What is a dental implant? A dental implant is a device that is installed into the jawbone to retain a prosthesis in an edentulous patient. Now, 50 years ago, the healing of a dental implant was by a fibrous encapsulation, as what you can see here in this histologic slide. You see the black part is the implant surrounded by a connective tissue capsule and everything is in the jawbone. As a matter of fact, these fibers, they took a functional orientation and were providing like a hammock to support the implant. Now, these types of healing are no longer used today simply because this area could get infected very easily. So, what we have today is a direct bone to implant contact, which means that the implant is ankylosed, particularly anchored in the jaw bone. When we take a higher magnification, you can see that indeed, here are bone cells directly on top of the implant surface. Now, originally this osseointegration, as what it is called, was propagated or actually discovered by Per-Ingvar Brånemark from Sweden. He called this healing an osseointegration and his colleague in Switzerland, André Schröeder, also was working with this association for the study of internal fixation and developed what is called functional ankylosis. Both terms mean exactly the same. So, here you have these anchoring elements that are going to be used for anchoring over prosthesis. In 1965, when this was propagated, the fundamental prerequisites for osseointegration were a 2-stage surgery with non-loaded healing period of about 3 months in the mandible and 6 months in the maxilla. This was taken like a dogma and it was then used for a principle throughout the world. However, as time went by, these dogmas were challenged and indeed, transmucosal healing was the key feature of the healing of the more modern implants. Needless to say that those now provided a one stage type of insertion. Now, I come to some clinical indications. Where can we use implants? Basically, there are three indications. Improving subjective chewing comfort is one. Preservation of intact teeth or tooth substance, or preservation of existing reconstructions that are in full function. The third one, the third major indication is the replacement of strategically important missing teeth. Now, improving subjective chewing comfort, or chewing function, is an example in this clinical slide. You see, there is this molar that doesn't have an antagonist. And on this side there are even two molars that have no antagonists. So, needless to say, the chewing capacity goes only to the second premolar. If we now add one implant on one side and two implants on the other side, we substantially increase the chewing comfort of this patient. Therefore, we use implants to improve chewing function. Now, we can also improve chewing function in edentulous patients that have no teeth, obviously. When it is difficult to anchor a prosthesis that is maintained or stable on suction, we can add single implants here, that will improve the retention of the dentation. Now I come to the second aspect, which is the preservation of intact teeth, or reconstructions. In this image, you have a premolar, then you have a deciduous tooth, and then you have the first molar. You see there is a permanent first molar adjacent to that deciduous tooth. That deciduous tooth is not going to stay in the mouth forever, so we will lose it, as depicted in this particular slide. Now, you have two almost completely untouched teeth. If we now would bridge that gap with a fixed dental prosthesis, we would have to cut preparations on these two teeth, and that would be a pity, we would severe the integrity of the tooth. So the implant is actually the best and most biological way of replacing a single tooth. Now here you have it replaced, and you see that it blends beautifully within the dentition of that particular dentition. Now this is from the buckle aspect. You see the permanent first premolar, and the implant supported crown on the second premolar, and then the first molar. The third indication is the replacement of strategically important missing teeth. Now this lady here has very highly diseased teeth that are barely in the bone, and they will come out very easily. When we take out these two risky teeth in the front, we will have only three teeth left, and in order to construct an arch, we would need two additional strategically well placed implant abutments, which has been done here. So now we have five abutments and an arch, and on top of that, one could build a complete arch bridge. So you see implants are a blessing in the treatment planning of the treatment of the mutilated dentition. Now you see in recent years, there were a lot of discussions, and I depict you here 10 paradigms that will inherit discussion. Whether we should have 1-part versus 2-part implants, 1-stage versus 2-stage implantations, whether we should do open flap surgery versus flapless surgery, and whether we should submerge the implants or let them heal in a transmucosal non-submerged way. Should we use titanium or should we use other materials. In that respect today, we get mostly zirconia into the discussion. The machined versus moderately rough surface was for a long time a fight among the industry, and it is quite clear that the moderately rough surfaces are the ones to be used today. Screw-retained versus cement fixation is another paradigm that was discussed. Fixed dental prosthesis versus over denture, and finally, how do we prevent mucositis and peri-implantitis. Is that the result of an overload, or is it a result of the bacterial contamination? The evidence goes all towards that. Finally, the last very heavily discussed issue is of course what is the longevity of implants versus compromised teeth? As what the literature shows today, compromised teeth have at least as good a long term prognosis as implants. So implants are a blessing and here to stay, but they are not low maintenance. They are high maintenance devices and have to be kept in good shape with a patient that is worthy of having the implants in his dentition. Here is a last picture of a typical replacement of a missing canine and that missing tooth. That missing tooth now that is going to replace the central incisor, as you can see, and the canine is also missing. Now you see that both here are implants, and when we can do that with single implants, we can create an illusion close to nature. Thank you very much for your kind attention.
