Introduction

 

DENTAL OCCLUSION, FACIAL GROWTH, AND TMJ DISORDERS

The following manuscript grew out of research motivated by a desire to understand dental occlusion. Dental school had taught me guidelines for treating bites, but the rationales provided to justify those guidelines just didn't make sense.  Research on bites had been mostly concerned with tracking variables that seem unrelated to patient's overall health or even dental health.  My dental education had made me a good tooth mechanic, but it had not taught me anything about how the teeth work together with the rest of the body.  I felt like dentistry had failed to see the forest through the trees.  

Then after working in a refugee camp, I went to live with some of the relatively primitive hilltribes in the North of Thailand, and I made an interesting discovery.  Having recently graduated dental school, I still watched closely the movement of people's jaws when they talked and chewed.  The hilltribe people had worn their teeth down significantly.  From everything I had learned, they should have pathological masticatory systems.  However I noticed their chewing was strong and efficient, and their faces were very symmetrical.   Examination of their masticatory systems showed no sign of the clicking and other pathologies which were common in my patients back in the US.   The difference was not just a lack of stress in these hilltribes.  There were some people who lived under great stress for various reasons, and they exhibited the same healthy harmonious masticatory systems.  That discovery led me to undertake some years of anthropological research in an effort to get to the bottom of this mystery.  I spent a lot of time in museums and with my face buried in the American Journal of Physical Anthropology where a great deal of good research had already been done.

I realized that, to understand why TMJ disorders have become endemic in modern society, they must be seen in the context of the evolution of the human masticatory system.  They arise all over the world within one generation whenever societies abandon their traditional life styles and adopt a diet of sweetened refined foods. Before the industrialization of food, there was no evidence of the types of TMJ disorders that are common in modern societies today. In the thousands of intact human skulls in museums as well as in the few tribes still living traditional life styles, we can see evidence of arthritic degeneration of the TMJs associated with injuries and extreme tooth wear, but we see no evidence of the dislocated disks, strained and unstable dental occlusions, or asymmetrical retrognathic backwardly rotating facial growth found in many modern TMJ disorder patients.