Types of Implants
During the development of implant dentistry numerous designs of various new shapes of dental implants and their subsequent use have been developed. Only a few implants though were used for a longer period of time and just a limited number of types of implants have been used up to now.
There are three categories of dental implants with different location depending on their position to the bone:
1. endosteal (intraosseous) – are implants which are inserted surgically directly into the bone
2. subperiosteal implants– are usually placed on the surface and or under periosteum, e. i. subperiosteally of the alveolar process, or of jawbone or mandible residue and are thus located just under gum tissue. In comparison with endosseal implants, subperiosteal implants are usually not located directly in the bone.
3. transosseal implants – as such, they are similar to endosteal implants. The difference is that transosseal implants penetrate through the whole bone. At the point where they come out of the bone they are fixed with components similar to nuts and washers.
Within every category there are several types of various implants which differ in shape and indication. In practice the following types are used most frequently:
Root form dental implants
These implants are currently the most popular and most frequently used implants all over the world. They are produced in many shape, size and material variations. They are considered a standard in implant dentistry. Root form dental implants can be used in case a patient is missing either one tooth or more teeth. The patient though must have sufficient bone volume; primary or after the bone expanding.
Blade implants have a longer history than Root form dental implants. Their name is derived from the similarity to the sharpness of a knife. This part of the implant – blade – is the one which is placed in the bone. They can be used in cases when the bone is too narrow for the placement of standard Root form dental implants as well as in some other cases.
Mini Dental Implants
They are used relatively rarely and their use has to be considered very carefully. They are used mainly to fix full denture prosthesis. Generally they can be put into the category of Root form dental implants but in comparison with them, mini dental implants are much thinner (having the same length). Therefore they can be used also in cases where there is not enough room for a standard Root form dental implants. They can replace single missing teeth as well.
Ramus Frame Implants
They belong to the category of endosteal implants, although they might look like subperiosteal implants. Ramus frame implants were specially designed for patients who lost all teeth in mandible. They are surgically placed exclusively to the following three locations: left and right region of the posterior part of mandible and in the area of incisors in anterior part of mandible. This way they secure a three point stabilization of mandible and thus protect the mandible from breaking.
This type of implants has the longest history in implant dentistry. Subperiosteal implants have been inserted since 1940. They are used both in total as well as in partial tooth loss. The best results however, are achieved when applied in total loss of teeth in mandible. These implants are literally custom made for every patient.
Transosseal implants are placed only to mandible. This is the only type of implant which requires hospitalization since its application requires general anesthesia. Transosseal implants are designed for patients with extensive mandible damage. The implant is inserted via bone and is fixed on the other side of the bone with a system similar to the system of ‘bolt – nut‘.
Bicortical screw is a one piece implant (root part and abutment form one unit). Like Root form dental implants, these also have a shape of a screw but their threads are sparser and deeper. Their name – bicortical – suggests they are anchored into two cortical layers – into the upper and lower layers of the bone.