Torus mandibularis is a bony growth in the mandible along the surface nearest to the tongue. Mandibular tori are present near the premolars and above the location of the mylohyoid muscle's attachment to the mandible. In 90% of cases, there is a torus on both the left and right sides, making this finding a predominantly bilateral condition; the prevalence of mandibular tori ranges from 5% - 40%. It is less common than bony growths occurring on the palate, known as torus palatinus. Mandibular tori are more common in Asian and Inuit populations, more common in males. In the United States, the prevalence is 7% - 10% of the population, it is believed. They are associated with bruxism; the size of the tori may fluctuate throughout life, in some cases the tori can be large enough to touch each other in the midline of mouth. It is believed that mandibular tori are the result of local stresses and not due to genetic influences. Mandibular tori are a clinical finding with no treatment necessary, it is possible for ulcers to form in the area of the tori due to trauma.
The tori may complicate the fabrication of dentures. If removal of the tori is needed, surgery can be done to reduce the amount of bone, but the tori may reform in cases where nearby teeth still receive local stresses. Marquette University School of Dentistry - Oral & Maxiollofacial Pathology, What Could This Be? What are mandibular tori
Medical genetics is the branch of medicine that involves the diagnosis and management of hereditary disorders. Medical genetics differs from human genetics in that human genetics is a field of scientific research that may or may not apply to medicine, while medical genetics refers to the application of genetics to medical care. For example, research on the causes and inheritance of genetic disorders would be considered within both human genetics and medical genetics, while the diagnosis and counselling people with genetic disorders would be considered part of medical genetics. In contrast, the study of non-medical phenotypes such as the genetics of eye color would be considered part of human genetics, but not relevant to medical genetics. Genetic medicine is a newer term for medical genetics and incorporates areas such as gene therapy, personalized medicine, the emerging new medical specialty, predictive medicine. Medical genetics encompasses many different areas, including clinical practice of physicians, genetic counselors, nutritionists, clinical diagnostic laboratory activities, research into the causes and inheritance of genetic disorders.
Examples of conditions that fall within the scope of medical genetics include birth defects and dysmorphology, mental retardation, mitochondrial disorders, skeletal dysplasia, connective tissue disorders, cancer genetics and prenatal diagnosis. Medical genetics is becoming relevant to many common diseases. Overlaps with other medical specialties are beginning to emerge, as recent advances in genetics are revealing etiologies for neurologic, cardiovascular, ophthalmologic, renal and dermatologic conditions; the medical genetics community is involved with individuals who have undertaken elective genetic and genomic testing. In some ways, many of the individual fields within medical genetics are hybrids between clinical care and research; this is due in part to recent advances in science and technology that have enabled an unprecedented understanding of genetic disorders. Clinical genetics is the practice of clinical medicine with particular attention to hereditary disorders. Referrals are made to genetics clinics for a variety of reasons, including birth defects, developmental delay, epilepsy, short stature, many others.
Examples of genetic syndromes that are seen in the genetics clinic include chromosomal rearrangements, Down syndrome, DiGeorge syndrome, Fragile X syndrome, Marfan syndrome, Neurofibromatosis, Turner syndrome, Williams syndrome. In the United States, Doctors who practice clinical genetics are accredited by the American Board of Medical Genetics and Genomics. In order to become a board-certified practitioner of Clinical Genetics, a physician must complete a minimum of 24 months of training in a program accredited by the ABMGG. Individuals seeking acceptance into clinical genetics training programs must hold an M. D. or D. O. degree and have completed a minimum of 24 months of training in an ACGME-accredited residency program in internal medicine, pediatrics and gynecology, or other medical specialty. Metabolic genetics involves the diagnosis and management of inborn errors of metabolism in which patients have enzymatic deficiencies that perturb biochemical pathways involved in metabolism of carbohydrates, amino acids, lipids.
