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Blair 1907
Ko
Kazanjian 1951
Obwegeser 1968
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abce
Scholossman 1922
stečka 1926
Fig. 10.1 Development of ostetomy approaches in mandibular surgery over time. Evolution of the mandibular
osteotomies. (a) Blair 1907. (b) Schlössmann-PerthesKazanjian 1922–1951. (c) Schuchardt 1954. (d)
Obwegeser 1955. (e) Obwegeser 1957. (f) Dal Pont 1958.
Perthes 1924
Schuchardt 1954
of maxillofacial surgery. He trained Richard
Trauner, Heinrich Köle, and Hugo Obwegeser
and is also famous for operating Sigmund Freud
who suffered from oral cancer [1]. The rst
bimaxillary surgery to correct malocclusion was
described by Heinrich Köle in 1959. He treated a
patient with bimaxillary protrusion pattern by
performing subapical osteotomies in both jaws
[1, 2, 6].
Although the described techniques were progressive at their time, they were commonly associated with unacceptable complications like
relapse, open bite, pseudoarthrosis, and mandibular and facial nerve injury [7]. In the words of
Hugo Obwegeser, orthognathic surgery consisted
of a series of unsatisfying procedures primarily
to correct prognathism [7].
In 1952, Richard Trauner, chief of the maxillofacial department in Graz, asked Hugo
Obwegeser to follow up their cases of Kostecka
operations. Obwegeser detected around 50% of
unacceptable complications like described
above. According to Obwegeser, Richard
Trauner assumed that the main issue was inadequate bony union because of the too small area
of contacting bone surfaces of the bone segments [7]. Searching for a technique that would
allow for broader contacting bone surfaces to
improve ossication of the segments [7],
Obwegeser was gaining for an osteotomy with
Obwegeser 1955 Obwegeser 1957
(g) Obwegeser 1968. (Obwegeser HL. Orthognathic
Surgery and a Tale of How Three Procedures Came to Be:
A Letter to the Next Generations of Surgeons. Clin Plast
Surg. 2007. https://doi.org/10.1016/j.cps.2007.05.014)
broad bone contact that could be performed
without an external skin incision [7]. However,
in these days, an intraoral approach was considered unconceivable because of the risk of infection. Based on his experience in trauma surgery
revealing only minimal complications in mandibular fractures that were treated immediately
after the accident, Obwegeser supposed surgical
procedure to be nothing more than a controlled
trauma expecting it to heal in the same way.
Studying a cadaver mandible, the idea of the
bilateral sagittal split osteotomy came to his
mind [7].
Obwegeser’s rst successful sagittal split case
was a prognathic 24-year-old woman. He operated her together with his boss Richard Trauner
on April 22, 1953. Obwegeser started on the left
side and successfully performed his idea of a sagittal split. The other side was operated by Richard
Trauner who performed an inverted-L osteotomy.
The bone segments were stabilized by circumferential wires, and the patient was put under rigid
intermaxillary xation for 6weeks. The patient
recovered well from the operation and even fully
regained sensory function within 1year post-op.
With this case, the transoral sagittal split osteotomy was born. Obwegeser and Trauner published
their concept in 1955, and it would become the
most popular technique for the correction of
mandibular deformities [1, 7] (Fig.10.2).
Dal Pont 1958
g
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Fig. 10.2 Detailed description of the mandibular saggital
split osteotomy. Illustration from the publication of the
sagittal splitting procedure in the 1957 English article by
Trauner and Obwegeser. (Obwegeser HL. Orthognathic
The Italian orthodontist Giorgio Dal Pont
was a visiting trainee in Zürich. Watching
Obwegeser performing a sagittal split osteotomy, he came up with the idea of changing the
lateral corticotomy from the horizontal ramus to
the vertical body, and it worked well. After
returning to Italy, Dal Pont published his modication in Italian and later in American literature before Obwegeser was able to do it [7, 8]. It
might be one of the most famous curiosities in
the history of orthognathic surgery, that, at least
according to Obwegeser, Dal Pont never performed the operation by himself and did not cite
and did not even mention Obwegeser as a coauthor [7].
