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Case Examples
—What type of Implant Restorations are there?
This page is designed to show you several examples on how a tooth or multiple teeth can be restored with the help of dental implants. The individual examples will be underlined with Before and After pictures. To start off, we need to classify the different prostheses available. This way you have a better understanding of what your doctor presents to you when he or she discusses the case with you.
There are three main categories that need to be distinguished for our purposes:
- Fixed Prostheses
- Removable Prostheses
- Fixed-Removable Prostheses
Fixed Prostheses are, as the name implies, fixed to the dental implant and the patient cannot remove them (although the doctor usually can). Within this category fall single-tooth as well as multiple-tooth replacements. Fixed Prostheses are usually the most desirable prostheses in implant reconstruction, however depending on the individual situation that may not always be indicated. Multiple teeth in a row are usually splinted together in a Bridge, which is then attached to the implants. Below you see several examples of Fixed Prostheses.
The first set of images represents a Single-Tooth prosthesis replacing a first molar in the patient’s upper left jaw.
To the left you can see the original condition from a frontal view. Notice the deep overbite (the lower incisors are barely visible). This patient also underwent Orthodontic treatment in addition to Implant Reconstruction (notice the difference on the right image). The implant was in fact, utilized as a solid anchor for the braces, since integrated implants do not move under orthodontic force (studies have shown that they can easily withstand orthodontic forces of 1000 grams or more and maintain their stability).
The left picture shows the original condition with the first molar missing on the patient’s left side. On the right you can see the space filled with an implant supported single crown.
To the left you can see a side view of the missing first molar and to the right the result after implant reconstruction (arrow). Notice how natural the gum (gingival) architecture around the implant crown follows that of the adjacent natural teeth. The implant will maintain these nice contours, because it will prevent future bone resorption.
The next three images show a fixed prosthesis replacing three teeth on the patient’s lower right side and one tooth on the patient’s lower left side.
This image to the left shows the original condition of the patient. The patient was treatment planned for a three-unit implant supported fixed bridge on his lower right jaw and a single implant supported crown on his lower left (arrows).
This image shows the finished implant supported bridge on a stone cast of the patient’s lower jaw, ready to be delivered. As of today it is largely recommended to splint the individual implant crowns together into a bridge, in order to achieve better biomechanical loading characteristics of the implant fixtures. As you can see, there is no floss contact between the individual teeth (arrows).
Here you can see a clinical image of the three-unit Implant Bridge and the single implant crown in place (arrows). The above examples illustrate what Fixed Prostheses supported by dental implants may look like. Please note that these are only two examples. There are many more different ways to construct a fixed prosthesis for implants, however, the general concept remains the same. More examples of Fixed Prosthesis can be found in the section How Implants are Placed and Restored and in the Bone Grafting section under Miscellaneous Grafting.
Removable Prostheses are attached to implants in a way that permits the patient to remove them at any time. This usually also implies that the prosthesis is not completely supported by dental implants, but rather by the implants and the tissues in your mouth. In fact they are usually your typical Full Denture or Partial Denture that derive some extra retention out of the implants. As mentioned above, one usually tries to strive for a Fixed Restoration, however in certain situations compromises have to be made and this type of restoration can still benefit the patient tremendously. Below you can see again several examples of Removable Prostheses for implants.
To the left you can see a clinical picture of a toothless lower jaw. Many patients are all too familiar with this type of situation. The traditional method of replacing teeth in this scenario was to make a full denture, which usually never quite satisfies a patient who is used to having teeth. On a ridge like the one on the right, a patient would have a lot of trouble with actually retaining the denture, let alone chew with it at a satisfactorily level.
If the patient’s desire is to get only more retention out of a removable denture, as little as two implants can be enough to achieve that. The picture on the left shows the inside of a conventional denture modified with O-ring attachments (arrow) that clip to special implant abutments. The picture on the right shows the same type of denture, however the inside here is modified with a clip to attach to a bar.
