What is the Procedure for a Complete Denture?
Making a complete denture is not as simple as you wold imagine (to get right at least!. Anyone who has worn them will testify to this. Patients experiencing problems with their teeth, often say… “Doc, wouldn’t it be easier just to rip them all out and give me falsies”…. Simple answer, “Not on your life!”.
Obviously when making a new complete denture, we don’t have to consider any of the teeth (because there aren’t any) which makes the design easier than a partial denture; it’s simply a complete denture.
What is the Sequence of Events for Making a Complete Denture?
The procedure for making a complete denture is as follows:
- Emergency treatement. If you have broken a tooth or the denture in half, or if it is hurting in some way- it is best to get this sorted first so that you have something comfortable to wear whilst a new set is being made. In my opinion, it can always be a good idea to have a spare set, since you never know what might happen, and where you will be.
- Examination and treatment planning
(i) Your dental and medical history.
(ii) Patient and denture assessment – soft tissues, hard tissues and your current set of dentures, including what features you like and what you would like to change?
(iii) Discussion of expectations, complete denture costs and making a treatment plan.
- Surgery (if needed). Such as removing a decayed retained root or for specific problems with your gums or ridges that may effect making your dentures. We want the most time for healing before making a new set. Surgery also includes placing implants if you are having them.
- Making the denture
Note, The procedure for an immediate complete denture is slightly different as you cannot try the denture in, in the same way.
The stages for a standard complete denture are as follows:
- Primary impressions. Similar to taking them for a partial denture, except this will involve using a different type of tray to accommodate the fact that there are no teeth. Zinc oxide eugonal, impression compound, alginate or silicone materials may all be used depending on what the dentist prefers. The key here is to get the full extension of where the denture will sit in the impression and this may involve modifying the borders first with something called greenstick to make sure your muscles attachments are nicely recorded. I like to wipe alginate all up inside the lips and cheeks to stop air bubbles- gets a bit messy but gives a good impression.
- Secondary impressions. These may not be needed if the stock tray and first impression is good enough. If it isn’t, a special tray that fits the individual shape of your mouth will be requested from the lab and a new impression taken- this is called the master impression and it will be poured up to make a model of your mouth on which the complete denture will be made. When taking impressions the dentist needs to mould the impression to the muscles of your cheeks, tongue and lips. To do this they will gently pull and massage them whilst holding the tray down and ask you to stick your tongue out and from side to side. They may ask you to purse your lips, say ‘ooooh’ and ‘eeeeh’ and swallow. There are time when modifications to the techniques may be needed e.g. for a flabby ridge.
- The bite. If you only have all your teeth missing in one arch the process is slightly simpler and a combination of the description here and the one for partial dentures is used. What I am about to describe is for complete dentures on the top and bottom- it is one of the trickiest things to get exactly right in dentistry. Because you have no teeth, you have no natural biting position so we have to use the only reproducible position you have- RCP which I explained. See- Partial dentures. Here we will use two wax bite blocks to record how you close your jaw together and give the technician, the necessary information to set up your teeth. This includes:
(i) The amount of lip support. We don’t want too much support so that you look as if have a fat lip, or too little so that your lip creases up, making you look older.
(ii) The position of your teeth.
– The centre line
– The biting surfaces of your teeth (‘occlusal plane’)
– How much tooth will be showing in relation to the lip- this decreases with age because of facial changes and tooth wear.
(iii) The height of your dentures (called the occluso- vertical dimension or OVD) – too tall and it will put stress on your muscles and not allow you to relax and close properly, too small and you will overclose, causing creases in your face and the potential for angelur chelitis.
We have our ways for telling what the right height is:
– We can use your exisiting dentures as a guide and open you up a few millimeters to replace the space that you have lost due to wear. We can’t do this too much otherwise you may have difficulty adapting.
– We can measure it. It is important that your teeth aren’t always in contact- if you have teeth, try this test- just swallow, relax and stay still with your lips closed- are your teeth meeting? No, this is called your freeway space, and is important because it allows the muscles of your face to relax. If you now bite together, the height of your face will shrink just slightly as you close this space. We can use this knowledge to work out the OVD by measuring your resting face height and taking off 2-4mm which is the average amount of freeway space someone has.
Recording the occlusion or bite is quite time consuming. The dentist will need to put them in and out of your mouth a number of times as they try to get the various elements correct. Wax will need to be added and taken away and the height of your face measured with a willis guage, calipers or a ruler. There will be lots of staring at your face from all angles to ensure the rims are the right thickness for your lips and shaped at the right angle. The centre of your face will be marked carefully with a wax knife- you don’t want your teeth off to one side like Tom Cruise.
Eventually when the rims have been trimmed to the right dimensions, the dentist will record your RCP or reproducible biting position by getting you to curl your tongue back as far as possible and gently manipulating your jaw backwards and upwards. They will soften the wax or use a quick setting bite recording paste to stick the two rims together. Then there is just the matter of taking them out in one piece- yes there is space ; it can sometimes help if you gently encourage it with your tongue. Done!
The shade, shape and size of your denture teeth also need to be recorded at this time.
Are there any special requests? I have a lady who wanted a small gold inlay placed on her lateral incisor to mimic the tooth that was being taken out. More commonly I get asked to twist the teeth slightly so they look less perfect and more natural. If you want to go the whole hog, you can even get fillings put into the denture teeth but it will cost you!
- Try in. See- Partial denture- try in stage. It is not uncommon to have more than one try in appointment to get things right. The dentist may take off or reposition some or all of the teeth in the process, and send the denture back to the lab to be re-set. Now is the time to make comments about the size, shape and colour of your teeth because once they are finished they are finished. Only when you and the dentist are both happy should the denture(s) be finished in acrylic. Don’t worry too much about the suction at this point- wax doesn’t grip well at all compared to acrylic so they often drop a little at this stage.
Note. If you have a history of fractured dentures because you have a particularly strong bite (not from just from dropping them!) then it is possible to put a metal plate into the denture to help strength it.
- Fitting. So you finally have the denture or dentures to take home with you! I bet you didn’t think it was such a long and involved process- helps you appreciate the cost a little more doesn’t it! See- Fitting a partial denture for more details.
- Aftercare. The dentist will discuss how to care for your dentures and maybe provide you with some written instructions to help jog your memory – it can be difficult to take it all in at once.