Dental Implants
3I Implant
Dental Implants were first developed in Europe by Dr. Branemark in the mid-1970’s. Since the introduction of dental implants, they have gone through a transformation in shape, external and internal design, thread count and pitch, surface texture, taper and placement techniques. Dental implants have transformed the practice of dentistry giving unlimited possibilities.
Traditional 3 Unit Bridge
When a patient was missing a tooth the traditional treatment was either a bridge or partial denture or nothing! With a bridge, the dentist would have to remove good tooth structure to prepare the tooth for a crown on both sides of the missing tooth to prepare the site for a bridge. This restorative choice replaces the missing tooth at the detriment of viable tooth structure and hygiene. With a bridge, patients eventually drop flossing under the bridge and this will allow new cavities to form over time on the inner surface of the bridge. As a result, the national average life span for a bridge is 10-12 years. When the bridge fails additional tooth structure will need to be removed to remake the bridge and this often leads to endodontic or root canal therapy.
The other alternative is a partial denture. This is a prosthesis made of metal and acrylic that uses precise clasps on other teeth to help retain the partial denture. This option may be the best if you are missing multiple teeth and low cost is your primary concern. Through careful treatment planning with your restorative dentist, dental implants can change your life by restoring your smile and the chewing molars. Most people are candidates but a comprehensive consultation with Dr. Johnson and your restorative dentist will determine your best options. Dental Implants are made of titanium and resemble a drywall screw. They are placed into the upper or lower jaw and are used to place a crown or even to help support a denture. The most important criteria is bone quality and quantity. Think of bone as the concrete foundation that a home is built upon. Without adequate healthy bone or concrete, a dental implant will fail and the house will fall.
There needs to be suitable bone circumferencial and apical, or underneath, of the dental implant. Notice the picture to the right and the needed bone around the implant.
Dental Implants Mimic Your Missing Tooth
This picture also demonstrates that it is possible to remove a tooth and place an implant at the same time because the shape is similar but it requires healthy bone to support the dental implant. If the tooth had an abcess or periodontal (bone loss) disease the immediate placement of a dental implant might not be appropriate or possible. In this situation Dr. Johnson would choose to place a site preservation graft or more commonly called, socket graft. Placement of a xenograft graft (graft from another species) into an immediate extraction site accomplishes two important goals. First when a tooth is extracted the natural healing process resorbes the existing native bone, especially the bone that you can see when you smile, called the facial plate. This occurs because the tension stress that occurs while a tooth is functioning is lost. The body assumes the bone that supported the tooth is no longer needed and resorption occurs. The immediate graft will help perserve this native bone by slowing the body’s resorbtion of new native bone. The second goal the xenograft accomplishes is to stimulate bone growth into the socket which allows a dental implant to be placed sooner after the extraction, usaully within 3 months. The most common type of xenograft is bovine (cow) which is readly available and has a long history of success in the dental liturature.
Dental implants are still possible if you have have lost a tooth years ago because not all patients have the resorption that was discussed above or Dr. Johnson can perform an only graft to build the width of the alveolar bone. Onlay grafting is a technique in dental implant surgery that allows Dr. Johnson to widen the existing bone to allow an appropriate sized dental implant to be placed. Remember, a potential dental implant site needs a specific type of dental implant, one size does not fit all in implant therapy.
In some cases a sinus lift may need to be performed. The maxillary sinus is an air filled cavity within our upper jaw that is located just above the molars. As we age the sinus naturally pneumatizes, or enlarges, and when combined with an old extraction site can create a lack of bone depth. Even though implants come in a variety of lengths, from 8.5mm to 15mm long, the existing bone depth may be less. As a result Dr. Johnson may need to perform a sinus lift which places new bone into the sinus to increase the exisitng depth. Please keep in mind that any graft, including a sinus lift, needs 6 months of healing before dental implants can be placed.
The Treatment Course for Dental Implants:
Above: This patient had a bridge placed several years ago and it is now failing. The arrow shows the periapical abcess or infection with the last molar. The molar was no longer suitable for restoration and the entire bridge needed to be removed.
