The Teeth (Human Anatomy): Diagram, Names, Number, and Conditions Next The teeth are the hardest substances in the human body. Besides being essential for chewing, the teeth play an important role in speech. Parts of the teeth include: • Enamel: The hardest, white outer part of the tooth . Enamel is mostly made of calcium phosphate, a rock-hard mineral. • Dentin: A layer underlying the enamel. Dentin is made of living cells, which secrete a hard mineral substance. • Pulp: The softer, living inner structure of teeth. Blood vessels and nerves run through the pulp of the teeth. • Cementum: A layer of connective tissue that binds the roots of the teeth firmly to the gums and jawbone. • Periodontal ligament: Tissue that helps hold the teeth tightly against the jaw. A normal adult mouth has 32 teeth, which (except for wisdom teeth ) have erupted by about age 13: • Incisors (8 total): The middlemost four teeth on the upper and lower jaws. • Canines (4 total): The pointed teeth just outside the incisors. • Premolars (8 total): Teeth between the canines and molars.

• Molars (8 total): Flat teeth in the rear of the mouth , best at grinding food. • Wisdom teeth or third molars (4 total): These teeth erupt at around age 18, but are often surgically removed to prevent displacement of other teeth. The crown of each tooth projects into the mouth . The root of each tooth descends below the gum line, into the jaw. Teeth Conditions Cavities (caries): Bacteria evade removal by brushing and saliva and damage the enamel and deeper structures of teeth. Most cavities occur on molars and premolars. Tooth decay : A general name for disease of the teeth, including cavities and caries. Periodontitis : Inflammation of the deeper structures of the teeth (periodontal ligament, jawbone, and cementum). Poor oral hygiene is usually to blame. Gingivitis : Inflammation of the surface portion of the gums, around and between the crowns of the teeth. Plaque and tartar buildup can lead to gingivitis . Plaque : A sticky, colorless film made of bacteria and the substances they secrete. Plaque develops quickly on teeth after eating sugary food, but can be easily brushed off.

Tartar : If plaque is not removed, it mixes with minerals to become tartar, a harder substance. Tartar requires professional cleaning for removal. Overbite : The upper teeth protrude significantly over the lower teeth. Underbite : The lower teeth protrude significantly past the upper teeth. Rinsing teeth : Rinsing daily with an antiseptic mouthwash kills bacteria that cause bad breath and gum disease . Teeth cleaning : Professional teeth cleaning every six months may help prevent teeth and gum disease. Tooth filling : Drilling out the diseased part of a tooth and packing the space with a mineral filling can prevent a cavity from destroying the tooth. Root canal : The deep pulp of a tooth is drilled out, cleaned, and filled. A root canal is done when damage to the teeth has affected the deep pulp. Tooth extraction : If a tooth is too damaged to repair with a filling or root canal, it may be removed. Wisdom teeth are often extracted to prevent displacement of the other teeth. Braces : An artificial device or system that places teeth under tension for a long period of time. Eventually, braces can help crooked teeth become realigned.

Mouth guard : A plastic mouthpiece can provide protection from teeth grinding and injury during sports. Dental sealants : A plastic sealant applied to the teeth can help block bacteria from hiding in crevices on teeth surfaces. Sealants can help prevent cavities. Teeth whitening : Over-the-counter and professional chemical treatments can bleach teeth to a brighter white. Tooth sensitivity is the most common side effect. WebMD Image Collection Reviewed by William Blahd, MD on October 22, 2015 Sources Teeth - Anatomy Pictures and Information Home > Skeletal System > Bones of the Head and Neck > Teeth Teeth The teeth are a group of hard organs found in the oral cavity. We use teeth to masticate (or chew) food into tiny pieces. They also provide shape to the mouth and face and are important components in producing speech. A tooth can be divided into two main parts: the crown and root. Found above the gum line, the crown is the enlarged region of the tooth involved in chewing. Like an actual crown, the crown of a tooth has many ridges on its top surface to aid in the chewing of food.

Below the gum line is the region of the tooth called the root, which anchors the tooth into a bony socket known as an alveolus.... Move up/down/left/right: Click compass arrows Rotate image: Click and drag in any direction, anywhere in the frame Identify objects: Click on them in the image 2D Interactive 3D Rotate & Zoom Change Anatomical System Teeth: Dental Plaque and Periodontal Disease Full Teeth Description [Continued from above] . . . Roots are tapered structures resembling the roots of plants, and each tooth may have between one to three roots. The exterior surface of the root is covered in a bone-like mixture of calcium and collagen fibers known as cementum. Cementum provides grip for the periodontal ligaments that anchor the root to the surrounding alveolus. Each tooth is an organ consisting of three layers: the pulp, dentin, and enamel. The pulp of the tooth is a vascular region of soft connective tissues in the middle of the tooth. Tiny blood vessels and nerve fibers enter the pulp through small holes in the tip of the roots to support the hard outer structures.

