Unbiased oral health information

Procedures

Dental implants

Procedure overview

Learn about the dental procedure, when it is generally prescribed, and other information which can increase your knowledge of the topic.

Alternate terms: Implants; Oral implantology; Tooth implants.

Dental implants may be thought of as replacement tooth roots. Although they are available in many shapes and sizes, depending on the specific problem to be solved, by far the most common type in use today is the "root-form" implant. Dental implants are among the most significant advancements in the history of dentistry for their versatility at replacing one tooth, several teeth—even all of the teeth.

Implants are a viable treatment option for most patients, whether one tooth, several teeth, or all the teeth have been lost, or will be lost due to a "hopeless prognosis" like the tooth shown in Figure 1.

A large cavity in this rotten molar tooth gives it a hopeless prognosis (unrestorable)

Figure 1: Decay extended into the roots of this tooth, which was given a "hopeless" prognosis. See Figures 2 and 3 to view the restored implant that was used to replace the tooth.

Implant Scenarios

Replacement of One Tooth With an Implant:

Dental X-ray of missing molar tooth replacement with dental implant supported crown

Figure 2: The "hopeless" tooth shown in Figure 1 has been replaced with a single implant, restored with a crown. Note that gums do not show up on X-ray images, so the crown appears higher above the implant in an X-ray image than in a photograph (Figure 3).

A dental implant restored with a porcelain fused to metal crown replaces tooth 19

Figure 3: A clinical view of the restored implant shown in the X-ray image in Figure 2. Note that the abutment is not visible under the crown.

Replacement of Several Teeth With Implants:

Panoramic dental X-ray shows 8 implants restored with crowns for missing teeth

Figure 4: This patient had failing fixed bridgework which she elected to replace with implants. Eight implants are present, evident from the white, threaded tooth "roots". Cases such as this may require supplemental procedures before implants can be placed, such as bone grafting to develop adequate bone volume to place implants into.

Implant Supported Dentures:

Panoramic dental X-ray shows edentulous patient with implants to support overdenture

Figure 5: This patient lost all of her teeth, and the tooth-bearing bone resorbed away so severely that she was unable to wear a traditional denture. Four implants were placed into her mandible and a gold bar was attached to them. Her denture (called an "overdenture") was then built with snap attachments to attach it to the gold bar (Figures 6 and 7).

Gold bar attached to dental implants will support lower overdenture replacement teeth

Figure 6: A gold bar attached to the implants shown in Figure 5. Note the white snaps, which will be housed in the patient's denture (Figure 7).

Dental implant supported lower overdenture and traditional removable complete upper

Figure 7: Dentures in place in the patient's mouth. The upper is a traditional removable complete denture, and is not attached to implants. The lower is attached to a gold bar, which prevents the denture from applying pressure to the mental nerves, an extremely painful condition. It also keeps the denture stable, preventing the mobility that is often caused by muscles of the tongue and floor of the mouth.

Dental implants used to support a fixed partial denture or bridge over an area with a bone defect

Figure 8: Dental implants can be used to support fixed partial dentures (or "bridges"), especially in areas of the mouth where placement of individual implants may not be possible without first undergoing a bone graft.

History of implant dentistry

There is evidence that implantation of shells into the site of a missing tooth was successfully undertaken by the Mayans as far back as 600 A.D, and may have been performed earlier in other parts of the ancient world. In their current threaded cylinder form, implants have been successfully placed and restored with excellent success since 1985. Their basic design was pioneered by a Swedish orthopedic surgeon, who was using them to study wound healing, and in 1952 established that implanted titanium would integrate into bone in a process he referred to as osseointegration. Essentially what this means is that the cells that produce bone ("osteoblasts") take up residence in the microscopic pores of the titanium surface and, over several months time, form an intricate network of bony connections to the implant, which when complete, virtually fuses the implant to the jawbone.

Based on this research, the first screw-form titanium implant like those in use today was placed into a patient in 1965. The technique was held in the research domain until twenty years later, when long-term data from human trials showing excellent success rates allowed appropriately trained dentists to begin using them routinely. Today, endosseous implants enjoy long-term success rates surpassing 95% in well selected patients.

Variations on implant placement

Variations on the type of implant to be used

There are many different kinds of root-form endosseous implants. They vary in length, diameter, degree of taper, surface treatments, method of attaching the crowns, bridges, or dentures, and anti-rotation features. Some have threads, and some do not. There are many different manufacturers, each with slight variations on these features. Your dentist will select the most appropriate type and size of implant for your needs. ToothIQ discusses only endosseous root-form implants, but other designs you may want to investigate include blade-form implants and subperiosteal implants, especially if you are missing all of your natural teeth.

