Continuing the creation of the F. A. Q. for dental implants, it is time to move on to what, in fact, we have to implement titanium “screws”. That is, directly to the ultimate goal of any implantological patient for prosthetics. The structures that are built by orthopedic dentists based on implants are very diverse. This branch of dentistry is developing so rapidly that the number of various materials and technologies is growing every day. And many of them immediately start working in the hands of the most advanced doctors. We will try to understand the most basic questions.
What is an abutment?
An abutment is an adapter head that is screwed to the implant, and on which the crown (or any other prosthetic structure) is placed on top. Each implant system has its own set of different standard abutments. The greater the choice of different configurations and sizes of abutments, the easier it is for the orthopedic doctor to solve any clinical situation. Expensive popular systems have a wide range of these important spare parts, which is called, for all occasions. And so they are better. Therefore, the choice of the implant system is often made by the doctor based on what opportunities for prosthetics are provided by a particular manufacturer. Equally important is the degree of accuracy and reliability of the connection between the abutment and the implant. This is like a constructor, the details of which must be perfectly matched to each other. The service life of the entire structure depends on this in many ways. And here, as a rule, the simpler and more budget-friendly the system, the more flaws and design inconsistencies it meets.
What is the difference between an individual abutment and a standard one?
As the name implies, in the first case, the abutment is carried out individually in a single copy and has a strictly necessary form for a particular case. In the second case, we are dealing with a factory stamped product.Standard titanium abutment installed in the oral cavity. This standard “cylinder” does not repeat the shape of a real tooth, does not support the correct shape of the gums. In addition, when the crown is fixed to such an abutment, excess cement can easily penetrate deep into the gap between it and the gum. The individual zirconium abutment is made strictly according to the desired shape, which is usually what the Central incisor should have. The gum is well supported. Space for” numb ” cement deep under the gums is not.The left crown is made for an individual abutment, the right for a standard one. The difference in form is obvious. The first one has a more correct, natural profile.
What is better and is there a difference for the patient? Imagine that you come to a Shoe store and find the model you like. Everything would be fine, but only fashion shoes of certain sizes are produced, say, 37, 39, 41 and 43. And You have as on evil 40 th. Ah, so-poorly can be take 41 th and wear beloved shoes-stilettos, poddevaya woolen sock. So, unsightly… but they don’t die of it, do they?! But if you ate a lot of Rastishka as a child and your feet were swollen exactly 50th? No extra socks will help. And this is only a rough comparison. Because the size of something You may be fortunately ravnagora 39th. And here is, like shoes dressed, but comfort you would still not feel… in the foot, it presses in width, and in the rise, on the contrary, everything somehow hangs out… In General, kind of fit, but uncomfortable. And now, in contrast to this, imagine that your shoes will be made to order for Your foot, taking into account all its features. In these shoes, even on a 10-centimeter heel, you will feel like in Slippers. That’s about all the same can be said about the differences between standard and individual abutments. For jobs that don’t claim to be high-class, especially in terms of aesthetics, in austerity mode, you can do with standard ones. Well, for example, on chewing teeth. If we are talking about maximum aesthetics and service life, then individual ones are the best choice. I must say that at the dawn of implantology, the price difference between factory-made and individually made abutments was significant. Today, with the advent of an increasing number of CAD/CAM * systems, the cost of producing individual abutments from all materials (primarily titanium and zirconium) has actually equaled the cost of standard factory abutments.
What is the difference between screw fixation of crowns on implants and cement fixation? what is better?
First of all, we need to explain that during cement fixation, we have an implant to which the abutment is screwed with a screw, and already a crown is placed on top of it on the cement, in fact, in the same way as on your native tooth. With screw fixation, a crown is made immediately, which is fixed directly to the implant (without an abutment) with the same screw. In this case, the screw hole remains in the crown, which is closed with a conventional light filling material.
