THE JAWS, INCLUDING THE TEETH AND GUMS
TEETH: Dental caries--Impacted wisdom tooth. GUMS: Gingivitis;
Pyorrhoea alveolaris; Hypertrophy; Epithelioma. JAWS: Pyogenic
affections: _Periostitis_; _Osteomyelitis_; Tuberculosis;
Syphilis; Actinomycosis--Tumours: _Of alveolar process_; _Of
maxilla_; _Of mandible_--Fracture of maxilla--Fracture of
mandible--Affections of the temporo-mandibular articulation:
_Dislocation of the mandible_; _Acute arthritis_; _Tuberculous
arthritis_; _Arthritis deformans_; _Closure of the jaws_.
#Dental caries# is a process of disintegration which begins in the
enamel of a tooth--usually in the region of its neck--and gradually
extends through the dentine till the pulp cavity is reached.
Infection of the exposed pulp cavity may set up an acute purulent
_pulpitis_. This is associated with severe pain, which is not confined
to the diseased tooth, but may spread to adjacent teeth, and sometimes
to all the branches of the trigeminal nerve on the same side of the
face.
The infection may spread from the tooth to the alveolo-dental
periosteum, and set up a _periodontitis_. In the affected tooth there
is at first a feeling of uneasiness, which is relieved by the patient
biting against it. Later there is severe lancinating or throbbing
pain. The affected tooth usually projects beyond its neighbours, and
is excessively tender when the opposing tooth comes in contact with it
in mastication. The gum becomes red and swollen, and the cheek is
oedematous.
Periodontitis is usually followed by the formation of an _alveolar
abscess_. The pus, which forms at the root of the tooth, in most cases
works its way through the bone and into the gum, constituting a
"gum-boil." The pus may then burst through the gum, or may spread
underneath the external periosteum of the jaw and lead to necrosis.
In some cases the cheek becomes adherent to the gum and to the jaw
before the abscess bursts, and the pus escapes through the skin,
leaving a sinus which leads down to the defaulting tooth, and which is
slow to heal, usually because there is a small sequestrum at the
bottom of it. The opening of the sinus is most commonly situated at
the under margin of the mandible a little in front of the masseter
muscle. An alveolar abscess deeply seated in the maxilla may open into
the maxillary antrum and set up suppuration in that cavity. To avoid a
scar on the face, the abscess should be opened from the mouth. A
periodontal abscess of one of the upper central incisors spreads
backwards between the muco-periosteum and the bony palate, causing an
elongated swelling in the roof of the mouth.
In all cases the extraction of the carious tooth is necessary before
the abscess will cease discharging and the sinus heal. If a sequestrum
is present it must be removed, and the bone scraped with a sharp
spoon. Among the other effects of dental caries may be mentioned
localised necrosis of the alveolar margin, cellulitis of the neck, and
enlargement of the cervical lymph glands.
A _cyst_ is frequently found attached to the root of a decayed tooth.
It is lined with epithelium, and is probably derived from a belated
portion of the enamel organ which has been stimulated to active growth
by infective processes in the pulp cavity. It is seldom larger than a
pea, and contains a pultaceous mass like inspissated pus. It gives
rise to no symptoms, and is only recognised after extraction of the
root.
_Odontomas_ have already been described (Volume I., p. 192).
A localised swelling of the mandible, associated with pain referred to
the ear and neck, and in some cases with spasmodic contraction of the
muscles of mastication, may be due to _impaction of the wisdom tooth_
(lower third molar). If the tooth is merely embedded in the gum,
incision may allow of its eruption; if the X-rays show that it is
wedged under the second molar it must be extracted, and this may prove
a difficult dental operation.
#Affections of the Gums.#--Inflammation of the
gums--_gingivitis_--usually occurs in association with a general
stomatitis. The gums are swollen and spongy, and may show superficial
ulceration, associated with bleeding and extreme foetor of the breath.
The teeth become loose, project from the alveoli, and sometimes fall
out. These symptoms are prominent in cases of scurvy, and of chronic
mercurial poisoning. In chronic lead-poisoning a characteristic blue
line is seen on the gums near the dental margin. The _treatment_
consists in removing the cause, improving the hygienic and dietetic
conditions of the patient, and administering lime-juice, iodide of
potash, quinine, or cod-liver oil, according to the cause. Antiseptic
mouth-washes and dentifrices are also indicated. Chlorate of potash,
being excreted in the saliva, is particularly useful.
