The buccinator is a thin quadrilateral muscle occupying the interval between the maxilla and the mandible at the side of the face. It forms the anterior part of the cheek or the lateral wall of the oral cavity.
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. They have at least two cusps. Premolars can be considered transitional teeth during chewing, or mastication. They have properties of both the canines, that lie anterior and molars that lie posterior, and so food can be transferred from the canines to the premolars and finally to the molars for grinding, instead of directly from the canines to the molars.
In orthodontics, a malocclusion is a misalignment or incorrect relation between the teeth of the upper and lower dental arches when they approach each other as the jaws close. The English-language term dates from 1864; Edward Angle (1855–1930), the "father of modern orthodontics", popularised it. The word derives from mal- 'incorrect' and occlusion 'the manner in which opposing teeth meet'.
The mandibular second premolar is the tooth located distally from both the mandibular first premolars of the mouth but mesial from both mandibular first molars. The function of this premolar is assist the mandibular first molar during mastication, commonly known as chewing. Mandibular second premolars have three cusps. There is one large cusp on the buccal side of the tooth. The lingual cusps are well developed and functional. Therefore, whereas the mandibular first premolar resembles a small canine, the mandibular second premolar is more alike to the first molar. There are no deciduous (baby) mandibular premolars. Instead, the teeth that precede the permanent mandibular premolars are the deciduous mandibular molars.
The mandibular first molar or six-year molar is the tooth located distally from both the mandibular second premolars of the mouth but mesial from both mandibular second molars. It is located on the mandibular (lower) arch of the mouth, and generally opposes the maxillary (upper) first molars and the maxillary 2nd premolar in normal class I occlusion. The function of this molar is similar to that of all molars in regard to grinding being the principal action during mastication, commonly known as chewing. There are usually five well-developed cusps on mandibular first molars: two on the buccal, two lingual, and one distal. The shape of the developmental and supplementary grooves, on the occlusal surface, are described as being M-shaped. There are great differences between the deciduous (baby) mandibular molars and those of the permanent mandibular molars, even though their function are similar. The permanent mandibular molars are not considered to have any teeth that precede it. Despite being named molars, the deciduous molars are followed by permanent premolars.
Dens evaginatus is a rare odontogenic developmental anomaly that is found in teeth where the outer surface appears to form an extra bump or cusp.
Dental anatomy is a field of anatomy dedicated to the study of human tooth structures. The development, appearance, and classification of teeth fall within its purview. Tooth formation begins before birth, and the teeth's eventual morphology is dictated during this time. Dental anatomy is also a taxonomical science: it is concerned with the naming of teeth and the structures of which they are made, this information serving a practical purpose in dental treatment.
Edward Hartley Angle was an American dentist, widely regarded as "the father of American orthodontics". He was trained as a dentist, but made orthodontics his speciality and dedicated his life to standardizing the teaching and practice of orthodontics. He founded the Angle School of Orthodontia in 1899 in St. Louis and schools in other regions of the United States. As the originator of the profession, Angle founded three orthodontic schools between 1905 and 1928 in St. Louis, Missouri, New London, Connecticut and Pasadena, California. These exclusive institutions provided the opportunity for several pioneering American orthodontists to receive their training.
Occlusion, in a dental context, means simply the contact between teeth. More technically, it is the relationship between the maxillary (upper) and mandibular (lower) teeth when they approach each other, as occurs during chewing or at rest.
A cusp is a pointed, projecting, or elevated feature. In animals, it is usually used to refer to raised points on the crowns of teeth. The concept is also used with regard to the leaflets of the four heart valves. The mitral valve, which has two cusps, is also known as the bicuspid valve, and the tricuspid valve has three cusps.
This is a list of definitions of commonly used terms of location and direction in dentistry. This set of terms provides orientation within the oral cavity, much as anatomical terms of location provide orientation throughout the body.
In dentistry, crossbite is a form of malocclusion where a tooth has a more buccal or lingual position than its corresponding antagonist tooth in the upper or lower dental arch. In other words, crossbite is a lateral misalignment of the dental arches.
Overbite is the extent of vertical (superior-inferior) overlap of the maxillary central incisors over the mandibular central incisors, measured relative to the incisal ridges.
Serial extraction is the planned extraction of certain deciduous teeth and specific permanent teeth in an orderly sequence and predetermined pattern to guide the erupting permanent teeth into a more favorable position.
The curve of Wilson is the across arch curvature or posterior occlusal plane. Arc of the curve, which is concave for mandibular teeth and convex for maxillary teeth are defined by a line drawn from left mandibular first molar to right mandibular first molar.
Charles Henry Tweed was an American orthodontist known for many of his contributions to the field of orthodontics. He was a founder of the Charles H. Tweed Foundation for Orthodontic Research. Tweed a student of Edward Angle in Pasadena, California and a classmate of Raymond Begg.
Intrusion is a movement in the field of orthodontics where a tooth is moved partially into the bone. Intrusion is done in orthodontics to correct an anterior deep bite or in some cases intrusion of the over-erupted posterior teeth with no opposing tooth. Intrusion can be done in many ways and consists of many different types. Intrusion, in orthodontic history, was initially defined as problematic in early 1900s and was known to cause periodontal effects such as root resorption and recession. However, in mid 1950s successful intrusion with light continuous forces was demonstrated. Charles J. Burstone defined intrusion to be "the apical movement of the geometric center of the root (centroid) in respect to the occlusal plane or plane based on the long axis of tooth".
Orthodontic indices are one of the tools that are available for orthodontists to grade and assess malocclusion. Orthodontic indices can be useful for an epidemiologist to analyse prevalence and severity of malocclusion in any population.
Occlusion according to The Glossary of Prosthodontic Terms Ninth Edition is defined as "the static relationship between the incising or masticating surfaces of the maxillary or mandibular teeth or tooth analogues".
Lonchocyon is an extinct genus of arctoid carnivorans, with possible affinities to amphicyonids or hemicyonine bears. It contains a single species, Lonchocyon qiui, known from a single left mandible discovered at the fossil-bearing locality Haerhada at the base of the Baron Sog Formation, which is located in Inner Mongolia, China, and dates to the late Eocene. This taxon is notable for its large size in comparison to other arctoid carnivorans of the Eocene epoch, and for its hypercarnivorous adaptions, most notably its large canine and strongly reduced premolars. The genus name is a combination of Greek lonch, meaning spear and referencing the spear-like paraconid on its lower carnassial, and cyon, meaning dog. The specific name honours Professor Zhan-Xiang Qiu.