What’s better? This question is similar to what is better Mercedes or BMW, Canon or Nikon, Mac OS or Windows, Gucci or Prada… it is not necessary to contrast one type of fixation of prostheses with another. Although among very advanced dentists there are ardent fans of this or that method that defend their position on better use of one technique over another. In fact, in my opinion, both of them have an equal right to life and selective application in certain conditions. Each has its pros and cons. And I believe that in this matter, the choice is for a specific doctor. If he justified his choice to you, and you internally agree with his arguments, then just trust. Otherwise, you can get to the point that the implantologist’s advice during the implantation operation is how to hold the tip correctly, which Drills to choose, which thread to sew, etc.in General, this usually happens only with one type of patient… by the dentists themselves, when they find themselves on the other side of the boron machine.
And yet, if such a question has arisen, then for particularly interested patients, I will explain very briefly the disadvantages of each method of fixation.
Screw fixation of crowns to implants.
There is always a hole on the crown that has to be closed with a composite. Aesthetics suffer from this. In addition, the opening of the screw shaft may come on a hillock, the cutting edge (in these areas, frequent chipping is possible and closes the” hole ” of the composite) or the front surface of the front teeth (in this case, there will be a clear failure in aesthetics).
With long bridges supported by implants, even with small inaccuracies in the frames (which happens in our life, in General, often), screw fixation can give the doctor a false sense of confidence that everything is working as it should, without gaps.” In fact, by “pulling” the crown frame to the implants, the doctor concentrates a lot of stress on the fixing screws and then unpleasant problems are possible. For example, a screw may simply burst. And getting it out of the implant later is a big problem. All this can end very sadly, up to the need to remove the “screw” with a fragment of the fixing screw inside.
In this diagram: 1-implant, 2-abutment / crown, 3-fixing screw. The red arrow shows the location of the fixing screw inside the implant during screw fixation. Blue-a possible fracture of the screw when tightening an inaccurately manufactured structure and, as a result, the concentration of excess stress on the screw.
Cement fixation of crowns to implants.
One of the main drawbacks is that excess cement that is squeezed out when the crown is fixed can get a thin film deep enough between the gum and the abutment. And this is one of the possible causes of peri-implantitis-inflammation of the bone tissue around the implant. When this process is started, it is not so easy to stop it, and everything can end with the loss of the implant. And with it, bone tissue to replace it with a new one.
This photo shows the crown fixed to the abutment using cement. The arrow shows a film of frozen cement, which can cause inflammation around the implant-perimplantitis.
If the crown frame does not fit very precisely to the abutment, the fixing cement may eventually be eroded by saliva. The resulting gap will begin to fill with soft plaque and oral bacteria. In the best case, this will result in easily correctable cementation and loss of the crown. In the worst-again, there is a basis for the development of pamplonita.
Sagittarians are Shown the gaps between the crown and the abutment. If such a crown is cemented, after a while these cracks will become a place for storing soft plaque.
In fact, all of these disadvantages of both methods are easy for the doctor to get around. So let’s hope that You will get just such an orthopedist, and You will not have a headache from such a specific issue as the choice of how to fix the crown on the implant.
Can I put Bridges on implants?
Yes. This happens all the time. Not always from a good life, but still there is nothing wrong with this design on implants. In some cases, this may even be the most rational option than natikannya “screws” in place of each missing tooth. Moreover, it is quite possible to make so-called consoles on implants in some situations-that is, suspended teeth with support only on one side. This is something that is strictly undesirable to do on our native teeth, but sometimes under certain conditions it is permissible on implants. But, of course, this does not mean that you can put a pair of implants on the edges of the jaw in the absence of all the teeth and stretch the bridge “from ear to ear” in 14 units on them.