_Pyorrhoea alveolaris_ is a chronic form of gingivitis, met with after
middle life, which begins in relation to the necks of the teeth and
the alveolo-dental periosteum. It is due to bacterial infection, and
is associated with an accumulation of tartar between the gums and the
teeth. A muco-purulent discharge escapes from within the free edge of
the gum and alveolus. The alveolar borders and the gum subsequently
undergo atrophy, so that the roots are exposed, and the teeth are
liable to become loose and eventually to fall out. The condition may
only affect a few teeth, or it may spread to them all, in which case
the patient may in the course of some years become edentulous.
Gastro-intestinal disturbances, chronic joint affections of the nature
of arthritis deformans, a form of pernicious anaemia, and other general
conditions have been attributed to the absorption of toxic products.
The _treatment_ consists in removing the tartar from the teeth,
applying strong antiseptics to the groove between the teeth and the
gums, and employing mouth-washes and dentifrices. Massage of the gums
night and morning, and rubbing in a paste of chlorate of potash and
menthol, is often of great value. Good results have followed the use
of vaccines and improvement of the general health.
_Hypertrophy of the gums_ is occasionally met with in children and
young adults who are mentally defective, and the teeth appear early
and are abnormally large. The gum almost buries the teeth, and large
polypoid masses form which tend to fungate. The treatment consists in
removing not only the hypertrophied gums, but also the affected
alveolus (Heath).
A localised hypertrophy--_polypus of the gum_--sometimes results from
the irritation of a carious tooth, or from the pressure of an
artificial denture, and may simulate an epulis (p. 513). The swelling
is usually pedunculated, and if cut away close to the alveolar margin
does not tend to recur.
_Epithelioma_ sometimes originates in the gum in relation to a carious
tooth or to an artificial tooth-plate. The growth tends to invade the
bone and to spread to the cheek or buccal mucous membrane, or to the
maxillary antrum, and its malignant nature is suggested by its
persisting after the removal of the irritation. The only treatment is
early and complete removal of the growth and the adjacent segment of
bone.
Other tumours of the gums, such as angioma and papilloma, are rare.
THE JAWS
#Pyogenic Infections.#--The jaws may be infected in fractures
communicating with the mouth or as a result of the unskilful
extraction of teeth, but the majority of pyogenic infections originate
in relation to carious teeth, beginning as a periodontitis which is
followed by diffuse periostitis that may lead to necrosis of
considerable portions of bone. In workers exposed to the fumes of
yellow phosphorus, the bone may be so devitalised that it readily
becomes infected with pyogenic organisms and undergoes a process of
cario-necrosis--the _phosphorus necrosis_ of the older writers.
[Illustration: FIG. 247.--Cario-necrosis of Mandible.]
_Acute osteomyelitis_ occasionally attacks the mandible, less
frequently the maxilla. Pus rapidly forms under the periosteum, and a
considerable area of bone may undergo necrosis.
In _cancrum oris_, also, the bones are frequently attacked and may
undergo necrosis.
The _treatment_ is to let out the pus, and, whenever possible, this
should be done from the mouth to avoid a cicatrix on the face. When
the angle or the ascending ramus of the mandible or the facial portion
of the maxilla is involved, it is not possible to avoid making an
external opening. Drainage is secured, and the mouth kept sweet by the
frequent use of antiseptic washes. When the condition is due to a
carious stump or to an unerupted tooth, this should be extracted at
the same time as the abscess is opened.
The separation of a sequestrum is usually slow, taking from two to
four months according to the acuteness of the infection and the extent
of the necrosis. In the mandible the sequestrum becomes surrounded by
a sheath of new periosteal bone, so that, even if the greater part of
the jaw undergoes necrosis, the arch is reproduced, and after removal
of the sequestrum little or no deformity results. The sequestrum can
usually be removed after dividing the mucous membrane and gouging away
a portion of the outer aspect of the new sheath. The cavity is packed
with iodoform or bismuth gauze. When the ascending ramus is involved,
precautions must be taken to prevent fixation of the jaw taking place
during the healing process. In the maxilla no new case is formed, and
deformity results from sinking in of the cheek, unless this is
prevented by wearing a plate made by the dentist.
