4) Local Anesthesia( Dr Arwa )

8/13/2019 4) Local Anesthesia( Dr Arwa )

1/21


2/21

Pediatric Dentistry Local Anesthesia

Given by Dr. Arwa

Date: 13/02/2013

***The pediatric practical exam will be on the same day of the midterm of the preventive. Most probably on

April 3rd

.

the exam will include writing History, diagnosis & treatment plan.

Analgesia:The elimination of pain in the conscious patient.

Local anesthesia: Is the loss of sensation in a circumscribed area of the body (localized

area).

Many studies have been conducted regarding local anesthesia. In Canada dentistsinject around 1800 cartridges of LA yearly, but in Jordan there are no available

figures.

And more than 300 million cartridges are administered by dentists in USA.

Injecting LA may not only provoke anxiety in patients, but also in dentists. In a study in California, It was found that giving LA is the most stressful procedure

for the dentist.

And some dentist reconsidered dentistry as a career because of local anesthesia.

So if that was the feeling of the dentist, imagine the feeling of the child.

Local Anesthesia for Pediatric Dental Patient


3/21

It depends on the polarization & repolarization of the membranes of the nerves.

So it penetrates the nerve cell membrane and block receptor sites that control the influx ofsodium ions associated with membrane depolarization.

Therell be loss of sensation in the tissue.

This is a mistaken notion in the clinic, so make sure not to repeat it:

Once a critical concentration of local anesthetic reaches the nerve, impulse conduction

through that nerve is blocked in all-or-none fashion.

So, if the patient feels numbness in the lip, that means hes anesthetized for sure.

If the patient feels numbness in both (the lip & the tongue) to the level of midline, this is an

indication for an effective full anesthesia.

Or if the explorer can be run through the buccal and lingual gingiva without pain, this

means the patient is probably imagining that the tooth is painful.

Sometimes, the child tells you that he feels no pain, but when you start extracting thetooth, he starts feeling pain, and thats because the level of anesthesia is different.

Anatomy of the nerves:

This is an axon bundle, and these are

axons,

and blood vessels.

Mechanism of action:


4/21

The all-or-none fashion:Each nerve bundle has many axons, and depending on the number of axons

anesthetized, the level of anesthesia will vary.

SO each axon is either anesthetized or not.

But the number of axons anesthetized determines the level of anesthesia for thenerve.

Againits NOT all-or-none for the whole nerve; its for each axon in the bundle.

The bundles are supplied by intraneural vascular system. For the conduction of nerve impulses to be blocked, an adequate concentration of

LA must diffuse through all of these tissues before reaching the axonal membrane.

The most important factor in this process is having a sufficient concentration of LAdeposited close to the neuronal membrane, enabling diffusion to the nerve.

When a child feels pain during a clinical procedure despite all signs of a successfulblock, it is often due to an insufficient number of axons within the nerve being

blocked.

This problem could be overcome by allowing enough time to elapse for anesthesiato take place. Or increasing the concentration of LA given to the nerve.

There is no perfect technique that guarantees success in anesthetizing all children.However, there are a few key procedures that are mutual to all administrations that

may be valuable to the success of all techniques.

The first technique is TOPICAL ANESTHESIA:

There are many flavors, and all are used to decrease the amount of discomfort forthe needle penetration.

Its topical to the mucosal membrane,so itll not anesthetize the tooth. A child is given the choice of choosing the flavor. Most of them like strawberry.

But never give an option wouldyou like this gel or the needle?


5/21

Must be placed on the dried mucosa. And you dry it using gauze, not 3 in 1. Because3 in 1 is painful and irritating for children.

The gel must be placed for at least 1 minute to achieve maximum effect. The most common type used is Benzocaine (20%), and Lidocaine (5%), or EMLA

cream (but we dont use it in our clinics).

There are 3 different lengths of needles:Long, short, or ultra-short.

Long needle is FORBIDDEN is the pediatric dentistry clinic. We dont use it at all. Sofor ID block use the short needle.

And for infiltration we use the ultra-short. The short needle (20 mm) may be used for almost all intra-oral injections in

children. But the long can be used in very obese children.

The ultra-short needle (10 mm) 30-gauge is used for maxillary anterior injections,or even upper posterior teeth.

Clinical experiences have shown that shorter needles are adequate and safeespecially for the young, uncooperative children.

Needle Size and Length:


6/21

Q: Whats the difference between 27 gauges and 30 gauges? Its the diameter of the tip of the needle.

