Prognathism

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Prognathism
Other namesHabsburg jaw (in the case of mandibular prognathism)
Prognathism3.png
Illustration of different types
Specialty Orthodontics   OOjs UI icon edit-ltr-progressive.svg
Types
  • Alveolar
  • Maxillary
  • Mandibular or progenism
CausesMultifactorial
Treatment Orthodontics; oral and maxillofacial surgery
Frequency
  • Children: 0.5 to 2.0%
  • Adult: 2.0 to 4.0% [1]

Prognathism is a positional relationship of the mandible or maxilla to the skeletal base where either of the jaws protrudes beyond a predetermined imaginary line in the coronal plane of the skull.[ clarification needed ]

Contents

In the case of mandibular prognathism (never maxillary prognathism) this is often also referred to as Habsburg chin, Habsburg's chin, Habsburg jaw or Habsburg's jaw [2] [3] especially when referenced with context of its prevalence amongst historical members of the House of Habsburg. [2]

Mandibular prognathism is typically pathological, whereas maxillary prognathism is often found as a result of normal human population variation.

In general dentistry, oral and maxillofacial surgery, and orthodontics, this is assessed clinically or radiographically (cephalometrics). The word prognathism derives from Greek πρό (pro, meaning 'forward') and γνάθος (gnáthos, 'jaw'). One or more types of prognathism can result in the common condition of malocclusion, in which an individual's top teeth and lower teeth do not align properly.[ citation needed ]

Presentation

Mandibular prognathism, where teeth have almost reached their final, straight position by dental braces, making the prognathism more obvious. Mandibular prognathism pre-surgery.png
Mandibular prognathism, where teeth have almost reached their final, straight position by dental braces, making the prognathism more obvious.

In humans, non-pathological maxillary and alveolar prognathism can occur due to normal variation among phenotypes.

However, mandibular prognathism is usually anomalous, and it may be a malformation, the result of injury, a disease state, or a hereditary condition. [4]

Prognathism is considered a disorder only if it affects chewing, speech or social function as a byproduct of severely affected aesthetics of the face.[ citation needed ]

Clinical determinants include soft tissue analysis where the clinician assesses nasolabial angle, the relationship of the soft tissue portion of the chin to the nose, and the relationship between the upper and lower lips; also used is dental arch relationship assessment such as Angle's classification.[ citation needed ]

Cephalometric analysis is the most accurate way of determining all types of prognathism, as it includes assessments of skeletal base, occlusal plane angulation, facial height, soft tissue assessment and anterior dental angulation. Various calculations and assessments of the information in a cephalometric radiograph allow the clinician to objectively determine dental and skeletal relationships and determine a treatment plan.[ citation needed ]

Prognathism should not be confused with micrognathism, although combinations of both are found.

Alveolar prognathism is a protrusion of that portion of the maxilla where the teeth are located, in the dental lining of the upper jaw.[ citation needed ]

Maxillary prognathism affects the middle third of the face, causing the maxilla to jut out, thereby increasing the facial area.

Mandibular prognathism is a protrusion of the mandible, affecting the lower third of the face.

Prognathism can also be used to describe ways that the maxillary and mandibular dental arches relate to one another, including malocclusion (where the upper and lower teeth do not align). When there is maxillary or alveolar prognathism which causes an alignment of the maxillary incisors significantly anterior to the lower teeth, the condition is called an overjet. When the reverse is the case, and the lower jaw extends forward beyond the upper, the condition is referred to as retrognathia (reverse overjet).[ citation needed ]

Classification

Alveolar prognathism

Alveolar prognathism, caused by thumb sucking and tongue thrusting in a seven-year-old girl. Alveolprog.jpg
Alveolar prognathism, caused by thumb sucking and tongue thrusting in a seven-year-old girl.