The American maxillofacial surgeon Ervin
E. Hunsuck modied Obwegeser’s sagittal split
osteotomy. He limited the extent of the medial
horizontal osteotomy at the level of the lingula
just past the entrance of the inferior alveolar
nerve [1, 9]. Later on, Jeffrey C.Posnick came up
with another modication by putting this limited
osteotomy even lower inferior to the lingula [2].
The intention of these modications was to
Surgery and a Tale of How Three Procedures Came to Be:
A Letter to the Next Generations of Surgeons. Clin Plast
Surg. 2007. https://doi.org/10.1016/j.cps.2007.05.014)
reduce the risk of a bad split, and especially
Hunsuck’s modication is nowadays widely
used.
Genioplasty
Until the 1950s, microgenia was treated with
onlay techniques by bone and cartilage grafts or
alloplastic materials through an extraoral submental approach [2]. However, these procedures
were unsatisfying because of complications like
asymmetric bone resorption, infection, and dislocation of alloplastic materials. The concept of a
sliding genioplasty was rstly described by the
German surgeon Hofer on a cadaver via an extraoral approach in 1942 [10]. Obwegeser and
Trauner took up the idea and published the rst
sliding genioplasty via an intraoral approach in a
patient in 1955 [1, 2, 7, 11]. Genioplasty became
a standard procedure for prole correction and is
nowadays often performed in combination with
bimaxillary surgery to gain an ideal aesthetic and
functional result. In 2009, Albino Triaca pub-
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lished his chin wing osteotomy, which also allows
correction of the mandibular plane and the intergonial angle [12, 13].
Maxillary Surgery
The techniques to move the maxilla in ideal position were established years after the mandibular
procedures. Lots of patients with a craniofacial
deformity, who mainly suffered from midface
hypoplasia and retromaxilla, were treated with
mandibular setback. Although they gained a
correct occlusion, the aesthetic problem of a at
midface was not solved [7].
Surgical mobilization of the maxilla was rst
reported by Langenbeck in 1859 and by Cheever
in 1867in order to gain access to epipharynx and
to treat skull base tumors [1, 2, 7]. Techniques to
correct craniofacial deformities were described
decades later. Martin Wassmund performed the
rst detachment of the maxilla in order to treat an
anterior open bite in 1927 [1, 2, 7]. After osteotomy of the maxilla, he used elastics to close the
open bite. However, he did not separate the maxilla from the pterygoid processes. Georg
Axhausen rst published the successful repositioning of the maxilla in trauma and cleft cases
after complete osteotomy of the maxilla with
separation of the pterygoid processes in the 1930s
[1, 2, 7]. In 1942, Schuchardt detached the maxilla in a post-traumatic war case. In a second
operation, he separated the maxilla from the pterygoid processes and used weight traction to reposition the dislocated maxilla [1, 2, 7].
However, maxillary osteotomy with separation from the pterygoid processes to gain anterior
advancement did not become clinical routine
until the 1960s. Sir Harold Gillies used horizontal vestibular incisions to approach the maxilla.
He corrected maxillary deformities in cleft
patients by maxillary osteotomy and a greenstick
fracture at the pterygoid processes in the early
1950s [1, 2, 7]. Professor Eduard Schmid from
Marienhospital Stuttgart in Germany reported
maxillary osteotomies for the correction of posterior crossbites [2, 14]. Professor Schmid was
world famous at this time for inventing numerous
plastic and reconstructive surgical procedures,
and Hugo Obwegeser spent part of his training
with him at Marienhospital Stuttgart.
In 1964, Hugo Obwegeser was confronted
with a complex midface trauma case [7]. An
18-year-old man suffered from a car accident
6weeks before presenting severe anterior open
bite and a posterior displaced maxilla with a
palatal split [7]. His vestibular mucosa was
scarred circumferentially, and he had multiple
oronasal stulas [7]. Therefore, Obwegeser
could not use his usual approach with vertical
vestibular incisions in order to preserve blood
supply [7]. Instead, he had to use a circumferential vestibular approach through the old scars
[7]. Reposition of the displaced maxilla into
correct position was performed by a LeFort I
osteotomy with a palatal split of the old fracture
[7]. Obwegeser raised the nasal mucosa,
detached the septum [7], cut the lateral nasal
walls, and separated the maxilla from the pterygoid processes [7]. When simply pressing rmly
on the anterior maxilla with his ngers, the
maxilla separated easily [7]. This maneuver was
later called the “downfracture technique” [7].
