What are the Major Problems with Complete Dentures?

Denture problems can be a result of patient factors- ‘you factors’, ‘dentist factors’ or some combination of both. See- Successful dentures ,for a detailed explanation of these.

The dentist should discuss the ‘you factors’ with you, so that you can appreciate your mouth fully and the limitations of traditional set of dentures. The same grip and experience for chewing cannot be expected if you have no ridges for the denture to sit on, compared to if you have good, tall, solid ridges to hold them in.

Sometimes it is a ‘best possible’ scenario, where we know that things are not in our favour and we just have to do the best we possibly can. It is important the dentist clearly explains this to you, so you have realistic expectations about what can be achieved.

The main denture complaints are discomfort (pain), looseness and problems with adapting to a new set of dentures. There are many possible causes for such problems as you are probably beginning to appreciate, and often more than one thing is contributing.

Below is a discussion of the different issues that a denture wearer can come across:

• Pain – This generally takes the form of ulceration, redness or inflammation. It could be due to a number of causes:

(i) Roughness under the denture– the surface of the denture against your gum is rough or sharp.

(ii) Over-exteneded denture- the denture flange (‘sides’) are too long and dig into your gums.

(iii) Undercuts on the denture not relieved- your ridges are often slightly bulbous in shape and the hard acrylic of the denture is not flexible so it can scrape your gums. This creates pain on putting the denture in and taking it out, often resulting in a nasty little ulcer. This undercut just needs to be indentified and smoothed, then the denture left out at any opportunity while this heals up- generally about a week.

(iv) Lack of freeway space- if your denture teeth touch when you your mouth is totally at rest (just after you swallow), this can causes your muscles around your mouth to be in constant tension causing pain.

(v) Errors in the bite– uneven chewing can cause pain and pressure in certain areas or lead to looseness.

(vi) Grinding- if you grind on your dentures, in the same way that if you did it with natural teeth you are putting your gums, mouth and muscles under considerable pressure and stresses.

(vii) Movement of the denture- see- Looseness, below

(viii) Resorbtion

(ix) Mental nerve pain- you have a nerve supplying sensation to your lower lip and jaw that sits nicely hidden in bone when you have teeth. Over time, resorbtion of the ridges can mean that this nerve comes to lie on top of the ridge in the premolar region. This can be painful to any pressure from the denture often requiring a soft lining if it happens.

(x) A warped denture- doesn’t fit and sit down properly

(xi) Retained roots or bony tori- toriare bony areas that occur in the palate (roof of your mouth) and on the inside of your lower jaw opposite the premolars. They can potentially effect how the denture sits down if they are large and may need to be corrected with surgery before making your dentures. Tori have very little gum overlying them to cushion the denture, so can often be painful to pressure from the denture if the denture hasn’t been adjusted to give sufficient space around them.

(xii) Xerostomia- a lack of lubrication can cause friction and inadequate suction.

(xiii) Not enough space for muscle attachments. If you hold up your lip, you will see muscle attachments that connect your cheeks and lips to your gums (ridges). As your ridges resorb over time, the muscle attachments will come to lie higher up, and if the denture doesn’t make way for these, impinging on them, it will certainly rub and move the denture.

• Looseness. You may feel the dentures are rocking, falling (if it is an upper) lifting or shifting (if it is a lower) or feel like the dentures are just too big. As we have seen, this could be due to ‘you factors’ such as poor ridges, difficult high-up muscle attachments, not enough good saliva or poor muscular control. Or it could be faults with the denture, such as the teeth not being in the right position, an uneven bite, problems with the extension of the denture- too short or too long and so not achieving a good seal at the border- ‘peripheral seal’ This is most commonly a complaint with the lower full denture, which is easily dislodged by the the tongue, lips and cheeks when poor resorbed ridges are present.

• Appearance. You may feel the denture doesn’t look right because of things friends or relatives have said- the teeth are too big or small, too light or dark, you show too much tooth or too little, they are too even or too irregular, the lip may be too bulky or not supported enough, the colour of the denture base (gum coloured acrylic) may be felt to be unnatural – any number of possibilites. Not a lot can be done once the dentures are processed from wax to acrylic. This is why at the trial stage, it is so important to speak your mind. If in doubt, bring your partner or relative with you to the appointment so they can give you their opinion.

• Cheek biting. Often when you have a new set of dentures, this can happen and as you know once you bite your cheek, it swells up a bit and makes you more likely to bite it again. Your mouth and muscles will learn how to bite with them, you just need to take it slowly when chewing to begin with and allow your brain to work things out. If cheek or lip biting continues it may be that the width of the denture in the cheek or lip area isn’t enough to hold the soft tissues out of the way. If the teeth aren’t in the right position (neutral zone) then some adjustments to your bottom denture teeth may be necessary.