Stem cells known as odontoblasts form the dentin of the tooth at the edge of the pulp. Surrounding the pulp is the dentin, a tough, mineralized layer of tissue. Dentin is much harder than the pulp due to the presence of collagen fibers and hydroxylapatite, a calcium phosphate mineral that is one of the strongest materials found in nature. The structure of the dentin layer is very porous, allowing nutrients and materials produced in the pulp to spread through the tooth. The enamel – the white, outer layer of the crown – forms an extremely hard, nonporous cap over the dentin. Enamel is the hardest substance in the body and is made almost exclusively of hydroxylapatite. Teeth are classified into four major groups: incisors, canines, premolars, and molars. Incisors are chisel-shaped teeth found in the front of the mouth and have a flat apical surface for cutting food into smaller bits. Canine teeth, also known as cuspids, are sharply pointed, cone-shaped teeth that are used for ripping tough material like meat. They flank the incisors on both sides.

Premolars (bicuspids) and molars are large, flat-surfaced teeth found in the back of the mouth. Peaks and valleys on the flat apical surface of premolars and molars are used for chewing and grinding food into tiny pieces. Babies are born without teeth, but grow a temporary set of twenty deciduous teeth (eight incisors, four canines, and eight molars) between the ages of six months and three years. Baby teeth fill the child’s tiny jaws and allow the child to chew food while larger, stronger adult teeth develop inside the mandible and maxilla bones. At about six years of age the deciduous teeth are slowly shed one at a time and replaced by permanent adult teeth. Adult teeth develop while hidden within the maxilla and mandible after the deciduous teeth have erupted. When an adult tooth erupts, it triggers the roots of the deciduous tooth above it to atrophy. This causes the baby tooth to become loose and eventually fall out. The new permanent tooth slowly pushes up through the gums to replace the baby tooth. Eventually, a total of thirty-two permanent adult teeth form and erupt.

The adult teeth are arranged in both the upper and lower jaws from the midline of the mouth as follows: central incisor, lateral incisor, canine (cuspid), first premolar (bicuspid), second premolar, first molar, second molar, and third molar. The first twenty-eight adult teeth are fully erupted by the age of eleven to thirteen with the third molars, known as wisdom teeth, erupting in the back of the jaw several years later in early adulthood. Sometimes the wisdom teeth become impacted when they grow and become wedged at an abnormal position in the jaws and fail to erupt. In some cases there is not enough room in the jaw to accommodate a third set of molars. In both cases the wisdom teeth are surgically removed, as they are not needed to properly chew food. Mastication, or chewing, is the main function of the teeth. The teeth are aligned in the jaws so that the peaks of one tooth align with the valleys of its counterpart on the other jaw. Every bite forces food into the interface of the teeth to be chopped, while lateral motion of the jaw is used to grind food in the premolars and molars.

Tooth decay and cavities are important health concerns related to the teeth. The enamel that covers the crown in each tooth can be broken down by acids produced by bacteria that live in the mouth and assist in digestion of small bits of food. This process of enamel erosion by acids is called decay. To prevent decay, good oral hygiene, consisting of daily brushing and flossing, is necessary. Decay can eventually lead to cavities, also known as dental caries, where holes appear in the enamel and expose the dentin. Cavities require medical intervention to prevent their growth, usually resulting in the removal of the affected tissue and the filling of the cavity with a hard material to restore the strength and function of the tooth. Prepared by Tim Taylor, Anatomy and Physiology Instructor Wisdom Teeth: Impaction, Removal, Function, and More How Much Does Wisdom Teeth Extraction Cost? Wisdom teeth are the third and final set of molars that most people get in their late teens or early twenties. Sometimes these teeth can be a valuable asset to the mouth when healthy and properly aligned, but more often, they are misaligned and require removal.

When wisdom teeth are misaligned, they may position themselves horizontally, be angled toward or away from the second molars, or be angled inward or outward. Poor alignment of wisdom teeth can crowd or damage adjacent teeth, the jawbone, or nerves. Wisdom teeth also can be impacted -- they are enclosed within the soft tissue and/or the jawbone or only partially break through or erupt through the gum. Partial eruption of the wisdom teeth allows an opening for bacteria to enter around the tooth and cause an infection, which results in pain, swelling, jaw stiffness, and general illness. Partially erupted teeth are also more prone to tooth decay and gum diseas,e because their hard-to-reach location and awkward positioning makes brushing and flossing difficult. How Do I Know if I Have Wisdom Teeth? Ask your dentist about the positioning of your wisdom teeth. He or she may take an X-ray periodically to evaluate for the presence and alignment of your wisdom teeth. Your dentist may also decide to send you to an oral surgeon for further evaluation. Your dentist or oral surgeon may recommend that your wisdom teeth be extracted even before problems develop. This is done to avoid a more painful or more complicated extraction that might have to be done a few years later.

