Dental Implants

Overview

Dentistry has undergone many changes during the past quarter century. The most significant changes have been in the field of implant dentistry. This treatment has dramatically increased the treatment possibilities for patients; often allowing us to provide treatment results that are significantly improved over older traditional treatment options from a functional or chewing perspective or from an esthetic aspect. Implants also have positive effects on bone and help preserve jaw structure after tooth loss. Implants are highly successful based on a review of the literature, but they are not immune to failure, despite adequate planning, surgical technique and appropriate restoration. Long-term success rates reported in the dental literature generally vary in the range of 90% to 98% depending on the study.

Certain terminology used in discussing dental implants needs to be reviewed:

Implant: in our context, this refers to the surgically placed component or screw that sits in the jaw structure. It is also referred to as a fixture.

Prosthesis: refers to the components that attach to the implant. In the case of the replacement of a tooth or several teeth, this includes several components: The crown (tooth) and an intermediate screw retained attachment or abutment.

Integration: refers to the �fusing� of the bone to the implant.

The tooth or crown is either cemented onto the abutment or screwed into the abutment. When the latter is done, an access hole through the top of the crown is sealed with an imperceptible filling material.

There are many types of implants. Regardless of their design or manufacturer, implants basically act as new roots or anchors upon which new teeth are constructed. Implants are generally made of titanium or titanium alloyed to aluminum and vanadium. Titanium or alloyed titanium implants form a titanium oxide layer when implanted, rendering them biocompatible, i.e. no known foreign body reaction or rejection risk.

Once implants are placed in the jaw, they are allowed to heal for varying lengths of time; this is referred to as the Osseointegration period, during which bone will bind to the implant surface. Once the implant has integrated into the bone, some form of restoration is built onto it. Although it is common to allow implants to heal or integrate before restoration, in some cases, teeth may be built on the implant at the time of placement. If this is appropriate, the dentist will discuss this with you. Implants can be used to support single teeth, multiple teeth or bridges. They may also support removable dentures. It is not common to connect natural teeth and implants. There is quite a bit of controversy on this subject, and many clinicians suggest that there are more complications when teeth and implants are connected. However, a review of the dental literature indicates that there are no more failures or complications than traditional techniques.

Contraindications to Implant Treatment

The ideal implant candidate is in good physical health. Poorly managed health problems such as diabetes, renal disease, uncontrolled hypertension, liver disease, leukemia, severe valvular heart disease, blood clotting disorders, hepatitis (debilitating or transmissible), collagen or bone diseases and immucocompromised states can negatively impact the results of treatment and are considered contraindications to treatment. Implant placement should not be considered during pregnancy. Osteoporosis or osteopenia have not been shown to increase the risk of implant failure.

Smoking is considered to be a major risk factor contributing to implant failure. In our practice, we generally do not place implants in patients who smoke more than a few cigarettes per day. Grinding (bruxism) is also considered detrimental to the long-term success of implants and must be managed with a nightguard and/or other therapy. Other contraindicaticms include other habits such as nail biting, pencil biting, poor oral hygiene, heavy alcohol consumption. In some cases, dental implants may be contraindicated where jaw dimensions are insufficient over nerves or under the sinus or nose to accommodate proper implant placement. In many cases, the deficient bone can be regenerated with bone grafting procedures.

Your physician may be consulted in cases where extra precautions are necessary: this includes patients with histories of blood dyscrasias, pulmonary problems, psychiatric or psychological disorders, mental retardation, chemotherapy, radiation therapy to the site of implant placement, hemophilia. Thorough medical work-ups may be recommended in cases of: cardiovascular problems, congestive heart failure, coronary artery disease, prosthetic heart valves, endocrine disorders, Parkinson's, bone disorders including osteoporosis and bone pathology or malignancies.

How Dental Implants are Placed and Restored

In the majority of cases, placing implants is a fairly easy surgery for a skilled surgeon. These are procedures that are done under local anaesthetic (freezing). At times a mild oral sedative may be prescribed if the patient is very anxious. If you have severe anxiety or are a dental phobic, you may be referred to an oral surgeon who could place you under general anaesthesia. Our experience is that most patients do very well through this type of treatment. Patient's often comment that the experience was much easier to tolerate that they expected, and similar to having a filling or crown preparation.

