View source for Prognathism

{{Short description|Protrusion of the upper or lower human jaw}}
{{More citations needed|date=September 2018}}
{{Infobox medical condition (new) 
| name            = Prognathism 
| image           = Prognathism3.png 
| caption         = Illustration of different types
| pronounce       =  
| field           =  
| synonyms        =  Habsburg jaw (in the case of mandibular prognathism)
| symptoms        = 
| complications   = 
| onset           = 
| duration        = 
| types           = {{plain list|
* Alveolar
* Maxillary
* Mandibular or progenism}}
| causes          = Multifactorial 
| risks           = 
| diagnosis       = 
| differential    = 
| prevention      = 
| treatment       = [[Orthodontics]]; [[oral and maxillofacial surgery]]
| medication      = 
| prognosis       = 
| frequency       = {{plain list|
* Children: 0.5 to 2.0%
* Adult: 2.0 to 4.0%{{Sfn|Wolff|Wienker|Sander|1993|p=112}}}}
| deaths          = 
}}

'''Prognathism''' is a positional relationship of the [[Human mandible|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.{{clarify|reason=Should it be sagittal plane? Do both jaws normally extend ventrally beyond any line in the coronal plane?|date=December 2022}} 

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'''<ref name="Peacock Klein Mulliken Kaban 2014">{{cite journal |last1=Peacock |first1=Zachary S. |last2=Klein |first2=Katherine P. |last3=Mulliken |first3=John B. |last4=Kaban |first4=Leonard B. |title=The Habsburg Jaw-re-examined |journal=American Journal of Medical Genetics. Part A |date=September 2014 |volume=164A |issue=9 |pages=2263–2269 |doi=10.1002/ajmg.a.36639 |pmid=24942320 |s2cid=35651759 }}</ref><ref>{{cite journal |last1=Zamudio Martínez |first1=Gabriela |last2=Zamudio Martínez |first2=Adriana |title=A Royal Family Heritage: The Habsburg Jaw |journal=Facial Plastic Surgery & Aesthetic Medicine |date=2020 |volume=22 |issue=2 |pages=120–121 |doi=10.1089/fpsam.2019.29017.mar |pmid=32083497 |s2cid=211232475 }}</ref> especially when referenced with the context of its prevalence amongst historical members of the [[House of Habsburg]].<ref name="Peacock Klein Mulliken Kaban 2014"/>

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

In [[Dentistry|general dentistry]], [[oral and maxillofacial surgery]], and orthodontics, this is assessed clinically or radiographically ([[Cephalometry|cephalometrics]]). The word ''prognathism'' derives from the 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 [[tooth|teeth]] and lower teeth do not align properly.{{citation needed|date=September 2018}}

==Presentation==
[[Image:Mandibular prognathism pre-surgery.png|thumb|left|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.<ref>{{MedlinePlusEncyclopedia|003026|Prognathism}}</ref>

Prognathism is considered a disorder only if it affects [[chewing]], [[Manner of articulation|speech]] or social function as a byproduct of severely affected aesthetics of the face.{{citation needed|date=September 2018}}

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 [[malocclusion|Angle's classification]].{{citation needed|date=September 2018}}

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|date=September 2018}}

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|date=September 2018}}

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 [[malocclusion|overjet]]. When the reverse is the case, and the lower jaw extends forward beyond the upper, the condition is referred to as [[retrognathia|retrognathia (reverse overjet)]].{{citation needed|date=September 2018}}

==Classification==
===Alveolar prognathism===
[[Image:Alveolprog.jpg|thumb|175px|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.{{Sfn|Vioarsdóttir|O'Higgins|Stringer|2002|pp=211–229}}

Harmful habits such as [[thumb sucking]] or [[tongue thrust]]ing can result in or exaggerate an alveolar prognathism, causing teeth to misalign.<ref name=SinghEtAl2020>{{Cite journal |last1=Singh |first1=Tenali Sushmitha |last2=Sridevi |first2=Enuganti |last3=Sankar |first3=Avula Jogendra Sai |last4=Kakarla |first4=Pranitha |last5=Vallabaneni |first5=Siva Sai Krishna |last6=Sridhar |first6=Mukthineni |date=2020 |title=Cephalometric Assessment of Dentoskeletal Characteristics in Children with Digit-sucking Habit |journal=International Journal of Clinical Pediatric Dentistry |volume=13 |issue=3 |pages=221–224 |doi=10.5005/jp-journals-10005-1761 |issn=0974-7052 |pmc=7450188 |pmid=32904107}}</ref> Functional appliances can be used in growing children to help modify bad habits and neuro-muscular function, with the aim of correcting this condition.<ref name=SinghEtAl2020/>