The larger the gauge the finer the needle.

Thats why we use 30 gauge/10 mm needles. Now, as you can see the needle has a bevel. This bevel should be placed opposite to

the bone. So that the solution reaches directly to the bone area. And you wont get

the complication of having a bullous.

You cant show the needle to the child, and you need to give it quickly, so how canyou see where the bevel is?

If you look at the cup, or the plastic part of the needle (while its still covered),

you will see a black arrow, its an indicator of the side of the bevel, so that you canplace it right.

Once a child has grabbed the syringe or bumped the operators hand and driven theneedle into the tissue or the bone, it may be too late to respond, and a lasting

impression has been made in the childs mind relative to the pain associated with LA

injection.

Some authors recommend that the practitioner should have a control of the childshead, and a good finger rest, to control the syringe in case the child moves or resists.

Controlling Childs head:


7/21

The dental assistant should be prepared to restrain childshands. And not restrainhis hands from the beginning, because he will expect that something painful or bad

is going to happen.

If you use topical anesthesia, and block the childs view, and give it slowly,everything will be fine and wont have to restrain his hands, but the head should be

controlled.

There are many formulations of LA. And depending on the type of anesthesia I wontachieve, Ill decide what type to use and whether to use it with or without

epinephrine.

Check the table in the slides. The doctor said that you need to memorize thenumbers. Because you need to know how much time you have.

Ex. If you are going to do pulpotomy, and you give LA at 9 am, and started workingvery slow, you should expect that therell be no pulp anesthesia by 10 am. So you

need to supplement LA again before proceeding into pulpotomy.

Because 60 minutes is the maximum time of perfect anesthetic solution that I

deposited in a child for pulp treatment.

Go back to the slides on page # 7. You can note from the table that in ID block thattime is more.

And the most common type of anesthetics used pediatric dentistry is Lidocaine with

1:100,000 epinephrine.

Also the table on page # 7 shows the maximum doses of LA. And its very importantto know the maximum dose given to the child. Depending on his weight.

So Lidocaine 2% max. dose is 4.4 mg/kg. Prilocaine max. dose is 6 mg/kg.

This semester youll practice how to calculate the maximum dose of LA. Go to theslides on page # 8 for illustration of the calculations.

Duration of action:


8/21

In general. Without doing calculations.For every 10 kg, you are allowed to use 1 carpole (lidocaine 2%) for the day (not for

the session).

Suppose a child who is 20 Kg, you are allowed to use up to 2 carpoles for the day.

So if the child has been treated in the morning. And you invited him for an extractionin the afternoon; make sure you know how much anesthesia he has been giving in

the morning.

1.Amides: Detoxified in the lever. Examples: Carbocaine/ Lidocaine.

2. Esters: Metabolized by plasma enzyme cholinesterase. Example: Procaine.

Note:All LA readily cross the blood-brain barrier and the placenta and enter the fetal

circular system.

Q: Why do we use vasoconstrictors?

-To improve the quality of pain control.

-Does vasoconstriction and make it localized, so decreases the amount of LA needed to

anesthetize a certain area.

-decrease the potential toxicity of the LA.

Vasoconstrictors can be: Epinephrine or non-epinephrine.

Local Anesthetic Agent:

Vasoconstrictors:


9/21

Q: When do we re-inject LA?

Its preferable to re-inject LA, while its still working.Example. You were going to do pulpotomy, and you know LA works for 60

minutes. And for some reason (the child was uncooperativeetc) so you lost

some time without doing anything, so the best time to re-inject, is before starting

pulpotomy, this will give a profound effect. Do not wait until the child feels pain,

or LA is worn off.

Recurrence of immediate profound Anesthesia:If LA has not worn off, the combination of residual anesthetic with the new supplyresults in rapid onset of profound anesthesia.

Its increasing tolerance to a drug that is given repeatedly. More likely to develop if nerve

function is allowed to return prior to reinjection.

Example: The patient feels pain, so you give LA, then he feels pain again, and you give LA

again. So if you are doing extraction or pulpotomy, give a proper amount from the

beginning.

As we said earlier, theres no perfect technique.Needle size:

The larger the gaug the smaller the needle. We use only 27 or 30. Use only short or ultra-short. The long is for adults or obese adolescence.

Re-injection of Local Anesthesia:

Tachyphylaxis:

Techniques for administering LA:


10/21

Aspirating The syringe:

The syringes that we have in the clinic are self-aspirating syringes. Always, when you insert the needle, look at the carpole, to make sure you are not in

the blood stream.