Not all alveolar prognathism is anomalous, and significant differences can be observed among different ethnicities. [5]

Harmful habits such as thumb sucking or tongue thrusting can result in or exaggerate an alveolar prognathism, causing teeth to misalign. [6] Functional appliances can be used in growing children to help modify bad habits and neuro-muscular function, with the aim of correcting this condition. [6]

Alveolar prognathism can also easily be corrected with fixed orthodontic therapy. However, relapse is quite common, unless the cause is removed or a long-term retention is used. [7]

Maxillary prognathism

In disease states, maxillary prognathism is associated with Cornelia de Lange syndrome; [8] however, so-called false maxillary prognathism, or more accurately, retrognathism, where there is a lack of growth of the mandible, is by far a more common condition.[ citation needed ]

Prognathism, if not extremely severe, can be treated in growing patients with orthodontic functional or orthopaedic appliances. In adult patients this condition can be corrected by means of a combined surgical/orthodontic treatment, where most of the time a mandibular advancement is performed. The same can be said for mandibular prognathism.[ citation needed ]

On average, Neanderthals were far more prognathic than modern humans regarding the maxilla. This maxillary prognathism, along with their wide noses, suggests that their faces were not adapted to cold climate. [9]

Mandibular prognathism (progenism)

Leopold I, showing progenism Berlin DHM Leopoldo I 02.JPG
Leopold I, showing progenism

Mandibular prognathism is a potentially disfiguring genetic disorder where the lower jaw outgrows the upper, resulting in an extended chin and a crossbite. In both humans and animals, it can be the result of inbreeding. [10]

Unlike alveolar or maxillary prognathism, which are common traits in some populations, mandibular prognathism is typically pathological. However, it is more common among East Asian populations but overall, the condition is polygenic. [11]

In brachycephalic or flat-faced dogs, like shih tzus and boxers, it can lead to problems such as underbite. [12]

In humans, it results in a condition sometimes called lantern jaw, reportedly derived from 15th century horn lanterns, which had convex sides. [13] [a] Traits such as these were often exaggerated by inbreeding, and can be traced within specific families. [10]

Although more common than appreciated, the best known historical example is Habsburg jaw, or Habsburg or Austrian lip, due to its prevalence in members of the House of Habsburg, which can be traced in their portraits. [15] The process of portrait-mapping has provided tools for geneticists and pedigree analysis; most instances are considered polygenic, [16] but a number of researchers believe that this trait is transmitted through an autosomal recessive type of inheritance. [17] [15]

Allegedly introduced into the family by a member of the Piast dynasty, it is clearly visible on family tomb sculptures in St. John's Cathedral, Warsaw. A high propensity for politically motivated intermarriage among Habsburgs meant the dynasty was virtually unparalleled in the degree of its inbreeding. Charles II of Spain, who lived 1661 to 1700, is said to have had the most pronounced case of the Habsburg jaw on record, [18] due to the high number of consanguineous marriages in the dynasty preceding his birth. [17] [15]

Charles II.jpg
Charles II of Spain showing Habsburg jaw, a severe type of mandibular prognathism.
Vlad Tepes 002.jpg
Vlad III of Wallachia, showing progenism.
Arveprins Frederik (Juel).JPG
Frederick, regent of Denmark-Norway, showing progenism.
Pedro II of Brazil 1851 edit.png
Pedro II of Brazil, showing progenism. His mother was Archduchess Maria Leopoldina of Austria, a member of the House of Habsburg-Lorraine by birth.

Treatment of mandibular prognathism

Prior to the development of modern dentistry, there was no treatment for this condition; those who had it simply endured it. Today, the most common treatment for mandibular prognathism is a combination of orthodontics and orthognathic surgery. The orthodontics can involve braces, removal of teeth, or a mouthguard. [19]

In insects

In entomology, prognathous means that the mouthparts face forwards, being at the front of the head, rather than facing downwards as in some insects. [20]

See also

Footnotes

  1. ↑ The OED uses a slightly different definition: "long thin jaws, giving a hollow appearance to the cheek". [14]

Related Research Articles

<span class="mw-page-title-main">Orthodontics</span> Correctional branch of dentistry

Orthodontics is a dentistry specialty that addresses the diagnosis, prevention, management, and correction of mal-positioned teeth and jaws, as well as misaligned bite patterns. It may also address the modification of facial growth, known as dentofacial orthopedics.

Hypodontia is defined as the developmental absence of one or more teeth excluding the third molars. It is one of the most common dental anomalies, and can have a negative impact on function, and also appearance. It rarely occurs in primary teeth and the most commonly affected are the adult second premolars and the upper lateral incisors. It usually occurs as part of a syndrome that involves other abnormalities and requires multidisciplinary treatment.