He then intentionally recreated the palatal fracture and used curved osteotomes to fully mobilize the two maxilla segments [7]. After that, he
could move the maxillary segments signicantly
anterior and in the correct position to reestablish
occlusion [7]. Wire xation was used to secure
the maxilla segments [1, 2, 7]. Standard LeFort
I osteotomy that is nowadays routinely used in
orthognathic surgery was born [7].
The Biological Basis
forOrthognathic Surgery
Before William H.Bell investigated the biological basis for facial osteotomies, there was no biological foundation that supported these
considerably unpredictable and risky procedures
[2]. With his extensive microangiographic and
histologic studies in rabbits and monkeys,
William H.Bell established the biological basis
for orthognathic surgery [2]. He investigated
healing and revascularization of the osteotomy
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129
gap and studied the blood vessels necessary to
maintain blood supply to the bone segments and
teeth [2]. In 1969, William H.Bell published his
famous work and concluded, “no single blood
vessel, such as the incisive canal or greater palatine arteries, is essential to maintenance of circulation to the anterior maxillary fragment” [2].
Later, Bell conducted similar experiments for
almost every orthognathic procedure, and his
research is considered the biological basis of
modern orthognathic surgery. Before his work,
these operations were only rarely performed
because of the fear over the viability of bone
segments and teeth [2]. After establishing safety
and predictability of the techniques in Bell’s laboratory, orthognathic surgery gained great popularity [2].
Bimaxillary Surgery
The rst bimaxillary orthognathic surgery was
performed by Heinrich Köle in 1959 [1, 2, 6]. He
treated a patient with bimaxillary protrusion with
subapical osteotomies in the maxilla and the
mandible [1, 2, 6]. As there are many patients in
which moving a single jaw with establishing correct occlusion does not lead to a satisfying aesthetic result, Obwegeser later on promoted the
concept of bimaxillary surgery. In 1969, he performed the rst simultaneous sagittal splitting of
the mandible and a LeFort I osteotomy in a
patient [7]. Based on cephalometric radiograph
analysis and clinical and aesthetic judgment, the
maxillomandibular complex was moved in the
planned position. Obwegeser xed the maxilla
and the mandible in place with bone grafts and
wires, and after the operation, the patients were
kept in IMF for 6weeks [7]. In 1968, Hans Luhr
invented the concept of modern osteosynthesis
with miniplate and screw xation [2, 7, 15]. His
work led to another revolution of orthognathic
surgery increasing osteotomy stability and limiting the need for extended intermaxillary xation
[2, 7, 15].
Following these milestones, orthognathic surgery became a subspeciality on its own and
quickly spread around the world. Orthognathic
surgery gained great popularity, and bimaxillary
surgery became a safe and standardized procedure, which is nowadays regularly performed in
order to improve patient’s occlusion and facial
aesthetics.
Craniofacial Surgery
andDistraction Osteogenesis
The history of orthognathic surgery is closely
related to the development of craniofacial surgery. Already in 1950, Harold Gillies published
the rst LeFort III osteotomy, but because of the
high risk of the operation, he had recommended
to others “to never do it” [1, 2, 16]. Later in the
1960s, Paul Tessier performed LeFort III osteotomies to treat children with Apert and Crouzon
syndrome [1, 2, 17]. During the late 1960 and
1970s, Paul Tessier developed lots of surgical
procedures for the correction of craniofacial
deformities, and due to his great contribution, he
is considered the father of craniofacial surgery [1,
2, 17].
Cesar Guerrero from Venezuela was heavily
inuenced by William H. Bell’s biological
research. He was the rst to apply the concept of
distraction osteogenesis to orthognathic surgery.
In 1995, Guerrero performed the rst transoral
mandibular distraction osteogenesis to lengthen
the lower jaw [2, 18]. Based on his work, distraction osteogenesis gained great popularity for
lengthening maxilla and mandible in orthognathic procedures [2].
