Procedure Part 2

Secondary Impressions

The primary impression is taken with a stock tray- 3 sizes fit all. These are ready made trays that come in small, medium and large and very approximately fit the size and shape of your mouth.

Secondary impressions are mostly taken with what is known as a ‘special tray’. This is a tray that is constructed on the model of your teeth to fit your mouth and no-one elses. It allows for overupted teeth and those that are out of position and is extended to record the full detail of your sulcus (where your jaw and cheeks meet.

Sometimes if the primary impression is that good and no teeth modifications are needed, you can get away without having to have a secondary impression.

The material used for this will depend on the choice of the dentist and the practice. I tend to use a silicone based material or sometimes alginate again, but each to their own- every dentist has their preferences!

Taking a shade- The shade of your existing teeth must be taken by the dentist so the denture can be made to look as natural as possible. If you want to consider whitening your teeth, this must be done before your denture is made since the denture teeth will not change colour and replacing them is almost as difficult as making a completely new set.

The size and shape of your teeth should also be chosen. If the denture is only replacing posterior (back) teeth, then generally the technician will select the best, based teeth on the existing teeth and the space available.

If it involves your front teeth, you may want a little more say in the decision. A single missing tooth generally would just be matched as accurately as possible. If you have a few missing front teeth and like the teeth on your existing denture, a mould can be taken and sent to the lab for copying and replicating these on your new denture.

If you have any photographs of how your teeth used to be, or features that you would like copied into the final design this can be useful- though some age-related changes may want to be taken into account. For example, the amount of incisor tooth that shows below your top lip at rest would be much greater in a person in their twenties compared to someone in their late middle age.

If the denture is to replace a front tooth or teeth, any twisting, tiliting or spacing can be incorporated if you would like it to be. If you have always had a gap between your front teeth, it is likely that you will want to keep this as it is what makes you, you- it’s part of your identity.

Don’t worry, you will get a chance to review your choices and change them if you don’t like them before they are final.

Try-in of the Metal Framework

Obviously this is only needed if you are having a cobalt chrome denture and sometimes this stage is combined with the next stage of the wax try- in.

Here the dentist will check that the metal framework fits well, that the position of clasps and rests are good and that the bite is right or unchanged with the frames in place.

Some small changes may be made there and then whilst you are in the chair, bigger changes may need to be communicated to the lab or worst case scenario a new impression taken if something appears to be rather significantly wrong.

Sometimes a new bite may be recorded at this stage.

Try-in of Wax Denture

We are getting there! At this stage, you can see and feel what the final denture will look like. The teeth at this point are only held in by wax so any changes can be made if you don’t like them.

The dentist will try each denture in separately (if you are having more than one) and then together. They will check the bite, check the position of the teeth and adjust any areas where the base of the wax is too thick or over extended. Small adjustments can always be done when the denture has been processed and finished but bigger changes are easier to do at this stage.

They may ask you to count to 10 to give them idea of the position of the teeth and how it will effect your speech. If the ‘freeway space’ (see- Complete denture procedure for an explanation) is too much or too little, it can affect the ‘S’ sound.

Once the dentist is happy they should sit you up and give you a mirror to have a look- what do you think? Be honest! They (and the nurse in my opinion) should have an open discussion with you about any worries and concerns you have, how you feel about the colour of the teeth, their size and shape, if anything is hurting, how they generally feel. Now is the time to speak up!

Often a patient will say that they are happy and I will mention that the actual centre-line, (middle of their front teeth) is a little to the one side, or the colour is a little light or dark. Sometimes they say-“No it’s all good, I like them how they are,”-other times, once it has been brought to their attention they want to change it – and we do.

You are the one who has to wear it, not the dentist. So if you are not happy, say so. It is much easier for us to make changes now compared to when the denture is finished. Sometimes I may need 2 or 3 try-in appointments to get it right and have the patient happy- if that’s what it takes, that’s what it takes. You are paying for the service and believe me the dentist wants you to be happy.

Some dentists will make you sign something to say that you are happy with how they look- They just don’t want you to turn round in two weeks and say I think they are a little too dark because there is little they can do at that point.

Bear in mind, if you have large areas of wax on the try in (i.e. the denture is mucosa- bourn )and replacing many missing teeth), you get very little suction compared to when it is in acrylic. This means they will often be more loose at this ‘try in stage’ than when they are finished. That’s not to say that these types of dentures will have perfect grip when they are finished- they are notoriously less grippy than other options. I’m just saying that most of the time there will be a noticeable improvement.

In the same way that complete dentures in wax have little or no suction, they need the acrylic of the final denture to be properly wetted with salvia (which can take a few days) before they start to get grip a bit better and achieve some suction.

When you are happy and only when… the denture can be sent off to be finished.

Finish or Fit Stage

Finally the day arrives after a few weeks when the denture has been processed and the wax is replaced with acrylic. The dentist will go through all the stages again like for the try-in checking each aspect of the denture.

Any undercuts that may scrape your gum will be removed, the extension and bite checked and adjusted and the instructions on how to care for your denture discussed.

