Mary Yaleska, age 11, of Rochester, N  Y  ,

What are teeth made of?

Your pearly white teeth are made of the toughest material in your entire body  They are harder than the nails on your fingers and toes, harder even than your bones  Nails grow long and must be clipped tame and again  Bones may break ‑ and when they do they mend themselves  But when your second teeth are grown in place, they grow no more  If you break a tooth, or get a cavity, it cannot mend or repair itself, If you lose a tooth, you cannot grow a new one, This is why they are made of such durable material  They are meant to last a life time of biting and chewing and gnashing and grinding 

The biggest part of a tooth is hidden from sight, buried deep in the gums, The pearly white part which you see when you look into a mirror is called the crown of the tooth, The pant of the tooth below the pink gum is called the root  It divides into prongs which fit neatly into sockets in the haw bone  The bone socket is called the alveolus, It is lined with a strong, leathery material called periodontal membrane, This lining acts as a cushion and shock absorber to the tooth and helps keep it firmly in place 

The heart of the tooth is an area of soft tissue in the center of the crown and reaching down each of the root prongs  This material is the pulp, filled with nerves and blood vessels  The blood vessels feed the tooth and carry away wastes  The nerves of a healthy tooth do not have much to say, But when decay starts, they whisper a warning when the food you bite is hot or cold, If you ignore this warning and the tooth decays further, the nerves scream with toothache  Both nerves and blood vessels connect with the body's nervous and circulatory systems through tiny holes in the root tips 

The pulpy heart of the tooth is encased in a tough material called dentine, This material, somewhat like very hard bona, makes up the bulk of the tooth above and below the gum line, The outer covering of the root is called cementum  It is as hard as cement, which its name suggests, and the second hardest material iri the body 

The hardest material in the body is the pearly white enamel which covers the crown of the tooth  This is the part of the tooth you keep spanking clean when you brush, and, if all goes well, it should stay that way all your life ‑ which is the way Mother Nature intended it to be  Then what goes wrong? For we are told that 90 per cent of the people of our country have dental caries 

Science has given a lot of thought to the problem of tooth decay and we are beginning to know some of the answers, Decay is caused by bacteria which feed on sugars and produce acids which weaken the tooth enamel, Starchy foods turn to sugar in the mouth and, moreover, we eat 14 times more sugary foods than did our forefathers ‑ who had less dental decay, One cause is most likely too many sweets, candies, sugary desserts and syrupy soft drinks 

Strong teeth tend to resist decay in later years  The body builds them with the meat, vegetables, fruit and daily foods you sat  Fluoride chemicals in drinking water also help  Many communities add one part fluoride to one million parts of their water supply  Less fluoride is no help and more tends to stain the growing enamel.