solution. Some depend on the direction in which the arterial
blood is flowing and allow for that accordingly. But in any
case our object is to reach the periodontal membrane which
lines the alveolus of the tooth to be extracted.
As we have
already stated, the success of our methods depends on a few
important points :
1. Knowledge of the nature of the bone.
2 . The nature of the soft tissues involving the gum and blood-
3. The confidence in our anaesthetic solution and its osmotic
4. The mechanical pressure to be applied with the syringe.
Although we have separated these points in order that they
may be appreciated, they become one in the application of the
The examination of the bone of the jaws in detail is recom-
mended. Take sections at various parts.
We shall find in the upper that the teeth lie in the outer
portion of the bone, right round from wisdom to wisdom teeth,
with the exception of the inner roots of bifurcated bicuspids
and the palatine roots of the molars. Therefore it is of no use
to inject on the inner or palatal side excepting at the gum margin,
which is the only part likely to reach the alveolus and the palatine
In the lower, the teeth lie near the front portion of the bone
as far as the canines, the bicuspids lie deeper at the apices, the
molars lie towards the centre, and are difficult to reach.
There is a great difference between the upper and lower jaws.
The upper is more favourable for successful local anaesthesia,
as the bone, although more solid generally in the alveolar region,
t( J 8 OPERATIVE DENTAL SURGERY
is more porous and admits of the transmission of the anaesthetic
effect. Moreover, the gum is thicker and will hold the solution
better. The lower jaw has a thick outer or cortical plate which
is very dense, almost like ivory, but there are tiny perforations
about the septa between the necks of the teeth; the gum is
thinner than in the upper, and the face of the outer surface is
concave so that the needle cannot travel down as it can in the
upper. The path of the injection should be down the centre
of the axis of the root of the tooth where the bone is necessarily
thinnest (see Fig. 45). The use of a straight needle is all that
is usually necessary, and if we realize the direction that the
anaesthetic should travel we shall have success. The gums
vary in their nature, some tissues are thin and anaemic, others
FIG. 45. SECTIONS OF BONE.
A, Lower twelve-year molar; B, upper canine; C, lower second bicuspid,
centre of socket; D, lower second bicuspid, side of socket.
are thicker and flocculent in appearance, and some are swollen
and congested. If an abscess is indicated either by swelling or
a fistulous opening it should be avoided and the injection made
around it. It requires the practice which comes from experience
to effect the entrance of the needle in the varying conditions of
the gums. If the gums are healthy and dense the anaesthesia
will probably be better, as the pressure will carry the solution
well in. In loose tissues difficulty will be found to retain it.
We must observe the face of the gum and avoid superficial
veins, which can be seen. If the needle is carried up the face
of the gum very far, care must be taken to tighten the soft
tissues which form the junction of the lips and cheeks, as the
solution will quickly disappear and be useless, whereas we want
it directly against the bone. Care also must be taken not to
LOCAL ANESTHESIA OR ANALGESIA igg
push the needle against the bone or the point of the needle may
break. The rustless steel needles supplied by Messrs. De Trey
and Co. are excellent, they are fine in size and easily pene-
trate the gum, and in the lower are more likely to conduct the
solution without leakage. Copper-headed needles are also good,
because they do not jamb in the nozzle. It is only necessary
to well inject on the labial and buccal surface of the gums,
starting at a point about an eighth to a quarter of an inch from
the gum margin, which allows the solution to travel round the
gum about the neck of the tooth to reach the periodontal mem-
brane, which will then conduct it down the alveolus. In the
upper the bone is usually thin at the apical part of the roots, and
advantage can be taken of this. The tongue side of the mandible
and also of the palate is near fairly large bloodvessels. We must
observe the positions of these. This risk can be avoided by
using the external side only. In the palate there are the anterior
and posterior palatine canals and also the palatine blood-supply
which ramifies the palatal surface. On the external surface of
the lower we should remember the position of the mental foramen.
The precaution must be taken of expelling any air that may
be in the syringe before injecting, as a bubble of air which might
possibly get into a bloodvessel, especially a vein, might cause
serious trouble, and if it reached the heart would probably cause
alarming syncope. The best way is to tap the syringe in an upside-
down position and then squirt a little solution out of the syringe.
