What makes a Successful Complete Denture?

What is a successful denture?

Well, let’s say that a successful denture is one that allows you to eat, chew and smile normally without pain, discomfort or worry.

The look of the dentures comes down to selecting the right size, shape, colour and position for your teeth and making sure you are keeping them nice and clean.

The feel, fit and ability to chew comes down to both you and the dentist– both parties play a vital role in successful complete dentures.

The ‘you’ factors include:

• Your Mouth. The anatomy of your mouth is a key factor in the fit of your dentures.

(i) Your ridges:

– Height– if you good high stable ridges then these will help the denture stay in and help stop sideways forces from moving the denture. If you have virtually no ridge (most common on the bottom), then no matter how well made the denture is, it is likely to slide around somewhat with little suction being achieved. How much this happens, will of course depend on your level of muscle control, but in these circumstances, sometimes denture adehesives and implants may be the only solution.

– Consistency– are your ridges firm or squishy (flabby)? If they are firm the denture will not move at all and the seal will be good, if your ridges are squidgy then there will be some movement towards your gums when you chew and this can break the seal. Sometimes surgery is required before making dentures to correct this, if it is perceived to by a big problem.

– Other– are there any other problems that may prevent your complete dentures from sitting and functioning as they should,for example a mandibular or maxillary tori? These may require a surgical procedure to correct.

(ii) Your Muscles– where your muscles attach to your ridges (those responsible for moving your lips, cheeks and tongue) and how they move during chewing, will effect the shape of your denture and your control. See- Neutral zone, below.

(iii) Your Shape– if you have a very high palate it is more difficult to get get suction than a very flat palate- think of the plastic experiment again- the flatter the two surfaces in contact the more difficult it is too separate them. Also the more area for suction, the better, so bigger mouths and anatomy (all else being equal) will give you more grip.

• Your Saliva. As we have said previously- ‘saliva’ is a key ingredient in getting suction. It is not just the amount of saliva but also the quality of the saliva (how thick it is) that affects the suction. If you have dry mouth for any reason, the this lack of saliva will certainly affect your denture’s suction.

• Your muscle control. Muscle control will always be important in your ability to control your dentures during eating and speaking. We are amazing creatures and our ability to learn is just remarkable, though this does dwindle a touch as we get older. The human body is an incredible machine and you will automatically learn (with perseverance) and the various feedback systems we possess, the necessary skills to use your denture. So have faith and it will come. Where anatomy is not on your side- a helping hand may be needed in the form of implants or denture fixative. Remember that even counting to ten was a challenge before you learnt how to do it!

The ‘dentist’ is responsible for constructing a great fitting denture. They need to make sure that the following things are right:

• Maximum contact. Your denture needs to cover the maximum amount of your ridges and palate (the bony parts) without extending too far onto the soft tissues and muscle attachments of your mouth- your cheeks, tongue, lips and soft palate, (the bit that wobbles when you say “arrrr”). We call this the neutral zone and it is where the denture must be made if it is to stay in place and be balanced. If the denture sits on a muscle attachment, for example your lip, the moment you talk and try to eat the denture will jump around like someone on hot sand. To see what I mean grab your lip and pull it down and up in the mirror (video) you can see where the lip attaches, if the denture sits into this movable bit then you have a game of hop scotch on your hands and it will be easily dislodged.

• The bite. The dentist needs to make sure the bite is right and balanced evenly on both sides. Getting the bite right is crucial- if you chew unevenly, biting on one side first for example, will cause the other side to drop down, the seal/suction will be lost and the denture will move. In the same way, biting on the front teeth first will cause the back to drop and air to get in. As dentists, this is exactly how we break the seal when we want to take your dentures out – by applying a little forward pressure to the front teeth. Dentures are usually made, not to contact on the front teeth for this very reason, though as they wear the front teeth often come to contact.

• Peripheral seal. The dentist wants your denture to stay sealed with salival forces connecting it to the gum, stopping air from getting underneath and losing its grip. To do this, the factors discussed above must be right- that’s the bite, the extension and something new called a post dam, must be added. A post dam is simply a little ridge on the back of your denture that presses just slightly into your palate to help keep the seal

• Closeness of the fit. A close fit of the denture base to your gums, means better grip and suction. The more your mouth changes (e.g. when your ridges resob), the poorer the fit becomes and the looser they will be. In such cases, a denture reline can help improve this fit.

In summary, there are two main dentist words associated with making complete dentures: retention and stability. Everything we do, is in one way or another is related to trying to improving these two aspects.

(Note both the‘dentist’ and the‘you’ factors are important in achieving these.)

• Retention. This is the ability of the denture to stay up (or to not drop). It is affected by the:

(i) Closeness of the fit

(ii) Seal of your denture – fit in relation to your muscles and moving tissues

(iii) Contact area- the shape of your mouth and ridges

(iv) Saliva.

• Stability. How good the denture is at bracing itself against forces that try to dislodge it during chewing and speaking. It is affected by the:

(i) The bite
(ii) Your muscle control.