Dental Health The Functions of Molars and Wisdom Teeth Molars are the tough workhorses of human teeth By Shawn Watson Shawn Watson Shawn Watson is an orthodontic dental assistant and writer with over 10 years of experience working in the field of dentistry. Learn about our editorial process Updated on January 21, 2023 Medically reviewed by Edmund Khoo, DDS Medically reviewed by Edmund Khoo, DDS Edmund Khoo, DDS, is board-certified in orthodontics and is a Diplomate of the American Board of Orthodontics. Learn about our Medical Expert Board Fact checked by Nick Blackmer Fact checked by Nick Blackmer LinkedIn Nick Blackmer is a librarian, fact-checker, and researcher with more than 20 years’ experience in consumer-oriented health and wellness content. Learn about our editorial process Print Table of Contents View All Table of Contents Types of Molars Why Wisdom Teeth? Problems Frequently Asked Questions Molars are rounded, flat teeth in the back of the mouth. They include your wisdom teeth. Also called molar teeth, molars can vary in size and shape but are the largest teeth in the mouth. Their role is to grind food into pieces that are easy to swallow, while the smaller, sharper front teeth are used for biting and tearing food. This article looks at the types of molars you have, why you have wisdom teeth, and problems that can develop in them. Zinkevych / Getty Images Types of Molars The average adult has twelve molars, three on each side of both your upper and lower jaws. Each of the three molars is a different type: First molars, also called six-year molars because they come in around age sixSecond molars, also called twelve-year molars because they erupt around age 12Third molars, also called wisdom teeth, which appear between the ages of 17 and 21 Molars are designed to sustain great amounts of force from chewing, grinding, and clenching. That's thanks to their large surface area and two to four roots that are firmly implanted in the jaw bone. Why Do We Have Wisdom Teeth? The third molars, or wisdom teeth, are vestiges from our evolutionary past when the human mouth was larger and could accommodate more teeth. They were useful in chewing especially coarse foods, such as roots, nuts, leaves, and tough meats. This type of diet was tough on the teeth—especially without the helpful maintenance tools we enjoy today, such as toothbrushes, toothpaste, and dental floss. So our ancestor's teeth were subject to significant wear and loss due to tooth decay. Modern humans don't eat foods that require these extra teeth. However, evolution hasn't yet caught up to this change, so people still get those extra teeth around the time they reach adulthood. Not Everyone Has Them About 37% of people never develop wisdom teeth or don't have all four. Some experts believe this is due to evolution. The Problem of Wisdom Teeth Wisdom teeth have become a problem because evolution has shrunk the human jawbone. This presents a range of problems when those vestigial wisdom teeth try to squeeze in. As wisdom teeth form, they can become blocked by other teeth so they can't come in properly. This is referred to as being "impacted." If a wisdom tooth does come in, it can crowd the mouth and create hard-to-clean places where bacteria can thrive, leading to serious infections of the gums and surrounding tissue. Wisdom teeth may also never come in. This can lead to cysts or tumors that can do considerable damage to the jawbone (mandible) and teeth if they're not taken out. These problems are among the reasons many people need to have their wisdom teeth removed. This surgery is generally recommended for young adults, which is often early enough to prevent or minimize complications. In some people, wisdom teeth come in without any problems. One study suggests that's the case for about 15% of the population. Even in these cases, the wisdom teeth may need to be removed to avoid problems that might develop later in life, when surgery has longer healing times and more potential for complications. Summary Molars are the big flat teeth in the back of your mouth. They're designed to crush and grind food and can withstand considerable force. The three types are six-year molars, twelve-year molars, and wisdom teeth. The modern human diet no longer requires wisdom teeth, so they're called vestigial, meaning they're left over from an earlier time. The human jaw has shrunk through evolution, which means there's often not enough room for wisdom teeth to come in. That can lead to various problems and most people have their wisdom teeth removed at some point. The surgery is safer and easier to recover from when you're young. Frequently Asked Questions What causes pain in the molars? Some causes of molar pain include:CavitiesBroken or cracked toothAbscessed toothDamaged fillingGrinding your teethContact your dentist if the pain is severe or lasts more than one or two days. Make an appointment right away if you also have swelling, fever, earache, or pain when opening your mouth wide. Learn More: Causes of Tooth Pain and Treatment Options When do baby molars come in? Your baby's first molars will probably begin to come in between 13 and 19 months old. The last set of baby molars may finish coming in around 25 to 33 months old. These later fall out to make way for adult molars. When do kids lose their molars? It varies. On average, kids tend to lose their baby molars when they're between 9 and 12 years old. Learn More: When Do Baby Teeth Fall Out? 9 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Cleveland Clinic. Teeth eruption timetable. Ghoncheh Z, Zade BM, Kharazifard MJ. Root morphology of the maxillary first and second molars in an Iranian population using cone beam computed tomography. J Dent (Tehran). 2017;14(3):115-122. Jung YH, Cho BH. Prevalence of missing and impacted third molars in adults aged 25 years and above. Imaging Sci Dent. 2013;43(4):219–225. doi:10.5624/isd.2013.43.4.219 Rakhshan V. Congenitally missing teeth (Hypodontia): A review of the literature concerning the etiology, prevalence, risk factors, patterns and treatment. Dent Res J (Isfahan). 2015;12(1):1-13. doi:10.4103/1735-3327.150286 Jung YH, Cho BH. Prevalence of missing and impacted third molars in adults aged 25 years and above. Imaging Sci Dent. 2013;43(4):219–225. doi:10.5624/isd.2013.43.4.219 Von Cramon-Taubadel N. Global human mandibular variation reflects differences in agricultural and hunter-gatherer subsistence strategies. Proc Natl Acad Sci USA. 2011;108(49):19546-51. doi:10.1073/pnas.1113050108 Fernandes MJ, Ogden GR, Pitts NB, Ogston SA, Ruta DA. Actuarial life-table analysis of lower impacted wisdom teeth in general dental practice. Community Dent Oral Epidemiol. 2010;38(1):58-67. doi:10.1111/j.1600-0528.2009.00501.x Cleveland Clinic. Toothache. American Dental Association. Eruption charts. By Shawn Watson Shawn Watson is an orthodontic dental assistant and writer with over 10 years of experience working in the field of dentistry. See Our Editorial Process Meet Our Medical Expert Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit