Dental implants are used when it's necessary to replace at least one tooth in your mouth. The implant is actually a titanium post that gets surgically installed in your jawbone, so as to provide an anchor for an artificial tooth that will be emplaced. The implant actually takes the place of your tooth root, and serves the same anchoring role. Because an implant must be installed in the jawbone, it will be necessary to have sufficient jawbone to carry out the procedure.
If you've had a missing tooth for quite a while, it's possible that part of your jawbone has undergone resorption, and has shrunken in size. Even if this happens, it may still be possible to install implants, because jawbone grafting can build up the jawbone again, and make it suitable for fusion with an implant. In the case of all-on-4 and all-on-6 implants, multiple teeth are being replaced, and it's usually an entire upper or lower arch of teeth.
Whereas normally it would be necessary to install one implant for each missing tooth, it is possible with either all-on-4 or all-on-6 to replace all the teeth on top or bottom by only using either four or six implants. Below, you'll find some more information about both these techniques, so you can make an informed decision about which one might be more suitable for your circumstances.
When you have to replace all the teeth on the upper or lower part of your jaw, you'll probably think of all-on-four dental implants first. Of course, dentures will also be an option, but they're not nearly as solid as all-on-four implants which are anchored right into your jawbone. There's something to be said for the longevity of dental implants, since they will often last the entire lifetime of someone who has them installed. With all-on-four dental implants, there are four titanium posts inserted into the jawbone and the rest of the dental appliance is attached to those four small rods.
Either the upper or lower teeth can be replaced as a permanent solution, and once it's in place it's seldom necessary to remove it or tinker with it. This is an ideal solution for individuals who have lost all their teeth or whose teeth are badly deteriorated. Even if you don't have enough jawbone to support the four dental implants, you can undergo bone grafting which will build up your jawbone, so it's suitable for fusing with the titanium posts.
All-on-6 dental implants are very similar to their cousins, the all-on-four implants, the obvious difference being two extra implants are inserted per arch. The reason for this is to provide further stability to the hybrid denture which will be placed over it. In some cases, it's not advisable to use the all-on-four implants approach, because it won't provide sufficient stability in the patient's mouth. In situations like this, all-on-6 implants are a better option.
Just like the all-on-four implants, these implants will fuse with your jawbone over the course of several months, and after that they will be just like the natural roots of your teeth. An upper or lower arch will be affixed to the six implants, and you will be provided with a set of replacement teeth that is permanent in nature. If you're missing all of your teeth, or if you plan to have all your teeth removed, all-on-6 is a viable option for all those people who may not be able to get by with the all-on-four approach. In either case, you will end up with a permanent solution that will allow you to eat, chew, and smile in a completely normal fashion.
As you might expect, there are quite a few similarities between these two approaches, although one exception is that two extra implants are necessary for further stability in the all-on-six approach. Both of these procedures solve the same kind of problem, which is providing a permanent tooth replacement option which is extremely stable, and can be expected to last for many years. Even though there are a great many similarities between the two processes, there are also several notable differences.
All-on-6 is generally used on patients who have fairly long arches, and that would make it difficult for just four implants to do the job. It's possible that fracturing and breaking of the dental appliance would occur in the aftermath of this instability. It won't come as a surprise that the all-on-six procedure is more expensive than the all-on-four process, simply because two more titanium posts have to be installed.
It's also true that the all-on-four approach requires dental implants that are slightly angled. This removes some of the cantilever effect, and prevents breakage of the hybrid denture. The all-on-six installation requires parallel implants, and the cantilever effect is reduced because there are two extra implants placed towards the back of the jaw. This will reduce the possibility of fracturing in the same way that the angled implants of the all on four process.