Removal is easier in young people, when the wisdom teeth roots are not yet fully developed and the bone is less dense. In older people, recovery and healing time tend to be longer. How Are Wisdom Teeth Removed? The relative ease at which your dentist or oral surgeon can extract your wisdom teeth depends on their position and stage of development. Your oral health care provider will be able to give you an idea of what to expect during your pre-extraction exam. A wisdom tooth that is fully erupted through the gum can be extracted as easily as any other tooth. However, a wisdom tooth that is underneath the gums and embedded in the jawbone will require an incision into the gums and then removal of the portion of bone that lies over the tooth. Often, for a tooth in this situation, the tooth will be extracted in small sections rather than removed in one piece to minimize the amount of bone that needs to be removed to get the tooth out. Continued What Happens During Wisdom Teeth Removal? Before your wisdom teeth are pulled, the teeth and the surrounding tissue will be numbed with a local anesthetic -- the same type used to numb a tooth prior to having a cavity filled.

In addition to the local anesthetic to numb the pain, you and your dentist or oral surgeon may decide that a sedative is desired to control any anxiety . Sedating medications that could be selected include: nitrous oxide (otherwise known as "laughing gas"), an oral sedative (for example, Valium ), or an intravenous sedative (administered via an injection into your veins). If nitrous oxide is given, you will be able to drive yourself home. If any of the other medications is selected, you will need someone to drive you both to and from the appointment. What Does Recovery Involve After Wisdom Teeth Are Pulled? After having your wisdom teeth removed, the speed of your recovery depends on the degree of difficulty of the extraction (a simple extraction of a fully erupted tooth versus a tooth impacted into the jawbone). In general, here's what to expect. During the first 24 hours Bleeding may occur for several hours after tooth extraction . To control it, position a piece of clean moist gauze over the empty tooth socket and bite down firmly. Apply constant pressure for about 45 minutes. A moistened tea bag is an effective alternative.

The tannic acid in tea helps healing blood clots to form (blood clots function similarly to scab over an open wound). Repeat this process if a small degree of bleeding continues; if heavy bleeding continues to occur, contact your dentist or oral surgeon. Avoid rinsing or spitting for 24 hours after tooth extraction, avoid "sucking" actions (for example, don't drink beverages through straws or smoke) and avoid hot liquids (such as coffee or soup). These activities can dislodge the clot, causing a dry socket (see below) to develop. Facial swelling in the area where the tooth was extracted typically occurs. To minimize swelling, place a piece of ice, wrapped in a cloth, on that area of your face on a schedule of 10 minutes on, followed by 20 minutes off. Repeat as necessary during this first 24-hour period. Pain medications, such as acetaminophen ( Tylenol ) or ibuprofen ( Motrin or Advil ), can be taken for minor pain. Your dentist or oral surgeon may prescribe more potent pain relievers, if necessary.

Antibiotics that may have been prescribed prior to tooth extraction (to treat any active infection around the wisdom tooth to be extracted) should continue to be taken until the full prescription is gone. Foods should be restricted to a liquid diet until all the numbness from anesthesia has worn off. Eat soft foods for a few days. Also avoid alcohol if you're also taking narcotic pain medication. Continue to brush your teeth, but avoid the teeth directly neighboring the extracted tooth during the first 24 hours. On day two, resume the gentle brushing of your teeth. Do not use commercial mouth rinses -- these can irritate the extraction site. Continued After 24 hours Facial swelling in the area of the tooth extraction should be treated with heat after the first 24 hours of ice. Apply a moist warm towel to the area on a 20-minute on, 20-minute off schedule. Repeat as necessary. Rinse your mouth with warm salt water (1/2 teaspoon of salt in a cup of warm water) after meals and before bed. Do not use commercial mouth rinses.

Stitches , if used and if not of the self-dissolving type, need to be removed by your oral health care provider in about 1 week. If you do require stitches, ask what type you have been given. Watch for signs of dry socket (described below). This condition requires treatment by your oral health care provider. Complete healing doesn't occur for a few weeks to a few months following the extraction. However, usually within the first week or two, enough healing has taken place for use of your mouth to be reasonably comfortable in the area of the extraction. Your dentist will explain what to expect in your specific case. What Are Potential Complications of Wisdom Tooth Removal? Two of the more important complications after having your wisdom teeth removed include: Dry socket. Dry socket is a common complication that occurs when either a blood clot has failed to form in the extracted tooth socket or else the blood clot that did form has been dislodged. Without clot formation, healing will be delayed. When it happens, dry socket typically occurs 3 or 4 days following the extraction and is accompanied by pain (ranging from "dull" to moderate to severe) and a foul mouth odor.

