Dental Syringe Mechanism and Types

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Questions and Answers

What is the primary reason aspirating dental syringes are considered the standard of care?

They can aspirate blood when intravascular. (correct)

They allow for quicker injections.

They are less expensive to manufacture.

They are more comfortable for patients.

What component of the dental syringe is responsible for penetrating the rubber stopper of the cartridge?

The plunger

The harpoon (correct)

The needle adaptor

The hub

Which type of syringe allows for needle-less injection?

Safety syringe

Jet syringe (correct)

Pressure syringe

Aspirating syringe

Which part of the dental needle determines its angle of entry?

Bevel Signup and view all the answers

What is the main feature of a safety syringe?

They include a self-contained injection unit. Signup and view all the answers

What type of dental needle length is most frequently used for intraoral injections?

Short and long Signup and view all the answers

Which type of dental syringe uses negative pressure applied to the thumb ring for aspiration?

Aspirating syringe Signup and view all the answers

What is the purpose of the elasticity of the rubber diaphragm in anesthetic cartridges?

To aid in multiple aspirations during testing. Signup and view all the answers

What is the recommended length of a long needle used for mandibular blocks?

32 mm Signup and view all the answers

Which needle gauge is recommended for injections with a high risk of positive aspiration?

25-gauge Signup and view all the answers

How deep should a long needle typically penetrate for a Gow-Gates mandibular block technique?

25 mm Signup and view all the answers

Why is it important to avoid inserting the needle to the hub?

To reduce the risk of needle breakage Signup and view all the answers

For which of the following injections is a short needle preferred?

Posterior superior alveolar injection Signup and view all the answers

What is the correct orientation of the bevel during injections near the periosteum?

Toward the bone Signup and view all the answers

What is the purpose of the dental cartridge in dental procedures?

To hold local anesthetic solution Signup and view all the answers

Which gauge needle is generally not recommended for supraperiosteal or block injections?

30-gauge Signup and view all the answers

Study Notes

Dental Syringe

Dental syringes are the standard of care due to their ability to aspirate blood if the needle tip is intravascular.
The armamentarium includes 4 parts: syringe, needle, cartridge, and preparation.
Syringe parts include thumb ring, finger grip, piston rod, barrel, harpoon, and threaded tip

Parts of a Dental Syringe

Threaded fitting for the needle
Slit for inspecting the tubular vial
Coupling for the plunger of the tubular vial
Barrel
Finger grip
Plunger
Handle

Self-Aspirating Uses

The elasticity of the rubber diaphragm in the anesthetic cartridge allows for multiple aspirations easily.

Aspirating Syringe

The needle adaptor is sometimes inadvertently discarded with the disposable needle.
The harpoon is a sharp tip on the piston that penetrates the thick silicone rubber stopper at the cartridge's other end.

Pressure Syringes

Used for PDL (intraligamentary) injections.

Additional Syringe Types

Second generation PDL Syringes
Jet Syringes: needle-less injection, forces liquids through small openings (jets) at very high pressure, penetrates skin and mucous membrane
Syrijet is the most popular jet syringe, holds 1.8ml cartridges of local anesthetic.

Safety Syringe

Some dental safety syringes come with autoclavable plungers and disposable self-contained injection units.
All dental safety syringes are single use items.

2-Dental Needles

Components include bevel, shank, hub, syringe adaptor, and cartridge penetration end.

Parts of a Needle

Bevel
Shaft
Gauge number
Hub

Needles Divided by Length

Dental needles are available in long, short, and ultrashort lengths.
The most common are long and short.
Lengths may vary by manufacturer, long needles are generally 32mm (1.5in) and short 20mm (1.0in).
Long needles are for mandibular blocks (20-25mm penetration depth).

Needle Breaking & Placement

Needles can break at the hub easily.
If broken, and less than 5mm of it is exposed, it's difficult to retrieve.
Long needles are usually preferred for the anterior superior alveolar (ASA)/infraorbital injections.
Short needles are preferred for posterior superior alveolar (PSA) injections, supraperiosteal injections, and tissue infiltrations.

Needle Gauge

Needle gauge refers to the diameter of the lumen(hollow tunnel).
Common gauges include 25, 27, and 30.
Larger number equates to thinner and smaller gauge.
25 and 27 gauge are most common.

Needle Gauge Recommendations

25-gauge needles are recommended for injections with high risk of positive aspiration and significant depth of penetration.
27-gauge needles are restricted to injections with minimal depth of penetration and positive aspiration risk.
30-gauge is not typically used for deeper injection.

Bevel Correct Position

The bevel should be oriented towards the bone during injections close to the periosteum.
This reduces trauma and increases patient comfort.

Dental Cartridge (Carpuke)

A glass cylinder containing local anesthetic solution.
Parts include cylindrical glass tube, stopper, aluminum cup, diaphragm.
Glass cartridges should not be autoclaved.

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Description

Explore the intricate design and functionality of dental syringes in this quiz. Learn about the various components, including the syringe parts and different types like aspirating and pressure syringes. Test your knowledge on their uses and mechanisms.