Pressure in injecting must be applied according to the density
of the tissues. Undue pressure sometimes results in a white
zone on the face in the region of the infra-orbital foramen in
the upper, and the same phenomena in the lower, in the region
of the mental foramen, and if it is very intense will anaesthetize
the corner of the lips.
Many practitioners make a practice of giving every patient,
when using cocaine, a dose of stimulant to act as a carminative.
Validol is an excellent one, tincture of strophanthus with car-
damoms is a powerful one (see end of chapter on Stimulants).
If a patient is very nervous, or of a weak type, it is wise to
administer a stimulant such as Messrs. Parke, Davis and Co.'s
Nitroglycerine Elixir, Black's Cardiactis, or Bowen's Anti-shock.
The area of the gum for injection must be rendered aseptic
before attempting to place the needle into it. Tincture of
iodine or Dentalone are useful for this purpose, particularly the
200 OPERATIVE DENTAL SURGERY
former. If the mouth is not a healthy one the patient should
be advised to use a mouth- wash, night and morning, of peroxide
of hydrogen, or Camphenol, three or four times a day, for a day
or so. Peroxide of hydrogen ought not to be used at the time
of injection because of the danger of driving tiny bubbles of gas
into the tissues.
Some patients will exhibit signs of faintness and even collapse,
partly under psychological imagination, the physiological action
of the solution on the nervous and circulatory system, or from
shock. Fortunately these cases are not frequent, but the
operator must be prepared for them.
The symptoms of cocaine poisoning are not often seen now
that the methods of injection are better understood. Large
round beads of perspiration, of a characteristic type, are seen
on the forehead, the patient feels dizzy and faint, with rapid
and feeble pulse, difficult breathing, lips blue, and pallor. If
the symptoms are not attended to they will become alarming,
with respiratory spasms, and syncope following.
The first treatment is to administer a quickly acting stimulant
such as aromatic spirit of ammonia, dose, 30 to 60 minims in
water. Tincture of strophanthus is useful but very slow in
action, dose, 2 to 5 minims in water. As this is such a
powerful agent it is better mixed in a quantity, and the use
of fresh proprietary restorative compounds obviates the
difficulty. A second dose should not be given under half an
hour afterwards. Push the patient's head well down between
the knees. Postural treatment is very effective by placing the
patient in a horizontal position with the head lower than the
feet in order that the blood will gravitate to the head and reach
the medulla (see Chapter IX.). If the symptoms become severe
inject ^ grain of strychnine sulphate; this is supplied in con-
venient capsules or ampoules for the purpose. Amyl nitrite
is useful in threatened syncope. It is a powerful vaso-dilator,
administered usually by inhalation: dose 2 to 5 minims. It is
supplied in glass capsules covered with silk, which are crushed
between the fingers to release the vapour; 3-minim capsules are
convenient (Martindale's). It is largely employed as a restora-
tive in bad cases of fainting.
Death through overdose of cocaine is by asphyxia, therefore
attention must be given to the breathing, and if necessary artificial
respiration must be performed. Inhalation of oxygen is useful.
LOCAL ANESTHESIA OR ANALGESIA 201
It is not prudent to attempt injection in a very septic mouth
or if there is a severe abscess, especially in the lower jaw in
the wisdom tooth region. There is extreme danger of severe
secondary infection occurring both from the vaso-constricting
action of the solution and the pressure from the syringe driving
pus into the deeper tissues. The administration of nitrous
oxide gas is suitable for such cases. If this is not possible
such cases could be dealt with by the application of a topical
solution of an anodyne. The following method, although an old
one, is well worth consideration. It has constantly been used
by the writer for twenty years with success for the extraction
of teeth in young children, elderly people, and heart patients,
and for the septic lower molars already described.
The employment of the method depends entirely on the gum
being thoroughly dried. This is done with large pieces of
amadou. The neck of the tooth and well around the whole
region of the roots is painted with I or 2 minims of :
Liniment of iodine . . . . . . . . 2 parts.
Tincture of aconite . . . . . . . . i part.
This is applied with a small piece of amadou about |- or J inch
square. It is then followed by painting, in the same way,
2 or 3 minims of the following mixture :
Liniment of capsicum . . . . 3 drachms.
Oil of cloves . . . . . . . . . . 20 minims.
