The maxillary first premolar is one of two

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

located in the upper jaw, laterally (away from the midline of the

face The face is the front of an animal's head that features the eyes, nose and mouth, and through which animals express many of their emotions. The face is crucial for human identity, and damage such as scarring or developmental deformities may aff ...

) from both the

maxillary canine In human dentistry, the maxillary canine is the tooth located laterally (away from the midline of the face) from both maxillary lateral incisors of the mouth but mesial (toward the midline of the face) from both maxillary first premolars. Both the ...

s of the

mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on ...

but mesial (toward the midline of the face) from both

maxillary second premolar The maxillary second premolar is one of two teeth located in the upper maxilar, laterally (away from the midline of the face) from both the maxillary first premolars of the mouth but mesial (toward the midline of the face) from both maxillary first ...

s. The function of this

premolar The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mouth ...

is similar to that of canines in regard to tearing being the principal action during

mastication Chewing or mastication is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow a more efficient break down by enzymes. During the mastication process, th ...

, commonly known as chewing. There are two

cusp A cusp is the most pointed end of a curve. It often refers to cusp (anatomy), a pointed structure on a tooth. Cusp or CUSP may also refer to: Mathematics * Cusp (singularity), a singular point of a curve * Cusp catastrophe, a branch of bifurca ...

s on maxillary first premolars, and the buccal (closest to the cheek) cusp is sharp enough to resemble the

prehensile Prehensility is the quality of an appendage or organ (anatomy), organ that has Adaptation (biology), adapted for grasping or holding. The word is derived from the Latin term ''prehendere'', meaning "to grasp". The ability to grasp is likely der ...

teeth found in carnivorous animals. There are no deciduous maxillary premolars. Around 10-11 years of age, the primary molars are shed and the permanent premolars erupt in their place. It takes about 3 years for the adult premolar and its root to fully calcify. Due to its long buccal root with narrow root canal and short palatal root with wide root canal, the upper 1st premolar is very prone to fracture during exodontia, hence, it is sometimes referred to some dentists as the "King of Fracture". In the

universal system of notation The Universal Numbering System, sometimes called the "American System", is a dental notation system commonly used in the United States. Most of the rest of the world uses the FDI World Dental Federation notation, accepted as an international sta ...

, the permanent maxillary premolars are designated by a number. The right permanent maxillary first premolar is known as "5", and the left one is known as "12". In the

Palmer notation Palmer notation (sometimes called the "Military System" and named for 19th-century American dentist Dr. Corydon Palmer from Warren, Ohio) is a dental notation (tooth numbering system). Despite the adoption of the FDI World Dental Federation notati ...

, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right first premolars would have the same number, "4", but the right one would have the symbol, "┘", underneath it, while the left one would have, "└". The international notation has a different numbering system than the previous two, and the right permanent maxillary first premolar is known as "14", and the left one is known as "24".

References

*Ash, Major M. and Stanley J. Nelson, 2003. ''Wheeler’s Dental Anatomy, Physiology, and Occlusion.'' 8th edition. Types of teeth Human mouth anatomy {{dentistry-stub