Variations on the timing of placement of dental implants

There are several options for timing the placement of dental implants, as well as the restorations that attach to them. A few are discussed here.

"Traditional" (delayed) placement

The traditional timing of placement of a dental implant is four to six months after a tooth has been removed. This allows time for the tooth socket to fill in with new bone, and for the new bone to mature. Frequently, patients wait longer than six months to replace a tooth (sometimes much longer). However, as a general rule, the longer a person waits to replace a tooth, the less bone there will be to place an implant into. Sometimes it is necessary to graft additional bone into the site where the implant(s) will go and wait for that bone to integrate and mature (generally four to six months) before an implant can be placed.

The bone graft material can be autogenous (i.e. your own bone), allogenic (same species—i.e. donated human tissue), alloplastic (synthetic or inorganic), or xenoplastic (from another species, e.g. cow bone). Autogenous grafts can be taken from various places in the jaw bones, from the leg or hip, or even from the skull. Not everyone who desires an implant will require bone grafting. Your dentist(s) will determine whether you might need it.

Traditionally, an implant is placed into the bone, covered with gum tissue, and allowed to "osseointegrate" into the bone for four to six months. At that time, following traditional protocols, the implant is uncovered, and a "healing cap" that extends through the gums is inserted into the implant. Again, following traditional protocols, the implant is then restored with a crown, bridge, etc., a couple of weeks later. Your dentist can tell you whether your edentulous condition indicates traditional protocols for implant placement and restoration, or whether the timeline can be shortened at all.

"Delayed-immediate" placement

Following this protocol, a tooth is removed and the gums are allowed to heal over the tooth socket for about six weeks. This is enough time for the "hole" to be covered with soft tissue, but not enough for the bony tooth socket to fill with new bone. The idea here is that there will be gum tissue available to close the implant placement site completely. If good soft tissue closure is obtained over an implant, there is less likelihood of infection (one of the main reasons an implant can fail to integrate into the bone).

Another advantage to the delayed-immediate protocol is that the number of bone forming cells ("osteoblasts") will be greatest about six weeks after the tooth is removed. Ask your dentist whether your situation might indicate the delayed-immediate implant placement protocol, and how long it will be until the implant can be restored.

"Immediate" placement

This protocol is becoming more popular, especially for replacing front teeth that require extraction, because people generally don't want to be without a tooth or teeth in the visible "esthetic" zone any longer than necessary. Under this protocol, the tooth is removed and an implant is immediately placed into the extraction site. It may be necessary to graft bone around the implant, and in most cases, there is no ability to close the gum tissue over the implant. If certain conditions are present, it may also be possible to place an immediate temporary crown on the immediate implant.

In those cases, the patient never goes without a tooth, and doesn't require a temporary denture of any kind. Ask your dentist whether your situation might favor this technique, with the understanding that it may come with some additional risk of not integrating into the bone properly. Many dentists charge more for immediate restoration of immediate implants due to the greater risk.

More examples of dental implant treatment

Photo of dental implant restored with porcelain crown to replace missing tooth 10

Figure 9: This patient was missing her upper lateral incisor since birth. An implant was placed and restored with the crown shown in the center of this photograph. Excellent esthetic results like this require ideal bone and soft tissue contours to achieve, but are now being done routinely.

Dental periapical X-ray of implant to replace missing lateral incisor tooth

Figure 10: A periapical radiograph of the implant shown in Figure 8. Note the teeth on either side of the implant did not have to be altered in any way to achieve this result.

A dental implant restored with porcelain crown as tooth replacement for missing molar

Figure 11: A lower right six-year molar (lost to caries) has been replaced with an implant and restored with a crown. Prior to the implant being placed, the patient wore a removable partial denture that rested on the metal platform visible on the molar tooth behind the implant crown.

Implant and crown X-ray at 4 years after placement

Figure 12: A bitewing radiograph of the implant shown in Figure 10, four years after the implant was placed.

Evidence shows that dental implants are the best, most reliable, and most tooth-like treatment option for replacing missing teeth. Patient satisfaction is higher with dental implants than with other treatment options for replacing teeth, like removable partial dentures or fixed bridges. They are also the most expensive treatment option.