The jaw bone
The jaw bone is the largest equine face, comprises two
mandibles that fuse at the symphysis at 2-3 months of age. The mandible
articulates with the temporal bone in Temporomandibular Joint and contains the
alveoli of the mandibular incisors, canines, and wolf teeth (if present)
The ventral edge of the horizontal branch of the jaw
is broad and rounded at the young horse, because it contains the reserve crowns
of the teeth of the mandible and, conversely, becomes thinner and sharper in
older horses submit molars erupt. Some breeds, especially the descendants of
the Arabian horse (which in turn are descended from Equus Cracoviensis) have
mandibles and jaws and proportionally shallow crowns short book, while most
other breeds, eg derived from E. muniensis (Pony mountain) or E. mosbachensis
and types of English pony race (as Exmoor ponies) have alveoli booking for deep
and long crowns. It has been proposed that the junctions between these two
types of horses can develop pronounced swelling ventral developing below the
apices of the teeth of the second and third jaw due to an imbalance between the
depth and length of the mandibular tooth. These erupting
mandibular cysts ('bony tubercles')
(JAW WITH TEETH)
Incisors
The horses have incisors, canines and molars. Horses
are DIFIODONTOS; ie have two types of dentures, are other words that there are
teeth (deciduous) and permanent teeth (perennial). This means that when they are
foals teeth are smaller according to their maxilla or mandible. When baby teeth
fall out are replaced by larger parts provided to the growth of the mandible
and maxilla.
The horses have 6 incisors, 2 canines and 6 molars in
each jaw for a total of 40-42 teeth in males and 36-38 parts mares, some
exceptions where some mares have canines or fangs.
Equine dental formula:
Decidua: 2 (DI 3/3, 0/0 DC, DPM 3/3) = 24 teeth
Horses: 2 (I 3/3 - 1/1 C - P 3-4 / 3 - M 3/3) = 40-42 teeth
Mares: 2 (I 3/3 - 0/0 C - P 3-4 / 3 - M 3/3) = 36-38 teeth
The incisors have a particularity and is a depression
on your table or face chewing tapered and is called external tooth turbinate,
plus its roots are shallow and have no internal depression called turbinate
tooth.
The incisors are long and narrow. Neck poorly marked.
The occlusal surface enamel presents an invagination to form the infundibulum,
it lasts up to ten years. Permanent incisors are flattened back and forth in
its upper half, its lower half side in the intermediate portion and has a
transition between the two flattened. This arrangement will give us cross
sections whose anger surface from the elliptical to biangular, passing
successively through the oval, round and triangular. When wear reaches the pulp
cavity, a new layer of dentin appears dental forming star or star Girard.
Rash Of Deciduous incisors
The central incisors erupt or tweezers during the
first week of life, average between 4 and 6 weeks of age and extreme body 6 and
9 months old. This also varies between the different races.
Eruption Of Permanent
Incisors
The change of the incisors can begin in the mandibular
incisors (mandibular refers) or maxillary (refers to maxilla) interchangeably,
but always by central incisors or tweezers happens at 2 years and a half, the
incisors media and 3½ years and ends at 4 and a half years.The canine teeth
erupt at 4 and a half to 5 years in males, in females are absent or
rudimentary. Changes in the occlusal surface
Emergence of Dental Star
Star tooth structure is a yellow brown displayed on
the occlusal surface through wear, which is linearly and then finally becomes
rounded oval, is located facially (Lip) to the dental crown and then moves to
the center. This structure appears sequentially in the central incisors to five
years, in the media at age 6 yen ends to 7-8 years.
The characteristic blot dental star appears in the
central incisors 7-8 years and in the media 9 to 11 years. At the ends is
highly variable and it does between 9 and 15 years.