Here I will make a small digression about toothless jaws. If we are talking about prosthetics on implants with fixed bridges already “bald”, like the knee, the jaw, then the minimum need to put at least 6 implants-supports. And better 8 or even 10. The more supports there are, the less vulnerable the structure will be over time and easier to maintain, both for You and the dentist. For example, with 8 or 10 supports, a large single bridge for the entire jaw can be divided into several (2 or 3) separate ones. This will give an advantage in facilitating hygiene procedures, and in easier subsequent repairs (if necessary). In addition, according to many studies, it is generally very undesirable to make a single unbroken bridge “from ear to ear”on the lower jaw. The fact that it looks exactly like a horseshoe (and that’s what it’s called in professional slang) is unlikely to bring you luck. But here’s the problem-it probably is.
A single metal-ceramic bridge to the lower jaw with support for 8 implants.
This will end with a “toothless” departure from the main issue.
What is wrong with any bridge? Most importantly, it complicates hygiene. All crowns are connected in a monolithic structure, access to implants for thorough cleaning (and this is very important for their long service life) is difficult. Of course, today there are many devices for maniacs (in a good sense) oral hygiene-irrigators, special Brushes, superflosses, etc. But, hand on heart, how many of us pay enough attention to this issue in the daily bustle? To this still need add, that in the future under any problems about one of implants (3 times poplyuem, of course, but removed any case) sack will have immediately all United in bridge crowns. And this, you will agree, again considerable expenses for their replacement.
Sum up … Choosing the number of implants in the absence of several teeth at once is not fun for the patient. This should only be done by the dentist, evaluating a large number of factors. You just need to properly weigh all the arguments of your doctor, along the way mentioning some of the nuances described above.
If your teeth are no longer on the jaw, what is the most affordable option for prosthetics with implants? Prosthetics on suckers” I don’t want to wear.
Just above, I have already told you that to make a fixed prosthesis on a toothless jaw, you need to put at least 6 implants. This, of course, is not the most budget option. If you take a smaller number of implants, the prosthetics will be removable in any case. What are the basic options here?
When installing 2 implants (usually in the positions of former canines), the orthopedic doctor can only make a normal full removable prosthesis. Abutments are installed in implants (most often in the form of balls), and locks are welded into the prosthesis according to them. The only advantage of implantation in this case is that the prosthesis will still be clearly fixed on the jaw, and it will not have to constantly “catch” when chewing and talking. That is, the comfort of using the prosthesis will increase many times. This option of prosthetics is well suited to elderly patients, because it is the cheapest. In addition, even in the case of severe bone atrophy, it is usually always possible to put a pair of implants without any unnecessary difficulties in the form of bone grafting and other traumatic and expensive preparatory surgical measures.
The upper photo shows special abutments for fixing the removable prosthesis, installed on 2 implants. On the lower one there is a removable prosthesis with locks, which are quite firmly fixed on the abutments in the oral cavity.
If the patient wants the removable prosthesis to be fixed even better on the jaw, and even take up as little space as possible in the mouth, then the number of implants installed will have to be increased to 4. In this case, a metal beam is fixed between the abutments, for which the prosthesis is even more firmly held.
And even during active use of the prosthesis, it will be almost impossible to reset it. An additional bonus in this case is to reduce the base of the removable prosthesis, leaving more free space in the mouth for the tongue (if it is the lower jaw) or on the palate (if it is the upper jaw). The patient’s comfort from this will definitely be significantly increased.
Clinical case: advantages of individual abutments
The development of modern CAD/ CAM * systems for manufacturing various structures has made the procedure for manufacturing individual abutments quite accessible. Not so long ago, an individual Zirconia abutment was not available for every implant system, mainly for the “top” ones (Nobel, Astra Tech). Therefore, it was expensive, it was made for a long time, and, as a result, such prosthetics were not so affordable. Already today, the situation has changed radically. Not only is it now possible to produce individual abutments not only for the most expensive implantation systems (such as Alpha-Bio, MIS), but the cost and timing of production have made individual zirconium abutments absolutely available for mass use. In fact, for the patient, the price of prosthetics of 1 tooth according to the “top” implant + standard titanium abutment + metal-ceramic crown was equal to the price of prosthetics according to the “netopoviy” implant + individual zirconium abutment + metal-free crown. What is better in this case? Answer below.
