The main purpose of prosthesis on implants is to create an ideal dental occlusion, the creation of a stable, bilaterally balanced occlusion in harmony with chewing muscles and mandibular joints.
The second goal of the prosthesis is to bring about the most satisfactory aesthetics, by which the patient returns his self-esteem and the nice smile.
Prosthetics on implants differ from the fitting on the filed natural teeth, since it requires great precision in their construction, in order to achieve good aesthetics, and this largely depends on the level of the bone and gums.
When patients have a sufficient amount of bone (vertically and horizontally), we can achieve a very good aesthetic result regardless of which implant method we use (conventional or immediate).
In prosthesis on conventional implants, good aesthetics are always obtained because a certain period of waiting for all stages of remodeling and formation of new bone around the implant is awaiting, and then impressions are made for the permanent constructions.
In cases where there is insufficient bone to place conventional implants, in order to avoid manipulations such as bone marrow augmentation, a better and easier solution is to place basal implants with an intermediate load. It is done at the same time (almost always) with extractions of sick teeth and with extirpation of cysts (periodontal and periapical). The small amount of bone, the formation of different bone levels (as a result of fresh extractions, bone plastic and gums) necessitates the creation of temporary constructions for the purpose of splinting and immediate loading to achieve an optimal aesthetic effect when replacing them with permanent structures.
Types of structures over implants
Implantation is divided in two types: early and late, depending on whether the implants are loaded at the time of implantation or at a later stage. In immediate implants fabricated structure is cemented on the 6th day, while with conventional implants this happens only after 6 months (after the period of osseointegration).
They are made for a period of 1 year (until the processes of bone remodeling are completed). They are:
1. metal-plastic: the base is made of metal, thanks to which the implants are stabilized.
The protocol is as follows: on the day of implantation impressions are taken, after 2 days the dental technician makes the metal skeleton and clinically determines the height of the bite. On the fourth day a sample is made with the selected plastic teeth and the next day the finished construction is cemented with "long time temporary" cement for a period of several months.
2. metal-composite: we have a metal skeleton base (thin, fine and light), but the teeth on it are composite, highly aesthetic and stable. The material allows re-corrections in shape and color directly into the patient's mouth as well as correction of the empty spaces that occurred after the contraction of the bone and soft tissues. This is a significant advantage over other types of temporary constructions. The protocol of operation is the same as in the above constructions, but allows corrections in the patient's mouth, even after cementation.
3. Cad-Cam technique: a relatively new method using a computer program. Intraoral scanner scans the implants directly into the oral cavity. This information is transformed into a digital code, and through special software scanned surfaces are being reconstructed. With the Cad-Cam system, a detailed plan can be made as to how future constructions would look like. The first stage of work involves scanning the objects in the oral cavity and computer image processing. The second step is adjusting and cementing the structure.
In the presence of prior teeth extractions and cyst extirpation, in bone and soft tissue plastics, soft tissue retracision and normal (physiological) atrophy of the bone are observed. After this period, permanent constructions are placed. They are:
1. metal-ceramic: the most appropriate and most preferred, classic option for prosthetics. The base is of a fine, metallic skeleton, and the aesthetic part above it is a ceramics - there is a possibility of combining several colors in order to very accurately reproduce the tooth shape and size. When ceramics are applied layer by layer, its aesthetic qualities are getting even better. For the reproduction of the gum is used ceramic in pink color - with different shades for different types of mucosa. The stages of operation are the same as for the protocol for metal-plastic and metal-composite structures. The finished constructions are fixed with permanent cement.
2. zirconium: they are non-metallic, with high aesthetic qualities, light-reflective and resemble the teeth. They have exceptional rigidity and high density. They are bioavailable and do not cause allergic reactions. They do not hold a plaque and are very easy to clean.
The material is in the form of zirconium blocks, which are milled to give whole structures or toothpicks.
3. BioHpp: a new material that is being used in imediate implantation. BioHPP is a PEEK (polyetheretherketone) based material that is already successfully applied in dental practice. It has mechanical properties similar to those of the human bone and has been used in implantation for a long time.