The following simple case illustrates the implant surgery. 'A small incision is made in the site where implant placement is planned, and the tissue is opened to expose a small amount of the bone crest. The site to receive the implant is marked using a surgical guide or plastic reproduction representing the ideal tooth position. The procedure involves preparing a receptor site or socket; this is accomplished by drilling a hole in the bone, and gradually deepening it and widening it to ideal dimensions. The implant is then screwed into position. In the past, implants were routinely submerged under the gum to allow healing in a protected environment (two-stage protocol). In the vast majority of cases today, implants are placed in a non-submerged environment. In order to accomplish this, a component called a healing abutment is seated on the implant, extending the implant at least 3mm. The gum is then stitched around the healing abutment, so that about 1-2mm of the metal cap protrudes above the gum. This is called a one-staged protocol. If you wear a removable appliance to replace the missing tooth/teeth, it will be adjusted to allow you to continue to wear it. At times, other types of transitional tooth replacement options are recommended and provided. In appropriate cases where implant stability is adequate, temporary teeth may be built directly to the implant(s); this is referred to as immediate loading. In cases involving more extensive treatment, it may be necessary to avoid wearing removable dentures for the first few weeks following the surgery. Post-surgical instructions will be reviewed with you, verbally and in writing. Antibiotics are routinely prescribed, since this lowers the risk of infection and enhances success rates.

Typical Implant Surgical Treatment

Interestingly, most patients have little to no post-surgical pain. This probably relates to the fact that the bone that is prepared to take the implant has no nerve endings. Any pain is probably the result of the small incision made in the gum. Generally, Aspirin-like drugs like Advil, Motrin or generic Ibuprofen control any discomfort very easily. For patients with an Aspirin intolerance, Tylenol is usually prescribed.

Post-surgical swelling and bruising may occur. These side-effects are more common in more complex cases. Applying ice packs/frozen peas intermittently during the 48 hours after surgery can help minimize swelling and bruising.

Typically, a minimum of 2 post-surgical follow-ups are scheduled during the months following surgery. These appointments are brief, but they are necessary to ensure that the implant(s) is/are healing normally. At the final check, an x-ray is taken to assess the bone level and density. The total healing time varies from 3 to 4 months in the case of implants placed in the lower jaw, and 5-6 months in the case of implants in the upper jaw. There are cases where healing may be shorter or longer. The implants can then be restored.

Potential Risks/Complications Associated with Implant Placement

As with any type of surgical procedure, there are potential risks associated with implants at any step of the entire implant reconstruction sequence. Complications can range from immediate post-surgical problems to ones that surface many years after the implants have been in function. Often, corrective measures can be considered if the problem is diagnosed early. In order to avoid complications once the implant is in function, proper maintenance and care by the patient are very important.

In the lower jaw, the major risk that will be evaluated and discussed is potential injury to the major nerve called the inferior alveolar nerve below your back teeth during the surgery. Damage to this nerve could result in permanent numbness in that area of the mouth, resulting in a sensation similar to being frozen. This risk is very low and it should not occur when cases are properly planned. Although uncommon, partial numbness to small areas on the lower lip and chin area can occur due to temporary fluid pressure on the nerve. This is usually short lived or of moderately short duration when it occurs.

Your case will also be assessed to determine whether the position of teeth adjacent to the potential implant site are potentially at risk to be damaged during drilling. This can be a risk in cases where adjacent teeth are poorly positioned due to tipping or migration. If relevant, you would be advised of this risk factor.

The risk of infection after implant placement is low, but certainly possible. It is unusual for this to occur.

Infection can result in loss or removal of the implant. It is often unclear as to what has caused an implant to become infected and fail; it may be the result of contamination by bacteria present in the surgical site.

Certain activities such as smoking, wearing a denture or partial denture that applies too much pressure are also potential factors contributing to failure. Last, poor surgical technique resulting in overheating of the bone during the receptor site preparation is sometimes implicated in early failure.

Post-restoration complications include problems or complications affecting either the implant(s) or the prosthesis constructed on the implant(s). Once the implant is properly restored, things can go wrong at times. Severe bone loss can develop in some cases over time. This may be the result of excessive load on the implant. Chewing or grinding heavily on the implant tooth has been implicated in heightened risk for failure. Extensive bone loss can increase the risk that the implant or some of the retaining components including the prosthesis may fracture.

Other problems are usually associated with the prosthesis built on top of the implants. This may include screw loosening or porcelain/acrylic fracture. These types of problems are usually reparable.

Maintenance and Care

This is an important aspect of maintaining implant health. Oral hygiene procedures including brushing and flossing should be carried out on a daily basis. Other specialized instruments may be recommended, depending on the type of prosthesis constructed. Examinations and periodic x-rays are essential: Appropriate intervals will be discussed with you.

