Local Anesthesia: The Syringe

_______ gauge needles are recommended when using plastic disposable syringes for intraoral local anesthesia.

23 or 25 gauge

What are advantages of the PLASTIC, breech-loading, aspirating syringe?

-eliminated clinical look. -lightweight (provides better "feel" during injection). -cartridge is visible. -aspiration w/ one hand. -rust resistant. -long lasting w/ proper maintenance. -lower cost.

What are disadvantages of the jet injector?

-inadequate for pulpal anesthesia or regional block. -some patients are disturbed by "jolt" of injection. -cost. -may damage periodontal tissues.

What are advantages of disposable syringes?

-disposable, single use. -sterile until opened. -lightweight. -better tactile sensation.

What are advantages of safety syringes?

-disposable, single use. -sterile until opened. -lightweight. -better tactile sensation.

What are disadvantages of disposable syringes?

-does not accept prefilled dental cartridges. -aspiration is difficult because it requires two hands.

What are advantages of the jet injector?

-does not require use of needle (recommended for needle phobics). -delivers very small volumes of local anesthetic (0.01 to 0.2 ml). -used in lieu of topical anesthetics.

What is the criteria set by the ADA for local anesthetic syringes?

-durable & able to withstand repeated sterilization (w/o damage). -capable of accepting wide variety of cartridges & needles (from different manufacturers) while permitting repeated use. -inexpensive, self contained, lightweight, & simple use w/ one hand. -effective aspiration allowing blood to be easily observed in cartridge.

Properly maintained, metal and plastic reusable syringes are designed to provide long-term service. List the recommendations for care of these syringes.

-After each use, the syringe should be washed, rinsed, & autoclaved. -After every 5 autoclavings, the syringe should be dismantled and lightly lubricated (threaded joints & area where piston contacts thumb ring and guide bearing). -Clean harpoon with a brush after each use. -Replace pistons and harpoons as needed (to maintain sharpness).

Use of a safety syringe minimizes the risk of accidental _____________.

needle-stick injury

Where do CCLADs allow local anesthetics to be administered comfortably?

virtually all areas of the oral cavity

When is disengagement of the harpoon most likely to occur?

when a 30-gauge needle is being used; this is because there is a significant resistance produced within the needle lumen as aspiration is attempted

What can cause a broken cartridge?

-a badly worn syringe may damage the cartridge, thus leading to breakage. -a bent harpoon. -positive pressure on thumb ring creating too much pressure within cartridge.

The CCS has a two-stage delivery system. Describe how this works.

-begins at an extremely low rate to prevent pain. -after 10 seconds, automatically increases speed to the preprogrammed injection rate for the technique selected (there are 5 preprogrammed injection rates).

List the 5 types of non-disposable syringes.

-breech loading, metallic, cartridge type, aspirating. -breech loading, plastic, cartridge type, aspirating. -breech loading, metallic, cartridge type, self aspirating. -pressure syringe for PDL injection. -jet injector (needleless).

What are advantages of the METALLIC, breech-loading, SELF-aspirating syringe?

-cartridge visible. -easier to aspirate w/ small hands. -autoclavable. -rust resistant. -long lasting w/ proper maintenance. -piston is scored (indicates volume of local anesthetic administered).

What are disadvantages of safety syringes?

-cost (more expensive than reusable syringe). -may feel awkward to a first time user.

What are disadvantages of the pressure syringe?

-cost. -easy to inject too rapidly. -original devices look threatening.

What types of problems can arise with syringes?

-leakage during injection. -broken cartridge. -bent harpoon. -disengagement of harpoon from plunger during aspiration. -surface deposits.

What are disadvantages of the PLASTIC, breech-loading, aspirating syringe?

-may be too big for small hands. -possibility of infection w/ improper care. -deterioration of plastic w/ repeated autoclaving.

What are advantages of the pressure syringe?

-measured dose. -overcomes tissue resistance. -newer devices look nonthreatening. -cartridges are protected.

What's the difference between negative and positive pressure?

-negative: exerted on the thumb so that blood enters into needle and is visible in cartridge. -positive: applied to thumb ring & forces local anesthetic into needle lumen & patient's tissues.

List the syringe types available in dentistry.

-nondisposable syringes. -disposable syringes. -safety syringes. -computer controlled local anesthetic delivery systems (CCLAD).

What are advantages of the Wand/CompuDent System?

-precise control of flow rate & pressure produces a more comfortable injection (even in tissues with low elasticity). -increased tactile feel and ergonomics (due to lightweight handpiece). -looks nonthreatening. -automatic aspiration. -rotational insertion technique minimizes needle deflection.

What are disadvantages of the Wand/CompuDent System?

-requires additional armamentarium. -cost.

Describe the two rates of delivery with the Wand.

-slow: 0.5 ml/min. -fast: 1.8 ml/min.

What is the PDL injection used for?

-usable for any tooth. -helps achieve consistently reliable pulpal anesthesia of one isolated tooth in mandibular arch.

What are advantages of the METALLIC, breech-loading, aspirating syringe?

-visible cartridge. -aspiration w/ one hand. -autoclavable. -rust resistant. -long lasting w/ proper maintenance.

What are disadvantages of the METALLIC, breech-loading, aspirating syringe?

-weight (heavier than plastic). -may be too big for small hands. -possibility of infection w/ improper care.

What are disadvantages of the METALLIC, breech-loading, SELF-aspirating syringe?

