Malocclusion
Encyclopedia
A malocclusion is a misalignment of teeth or incorrect relation between the teeth of the two dental arches. The term was coined by Edward Angle
, the "father of modern orthodontics", as a derivative of occlusion, which refers to the manner in which opposing teeth meet.
) to correct the problem. Correction of malocclusion may reduce risk of tooth decay and help relieve excessive pressure on the temporomandibular joint
. Orthodontic treatment is also used to align for aesthetic reasons.
Malocclusions may be coupled with skeletal disharmony of the face, where the relations between the upper and lower jaws are not appropriate. Such skeletal disharmonies often distort sufferer's face shape, severely affect aesthetics of the face and may be coupled with mastication
or speech problems. In these cases the dental problem is, most of the time, derived from the skeletal disharmony. Most skeletal malocclusions can only be treated by orthognathic surgery.
Many authors have tried to classify or modify Angle's classification. This has resulted in many subtypes.
, who is considered the father of modern orthodontics, was the first to classify malocclusion. He based his classifications on the relative position of the maxillary first molar
. According to Angle, the mesiobuccal cusp
of the upper first molar should rest on the mesiobuccal groove
of the mandibular first molar. The teeth should all fit on a line of occlusion which is a smooth curve through the central fossae and cingulum of the upper canines, and through the buccal cusp and incisal edges of the mandible. Any variations from this resulted in malocclusion types. It is also possible to have different classes of malocclusion on left and right sides.
(milk, baby) teeth due to decay.
Other theories state that the malocclusion could be due to trauma during development that affects the permanent tooth bud, ectopic eruption of teeth, supernumerary teeth, and early loss of the primary tooth.
Recently, a paper suggested that "the changes in human skulls are more likely driven by the decreasing bite forces required to chew the processed foods eaten once humans switch to growing different types of cereals, milking and herding animals about 10,000 years ago."
, often with tooth extraction, dental braces, followed by growth modification in children or jaw surgery (orthognathic surgery
) in adults.
Malocclusions can also be secondary to transverse skeletal discrepancy or to a skeletal asymmetry.
or the maxilla
and mandible are etiological
factors in malocclusion.
In the active skeletal growth
mouthbreathing, finger
sucking, thumb
sucking, pacifier
sucking, onychophagia
(nail
biting), dermatophagia
, pen
biting, pencil
biting, abnormal posture
, deglutition disorders and other habits greatly influence the development of the face
and dental arches
.
Pacifier
sucking habits are also correlated with otitis media
.
Dental caries
, periapical inflammation
and tooth loss in the deciduous teeth
alter the correct permanent teeth eruptions
.
Edward Angle
Edward Hartley Angle was an American dentist, widely regarded as the father of modern orthodontics.Edward Angle is frequently described as "the father of modern orthodontics." He was trained as a dentist, but made orthodontics his speciality and dedicated his life to standardizing the teaching...
, the "father of modern orthodontics", as a derivative of occlusion, which refers to the manner in which opposing teeth meet.
Presentation
Most people have some degree of malocclusion, although it is not usually serious enough to require treatment. Those who have more severe malocclusions may require orthodontic and sometimes surgical treatment (orthognathic surgeryOrthognathic surgery
Orthognathic surgery is surgery to correct conditions of the jaw and face related to structure, growth, sleep apnea, TMJ disorders, malocclusion problems owing to skeletal disharmonies, or other orthodontic problems that cannot be easily treated with braces. Originally coined by Dr. Harold...
) to correct the problem. Correction of malocclusion may reduce risk of tooth decay and help relieve excessive pressure on the temporomandibular joint
Temporomandibular joint
The temporomandibular joint is the joint of the jaw and is frequently referred to as TMJ. There are two TMJs, one on either side, working in unison. The name is derived from the two bones which form the joint: the upper temporal bone which is part of the cranium , and the lower jaw bone called the...
. Orthodontic treatment is also used to align for aesthetic reasons.
Malocclusions may be coupled with skeletal disharmony of the face, where the relations between the upper and lower jaws are not appropriate. Such skeletal disharmonies often distort sufferer's face shape, severely affect aesthetics of the face and may be coupled with mastication
Mastication
Mastication or chewing 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 more efficient break down by enzymes. During the mastication process, the food is positioned between the teeth for grinding by...
or speech problems. In these cases the dental problem is, most of the time, derived from the skeletal disharmony. Most skeletal malocclusions can only be treated by orthognathic surgery.