#Tuberculous disease# is comparatively rare. It is occasionally met
with on the orbital margin of the maxilla and in the region of the
zygomatic (malar) bone. In the mandible it usually occurs near the
angle. Stockman isolated the tubercle bacillus from a series of cases
of "phosphorus necrosis" investigated by him. The sinuses that form
when a cold abscess bursts on the surface are peculiarly intractable
and only heal after the diseased bone has been removed, leaving a
characteristically depressed scar, which is adherent to the bone.
#Syphilitic# affections are also rare. A localised gumma may develop
in the neighbourhood of the angle of the mandible, or the whole of the
body of that bone may be the seat of a diffuse gummatous infiltration
(Fig. 248). In either case the clinical importance of the condition
lies in the fact that it is liable to be mistaken for a new growth,
such as an osteo-sarcoma, or for actinomycosis.
[Illustration: FIG. 248.--Diffuse Syphilitic Disease of Mandible.]
#Actinomycosis.#--This condition is met with in the jaws more
frequently than in any other part, and the mandible is attacked
oftener than the maxilla. The actinomyces gain access to the bone
through a carious tooth or through the gum.
At the outset the patient complains of pain and tenderness referred to
one or more carious teeth. Within a few weeks a swelling forms--in the
mandible near the angle as a rule, and in the maxilla in some part of
the cheek. The swelling, which varies in consistence, implicates the
bone and cannot be moved apart from it. The skin over it becomes red,
suppuration occurs, and sinuses form and give exit to a sero-purulent
fluid in which the characteristic yellow "sulphur grains" may be
detected. The surrounding soft tissues are infiltrated, and the part
becomes riddled with sinuses, which lead down to bare bone. The
disease usually runs a chronic course, lasting for one or two years,
and, unless pyogenic infection is superadded, is not attended with
fever.
In the absence of the characteristic yellow granules, actinomycosis
may readily be mistaken for tuberculous or syphilitic disease, or for
sarcoma.
The _treatment_ consists in removing the diseased tissue with the
knife or sharp spoon, and in the administration of large doses of
potassium iodide. The insertion of tubes of radium has a beneficial
effect.
#Tumours of the Alveolar Process.--Epulis.#--The tumours that grow
from the alveolar processes of the jaws appear at first sight to
spring from the gums, hence the term _epulis_, generally applied to
them. They really originate in the periosteum of the alveolus or in
the periodontal membrane, and are essentially of the nature of
fibro-sarcoma. In some, the fibrous element predominates, but the
frequency with which they recur after removal, unless the segment of
bone from which they spring is also excised, indicates their malignant
tendency. In most cases the tumour is of the myeloid type--myeloma; in
others new bone is formed in its substance--osteo-sarcoma.
An epulis usually begins in the gap between two teeth, and grows
slowly, either towards the cavity of the mouth, or more frequently
towards the lip or cheek, where it appears as a bright red, smooth,
firm, rounded swelling, which is adherent to the jaw, and may be
sessile or pedunculated (Fig. 249). It causes little pain, but is
liable to interfere with mastication. As it increases in size it
spreads over the alveoli of several teeth, becomes softer, and assumes
a dark violet colour, and if subjected to pressure or irritation may
ulcerate and bleed.
[Illustration: FIG. 249.--Epulis of Mandible.
(Anatomical Museum, University of Edinburgh.)]
The true alveolar tumour is to be diagnosed from a mass of redundant
granulations such as may form in relation to a carious tooth, from a
polypus or an epithelioma of the gum, a tumour of the body of the jaw,
or an angioma.
The _treatment_ consists in removing the tumour together with a
wedge-shaped or quadrilateral portion of the alveolar process from
which it grows. A dental plate should be fitted to fill up the gap in
the alveolus. After such free removal these tumours show little
tendency to recur and metastases are rare.
#Malignant Tumours of the Maxilla.#--All varieties of _sarcoma_ and
_carcinoma_ are met with; of the former, the round and spindle-celled
are the most common. Carcinoma occurs chiefly in two forms, less
commonly a columnar epithelioma arising from glandular epithelium,
much more commonly a squamous epithelioma either originating within
the antrum and causing its expansion, or spreading to the maxilla from
the mucous membrane of the nose or mouth. Clinically it is practically
impossible to differentiate sarcoma from carcinoma; in the later
stages the infection of the glands below the mandible is more marked
in carcinoma. An important point to determine is whether the growth
arises within the maxilla or has spread to it from adjacent parts,
such as the base of the skull, the nose, or the palate. In this the
X-rays are helpful. Their malignancy is evidenced by the rapidity of
their growth, the manner in which they infiltrate adjacent parts, and
the frequency with which they recur after removal. They occur at all
ages, and have been met with even in children.
