Dentures

An overdenture is a denture that fits over the top of another structure. This may be over the top of some remaining natural teeth, over the top of remaining tooth roots, or attached to dental implants. The remaining teeth, roots or dental implants act as anchors to secure the denture in place. This method is sometimes used in the lower jaw where problems with stability and securing a denture are more common.

Implant-supported dentures

Dentures can be attached to dental implants to improve stability. Dental implants are a special type of titanium post that is surgically inserted into the jawbone. The implants then attach to and anchor the denture in place.

The denture can be screwed onto the implants securely by the dentist. This type of denture is held in place permanently. A dentist can remove this type of denture by unscrewing it for regular cleaning and maintenance.

Many people who have had trouble with loose, uncomfortable dentures choose to have an implant-supported denture made. These will not move when speaking or eating and do not rub painfully against the underlying gum. They also allow the wearer to eat foods that are hard and chewy, something that is not possible with regular full dentures.

 

There are four different types of implant-supported dentures for replacing a full arch of teeth.

Bar-retained dentures

Two or more dental implants are placed into the jawbone at intervals and a metal bar is attached between them. An acrylic (plastic) denture is then made to clip securely into place over the bar. The denture will usually have a small space between its base and the gums, which needs to be kept clean. The denture is taken out at night for cleaning and to allow proper cleaning of the implants and surrounding gums. This type of implant denture is suitable for either the upper or lower jaw. In the upper jaw, it does not need to cover the whole roof of the mouth, as a regular denture would, so it allows the wearer to have more natural taste and texture sensations with food. The denture is also less bulky.

Ball-retained dentures

Several implants are placed in the jaw and each one holds a ball attachment. An acrylic (plastic) denture is then made with matching sockets to clip securely in place over the implants. The denture will usually have a small space between its base and the gums, which needs to be kept clean. The denture is taken out at night to be cleaned and allow proper cleaning of the implants and surrounding gums. In the upper jaw, the denture does not need to cover the whole roof of the mouth, as a regular denture would.

Full arch implant-supported bridge

Some people prefer to have an implant-supported denture that they do not have to remove at all. This is called an implant-supported full bridge. It is fixed in place onto a number of implants, held securely by screws that only the dentist can remove. It is made of acrylic or porcelain and fits closely to the gums. Special floss and brushes are used at home to clean around the implants. These full-arch bridges tend to be more expensive than implant-supported dentures, as they usually require more implants and cost more to make.

'All-on-four' is a newer technique where only four implants are placed into the jawbone and a bridge is secured in place over these. The implants are placed at angles in the bone, to maximize the use of sturdy bone. This 'all-on four' method is usually less costly than placing more implants to support the denture. Your dentist can discuss what will be the best option for you.

Mini-implant supported dentures

Mini-implants are similar to regular dental implants, except that they are much thinner and smaller, and solid on the inside, while regular implants are hollow. They are much simpler to place into the jaw, as they do not require a complex surgical procedure and the healing is much faster. They are favored by people because the surgical placement does not involve gum surgery or removal of bone before placement. As a result, people experience less swelling and discomfort after the placement procedure. In most cases, mini-implants can be attached to a denture immediately, avoiding many months of waiting for the implant to heal and integrate into the bone. For these reasons they have become very popular and have comparable success, so far, to conventional implant-supported dentures.

Mini-implants cost much less than regular implants. They are popular for supporting dentures, where four or more mini-implants can be placed to attach to a denture base securely. Some dentists, however, may be reluctant to recommend them as they are a relatively new technique. There is not much scientific data to prove their success, although results to date show good success rates if used in areas of minimal biting forces. Mini-implants are not as strong as regular implants and so should only be used in areas of light chewing, such as the front of the mouth, or for supporting dentures.

Partial dentures

A partial denture is made to replace one or more missing teeth and relies on the remaining natural teeth to hold it in place. A partial denture consists of an acrylic or metal base with acrylic teeth fixed in place. Metal clasps within the partial denture fit securely around existing teeth. A certain number of healthy and well-positioned natural teeth are needed to secure the partial denture. The partial denture is usually removed nightly for cleaning and to clean the remaining natural teeth and gums.

Acrylic partial dentures

An acrylic partial denture is made entirely of acrylic (plastic) and uses metal wire clasps to attach to the remaining natural teeth.

The benefits of an acrylic partial denture are:

• Relatively lower cost to make;
• Teeth and clasps can be added to it if more natural teeth are lost after the partial denture has been made;
• It can be repaired easily, and;
• It can be re-lined easily when the shape of the underlying gums change over time.

The disadvantages are:

• The acrylic can be prone to breaking and is not as strong as a metal partial denture;
• The acrylic base is somewhat bulky in the mouth and can be difficult to get used to;
• The acrylic base of an upper partial denture often needs to cover the whole of the roof of the mouth for strength. Many people find this bulk of plastic difficult to get used to, and;
• The clasps are not as strong or sturdy as those in a metal partial denture and can be prone to breaking, or may need to be frequently tightened.

Metal (cobalt-chrome) partial dentures

Partial dentures can also be made of a thin base of metal with acrylic teeth and gums attached to the base plate. These are called cobalt-chrome partial dentures.

The advantages of cobalt-chrome partial dentures are:

• They are sturdier and stronger than acrylic partial dentures;
• They are less likely to break and can withstand heavy chewing forces;
• They are less bulky than acrylic dentures and fit more closely to the remaining teeth and gums;
• They are less prone to collecting plaque due to their highly polished surface and so are better for oral hygiene;
• The clasps are stronger and less likely to break or loosen over time;
• In the upper jaw, there is no need to cover the whole roof of the mouth as with an acrylic denture. This often makes for a more comfortable and less bulky fit, and;
• The acrylic teeth on the cobalt-chrome base can be replaced if they wear down over time, without having to remake the whole partial denture.