Orthognathic Surgery Today
andintheFuture
Another milestone of orthognathic surgery was
the application of virtual treatment planning and
CAD/CAM technology. Gwen Swennen from
Belgium and Jaime Gateno together with James
Xia from Texas invented the concept of 3D imaging and virtual surgical planning in combination
with 3D-printed interocclusal splints to transfer
the virtual plan into reality [1, 19–23]. Nowadays,
orthognathic surgery is routinely performed with
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T. Fillies and T. Seier
the help of virtual surgical planning, CAD/CAM
interocclusal splints, cutting guides, and patientspecic implants. Minimal invasive techniques
and modern anesthesiology decreased postoperative downtime of patients, and bimaxillary surgery is nowadays even offered in an outpatient
setting.
A lot has changed since the courageous efforts
of the “fathers of orthognathic surgery” in the
mid of the nineteenth and the early twentieth centuries. However, ongoing research and invention
will lead to new paradigm shifts. Maybe augmented reality, articial intelligence, and robotic
surgery will catapult orthognathic surgery in the
next era in the near future.
References
1. Bell RB.A history of orthognathic surgery in North
America. J Oral Maxillofac Surg. 2018;76(12):2466–
81. https://doi.org/10.1016/j.joms.2018.09.006.
2. Posnick JC.Orthognathic surgery: principles and practice. 2013. https://doi.org/10.1016/C2011- 1- 04193- 0.
3. Hullihen SP.Case of elongation of the under jaw and
distortion of the face and neck, caused by a burn, successfully treated. Am J Dent Sci. 1849;9:157.
4. Haeseker B, Veltheer W. The signicance of
Eiselsberg and the Viennese school of surgery for
the development of reconstructive surgery in Europe.
Br J Plast Surg. 1992;45(3):246–50. https://doi.
org/10.1016/0007- 1226(92)90087- E.
5. Blair VP.Report of a case of double resection for the
correction of protrusion of the mandible. Dent Cosm.
1906;48:817–20.
6. Köle H. Surgical operations on the alveolar ridge
to correct occlusal abnormalities. Oral Surg Oral
Med Oral Pathol. 1959;12(5):515–29. https://doi.
org/10.1016/0030- 4220(59)90153- 7.
7. Obwegeser HL.Orthognathic surgery and a tale of how
three procedures came to be: a letter to the next generations of surgeons. Clin Plast Surg. 2007;34:331–55.
https://doi.org/10.1016/j.cps.2007.05.014.
8. Dal Pont G.Retromolar osteotomy for the correction
of prognathism. J Oral Surg Anesth Hosp Dent Serv.
1961;19:42–7.
9. Hunsuck EE. A modied intraoral sagittal splitting
technic for correction of mandibular prognathism. J
Oral Surg. 1968;26:529.
10. Hofer O.Operation der Prognathie und Mikrogenie.
Dtsch Zahn- Mund- u Kieferheilk. 1942;9:121.
11. Obwegeser H, Trauner R. Zur Operationstechnik
bei der Progenie und anderen Unterkieferanomalien.
Dtsch Zahn Mund Kieferheilkd. 1955;23:1.
12. Triaca A, Brusco D, Guijarro-Martínez R.Chin wing
osteotomy for the correction of hyper-divergent skeletal class III deformity: technical modication. Br
J Oral Maxillofac Surg. 2015;53:775. https://doi.
org/10.1016/j.bjoms.2015.05.015.
13. Triaca A, Minoretti R, Saulacic N. Mandibula wing
osteotomy for correction of the mandibular plane: a
case report. Br J Oral Maxillofac Surg. 2010;48:182.
https://doi.org/10.1016/j.bjoms.2009.08.011.
14. Schmid E.Zur Wiederherstellung des Mittelgeisichtes
nach Entwicklungsstörungen und Defekten des
knöchernen Unterbaues. Fortschr Kiefer Gesichtschir.
1956;II:240–3.
15. Luhr HG. Zur stabilen Osteosynthese bei
Unterkieferfrakturen. Dtsch Zahnarztl Z. 1968;23:754.
16. Gillies H, Harrison SH.Operative correction by osteotomy of recessed malar maxillary compound in case
of oxycephaly. Br J Plast Surg. 1950;3:102.