Your dentist or oral surgeon will treat the dry socket by placing medication in the socket. Paresthesia. Paresthesia is a rarer complication of wisdom teeth extraction. Wisdom teeth entrapped in the jawbone are often close to nerves. Sometimes these nerves can be bruised or damaged during the tooth removal process. The result is a numbness (called a paresthesia) of the tongue , lip, or chin that can last a few days, weeks, months, or may even be permanent. Continued How Much Does Wisdom Teeth Extraction Cost? Simple extraction of a wisdom tooth can cost as little as $99 per tooth. The cost of wisdom teeth that are impacted can cost between $230 and $340 and even more. Because costs vary in different areas of the country, contact your dentist or oral surgeon for their charges. Also, check with both your dental insurance carrier and medical insurance provider. One or the other type of insurance may cover a portion of the cost of wisdom teeth removal. Teeth Names & Numbers How are teeth named and numbered? Teeth Names & Numbers Dentists refer to a specific tooth using a number or coding more usually than using teeth names.

There are several teeth numbering systems: the Universal Numbering System (used in US), FDI World Dental Federation notation, and the Palmer Notation Method. However, for patients it is easier to identify and remember the different teeth by using more descriptive teeth names instead of numbers or other coding. Universal tooth numbering system The Universal Numbering System is a simplified method of identifying teeth that is approved and adopted by the American Dental Association. Adults In the universal tooth numbering system, tooth number 1 is the patient's upper right third molar, on the right side of the mouth in the upper (maxillary) jaw. Numbering of teeth continues along the upper teeth toward the front and across to the last molar tooth back on the top left side (number 16). The tooth numbering continues by assigning teeth numbers descending to the lower left third molar (number 17) and follows the lower (mandibular) jaw up to the tooth farthest back on the bottom right side of the mouth (number 32). All teeth that should be there are numbered, including those teeth that have been removed for any reason or have not erupted yet (e.g. wisdom teeth).

Children In the original system, children's 20 primary teeth are numbered in the same order (from 1 to 20), except that a small letter "d" follows each number to indicate deciduous (primary) teeth. However, most dentists today use a modified version of the Universal Numbering System for children, with letters instead of teeth numbers. The primary teeth are designated by upper case letters A through T, with A being the patient's upper right second primary molar and T being the lower right second primary molar. Universal tooth numbering system Third Molars There are many good reasons for removing wisdom teeth also known as third molars, there are also some risks and complications that are possible when extracting these teeth and sometimes there are some good reasons for leaving them alone. The decision on a specific course of action must be determined by a well informed doctor and patient working together. Consider first the many reasons that people choose to have their third molars extracted. By far one of the most common findings is that the mouth is just too small for these teeth to fully erupt into a good functional position. This leads to one of several situations. 1.

The teeth remain completely buried in the bone of the upper and lower jaws in which they developed, a condition known as impaction. In the case of the fully impacted tooth, it may continue to sit in the bone, surrounded by the normal cyst in which all teeth develop. It may also happen that the normal cyst, later in life, enlarges and may even develop changes in the cells that line the cyst. When such cysts get large enough, they should be removed and examined by a pathologist. 2. The teeth begin to erupt but are not able to assume their correct upright position. Most commonly the upper third molars will tend to face out towards the cheeks while the lower third molars will lean forward with just a small portion of the crown protruding through the gum. Teeth that are partially erupted lead to two problems. A) First they make hygiene of the second molars difficult leading to increased possiblity of decay and gum disease (periodontal disease) around these important teeth.

B) Second the pink flap of gum tissue which partially covers the erupting tooth creates a warm, moist and dark pocket where bacteria which normally live in the mouth can use the food you eat to flourish, multiply and cause an infection known as pericoronitis. In fortunate cases, the swelling and pain of this condition will be relieved when the infection drains back into the mouth. In those less fortunate, the swelling persists, does not drain back into the mouth but rather extends laterally and if not treated can become a very serious infection. The treatment of choice for pericoronitis is extraction of the offending tooth. Antibiotics, operculectomies and other adjuncitve treatments may be helpful from time to time but the problem has a propensity to return as long as the conditions which allowed it to develop in the first place continue to exist. It is easy to understand why many people choose to hedge their bets and have their wisdom teeth extracted while they are young and healthy and the teeth are surrounded only by a small normal developmental cyst rather than have to undergo a more extensive surgical procedure later in life when their recovery may not be as easy and their general state of health may not be as good.