Oil of peppermint . . . . . . . . 20 ,,
Absolute alcohol . . . . . . . . 2 drachms.
The patients are directed to keep their mouth open and not to
swallow. When they wish to do so they are to rinse their mouth
out with warm water, once only. In the meantime we prepare
a hot mouth-wash in a tumbler. Boboeuf's Phenol Sodique,
which contains some oil of tar, is an excellent preparation for
syringing painful septic sockets where severe pain is caused
by the inflamed conditions. If used quite hot and discharged
well into the socket with a fairly large syringe, immediately
after the extraction it gives almost instant relief. The suitable
strength for this purpose is a teaspoonful in a third of a tumbler
of hot water or less water if it is very painful. This is not a
suitable mouth-wash for syringing if cocaine or novocain has
been injected, because there is alkali in it. An alkali will preci-
pitate an alkaloid. The best mouth- wash for such cases is
carbolic acid i in 120 to 200 parts, or per cent. Cam phenol.
THE ADMINISTRATION OF NITROUS OXIDE GAS ALONE,
OR IN COMBINATION WITH AIR OR OXYGEN, FOR
NITROUS oxide gas has been used in dentistry for the last sixty
years or more. It has gone through a strenuous investigation
by many eminent men. Although it went through periods of
popularity and for a time was in rivalry with local anaesthesia,
yet it has never been abandoned or condemned, but has held
a firm grip in dental surgery for short operations. The shortness
of the available anaesthesia was the main drawback or limitation
to its use. It was a matter of controversy as to whether nitrous
oxide was really a true anaesthetic. Many medical men con-
tended that it produced anaesthesia by partial asphyxiation, and
was therefore a dangerous agent. This view was favoured by
them because, being well versed in the administration of the
heavier anaesthetic vapours, ether, chloroform, and alcohol,
they were apt to attach too much significance to the asphyxial
symptoms which with the heavier anaesthetics are alarming in
their importance because they have the patient soaked with
a drug, whereas with nitrous oxide its effects are purely gaseous
and are eliminated quickly. The outcome of many years of
constant investigation and practical experience in thousands of
gas cases by such men as Sir Frederick Hewitt of London, and
Dr. Charles K. Teter of Ohio, has placed nitrous oxide gas in a
highly creditable and safe position as a true anaesthetic.
Dr. Teter states that the dangers of nitrous oxide are technical
only, while the dangers from all other anaesthetic agents are
pathological as well as technical.
Sir F. Hewitt, in his work on " Nitrous Oxide and Oxygen for
Dental Operations," has demonstrated beyond question that
nitrous oxide gas, N 2 O, is perfectly safe, and that the dangers
which arise from asphyxial phenomena are caused by depriva-
tion of oxygen or by mechanical obstruction.
Nitrous oxide gas is the anaesthetic par excellence for dental
THE ADMINISTRATION OF NITROUS OXIDE GAS 203
work, and its use has been well extended into general surgery
for many major operations under certain conditions. It is also
being used for producing analgesia for preparing cavities, light
anaesthesia for nerve canal work and extracting pulps.
Operating on a patient under its influence demands a different
style of operating to that of local anaesthesia because the patient
is unable to help himself or the operator, who has to see that
his work does not interfere with the patient's respiratory func-
tions. Also he has to be more alert and agile with his hands
in order to lessen the time and spare the patient unnecessary
There are, and have been through all these years, many men
who are expert at gas operations and who hold the anaesthetic
in high esteem because they know by long experience that if
skilfully administered it guarantees a painless operation. Of
course, there are cases which are exceptional, but they are
very few, and with the latest improvements in gas apparatus
these exceptions are very robust, strongly built patients of both
sexes whose thoracic capacity syphons more air into the lungs
than the anaesthetic can overcome. But even with this type
of patient it does not necessarily mean that they will not be
suitable for successful anaesthetization. Alcoholic patients, of
course, give some trouble, and it is a question whether abstaining
for a day makes matters much better.
Now there are two definite methods of administration with
nitrous oxide gas :
1. Short method, with the use of the ordinary face-piece.
2. Prolonged method, with the use of a nasal inhaler.
In general surgery, when long operations are performed, the
prolonged method is conducted with a face-piece which entirely
precludes the possibility of air getting in, and the patient can
breathe either through the nose or mouth.