The _clinical features_ vary according to whether the tumour
originates on the anterior aspect of the bone, in the maxillary
antrum, or on the posterior aspect.
When the tumour originates in the periosteum covering the front of the
bone, it forms a swelling under the cheek, usually in the vicinity of
the zygomatic (malar) bone, and grows towards the mouth as well as
towards the surface. The cheek is gradually invaded, and in some cases
the growth extends into the maxillary sinus.
The typical malignant tumour of the upper jaw originates in the lining
membrane of the antrum; it first fills the cavity and then bulges its
walls in every direction, so that, on pressure being made over the
swelling, the osseous shell of the sinus dimples and crackles under
the finger. The sinus is dark on trans-illumination. The tumour may
obstruct the nostril on the same side, and, by pressing on the tear
duct, may cause the tears to flow over the cheek. It may be seen
through the anterior nares, and may be attended with a sanious
discharge from the nose. The eyeball is liable to be displaced
upward, and if the ethmoid cells are invaded, it is also pushed
outward; the palate may be depressed and the cheek projected (Figs.
250, 251).
[Illustration: FIG. 250.--Sarcoma of the Maxilla.]
[Illustration: FIG. 251.--Malignant Disease of Left Maxilla, which
displaced the eyeball and caused double vision.]
When the tumour grows from the periosteum of the posterior aspect of
the bone, and extends into the spheno-maxillary or pterygo-maxillary
fossa, the eyeball is usually protruded by the invasion of the orbit
from behind, and a swelling appears in the temporal region. If the
sinus is invaded, the tumour spreads in the various directions already
indicated. Not infrequently a tumour, which appears to have its seat
in the maxilla, is really a downward prolongation of a growth
originating in the base of the skull, a point on which the X-rays may
yield valuable information.
In all cases the tumour tends to infiltrate the surrounding tissues
indiscriminately. There is severe pain referred to the distribution
of the maxillary division of the trigeminal nerve. Haemorrhage is
liable to occur when exposed portions of the tumour ulcerate--for
example in the nasal fossae. Sarcoma is to be distinguished from the
solid and cystic forms of odontoma, which also may distend the bone,
bulging the hard palate and projecting on the face.
_Treatment of Malignant Disease._--Without the help of radiation the
results of operative treatment of malignant disease of the maxilla are
far from encouraging. Probably the best line to follow is to embed
several tubes of radium in different parts of the tumour for several
days, and when the resulting shrinkage of the growth appears to have
attained its limits, the maxilla should be excised. If on microscopic
examination it is found to be a carcinoma, the glands on the same side
of the neck should be removed at a second operation on lines similar
to those in Butlin's operation in cancer of the tongue. The aid of the
dentist is required to fit a denture which will at least restore the
hard palate and alveolar margin. The operation of excising the
upper jaw is not a dangerous one, especially if the risk of
broncho-pneumonia is minimised by the intra-tracheal administration of
ether. The final illness in cases of malignant disease of the upper
jaw left to nature, or when it has recurred after operation, is a
terrible one; the growth displaces and destroys the globe, blocks the
nose and fungating on the face, causes hideous disfigurement.
#Simple tumours# are rare. _Fibroma_ may originate in the periosteum
or in the lining membrane of the maxillary sinus. It usually tends to
assume the characters of sarcoma. _Chondroma_ usually begins either on
the nasal surface of the bone or in the maxillary sinus. _Osteoma_
occurs in two forms: the exostosis, which may be composed of
cancellated or of compact tissue, and the diffuse osteoma or
leontiasis ossea (Volume I., p. 485). All intermediate forms are met
with, and when confined to the maxilla, the resulting disfigurement
may be improved or remedied by operation; the cheek is raised or
reflected and the bone shaved away with a strong knife or osteotome.
#Tumours of the Mandible.#--The same varieties are met with as in the
maxilla. The non-malignant forms--osteoma, chondroma, and fibroma--are
rare.
A _dentigerous cyst_ appears as a smooth, rounded, and painless
swelling, usually in the region of the molar teeth. The bone gradually
becomes expanded and crackles on pressure. The cyst is filled with a
glairy mucoid fluid, and may contain one or more unerupted teeth (Fig.
