1. The document discusses local anaesthesia equipment and techniques used in dentistry. It describes the components of local anaesthesia syringes, needles, and cartridges. 2. Various local anaesthesia techniques are covered, including infiltration, block, and topical anaesthesia. Infiltration anaesthetizes terminal nerve fibers, while block anaesthetizes the main nerve trunk. 3. Topical anaesthesia is described as surface anaesthesia for mucosa or skin using physical or chemical methods. Its effectiveness depends on the site of application and adequate time allowed.

1. LOCAL ANAESTHESIA
and EXODONTIA
Dr. Reda F. Elgazzar
BDS, MSC, (Eg) Phd (UK)
Oral and Maxillofacial Surgery Dept.
College of Dentistry, King Faisal University, KSA.

2. LECTURE NO 4
1. LOCAL ANAESTHETIC
EQUIPMENTS
2. INTRODUCTION TO LA
TECHNIQUES

3. Outline

LA equipments
 LA Syringe, Needle, Cartridge



Position of the operator and the patient
Infection control during LA procedures
LA Techniques:



Infiltration
Block
Topical



Methods
Technique for successful TA
Importance and effectiveness

4. The equipment used to deliver LA solutions
comprises three components:
• Needle
• LA Cartridge
• Syringe
• Topical A.

5. LA Needle
They are disposable

Components:
shank, hub, bevel

Dimensions:
length: Ultrashort, Short & Long
width (gauge): 27 (0.4) & 30 (0.3)


Package: blisters, cans
Hazards: handling, injury

6. LA cartridge
• Components: Cylinder, plunger, diaphragm
• Types: Standard – Self aspirating, plastic, Glass
• Contents: LA, VC, Vehicle, preservative.
• Volume: 1.8, 2.00 & 2.2 ML.

7. Packaging

8. Important information

9. LA Syringe



Usually non-disposable
Components: threaded hub, Barrel, Plunger
Types: According to:
•
•
•
Loading: Side (lateral) and breach (basal)
Aspiration: Non-aspirating, Manual aspirating &
Automatic aspirating
Material: Metallic, Plastic, Glass

10. LA Syringes

11. Specialized syringes
•
•
•
Intraligamentary syringe:
ultra short needle needed,
LA cartridge is protected
Intraosseus syringe: narrow
surgical drill needed
Jet injection syringe: No
needle needed

12. Assembling the syringe system




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Ensure syringe has been sterilized
Ensure the needle container seal is
intact
Break the seal by rotation
Screw needle to hub
Check the LA cartridge contents:






Expiry date
Cloudiness
Cracking
Air bubbles
Load the syringe with cartridge
Ensure free flow of LA

13. Holding the syringe



Hold the barrel rest with the
index and middle fingers of
the dominant hand and the
thumb rest with any part of
your thumb.
The syringe should be below
the vision level
The other hand (dental
mirror) should reflect and
stretch the mucosa and
identify the landmarks

14. Operator and patient position

Operator position:
seated or standing (depending
on the procedure), to the right
side of the patient except:
R IANB and R GPNB, R
Lingual infiltration on front of
the patient.

Patient position:
Semi supine (30-45 degree)
position is the ideal position
for LA, Supine position if
there is history of fainting

15. Dismantling the syringe system

Remove needle either by:



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Needle forceps
Finger protector
Single-handed pick up
Disposable syringe has a built-in needle
guard
Place the needle and the glass
cartridge in labelled sharps
container (Orange)
Return the syringe for washing
and autoclaving

16. Prevention of cross infection with LA




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Never use the same needle on more
than one patient
Never use the same cartridge on
more than one patient
Ensure non disposable syringes are
sterilised
Never re-use disposable syringes
Avoid contaminated needle stick
injuries by proper dismantling the
syringe system

17. INTRODUCTION TO LA
TECHNIQUES

18. LA Techniques
The transmission of nociceptive impulses from tooth to
brain can be blocked at any point on the neural
pathway from the dental pulp to the cerebral cortex.




Topical anaesthesia (T A): anaesthetise the nerve endings
in surface mucosa.
Infiltration Anaesthesia (I A): anaesthetise the terminal
nerve fibres of one or more nerve (s).
Block Anaesthesia (B A): anaesthetise the main nerve
trunk.
Spinal Anaesthesia (SA): anaesthetise the lower half of the
body.