The first method has been in use since gas was first used
in dentistry, although the face-piece is less cumbersome and
engulfing in appearance than those in use years ago. We
must be careful with certain types of patients or those who
have certain diseases or probable lesions from them.
The following conditions require special care in order to avoid
continued or well-marked asphyxial symptoms :
Endocarditis, or inflammation of the endocardium which is
20 4 OPERATIVE DENTAL SURGERY
the internal serous membrane of the valves and cavities of the
heart, usually caused by rheumatism and accompanied by
well-marked valvular murmurs.
Bright's disease, with albuminuria, especially after scarlet fever.
Arterio-sclerosis, a brittle condition of the arteries, which fail
to accommodate the pulsation caused by the heart's beat. This
condition throws a strain on the heart, which would be seriously
embarrassed if asphyxial strain were added under gas.
Valvular disease of the heart caused by rheumatic and other
Aortic aneurism, which is an overstrained condition of the
aorta often caused by a localized arterio-sclerosis. It is in the
nature of a tumour caused by the weakening of the arterial wall.
Goitre, an enlargement of the thyroid gland, will swell under
the influence of gas, causing a restriction or constriction of
the larynx. Exophthalmic goitre consists of enlargement of
the thyroid gland accompanied by a prominent development
of the eyeballs and an increased action of the heart.
Anaemia or bloodlessness, which is fairly common in young
Heavy tobacco smokers.
These cases also are contra- indicated with cocaine.
Assuming that the patient is fairly healthy and can come into
the surgery looking fit, there is no danger from N 2 O gas when
administered by an experienced man, but care, of course, is needed.
The apparatus and instruments for the administration of
nitrous oxide gas consist of :
Gas stand; gas bottles 25-, 50-, 100-, or 2OO-gallons capacity;
2 to 5 gallon rubber bag; tubing from bottles to bag and from
bag to face-piece ; a three-way stopcock to control gas and air ;
and a face-piece. An assortment of gags, plain vulcanite and
Hewitt's are best for ordinary cases, Brunton's gag, Buck's
gag, or any special gag that may be required. The simpler the
gag is in construction the better. No rubber pads are required
either on mouth-gags or Mason's gag; they are apt to slip
when blood is about and they are uncleanly. A wedge for
prising the mouth open, or, failing that, the handle of a pair
of forceps will answer the purpose. Mason's gag, tongue forceps,
(there are various patterns, but the smaller the blades the
THE ADMINISTRATION OF NITROUS OXIDE GAS 205
better), sponge holders for holding small sponges or swabs, and
one or two large sponges for quickly sponging out the mouth;
they must be soft and free from loose bits.
A cylinder of oxygen for inhalation, with a tube for putting
into a patient's mouth, or an aluminium funnel attached to
hold over patient's mouth, if in a horizontal position.
The patient should be instructed to remove or loosen any
tight clothing, corsets, waistbands, collar, or belts. Studs should
be taken out. Some ladies wear a tight ribbon band for orna-
ment round their necks: this simple matter might lead to the
venous blood being held back in the neck. When in the chair
the operator must see that artificial teeth, and anything loose
in the mouth, are removed. The position of the patient's head
in the chair should be in a line with the body, not far back or
too forward. If they show marked signs of nervousness, direct
them to clasp their hands, which has the effect of locking them
when going under the influence of the gas. With men, place their
feet on the floor each side of the chair. In any struggling which
might ensue there is less chance of their getting such a firm
purchase as if they were against the foot-rest.
The face-piece, which has a rubber pad around the edge,
should be well inflated with air, but not too full. Whiskers,
moustaches, and thin faces require some manipulation to prevent
air getting in at the sides. The gas cylinders should be well
turned on before the patient enters the room. The patient is
allowed to breathe through the face-piece, with air for a few
breaths, then the gas is let in and the patient is taking gas
without air; but if, after several breaths, there is any sign of
cyanosis a full breath of air now and again will rectify it. But
the gas should be without air until the patient is fully under its
influence, excepting anaemic and weak people, when, after a few
breaths of pure gas, a small percentage of air may be permitted
through the airway of the stopcock.
The administration may be summed up by a description of
the physiological action of the gas and the signs of anaesthesia.