Finally, some dentists subscribe to the theory that wisdom teeth may push the other teeth in the mouth forward and cause crowding and misalignment. You should be aware however, that not all oral surgeons believe this to be the case. Now however, it is important to consider the possible risks and complications involved in the removal of third molars. There are some risks/potential complications which are common to all surgical procedures however major or minor they might be. These are: PAIN Removal of third molars is a surgical procedure and some discomfort should be expected. It is also reasonable to expect that this discomfort will be taken care of by the pain medication prescribed. INFECTION In the absence of preexisting infection it is uncommon to see an infection resulting from the removal of third molars however, there are more bacteria per square inch in the oral cavity than anywhere else in the human body and so often patients are placed on antibiotics prophylactically during the initial healing period. SWELLING Post operative swelling and bruising are both within the spectrum of normal. The exact amount of each of these varies from patient to patient as does the time required for complete resolution of these symptoms. Surgical edema is a normal consequence of surgery and also normally resolves without extraordinary measures.

BLEEDING It is not possible to do surgery without some bleeding but when you leave your surgeon's office you should expect that the minimal oozing you are experiencing can be easily controlled by biting on clean gauze or a tea bag. Bleeding that cannot be controlled in such a fashion warrants an immediate call to the surgeon. and the risk of the ANESTHETIC itself. Most wisdom teeth COULD be removed without any anesthesia at all...but that would make for a very unhappy patient and an equally unhappy doctor. For patients whose medical condition contraindicates general anesthesia, third molars can safely and effectively be removed with local anesthetic only. Local anesthestics as used in the oral surgeon's office are among the safest of drugs around and true allergic reaction to a properly administered local anesthetic is so rare as to be worthy of publication in scientific journals. Most persons prefer, however, to be "asleep" for the removal of their third molars. There is a somewhat greater risk for this than for the use of local anesthetic alone and if this is your desire, your oral surgeon should discuss your medical history and your particular risks with you prior to your procedure.

You should be aware that in the young healthy individual, those risks are often minimal and acceptable but they do exist and should be discussed with the doctor. Finally there are some risks/complications that are unique to the removal of third molars. The upper third molars have roots which often are separated from the maxillary sinuses by only a very thin layer of bone. Occasionally, a small communication is established between the sinus and the oral cavity when one of the upper third molars is removed. If this is the case, the normal procedure is for the area to be sutured closed, the patient to be informed of the finding, appropriate antibiotics and decongestants to be prescribed, the patient to be instructed to avoid Valsalva maneuvers (tasks which build up pressure in the sinus like nose blowing and bearing down forcefully) and the patient reappointed for followup. Most often this results in an uneventful healing period with no further treatment being required. Occasionally, the area will heal open rather than closed in which case an additional small surgical procedure will be required to close the communication. The lower third molars often have roots that lie very near or even wrapped around the inferior alveolar nerve.

This is the nerve that supplies feeling to the lip, teeth and part of the gums on each side of the mouth. Occasionally, when a lower third molar is removed, that nerve will be bumped or bruised and if so a change in sensation may be noted on that side. It is important to understand that this is a sensory nerve and does not affect the ability to move the parts of the oral cavity to which it gives sensation (feeling). In most cases, the nerve heals itself but, because nerves heal slowly, it may take six months to one year before return of normal sensation. Very rarely, the damage to the nerve is permanent. Likewise, the lingual nerve, which supplies sensation to the tongue and the tongue side of the gums often lies in close proximity to the surgical site and may be disturbed in the process of removing these lower third molars. Once again, most alterations in sensation are temporary but ocasionally the change may be permanent. Finally, the normal precautions, risks and benefits of extraction of any tooth (which are beyond the scope of this discussion) also apply here and should be discussed with the surgeon prior to beginning any procedure.

Types of Teeth - Human Teeth Types of Teeth - Human Teeth The 4 Types of Human Teeth Humans, same as the rest of the mammals, are heterodont animals, meaning that they have several different forms of teeth. Human teeth differentiate in shape, while more primitive animals are homodont and all their teeth have the same shape possibly differing only on size. Permanent human teeth come in four different types: incisors , canines , premolars , and molars . Types of teeth Human teeth belong to four distinct types each having a typical appearance and performing a certain function. The shape and morphology of each human tooth type depends on the function that it is assigned to perform. As a species, humans are omnivorous eating both meats and plants, so they need different types of teeth to handle both types of food. Generally, carnivorous animals need sharp teeth to pierce and tear meat, while herbivorous animals need flat teeth to crush and grind plants. Humans, as omnivorous, must have at least these 2 types of teeth. Through evolution humans have developed 4 different main teeth types: 1. Incisors Incisors (Cutting teeth) are the teeth at the center of the dental arch.

