant-supported restoration
else the restoration is going to be cement-retained (Figures 4, is a replacement and we are striving for a perfect replacement;
5). Generally, the implant must be angled to make that possi- however, implant dentistry is delivered in a compromised
form one way or another. In America, arguments are being
made that we can deliver high quality esthetic cement-retained
restorations using ceramic components, soft and hard tissue
augmentations, and specially treated and designed implants
such as microgrooves, laser etching, and platform switching.
That may all be true, but I believe, when a single screw-
retained restoration is planned with the engaging type of sta-
bility, more can be achieved with esthetics than using any type
of implant system or ceramics. A screw-retained crown allows
you to have a ceramic emergence profile without a cement line
or separation anxiety between crown and an abutment if there
is recession.

Figure 4. Cement-retained #14 single crown. 5. Is it important for the clinician to be able to retrieve a case if
necessary? The advantages are obvious when there is a screw
failure or prosthetic failure. In multiple unit cases, the problem
of trying to retrieve the case becomes very stressful in terms
of mechanics, time, and finances for you as well as the patient,
even if this case is presented for a repair after years of service.
Since retrievability is important in cement-retained cases, we
try to achieve it with provisional cement and so called retriev-
able cements, but the stress remains, does it not? We are
indeed concerned about tapping an implant out while trying to
retrieve a case.

6. Are you an implant surgeon or a restorative dentist?
Communication must be more than just a referral for implant
Figure 5. Cement-retained #10 single crown.
consideration. I am a firm believer that the restorative dentist
must be the driver and not the passenger. Cases must be
worked up by the restorative dentist because whether screw or
cement-retained, implant dentistry is prosthetically driven.
Therefore, screw-retained cases become a preferential choice
by the restorative dentist, but it needs a lot more work-up than
a cement-retained case. No wonder in America, most restora-
tive dentistry is cement-retained because unless it is specifi-
cally being worked up as a hybrid case (fixed retrievable),
implants are being placed where there is more bone and so
inevitably it ends up as a cement-retained case.

If we try to treatment plan the final restoration for a single unit
case based on esthetics, maintenance requirements and complica-
tions, the engaging screw-retained restoration is the winner, hands
Figure 6. How bone morphology can dictate implant position down, in my opinion. It has the stability of an internal connection,
and, thus, the restoration choice. retrievability due to access to the screw, no worries from excess
cement, esthetic ceramic emergence, and potential cost savings as
ble. An implant placed at an angle relative to the ridge for the well. To restore an implant with a non-engaging crown does not
purpose of a screw-retained restoration, such as in Figure 6, make sense in my opinion. In most of the articles I have read for
occupies more space or a shorter implant must be placed. In the purpose of this article, I had a hard time trying to determine
some scenarios, you may place an implant more lingually, but what type of screw-retained single crown the authors were dis-
6
then, screw or cement-retained, you may end up with a lip cussing. However, it is without a doubt a decision to be made
design to achieve good esthetics. One can overcome these based on case type. 5
deficiencies by GBR before implant placement or at the time
of implant placement. In Europe, more grafting procedures are Even with guided surgery in the most experienced surgeon’s
being done simultaneously with implant placements in the hands, it is impossible to make engaging screw-retained restora-
esthetic zone. Therefore, a clinician must treatment plan a tions with multiple implants. Today we have the option of a milled
screw-retained case knowing the limitations in a given case. framework, which is 100% non-engaging screw-retained. We can
continued on page 20
www.nysagd.org | Spring 2017 | GP 17