-weight. -feeling of "insecurity" for those accustomed to harpoon style syringes. -finger must be moved from thumb ring to thumbdisk to aspirate. -possibility of infection w/ improper care.

The SyriJet holds any 1.8 mL dental cartridge, but is calibrated to deliver ____ to ____ mL of solution at 2000 psi.

0.05 to 0.2 mL

The incidence of positive aspiration may be as high as ______ percent in some injection techniques.

10 to 15 percent

The self-aspirating syringe was introduced in what year?

1981

Label!

A: needle adaptor B: harpoon C: finger grip D: thumb ring E: syringe barrel

Who patented the first syringe and when?

Charles Pravaz; 1853

______ is the greatest disadvantage to use of the pressure syringe.

Cost

True or False? The jet injector is an adequate substitute for the traditional needle and syringe in obtaining pulpal or regional block anesthesia.

False! It is NOT an adequate substitute. Many patients dislike the feeling and there is a possibility of postinjection soreness of soft tissue.

True or False? An aspiration test is optional and not necessary.

False! It is of great importance to perform an aspiration test before/during administration of a local anesthetic.

True or False? Safety syringes are designed to be used multiple times.

False! They are single-use only.

True or False? Plastic disposable syringes still contain an aspirating tip.

False! They have a Luer-Lok screw-on needle attachment, but no aspirating tip.

Do plastic disposable syringes accept dental cartridges?

No. They must be inserted into a vial or cartridge of local anesthetic drug and an appropriate amount of solution withdrawn.

Should pressure syringes be injected rapid or slow?

Slowly! If administered too quickly the patient may feel discomfort.

The most used jet injectors in dentistry are the __________ and _________.

SyriJet and MadaJet

What is another type of CCLAD available in North America besides the Wand?

The Comfort Control Syringe (CCS) which attempts to approve on the CCLAD concept

Why do plastic disposable syringes require both hands to aspirate?

There is no thumb ring.

____________ applied properly serve the same purpose as jet injectors at a fraction of the cost.

Topical anesthetics

True or False? The plastic breech loading syringe is autoclavable.

True! It can be autoclaved or chemically sterilized.

True or False? Use of the plastic disposable syringe is not recommended for routine use.

True! It should only be considered when a traditional syringe is not available.

True or False? Ultrasonic cleaning will not harm syringes.

True!

True or False? There is a reduced pain perception noted by most patients with use of the Wand.

True! The precise rate of flow and controlled pressure influence this.

Can standard dental local anesthetic cartridges and needles be used in the CCS?

Yes!

Does the self-aspirating syringe aspirate as reliably as the harpoon-aspirating syringe?

Yes! But most doctors using the harpoon-aspirating syringe tend to overaspirate

Basic syringe definition.

a drug delivery device requiring that the operator simultaneously attempt to control the variables of drug infusion and movement of a penetrating needle

How is local anesthetic delivered with the Wand?

a foot activated control that allows anesthetic to be delivered at a pre-programmed rate of flow

What allows safety syringes to prevent accidental needle sticks?

a sheath that locks over the needle

Describe the CCS.

an electronic, preprogrammed delivery device that provides the operator w/ the control needed to make patients local anesthetic injection experience as pleasant as possible

What can cause leakage during injection?

an off-center perforation produces an ovoid puncture of the diaphragm that allows leakage of anesthetic solution around the outside of the needle and into patient's mouth

Describe jet injection.

based on the principle that liquids forced through very small openings (called jets) at very high pressure can penetrate intact skin or mucous membrane

____________ is the most commonly used syringe in dentistry.

breech-loading, metallic, cartridge-type, aspirating

Define syringe.

the vehicle whereby contents of the anesthetic cartridge are delivered through the needle to the patient

Define breech-loading.

cartridge inserted into syringe from side

What type of anesthetic delivery system is the Wand System?

computer-controlled local anesthetic delivery system (CCLAD)

What type of surface deposits can accumulate and interfere with syringe function/appearance?

debris, saliva, and disinfectant solution

The Wand was designed to improve ___________ and ____________.

ergonomics and precision

What is the major factor influencing the ability to aspirate?

gauge of the needle being used

The aspirating syringe has a device called the ____________ that is attached to the piston and is used to penetrate the thick silicone rubber stopper at the opposite end of the cartridge.

harpoon

What are plastic disposable syringes most often used for?

intramuscular or intravenous drug administration; may also be used for intraoral injections

How many uses may be obtained from the plastic breech loading syringe?

multiple uses as long as proper care and handling are applied

Rotation of the handpiece and needle of the Wand minimizes __________ and _____________.

needle deflection and force necessary for tissue penetration

Pressure syringes brought a renewed interest in the ______ injection.

periodontal ligament injection (AKA intraligamentary injection)

What issues arise from a bent harpoon?

produces an off center puncture of rubber plunger, causing the plunger to rotate as it moves down the cartridge which occasionally results in a broken cartridge; harpoons MUST be sharp & straight.

List the three essential components of the local anesthetic armamentarium.

syringe, needle, and cartridge

Describe how self-aspirating syringes work.

these syringes use the elasticity of the rubber diaphragm in the anesthetic cartridge to obtain necessary negative pressure for aspiration

What is the primary use of the jet injector?

to obtain topical anesthesia before insertion of a needle; it may also be used to obtain mucosal anesthesia of the palate

When using a CCLAD system, overall pain perception is reduced ________ when compared with standard manual syringes.

twofold to threefold