Dental Implants

Last week the All on 4 case brought some interesting challenges. One of the primary benefits of the All on Four procedure is the ability to give most people dental implants and a new set of non-removable teeth all in the same day without preliminary bone development with grafting. Hence the All on 4 technique is becoming more and more popular as well as seamless.

Fortunately for those who do require grafting there are new techniques and materials that dramatically simplify the All on 4 procedure and improve predictability. Recently I discussed two new players, bone morphogenic protein and stem cells. Both can now be synthesized in the lab and I use both frequently for the All on 4 treatment with great success.

A Problem That Can Delay the All on 4 Procedure

In the last couple of weeks I’ve seen three grafting cases that were having varying levels of complications. All three were developing infections because the gum tissue had developed an ulcer over the grafted area. An ulcer of this nature is referred to as a membrane exposure and it could lead to a catastrophic failure of the graft requiring it to be redone and delaying the All on 4 procedure by several months.

About Osseous Grafting – Preliminary Preparation for All On 4

Here’s a little background on osseous grafting to help this make sense. You may consider it as one of the most delicate as well as crucial part of the All on 4 procedure. Hence it is important to share the vital preliminary preparation process of the All on 4 dental implant technique. Imagine that for simplicity we are working with bone covered with skin “gums.” We want to expand the volume of the bone. An incision is made in the gums and they are teased back exposing the bone. Pinhole bleeding points are made in the bone to supply nutrition and a layer of bone growing material is layered over the bone.

These materials have a consistency a little like sand mixed with honey so something has to be placed to maintain the desired shape. What is placed over the graft is called a membrane and the two most common are titanium mesh and titanium reinforced Teflon. The mesh is like a window screen and the Teflon is like plastic with small wires in it. Both can be shaped as desired and placed over the graft. Their purpose is to maintain the proper space for the bone to grow in. These membranes are then secured with bone tacks or screws so they will not move while the bone growth occurs and the gums are sutured back into place over the membrane. This is the base foundation to proceed with the All on 4 dental implant process.

The trickiest part of this is keeping the gum tissue healthy over the membrane because in nature the gums and bone are in intimate contact and in this scenario the gums and bone are intentionally kept apart. This interrupts normal blood flow and consequently encourages ulceration of the tissue. Once ulceration occurs the membrane is exposed to germs in the mouth and infection becomes likely, which is not at all a favorable condition to carry-on with the All on 4 treatment process.

Proper surgical technique minimizes the risk of membrane exposure but even with the most experienced surgeons it happens almost half of the time within 4 months, often within 4 weeks, and sometimes almost immediately. The key is to control or prevent the infection once exposure occurs so the membrane can remain as long as possible. Removal of the membrane stops the infection almost immediately but premature removal can doom the growth of bone.

The Three Current All On 4 Dental Implants Cases

Now with that background let’s return to the three recent cases. One was discovered at 2 months, one at 4 months and one at 5. Though all patients are counseled extensively about this possibility none of these patients brought this to my attention highlighting how difficult it is for the average patient to recognize the problem. All three were discovered at routine post operative exams or oral hygiene [cleaning] visits. All three patients already had infections and were placed on broad spectrum antibiotics and the ulcers were rinsed out with an antibiotic solution. Each stopped draining within a week and the 4 and 5 month membranes were removed a week later. Both sites had excellent bone regeneration (great base for the All on 4 procedure) though it was still a little immature.

I placed the implants for both patients but as the bone was still soft I could not place them tightly enough to build teeth on them immediately. I will wait 6 months for absolute integration of the bone and implant and then these patients will have the set of non-removable teeth that they deserve and desire.

These are delayed loading All on 4 cases as opposed to our more common immediately loaded All on 4 dental implants. The final result is exactly like an immediately loaded All on 4 case but the timing and sequence is different than the immediate load teeth in a day or smile by tonight All on 4 case.

The Expected Outcome of This Complex All On 4 Process

If I can maintain an infection free graft site around the 2 month graft with topical rinses and beneath the gums irrigation I will keep the membrane as long as possible, up to 6 months. If it requires repeated antibiotic therapy I will remove the membrane and hope that enough bone growth will have occurred to allow me to proceed with the delayed All on 4 procedure. Regardless of the immediate outcome if this patient remains committed the final outcome is certain.

We treat hundreds of All on 4 patients each year and the procedure is so predictable that we have never failed to reach our desired result. As the bone morphogenic protein and stem cell based graft materials grow bone more rapidly our outcomes when grafting is required should become even more predictable as premature membrane removal is now less of a factor.

If anything significant happens with the two month membrane I will report it in another blog. Though I hope it can be kept for 6 months it would be interesting to see what the bone looks like at 2 months. I suspect immature but adequately developed to continue maturing without further protection from a membrane making the All on 4 treatment successful. If not now sooner or later we will find out and our window of opportunity for dental implant placement will be broadened, thus making the All on 4 procedure simpler. Working in a field where new discoveries are made every day is an awesome privilege.