Types of Dental Implants
Types of Dental Implants
There are many different dental implant types available, each one designed to meet specific patient needs. After a thorough evaluation the dentist will recommend the most suitable type of dental implant for each case, depending on the purpose of the treatment and the condition of the periodontal tissues of the specific patient.
Dental implant types can be categorized in different ways:
Types of Dental Implants - by placement type
The first categorization of dental implant types is based on the way the dental implant is placed and anchored to the jaw bone. Depending on the condition of the jaw bone the placement of the dental implant can be done in the bone, on the bone or through the jaw bone.
- Endosteal or endosseous implants
Endosteal (in the bone) implants is the most commonly used type of implants. They are surgically placed directly into the jawbone to substitute the root one or more missing teeth supporting a crown, an implant bridge or an implant supported denture. Endosseous implants can be either root form of various widths or plate shaped, placed in a one or two-phase procedure.
- Subperiosteal implants
Subperiosteal (on the bone) implants consist of a wide metal framework placed on top of the jawbone below the gum tissue, with attached metal posts protruding through the gums waiting for the mounting of the restorations. This type of implants is used when there is not enough jaw bone width or height to withstand the placement of an endosseous implant due to bone resorption. In these cases the patient is unable to wear conventional dentures.
Subperiosteal implants are more expensive than endosteal ones because they have to be custom made for each patient after taking impressions of the jaw or by use of CAT scans. Placement is done with a 'single surgery' method if CAT scans and advanced computer modeling techniques, are used to create the model of the jawbone that the dental laboratory will use to fabricate the custom-fit subperiosteal implant. Otherwise, placement is done in a 'dual surgery' method, one to expose the jawbone and get the impression that will be sent to the lab and a second one to finally place the implant.
- Transosseous implants
This type of implants is rarely used today due to the extensive surgery, general anesthesia and hospitalization required. Transosseous implants were developed for patients with very limited bone structure. They can be used only for the lower jaw and surgery involves inserting two metal rods from below the chin, through the jaw bone, until they are exposed inside the mouth where they are used to attach the denture. The wider use of bone grafts by dental implant dentists today has made possible the use of alternative types such as endosseous or subperiosteal implants that do not need such extensive surgery.
Your dentist will decide which type of implant to use based on the quality of the bone in your jaw and the type of crown, bridge or denture that will be placed on the implant.
Types of Endosseous Implants
Besides the well known screw-like dental implants, there are two more forms that are also placed into the bone. The endosseous dental implants include the following types:
- Root-Form Implants
Root-form implants are the most common and popular among all types of dental implants. They are usually cone or screw like implants, resembling the shape of the natural tooth root, which are designed to be surgically placed inside the jawbone. Root-form implants can be used to provide a base for restoring one, several or a complete arch of teeth, only if the jaw bone has adequate width, height and structural integrity. Dental bone grafting is commonly used to make possible the use of endosteal root form implants. and come in various widths and lengths.
- Plate-Form Implants
Plate form implants also known as blade form implants are a less common type of dental implants, used when the jaw bone is too narrow for root form implants and the area is not suitable for bone grafting. They consist of a flat and long metal square with one or two metal prongs on one side. Plate form implants are surgically placed vertically in the narrow jaw with the prongs facing into the mouth providing an anchor for the placement of the restorations.
- Ramus Frame Implants
The Ramus Frame Implant is a special type of endosseous blade form implants used for patients who have suffered severe bone deterioration in the lower jaw and have problem with the fitting of their dentures. A Ramus-frame implant consists of a thin metal bar that extends across the jaw, embedded in the jawbone in the back corners of the mouth (near the wisdom teeth) and also in the front side of the jaw near the chin. The Ramus frame type of dental implants is used to secure dentures on thin lower jaws.
Types of Dental Implants - by treatment procedure stages
Another common way to categorize dental implant procedures is by the number of surgical treatment stages needed for the placement of the implant:
- Two-stage dental implants: This is the most common type of dental implants. During the first surgical phase, the dental implant is placed into the jaw bone so that its top surface is at the same level of the bone. The gums are then stitched to fully cover the implant. The dentist will wait a few months for the implant to osseointegrate properly with the jawbone. Then during the second surgical phase, the dentist will make a small incision to the gum tissue to expose the top of the tooth implant and connect a dental implant abutment. After the gums have healed, the implant is ready for the placement of the final restoration either a crown, bridge or denture.
- one-stage dental implants:
This type of dental implants has been developed during the recent years and gives dentists the opportunity to provide patients with much shorter in time implant treatments.
The major difference of one-stage implants is that during the first and final surgical procedure, a longer type of implant is placed in the jaw bone in such a way that the top of the implant is higher than the surface of the bone.
When the gum tissue is stitched up the top of the dental implant (head) is not covered under the gums but remains exposed and visible.
After the healing / osseointegration period there is no need for a second surgery for exposing the head of the implant because it is already exposed.
The dentist only needs to connect the dental implant abutment and can start the restoration process immediately.
Mini dental implants are also one-stage implants because they come in one piece with the abutment already fixed on the post.
- Immediate Loading Implants: one-stage implants should not be confused with the immediate loading implants usually advertised as one-day implants, instant or immediate implants, Teeth-in-an-Hour etc. Immediate load implants are not only placed in one surgical stage but also the restoration can be placed almost immediately. With immediate loading implants the patient can avoid the long waiting period for the osseointegration process to be completed, but they are not always suitable for all cases.
Both dental implant types have similar success rates and it is usually up to the dentist to decide which type of dental implants to use based usually on his experience with each of the dental implant types.