17. Tessier P. Osteotomies totales de la face: syndrome
de Crouzon, syndrome d’Apert: oxycephalies,
scaphocephalies, turricephalies. Ann Chir Plast.
1967;12:273–86.
18. Guerrero C, Bell WH, Flores A, et al. Distraccion
osteogenica mandibular intraoral. Odontol Dia.
1995;11:116.
19. Swennen GRJ, Mollemans W, Schutyser F. Threedimensional treatment planning of orthognathic surgery in the era of virtual imaging. J Oral Maxillofac
Surg. 2009;67:2080–92. https://doi.org/10.1016/j.
joms.2009.06.007.
20. Swennen GRJ. 3D virtual treatment planning of
orthognathic surgery. In: 3D virtual treatment planning of orthognathic surgery: a step-by-step approach
for orthodontists and surgeons; 2016. https://doi.
org/10.1007/978- 3- 662- 47389- 4_3.
21. Xia JJ, Gateno J, Teichgraeber JF, etal. Algorithm for
planning a double-jaw orthognathic surgery using a
computer-aided surgical simulation (CASS) protocol. Part 1: planning sequence. Int J Oral Maxillofac
Surg. 2015;44:1431. https://doi.org/10.1016/j.
ijom.2015.06.006.
22. Gateno J, Xia J, Teichgraeber JF, Rosen A.A new
technique for the creation of a computerized composite skull model. J Oral Maxillofac Surg. 2003;61:222.
https://doi.org/10.1053/joms.2003.50033.
23. Xia JJ, Gateno J, Teichgraeber JF, et al. Algorithm
for planning a double-jaw orthognathic surgery using
a computer-aided surgical simulation (CASS) protocol. Part 2: three-dimensional cephalometry. Int
J Oral Maxillofac Surg. 2015;44:1441. https://doi.
org/10.1016/j.ijom.2015.06.007.
Classication ofJaw
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Malformations (Dysgnathias)
inCraniofacially Malformed
Patients
UlrichMeyer
11
Introduction
Malocclusion is a term that focuses on the occlusal aspect of dental and skeletal malformations.
Malocclusion is one effect of alterations in skull,
jaw, or teeth geometry. Such situations are present in individuals worldwide, resulting in compromised function and esthetics. This is caused
by a growth disturbance during fetal or post-fetal
development. Patients with skeletal malocclusion
may suffer from dental deformities, bruxism,
teeth crowding, trismus, mastication difculties,
breathing obstruction, and digestion disturbance
if the problem is left untreated. The presence and
extent of such dysgnathic situations can be seen
as isolated phenotypes or as part of syndromes.
Understanding the etiological factors contributing to the variation in craniofacial morphology
associated with precise nomenclature of geometric anatomical alterations towards the normal
anatomy is the key to classication approaches in
craniofacially diseased patients [1]. Advances in
craniofacial, jaw, and dental phenotyping,
through three-dimensional geometric data acquisition by modern imaging techniques, are one
prerequisite for a more precise classication of
such patients.
U. Meyer (*)
Center for Jaw-, Face- and Skull Surgery,
Münster, Germany
e-mail: praxis@mkg-muenster.de
To date, none of the existing databases contains comprehensive dentofacial data for malocclusions (dysgnathias). Therefore, cause-effect
correlation studies of malocclusion are greatly
needed as the knowledge gained from them will
aid in our understanding of the mechanisms
responsible for human malocclusions through
craniofacial anomalies.
Classication Systems
Malocclusion combined with or without jaw
deformities is one of the most prevalent developmental anomalies of craniofacial structure.
Classication systems were introduced by different persons or groups (clinicians, researchers,
healthcare providers) in order to clarify and
dene clinical situations, help to standardize clinical treatments, and compare treatment outcomes.
Most classication schemes were introduced by
dentists or orthodontists [2], some by oral or
maxillofacial surgeons, and others by physicians
working in the healthcare-providing system.