Examples of metabolic disorders include galactosemia, glycogen storage disease, lysosomal storage disorders, metabolic acidosis, peroxisomal disorders and urea cycle disorders. Cytogenetics is the study of chromosomes and chromosome abnormalities. While cytogenetics relied on microscopy to analyze chromosomes, new molecular technologies such as array comparative genomic hybridization are now becoming used. Examples of chromosome abnormalities include aneuploidy, chromosomal rearrangements, genomic deletion/duplication disorders. Molecular genetics involves the discovery of and laboratory testing for DNA mutations that underlie many single gene disorders. Examples of single gene disorders include achondroplasia, cystic fibrosis, Duchenne muscular dystrophy, hereditary breast cancer, Huntington disease, Marfan syndrome, Noonan syndrome, Rett syndrome. Molecular tests are used in the diagnosis of syndromes involving epigenetic abnormalities, such as Angelman syndrome, Beckwith-Wiedemann syndrome, Prader-willi syndrome, uniparental disomy.
Mitochondrial genetics concerns the diagnosis and management of mitochondrial disorders, which have a molecular basis but result in biochemical abnormalities due to deficient energy production. There exists some overlap between molecular pathology. Genetic counseling is the process of providing information about genetic conditions, diagnostic testing, risks in other family members, within the framework of nondirective counseling. Genetic counselors are non-physician members of the medical genetics team who specialize in family risk assessment and counseling of patients regarding genetic disorders; the precise role of the genetic counselor varies somewhat depending on the disorder. Although genetics has its roots back in the 19th century with the work of the Bohemian monk Gregor Mendel and other pioneering scientists, human genetics emerged later, it started to develop, albeit during the first half of the 20th century. Mendelian inheritance was studied in a number of important disorders such as albinism and hemophilia.
Mathematical approaches were devised
Orthodontics and dentofacial orthopedics referred to as orthodontia, is a specialty of dentistry that deals with the diagnosis and correction of malpositioned teeth and jaws. The field was established by such pioneering orthodontists as Edward Angle and Norman William Kingsley. "Orthodontics" is derived from the Greek orthos and -odont. The history of orthodontics has been intimately linked with the history of dentistry for more than 2,000 years. Dentistry had its origins as a part of medicine. According to the American Association of Orthodontists, archaeologists have discovered mummified ancients with metal bands wrapped around individual teeth. Malocclusion is not a disease, but abnormal alignment of the teeth and the way the upper and lower teeth fit together; the prevalence of malocclusion varies, but using orthodontic treatment indices, which categorize malocclusions in terms of severity, it can be said that nearly 30% of the population present with malocclusions severe enough to benefit from orthodontic treatment.
Orthodontic treatment can focus on dental displacement only, or deal with the control and modification of facial growth. In the latter case it is better defined as "dentofacial orthopedics". In severe malocclusions that can be a part of craniofacial abnormality, management requires a combination of orthodontics with headgear or reverse pull facemask and/or jaw surgery or orthognathic surgery; this requires additional training, in addition to the formal three-year specialty training. For instance, in the United States, orthodontists get at least another year of training in a form of fellowship, the so-called'Craniofacial Orthodontics', to receive additional training in the orthodontic management of craniofacial anomalies. Treatment for malocclusion can take anywhere from 1 to 3 years to complete, with braces being altered every 4 to 10 weeks by the orthodontist. There are multiple methods for adjusting malocclusion, depending on the needs of the individual patient. In growing patients there are more options for treating skeletal discrepancies, either promoting or restricting growth using functional appliances, orthodontic headgear or a reverse pull facemask.
Most orthodontic work is started during the early permanent dentition stage before skeletal growth is completed. If skeletal growth has completed, orthognathic surgery can be an option. Extraction of teeth may be required to aid the orthodontic treatment. Starting the treatment process for overjets and prominent upper teeth in children rather than waiting until the child has reached adolescence has been shown to reduce damage to the lateral and central incisors; however the treatment outcome does not differ. The majority of Orthodontic Appliance Therapy is delivered using fixed appliances, with the use of removable appliances being reduced; the treatment outcome for fixed appliances is greater than that of removable appliances as the fixed type produces biomechanics that has greater control of the teeth under treatment: being able to move the teeth in dimensions therefore the subsequent final tooth positions are more ideal. Indications for Fixed Appliances Fixed appliances are used when orthodontic treatment involves moving teeth through 3 axis planes in the mouth.