Topical Anesthesia:

We talked about it at the beginning of the lecture.

Remember: always use it.

You have to hide the syringe. By passing it behind or over the patient. Block patients view with your retracting hand. Be confident. Use Euphemisms:

Its using words that you say in childrens way like:

I am going to put tooth jelly, or we are going to place sleepy juice besides your tooth,

or we are going to use bubble blower.

Also some books use mosquito bite, but the doctor doesnt recommend that, because

a bite is painful, and the child will relate it to pain, we dont want to give any

indication for the child that the procedure is going to be painful.

Syringe management and etiquette:


11/21

You also can say, the tooth is going to take a nap and feel fat &fuzzy. Use your own

words, but do not use anything related to pain.

Distraction:

Its very important; you may talk to the child about anything he/she likes. Pull the check. Why? Because its makes the penetration less painful, and gives us clear view.

Touch the face?Because itll distract the child, because therell a pressure feeling on his face.

Keep things moving.

- Take a look at the skull on page # 16.

- There are primary and permanent teeth:

So when injecting, always imagine where the apex of the root is.

So for example, if I want to extract a tooth that has resorbed roots, I look at the

radio graph, and inject in the area of tooth apex.

Do not go very deep when injecting for children, so you dont injure the follicle of

permanent teeth.

Some Anatomic differences in the mandible:

Ramus is shorter vertically and narrower anteroposteriorly. The mandibular foramen is lower than in adults (may be even below the occlusal

plane).

You have to know the nerve supply for both maxilla and mandible (soft & hardtissue).

Anatomic Differences:


12/21


13/21

Bilateral inferior alveolar blocks should not be administered to children. Why?Because it increases the chances of post anesthesia trauma. The child will bite his

cheek and tongue. And thats inconvenient.

For extractions:Anterior teeth: infiltration

Posterior: although block may be best for extractions, but we look at the root

length, if the roots are resorbed and the tooth is mobile, we just anesthetize the soft

tissue ( we give LA buccally and lingually around the tooth)

The Maxilla:

Maxillary infiltration:

You have to know the nerve supply for each area. Apices of primary anterior teeth are at the depth mucobuccal fold. (So use either the

short needle, or ultra-short the dr prefers the ultra-short).

How to do it:

1. Stretching the mucosa of the injection site is recommended for buccalinfiltrations.

2. The needle should penetrate the mucobuccal fold and be inserted to the depth ofthe apices of the buccal roots of the teeth.

3. After a few seconds the needle can be slowly advanced 1-2 mm and after anegative aspiration =, another small amount of solution can be deposited.

4. The solution is deposited supraperiostally and infiltrates through the alveolarbone.

Always inject suraperiostally , and never sub-periostally, because its verypainful.

Infiltration is used for anesthetizing primary molars and premolars.


14/21

Primary second molars may have innervation from posterior superioralveolar nerve, so inject behind the tuberosity.

For permanent molars, inject behind the tuberosity. Sometimes we do interdental papillary injection to achieve palatal anesthesia.

Its used in children, because giving incisive block/infiltration in the palate is

really painful.

So if you want to do extraction for a child for an upper anterior, give:

1. Buccal infiltration.

2. Interdental papillary infiltration. (Youllsee blanching in the palatal area).

Again, we give indirect palatal injection, by injecting the interdental papillaryarea (buccally), and therell be blanching in the palatal area, which means its

successful.

Interdental papillary anesthesia is not very successful in adults as in children.

PDL Injection:

Used in additional or supplemental anesthesia. Usually done when working on both sides of the mandible, to avoid giving

bilateral ID block.

Intraligamentary Anesthesia:

Sometimes when there are extra nerves, or supplemental nerves in the area, and theconventional method fails, we use this method.

1. The needle is inserted in the mesio-buccal aspect of the root and advanced untilmaximum penetration.

2. The needle does not penetrate deeply into the periodontal ligament but is wedged atthe crest of the alveolar ridge.

There are many devices used for giving intraligamentary anesthesia.


15/21

DO / DONT:

Do:

- Always be confident, if you dont know how to do it, then dont do it ,because thechild will be traumatized.

- Keep talking to distract the child.- Maintain hand and head control.- Have assistant (or your partner) stay alert.- Shield and distract vision of the recipient and neighbors.

