HOW ARE DENTURES MADE?

In the old days, dentures were carved out of blocks of hippopotamus tooth. Quite a hit and miss process it must have been. For the last hundred years it has been possible to mould dentures onto a plaster cast of the mouth. The process is called the lost wax technique and has been used for thousands of years to cast metal objects. You carve the shape you want in wax, and then cover it with plaster or cement. When the cement is hard you heat it up, the wax melts and is poured out through an access hole. You heat the metal until molten and them pour it into the mould. The teeth used to make modern dentures are made of acrylic. We make a plaster cast, set the teeth in wax and then replace the wax with acrylic using the lost wax technique.

HOW DO DENTURES WORK?

Dentures stay firmly on the gum in the same way that two glass sheets separated by a thin film of water stick together. It is vital that the two surfaces fit closely and that there is enough fluid to prevent air getting in. It helps if there is a large area of contact, as there is between the upper denture and the gum. If there is not enough fluid, because the mouth is dry, the dentures just don't stick on to the gum Denture fixatives help to provide a thick sticky fluid between the denture and the gum.

Dentures need to avoid being pushed away from the gum by the surrounding muscles. The tongue is a very active mover and so are the cheeks and lips.

The denture teeth need to come together evenly so as to avoid tipping and to make chewing efficient. Even so the force available for biting is much less than if the natural teeth were still there.

HOW DO IMPLANTS HELP?

Dentures can be stabilised by two or more implants placed into the underlying bone. When supported in this way dentures do not move about or get food under them and they don't press down and hurt the gum. Patients say that implants improve their quality of life. In North America and most European countries except the UK, implant supported dentures are considered the standard of care.

Implants have an additional longer term advantage in that they prevent bone loss which normally occurs when the teeth are extracted. This bone loss is more pronounced in the lower jaw which is why lower dentures usually have less bony ridge to keep them stable than the upper denture.

WHAT DO DENTURES DO BEST?

Dentures can look just as natural as your original teeth. In fact often they an be made to look better as we don't use any stained or misshapen teeth. Dentures do not always look natural as they may be produced on a production line and so lack individuality. If made with the participation of the patient and with the help of old photographs they can restore all the charm and appeal of natural teeth.

HOW LONG SHOULD DENTURES LAST?

There is no absolute lifespan for dentures. Some last up to thirty years. By this time they are quite badly worn but many patients remain happy with denture they have long been familiar with. The lower denture may be the first to get loose and require re-making or re-lining.

HOW WILL I KNOW WHEN TO HAVE A NEW SET?

If the dentures have become loose, food may start to accumulate underneath them as they move while eating. If the back teeth have become rounded and worn they will not chew very efficiently. The front teeth may become visibly worn and loose their good appearance.

If you find that using a denture lining you can buy over the counter helps to keep the lower denture stable it may be time for a new one.

NEW DENTURES; THE FIRST FEW DAYS.

What do I say to friends?

If you would prefer most people not to know that you have new dentures, and your new dentures do look slightly different, you may decide to divert attention from your teeth. If you are a lady then you might have your hair done the day you get your new teeth or alter the style of your makeup. If you cannot avoid a direct question then you could tell friends that you have had some new crowns.

How should I react to comments from close fiends and family?

Sometimes the remarks of our closest friends and family can at first be quite negative. They have not had the opportunity to get accustomed to any changes which have been incorporated into your new dentures. Whereas you have been part of this process of change over a few weeks. So they are a little unprepared and may just react against the apparently sudden change and say, "I think I preferred the old ones" As the days go by they will often change their minds and say they are actually beginning to like the new ones.

Sometimes the remarks of our nearest and dearest can be a little less innocent. Siblings are notorious for taking the opportunity to take the wind out of our sails. The art of deflating someone without sounding mean is a skill which can be acquired with long practice. Beware of remarks which start with that well worn cliche " to be absolutely honest". What follows is bound to be contrived.

"They are a little large/small aren't they"? may be said in with an air of concern and of course only with your best interests at heart. So, be on your guard. Don't expect delight. If it comes your way that is marvelous, but you may have to brace yourself for something less supportive.

How should I plan my first meal?

Start with food which is easily managed like fish pie, shepherd's pie or quiche. Rolls, pizza, bacon and steak may come later. Some foods like cheddar cheese can be surprisingly sticky. Many people prefer to have their first few meals in the privacy of their home, before eating in public. Use a little denture fixative until you become confident that the dentures are not going to move about while you are eating.