Brands
The brands relate to shape the contours of the chewing
surface of the tooth. They are becoming smaller and are moved and rounded
tongue. As the remaining cement wears the mark disappears from the occlusal
surface. Trademarks are oval and large in the central incisors up to 6-7 years
between 7 and 8 years become triangular. Anyway there are many racial
differences and is one of the most variable characteristics, so it is not taken
into account for determining age. This assessment also accounts for the disappearance
of these brands, ranging between 12-20 years at the central incisors depending
on the breed.
Changes In The Shape
Occlusal Surfaces
They are very inaccurate indicators of age in addition
to the various successive forms merge together. The forms are observed
sequentially in central and middle incisors are oval, trapezoidal, triangular
with sharp apex toward the lingual side and biangular respectively. The shape
of the ends does not fit incisors sequential changes of the other incisors.
Brands have disappeared from all the lower incisors. The
occlusal surfaces are triangular with apex at the central lingual and labial
means and the ends.
The arch formed by the incisors of opposing jaws
profile observed varies with age in young are positioned almost straight (180
°) from the 10 years the angle between them becomes more acute.
The upper and lower incisors are located almost
straight with each other. Forming a hook (dovetail) on the incisal end observed
The angle between the lower incisors is sharper than
in the previous figure. You can see in the upper end incisive Groove Galvayne
over the full length of his labial surface.
About Incisive Superior
Extreme Hook Or Swallow Tail
The dovetail is a hook formed on the upper incisor
caudal end by the slower wear of the tooth. When the upper teeth acquire the
inclined position with the bottom, the end in which the hook is formed again
with the opposite contact and the hook tooth disappears.
It has always been considered as a typical
characteristic of the horses of 7 or 14 years, however, only a very small
percentage of horses 7 years and Horses 14 have the hook on the upper ends
incisors ( 13% and 8% respectively). On the other hand a varied horses 5 and 6
percentage, between 8 and 12 years, and horses over 13 years also showed these
characteristics (14%, 22% and 13% respectively). Therefore it is not related to
any specific age and would be irrelevant to the estimated age.
Groove De Galvayne
It is a characteristic groove ends horse incisors over
11 years. However their presence, length and bilateral symmetry is variable and
inconsistent so it has little use in determining equine age.
In conclusion The dental age estimation can be
performed fairly accurately until 7 or 8 years old, based almost exclusively on
the eruption of permanent incisors and canines, and the occurrence of dental
and dental evenness star (disappearance of dental) crown. The other features
are very specific to each individual and would be very risky consideration
regardless of the above factors (anamnestic data, race, sex, age, food,
containment system, dental conformation, approximate age, etc.)
Masticatory movement as equines is rotating and this
produces a molar wear in certain areas while the opposite side that suffers a
friction increases and form points or edges. These edges in the upper molars
grow on the outside ie towards the cheeks while the lower molars grow inwards
ie towards the language
(Skull Side View)
Mandibular fractures are the most frequent facial
trauma after nasal fractures , be of veterinary medical consultations . Its
etiology is determined by impacts in the lower third of the face being the most
frequent accidents trauma, although the attacks , practice extreme sports like
bull tailing , are other causes of lower frequency.
The agent may cause direct mechanism fracture
(fracture occurring at the site of injury) or indirect (very common in severe
condylar fractures sinfisarios trauma).
Fracture line which follows a path anterioinferior, ie
downwards and forwards horizontal fractures are considered favorable because it
tends to fracture
stability by action of the anterior and posterior
muscles (masseter and medial pterygoid)
(FRONT FRACTURES)
Unfavorable vertical fractures in line passes from
back to front and inward. The jaw bone is a U-shaped conditioning function.
This is an exposed, strong, mobile and involved in speech and feeding bone. It
is rather muscular and ligamentous insertion teeth being responsible for the
articulation with the maxilla. We can distinguish two main divisions: horizontal
(above) that supports the teeth and vertical (posterior) where the muscles of
mastication are inserted and how the temporomandibular joint (TMJ). The
mandibular anatomical regions are: a cellular and other symphyseal; the body,
the angle and ramus and the coronoid and condylar process.