The disadvantages of a cobalt-chrome partial denture are:

• They are more expensive than acrylic dentures, and;
• It is difficult to re-line or remodel if new teeth need to be added, or if the underlying gums change shape.

Making and fitting new dentures

In order to make a denture, your dentist will first examine your mouth and jaws and ask you some questions about your health and previous dental experiences. It is important to take the time to thoroughly discuss any issues, so you can make an informed decision about your treatment.

When a decision has been made to make a denture, the dentist will take an impression of your mouth and any existing teeth that remain, using a special putty-like impression material.

The shape and color of the new denture will be decided by you and your dentist.

The impressions and instructions are sent to a dental laboratory where the denture or partial denture is made. There are usually a few appointments required to 'try-in' the denture in the various stages of manufacture before the final denture is completed.

Learning to live with dentures

People often take some time to become accustomed to their new dentures. Typically the new denture will feel strange to begin with. It may feel tight, uncomfortable and bulky in the mouth. You may notice an increase in salivation when wearing the denture. Your speech may also initially be affected by the denture, although this generally improves with time.

Give yourself time to adjust to the denture. Eating soft foods and removing the denture for short periods of time to rest your mouth is advisable. If you are tired or unwell, a new denture is likely to feel even more uncomfortable. You should make an appointment to visit your dentist to check your new denture a few weeks after it has been made. New dentures often require a few adjustments.

If you have been fitted with an immediate denture (inserted in the same appointment as your teeth are removed), your dentist will need to check your denture more often to ensure there is proper healing of the gums. You will be given special instructions for what to do after the extractions.

Denture adjustments

Just as a new denture requires adjustments to make it more comfortable, older dentures will also need alterations as the mouth changes.

Once teeth have been removed, a slow process of bone resorption occurs in the mouth. This means that some bone slowly disappears and the gums will appear to be shrinking back. When this happens, a denture will become unstable. You may notice that your denture does not fit as well as it used to. It may move around and rub on the gums, causing ulcers and sore spots. The denture may slip out of place when eating or speaking. See your dentist to make any adjustments to your denture. Your dentist may be able to re-line your denture by taking a new mold of your mouth and adding some acrylic to the base of the denture. A soft lining may also be recommended to cushion the fitting surface of your denture. There are also many removable lining materials available that can help your denture adhere to your mouth and prevent slipping. These can be bought over the counter and are easy to apply at home.

Cleaning your dentures

Dentures should be removed from the mouth and cleaned after every meal or at least twice a day after meals. A regular toothbrush and denture-cleaning cream or mild soap can be used to clean the denture. Avoid regular toothpastes, as some are abrasive and can scratch the surface of your dentures. Ensure you brush both the outside and the inside fitting surface of the denture. Special denture cleaning brushes are available.

It is best to clean the denture while holding it over a basin of water or over a towel so that it will not break if accidentally dropped. If you have a partial denture, you should also thoroughly brush and floss your remaining natural teeth at the same time. A partial denture sits in contact with natural teeth and gums, and can trap food around them. This will put your natural teeth at a greater risk of dental decay and gum disease. Brushing all the surfaces of the teeth and dentures is important to avoid further damage and loss of more natural teeth.

Do not use methylated spirits or other harsh chemicals to clean your denture. Also, avoid washing them in boiling water, as they may melt or warp from the heat. Special denture cleaners are available and can be used to soak the denture overnight if needed.

Possible problems with dentures

Any kind of new denture is likely to feel uncomfortable and foreign at first. A settling-in period of at least a few weeks is to be expected.

Initial problems with a new denture include:

• Excess flow of saliva in the mouth. This is usually temporary, although can be very uncomfortable for a few days to weeks;
• A change of speech. It often takes some time to learn how to speak with a denture in place. Some minor changes in speech can be permanent when wearing dentures;
• Keeping the denture in place. Learning how to do this can take some time, as the muscles of the mouth learn to move differently to hold the denture in. People with a dry mouth and low saliva flow can also experience difficulty keeping dentures in place;
• Sore spots. These are common with new dentures. Try to wear them as much as possible. If you need to have the denture adjusted because of a sore spot in the mouth, be sure to wear it before your appointment so the dentist can see exactly where the problem is, and;
• Adjustments to improve the fit. New dentures often require the dentist to adjust the fit and relieve any areas that irritate the gums. You should avoid making your own adjustments to a denture.

Long-term problems with dentures include:

• Fungal infections of the mouth. If dentures are not removed and cleaned daily, a fungal infection, such as candidiasis, can develop. This results in a reddened and painful palate and gums, and requires medication to resolve;
• Changes to the shape of the underlying gums over time can result in ill-fitting, uncomfortable dentures. It is often necessary to re-line or remake dentures every 3-7 years to maintain proper fit and shape;
• The face and jaws can change shape over time after natural teeth are removed. This occurs because the jawbone resorbs or shrinks back once the teeth are gone and continues to do so for many years. There can be significant extra costs if dentures need to be remade or re-lined frequently;
• Removal of all the natural teeth and replacement with dentures often requires permanent changes to a person's diet. Unless your denture is secured with dental implants, it may not be possible for you to eat very sticky, chewy or hard foods without dislodging your dentures. Chewing gum, hard nuts, toffee and tough meat are usually avoided by people who wear dentures. Taste can also be altered because of the large amount of plastic covering the palate in upper denture wearers, and;
• Lower dentures are usually more difficult to keep in place than upper dentures. Many people have ongoing problems with loose and uncomfortable lower dentures.

Dental visits

Before making any decisions about dental treatment, it is important to discuss your treatment with your dentist. Be sure to tell your dentist about any medical conditions you may have and medications you take. This can be very important in deciding which treatments are suitable for you.