252). The X-ray appearances are characteristic. The treatment consists
in removing the anterior wall of the cyst, scraping the interior, and
packing the cavity with iodoform or bismuth gauze.
[Illustration: FIG. 252.--Dentigerous Cyst of Mandible containing
rudimentary tooth.
(From Sir Patrick Heron Watson's collection.)]
The myeloid tumour or _myeloma_ is comparatively common. It develops
in the interior of the bone and expands the affected segment (Fig.
253). It grows slowly, is more or less encapsulated, and therefore
does not infiltrate the surrounding tissues. Sometimes it so weakens
the bone that pathological fracture occurs. There is no glandular
involvement, and the tumour shows little evidence of malignancy.
[Illustration: FIG. 253.--Osseous Shell of Myeloma of Mandible.
(From Professor Annandale's collection.)]
The _periosteal sarcoma_ is the most malignant form. It grows rapidly,
and infiltrates the surrounding tissues. The submaxillary salivary
glands and the cervical lymph glands are usually implicated, and the
disease tends to spread by metastasis to distant parts.
_Epithelioma_ is the commonest new growth affecting the mandible; it
usually involves the central portion of the bone, being a direct
spread from the lower lip, tongue, or floor of the mouth. When it
originates in the pillars of the fauces it implicates the ascending
ramus. In all cases the infection of the cervical lymph glands is a
serious factor both in prognosis and treatment.
_Treatment._--_Partial removal_ of the mandible may be undertaken for
myeloma, and in cases of sarcoma and epithelioma in which the tumour
is limited to a small area of the bone--for example, to the alveolar
process, the angle, the horizontal ramus, or the symphysis; in other
cases, the whole bone must be removed.
INJURIES OF THE JAWS
#Fracture of the Maxilla.#--Fractures of the maxilla are nearly always
due to direct violence, such as a blow on the face, a stab, or a
gun-shot wound. They are often rendered compound by opening into the
mouth, into the maxillary sinus, or on to the skin of the cheek. The
alveolar process, in whole or in part, may be separated from the body
of the bone by a severe blow, such as the kick of a horse, and when
the whole alveolus is detached, it may carry with it the hard palate.
Limited portions of the alveolus are frequently broken in the
extraction of teeth. The main trouble after severe alveolar fractures
is that the upper teeth do not accurately oppose the lower ones, and
mastication is thereby interfered with.
When the frontal (nasal) portion of the maxilla is broken, the
lachrymal sac and nasal duct may be damaged and the flow of the tears
obstructed. In such cases emphysema is also liable to develop.
Fractures of the facial portion are frequently complicated by
haemorrhage from the infra-orbital vessels, and anaesthesia of the area
supplied by the infra-orbital nerve. Suppuration may occur in the
maxillary sinus. In some cases the maxilla is driven in as a whole,
and in others the fracture radiates to the base of the skull and
cerebral symptoms develop.
The _treatment_ consists in reducing any deformity that may be
present, ensuring efficient drainage, and keeping the mouth as aseptic
as possible. Union takes place rapidly, and owing to the vascularity
of the parts necrosis is rare, even when suppuration ensues. When the
alveolar portion is comminuted, the fragments may be kept in position
by fixing the mandible against the maxilla by means of a four-tailed
bandage (Fig. 255), or by adjusting a moulded lead or gutta-percha
splint to the alveolus and palate.
The _zygomatic (malar) bone_ is sometimes fractured by direct
violence, along with the adjacent portion of the maxilla. It may be
possible to manipulate the displaced fragments into position with the
fingers introduced between the cheek and the gum; if this fails, a
small incision should be made in the mucous membrane anterior to the
masseter, and the bone levered into position with an elevator.
The _zygomatic arch_ is occasionally fractured by a direct blow. As
the depressed fragments are liable to interfere with the movement of
the mandible, they should be elevated either by manipulation or
through an incision.
#Fractures of the Mandible.#--The most common situation for fracture
of the mandible is through the _body_ of the bone in the vicinity of
the canine tooth (Fig. 254). The depth of the socket of this tooth,
and the comparative narrowness of the jaw at this level, render it the
weakest part of the arch. The fracture is usually due to direct
violence, such as a blow with the fist, the kick of a horse, or a fall
from a height. It is sometimes bilateral, the bone giving way at the
canine fossa on one side and just in front of the masseter on the
other; or both fractures may be at the canine fossae. The fracture is
usually oblique from above downwards and outwards, and is nearly
always rendered compound by tearing of the mucous membrane of the
mouth.