What should I do if the new denture hurts?

The dentist will spend some time at the fitting stage making sure that there are no painful spots. But there are some muscles around the denture which only contract strongly when you actually use them in chewing and swallowing. These may press against the denture border causing soreness after a meal. It may ease with time but the best solution is to trim the denture back at these points.

There are places on the gum where the skin in the mouth is very thin and the bone underneath quite sharp. These areas can also become painful and will need to be adjusted.

You may be able to carry on using the dentures before you can get back to your dentist, by taking them out as much as possible in between meals and certainly at night. Wearing the old dentures for a day or so also give the sore places a chance to recover.

THE FIRST FEW WEEKS OF YOUR NEW DENTURE

If I am still not happy with the appearance, what can be done?

Your dentist will have explained the importance of agreeing on any changes to the appearance while the denture teeth are still set in wax. If you were satisfied with the appearance of the teeth when they were in wax the dentist will assume that it is okay to proceed with the process. When the denture teeth are set in acrylic it is not easy to alter their position. It is not impossible though. It means cutting the teeth out, re-positioning them in wax and sending then to the laboratory to be re-set in acrylic. This process may be successful if just a few teeth are involved but there is of course the risk that the changes may still not look right to you. There is also the question of the additional cost of all this. If there are major problems with the appearance of you denture after it has been finished it may be better to start over from the beginning.

Your dentist may decide that he would rather return your fee and suggest that you try another dentist or may be prepared to make another denture.

What can be done if the denture is still painful after a few weeks and several adjustments.

One of the most common reasons for persistent pain from a denture is due to a habit of clenching the teeth together. New dentures may feel quite strange and perhaps due to some uncertainty about exactly what is in the mouth, denture wearers bring the teeth together and bite them gently into place. The force of the closure may be quite small but may be frequent. The accumulated effect of gently squeezing the gum causes slight swelling and bruising. The gum becomes tender and when under the much increased pressures of actually chewing it is very painful.

Most people who clench their teeth are unaware that they do this. It may be others who point it out The dentist will suspect that areas of pain which persist after adjusting the denture are due to clenching. It is also sometime possible to detect small shining facets on the denture teeth, which are a sure sign that the teeth are rubbing against each other without any food in between them.

There is not a great deal the dentist can do if pain is due to clenching, except give advice.

• This would be firstly to try and be aware of clenching and to make a conscious effort to keep the teeth apart when not actually eating.
• If this does not work then you may find it possible to take out the lower denture in between meals or at least when not in company. This is a rather radical step but it does insure that you cannot damage the gum by clenching the teeth.
• If the gum simply is not robust enough to take the pressure of dentures then implants may be a solution.

What can be done if the new dentures are loose

If the upper denture does not seat home with a slight squelch of squeezed out saliva, they may be an inadequate seal. The seal usually fails at the back of the denture so the dentist may check this using a softened wax compound to see if the seal can be improved.

If your mouth is dry, using an artificial saliva or sucking on a piece of ice may improve the seal. It is possible to have dentures made which have a reservoir of artificial saliva which is slowly released and this helps maintain a seal.

If the upper denture falls down when you laugh or open your mouth wide it may be that the flange which goes into the sulcus is too deep . The sulcus is where the skin of your mouth folds back on itself. The depth of this sulcus varies according to the muscle activity around the mouth. The dentist may be able to stop the denture from dislodging by shortening that part of the flange which is too long.

If the lower denture is loose it may be that there is a an area, often right in front where the flange is too long, causing the denture to lift up when the lip is active. Loose lower dentures are rather common due to the lack of ridge support and active tongue. Fixatives are sometimes helpful but many seem to wash out quite quickly. One of the strongest fixatives is called Secure and it is available only through the supplies, Dent-O-Care.

HOW SHOULD I CLEAN MY DENTURES?

There are a number of proprietary cleaners available but all require and suggest that you brush the fitting surface of the dentures. This is because the biofilm which sticks onto the surface is not easily removed by chemical cleaning. A denture brush and dishwashing liquid will do all that is necessary. If you tend to accumulate calculus, a whitish hard deposit particularly around the lower front teeth you may need to ask an oral hygienist to remove it for you.