The most common indication for a dental implant is its use in the case of a single missing tooth. Particularly in the area of the front teeth, aesthetic expectations for this type of treatment are usually very high. Immediate implantation and restoration with a temporary crown is the most ideal solution in this area, as patients can be rehabilitated aesthetically and partially functionally very quickly. The success rate of procedures in which a dental implant is placed directly into the extraction socket does not differ significantly from procedures in which a dental implant is placed into already healed and remodelled bone. Today, of course, the term successful implantation does not only refer to good osseointegration, but also to a good aesthetic result.
Implantation immediately after tooth extraction. The dental implant is positioned too far vestibularly, which subsequently produces an unfavourable aesthetic result (the implant showing through the vestibular gingiva following resorption of the vestibular cortical bone).
When placing a dental implant in the gap of a single missing tooth, the height of the interdental gingiva (papilla) is determined by the attachment of the gingiva to the adjacent teeth. Recession of the bone and soft tissue in the anterior visible area of the implant (buccal recession), however, represents the main problem in this area. The position of the gingiva in this area naturally depends on the position and shape of the supporting bone. All efforts of the clinician placing the dental implant are therefore directed towards preserving the bone surrounding the tooth and, subsequently, the dental implant on the anterior visible side (buccal cortical bone).
The thin bony wall that surrounds the root before extraction consists of harder bone (cortical bone) or bundle bone. After extraction, this bony wall loses its physiological function (the tooth is no longer present) and therefore gradually disappears. If a surgical technique involving elevation of a mucoperiosteal flap is used, the blood supply to this part of the bone is interrupted and relatively extensive resorption of the buccal cortical bone occurs in every case. It is therefore important to perform the procedure without flap elevation. It is also essential to achieve sufficient primary stability of the dental implant, which is ensured by preparing the implant bed beyond the fundus of the alveolus, or beyond the apex of the previously extracted root.
Regardless of the factors already described, the position of the dental implant is important for the final, including aesthetic, success. Particularly in the buccopalatal direction, the dental implant should have a precisely defined position. A dental implant positioned too far vestibularly causes even faster resorption of the vestibular cortical bone and, consequently, later visibility of the implant through the gingiva. A dental implant positioned too far palatally causes subsequent problems when shaping the artificial dental crown, which must have a bulbous shape, making proper cleaning of the contact area between the gingiva and the crown impossible. The dental implant should be positioned 1 mm behind the line connecting the most vestibular points of the adjacent teeth.
Immediate implantation after tooth removal does not itself influence greater or lesser resorption of the vestibular bone, which otherwise has the greatest impact on the aesthetic result. There are many studies that support, or do not support, implantation together with bone augmentation, which is intended to reduce resorption of this part of the bone. The gap between the implant and the alveolar cortical bone should be filled with a slowly resorbing xenograft, which is intended to stabilise the blood clot and thereby reduce resorption.
The first step in fabricating a temporary crown that can be mounted on a directly placed dental implant is to record the position of the implant. In this case, we do not use conventional impression-taking, as this can increase the risk of infection in the surgical area. The impression abutment or transfer post is connected to the adjacent teeth using composite material. The construction is removed from the mouth and transferred to a previously prepared study model, which is hollowed out in the area of the extracted tooth. The laboratory analogue can then be inserted and fixed in the model. On such a model, the dental technician prepares a temporary superstructure, which can be mounted on the inserted dental implant relatively shortly after surgery. The main objective of the temporary restoration is to shape the soft peri-implant tissues so that, ideally, they correspond to the shape of the extracted tooth. For this purpose, the best option for a temporary replacement is naturally to use the crown of the extracted tooth. If this is not possible, acrylic provisional restorations are used, preferably on titanium supports, which later serve as permanent abutments.