Classification
Malocclusions can be divided mainly into three types, depending on the sagittal relations of teeth and jaws, by Angle's classification method. However, there are also other conditions e.g. crowding of teeth, not directly fitting into this classification.Many authors have tried to classify or modify Angle's classification. This has resulted in many subtypes.
Angle's classification method
Edward AngleEdward Angle
Edward Hartley Angle was an American dentist, widely regarded as the father of modern orthodontics.Edward Angle is frequently described as "the father of modern orthodontics." He was trained as a dentist, but made orthodontics his speciality and dedicated his life to standardizing the teaching...
, who is considered the father of modern orthodontics, was the first to classify malocclusion. He based his classifications on the relative position of the maxillary first molar
Maxillary first molar
The maxillary first molar is the tooth located laterally from both the maxillary second premolars of the mouth but mesial from both maxillary second molars....
. According to Angle, the mesiobuccal cusp
Commonly used terms of relationship and comparison in dentistry
There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...
of the upper first molar should rest on the mesiobuccal groove
Commonly used terms of relationship and comparison in dentistry
There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...
of the mandibular first molar. The teeth should all fit on a line of occlusion which is a smooth curve through the central fossae and cingulum of the upper canines, and through the buccal cusp and incisal edges of the mandible. Any variations from this resulted in malocclusion types. It is also possible to have different classes of malocclusion on left and right sides.
- Class I: Neutrocclusion Here the molar relationship of the occlusion is normal or as described for the maxillary first molar, but the other teeth have problems like spacing, crowding, over or under eruption, etc.
- Class II: Distocclusion (retrognathismRetrognathismRetrognathia is a type of malocclusion which refers to an abnormal posterior positioning of the maxilla or mandible, particularly the mandible, relative to the facial skeleton and soft tissues....
, overjet) In this situation, the upper molars are placed not in the mesiobuccal groove but anteriorly to it. Usually the mesiobuccal cusp rests in between the first mandibular molars and second premolars. There are two subtypes:- Class II Division 1: The molar relationships are like that of Class II and the anterior teeth are protruded.
- Class II Division 2: The molar relationships are class II but the central are retroclined and the lateral teeth are seen overlapping the centrals.
- Class III: Mesiocclusion (prognathismPrognathismPrognathism is a term used to describe the positional relationship of the mandible and/or maxilla to the skeletal base where either of the jaws protrudes beyond a predetermined imaginary line in the coronal plane of the skull. In general dentistry, oral and maxillofacial surgery and orthodontics...
, negative overjet) is when the lower front teeth are more prominent than the upper front teeth. In this case the patient very often has a large mandible or a short maxillary bone.
Crowding of teeth
Crowding of teeth is where there is insufficient room for the normal complement of adult teeth.Cause
Crowding of teeth is recognized as an affliction that stems in part from a modern western lifestyle. It is unknown whether it is due to the consistency of western diets, a result of mouthbreathing; or the result of an early loss of deciduousDeciduous teeth
Deciduous teeth, otherwise known as reborner teeth, baby teeth, temporary teeth and primary teeth, are the first set of teeth in the growth development of humans and many other mammals. In some Asian countries they are referred to as fall teeth as they will eventually fall out, while in almost all...
(milk, baby) teeth due to decay.
Other theories state that the malocclusion could be due to trauma during development that affects the permanent tooth bud, ectopic eruption of teeth, supernumerary teeth, and early loss of the primary tooth.
Recently, a paper suggested that "the changes in human skulls are more likely driven by the decreasing bite forces required to chew the processed foods eaten once humans switch to growing different types of cereals, milking and herding animals about 10,000 years ago."
Treatment
Crowding of the teeth is treated with orthodonticsOrthodontics
Orthodontics, orthodontia, or orthodonture is the first specialty of dentistry that is concerned with the study and treatment of malocclusions , which may be a result of tooth irregularity, disproportionate jaw relationships, or both...
, often with tooth extraction, dental braces, followed by growth modification in children or jaw surgery (orthognathic surgery
Orthognathic surgery
Orthognathic surgery is surgery to correct conditions of the jaw and face related to structure, growth, sleep apnea, TMJ disorders, malocclusion problems owing to skeletal disharmonies, or other orthodontic problems that cannot be easily treated with braces. Originally coined by Dr. Harold...
) in adults.