How is an individual Zirconia abutment better than a standard titanium abutment?
Its most important advantage is its complete anatomy and individuality. This is not only important from an aesthetic point of view, but also allows you to avoid getting the fixing cement under the gum when fixing the crown to the abutment. This is a very important plus, because the imperceptible penetration of even a thin film of cement between the standard abutment and the gum, which can cause inflammation after a while-perimlantit. It is extremely difficult to treat it, and often this inflammation ends with the loss of the bone around the implant, which means that the “screw”itself.
And that’s why it happens.
Due to the fact that the standard abutment is much narrower than the crown, when the latter is fixed, excess fixing cement is literally pressed into the space between the abutment and the gum (the risk zone is marked in the figure). This situation can be aggravated by the fact that, in an effort to mask the metal of the abutment, the technician has a ledge below the level of the gum, so that the edge of the crown goes deeper and completely covers the metal abutment. This will inevitably lead to the cement getting into the zone where it will no longer be possible to remove it. The occurrence of inflammation in this case is often only a matter of time.
This is exactly the problem that happened in this situation: a ” top ” implant + a standard titanium abutment + a metal-ceramic crown instead of the lower 6th tooth.
After removal, the crown and abutment were exposed and the cement was determined to flow under the gum, which led to perimplantitis about 1.5 years after the implant was installed and to the need to remove it.
These images show the current level of bone around the implant (blue line) and the one that was originally there (red line). Here is a bone defect caused by inflammation of the tissues around the implant as a result of getting under the gum of the cement.
What does an individual abutment give us?
It is no longer just a round “stump”, but actually a full-fledged anatomical stump of the tooth. It’s as if we just processed an ordinary tooth for a crown.
In this photo, you can see the stages of prosthetics of the lower 6th tooth. It was replaced with an implant (it was installed in this clinical case by my colleague, implantologist Dr. Oleg Ponomarev). From left to right: first, the patient comes from the surgeon to the orthopedist with a gum shaper (Fig.1). When we Unscrew it, we can see the implant itself inside, in this case, the Alpha-Bio system implant (Fig.2). In order to remove the imprint, a special impression transfer is temporarily attached to the implant (Fig.3). After removing the impression, the patient is re-screwed to the gum shaper, and the casts are sent to the dental laboratory. There, The dental technician casts plaster models in a special way based on the print. The gum around the implant is modeled from special silicone to more plausibly convey the state of “natural” clear. To simulate an individual abutment of the correct shape, the Dental technician creates the desired contour by cutting the silicone gum. After that, a computer-controlled machine cuts out an individual abutment from a log of a zirconium bar of Pinocchio.
Thus, the individual zirconium abutment is almost identical to the “natural” neighbor prepared for the crown. After 7-10 days, the technical work (individual cyroknia abutment and whole-Zirconia crown) is completely ready, and we can fix it in the mouth. Before screwing the individual abutment, the gum around the implant is pre-adjusted slightly. In the same way, as did the techniques on the model.
Then you can fasten the abutment to the implant. Notice how white the gums around the abutment are. This means that it is very tight to it, and when fixing the crown, excess cement will not be able to flow there if desired. It is impossible to achieve the same tight fit of the standard abutment to the gums with all the desire.
And here is the final result. Whole-Zirconia crowns were made for the Alpha-Bio implant and your own tooth.
In all aspects, this design wins over a pair of standard titanium abutment + metal-ceramic crown. At the same time, the price of a standard metal spare part from a” cool ” implatant system is actually equal to the cost of producing such an individual abutment from zirconium. What to choose? The question, in my opinion, is now rhetorical. And metal-ceramic crowns now have a better and comparable price alternative.
So I advise both doctors and patients to perform prosthetics on implants only on individual spare parts. This is much more predictable and will give a good and long-lasting result. And this is usually what dentists themselves want, and even more so, our patients!