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.<ref name=SahilEtAl2021>{{Cite journal |last1=Sahil |first1=Sahil |last2=Soni |first2=Sanjeev |last3=Kaur |first3=Gurpreet |date=2021-12-31 |title=Challenging Malocclusion in Orthodontics: the Open Bite |url=https://www.neliti.com/publications/426601/challenging-malocclusion-in-orthodontics-the-open-bite |journal=International Journal of Health Sciences |language=en |pages=125–134 |doi=10.53730/ijhs.v5nS2.5581 |issn=2550-6978|doi-access=free }}</ref>

===Maxillary prognathism===
In disease states, maxillary prognathism is associated with [[Cornelia de Lange syndrome]];<ref>{{cite web |title=Medical Definition of de Lange syndrome |url=https://www.medicinenet.com/de_lange_syndrome/definition.htm |website=MedicineNet }}</ref> 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|date=September 2018}}

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|date=September 2018}}

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.<ref>{{Cite web |last1=Rae |first1=Todd C. |last2=Koppe |first2=Thomas |last3=Stringer |first3=Chris B. |date=27 October 2010 |title=The Neanderthal face is not cold adapted |url=https://edisciplinas.usp.br/pluginfile.php/6200375/mod_resource/content/1/The%20neanderthal%20face%20is%20not%20cold%20adapted%20%28Rae%20et%20al%202011%29.pdf |access-date=5 May 2024 |website=Moodle USP: e-Disciplinas}}</ref>

{{Anchor|Mandibular prognathism}}

===  Mandibular prognathism (progenism) ===
[[File:Berlín DHM Leopoldo I 02.JPG|thumb|upright|[[Leopold I, Holy Roman Emperor|Leopold I]], showing progenism]]

[[Mandible|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]].{{Sfn|Vilas|Ceballos|Al-Soufi|González-García|2019|pp=563-571}} 

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.<ref>{{Cite journal |last1=Kulkarni |first1=Shilpa Devdatt |last2=Bhad |first2=Wasundhara A. |last3=Doshi |first3=Umal H. |date=2020 |title=Association Between Mandibular Prognathism and MATRILIN-1 Gene in Central India Population: A Cross-sectional Study |journal=Journal of Indian Orthodontic Society |volume=55 |issue=1 |pages=28–32 |doi=10.1177/0301574220956421 |doi-access=free }}</ref>

In brachycephalic or flat-faced dogs, like [[shih tzu]]s and [[Boxer (dog)|boxers]], it can lead to problems such as underbite.{{Sfn|Beuchat|2015}}

In humans, it results in a condition sometimes called ''lantern jaw'', reportedly derived from 15th century [[Lantern|horn lanterns]], which had convex sides.<ref>{{OMIM|176700|PROGNATHISM, MANDIBULAR}}</ref>{{Efn|The ''[[Oxford English Dictionary|OED]]'' uses a slightly different definition: "long thin jaws, giving a hollow appearance to the cheek".<ref>{{OED|lantern jaw|id=105665}}</ref>}} Traits such as these were often exaggerated by inbreeding, and can be traced within specific families.{{Sfn|Vilas|Ceballos|Al-Soufi|González-García|2019|pp=563-571}}

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.{{Sfn|Vilas|Ceballos|Al-Soufi|González-García|2019}} The process of portrait-mapping has provided tools for [[geneticist]]s and [[Pedigree chart|pedigree]] analysis; most instances are considered [[polygene|polygenic]],{{Sfn|Wolff|Wienker|Sander|1993|pp=112–116}} but a number of researchers believe that this trait is transmitted through an autosomal recessive type of inheritance.<ref name="Безуглый 2020">{{cite web |last1=Безуглый |first1=Т. А. |title=Влияние На Человека Признаков, Передаваемых По Аутосомно-Рецессивному Типу (на Примере Династии Габсбургов) |trans-title=Influence on the Human Traits Transmitted According to the Autosomal-Recessive Type (on the Example of the Habsburg Dynasty) |date=2020 |url=https://www.elibrary.ru/item.asp?id=44270977 |language=ru }}</ref>{{Sfn|Vilas|Ceballos|Al-Soufi|González-García|2019}}

Allegedly introduced into the family by a [[Cymburgis of Masovia|member]] of the [[Piast dynasty]], it is clearly visible on family tomb sculptures in [[St. John's Archcathedral, Warsaw|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,{{Sfn|Mitchell|2013|pp=303-308}} due to the high number of [[consanguineous]] marriages in the dynasty preceding his birth.<ref name="Безуглый 2020"/>{{Sfn|Vilas|Ceballos|Al-Soufi|González-García|2019}}