Implant Placement to Replace Single Teeth

A single tooth can generally be replaced by one of three methods: a removable denture (sometimes referred to as a flipper), a non-removable or permanent bridge that uses adjacent teeth to support a missing tooth and an implant supported tooth. A flipper or partial denture is generally considered to be a temporary form of tooth replacement. It rarely is considered as an appropriate long-term form of restoration to replace a single tooth. A bridge is a non-removable tooth replacement alternative that can provide excellent results from functional and cosmetic aspects, but at some biologic cost. A bridge is retained by preparation or cutting adjacent teeth into a post-like structure, and cementation of 3 or more fused crowns. The advantages of implant supported crowns over bridges include:

It is not necessary to prepare or drill the adjacent teeth;
Individual teeth are created in contrast to fusion of teeth. This makes it easier to clean;
Implants are not at decay risk or risk of root canal problems like teeth are. These types of problems are linked to bridge failure.

When a person is missing one tooth there are two options for replacement, a single dental implant or a bridge.

Implant Placement to Replace Multiple Teeth

Implants may be recommended to replace several adjacent missing teeth, by building individual teeth on implants or by building bridges supported by multiple implants. Alternatives to implants that will be discussed with you include removable dentures or in some situations, long-span non-removable bridges. In some cases, implants may be the only non-removable alternative available. For instance, the loss of the back chewing teeth or molars, cannot be replaced by bridges which need front and back teeth for anchorage.

Implant Placement to Support Removable Dentures

Dentures are devices using to replace all teeth. A partial denture replaces several missing teeth and uses remaining teeth for anchorage by hooks or attachments. Both types of appliances are removable. Some patients adapt very well to these types of dental appliances, but others experience significant problems because of looseness or poor retention. This is a common problem in the case of complete lower dentures or partial dentures that are supported by weak or compromised teeth.

Implants provide a solution for many patients who have problems with denture looseness or movement. Implants can be used to secure a denture and therefore improve diet, speech, confidence and comfort.

Varying numbers of implants may be recommended to help support a denture. The minimum number of implants is two, generally placed where the cuspids (eye teeth) used to be. A denture will be retained by ball/socket attachments in these cases. If more that 2 implants are placed, the denture retention and stability increases. If 3-5 implants can be placed, generally a bar is built onto the implants and a denture with clips snaps onto the bar.

Dental Implant FAQs

How successful are dental implants?
There are many factors that can affect the success of implants. Health is an important factor. Patients with health problems like poorly managed diabetes or heavy smokers tend to have more healing problems leading to adverse treatment outcomes. Patient selection is important, proper diagnosis and treatment planning set the foundation for success, good surgical technique and proper restoration are essential. Under favourable conditions, success rates vary form 90% to 98% based on most published academic studies.

Why should I consider an implant instead of a bridge to replace a missing tooth?
Although a bridge may be less expensive than an implant and it is generally faster to have a bridge done, in many situations an implant supported tooth is considered to be the ideal treatment option. Important issues in the decision to have an implant placed instead of a bridge include: an implant is the closest treatment alternative to a natural tooth, teeth adjacent to a missing tooth remain untouched and are not needed for anchorage (this is ideal when adjacent teeth have no or small fillings), the implant helps to preserve the bone and gum structure, it is easier to clean around a single implant compared to a bridge, there may be long-term negative side-effects on the health of teeth that are prepared to support a bridge (recurrent cavities, root canal problems, bridge failure).

Is age an important factor in implant treatment?
Increasing age is not considered a deterrent to implant treatment. Overall health is more important than age. In fact, an 80 year old person may be in much better health than a person who is many years younger but who has health complications. As long as a person is in good health, perceives the treatment as beneficial to their function and looks and has the necessary financial resources, this type of treatment should be considered when the treatment options are presented.

How many implants do I need?
This question is difficult to answer without assessing each individual's case. It is ideal to consider the replacement of each tooth with an implant, but this may not be necessary depending on the proposed method of restoration recommended by your dentist. Each case is independently reviewed: optimal numbers of implants and locations will be discussed with you.

Is it painful to have implants placed?
With adequate local anaesthetic (freezing), there should be not pain during surgery. You will feel sensations like touch and pressure during the treatment, but no pain. For the average patient, there is little to no post-surgical pain associated with this type of treatment. The typical patient is able to manage any post-surgical pain very effectively with over-the-counter drugs. There are certainly some exceptions to this rule; it is possible to experience discomfort that is more intense than average and longer in duration.

Can I afford implants and will my insurance pay for this treatment?
Implant based treatment plans can be costly. Costs vary significantly with the complexity of the treatment, the number of implants being placed and the type of prosthesis being built on the implants. Each case needs to be assessed independently. Insurance plans may offset some of the fees that you will incur, but compensation can be very poor with some plans. It is necessary to bear in mind that insurance plans rarely pay for the best treatment possible; they are designed to defray costs associated with acceptable methods of restoration at costs that fall within their budgets. Remember that insurance carriers must be profitable: This is rarely accomplished by paying for state-of-the-art treatment proposals.