Teeth are made up of four different layers which consist of the enamel, dentin, pulp, and cementum. Enamel is the hardest substance in the body and is on the outside of the tooth. The second layer is dentin, which is softer than enamel, and the deepest layer inside the tooth is pulp, which consists of nerves and blood vessels. Cementum is on the root of the tooth and is beneath the gums.
The number and types of teeth a person has changes as they age and health factors. Typically, people have two sets of teeth during their life, primary (baby teeth) and permanent (adult teeth). There are four types of teeth that develop in babies and adults. They include:
1. Incisors
Incisors are the sharp teeth at the front of the mouth that bite into food and cut it into smaller pieces. They are flat with a thin edge. They are also called anterior teeth.
Children and adults have eight incisors, four central incisors at the front of the mouth, two on each row, with one lateral incisor positioned on either side of them.
2. Canines
Canines are the sharp, pointed teeth that reside next to the incisors and look like fangs. They are also called cuspids. Canines are the longest of all the teeth and people use them to tear food.
Children and adults grow four canines. Children usually get their first permanent canines between the ages of 9 and 12. The lower canines tend to come through slightly before those in the upper jaw.
3. Premolars
Premolars (bicuspids) are bigger than the incisors and canines. They have many ridges and help you chew foods. Adults have eight premolars. The first and second premolars are the molars that sit next to the canines.
Young children do not have premolar teeth. These first appear as permanent teeth when children are 10–12 years old.
4. Molars
Molars are the biggest of all the teeth. They have a large, flat surface with ridges that allow them to chew food and grind it up. Adults have 12 permanent molars, six on the bottom and top jaw. Children grow eight primary molars.
The last molars to erupt are wisdom teeth, or third molars, which usually come through between the ages of 17–21. These sit at the end of the row of teeth, in the far corners of the jaw. Some people do not have all four wisdom teeth, or the teeth may stay unerupted in the bone and never appear in the mouth.
Sometimes wisdom teeth can become impacted, which means they can become trapped under the gum and are unable to come through properly. Wisdom teeth that only come through halfway or are in the wrong position can increase the risk for infection or damage in surrounding areas. It is essential to see a dentist if people have any issues with their wisdom teeth.
People may experience mild discomfort when their wisdom teeth start pushing through the gums, but anyone feeling a lot of pain or has swelling should see a dentist. Your dentist may need to remove wisdom teeth if a person has tooth decay, pain, or an infection. People do not need these teeth for chewing and they are difficult to keep clean because of their position far back in the mouth.
Number of teeth
Children have 20 primary (baby) teeth. Primary teeth first start to appear when babies are around six months old. Children usually get all their primary teeth by the age of three.
Baby teeth gradually fall out and 28 permanent teeth replace them. Sometimes permanent teeth push the baby teeth out, but typically, permanent teeth come through the gums at the back of the mouth behind the last baby tooth in the jaw.
The first permanent teeth to erupt through the gums are four first, or ‘6-year’ molars, so-called because they usually come through when a child is about 6 years old. The first baby teeth to fall out are the lower central incisors.
The adult central incisors tend to erupt around the same time as the first permanent molars around age 6-7. Usually, people have lost all of their baby teeth by around the age of 14.
About Thomas Gonzales, D.D.S.
Thomas Gonzales D.D.S. is a Los Angeles dentist with advanced training in dental implants. He has 45 years’ experience and is licensed in IV Sedation. Dr. Gonzales has taught courses worldwide on dental implants at LVI Global, Neodent and Dental Implant Institute. He was a professor of IV Sedation at the University of Nevada, Las Vegas School of Dental Medicine and a neuromuscular dentistry instructor for Loma Linda Medical Center. He is a member of several prestigious organizations, including: the International Congress of Oral Implantologists, American Academy of Implant Dentistry, American Academy of Craniofacial Pain, Dental Organization for Conscious Sedation and American Dental Society of Anesthesiology. Dr. Gonzales is a graduate of the University of Southern California School of Dentistry. He served in the United States Army and is a Vietnam War Veteran.