There are eight incisors in total in the permanent (and primary) dentition, two on either side (left and right) in the upper and lower jaw. The middle four of them (one at each quadrant) are called central incisors, while the other four next to them are named lateral incisors. Incisors are flat and board, shaped like a shovel with a narrow straight cutting edge that enables them to cut food. The main functions of an incisor in the mastication process are biting, cutting of food into chewable pieces and moving it inwards the mouth. All eight incisors have a single root and almost the same shape, but their size may differ slightly with the upper incisors usually larger, and especially the central ones. 2. Canines (cuspids) Canines (also called eye teeth or cuspids) are the teeth located next to the incisors towards the edge of the mouth. There are 4 canines in both primary and permanent human dentitions, one at each quadrant of the mouth. They are the third teeth from the center. They have a sharp pointed edge that is used to rip and tear tough foods such as meat.

In humans canine teeth have the same height as the rest of the teeth but in other animals they are longer and used to bite and kill prey. Canines have a single but long root that can reach up to 3 cm providing the stability required for their function. They are the longest and most stable human teeth. 3. Premolars (bicuspids) Premolars (also called bicuspids) are the teeth located after the canines towards the back of the mouth. There are eight premolars in the permanent dentition, two on either side (left and right) in the upper and lower jaw. The front four of them (one at each quadrant) are called first premolars, while the other four on the back are called second premolars. The premolars are the fourth and fifth teeth from the midline. Premolars are only present in the permanent dentition; there are no premolars in the primary human dentition. When they erupt, they replace the primary molars. The morphology of premolars is a combination between canines and molars. They are also known as bicuspids, because usually they have at least two cusps on their upper side.

Premolars have a broader surface for chewing and grinding, but they also have some sharp points for piercing and ripping at the edge of the cusps. Their major role is to begin the crushing of foods before they are transferred to the molars for the final grinding. The upper jaw first premolars have two roots, while the upper second ones and all the lower jaw premolars have only one root. 4. Molars Molars are the teeth located at the back of the dental arch. Adult humans have twelve molars, three on either side (left and right) in the upper and lower jaw. There are only 8 molars in the primary dentition which are replaced by the permanent premolars. Permanent molars are named as first, second, and third starting from the front to the back. The third molars are also known as wisdom teeth. Wisdom teeth are the last teeth to erupt behind all other teeth at the age of 17-25 years, much later than the rest. The molars are the sixth, seventh, and eighth teeth from the midline. Molars perform most of the chewing, by crushing and finalizing grinding before swallowing the food.

The first and second molars have a similar shape with premolars, but they are larger (with the first molar larger than the second one). The mandibular first molars (the one at the lower jaw) are usually the largest teeth of the human mouth. They have a more flattened surface with four to five cusps, and two to three roots. The morphology and size of third molars (wisdom teeth) may vary significantly but they are usually smaller than the other molars. In some cases they fail to erupt properly in the mouth, either remaining trapped inside the jaw bone (impacted wisdom teeth), or erupting partially causing a painful condition known as pericoronitis . The Evolution of Wisdom Teeth - Are people without wisdom teeth more highly evolved? | HowStuffWorks Are people without wisdom teeth more highly evolved? Track the progress of the jaw in this illustration of human evolution. Doring Kindersley/Getty Images There was a time when our jaws could comfortably accommodate all 32 teeth, including the third molars. You have to go back about 100 million years ago, though, to the prehistoric version of man.

Instead of walking upright, this guy got around on all four limbs, with a massive protruding jaw leading the way. Early man's jaws were larger and more prominent because teeth played a vital role in survival. With the front appendages occupied with balance and running, teeth were prehistoric man's means of catching, dismembering and consuming prey. Our ancestors subsisted on a tough and chewy diet of leaves, roots and raw meat. Having 32 teeth's worth of chewing ability was a huge advantage at this point, especially because early man didn't visit the dentist with the regularity we do today; third molars might have played an important backup role when teeth were lost or worn down. Up Next How Kin Selection Works Then evolution had its way with prehistoric man, and teeth weren't so important anymore. Hominids began walking upright, and arms took on a greater role in obtaining food . After that, brains became larger and jaws became shorter. Researchers still aren't exactly certain which came first, though in 2004, a team from the University of Pennsylvania announced they had discovered a gene called MYH16.