19. LA Techniques



The choice between infiltration and regional
block techniques, as far as dental anaesthesia is
concerned, is governed by barriers to diffusion
(Bone Density and Porosity).
Maxilla: I A is successful
Mandible: I A is not successful

20. LA techniques
Topical: Physical, Chemical,
Parenteral: Conventional, Supplementary

21. Topical Anaesthesia


Surface anaesthesia for mucosa or skin
Importance:
•
•
•
•

Reducing pain of LA needle penetration
Reducing discomfort of venepuncture
Therapeutic e.g.. Ulcers
For superficial soft tissue manipulation
Effectiveness:
•
•
•
TA is more effective with non-keratinised mucosa
TA anaesthetise only 2-3 mm mucosal depth
It can mask superficial needle penetration only, but
not pain due to rapid injection or cold LA.

22. Topical Anaesthesia

Methods of TA:

Physical:
•
•
•

Refrigeration (Ethyl Chloride)
Disadvantages: Difficult application,
Inflammable, GA, however,
Still used as a vitality tester for teeth.
Chemical:


Gel, Ointment, Spray
• E.g. Lignocaine (2% gel, 5 % ointment,
10% spray and Benzocaine (20% gel)
Jet injection: LA is forced through the mucosa
without needle using jet injector (1 cm depth)
• Disadvantages: expensive, off-putting,
noisy, hazardous

23. Technique for successful TA




Clean and dry the mucosa to
remove any potential barriers
(mucous, debris)
Applied on limited area to
avoid systemic absorption and
unnecessary numbness (Gel is
better)
Leave for enough time (2 mn)
Skin and keratinised mucosa
needs more concentrated TA
for a longer time

24. References
1.
2.
Meechan, et al., Hand book of local
anaesthesia, 1998.
SF Malamed: Pain and anxiety control for
the conscious dental patient, 1997.

25. 
1.
2.
3.
A. Choose the best answer:
a Vasoconstrictor is added to the local anaesthesia (LA) in order to:
A.
Enhance the absorption of the LA
B.
Make the medium more alkaline
C.
Prolong the contact of the LA with the nerve fibres
D.
Xa and c
E.
All of the above
All of the following are contained in the sphenopalatine fossa
except:
A.
Maxillary nerve
B.
Terminal branches of the Maxillary artery
C.
XNerve to medial pterygoid
D.
Sphenopalatine ganglion
E.
b and c
The main principal of the gate control theory of pain is based on:
A.
That each receptor is responsible for a specific kind of sensation.
B.
The central convergence of the nerve fibres.
C.
XThat the higher centres have an inhibitory effect on the lower
sensory nuclei.
D.
That the thick nerve fibres (for touch and pressure) have an
inhibitory effect on the nerve fibres of small diameter (for pain).

26. B. Write True or False where is applicable:

4.
To do cavity preparation for amalgam filling in lower 2nd molar, it is
important to anaesthetize the long buccal nerve .F
5.
To do endodontic treatment in upper 2nd molar, it is important to
anaesthetize the greater palatine nerve. F
6.
Local anaesthetic agents of Amide type are mainly hydrolysed in liver
where as Ester type agents are hydrolysed in plasma. T
7.
The bony infiltration anaesthesia is mainly dependent on the density of
jawbone.T
8.
The ideal LA agents should have rapid onset and long working time. T
9.
Most LA agents have a vasoconstrictor action.F

27. A. Answer the following questions:
10. Maxilla is supplied by the 3……………….part of the …MAX……….......artery, mandible is supplied
by the …1………….. part of the ………….….artery and most masticatory muscles are supplied
by the…2 ……part of ………..…artery.
11. Enumerate 4 branches of the External Carotid artery that supply the orofacial structures:
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…………………………………………………………………………
…………………………………………………………………………
…………………………………………………………………………
…………………………………………………………………………
12. Enumerate the different central nuclei that relate to the Trigeminal Nerve

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
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…………………………………………………………………………
…………………………………………………………………………
…………………………………………………………………………
…………………………………………………………………………..
13. Mentioned the terminal nerves to be anaesthetized for extraction of Upper 1st molar

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…………………………………………………………………………
…………………………………………………………………………
…………………………………………………………………………
…………………………………………………………………………..
14. Mentioned the terminal nerves to be anaesthetized for extraction of Lower 1st molar

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…………………………………………………………………………
…………………………………………………………………………
…………………………………………………………………………
…………………………………………………………………………..
15. The main motor nerve of the facial muscles is…FACIAL………………..nerve, and for the
masticatory muscles is…MANDIBLE…………………. nerve.

28. Good Luck