AND TEETH?
LOCAL INFILTRATION
FOR ALL UPPER TEETH, THE LOWER INCISORS AND CANINES, AND ALL DECIDUOUS TEETH Infiltrate the solution outside the periosteum, near the apex of the tooth. This is where its nerves enter the bone, so this is your target.
Labially is his upper jaw. Inject at the reflection of the mucous
membrane where it forms the base of the sulcus, as in A, Fig. Inject 1- 2ml of solution, or about half a cartridge. The tip of your needle should come to lie opposite the tip of the root of the tooth you are going to extract. For front teeth insert the needle in line with the tooth. This is impossible with molars, so, if you want to anaesthetize a patient’s third molar, insert the needle over his second molar, and aim it obliquely so that its point comes to lie over the root of his third. If you move the point of the needle fanwise, as in D, very carefully, you can anaesthetize 2 or 3 teeth without removing it.
When you inject his upper molars (D), feel the gum on the outer surface of his upper back teeth. The crest of bone jutting down from above is his infrazygomatic crest. Insert your needle immediately behind this crest, distal to his second molar.
Push your needle in 2 cm, as far as it will go, and inject 2 ml of solution. Move it as fanwise as you inject. This is also called a tuberosity block.
Palatally in the upper jaw Inject at the points marked “X”
about 1 cm from the tooth half way between the edge of the gum, and the mid line, as in B, Fig. This is a shallow injection because his palate lies close below a patient’s mucous membrane. Inject just enough solution to make his gum go white. You will not be able to inject much, and you will have to press quite hard.
Labially in a patient’s lower jaw. Hold his lip out of the way
so that you can see the sulcus clearly. Insert the needle next the chosen tooth, so that its point lies against the outside of his mandible, level with the tip of the root. Inject half a cartridge.
Lingually in the lower jaw. Insert the needle a short distance
at the point where the mucosa is reflected off the lingual side of his alveolus, as in A, Fig. You may have to hold his tongue out of the way to see the floor of his mouth. Inject about a quarter of a cartridge. There will be a small swelling, which will quickly disappear.
THE LOWER PREMOLARS Labially do a mental block like this:
Pull down the patient’s lower lip. Use the tip of your index finger to feel the labial surface of his gum as it turns upwards to join his cheek just posterior to his first premolar tooth. You should be able to feel his mental nerve as it comes out of the mental foramen in his mandible.
Inject from behind, as in F Fig. Pull the corner of the patient’s mouth out of the way. Tilt the needle medially between his first and second premolars. Aim to place the needle just outside his mental foramen. This is half way between his gingival margin and the lower border of his mandible. As a person gets older, his mandible is absorbed, so that his mental foramen comes to lie nearer the upper border of this mandible. Inject 2 ml of solution. If necessary, repeat the procedure on the other side.
Try not to enter his mental foramen, because you may injure the vessels that come out of it, and so cause a large haematoma.
Lingually inject his premolars in the same way as for his lower incisors
and canines.
LOWER MOLARS Do an inferior alveolar and lingual nerve block, as described below.
Fig: INFILTRATING THE LOWER GUMS. A, infiltrating the lingual and B, the labial gum. RIGHT INFERIOR ALVEOLAR AND LINGUAL NERVE BLOCK:-
Landmarks The secret of success is to visualize where the patient’s
mandibular foramen is, and to aim the tip of a 42 mm needle at it. As usual, the details are all important.
Adjust the headrest, so that when the patient’s mouth is wide open, the occlusal plane of his mandible is horizontal, as in D, Fig. When you are learning, use a dental stick dipped in gentian violet to draw a line QR on the mucous membrane of the inside of his cheek in the line of the occlusal surfaces of his lower teeth. If he has a denture, draw it with this in place. If marking it makes him retch, anaesthetize his mucosa first.
Feel the anterior and posterior borders of the ascending ramus of his mandible between the thumb and index finger of your left hand, as in C. Make sure that your index finger is as far up his mandible as it will go. The tips of your fingers should lie at either end of line QR. Aim at the mid point between them – usually 2 cm behind point R. Rest the syringe on the occlusal surfaces of the teeth.
Fig: INFILTRATION ANAESTHESIA FOR THE TEETH. A, when you infiltrate a patient’s gum, put the needle into his buccal sulcus, make the bevel face his periosteum and inject just outside it. B, to anaesthetize his palatal gums inject at the point marked “X”. C, infiltrating the palatal gum of his first molar. D, infiltrating the buccal aspect of his third molar (tuberosity block). E, infiltrating the gum of his lateral incisor. F, blocking his mental nerve. His mental foramen lies on a vertical line between his 4th and 5th teeth, and in a young person is half way up his
The block Now you know the landmarks, put your left index finger into
the patient’s mouth, above his lower third molar, as in the upper diagram in Fig. you will feel a depression in the bone immediately above and behind it (retromolar fossa). Behind this you will find a ridge (the oblique line), on the inner surface of his mandible.
Ask him to open his mouth even wider.
Insert the needle, as described above, immediately medial to the oblique line, 1 cm above the patient’s third molar. At first, place the syringe in the line of the body of his mandible. This is position ”X”. As you push the needle in 2 cm, move the barrel of the syringe across his teeth, so that it lies over his opposite premolar. This is position “Y”. As you move the needle, keep it in contact with his teeth all the time. If he has no teeth, keep it carefully horizontal in his mouth. As you do so, you will feel the needle pass through the buccinator muscle. As it goes through, inject 0.5 ml of solution.
Push the needle 2.5 cm further in until it reaches the medial surface of the ramus of his mandible. Inject 2.5 ml here to block his inferior alveolar nerve. If you reach bone at a lesser depth, your needle is too far lateral (needle A in Fig). If you feel no bone, it is too far medial (needle B).
After you have withdrawn the needle, inject the last 1 ml of solution into his buccal sulcus, just above the crown of his third molar tooth. This will block his buccal nerve, as it lies on the inner surface of his buccinator muscle.
The latent period lasts 10 minutes. The whole of one side of the patient’s face will feel heavy, and his lower lip will feel dead on that side.
If anaesthesia of his canine is not complete, infiltrate his gum, or
block his mental nerve.
CAUTION! (1) Don’t’ push the needle completely into the patient’s tissues, if it breaks you will have great difficulty removing it. (2) Before starting to extract a tooth, press the beak of the forceps hard on both sides of the tooth. If he feels pain, give him another injection.
Fig: INSERTING THE NEEDLE TO BLOCK THE INFERIOR ALVELAR NERVE. Notice the position of the point of the needle.