Regardless of the attachments processed into the underside (tissue side) of the denture, the topside may look the same for either of the situations and usually does not differ much from a conventional denture. To the left you can see an image of an implant denture. These dentures are sometimes also referred to as Overdentures. They are still removable, however they ‘snap’ onto the implants or their abutments.
Above to the left you see two implants with ball–type abutments in the lower jaw to fit the denture with O-rings, illustrated above. The right image shows a patient's lower jaw with a Subperiosteal Implant in place. The bar you see fits to the clip-type denture above. The Subperiosteal Implant has the advantage of stabilizing the denture to a much higher degree than the two implants on the left due to the full arch bar, however the prosthesis is still considered a denture or overdenture.
No matter which implant modality or attachment system one chooses, the denture may still look like a conventional denture in the mouth, however it has more retention than one without implants. The patient can still remove it though. If an edentulous patient wants more retention, chewing force and a more fixated prosthesis, a Fixed Removable Prosthesis as described below would be the better way to go.
Fixed-Removable Prostheses are usually found in full mouth reconstruction for patients who have either one or both jaws without teeth. This prosthesis is usually completely supported by implants (with no or little tissue contact—just like a Fixed Prosthesis), however the patient or the doctor can remove part of the prosthesis for hygiene access. This entire set-up usually consists of two parts: a retentive metal part (usually some type of bar attached to the implants) which is not removable and the actual super structure which has the teeth on it, which is removable. This super structure fits over the metal part (connected to the implants) and it usually stays connected to that metal part via friction mechanisms and/or retentive clips. The images below will illustrate this somewhat better.
Let’s start out with the same situation as above: a lower jaw without any teeth, but this time the patients wants a more fixed restoration that does not move around and gives him or her more chewing power.
One parameter we need to upgrade, in order to achieve this goal is the number of implants. Five to six implant fixtures is a minimum for fixed-removable appliances in the toothless lower jaw and at least eight implants for the toothless upper jaw. One way to achieve this is shown on the top two images. Six implants connected to a precision milled bar, which will friction-retain the prosthesis as shown farther below. The right image shows five implants placed with abutments on them. Here we will connect the prosthesis directly to the implants with screws. Both set-ups offer a similar degree of stability, however the top method still permits the patient to remove the prosthesis for hygiene access, whereas in the right setup, only your doctor can remove the screws to retrieve the prosthesis, as is illustrated at the right.
The top two images show the matching prosthesis for the milled bar setup shown above. The underside shows the metal structure, which is cast to fit the milled bar. You can also see two little swivel locks (arrows) which lock the prosthesis into the bar when they are closed. The top right view shows the action of the swivel locks in their open position. This permits the patient to remove the prosthesis. The right image shows the other type of prosthesis, fixed to the implants with screws (arrows). As you can see there is no option for the patient to retrieve this prosthesis.
This set of images shows these two types of prostheses in the mouth. The image on the right shows the esthetic shortcoming of the screw-retained prosthesis. Since the patient cannot remove this prosthesis him or herself, hygiene access needs to be provided for the patient to be able to clean the implants. The images on the top left show that the friction-retained prosthesis features better esthetics due to its inherent retrievability. The patient can simply remove the prosthesis and clean the implant/milled bar setup. To reiterate, if supported by the same number of implants, both prostheses offer the same amount of support and chewing efficiency, however one can be removed by the patient, the other can not.
The above examples are mere representations of the three different categories. There are several ways to construct these prostheses with some alterations to the ones shown above, however, the concept still remains the same. We mainly presented the lower jaw for the Fixed-Removable Prostheses, because this is the most frustrating conventional denture for most patients to deal with. Similar appliances can be made for the upper jaw except for the screw-retained example above as it was shown. An appliance like this (no tissue contact) would translate into severe phonetic problems. If the upper jaw is and has been without teeth for a long time and a moderate amount of tissue and bone resorption has taken place, the milled bar appliance offers more advantages, due to their inherent retrievability. The other factor is that the upper jaw has to be over-engineered with respect to the number of implants placed, due to the fact that the bone is not as dense in the upper jaw as compared to the lower jaw. Eight to ten implants are considered adequate for a Fixed-Removable Prosthesis in the upper jaw.
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