These movements would include: 1) Rotations where the teeth are not conforming to the arch shape and there are contact displacements. 2) Multiple tooth movements where there may be crowding involved and the correction would involve the movement of numerous teeth in differing planes. 3) Bodily movement may be required to move a map-aligned tooth into the arch where the broad long axis of the tooth are correct but the tooth requires moving back into the arch maintaining the axial positions. 4) Tipping or changing the incline of the long axis of the tooth where the tooth may be proclined or retroclined and the tooth angulation is altered. 5) Root torquing - where the angle of the long axis of the tooth is changed with the position of the root being altered to facilitate a more positioned crown and root prominence. Contra-indications - Poor oral hygiene: this predisposes to decalcification, gingival hyperplasia, periodontal breakdown - Active caries - Poor motivation: treatment will last at least several months, patient needs to be committed to maintaining the highest levels of oral hygiene throughout this period.
- Mild malocclusions Risks DecalcificationPlaque accumulation around the margins of brackets and bands can result in areas of demineralisation of enamel. It is important that the patient maintains an excellent standard of oral hygiene throughout treatment. Root ResorptionThis occurs in orthodontic treatment, although it is small in amount, it is an irreversible outcome, difficult to predict. Fixed appliances cause more root resorption than removable appliances. Resorption occurs more in adults and with greater amounts of tooth movement. Root resorption stops as soon. Loss of periodontal support Loss of bone support Failed treatment Soft tissue traumaTypes of Fixed Appliances There are numerous fixed appliance systems that are in use today; these vary depending on personal preference. In basic terms, a bracket is bonded onto the center of the tooth and wires are placed in the bracket slot in order to control movement in all 3 dimensions; each individual bracket has a different shape and built in features for each particular tooth.
Chair-side fitted appliances include Edgewise, Lingual, Self-ligating bracket systems. Laboratory fabricated appliances include Herbst, Quadhelix and MIA, Lingual and Transpalatal arches and RME screw appliances
The mandible, lower jaw or jawbone is the largest and lowest bone in the human face. It holds the lower teeth in place; the mandible sits beneath the maxilla. It is the only movable bone of the skull; the bone is formed in the fetus from a fusion of the left and right mandibular prominences, the point where these sides join, the mandibular symphysis, is still visible as a faint ridge in the midline. Like other symphyses in the body, this is a midline articulation where the bones are joined by fibrocartilage, but this articulation fuses together in early childhood; the word "mandible" derives from the Latin word mandibula, "jawbone", from mandere "to chew" and -bula. The mandible consists of: The body, found at the front A ramus on the left and the right, the rami rise up from the body of the mandible and meet with the body at the angle of the mandible or the gonial angle; the body of the mandible is curved, the front part gives structure to the chin. It has two borders. From the outside, the mandible is marked in the midline by a faint ridge, indicating the mandibular symphysis, the line of junction of the two pieces of which the bone is composed at an early period of life.
This ridge divides below and encloses a triangular eminence, the mental protuberance, the base of, depressed in the center but raised on either side to form the mental tubercle. On either side of the symphysis, just below the incisor teeth, is a depression, the incisive fossa, which gives origin to the mentalis and a small portion of the orbicularis oris. Below the second premolar tooth, on either side, midway between the upper and lower borders of the body, is the mental foramen, for the passage of the mental vessels and nerve. Running backward and upward from each mental tubercle is a faint ridge, the oblique line, continuous with the anterior border of the ramus. From the inside, the mandible appears concave. Near the lower part of the symphysis is a pair of laterally placed spines, termed the mental spines, which give origin to the genioglossus. Below these is a second pair of spines, or more a median ridge or impression, for the origin of the geniohyoid. In some cases, the mental spines are fused to form a single eminence, in others they are absent and their position is indicated by an irregularity of the surface.
Above the mental spines, a median foramen and furrow are sometimes seen. Below the mental spines, on either side of the middle line, is an oval depression for the attachment of the anterior belly of the digastric. Extending upward and backward on either side from the lower part of the symphysis is the mylohyoid line, which gives origin to the mylohyoid muscle. Above the anterior part of this line is a smooth triangular area against which the sublingual gland rests, below the hinder part, an oval fossa for the submandibular gland. Borders The superior or alveolar border, wider behind than in front, is hollowed into cavities, for the reception of the teeth. To the outer lip of the superior border, on either side, the buccinator is attached as far forward as the first molar tooth; the inferior border is rounded, longer than the superior, thicker in front than behind. The ramus of the human mandible has four sides, two surfaces, four borders, two processes. On the outside, the ramus marked by oblique ridges at its lower part.
