The Lewis offset is a term for the portion of the central groove on a permanent mandibular first molar which lies between the two central pits. It was named for long time dental anatomy instructor Dr. Christopher S. Lewis, a Mercer Island, WA dentist.
The offset lies at an angle to the mesio-distal axis of the tooth, and causes the mesial portion of the central groove to be located further buccally than the distal portion. This buccolingual shift correlates with a relative difference in size between the mesial and distal cusps on these teeth - the mesiolingual cusp is larger than the mesiobuccal cusp, but the distobuccal cusp is larger than the distolingual cusp. It also allows for the buccal groove to be located mesial to the lingual groove which is mandatory to accommodate the relative sizes of the three cusps on the buccal and two cusps on the lingual of the occlusal surface of the tooth.
In mammalian oral anatomy, the canine teeth, also called cuspids, dog teeth, or fangs, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed teeth. They can appear more flattened however, causing them to resemble incisors and leading them to be called incisiform. They developed and are used primarily for firmly holding food in order to tear it apart, and occasionally as weapons. They are often the largest teeth in a mammal's mouth. Individuals of most species that develop them normally have four, two in the upper jaw and two in the lower, separated within each jaw by incisors; humans and dogs are examples. In most species, canines are the anterior-most teeth in the maxillary bone.
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.
Dorudon ("spear-tooth") is a genus of extinct basilosaurid ancient whales that lived alongside Basilosaurus 40.4 to 33.9 million years ago in the Eocene. They were about 5 m (16 ft) long and fed on small fish and mollusks. Dorudon lived in warm seas around the world. Fossils have been found along the former shorelines of the Tethys Sea in present-day Egypt and Pakistan, as well as in the United States, New Zealand, and Western Sahara.
The maxillary central incisor is a human tooth in the front upper jaw, or maxilla, and is usually the most visible of all teeth in the mouth. It is located mesial to the maxillary lateral incisor. As with all incisors, their function is for shearing or cutting food during mastication (chewing). There is typically a single cusp on each tooth, called an incisal ridge or incisal edge. Formation of these teeth begins at 14 weeks in utero for the deciduous (baby) set and 3–4 months of age for the permanent set.
The maxillary lateral incisors are a pair of upper (maxillary) teeth that are located laterally from both maxillary central incisors of the mouth and medially from both maxillary canines. As with all incisors, their function is for shearing or cutting food during mastication, commonly known as chewing. There are generally no cusps on the teeth, but the rare condition known as talon cusps are most prevalent on the maxillary lateral incisors. The surface area of the tooth used in eating is called an incisal ridge or incisal edge. Though relatively the same, there are some minor differences between the deciduous (baby) maxillary lateral incisor and that of the permanent maxillary lateral incisor. The maxillary lateral incisors occlude in opposition to the mandibular lateral incisors.
The maxillary first molar is the human tooth located laterally from both the maxillary second premolars of the mouth but mesial from both maxillary second molars.
The maxillary second molar is the tooth located distally from both the maxillary first molars of the mouth but mesial from both maxillary third molars. This is true only in permanent teeth. In deciduous (baby) teeth, the maxillary second molar is the last tooth in the mouth and does not have a third molar behind it. 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 four cusps on maxillary molars, two on the buccal and two palatal.
The mandibular central incisor is the tooth located on the jaw, adjacent to the midline of the face. It is mesial from both mandibular lateral incisors. As with all incisors, its function includes shearing or cutting food during mastication, commonly known as chewing. There are no cusps on the tooth. Instead, the surface area of the tooth used in eating is called an incisal ridge or incisal edge. Though the two are similar, there are some minor differences between the deciduous (baby) mandibular central incisor and that of the permanent mandibular central incisor. The mandibular central incisors are usually the first teeth to appear in the mouth, typically around the age of 6–8 months.
The mandibular canine is the tooth located distally from both mandibular lateral incisors of the mouth but mesially from both mandibular first premolars. Both the maxillary and mandibular canines are called the "cornerstone" of the mouth because they are all located three teeth away from the midline, and separate the premolars from the incisors. The location of the canines reflect their dual function as they complement both the premolars and incisors during mastication, commonly known as chewing. Nonetheless, the most common action of the canines is tearing of food. The canine teeth are able to withstand the tremendous lateral pressures from chewing. There is a single cusp on canines, and they resemble the prehensile teeth found in carnivorous animals. Though relatively the same, there are some minor differences between the deciduous (baby) mandibular canine and that of the permanent mandibular canine.
The mandibular first premolar is the tooth located laterally from both the mandibular canines of the mouth but mesial from both mandibular second premolars. The function of this premolar is similar to that of canines in regard to tearing being the principal action during mastication, commonly known as chewing. Mandibular first premolars have two cusps. The one large and sharp is located on the buccal side of the tooth. Since the lingual cusp is small and nonfunctional, the mandibular first premolar resembles a small canine. There are no deciduous (baby) mandibular premolars. Instead, the teeth that precede the permanent mandibular premolars are the deciduous mandibular molars.
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 describes 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.
The mandibular second molar is the tooth located distally from both the mandibular first molars of the mouth but mesial from both mandibular third molars. This is true only in permanent teeth. 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. Though there is more variation between individuals than that of the first mandibular molar, there are usually four cusps on mandibular second molars: two on the buccal and two lingual. There are great differences between the deciduous (baby) mandibular molars and those of the permanent mandibular molars, even though their function is similar. The permanent mandibular molars are not considered to have any teeth that precede them. Despite being named molars, the deciduous molars are followed by permanent premolars.
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.
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.
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.
Height of curvature in the tooth can be defined as the line encircling a tooth at its greatest bulge to a selected path of insertion. The height of curvature is the same as the height of contour.
In implant dentistry, running room refers to the apico-coronal distance between the platform of a dental implant and the gingival margin. It is a critical factor in restorative implant dentistry because it is effectively the "vertical distance [available subgingivaly] to make a transition from the smaller diameter prosthetic platform of an implant to the larger cross-sectional cervical shape of the tooth being restored." The term was coined by Jonathan Zamzok, a Manhattan prosthodontist, in the late 1990s.
The radix entomolaris is an additional root in human's mandibular molar teeth. The human mandibular teeth have two roots usually. In rare cases, however, a root may develop between the distal and the mesial roots which is called entomolaris, if it is located lingual to the tooth. Such a phenomenon is named radix paramolaris in case an extra root is buccal to a molar tooth. It is important to remember that an extra root can appear both in the first and second molars.
Tikitherium is an extinct genus of mammaliaforms from the Late Triassic. It is thought to be an insectivore and a close relative to Docodonta. Tikitherium refers to Tiki, the village located near the Tiki Formation where the specimen was found, and therium is Greek for “Beast”. The species was named copei in honor of Edward Drinker Cope for his pioneering discoveries towards understanding mammalian molars.
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