It would be lovely indeed if one could solve TMJ Disorder by determining why people clench and grind. Ironically, while many people who clench and grind do develop TMJD, some people who clench and grind never develop this disorder. And, wouldn't you know, some people get TMJD who don't clench and grind at all...ever.
Still, the clenching and grinding of teeth is almost always a contributing factor to the development of TMJD. Since this activity is usually done at night while one is sleeping and unaware of what one is doing, it becomes somewhat of a challenge to break this habit. Additionally, the habit is likely a life-long one.
Childhood Clenching and Grinding This particularly bad habit almost always begins in childhood, as it is quite common for very young children to clench and grind their teeth while sleeping. There are a lot of speculations as to why children develop this habit, and these range from the proverbial stress explanation, to genetics, to diet. For whatever reason children experience nocturnal clenching and grinding of their teeth, however, the habit seems to stop on its own...for most.
Unfortunately, a good many people continue this habit into adulthood. After a decade or two of nocturnal clenching and grinding, it doesn't take much imagination for one to understand why the jaw joints begin to ache, pop, crackle, lock up and in general stage a mutiny.
Diet and Genetics
Increasingly people are looking at diet and genetics as possible causes of this habit. It appears that most clencher/grinders have at least one parent who also does so. But then, one must ask why the parent(s) clench/grind.
Surprisingly, the answer to this question may relate back to the basic diet. Since TMJD is a relatively "modern" disorder, is there something in the diet that makes a person prone to this problem? Weston A. Price, author of Nutrition and Physical Degeneration, would say yes, quite resoundingly. The addition of sugar to our diet has introduced a plethora of modern ailments and debilitating diseases - so why not TMJD? In fact, I once heard a dietician state that had there been an FDA around in the days that sugar was "developed," it would never have been approved, so damaging and addictive is it to the human body. In today's market there is not only the disastrous effects of sugar per se to deal with, but almost all processed foods have high fructose corn syrup added to them.
Will eliminating sugar from one's diet help stop TMJD and nocturnal clenching and grinding? There's only one way to find out, isn't there?