On the inside at the center there is an oblique mandibular foramen, for the entrance of the inferior alveolar vessels and nerve. The margin of this opening is irregular. Behind this groove is a rough surface, for the insertion of the medial pterygoid muscle; the mandibular canal runs obliquely downward and forward in the ramus, horizontally forward in the body, where it is placed under the alveoli and communicates with them by small openings. On arriving at the incisor teeth, it turns back to communicate with the mental foramen, giving off two small canals which run to the cavities containing the incisor teeth. In the posterior two-thirds of the bone the canal is situated nearer the internal surface of the mandible, it contains the inferior alveolar vessels and nerve, from which branches are distributed to the teeth. Borders The lower border of the ramus is thick and continuous with the inferior border of the body of the bone. At its junction with the posterior border is the angle of the mandible, which may be either inverted or everted and is marked by rough, oblique ridges on each side, for the attachment of the masseter laterally, the medial pterygoid muscle medially.
The anterior border is thin above, thicker below, continuous with the oblique l
The jaw is any opposable articulated structure at the entrance of the mouth used for grasping and manipulating food. The term jaws is broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of most animals. In arthropods, the jaws are chitinous and oppose laterally, may consist of mandibles or chelicerae; these jaws are composed of numerous mouthparts. Their function is fundamentally for food acquisition, conveyance to the mouth, and/or initial processing. Many mouthparts and associate structures are modified legs. In most vertebrates, the jaws are bony or cartilaginous and oppose vertically, comprising an upper jaw and a lower jaw; the vertebrate jaw is derived from the most anterior two pharyngeal arches supporting the gills, bears numerous teeth. The vertebrate jaw originally evolved in the Silurian period and appeared in the Placoderm fish which further diversified in the Devonian; the two most anterior pharyngeal arches are thought to have become the jaw itself and the hyoid arch, respectively.
The hyoid system suspends the jaw from the braincase of the skull, permitting great mobility of the jaws. While there is no fossil evidence directly to support this theory, it makes sense in light of the numbers of pharyngeal arches that are visible in extant jawed vertebrates, which have seven arches, primitive jawless vertebrates, which have nine; the original selective advantage offered by the jaw may not be related to feeding, but rather to increased respiration efficiency. The jaws were used in the buccal pump that pumps water across the gills of fish or air into the lungs in the case of amphibians. Over evolutionary time the more familiar use of jaws, in feeding, was selected for and became a important function in vertebrates. Many teleost fish have modified jaws for suction feeding and jaw protrusion, resulting in complex jaws with dozens of bones involved; the jaw in tetrapods is simplified compared to fish. Most of the upper jaw bones have been fused to the braincase, while the lower jaw bones have been fused together into a unit called the mandible.
The jaw articulates via a hinge joint between the articular. The jaws of tetrapods exhibit varying degrees of mobility between jaw bones; some species have jaw bones fused, while others may have joints allowing for mobility of the dentary, quadrate, or maxilla. The snake skull shows the greatest degree of cranial kinesis, which allows the snake to swallow large prey items. In mammals the jaws are made up of the maxilla. In the ape there is a reinforcement to the lower jaw bone called the simian shelf. In the evolution of the mammalian jaw, two of the bones of the jaw structure were reduced in size and incorporated into the ear, while many others have been fused together; as a result, mammals show little or no cranial kinesis, the mandible is attached to the temporal bone by the temporomandibular joints. Temporomandibular joint dysfunction is a common disorder of these joints, characterized by pain and limitation of mandibular movement. Sea urchins possess unique jaws which display five-part symmetry, termed the Aristotle's lantern.
Each unit of the jaw holds a single, perpetually growing tooth composed of crystalline calcium carbonate. Muscles of mastication Otofacial syndrome Predentary Prognathism Rostral bone Jaw at the US National Library of Medicine Medical Subject Headings