Introduction

 

The following manuscript grew out of a desire to understand bites. As a philosophy major, I always tried to get to the bottom of things. In dental school,  the bite seemed fundamental to understanding how the teeth work, but explanations of how bites work didn't make sense, and the rationales provided to justify the reverential attitude about preserving every centric bite contact with a level of care that approached worship just seemed contrived. Studies of bites had been mostly concerned with tracking variables that seem unrelated to patient's overall health or even the health of the jaw system. My dental education had made me an effective tooth mechanic but left me without an understanding of how the teeth work physiologically together with the rest of the body. I felt like couldn't see the forest through the trees.

Later, after working in a refugee camp and then living with the primitive hilltribes of Northern Thailand, I noticed that their teeth looked very different from those of my dental patients back home in the US. Their jaw systems showed a functional harmony that I had not seen before. Their dental arches were much wider, their chewing was smoother and more symmetrical, and their TMJs did not click or hurt, - even though many of them had very worn teeth and therefore should have many dental and TMJ problems, according to what I had been taught in dental school. Their chewing seemed easy and enjoyable, in contrast to some of my patients back home, who chewed slowly and with more effort. Also, the relative jaw system health in these tribal people was not just due to the lower stress levels of a simpler life, because the same functional harmony was also present in the jaw systems of the few of them who lived under great stress due to real physical dangers.  

To research what I had seen, I went to museums to study the craniofacial skeletons of people just before the industrialization of our food supply, many from shipwrecks not too long ago. In some of the skeletal remains, especially in those from several centuries ago, both dentitions and TMJs were extremely worn down; and, in a few, they were worn out; but there was no evidence of the unstable bites, irregular condyle shapes, narrow upper jawbones, and backwardly rotating lower jawbones that I was used to seeing in people who eat highly refined foods. In the pre-industrial craniofacial skeletons, the facial frameworks were more forwardly positioned, broader horizontally, shorter vertically, and more symmetrical.  Also their dental arches fit perfectly together over a large area, rather than in only one well defined bite position.

I learned that several dentists who traveled around the world in the first half of the twentieth century to study the teeth and jaws of tribal people had all noted the same change of facial shape in parallel with the dramatic rise in cavities, gum disease, and tooth crowding that occurred whenever they gave up their traditional diets and adopted a diet of processed foods. Weston Price and others showed very clear examples of how, within one generation, the children of parents who had wide symmetrical faces and healthy straight teeth developed cavities, gum disease, crooked teeth, and narrow asymmetrical faces after they moved into settlements and began eating government rations of flour, sugar, and canned meats. 

Unfortunately, these early dental researchers had no way to know which of the changes in diet had caused each of these changes in the jaw system, and some of their work has been misinterpreted. For example, the rise in cavities and gum disease was due to the increase in sugar and flour; but the narrowing and asymmetry of facial form and the resultant rise of TMJ disorders was due the softening of the food. Changes in the same direction can be produced in animals just by grinding and processing their food. Thus, avoiding sugar and flour can certainly prevent cavities and gum disease, but eating processed versions of the same ingrediants that our pre-industrial ancestors ate cannot prevent the retruded and asymmetrical facial growth patterns responsible for TMJ disorders, obstructive sleep apnea, and forward and/or laterally tipped head posture. That would require restoring functional harmony in the jaw system, which requires understanding the bite, the central feature of the jaw system.

However, dentistry has never understood bites, because dental researchers did not develop an understanding of how bites work in other mammals and in our recent ancestors before developing a model of how they should work in our patients today. The model they still use today was developd a century ago, based on the condept of a mechanical hinge, which was needed back then to facilitate labwork. Used in a biological setting like the jaw system, that mechanical model is not reliable enough to create predictable results except when following very narrow and precise protocols. As a result, dental authorities consider all bite treatments to be risky, and they advise dentists to avoid changing, adjusting, or even stabilizing bites. We even allow strained bites to warp the faces and craniofacial structures of our children, while we straighten their teeth for esthetics. Unlike other orthopedic structures, bite tables can be easily reshaped without surgery or risk of infection; but knowing how and when to reshape them requires first understanding how the bite works together with the rest of the body in function and dysfunction, which requires understanding its role in the growth and physiology of the jaw and postural systems, which is the goal of the following chapters. 

The ETIOLOGY chapters comprise a book. It tells a long and fascinating story of how our change to a diet of soft refined foods has altered our facial growth patterns in a manner that has made TMJ disorders and other problems of strained facial growth endemic in modern societies. Chapter 1 describes how our jaw system evolved. Chapter 2 describes how its adaptive craniofacial growth created jaw systems could that fit almost any functional environment. Chapter 3 describes the functional harmony achieved by these natural human jaw systems. Chapter 4 describes how craniofacial growth has changed and how that change has disrupted the functional harmony. Chapter 5 describes the health effects of the changes and the loss of functional harmony in our jaw systems.