{{multiple image
| align             = center
| image1            = Charles II.jpg
| width1            = 150
| caption1          = [[Charles II of Spain]] showing '''Habsburg jaw''', a severe type of mandibular prognathism
| image2            = Vlad Ţepeş, the Impaler, Prince of Wallachia (1456-1462) (died 1477).jpg
| width2            = 150
| caption2          = [[Vlad III]] of Wallachia, showing progenism
| image3            = Arveprins Frederik (Juel).JPG
| width3            = 150
| caption3          = [[Frederick, Hereditary Prince of Denmark|Frederick, regent of Denmark-Norway]], showing progenism
| image4            = Pedro II of Brazil 1851 edit.png
| width4            = 150
| caption4          = [[Pedro II of Brazil]], showing progenism. His mother was Archduchess [[Maria Leopoldina of Austria]], a member of the [[House of Habsburg-Lorraine]] by birth.
| footer            = 
}}

==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 [[Dental braces|braces]], removal of teeth, or a [[mouthguard]].<ref>{{cite web |url=https://www.colgate.com/en-us/oral-health/developmental-disabilities/treating-prognathism-ways-to-correct-abnormal-jaw-alignment |title = Treating Prognathism: Ways to Correct Abnormal Jaw Alignment}}</ref>

==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.<ref>{{cite web |title=Prognathous |url=https://www.earthlife.net/insects/glossary.html#16 |website=A Glossary of Entomological Terms |access-date=11 September 2019}}</ref>

==See also==
* [[Dental pathology]]

== Footnotes ==
{{notelist}}

== References ==
{{Reflist}}

== General and cited sources ==
* {{Cite web |last1=Beuchat |first1=Carol|date=12 March 2015 |title=Why all the fuss about inbreeding? |url=https://www.instituteofcaninebiology.org/blog/why-all-the-fuss-about-inbreeding-or-why-do-we-have-so-many-genetic-disorders-in-dogs |publisher=Institute of Canine Biology |access-date=16 April 2020}}
* {{Cite thesis |last1=Mitchell |first1=Sylvia Z |date=May 2013 |title=Mariana of Austria and Imperial Spain: Court, Dynastic, and International Politics in Seventeenth-Century Europe |url=https://scholarship.miami.edu/permalink/01UOML_INST/1grrnr5/alma991031447870202976 |type=Ph.D. |location=Coral Gables, Florida |publisher=University of Miami}}
* {{Cite journal |last1=Vilas |first1=Román |last2=Ceballos |first2=Francisco C. |last3=Al-Soufi |first3=Laila |last4=González-García |first4=Raúl |last5=Moreno |first5=Carlos |last6=Moreno |first6=Manuel |last7=Villanueva |first7=Laura |last8=Ruiz |first8=Luis |last9=Mateos |first9=Jesús |last10=González |first10=David |last11=Ruiz |first11=Jennifer |last12=Cinza |first12=Aitor |last13=Monje |first13=Florencio |last14=Álvarez |first14=Gonzalo |title=Is the 'Habsburg jaw' related to inbreeding? |journal=Annals of Human Biology |date=17 November 2019 |volume=46 |issue=7–8 |pages=553–561 |doi=10.1080/03014460.2019.1687752 |pmid=31786955 |s2cid=208536371 |url=https://figshare.com/articles/dataset/Is_the_Habsburg_jaw_related_to_inbreeding_/11302394 |url-access=subscription }}
* {{Cite journal |last1=Vioarsdóttir|first1=US|last2=O'Higgins|first2=O|last3=Stringer|first3=C |title=A geometric morphometric study of regional differences in the ontogeny of the modern human facial skeleton |journal=J. Anat. |volume=201 |issue=3 |year=2002 |pages=211–229|pmid=12363273 |doi=10.1046/j.1469-7580.2002.00092.x |pmc=1570912}}
* {{Cite journal |last1=Wolff |first1=G |last2=Wienker |first2=T F |last3=Sander |first3=H |title=On the genetics of mandibular prognathism: analysis of large European noble families. |journal=Journal of Medical Genetics |date=1 February 1993 |volume=30 |issue=2 |pages=112–116 |doi=10.1136/jmg.30.2.112 |pmid=8445614 |pmc=1016265}}

== External links ==
* {{Wiktionary-inline}}

{{Medical resources
|  DiseasesDB     = 29354 
|  ICD10          = {{ICD10|M26.10}} 
|  ICD9           = {{ICD9|524.10}} 
|  ICDO           = 
|  OMIM           = 
|  MedlinePlus    = 003026 
|  eMedicineSubj  = 
|  eMedicineTopic = 
|  MeshID         = D011378 
}}
{{Dentofacial anomalies and jaw disease}}

[[Category:Biological anthropology]]
[[Category:Facial features]]
[[Category:House of Habsburg]]
[[Category:Jaw disorders]]
[[Category:Paleoanthropology]]

[[pt:Prognatismo]]