Dont:

- Dont openly display the syringe.- Never use words like Shot, needle, or hurt.- Dont inject too fast (its very painful). Inject slowly. - Dont tell him to close his eyes ( blockthe view with your hand), because when

you tell him that, hell know that theres something you dont want him to see.


16/21


17/21

Complications can be Generalized or Localized. Localized complications are either early or late.

1. Psychogenic.2. Allergic.3. Toxic effects.4. Methemoglobinemia.5. Drug interactions.6. Infection.

- The most common in children. Especially with dentists who are not confidentenough to give slow, good quality anesthesia.

- Youll see signs like:1. Syncope.

2. Hyperventilation.

3. Nausea and vomiting.

4. Alterations in heart rate or blood pressure.5. And sometimes youll notice signs of allergic reaction like: edema, urticarial

and bronchospasm.

-

- Includes allergies from esters, epinephrine, and others. Also latex allergy.- Allergy from local anesthesia is very rare.- If the patient tells you that he has LA allergy, you have to refer him to a physician

or allergist.

Generalized Complications:

Psychogenic (anxiety-induced)

Allergic (potential allergens)


18/21

- When you give LA more than the allowed dose, therell be a toxic effect.- Signs of toxic effect:

* May initially manifest as sedation, lightheadedness, slurred speech, mood

alteration, diplopia, sensory disturbances, disorientation, muscle twitching.

** Higher blood levels may result in tremors, respiratory depression, tonic-clonic

seizures.

*** If severe, may result in respiratory arrest.

- Its very rare to happen if you follow the maximum allowed dose. Prevention of toxicity:

1. Aspiration: because when LA reaches to the blood, itll cause systemic toxicity.

2. Slow injection.

3. Dose limitation.

Treatment of toxicity:

1. Stop dental treatment.2. Call for medical assistance.3. Protect patient from injury.4. Monitor vital signs.5. Provide basic life support.

- Its a systemic toxicity, may occur because of Prilocaine.- Decreases the amount of type of hemoglobin, and might be life threatening.- So the dose limit of prelocaine should be strictly obsereved.

Toxic effects

Methemoglobinemia


19/21

- If the child is on any long-term therapy, you have to consult the physician, tomake sure there wont be any interaction with LA.

- Cross-infection measures should be applied.

***Happen in the clinic, or in the same day of the procedure.

1. Pain because improper technique.2. I.V injection When you dont pay attention to aspiration.3. Failure of LA because of: 1. Anatomic differences.

2. Not given properly.

4. Motor nerve paralysis- related to parotid gland position.5. Interferences with special senses.6. Hematoma formation when injuring blood vessels.7. Blanching because of epinephrine.

- Sometimes warming LA cartridge just before administering LA will causediscomfort, because LA should be placed in the fridge.

- When a local anesthesia fails, generally, it is best to repeat the injection; this willoften lead to success. In the case of repeated block injections it is easier to

palpate bony landmarks at the second attempt as the needle can be maneuvered

in the tissue painlessly.

Drug Interaction

Infection

Localized Complications:

Early Complications:


20/21

- In case of prolonged impairment sensation, the cause is usually related to inta-arterial injection. And in this case the patient has to be monitored, and called

back for review.

- Hematoma formation: sometimes when giving a nerve block, you might injure ablood vessel. So hematoma will form.

Treatment: give antibiotics, because there is a possibility that the hematoma will

get infected.

And the patient should be review after two weeks.

- Blanching: itll go away by itself.

*** Happens after leaving the clinic.

1. Trauma because of biting.2. Oral Ulceration its either minor or major.3. Long-lasting anesthesia.4. Trismus but its very rare.5. Infection.6.

Developmental defects.

Q: How to prevent trauma?

- By warning parents and giving instructions.

- If the patient was injured (Ex. lower lip bite), the wound should be kept moist.

- Trauma (lip biting) is the most common post-operative complication.

- Sometimes placing a cotton roll between the teeth will help remind the patient not to

chew.

*Oral Ulceration: could be minor or major. Or herpes simplex but it is rare.

*Parasthesia: loss of sensation because of nerve injury.

Late Complications:


21/21

*Trismus: Sometimes when giving LA, tearing of muscle fibers can happen, but it usually

resolves spontaneously.

*Infection: Happens due to introduction of bacteria into the injection site.

*Developmental defects: due to injury of the developing follicle.

Done By: Katreen Suleiman

Documents

4) Local Anesthesia( Dr Arwa )