Teeth are out. Bone reduction is complete. And, implants have all torqued well.
Smooth sailing now.
But what the…?!
Why can’t I get that freaking abutment to fully seat in the implant housing?!
I’ve rotated it, and rotated it, and taken it in and out… but that stubborn abutment is still “loose” and will not seat completely!
If you haven’t found yourself in this position – you will at some point. I have been here on more than one occasion.
And, yes – torquing an abutment that is not fully seated will absolutely lead to implant failure. Although the abutment screw will initially torque, it will loosen with time. This will lead to a loose abutment, micro-movement and implant failure.
In order to prevent this complication, let’s take a look below at 5 unique scenarios in which difficulty can be encountered while trying to fully seat an AOX abutment. And furthermore, let’s discuss what we can do to manage these intra-operative situations when they do arise.
Why Can’t I Fully Seat My AOX Abutment?!
5 Clinical Scenarios
1. The abutment appears to seat the majority of the way, but rocks slightly and/or feels unstable.
In this scenario it is highly likely that there is some type of debris that has found its way into the inner housing of the implant body.
Most of the time this is bone debris or bone sludge created during reduction. This does not have to be a large amount of debris. This space is so small that any amount of debris will prevent the abutment from fully seating.
Forceful saline irrigation within the implant housing will remove the debris and allow for complete seating of the abutment.
2. The abutment has trouble advancing into the implant housing and resistance is felt.
This is often due to either a soft or hard tissue interference.
To avoid this, the final abutment orientation and placement (emphasis on final) should be determined prior to flap closure. This is because the surgeon has a direct line of site to both the abutment-soft tissue and abutment-bone interfaces and can confirm that there is no clinical impingement of either.
My goal is to optimize abutment orientation and placement intra-operatively and to never have to change those positions again. Confirmation of accurate abutment positions is completed before closure and prior to turning the patient over to my restorative colleague.
There is an assumption by many surgeons that the restorative provider can “change or even place the abutments” when they see the patient. While this is technically possible – it is far from ideal.
Trying to change abutments with the flap closed leads to potential soft tissue impingement. This can occur if part of the gingival tissue is caught under the abutment after an abutment position is adjusted.
Furthermore, changing an abutment to one with an increased angulation, can lead to impingement of the adjacent bone shelf depending on which way the increased angulation is oriented. This premature contact with the bone shelf will prevent the abutment from fully seating.
In both of these scenarios, the restorative provider is unable to visualize these problems as they cannot see either the abutment-soft tissue or abutment-bone interfaces. And in both of these cases, the abutment will absolutely still torque – but it won’t be fully seated. This will lead to implant failure.
3. The abutment seems to seat easily, but feels like it wobbles around.
If extremely high torque was obtained on this particular implant (far beyond the manufacturer’s recommendations), it is very likely that the inner housing of the implant has become deformed.
Typically in this case, because the inner housing has actually been widened from excess force, the abutment will fully seat but will wobble around. Even after torquing the abutment it will have some movement and will not be fixed in place.
Unfortunately, this is usually a sign that the implant needs to be removed and replaced. In order to prevent this deformation, care must then be taken not to create such high torque on the secondary implant.
*Before removing the implant – always try a new abutment to ensure there is not a manufacturing defect with the abutment you are using.
4. The abutment is torqued but appears to have some “wiggle” in the guide pin.
Tighten the guide pin, and recheck the abutment stability.
A loose guide pin will give the illusion of a loose abutment.
While this seems obvious, I’ve been in this position multiple times.
My team has handed me the abutment straight out of the packaging and it was placed successful into the implant housing, but appeared to wiggle. After checking the guide pin, it was noted that the guide pin was not actually fully tightened by the manufacturer and gave the appearance that the abutment was moving. In reality, the abutment was stable, but the guide pin itself was loose.
5. After working through all of the above, there is no rationale reason, but the abutment simply will not seat.
Always, always, always – try a new, completely different, abutment.
On a few occasions, I have come across the scenario where I cannot figure out why the abutment on hand is not seating.
After switching to a completely new abutment, the new abutment fully seated without any issue.
While this is rare, I can only conclude that the previous abutment had some type of defect that prevented it from seating.
I have literally placed thousands and thousands of abutments over the past few years. So, the reality that 2 or 3 had some type of defect, is not unlikely.
Before removing an implant due to the inability to seat an abutment, always attempt placement of a completely new abutment first. Often the simplest solution is the best solution.
While not one of the most exciting aspects of All-On-X surgery, ensuring that your abutments are fully seated prior to the restorative process is paramount to the overall success and integration of newly placed implants.
Something as small as a speck of bone debris in the wrong place, can and will derail an AOX case. So here’s to astute attention to detail for even the mundane aspects of our surgery – such as a well seated, fully engaged abutment.
Matthew Krieger DMD
P.S. Every single one of the scenarios above has happened to me on more than one occasion. If you do enough arches, you will see these occurrences as well. If not corrected, each one of these occurrences (with the exception of a loose guide pin), represents an eventual failed implant. Problem solving these intra-operative clinical scenarios is just as important as any other aspect of All-On-X Surgery.