Classication of malocclusion was rst introduced by Angle. Dr. Edward H.Angle is considered one of the pioneers in developing the eld of
orthodontics. Angle’s classication in 1899 of
occlusion was an important step for formal diagnosis of malocclusion cases towards improving
therapeutic approaches. The classication is
based on the position of lower molar towards the
© Springer Nature Switzerland AG 2023
U. Meyer (ed.), Fundamentals of Craniofacial Malformations,
https://doi.org/10.1007/978-3-031-28069-6_11
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U. Meyer
upper molar and whether it is distally or mesially
positioned. However, the distinction between
dental and skeletal malocclusion is not included
in his scheme. Later, various classication systems and dentofacial analyses were introduced in
clinical practice. Most of them used the term dentofacial deformities. An anatomical intact skull
base is a prerequisite for most of these classication and analysis approaches.
In the analysis of the clinical term dentofacial
deformities, two terms must be dened.
The rst word dentofacial is itself a compound
word made by the fusion of two words dental
(dento) and face (-facial), meaning of the teeth
and face. Based on the literal meaning of the
term, one may assume that it embodies all the
deformities that affect the teeth and the face. In
practice, however, this is not the case [3].
The denition of the second word deformity is
more precise, stating that an object has an abnormal form, disgurement, or loss of the natural
arrangement.
In contrast to the orthodontic based classication of dentofacial deformities, their diagnostics,
and the proper treatment protocols, a medical
based classication system was introduced to
dene the extent (and try to assess and estimate
the costs) for the medical (surgical) treatment of
such patients. In a lot of countries (like the United
States), the most widely used classication system for jaw deformities in medicine is the one
provided by the Centers for Health Statistics (in
the United States, e.g., the Centers for Medicare
& Medicaid Services and the National Center for
Health Statistics) [4]. This classication is part of
the International Classication of Diseases,
Clinical Modication (ICD-CM), a taxonomy
scheme that is based on the World Health
Organization’s International Classication of
Diseases (ICD) [5], the world’s standard diagnostic tool for epidemiology, health management,
and clinical care. The last iteration of ICD-CM,
version 10, sorts jaw deformities according to
geometry into three groups: anomalies of jaw
size, anomalies of jaw-cranial base relationship,
or unspecied.
Gateno’s New Classication System
Gateno and colleagues [3] analyzed in their paper
A geometric classication of jaw geometries that
the ICD-CM classication as well as most orthodontic based analysis and classication systems
are incomplete and disjointed. They developed a
much better classication system. Especially,
they introduced a much more precise geometric
based nomenclature of deviations from normal.
In the following, we refer to their elaborated system and extend it towards craniofacially diseased
patients.
Gateno and colleagues pronounce in their
impressive analysis of craniofacial deformation
the following:
The denition of deformity is having an
abnormal form, disgurement, or loss of the natural arrangement. To diagnose a deformity, they
assess an anatomical unit (Fig.11.1) and determines if its conguration (form) is normal or
abnormal. Instead of other classication systems,
their modern approach to the evaluation of form
sees an anatomical unit (e.g., the mandible) as a
geometric object. As any other geometric object,
an anatomic unit is seen as having basic attributes: size, position, orientation, shape, and completeness (Table11.1). Size refers to how large or
how small something is. Position refers to its
location in space (anterior-posterior, mediallateral, cranial-caudal). Orientation refers to tilt.
Shape refers to gure. Finally, completeness
refers to the wholeness. Besides having these
attributes, some anatomical units, such as jaws,
also have bilateral symmetry. This means that the
objects can be divided into two halves, each part
being the mirror image of the other. In summary,
the jaws have six geometric attributes, which
include the ve basics plus symmetry.
Their scheme rst classies jaw deformities as
either osseous or dental. Osseous deformities
affect the jawbones, while dental deformities
affect the teeth.
Jaw deformities are classied according to the
attribute they affect. Deformities of size occur
when a jaw is too big or too small. The term
Craniofacial deformity
geometric object
11 Classication ofJaw Malformations (Dysgnathias) inCraniofacially Malformed Patients
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Fig. 11.1 Anatomical
object depiction
133
1
2
2
4
6
Table 11.1 Nomenclature of jaw geometry
Geometric
object attribute Meaning Terminology
Size Small–big Metric size
Position Location in
space
Orientation Tilt Angulation
Shape Figure Anatomy, phenotype
Completeness Wholeness Defect, atrophy
hyperplasia indicates pathological enlargement,
and hypoplasia failure to attain normal size.