<span class="mw-page-title-main">Orthognathic surgery</span> Surgery of the jaw

Orthognathic surgery, also known as corrective jaw surgery or simply jaw surgery, is surgery designed to correct conditions of the jaw and lower face related to structure, growth, airway issues including sleep apnea, TMJ disorders, malocclusion problems primarily arising from skeletal disharmonies, and other orthodontic dental bite problems that cannot be treated easily with braces, as well as the broad range of facial imbalances, disharmonies, asymmetries, and malproportions where correction may be considered to improve facial aesthetics and self-esteem.

<span class="mw-page-title-main">Malocclusion</span> Misalignment between upper and lower teeth as the jaws close

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'.

<span class="mw-page-title-main">Palatal expansion</span> Orthodontics device to widen the upper jaw

A palatal expander is a device in the field of orthodontics which is used to widen the upper jaw (maxilla) so that the bottom and upper teeth will fit together better. This is a common orthodontic procedure. The use of an expander is most common in children and adolescents 8–18 years of age. It can also be used in adults, although expansion is more uncomfortable and takes longer in adults. A patient who would rather not wait several months for the end result achieved by a palatal expander may be able to opt for a surgical separation of the maxilla. Use of a palatal expander is most often followed by braces to then straighten the teeth.

Orthodontic technology is a specialty of dental technology that is concerned with the design and fabrication of dental appliances for the treatment of malocclusions, which may be a result of tooth irregularity, disproportionate jaw relationships, or both.

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.

<span class="mw-page-title-main">Overjet</span> Extent of horizontal overlap of the top and bottom front teeth (incisors)

In dentistry, overjet is the extent of horizontal (anterior-posterior) overlap of the maxillary central incisors over the mandibular central incisors. In class II malocclusion the overjet is increased as the maxillary central incisors are protruded.

<span class="mw-page-title-main">Crossbite</span> Left-right misalignment of upper and lower teeth

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.

Cephalometric analysis is the clinical application of cephalometry. It is analysis of the dental and skeletal relationships of a human skull. It is frequently used by dentists, orthodontists, and oral and maxillofacial surgeons as a treatment planning tool. Two of the more popular methods of analysis used in orthodontology are the Steiner analysis and the Downs analysis. There are other methods as well which are listed below.

Cecil C. Steiner was a dentist and one of Edward H. Angle's first students in 1921. He developed a form of cephalometric analysis, presented in 1953, referred to as the Steiner method of analysis.

<span class="mw-page-title-main">Jaw abnormality</span> Medical condition

A jaw abnormality is a disorder in the formation, shape and/or size of the jaw. In general abnormalities arise within the jaw when there is a disturbance or fault in the fusion of the mandibular processes. The mandible in particular has the most differential typical growth anomalies than any other bone in the human skeleton. This is due to variants in the complex symmetrical growth pattern which formulates the mandible.

<span class="mw-page-title-main">Overbite</span> Overlap of the maxillary central incisors over the mandibular central incisors

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.

Clifford Ballard was a British orthodontist. He became England's first Professor of Orthodontics in 1956. He served as the President of BSSO in 1957.

Elastics are rubber bands frequently used in the field of orthodontics to correct different types of malocclusions. The elastic wear is prescribed by an orthodontist or a dentist in an orthodontic treatment. The longevity of the elastic wear may vary from two weeks to several months. The elastic wear can be worn from 12 to 23 hours a day, either during the night or throughout the day depending on the requirements for each malocclusion. The many different types of elastics may produce different forces on teeth. Therefore, using elastics with specific forces is critical in achieving a good orthodontic occlusion.

Frankel appliance or Frankel Functional Regulator is an orthodontic functional appliance which was developed by Rolf Fränkel in 1950s for treatment to patients of all ages. This appliance primarily focused on the modulation of neuromuscular activity in order to produce changes in jaw and teeth. The appliance was opposite to the Activator appliance and Bionator appliance.

Open bite is a type of orthodontic malocclusion which has been estimated to occur in 0.6% of the people in the United States. This type of malocclusion has no vertical overlap or contact between the anterior incisors. The term "open bite" was coined by Carevelli in 1842 as a distinct classification of malocclusion. Different authors have described the open bite in a variety of ways. Some authors have suggested that open bite often arises when overbite is less than the usual amount. Additionally, others have contended that open bite is identified by end-on incisal relationships. Lastly, some researchers have stated that a lack of incisal contact must be present to diagnose an open bite.

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.