(SPLIT SIDE LEFT)
Mandibular fractures are usually located in regions
with a weakness and bone structure which has a lower resistance (eg the
mandibular condyle) or there is an edentulous or presence of impacted teeth,
cysts or long tooth roots. The row of teeth of the jaw are arranged such that
the front teeth are closer to the vestibular side, while molars are located
toward the lingual side of the jaw. The mandibular dental arch resembles a
parable in which occlusive surfaces of the molars tend to be rectangular
(uppers are more diamond). The cusps are buccal and lingual provision. The
lower molars have two roots, one medial and one distal. Finally, the blood
supply is provided mainly from the inferior alveolar artery (branch of the
maxillary artery), speaking also the facial artery and irrigation through the
insertions of the regional muscles.
(RIGHT SIDE SPLIT)
There are two nerves that may be involved in this
disorder: the marginal branch of the facial nerve and the mandibular division
of the trigeminal nerve. The inferior alveolar nerve enters the medial aspect
of the bone through the mandibular foramen and through the angle and into the
body of the mandibular canal. The facial nerve divides at the level of the
parotid gland in cervicofacial branches temporofacial and then giving the
temporal, zygomatic, buccal, marginal, cervical branches. The latter moves
towards the symphyseal region under the plane of the platysma muscle.
CLASSIFICATION
Fractures in the dental arch
Sinfisarias fractures and
parasymphyseal: Isolated
fractures of the mandibular symphysis are rare because when present are often
accompanied condyle fractures. Represent a low displacement and when they are
multiple staggering can be observed. The fracture is usually oblique or
horizontal. The parasymphyseal are more frequent and, as sinfisarias, often
accompanied by articular condyle fractures or angle of the jaw. Be careful when
handling avoiding damage
the mental nerve.
Fractures of the region of
canines: This is the
place where most often settle fractures inside the dental arch. These are
fractures that can pass through the mandibular body producing displacements due
to the force exerted by the muscles responsible for chewing.
Fractures of the body of the
mandible: are fractures
of the posterior teeth ranging from canines to the mandibular angle. In such
displacements and graduation are frequent.
Fractures outside the dental
arch
Fractures of the mandibular
angle: angle
fractures are common and are associated on many occasions contralateral condyle
fractures or other level. Are often underlying injuries that favor the
existence of third molars or follicular cysts that weaken the bone and make
more inclined mandibular angle fracture side impact (it is in these cases of
open fractures to break the stroke in the molar or cystic region). They are
fractures that can present problems of ossification.
Fractures of the mandibular
branch: fractures are
rare in the absence of displacement is most commonly found. The production
mechanism is usually by direct impact.
Longitudinal fracture: No displaced.
Transverse fracture: You Displaced per share of the
temporalis muscle.
Fractures of the mandibular
condyle: The condyle is
a place where often settle mandibular fractures due to their relative
structural weakness, despite being protected within the glenoid fossa. Most
fractures sometimes indirect or shearing and bending is not altering the current
occlusion than the existence of a previous bite. Can I be unilateral or
bilateral and classified according to the displacement and overlapping
fragments. It is considered that serious deviation exceeding 30 ° to the distal
fragment and major shift to one in which the overlap of the fragments is
greater than 5mm. The commitment of the vascularity of the proximal fragment
often results in avascular necrosis. Other common complications are
osteoarthritis, temporomandibular joint pain, disc avulsions, hemarthrosis /
hematoma which can result in ankylosis.
(Exposition of the incisors)
Classification of orthopedic
surgery:
Reconstruction: when it comes to soft tissue, capsules, ligaments,
tendons, bone cartilage. Here the internal fixation of fragments included
through fragmentary Inter compression, through screws, plates and external
coaptation or through external fixation plaster splint. There are also surgical
removal, you must remove fragments, if for example, some broken jaw, what is
done is to remove the segments that may be driving the emergence of
osteomyelitis, removing small fragments of bone or cartilage in case joints and
also eliminate degenerated cartilage, osteophytes or hypertrophic synovial
membranes, that includes the orthopedic surgical removal.