Micrognathia is a synonym for mandibular hypoplasia and macrognathia for mandibular hyperplasia. The terms macrogenia and microgenia
also refer to size, macrogenia indicating large
chin and microgenia a small one. Abnormal jaw
positions occur in all cardinal directions.
Prognathism and retrognathism are deformities
characterized by an abnormal anteroposterior
position. By convention, the anteroposterior position is assessed in relation to the cranial base. In
prognathism, a jaw is too far forward, while in
retrognathism, it is too far back. In the transverse
direction, a jaw can be displaced away from the
sagittal plane in either direction. This deformity
is called laterognathia. Vertically, a jaw can be
too far down or too far up. In excessive downward displacement, a jaw is too far down. In
Anterior–posterior;
medial–lateral;
cranial–caudal
anatomical unit
2
3
5
-cranial vault 1
-skull base 2
-orbit 3
-zygoma4
-maxilla 5
-mandible6
-chin7
7
insufcient downward displacement, it is too far
up. Malrotations occur when a jaw is abnormally
oriented. We classify malrotations according to
the axis on which the abnormal rotation occurs. A
jaw that is abnormally rotated around the transverse facial axis has a pitch malrotation. A jaw
that is abnormally rotated around the anteroposterior axis has a roll malrotation, a condition that
is also known as canting. A maxilla or a mandible
that is abnormally rotated around the vertical axis
has a yaw malrotation. Shape refers to gure. A
jaw with abnormal gure is said to be distorted.
The human face has reection symmetry
around one plane, the sagittal. For facial symmetry to exist, two conditions must be met. First,
each of the units that compose the face must itself
be symmetrical—a condition called object symmetry. Second, each of the units must be symmetrically aligned to the sagittal plane—a
condition called symmetric alignment. Jaws can
have deformities of symmetry either because of
object asymmetry or because of misalignment.
The terms mandibular asymmetry and maxillary
asymmetry refer to abnormalities in object symmetry. The term asymmetric alignment denotes
abnormal alignment that causes asymmetry. The
term completeness refers to the wholeness of the
jaw. A jaw can be incomplete because one of its
processes (apophysis) never developed. An
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U. Meyer
example is agenesis of the condylar process of
the mandible seen in hemifacial microsomia. It
can also be incomplete because some of its
embryologic processes failed to fuse (cleft), or
because it acquired a defect.
As stated above, jaw deformities can also
affect the teeth. Gateno’s classication scheme
only considers dental deformities that engender
malocclusion (Table 11.2). Malocclusion can
result when one or more teeth are disarranged in
their dental arch. Alternatively, it can result when
the upper and lower dental arches are not coordinated. Within a dental arch, a deformity may
affect the alignment, the leveling, or the spacing
of teeth. Alignment refers to the arrangement of
teeth in an arch. In ideal alignment, the incisal
edges of the incisors and the buccal-cuspal ridges
of the canines, premolars, and molars form an
arch. Misalignment can happen because of dental
displacement, dental tipping, or dental rotations.
In displacement, a tooth is moved outside the
arch. In tipping, a tooth is abnormally inclined. In
rotations, a tooth is misaligned because of abnormal rotation around its long axis.
Leveling refers to the vertical arrangement of
teeth. Abnormal leveling can affect a single tooth
or the whole arch. For this assessment, one measures the vertical position of the teeth in relation
to their occlusal plane. In other words, one measures the vertical positions of the lower teeth in
relation to the mandibular occlusal plane and the
vertical positions of the upper teeth in relation to
the maxillary occlusal plane. An individual tooth
is in infraocclusion or supraocclusion when it is
located below or above its ascribed occlusal
plane. For a whole dental arch, once judge’s dental leveling by gauging the curve of Spee. From
the central incisor backward to the last molar, the
cusps of all teeth should inscribe either a at
plane or a curved plane with slightly upward concavity. Dental deformity can create a deep or a
reverse curve of Spee. A curve of Spee is deep
when the cusps of the teeth trace a plane with a
sharp upward curvature. The curve of Spee is
reversed when the curvature of the plane has
downward concavity.