[Illustration: FIG. 254.--Multiple Fracture of Mandible.
(From Sir Patrick Heron Watson's collection.)]
When only one side is broken, the smaller fragment is usually
displaced outwards and forwards by the masseter and temporal muscles,
so that it overlaps the larger fragment. In bilateral fractures the
central loose segment is driven downwards and backwards towards the
hyoid bone by the force causing the fracture, and is held in this
position by the muscles attached to the chin, while both lateral
fragments are tilted outwards and forwards by the masseters and
temporals. The amount of displacement is best recognised by observing
the degree of irregularity in the line of the teeth. Abnormal mobility
and crepitus are readily elicited, and there is severe pain,
particularly if the inferior dental nerve is stretched or crushed. The
patient's attitude is characteristic; he supports the broken jaw with
his hands, and keeps it as steady as possible when he attempts to
speak or swallow. Saliva dribbles from the open mouth, and the speech
is indistinct.
In adults, the bone may be broken at the _symphysis_ as a result of
lateral compression of the jaw--for example, pressing together of the
angles. The general characters of the fracture are the same as those
of fracture of the body, but the displacement is inconsiderable.
Fractures of the _angle_ and through the _ramus_ are less common, and
are not attended with deformity, as the fragments are retained in
position by the masseter and internal pterygoid muscles. Fracture of
the _coronoid process_ is rare.
The _condyle_ is usually fractured just below the insertion of the
external pterygoid muscle (Fig. 254) by a fall on the chin or by a
severe blow on the side of the face. When the fracture is unilateral,
the broken condyle is tilted inwards and forwards by the external
pterygoid, and can be palpated from the mouth, while the rest of the
jaw is displaced _towards_ the affected side, and not away from it, as
happens in unilateral dislocation. When the fracture is bilateral, the
mandible falls backwards, so that the lower teeth lie behind those of
the maxilla.
In a few cases the condyle has been driven through the floor of the
glenoid cavity, causing fracture of the base of the skull. The
diagnosis may be established by means of the X-rays.
_Complications._--As the majority of these fractures are compound,
suppuration is comparatively common during the process of repair, but
if means are taken to keep the mouth clean it can usually be kept in
check, and seldom leads to necrosis. The teeth adjacent to the
fracture are liable to be loosened or displaced. If merely loosened
they should be left in place, as they usually become firmly fixed in
the course of a few days. Care must be taken that a displaced tooth
does not pass between the fragments, as this has been the cause of
difficulty in reducing a fracture and of its failure to unite.
Irregular union, by destroying the alignment of the teeth, leads to
interference with mastication. The bone usually unites in from four to
six weeks. Want of union is a rare event.
_Treatment._--In the majority of cases of unilateral fracture after
reduction, the fragments can be kept in apposition by closing the
mouth and keeping the lower jaw fixed against the upper by means of a
four-tailed bandage (Fig. 255). Care must be taken that the posterior
tails of the bandage do not pull the mandible backward. Additional
security may be given by a light poroplastic or gutta-percha splint
fitted to the chin, the vertical portion passing well up the ramus of
the jaw. After a few days the apparatus is removed, the patient is
encouraged to move the jaw, and massage is employed. The mouth must be
regularly cleansed by an antiseptic mouth-wash, or by a spray of
hydrogen peroxide.
[Illustration: FIG. 255.--Four-tailed Bandage applied for Fracture of
Mandible.]
In certain fractures implicating the body of the jaw, and particularly
when bilateral, the co-operation of the dentist is necessary to obtain
the best results. After the fragments have been coapted, a plaster
impression is taken of the jaw and teeth, and from this a silver frame
is cast which surrounds but does not envelop the teeth. This frame is
then applied to the fractured jaw, and restrains movement of the
fragments without interfering with the action of the jaw (W. Guy).
The use of an intra-oral frame obviates the necessity of wiring the
fragments.
Even in badly united fractures the original contour of the bone is
eventually restored by the movements of the tongue moulding it into
shape.