Above: After removing the two teeth and associated bridge, Dr. Johnson allowed the area to heal before treatment planning this case with a local restorative dentist. This patient’s choice for restoration was a removable partial or dental implants. The red arrows show the floor of the sinus, an air filled cavity, located near the area where the dental implants would be placed. As a result this patient required a sinus lift to add bone into this area to allow the proper depth to place the needed dental implants.
Above: The arrows show the outline of the sinus lift. The white screws are used to hold the gum tissue back and help widen the ridge. They are temporary and will be removed during implant placement. Once the graft surgery is complete, all patients require 6 months of healing or consolidation of the graft before we can place the implants.
Above: 6 Months later Dr. Johnson placed 4 dental implants after the local restorative dentist made a surgical guide. A surgical guide helps communication between Dr. Johnson and the restorative dentist to ensure proper placement without both doctors being present at surgery. These dental implants are properly spaced and if you compare with the second xray above would have extended into the maxillary sinus and eventually fail.
Above: Once the dental implants have integrated (the bone has grown in-between the threads) then healing abutments are placed. During the healing process the soft tissue or gums grow over the top of the implant. This tissue needs to be remove and a healing abutment placed. These healing abutments are in place for 10-14 days then the restorative dentist begins the impressions for the final crowns.
Above: This x-ray shows the final finished crowns in place with the dental implants. Not all dental implant cases require a sinus lift or bone grafting, however if your bone is inadequate not doing a bone graft and trying to “make it work” may lead to a failure and loss of the dental implant and associated crown.
Treatment Course #2
The patient above had lost the back or posterior molars years ago. Her options at this point are a partial denture or implant placement. Unlike the patient above, she had a few millimeters of bone existed between her mouth and the sinus allowing concurrent placement of dental implants and sinus graft.
Notice in this xray the bone placed around the end of the implants located in the patient’s sinus.
The placement of the healing abutments which allows the gum tissue to contour around the head of the implants. This allows the restorative dentist to make the teeth emerge from the gingiva mimicking a natural tooth.
This is the final xray showing the crowns in place and functioning.
Treatment Course #3
This patient is an example an upper full mouth reconstruction with individual implants and crowns. This patient is 87 at the time of treatment and presented with a failing upper crowns and bridges. She did not want a removable prothesis or denture, but preferred a fixed option. With her age, implants are still an option if treatment planned properly.
We removed her remaining upper teeth and simultaneously placed 7 varying length implants. The upper right molar was retained to help support her provisional denture. The denture was an interim prosthesis only while the implants were allowed to integrate.
This xray shows the placement of the healing abutments, the stage before the crown impressions.
 The patient above with a relax lip. |
 The patient above with a full smile. |
 The same patient close-up of the implant supported crowns. |
 The same patient close-up viewing the bridge from the right. |
Treatment Course #3
Congenital Missing Laterals, Before Implant Placement
After Implant Placement
Xray Showing Existing Bridges
Xray Showing Existing Bridges
After Restoring Implants
Poor Implant Placement:
(these cases were not performed by Dr. Johnson)
Case #1:
This patient has an implant placed 15 years ago and the placement was misaligned.
The implant is anlged posterior (towards the back of the mouth ) and buccal (towards the cheek).
This leads to poor oral hygiene; however, the implant is still stable and functional.
Notice that the retention screw is angled towards the cheek.
The screw should be aligned through the long axis of the tooth. In other words straight up and down.
History of Dental Implants
The radiograph above represents a subperiosteal implant. The type of implant rest on top of the bone and represented the height of implant technology in the 1970’s. Notice that the implant has separated from the mandible. This type of implant worked well for only a few patients. When the implants worked they lasted for decades, as in this case the patient functioned on the implant with a denture for 35 years.
This radiograph shows the history of dental implants. The implant on the right is a blade implant and represented the height of technology in the 1980’s. The implant on the left is the current design that resembles a natural tooth root.