Within a dental arch, the teeth should be normally spaced: adjacent teeth should touch without crowding each other. Spacing is abnormal
when diastemas are present or when the arch cannot accommodate the teeth. The rst condition is
excessive dental spacing and the second dental
crowding.
As stated above, dental deformities can also
occur when the upper and lower arches are not
harmonized. For normal occlusion to occur, it is
not enough for the upper and lower teeth to be
normally arranged in an arch. The upper and
lower dental arches must also be coordinated, in
position, in shape, and in tooth size. Discordant
dental arch positions cause malocclusion. This
lack of concordance can occur in all the cardinal
directions: anteroposterior, vertical, and transverse. We appraise the anteroposterior occlusal
relationships at three different sites. These are at
the rst molar, canine, and central incisors. In
this appraisal, the frame of reference is the upper
dentition.
Position discordance between the upper and
lower dental arches also occurs in the vertical
Table 11.2 Nomenclature of dental and dental arch geometry
1. Teeth disarranged in dental arch
Alignment Dental displacement Dental tipping Dental rotation
Leveling Infraocclusion Supraocclusion
Spacing Dental spacing Dental crowding Diastema
2. Dental arches discoordinated
Position Dental displacement Dental tipping Dental rotation
Shape Infraocclusion Supraocclusion
Tooth size Dental spacing Dental crowding Diastema
11 Classication ofJaw Malformations (Dysgnathias) inCraniofacially Malformed Patients
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direction. Absence of vertical overlap between
the upper and lower teeth produces an open bite.
It can be anterior or posterior. Excessive vertical
overlap of the anterior teeth results in deep bite.
Excessive vertical overlap of the posterior teeth
results in posterior bite collapse. The last condition can only occur when posterior teeth are
missing, and the remaining teeth have no opposing occlusion. Finally, discordance between the
maxillary and mandibular dental arches can also
occur in the transverse dimension. Normally, the
buccal cusps of the maxillary posterior teeth lay
laterally to the buccal cusps of the mandibular
teeth. When the reverse occurs, we encounter a
posterior crossbite. In extreme cases, all the
lower teeth can be inside the upper, a condition
known as Brodie bite. Reversely, the upper teeth
can be inside the lower, a condition known as
scissor bite. As mentioned before, the upper and
lower arches can also occlude abnormally
because they have different shapes. For example,
a “U”-shaped lower arch does not t a “V”-shaped
upper. The lack of shape congruency between the
upper and lower teeth results in arch shape discordance. Finally, to get good dental interdigitation in class I occlusion, the width (mesio-distal
size) of the lower teeth must be proportional to
the width of the upper teeth. When this proportionality is absent, the dental arches have a tooth
size discrepancy.
Gateno and colleagues introduced a precise
and accurate nomenclature of jaw deformities.
They replaced the terms vertical-maxillary-
excess and vertical-maxillary-deciency. As the
terms excess and deciency denote size, yet clinically, one establishes vertical “excess” or vertical “deciency” by measuring the distance
between the central incisors and the lip. They
stated precisely that metric measures position,
not size. They created new terms: excessive
downward displacement and insufcient downward displacement, which harmonize with geometry. They also adopted the term malrotation for
deformities of orientation. Roll malrotation is
substituted for cant, canting, occlusal cant, and
maxillary cant. Yaw malrotation is substituted for
yaw. And pitch malrotation is substituted for
terms like steep occlusal plane, at occlusal
plane, and steep mandible. Roll and yaw malrotations can be right or left. In roll, right or left tells
us the side where teeth are lower, like an airplane
that is rolling to the right will have its right wing
down. For yaw, right or left species where maxilla is pointing—when the pointer of its anteroposterior axis is towards the incisors. Pitch
malrotation can be excessive or insufcient. In
excessive pitch malrotation, the inclination of the
jaws is steep. In insufcient pitch malrotation,
the inclination is shallow, at, or reversed. Their
nal alteration of the current terminology is to
use distinctive terms to distinguish between the
two different types of asymmetries: plain asymmetry which refers to object (intrinsic) asymmetry and the qualied term asymmetric alignment,
which refers to jaw misalignment in relation to
the sagittal plane of the face (Fig.11.2).
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