Dental Functional Morphology: How Teeth Work (review)

Who can get excited about teeth? How do teeth work? Why write a book about how teeth work? These are just a few of the questions that are asked in the preface of Peter Lucas's outstanding work on dental functional morphology. The answer to the first question is that lots of people would find this work interesting and informative, including physical anthropologists, a broad range of paleontologists, and anatomists. If you are a researcher interested in studying the evolution of teeth over a broad geological scope and want to be aware of discussions about the forces that have shaped teeth in humans (and a diverse range of other species), then Dental Functional Morphology is a book you should have.

Beginning with the preface and other information preceding the main body of the text, there is a clear sense of how passionate Lucas is about his research, how many diverse avenues of investigation are available in studying dentition, and how much fun it can be to discuss them. A perfect example of this is an innovative presentation of the evolution of the human molar that causes immediate involvement with the book. We are not given a static diagram that tracks 300 million years of change from simple cone to multicusped molar. Instead, we are given a "flick art" or "flick-page animation" situated in the lower right-hand corner of the page, beginning on page xv and continuing to page 159. An explanation of the flick art is given on pages xv and xvi, in which Lucas cautions us about the idealized forms seen in the presentation and what we are seeing as we speed through 300 million years in a few seconds. There was much work put into this presentation, and I am hesitant to say anything negative about it. However, if additional information (e.g., particular species represented and the geologic time ranges when they were present) could have accompanied some of the drawings in the lower-right hand corner, the flick art would be an even more useful, and fun, teaching tool.

Chapter 1 is titled "How to Get Excited About Teeth." Lucas takes us through some interesting and familiar topics here. The chapter begins with a brief presentation of the debate of the origins of teeth. Did they begin as dermal scales or not? This is followed by a discussion of why teeth are so important, especially to mammals in comparison to other vertebrates. And, we are reminded of the distinct changes in the human diet that have occurred over the last few thousand years and that have been detrimental to our dental health. Lucas continues the chapter with a discussion of how teeth are involved in the basic functions of chewing and swallowing, sensing food, and communication. He then limits the scope of the remainder of the book to the function of teeth as they are involved in ingesting, chewing, and swallowing food and how the properties of food drive the evolutionary changes in tooth form.

Chapter 2 is a strong and engaging presentation of the structure of the mammalian mouth. At first glance the terminology and description of anatomy seemed a bit brief. But, as one continues through the chapter, Lucas provides well-written explanations of tooth structure, the individual tissues that make up the teeth, jaw, tooth socket, and the like, and then adds information on such subjects as the workings and anatomy of tongue muscles, facial muscles, and neck muscles for a complete overview. Consistent with the broad perspective of the text, there are numerous, intriguing comparisons of anatomy between different mammals and between mammals and reptiles.

In keeping with another theme of the book, there are also opportunities to be actively involved with the subject matter. An example of this is the "game" illustrated in Figure 2.18 that helps the reader to understand the arrangement of jaw muscles in mammals. In this game two people manipulate a jaw to understand how different controlling muscles work...