Dental prostheses
The tasks of dental prostheses are to replace missing teeth, to provide some kind of rehabilitation, to prevent the secondary consequences of missing teeth and, naturally, to restore the aesthetic conditions.
Dentures can be divided into two main groups. One of them is fixed, the other is removable. Sometimes the fixed and the removable elements can be combined at the same time (combined dentures). In this case the removable part must be attached to the fixed part in a hidden way.
Fixed prostheses
These prostheses are fixed to the burred teeth or the implants with special adhesives or screws, and can only be removed by the dentist.
Fixed dentures are the crowns and the bridges. If the crown of the tooth is damaged to a great extent or it cannot be retained with conserving dental methods, we usually prepare a crown. Fixed bridges are made to replace missing teeth. It is very important that already one missing tooth can cause severe problems (the contrapuntal system collides, power effects change, the tooth opposite to the missing tooth is rising, etc.) so it should be replaced. In this case the teeth around the missing one are leaning toward each other, the body itself tries to solve the problem, which does not have a result. So, the later the bridge is made, the more difficult the solution will be.
According to its material, technology and function many types of crowns and bridges exist, these days the most common is the crown with porcelain fused to metal.
Fixed prostheses can be made of the following materials
Ceramic crown or bridge bonded to a metal framework
This kind of crown has a metal frame, which reassures stability, and this frame is topped a covering layer made of porcelain, which guarantees a very aesthetic outlook. The crown protects the tooth from being broken, keeps its colour and it is very durable.
Procedure: The dentist first prepares the tooth, takes an impression of it, and then the dental technician creates the crown or the bridge. Several layers of ceramic veneer are applied to the thin metal framework, and then bonded to the framework at a high temperature. Thus, taking individual characteristics (e.g., tooth colour) into account, a natural aesthetic effect can be achieved, which is similar to the patient's own teeth. Additionally, the original masticatory function, the possibility of proper phonation and the harmony of the face can be restored with prostheses.
Ceramic crown or bridge bonded to a golden framework
Gold always has been the Rolls Royce of restorations. Even in today's competitive crown and bridge marketplace, where dentists can select from a wide range of alloys, many patients choose golden framework because of its biocompatibility, aesthetic look and durability.
The stability of the golden ceramic crown is ensured by the golden frame under a porcelain coverage. Golden metal framework fits with100% precision, therefore no gap is left between the crown and the tooth, which could be the source of a later tooth decay.
Another advantage is that the golden cap is very thin, so the porcelain cover on the frame can be thicker, which is very important for perfect aesthetic results.
Crowns made with this technique are free of all alloying or added materials, and are made of 99,8 % purity gold. This is useful information in the event of metal allergy, since the body tolerates this kind of metal very well, and allergic reactions are minimal.
The warm, yellowish colour of high-purity gold is similar to the yellowish dentin of natural teeth. As natural enamel builds upon the dentin, the technician builds porcelain similar to enamel on top of a pure golden frame. The result speaks for itself. The crown is perfectly aesthetic, natural in effect, and fulfils all aesthetic requirements.
Considering the attributes above, as well as the long-term positive experiences of our dentists, it is no wonder that we recommend golden ceramic crowns the most frequently, if there is a problem to be corrected with a crown.
• Gentle to tooth – there is no need to polish much because of the thin golden frame
• Less polish means less chance to root treatment
• 100% precision
• The golden cap provides a strong frame for the porcelain, therefore braking is not frequent
• Biocompatible material – allergy can be excluded
• Perfect aesthetic, the natural tooth can be copied perfectly
• Reliable long-term, provides first-class aesthetic results
Metal-free crowns and bridges
Metal-free veneers represent the XXI. century's technology in dentistry and they fulfill the highest aesthetic requirements. Instead of metal we make the coverages, crowns and the bases of the bridges from aluminium-oxide or zirconium-oxide ceramic, which is tooth-colored, that's why it is maximally aesthetic.
Beside the high aesthetic outlook they are ultrapunctual, that's why they have a long lifespand and they don't cause allergy.
Zirconia ceramic as a base material for crowns and bridges has been developed in the previous few years. It has numerous advantages when compared with metal-ceramic prostheses:
• It is metal-free, and does not cause allergy.
• Besides the fact that its mechanical properties are better than those of metals, a prosthesis made of it is entirely aesthetic and tooth-colored.
• It is biologically neutral (bioinert) and environmental-friendly. It conducts heat and electricity poorly; therefore, dental plaques cannot build up on its surface.
• It is permeable to light, and has excellent photodynamic properties.
• In case of crowns and bridges made of this material, there is no risk of gingivitis or premature gingival retraction.
Its disadvantage is that it is more expensive than its counterparts, however, it is more modern, and represents an aesthetically higher value. There is no risk of developing metal allergy, or a discoloration of the gingival margin near the edge of the metal parts.
Removable prostheses
These prostheses can be removed by the patient without the help of the dentist.
Partial denture
A partial prosthesis (partial denture) is used if the patient has a few teeth, but their number is not enough for a fixed dental prosthesis. This kind of prosthesis is created on a metal plate, which is covered with plastic that has the same color as the gum of the patient. The removable partial denture (the so-called metal framework) is attached to the remaining abutment teeth with clasps or hidden retainers (invisible from the outside), or onto the remaining teeth with the help of telescope crowns.
Complete denture
The creation of a complete denture becomes necessary if the patient has no teeth at all. These prostheses are kept in place by the vacuum effect. Initially, prostheses may be inconvenient to wear, but this feeling will cease. Unfortunately, because of the continuous degradation and atrophy of the toothless alveolar crest, rebasing the complete denture is necessary once in every 1 to 2 years, and replacement is required every 5 to 7 years.
Overdenture
An overdenture is a type of denture designed to go over the teeth or dental implants. It is attached by specialized dental attachments that are secured in the roots or implants. A complete set of dentures can be uncomfortable and feel unnatural, while overdentures are often a good option if the patient still has teeth roots or if the dental implantation can be carried out.
An overdenture uses instruments that fasten it to the jawbone. This procedure mimics the way that natural teeth are held in place. One type of overdenture requires the use of bar joints to support the dentures and the surrounding teeth, which often have to be adjusted to make room for the overdentures. Bars on the upper arch of the jaw need more implants than those on the lower arch because there is less bone density in the upper jaw.
Bar joint overdentures are fixed full dentures that become a permanent part of the patient’s mouth. They are screwed into overdenture implants and surgically inserted into the bone, where the denture becomes anchored. Since they are fixed firmly to the teeth, these implant overdentures make chewing and tearing of almost any type of food as easy as with regular teeth.