The gas passes through the mouth, past the tonsils, the
pharynx and epiglottis, through the glottis, down the larynx,
the trachea, into the bronchi, right and left, into the bronchial
tubes of the lung substance, and then into the lobules of the
lobes of the lungs. Dr. Halliburton, in his " Handbook of
Physiology," states: "Each lung is partially subdivided into
206 OPERATIVE DENTAL SURGERY
separate portions called lobes, the right lung into three lobes
and the left into two; each of these lobes again is composed of
a large number of minute parts, called lobules. Each lobe
may be considered to be a lung in miniature. On entering a
lobule, the small bronchial tube divides and subdivides, its walls
become thinner and thinner until at length they are formed
only of a thin membrane of areolar, muscular, and elastic tissue.
At the same time they are altered in shape ; each of the minute
terminal branches widens out funnel-wise, and its walls are
pouched out irregularly into small saccular dilations called
air sacs. The air sacs or vesicles may be placed singly, but
more often they are arranged in groups or even rows. Outside
the air vesicles is a network of pulmonary capillaries spread
out. Between the air in the sacs .and the blood in the capillaries
nothing intervenes but a thin membrane. The object of the
complicated structure of the lung is to provide a very large
surface for the interchange of the gases in a compact organ.
The total surface of the inside of the lung has been variously
calculated, but it may be taken to be about 90 square metres
in the adult, or about the size of a carpet necessary to cover
the floor of a good-sized room, 10 yards by 12 yards."
The gas passes through the membranous walls on the principle
of osmosis, into the blood ; here it is taken up and held in loose
combination with the haemoglobin of the red corpuscles which
finally reach the cells of the brain, where its influence gradually
paralyzes the parts of the nervous system -the cerebrum,
cerebellum, spinal cord until the medulla is reached, when the
signs of anaesthesia indicate the limit to which we may go. If
pushed and continued, an overdose will complete the general
paralysis and death take place.
Generally speaking the stages of the action of N 2 O gas may
thus be summarized:
First stage :
Tingling in limbs.
Patient feels exhilarated and breathes more quickly and
Consciousness becoming lost.
Respirations deepen and become more regular.
Pulse fuller and somewhat quickened; the temporal
artery just in front of the ear is a convenient pulse.
Hearing becomes] acute.
THE ADMINISTRATION OF NITROUS OXIDE GAS 207
Second stage :
Patient is conscious to anything being done, but is not
really under. To attempt any extraction at this
stage would produce shock or struggling.
Patient may make movements.
Excitement may occur, especially if air is admitted.
Respiration is now deeper and quicker than normal and
Pupils gradually dilating.
Complexion is dusky.
Eyelids twitch and slightly separate.
Third stage :
Respiration becomes automatic and regular.
Stertor caused by the aryteno folds of the larynx becom-
ing approximated to one another and closing up the
airway, the second or third stertor should be the
limit of depth of anaesthesia and the gas withdrawn,
in this method.
Pulse is rapid and not so strong as in second stage.
Muscular system is relaxed; patient's arm when raised
will flop down when released.
Conjunctival reflex of the eye has gone; test this by
touching it with the ball end of the finger.
Pupil well dilated usually.
The patient's face is distorted, the eyeballs rotate, or
there is a vertical nystagmus or turning up of the eye-
balls. Patient is also cyanosed, badly in some cases.
The signs of anaesthesia are stertor, flaccidity of the muscles,
and automatic breathing. Neither of these signs is absolutely
conclusive, but taken collectively they are reliable ; but the anaes-
thetist by constant practice recognizes the phenomena when
they arrive. If the gas is unduly pushed there will be jactita-
tion, convulsive movements, and opisthotonos or arching of the
back. These phenomena are very inconvenient to the operator.
The operator commences his operation and must carry it out
quickly, as there are only thirty seconds of available anaesthesia.
He must be careful not to push the tongue back or force the
lower jaw downwards, both of which will embarrass the breath-
ing. He must also be careful in operating on the lower jaw not
to lacerate the soft tissues at the base of the tongue, as that
ao8 OPERATIVE DENTAL SURGERY
organ swells up considerably under gas. He must also be*
prepared for a tooth springing out suddenly and lodging in the