All-on-Four Complications: Part 2


This is a continuation of The All-on-Four Complications Part 1. Again, I’m not writing this to scare you off from this treatment. I am not saying that I don’t believe in this treatment. On the contrary, I think it is a fantastic solution.

However, I would like to shed some light on some of these issues which are not regularly discussed in an open forum. By sharing these limitations, we can push past them and deliver improved treatment protocols for our patients.

(By the way, to learn how you can make All-on-Four Prosthetics & Manage common complications, see our online training courses

Hygiene Issues

Hygiene can be horrendous under these prostheses. Some patients just don’t have the manual dexterity or appropriate hygiene habits to keep these prosthetics clean. It used to be thought that calculus and plaque did not negatively affect the implants, but we know that good hygiene is necessary for good peri-implant health and longevity.

See how red the tissues are under the lingual of this prosthesis:


The intaglio surface was relieved and the patient was instructed to use Go-Between brushes as well as a Waterpik to clean under her prosthesis. I also like the brushes called “Plackers” or “Tepe Brushes” which have right angles to make posterior regions easily to clean.


This temporary All-on-4 conversion prosthesis has the worst hygiene I’ve ever seen:


It is important to ensure that the intaglio surface contacts the ridge in a rounded pin-point contact so that food does not lodge itself in there.

Questionable Implant Healing Prior to Loading

Sometimes an implant gives us some trouble before the final prosthesis is delivered. In these cases what do you do? You obviously can’t deliver a prosthesis on a potentially unstable implant. When I see an implant that exhibits peri-implant mucositis or peri-implantitis under an All-on-Four, this is what I do:

  • Treat the peri-implant infection/irritation with mechanical debridement and antibacterial protocol as indicated. (This is for another article)
  • Place another implant adjacent to this area at no additional charge
  • Allow the patient to heal up for a while longer while the new implant ossseointegrates.
  • Finally, assess the original implant and new implant before proceeding to final prosthesis.



In this next case, when I sent my case for finish, the laboratory sent me back a prosthesis with a crack at one of the access holes. This would have been bound to have caused me trouble so I sent it back for repair.


Visible Transition Line

Before placing dental implants, it is important to assess the transition line. Before implants are placed: Are the patient’s gums visible when they smile? If so, they will require a tooth-only prosthesis in order to have a natural emergence from the gums. Alternatively, the patient can have selective alveolectomy to make the gums less visible. In some situations, a prosthesis may have a very minor facial flange (emphasis on minor!) to hide this unesthetic transition. This is discussed in detail in my article on Lip Support. 


Non-Passive Fit

Passive fit is important for the longevity of the prosthesis. This patient had a screw fracture at this implant site. When a radiograph was taken, this is what I saw:


Definitely not what you want to see under your prosthetics. In residency, we would often start these cases over from scratch. However, in the real world people have more realistic expectations and are not as willing to go without teeth. In this case, the prosthesis was sectioned, the framework was laser-welded and the acrylic was repaired. The process is shown in the following pictures:

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Anterior Teeth Popping-off

When posterior support becomes compromised by wear or fracture, the anterior teeth begin to occlude harder. This commonly leads to anterior teeth popping off.


Acrylic Wear

Finally, this is one major problem we see with acrylic prosthetics. However, not all patients will end up like this. It depends on individual patient factors, specifically clenching and teeth-grinding habits. To slow this process, a night guard is absolutely, 100% necessary after All-on-4 Treatment. Another approach that I have seen is to make onlays over the molars on the All-on-4 prosthesis–but these are at risk for popping off and they may actually make the prosthesis more prone to fracture.



To learn how you can start making All-on-Four Prosthetics for your patients and how to avoid the common complications, see our training course All-on-Four “In-A-Box”.

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