The Herbst appliance is an orthodontic appliance used by orthodontists to correct class 2 retrognathic mandible in a growing patient, meaning that the lower jaw is too far back. This is also called bitejumping. Herbst appliance parts include stainless steel surgical frameworks that are secured onto the teeth by bands or acrylic bites. These are connected by sets of telescoping mechanisms that apply gentle upward and backward force on the upper jaw, and forward force on the lower jaw. The original bite-jumping appliance was designed by Dr. Emil Herbst and reintroduced by Dr. Hans Pancherz using maxillary and mandibular first molars and first bicuspids. The bands were connected with heavy wire soldered to each band and carried a tube and piston assembly that allowed mandibular movement but permanently postured the mandible forward. The appliance not only corrected a dental Class II to a dental Class I but also offered a marked improvement of the classic Class II facial profile.

References

  1. ↑ Wolff, Wienker & Sander 1993, p. 112.
  2. 1 2 Peacock, Zachary S.; Klein, Katherine P.; Mulliken, John B.; Kaban, Leonard B. (September 2014). "The Habsburg Jaw-re-examined". American Journal of Medical Genetics. Part A. 164A (9): 2263–2269. doi:10.1002/ajmg.a.36639. PMID   24942320. S2CID   35651759.
  3. ↑ Zamudio Martínez, Gabriela; Zamudio Martínez, Adriana (2020). "A Royal Family Heritage: The Habsburg Jaw". Facial Plastic Surgery & Aesthetic Medicine. 22 (2): 120–121. doi:10.1089/fpsam.2019.29017.mar. PMID   32083497. S2CID   211232475.
  4. ↑ MedlinePlus Encyclopedia : Prognathism
  5. ↑ Vioarsdóttir, O'Higgins & Stringer 2002, pp. 211–229.
  6. 1 2 Singh, Tenali Sushmitha; Sridevi, Enuganti; Sankar, Avula Jogendra Sai; Kakarla, Pranitha; Vallabaneni, Siva Sai Krishna; Sridhar, Mukthineni (2020). "Cephalometric Assessment of Dentoskeletal Characteristics in Children with Digit-sucking Habit". International Journal of Clinical Pediatric Dentistry. 13 (3): 221–224. doi:10.5005/jp-journals-10005-1761. ISSN   0974-7052. PMC   7450188 . PMID   32904107.
  7. ↑ Sahil, Sahil; Soni, Sanjeev; Kaur, Gurpreet (2021-12-31). "Challenging Malocclusion in Orthodontics: the Open Bite". International Journal of Health Sciences: 125–134. doi: 10.53730/ijhs.v5nS2.5581 . ISSN   2550-6978.
  8. ↑ "Medical Definition of de Lange syndrome". MedicineNet.
  9. ↑ Rae, Todd C.; Koppe, Thomas; Stringer, Chris B. (27 October 2010). "The Neanderthal face is not cold adapted" (PDF). Moodle USP: e-Disciplinas. Retrieved 5 May 2024.
  10. 1 2 Vilas et al. 2019, pp. 563–571.
  11. ↑ Kulkarni, Shilpa Devdatt; Bhad, Wasundhara A.; Doshi, Umal H. (2020). "Association Between Mandibular Prognathism and MATRILIN-1 Gene in Central India Population: A Cross-sectional Study". Journal of Indian Orthodontic Society. 55 (1): 28–32. doi: 10.1177/0301574220956421 .
  12. ↑ Beuchat 2015.
  13. ↑ Online Mendelian Inheritance in Man (OMIM): PROGNATHISM, MANDIBULAR - 176700
  14. ↑ "lantern jaw" . Oxford English Dictionary (Online ed.). Oxford University Press.(Subscription or participating institution membership required.)
  15. 1 2 3 Vilas et al. 2019.
  16. ↑ Wolff, Wienker & Sander 1993, pp. 112–116.
  17. 1 2 Безуглый, Т. А. (2020). "Влияние На Человека Признаков, Передаваемых По Аутосомно-Рецессивному Типу (на Примере Династии Габсбургов)" [Influence on the Human Traits Transmitted According to the Autosomal-Recessive Type (on the Example of the Habsburg Dynasty)] (in Russian).
  18. ↑ Mitchell 2013, pp. 303–308.
  19. ↑ "Treating Prognathism: Ways to Correct Abnormal Jaw Alignment".
  20. ↑ "Prognathous". A Glossary of Entomological Terms. Retrieved 11 September 2019.

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