AFFECTIONS OF THE TEMPORO-MANDIBULAR ARTICULATION
#Dislocation of the Mandible.#--Dislocation of the lower jaw may be
unilateral or bilateral. The bilateral form is the more common, and is
met with most frequently in middle life, and in females. The liability
to dislocation is greatest when the mouth is widely open--for example,
in yawning, laughing, or vomiting--as under these conditions the
condyle, accompanied by the meniscus, passes forwards out of the
glenoid cavity and rests on the summit of the articular eminence. If,
while the bone is in this position, the external pterygoid muscle is
thrown into contraction, it pulls the condyle forward over the
eminence into the hollow beneath the root of the zygoma, and the
contraction of the masseter and temporal muscles retains it there.
Muscular contraction is therefore an important factor in its
production.
Dislocation may be produced also by a downward blow on the chin, by
the unskilful introduction of a mouth gag, particularly while the
patient is anaesthetised, or even in the attempt to take a big
bite--say, of an apple. The dislocation that results from such causes
is usually unilateral.
In some persons the ligaments of the joint are unnaturally lax, and
dislocation is liable to occur repeatedly from comparatively slight
causes--_recurrent dislocation_.
_Clinical Features._--The appearance of a patient suffering from
_bilateral_ dislocation is characteristic. The mouth is open, the jaw
fixed, and the chin protruded so that the lower teeth project beyond
the upper. The patient has difficulty in swallowing, and the saliva
dribbles from the mouth. As the lips cannot be approximated, the
speech is indistinct and guttural. Just in front of the auditory
meatus a deep hollow can be felt, and in front of this the condyle
forms an undue projection. The coronoid process is displaced below and
behind the zygomatic (malar) bone, and may be felt through the mouth.
The contracted temporal muscle forms a prominence above the zygoma.
In _unilateral_ dislocation the deformity is the same in character,
but is less marked, and in mild cases its cause is liable to be
overlooked. In most cases the chin deviates towards the sound side.
_Treatment._--In recent cases, reduction is usually easily effected.
The patient should be seated on a low chair or stool, an assistant
supporting the head from behind. The surgeon, standing in front,
places his thumbs, well protected by a roll of lint, far back on the
molar teeth, and with his other fingers grasps the body of the jaw.
Pressure is now made downwards and backwards to free the condyles from
the articular eminence, and to overcome the tension of the temporal
and masseter muscles, and as this is effected the tip of the chin is
carried upward, while the whole jaw is pushed directly backward. The
condyle slips into position, sometimes with a distinct snap. When
difficulty is experienced in levering the condyle from its abnormal
position, a cork may be placed between the molar teeth on each side to
act as a fulcrum. After reduction the jaw is fixed by means of a
four-tailed bandage for a few days. The patient is warned to avoid for
some weeks opening the mouth widely.
_Old-standing Dislocation._--It sometimes happens that, from having
been overlooked or neglected, the dislocation remains unreduced. In
such cases the movement of the jaw is in time partly restored, and the
patient acquires sufficient control of the lips to be able to
articulate intelligibly and to prevent dribbling of saliva. The power
of masticating the food, however, remains impaired. The hollow behind
the condyle and the projection of the chin persist. Reduction by
manipulation is seldom possible after the dislocation has existed for
more than three months, but it has been effected as long as ten months
after the accident. Several attempts at reduction should be made at
intervals of two or three days, and if these fail recourse may be had
to operation. As the masseter and internal pterygoid muscles have
assumed a vertical position and become shortened, they form an
obstacle to reduction, and to overcome their action it is necessary to
separate them from their insertion to the ascending ramus of the bone
through an incision carried round the angle. If the adhesions about
the dislocated condyle are then separated, reduction can be effected
(Samter). In some cases it is necessary to excise the condyle to
restore movement.
_Internal Derangements of the Temporo-mandibular Joint._--The
intra-articular cartilage is liable to be displaced by excessive
traction exerted on it by the external pterygoid muscle during some
sudden movement of the joint, particularly in closing the mouth.
There is acute pain in the region of the joint, the teeth on the
affected side cannot be brought into apposition, so that mastication
is interfered with, and the patient is conscious of something locking
inside the joint. The joint is tender to the touch, but there is no
external swelling. Replacement is effected by keeping up firm pressure
at the back of the condyle with the mouth open, and slowly closing the
jaw. If recurrence takes place repeatedly, the disc may be sutured to
the periosteum (Annandale), or excised (Hogarth Pringle).
#Arthritis# of the temporo-mandibular joint occurs in two forms,
non-suppurative and suppurative.