To treat only those not displaced, stable (favorable)
or incomplete fractures in which no changes are objectified in the occlusion,
subsidiaries will be treated only with a soft diet, rest all articulate and
expectant attitude. Usually conservative and functional treatments are
preferred. The goal of conservative treatment is to allow a good function
without complete anatomic reduction due to early mobilization. Surgical
treatment also seeks to restore most perfectly anatomical position.
Conservative Treatments
Cerclages: Cerclages are a good treatment for mandibular
fractures as well as appropriate adjuvant option to other techniques
(Grafica cerclage)
This case is presented in Guayabo del Zulia state, an
equine coleus called the congo, who suffered a product of a foot injury causing
him other equine tip the injury.
I reach the
Lapita to the farm where is the horse with Dr. Manuel Velasco, veterinarian in
the area with many years of experience and seeing astonishment us because we do
not expect the magnitude of the injury, based on basic knowledge of anatomy, in
the available resources had on hand and the help of God proceeded to demolish
the horse under general anesthesia and I find what I can see in this video.
https://youtu.be/zWNII9F2Qm8
(Video 1 compound fracture of mandible incisors
exposure)
Only had on hand some medicines, antiseptics, gauze,
surgical equipment and willingness to help this issue. I asked the owner sweet
wire, drill and thin wicks and complements the team podiatry.
After fully anesthetized horse perform curettage
eliminating all pollutants and the necrotic tissue, with drill trace lines in
canines and incisors ends in order that the wire does not run so you can make
the relevant cerclage for this case.
(Doctor Manuel Velazco helping with the procedure)
These were the
results shown on the same day we attended the horse
(Left side view
cerclage)
(Vista lateral Izquierda del cerclaje)
After being
subjected to soft diets early days and helped with fluid, antibiotics and
anti-inflammatory drugs the horse was released to pasture where he continued
his normal life. Passing 8 weeks back and I get this:
Cerclage horse
with multiple broken jaw:
All work
was successful dental pieces were in place, jaw had successfully soldier, so I
proceeded to remove the cerclage
(Removing
the cerclage)
After
removing the horse cerclage was observed as follows:
(Front
View)
(Right Side
View)
(Front
View)
@CABALLOSALUDMÉRIDA
M.V. Hugo Antonio
Useche Romero
Médico Veterinario
Practicante en Equinos
Especialista en
Reproducción y Podología Equina
Instagram: @caballosaludmerida
Mail: hugoantoniouseche@hotmail.com
Facebook: Hugo Antonio Useche Romero
Twitter: @mvhugouseche
Teléfono: 04149779165/ 0416 6760255
Pin: 7F521CE5
Dr.Carlos Federico Rodriguez Garantón. GRADUADO EN LA UCV-FCV 1987 MI VIDA DEDICADA A LOS CABALLOS CRIADO EN EL CAFETAL CCS VENEZUELA. HE TRABAJADO CON CABALLOS DE PASO FINO EN TODOS LOS PAÍSES DONDE EXISTEN Y HE JUZGADO, MONTADO, HERRADO, CURADO CABALLOS TODA MI VIDA. PADRE DE CARLA GABRIELA Y ALEXANDRA RODRIGUEZ. HIJO DE ALÍ RODRÍGUEZ Y ELSA GARANTÓN NICOLAI. COLIE DESDE LOS 12 AÑOS HASTA LOS 25 Y CLASIFIQUE A 6 CAMPEONATOS NACIONALES POR EL ESTADO MIRANDA. TRABAJE 13 AÑOS COMO DIRECTOR DE LOS SERVICIOS VETERINARIOS DE LOS HIPÓDROMOS DE VENEZUELA. AHORA DEDICADO A ENSEÑAR TODO LO QUE SE A TODO EL QUE QUIERA APRENDER DE MI. DIOS ES MI GUÍA!. AMEN!