Mutations in this gene lead to shorter jaws, which may have been the factor which allowed early man's brain to grow [source: Wilford ]. However it happened, the change lessened the amount of space available to teeth in the mouth. As our heads and jaws were changing, some cultural shifts were taking place as well. Around the same time, man was creating the first tools, including cooking utensils (designed, of course, by primitive prototypes of Food Network hosts). With bigger brains, man got wise to fire and its ability to soften food. Overall, man's diet became much more processed; compared to the roots and raw meat our ancestors ate, we might as well be eating strained applesauce. In fact, we wouldn't necessarily need any teeth at all to survive today, though dining out would be a dull affair. As it is, though, we definitely decreased our reliance upon the third molar. Opponents of evolution place greater weight on the dietary shift and dental hygiene in lessening our reliance on wisdom teeth, discounting the role of our evolving jaws and brains. But when you line up a prehistoric jaw and a modern jaw, the space is clearly smaller. Can evolution explain the shift?

And if our evolutionary history has lessened the need for wisdom teeth and created conditions inhospitable to third molars, will we ever lose them completely? Wisdom Teeth Removal, Pain, Recovery Time & Impacted Teeth Medical Author: Steven B. Horne, DDS Steven B. Horne, DDS Dr. Steve Horne began his career at Brigham Young University obtaining his BA in English. He earned his Doctorate of Dental Surgery in 2007 from the University of Southern California where his pursuit for academic excellence landed him on the Dean's List. He was recognized for his superior clinical skills and invited to help teach other dental students in courses on restorative dentistry, prosthodontics, and tooth anatomy. During dental school, he provided dental care for underserved populations of Los Angeles and Orange County, Mexico, and Costa Rica with AYUDA. Following dental school, Dr. Horne entered active duty with the U.S. Army and practiced dentistry at Fort Knox, Kentucky, for four years. During this time, he was deployed to Baghdad, Iraq, and received multiple Army Achievement Medals, the Army Commendation Medal, and served as Company Commander. Dr.

Horne currently practices full time at Torrey Pines Dental Arts in La Jolla, California, as a general dentist. Dr. Horne is a member of the American Dental Association, the California Dental Association, and the Academy of General Dentistry. Dr. Horne is married to his wife, Christy, and they have a chocolate Labrador named Roscoe. Medical Editor: Charles Patrick Davis, MD, PhD Charles Patrick Davis, MD, PhD Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications. Click to see a picture of wisdom teeth » What are wisdom teeth? Wisdom tooth is another name for any one of four third molars found in the permanent dentition (adult teeth ). These teeth are the last or most posterior teeth in the dental arch.

Although most people have wisdom teeth , it is possible for some or all of the third molars to never develop. It is also possible for a person to have more than four wisdom teeth. In many individuals, the wisdom teeth aren't visible because they have become impacted (not normally erupted through the gums) under the gingival tissue. How do I know if I have wisdom teeth? You know if you have wisdom teeth by examining your mouth and finding three permanent molars in each dental quadrant. However, if the tooth is impacted under the tissue, presence of the tooth needs to be verified by a radiograph. A panoramic radiograph is usually the preferred X-ray to help assess the angle of eruption and state of development of the tooth. Most wisdom teeth can be visualized erupting through the gingiva in early adulthood, between the ages of 16 to 23. Sometimes, a person will feel the effects of the wisdom teeth before they are able to visualize them in their mouth. Erupting wisdom teeth will usually produce a feeling of pressure or dull throbbing in the back of the jaws. Your general dentist will often be able to inform you of the condition of these erupting teeth. Do all wisdom teeth need to be extracted?

Share Your Story Not all wisdom teeth need to be extracted. When a wisdom tooth erupts cleanly through the tissue without compromising the adjacent tooth, the wisdom tooth can be retained in the mouth with little concern as long as the person is able to brush, floss, and clean it thoroughly. The condition of the wisdom teeth changes a lot between the ages of 16 and 23; it is imperative that wisdom teeth are examined regularly by a dental professional to determine the proper diagnosis and course of action in this age group. Sometimes the wisdom teeth cause pain , but a person can avoid extracting them with a few modifications of the surrounding tissues or oral hygiene habits. If there is a small flap of swollen gum tissue barely covering the back of the tooth, a person may have pain from biting down on that gum tissue. If there is otherwise enough room for the wisdom tooth, the gum tissue can be removed from the back of the tooth to remedy this problem. Changing the angle of tooth brushing and increasing the frequency of flossing both in front and behind the wisdom teeth can help keep the gum tissues healthy and avoid the potential of painful gingivitis or infection around the wisdom teeth. There are certain situations, however, where extraction of wisdom teeth is absolutely necessary.