The _non-suppurative_ form is usually due to gonorrhoeal infection,
and as a rule is bilateral. The patient complains of neuralgic pains
shooting towards the ears and temples, and of pain in the joint on
movement. The jaw is therefore kept fixed, usually with the mouth
slightly open and the chin protruded. Mastication is impossible, and
the speech is indistinct. There is effusion into the joint, and a
swelling may be detected in front of the ear. The inflammation may
subside and movement restored, or fibrous ankylosis may ensue.
The _suppurative_ form may be due either to direct spread of infection
from adjacent parts, as, for example, in middle ear disease,
suppurative parotitis, or pyogenic affections of the mandible, or it
may be part of a general pyaemic infection, as sometimes occurs after
exanthematous fevers and in gonorrhoea. The clinical features are
similar to those of the non-suppurative form, but the signs referable
to the joint are often masked by those of the primary lesion. When the
pus originates in the joint, it may point either towards the skin or
into the external auditory meatus through the petro-tympanic
(Glaserian) fissure. The joint is usually completely disorganised and
ankylosis results.
#Tuberculous arthritis# is rare, and is usually secondary to disease
of the mandible, the temporal bone, or the middle ear. It leads to
destruction of the joint and ankylosis. It is treated by incision and
scraping, or by excision of the condyle.
#Arthritis deformans# is a comparatively common affection, and is
generally bilateral. In the earlier stages the condyle is usually
hypertrophied and distorted, and the glenoid cavity is correspondingly
broadened and flattened, and in time may be filled up by new bone.
Osteophytic outgrowths form around the joint and lead to fixation or
locking. The enlarged condyle may be felt in front of the ear, and
there is pain and cracking on movement; the pain is worst at night and
in wet weather. The jaw is usually depressed and the chin protruded.
The disease runs a chronic course, with occasional acute
exacerbations. Excision of the condyle may be advisable when
non-operative measures have failed to give relief. In the later
stages, the condyle, together with the meniscus, may be worn away and
completely disappear.
#Closure or Fixation of the Mandible.#--_Temporary fixation_ is due to
spasmodic contraction of the muscles of mastication, particularly the
masseter. This may be symptomatic of some inflammatory condition in
the vicinity, such as a pyogenic affection of the lower jaw--for
example, that associated with a carious root or an unerupted wisdom
tooth, or with parotitis or tonsillitis. In such cases the spasm
passes off on the removal of the cause. It is occasionally a
manifestation of hysteria. The administration of a general anaesthetic
and the introduction of a wedge or separator is usually necessary to
confirm the diagnosis and, it may be, to permit of operative measures,
such as the extraction of a wisdom tooth.
Muscular fixation may be due to rheumatic or syphilitic myositis, and
this is sometimes followed by fibroid degeneration of the muscles,
rendering the fixation permanent.
_Permanent fixation_ may be due to a variety of causes. Fibroid
degeneration of muscles following myositis has already been mentioned.
Much more frequently it results from cicatricial contraction of the
soft parts of the face or mouth following such conditions as cancrum
oris, ulceration, or burns. Fixation following upon prolonged
immobilisation after fracture or dislocation, or any of the forms of
arthritis or suppurative or tuberculous disease of the adjacent
portions of the mandible, is also met with. The ankylosis may be
fibrous or osseous, and may be intra- or extra-articular.
The _clinical features_ vary with the degree of separation of the
jaws. There is always some deformity, and more or less interference
with mastication and speech. The patient usually feeds himself by
pushing small portions of bread or meat with the fingers through some
gap between the badly opposed and badly formed and preserved teeth. As
the patient is unable to keep the mouth clean, particles of food lodge
and decompose there, causing irritation of the mucous membrane, caries
of the teeth, and foetor of the saliva and breath. When osseous
ankylosis occurs in childhood, it leads to _arrest of development of
the mandible_, which is small and markedly receding, so that the teeth
do not oppose those of the maxilla (Fig. 256).
[Illustration: FIG. 256.--Defective development of Mandible from
fixation of jaw due to tuberculous osteomyelitis in infancy.]
_Treatment._--When the cause of the fixation is in the joint itself,
the best treatment is to resect one or both condyles.
When the fixation is due to cicatricial contraction of the soft parts,
mobility is best restored by forming an artificial joint well in front
of the cicatricial tissue, as suggested by Esmarch.