In order for dentures to work, it is absolutely necessary for them to fit properly.  From time to time, adjustments and relinements will have to be made in order to ensure this fit is maintained.  This is due to the fact that the tissues within the mouth change over time and alter denture fit in the process. 

Often too, dentures rub against the tissues in the mouth.  This can cause irritation, or even sore spots, to develop.  Adjustments can be made to alleviate this condition when it occurs. 

Denture relinement is needed every so often as denture fit becomes noticeably altered.  Jawbones need tooth roots to retain their mass and shape.  When teeth are lost, the jawbone no longer has anything to grow around, and it starts to recede.  There is nothing dentures can do to prevent this (unless they are supported by dental implants).

In some cases, people will lose up to 60 percent of their original jawbone mass within their first three years of getting dentures.   

Bad habits are other reasons that dentures lose their snug fit over time.  When people sleep with their dentures within their mouths, they tend to grind their teeth and clench their jaws.   This can accelerate jaw shrinkage.

Also, believe it or not, weight loss or weight gain can also affect the shape of gums.

Once this affects how the base of the dentures fit the surface of your gums, the person will have to get a relinement for a better fit.  This normally must be done within the first several months they you receive their new dentures.  This cycle of denture relinement then continues for the remainder of the life of the dentures.

Denture replacement has to be arranged every 5 to 10 years or so.  This is due to the fact that the mouth will have changed so much by that time that the old dentures simply no longer fit.  In many cases, old denture teeth can be fitted to a new base.  In other cases, dentists must make an entirely new base with all new denture teeth.

A person should contact their dentist and ask about denture replacement anytime they notice the following problems:   

The dentures are relined, but they still do not fit. 

The mouth feels sore and irritated.

The shape of the face changes

Difficulty chewing foods is noticed have difficulty chewing certain foods.

Dentures fall out while laughing or talking

The denture teeth become worn, or the denture is broken

Headaches or pain are felt in the jaw joints or neck

While relinement and replacement are never fun for denture patients, the importance of a good fit cannot be overemphasize.  When dentures do not fit well, they become loose, and the areas around them become vulnerable to infections, sores, and excess scarring.  Poorly fitting dentures will make chewing more difficult and affect how much your jaw muscles and joints function. 

Dentures that are consistently relined and maintained at a proper degree of fit prevent these problems.  They also keep a persons appearance looking natural and healthy.