Dear College of Science Faculty and Staff,
My second-grade friend Beverly and I were playing an innovative follow-the-leader game around the house, one with eyes open leading the other with eyes closed. Walking side by side, Beverly leading me, I suddenly collided hard with something, jolting my head and front teeth. Turned out, Beverly had walked through a door, and I had walked into the wall beside it. My mom drove me to Dr. Hotz the dentist, who said luckily the teeth were not shattered, although one front tooth was missing a chunk and there was a crack across the one next door. The chunk is still missing, the memory indelible.
Teeth are an extraordinary invention. Before, animals had to eat soft, liquid-ey foods. The view is that teeth evolved from ‘dermal denticles’, triangular structures in skin which folded in to become part of the mouth. Teeth first arose in animals without jaws, who use them to tear food; and took off with the advent of jaws, that allow biting and chewing, and formation of the different types of teeth needed. Sharks are lucky enough to continuously make new teeth, replacing those that break off, but humans have only two sets. Interestingly, your adult teeth formed long before birth and waited below the baby ones for their opportunity to emerge.
Each tooth forms from a tight sheet of cells that has a conversation with a looser knit group, and together they decide to make a tooth bud (see image below). The bud grows and forms ‘enamel knots’, which dictate whether the tooth will have one cusp (like your front teeth) or multiple (like your molars). Many people lack some adult teeth right from birth, and many adult teeth decay and are removed, but alas do not regrow, as you know. Engineered tooth substitutes, like implants, are clever but not as good as the real thing. The grand goal for biologists in the field is to figure out how teeth can be coaxed to regrow right in the mouth where they are needed. That is for the future, but cells can now be grown in the lab into ‘tooth organoids’, tiny parts of the developing tooth, that may pave the way for tooth regeneration. It’s a difficult goal, and some of our brilliant College of Science researchers work in related, crucial areas.
Tooth Formation
Thesleff, 2013 https://onlinelibrary.wiley.com/doi/10.1111/adj.12102
Teeth are so pivotal, that multiple idioms employ the term: ‘get one’s teeth into’, ‘has some teeth’ for example. Our Northeastern College of Science has teeth for sure, as we promote the Good Power of Science at every level, and we definitely get our teeth into doing so. It was outstanding to come together at the in-person Community Meeting this week (slides here), and as we discussed, please get your teeth into our Strategic Plan CONNECTIONS to the Future.
THANK YOU for everything you are contributing this semester. Please take a well-deserved break for Thanksgiving, and I hope you have a peaceful and pleasant holiday.
The Weekly will return on December 2.