• Gagging. For full dentures this can pose a bit of a problem, since we identified earlier that the more surface area on the denture- the better the grip and suction. The more you take away from the base of the top denture, the worse the retention. So when you ask your dentist to grind out the middle, you need to be aware of how this can effect them staying up. If you have a partial denture then there is generally a bit more that can be done, since some retention is gained from the teeth and the design can be adjusted, to cover less of the sensitive areas. Implants and a smaller denture that attaches into them or a fixed dental bridge is a possible solution. Some people are just more susceptible to gagging than others and it is not uncommon for someone to have problems even cleaning their own teeth. If it occurs after a while of wearing the dentures (so not an initial psychological reflex) it may be due to looseness or the denture rocking. If you are having problems with a new set, the palate (roof) of your denture could be too thick, the post dam too far back, the top teeth placed too far towards the inside (palatally) or too far down so they contact the tongue. These possible causes would need to be investigated by your dentist.

• Fracture. Aside of ‘accidental’ reasons, such as dropping your dentures or a bang to your mouth, dentures can fracture from the stresses of normal use if the acrylic becomes fatigued. If the denture repeatedly flexes because it isn’t fitting closely (e.g. due to resporbtion or because of flabby ridges) or from an uneven bite, this will create extra stress. Some of you, simply generate one hell of a force when you bite and grinding is also bound to take its toll. If you have very prominent muscle attachments, your denture may need to be deeply notched (relieved) in this area so they don’t rub or displace the denture and this can weaken the denture considerably. Thin dentures are more likely to fracture than thick dentures and where fractures occur repeatedly, it is possible for the technician to incorporate a metal plate to give this some extra strength.

• Teeth coming off. This can happen occasionally. Normally it is just a single tooth, which can be stuck back in by the lab technician. If this happens, assuming you don’t accidentally swallow it, you must bring it with you to your dentist- it will make the whole process easier, faster and cheaper.

• Wear of teeth. After wearing your denture for a number of years, the teeth often become very flat with no normal pattern or ridges on. This can make it more difficult to chew food. If you already have a denture take it out and have a look- do the teeth still have patterns on them or are they smooth and rounded. If they are and you have trouble chewing food this may be part of the problem.

• Resorbtion. Your bottom ridges tend to wear down more quickly than your upper ridges but both will naturally resorb somewhat overtime with the pressures of chewing. As your bone shrinks down, the denture fit will obviously get worse, and this lack of a close fit, will lead to less grip and stability and more movement in your dentures.

This can cause:

(i) Further and faster resorbtion

(ii) More difficulty chewing and speaking normally

(iii) Inflammation of your gums

(iv) Possible infection, such as yeast infections (candida) denture stomatitis or angular chelitis

(v) Burning mouth sydrome- This condition described as a ‘burning’ or ‘tingling’ sensation may caused by a lack of freeway space when your mouth is at rest, the height of your dentures being too much (occluso-vertical dimension) or due to a sensitivity to the monomer in the acrylic base.

• Angelar chelitis. This is an infection of the creases, at the corner of your mouth. It could be that there is not enough lip support from the dentures, that the dentures are too small in height (making you over close) or a problem with the position of the front teeth.

• Bite problems. An uneven bite (biting one side before the other) may cause tilting of the denture and/ or it to lose suction and drop during eating. Teeth can catch, as you try to close into a normal bite (this is called a ‘premature contact’), from which you slide into a comfortable bite position. This happens when the teeth haven’t been made in quite the correct position (RCP), and some adjustment to the bite is likely to be needed.

• Diffiuclty eating. Unstable dentures may move during chewing, causing soreness and problems. It is important to maximize all the features that provide grip or retention and minimize any displacing forces. Sometimes chewing can be a problem- ‘eating steaks’ for example can be difficult with blunt teeth or where narrow teeth have been replaced with wider teeth, or cuspless teeth, or teeth have been ground down to make the bite fit,. All of these changes will affect how you manage to crush your food. If you are struggling to open wide enough to put food in, then some issue (e.g. the dentures are too high to tolerate, or as a consequence of TMJD) is affecting the muscles around your mouth.

• TMJD. This is a painful click on opening or closing, or a tenderness in the muscles that control your jaw. It most commonly occurs from large changes to the vertical height of your new dentures beyond your adaptive capabilities and often gets worse throughout the day. It could also be, that your denture is too thick around the tuberosity region (back top area) preventing the normal movement of your jaw during opening and closing.

• Speech. Sometimes a new denture can effect your speech, most of the time it just takes you a little time to adapt. Very occasionally, you may have persisting difficulty with f, v, d, p, b ,s and t sounds, if the position of the front teeth is considerably out.

• Noise. Some noise from chewing with your dentures is normal, but considerable clicking from the denture teeth may indicate:

(i) The denture height is too much (excessive OVD)

(ii)There is not enough retention (due to the denture, lack of muscle control- sometimes both) so they are dropping and making a sound.

(iii) There is interference in the bite.

• Denture hyperplasia. Over-extension of the denture is common if the ridges have resorbed and then denture now sits lower down than it did before. This can cause looseness, soreness, swelling and ulceration. It can also cause hyperplasia (an overgrowth of gum) as a result of long term irritation- this is often painless but some patients get worried that this growth could be oral cancer because it can look a little scarey. The treatment is for the dentist to identify the overextended areas and correct it. Sometimes a soft lining is needed initially during the healing period, then a new denture should be considered.

• Allergy. Very occasionally this occurs to the unreacted monomer in the acrylic, if an error with the final processing stage occurs.