Other conditions
Other kinds of malocclusions are due to vertical discrepancies. Long faces may lead to open bite, while short faces can be coupled to a deep bite. However, there are many other more common causes for open bites (such as tongue thrusting and thumb sucking), and likewise for deep bites.Malocclusions can also be secondary to transverse skeletal discrepancy or to a skeletal asymmetry.
Etiology
Oral habits and pressure on teethTooth
Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...
or the maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
and mandible are etiological
Etiology
Etiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....
factors in malocclusion.
In the active skeletal growth
Human development (biology)
Human development is the process of growing to maturity. In biological terms, this entails growth from a one-celled zygote to an adult human being.- Biological development:...
mouthbreathing, finger
Finger
A finger is a limb of the human body and a type of digit, an organ of manipulation and sensation found in the hands of humans and other primates....
sucking, thumb
Thumb
The thumb is the first digit of the hand. When a person is standing in the medical anatomical position , the thumb is the lateral-most digit...
sucking, pacifier
Pacifier
A pacifier is a rubber, plastic, or silicone nipple given to an infant or other young child to suck upon. In its standard appearance it has a teat, mouth shield, and handle...
sucking, onychophagia
Nail biting
Onychophagia, or nail biting, is a common oral compulsive habit in children and adults.-Classification:Nail biting is considered an impulse control disorder in the DSM-IV-R; the ICD-10 classifies it as "other specified behavioral and emotional disorders with onset usually occurring in childhood and...
(nail
Nail (anatomy)
A nail is a horn-like envelope covering the dorsal aspect of the terminal phalanges of fingers and toes in humans, most non-human primates, and a few other mammals. Nails are similar to claws, which are found on numerous other animals....
biting), dermatophagia
Dermatophagia
Dermatophagia is a form of obsessive-compulsive disorder wherein a sufferer compulsively bites their own skin. Sufferers typically bite the skin around the nails, leading to bleeding and discoloration over time....
, pen
Pen
A pen is a device used to apply ink to a surface, usually paper, for writing or drawing. Historically, reed pens, quill pens, and dip pens were used, with a nib of some sort to be dipped in the ink. Ruling pens allow precise adjustment of line width, and still find a few specialized uses, but...
biting, pencil
Pencil
A pencil is a writing implement or art medium usually constructed of a narrow, solid pigment core inside a protective casing. The case prevents the core from breaking, and also from marking the user’s hand during use....
biting, abnormal posture
Human position
Human positions refers to the different positions that the human body can take.There are several synonyms that refer to the human position, often used interchangeably, but having specific flavors....
, deglutition disorders and other habits greatly influence the development of the face
Face
The face is a central sense organ complex, for those animals that have one, normally on the ventral surface of the head, and can, depending on the definition in the human case, include the hair, forehead, eyebrow, eyelashes, eyes, nose, ears, cheeks, mouth, lips, philtrum, temple, teeth, skin, and...
and dental arches
Dental arches
The superior dental arch is larger than the inferior, so that in the normal condition the teeth in the maxillae slightly overlap those of the mandible both in front and at the sides....
.
Pacifier
Pacifier
A pacifier is a rubber, plastic, or silicone nipple given to an infant or other young child to suck upon. In its standard appearance it has a teat, mouth shield, and handle...
sucking habits are also correlated with otitis media
Otitis media
Otitis media is inflammation of the middle ear, or a middle ear infection.It occurs in the area between the tympanic membrane and the inner ear, including a duct known as the eustachian tube. It is one of the two categories of ear inflammation that can underlie what is commonly called an earache,...
.
Dental caries
Dental caries
Dental caries, also known as tooth decay or a cavity, is an irreversible infection usually bacterial in origin that causes demineralization of the hard tissues and destruction of the organic matter of the tooth, usually by production of acid by hydrolysis of the food debris accumulated on the...
, periapical inflammation
Periapical abscess
A periapical abscess is the result of a chronic, localized infection located at the tip, or apex, of the root of a tooth.To achieve resolution, endodontic therapy must be performed to debride the root canal or canals and remove pathogens....
and tooth loss in the deciduous teeth
Deciduous teeth
Deciduous teeth, otherwise known as reborner teeth, baby teeth, temporary teeth and primary teeth, are the first set of teeth in the growth development of humans and many other mammals. In some Asian countries they are referred to as fall teeth as they will eventually fall out, while in almost all...
alter the correct permanent teeth eruptions
Tooth eruption
Tooth eruption is a process in tooth development in which the teeth enter the mouth and become visible. It is currently believed that the periodontal ligaments play an important role in tooth eruption...
.