The wisdom tooth may erupt at an angle such that the adjacent molar can become difficult to keep clean and free of dental caries . Sometimes the position of the wisdom tooth will cause deep periodontal pockets, gum disease or recession around the adjacent tooth, and should be removed before too much damage is caused to the much more critical second molars. If there isn’t sufficient room in the mouth for the wisdom teeth and they are trying to erupt, they may cause significant pressure on the surrounding teeth and tissues. This pressure can result in a bad headache , jaw pain /stiffness or tooth pain that is only resolved by removing the wisdom teeth. The pressure can give the impression that the wisdom teeth are causing crowded teeth. If the third molar has erupted through the tissue but is without opposing occlusion (contact with other teeth), extraction should still be considered. Considering the posterior position of an erupted wisdom tooth, these teeth are often difficult to keep clean. If wisdom teeth get tooth decay , it is usually best to extract them instead of removing the decay and fixing wisdom teeth with fillings , root canals, or crowns.

These treatments that are indicated for the rest of the teeth, are often less successful in treating wisdom teeth due to their position in the back of the mouth. Removal of a wisdom tooth is indicated if the tooth has partially erupted through the gingival tissue, causing inflammation and/or infection. This condition is called a partially erupted, or partially impacted wisdom tooth. A soft-tissue growth over a partially erupted wisdom tooth is referred to as an operculum. If bacteria become trapped under the operculum, an infection called pericoronitis can develop. Medically Reviewed by a Doctor on 5/26/2016 Human Teeth Dental Chart - Bradford Dentistry Resources | Bradford Family Dentistry See Cat Teeth See Horse Teeth At the time of birth, tooth buds are already in place. Babies typically have 20 primary (baby) teeth, which usually begin to erupt typically around 6 months of age but can be anywhere between approximately 3 months of age until 12 months to begin the accommodation of solid foods and the change in baby’s diet. The above human teeth dental chart are of children’s 20 primary teeth. Cutting teeth takes time and can be painful for babies, which is usually completed by the age of 3.

Teeth start to fall out at various times throughout childhood and by the age of 21; all 32 of the permanent teeth have usually erupted. Eruption of Primary Teeth Dental Chart Usually, humans get two sets of teeth during a lifetime. The first, primary or deciduous set is comprised of the 20 “baby” teeth. The second permanent set usually consists of 32 teeth. In each quadrant, there are eight permanent teeth including two incisors, one cuspid, two bicuspids, and three molars. Eruption of Permanent Teeth Dental Chart The pictorial below of permanent human teeth can help you to understand the positioning of each of your 32 permanent teeth in an adult mouth. The last teeth to arrive are the three molars. The third molars are more commonly referred to as the “wisdom tooth.” Tooth Chart Positioning The upper teeth of arch on the human teeth dental chart are called maxillary teeth because their roots are placed within the upper jawbone of the maxilla. Those of the lower arch are called mandibular teeth because their roots are embedded within the lower jawbone of the mandible.

Each arch contains 16 teeth, composed of 6 anterior, and 10 posterior and in a quadrant, there are 3 anterior and 5 posterior teeth. On this human teeth diagram, there are four classes of teeth, incisors, cuspid, bicuspid and molars, based on appearance, position and complementary functions. A tooth is a hard, bony appendage that develops on the jaw to pulverize food. In man, the design of the teeth is a reflection of eating habits, as humans tend to be meat eaters so teeth are formed for cutting, tearing, and grinding food. The human teeth dental chart illustrates the types and working surfaces of the four classes of teeth. Incisor Teeth On the dental chart, incisors are located in the front of the mouth and have sharp, thin edges for cutting. Their use is to incise or cut food and the appearance tends to have a shovel-shaped appearance. Cuspid Teeth Cuspids, also referred to as canines, are at the angles of the mouth on the tooth chart. Each has a single cusp and is designed for cutting and tearing. Bicuspid Teeth Bicuspids, also referred to as premolars, are similar to the cuspids.

They have two cusps used for cutting and tearing, and a wider surface to bite and crush food. Molars Molars are located in the back of the mouth. Their size gradually gets smaller from the first to third molar. Each molar has four or five cusps, is shorter and more rounded in shape than other teeth and has a broad surface for grinding and chewing solid food. When viewing the human teeth dental chart, it shows the typical human mouth. People are all different and do not always have every tooth come in or they may appear at different times. When extractions or exclusions occur, depending on the tooth, different methods can get chewing accomplished. Although your teeth may not be identical to the human teeth dental chart, we can create a smile you can be confident and proud of, while meeting the functions required. Please contact us to discuss any issues concerns or maintenance you may need addressed. If you live in any of the following areas and would like to book an appointment to see your human teeth dental chart for free, please call us at: 1-877-283-0497 in:

Question: In the human body what is the common name for the third molar teeth?
Answer: Wisdom Teeth