A denture is a prosthesis or full set of top or bottom teeth held in place by implants to keep it steady and prevent it from tilting.
Full traditional dentures
Full traditional dentures in the elderly or not-so-elderly are held in place by their gums and by the underlying bone in the upper or lower jaw.
With time, the gum and the bone are reabsorbed, causing them to lose height and depth. This means that the dentures no longer fit properly and start to move, particularly when speaking or eating.
When this happens, the dentures are filed down or filled with the same pink resin used to make them, adapting them to the new gum shape. This process can be repeated several times, although new dentures will probably be required at some stage.
Some people have absolutely no problem adapting to dentures, but others have trouble with them either from the beginning or after a few years, even if they use adhesive cream. These denture adhesives tend to work very well and will keep dentures correctly in place while speaking and eating.
Given that they have a cushioning effect, they prevent the denture from causing pain and rubbing against the gums, particularly in the case of patients who suffer from a dry mouth.
Options available to the patient
Patients who simply cannot get used to dentures have two options:
- To have a completely fixed denture fitted, normally in porcelain, held in place with some eight implants. However, this requires your mouth to be healthy and have enough bone; it also requires you to be able to afford having this kind of important work done on your mouth.
- The other option is to have removable dentures fitted which require a minimum of two implants to hold them in place in the case of the bottom set, and a minimum of four for the upper set.
Advantages of overlay dentures compared to traditional complete removable dentures
The traditional full removable or mucosa membrane-supported denture leans against the soft tissue, i.e. the gums and underlying bone, while your cheeks hold your denture in place while speaking or chewing.
The top denture often sits snugly in place due to the fact that the palate provides a suction movement which holds it tightly against the roof of your mouth.
However, on the lower part of the mouth, your tongue will push the denture forward. This means that the full set of bottom dentures may be difficult to keep in place. In fact, implants were precisely created to hold complete bottom dentures in place. While the overlay denture also comes as a full set, it is held in place with two implants for the bottom set and four for the top set.
This difference lies in the fact that the bone in the upper jaw is spongier and weaker than that of the lower jaw, meaning that more implants are required to hold the denture in place. The overlay denture is held in place by the implants in the top of your mouth, leaving the rear part of the denture to rest on your gums, resulting in great stability.
System to hold the overlay denture in place
Having had the implants fitted, we must wait for three or four months until the bone strongly fuses to the implants which, as you will know, are made from titanium screws.
During this time, you will wear a provisional denture adapted to the gum and bone round the implants, while the bone implants heal and the osseointegration follows its course.
After this time, we will make the permanent denture for connection to the implants by means of ball attachments known as Dalbo or Locator systems. These systems have a ball or male mechanism fitted to the implant, and a corresponding female socket fitted to the denture. The denture mechanism therefore slots into the underlying implants.
Another typical fastening mechanism consists of a custom-made metal bar to join the implants. Here the denture sits on the said bar, held in place with hooks fitting perfectly into the bar. The overlay denture can be easily released from its fastenings for cleaning after every meal.
Difference between an overlay denture and a fixed denture on implants
Implants, or rather the place where the implants protrude through your gum and into your mouth, must be cleaned and brushed with great care. Just like your own teeth, poor hygiene can lead to periodontal disease or pyorrhoea, since the bacteria produced by food remaining in the area around implants may irritate your gums and cause peri implantitis or inflammation of the gum and tooth around the implant.
If left to progress unattended, this situation will lead to bone loss, and may even with time cause the implant to fall out.
To brush your teeth properly, if you have a fixed denture on implants, you must be very careful, disciplined and rather good with your hands. The overlay denture, on the other hand, given that it can be removed, is much easier to clean, meaning that your implants can also be easily cleaned. The overlay denture is therefore more advisable than a fixed denture in the case of elderly people who need or may need help to clean them in the future.
In principle, the fixed denture is the most aesthetic option due to the fact that it is normally made in ceramic, although today resin dentures too are highly aesthetic.
Furthermore, in the case of fixed dentures, the teeth start at your natural gums.
The problem occurs when you have lost all of your top teeth and bone, meaning that the gum beneath your upper lip also loses height and width. The bone therefore moves upwards, meaning that the ceramic teeth will be longer than your natural teeth. This will only be noticeable if you have a very high smile line, i.e. if you show great expanses of teeth on smiling.
The bone beneath your top lip may also recede and sink, thereby accentuating the vertical wrinkles in your skin, known as the ‘barcode’.
In cases such as these it may be more advisable to have an overlay denture fitted, given that, being like a regular denture, it creates a resin gum beneath your upper lip, filling it out and making it look plumper and smoother. The tooth length too can be adapted as required, given that your teeth will continue with the resin gum and we can decide to show more or less tooth or gum as desired.
In any event, today we make fixed porcelain dentures with a false pink ceramic gum and, if you prefer, despite its higher cost, a fixed rather than overlay denture in cases of exaggerated bone loss.
The overlay denture is a magnificent solution when the complete traditional denture refuses to remain in place, and when, due to bone loss or budget, you are unable to choose the option of a fixed denture on implants.
Ask us and we’ll explain the solution most suited to your expectations and circumstances.