The dentist should show you how to put the denture in and take it out ensuring it isn’t too loose or to tight. The denture is generally made with a specific path of insertion– this means it only goes in and out in one way and you need to learn this. For example, you may need to seat it first at the back and then at the front- trying to seat it at the front first simply won’t let the denture sit down in the right place.

Even though it may be a bit tricky to get in and out to begin with, as long as you can do it whilst in the dentist chair, you will be able to take it out for cleaning when you get home. I have had a few patients get stuck because they have forgotten the right path of insertion or removal, but once you have done this a few times you will have it off pat.

If the denture is very tight to begin with don’t worry it will loosen a bit over time. If it is loose then the situation needs to be evaluated and adjustments made if possible; some muscular control may need to be developed as part of it. Or the dentist may just need to activate the clasps a little more, so they grip tighter.

I often suggest wearing new dentures at night for the first week, just to get your mouth used to dimensions and having them there. But as a general rule, dentures should be left out at night.

If the denture or dentures are particularly sore or painful during the first week, they should be left out and only worn for a few hours before your appointment as this can help us (dentists) locate the sore spots more easily. Sometimes it will show a little red mark or ulcer, sometimes an area on your gum will just be sore to pressure.

Now that you have your denture made and comfortable, is that it?

‘Yes but no but…’ as my favourite Little Britain character would say. As we discussed earlier, wearing a partial denture has risks. It is even more important, that you see your dentist regularly for a check of your teeth and denture and a good clean.

In addition to the routine checks for dental decay and gum disease which can be more of a problem if you are wearing a denture and not looking after things appropriately, the dentist needs to check no damage is being done your oral tissues from the denture itself and that everything is functioning as it should. They will also advise you on any areas where you need to step up your oral hygiene or this will lead to problems.

Dentures on average can be expected to last about 10 years depending on the situation. Over this time period, sufficient changes are likely to have occurred, (worn teeth, shrunken ridges etc.) to affect the fit and function so a new denture is required or in some circumstances only a reline may be needed. It just depends- I see some patients with little signs of wear and still a perfect fit after 15 years (though rare) and others who after 5 years their denture looks like it is an ancient artefact.

Regular visits are needed to monitor these changes- If left too long, your denture and natural teeth may have worn and moved and this can create problems when it comes to replacing the denture. Your jaw and muscles may have got used to this situation and opening you back up to restore the height of your smile and face may not be as simple and easy for you to adjust to.

As weird as it seems considerable damage to teeth and gums can happen without you knowing… they don’t always give you pain- at least not until its quite late, perhaps too late to do something. As an example, we sometimes see a patient who hasn’t been for a number of years and on the screening X-rays we discover a cavity that has gone into the nerve of the tooth undetected- it gave little or no symptoms that the patient noticed and it is too late for a filling. You can imagine it comes as a bit of a shock to hear me say,“Unfortunately the tooth needs a root canal treatment or to be extracted.”

Also problems can occur as you go along (of course this will vary from patient to patient) – a clasp may break, another tooth may need to be added, a new filling affects the fit- all these things can be dealt with by your dentist as they arise. Check out –Repairs and adjustments to partial dentures

Denture Review

Dentures take some getting used to… this is a normal. There is a learning curve to gain the necessary control to use them effectively.

If this is the first time you are wearing a partial denture, they will feel very foreign and strange and as much as you want to leave them out it is important to persevere. It will soon feel normal with them and abnormal without them, but you must stick with it.

During the first few days you may find:

  • There is an increase in the amount of saliva in your mouth
  • A bulky crowded feeling
  • Some sore spots and areas of pressure
  • The denture is uncomfortable
  • You bite your cheek a couple of times.

If this is not your first set then, you will already have developed some muscle control so it is a matter more of adapting to your new denture- it may be a new design, a different type, have more teeth on it or have increased the height of your bite- however subtle the changes, it will as you know take a little time to ‘bed in’.

It is expected that a new denture will rub in a couple of places, get a bit sore and need you to pop back to the dentist for a few adjustments. This is not because the denture is badly made, just that the impressions provide a static model or your mouth not a moving one, so we cannot predict exactly how and where your muscles connect and how their movements will affect the denture.

I generally arrange an appointment to check a new denture after 3 days, where I can ease the painful spots. Sometimes a few visits are needed to get it just right- you don’t want to go grinding away too much too quickly as this can affect the fit.

The amount of muscle control needed depends on mostly on the type of denture you have had made. Cobalt chrome dentures and flexidentures tend to have very good grip and as such require less control than a standard acrylic denture or a full denture.

The more teeth on the denture and the less stable the denture design, the more muscle control that will be needed. That is why often a partial denture is good training for wearing a complete denture because it not only gets you used to wearing something in your mouth but it helps you begin developing the necessary muscle control.

To develop your muscle control, I suggest you cut up your food into small pieces and go for softer less sticky foods initially. A nice big juicy rump steak straight off is not the most sensible or realistic option but more something you work towards. Make sure you chew on both sides slowly, to begin with. It doesn’t hurt to do this carefully and consciously, you are giving your brain all the information to do this automatically in the future.