L.A 3

Question 1

Procaine

Answer 1

1- ester
2- Metabolism : plasma pseudocholine esterase
3- the greatest among all L.A
4- pH : plain=5 – 6.5

5- Duration of action :pulpal anesthesia = no
soft tissue anesthesia = 15 – 30 min

Question 2

Procaine uses

Answer 2

1. Immediate management of accidental intraarterial (IA) injection of a drug
2. Aid in breaking arteriospasm

Question 3

Lidocaine

Answer 3

1- amide , lignocaine

2- Metabolism : liver, by microsomal mixed-function oxidase
3- Onset of action :rapid ( 3-5 min)
• Effective dental concentration : 2% (injection)
• Topical anesthetic action : 5% or 10%

4- Plain :pulpal anesthesia = 5 -10 min and soft tissue = 60 -120 min
With epinephrine : pulpal = 60 min and soft tissue =3-5 hrs

Question 4

Lidocaine uses + Comparison of lidocaine with procaine

Answer 4

a) 2% lignocaine– very few dental indication
b) 2% lignocaine with 1: 50000 epi.
– hemostasis
c) 2% lignocaine with 1: 80 000, 1: 100 000, 1:200 000 – local anesthesia

Comparison of lidocaine with procaine
- More rapid onset of action
- More profound anesthesia
- Longer duration of action
- Greater potency
These days lidocaine is “gold standard” of local anesthetics

Question 5

Mepivacaine

Answer 5

1- amide
2 - Vasodilating property: only slight
• Effective dental concentration : 2% with vasoconstrictor,
• 3% without vasoconstrictor.

3- Topical anesthetic action : absent
4-Plain :pulpal anesthesia = 20 to 40 min and soft tissue = 2-3 hr
- With vasoconstrictor (epinephrine or Levonordeferin 1:20 000)
pulpal = 60 to 90 min and soft tissue = 3-5 hrs

4 - Maximum recommended dose :
- Plain 3% mepivacaine : 6.6mg/kg max = 400mg (8 cartridges
of 1.8 ml in 70kg pt.)
- 2% mepivacaine with vaso. : 6.6mg/kg max = 400mg (11 cartridges )

Question 6

Mepivacaine uses

Answer 6

a) 3% mepivacaine plain : pediatric & geriatric pt. –recommended for pt. in whom vasoconstrictor not indicated
& shorter dental procedure.

b) ) 2% mepivacaine Two vasoconstrictor used –levonordeferin (1:20 000) & epinephrine (1:100 000).

Question 7

Prilocaine

Answer 7

1 - amide
2 -Metabolism : liver
3 - causes methemoglobinemia in higher conc.
4 - Vasodilating property: greater than mepivacaine & less than lidocaine
5 - Effective dental concentration : 4%

• Plain : pulpal = 10 to 60 min soft tissue = 2 - 4 hrs
• With epi : pulpal = 60 to 90 min soft tissue = 3 - 8 hrs

Question 8

Prilocaine uses and contraindications

Answer 8

• 4% Prilocaine with 1:200000 epinephrine used in epinephrine sensitive individuals like ASA III cardiac pt.
• Citanest 3% with Octapressin (0.03 IU/ml).
  • Considered to be safest amide local anesthetic

Relative Contraindication:
- Idiopathic or congenital methemoglobinemia
- Hemoglobinopathies ( sickle cell anemia), anaemia
- Cardiac or respiratory failure
- Acetaminophen or phenacetin ( both produce elevations in
methemoglobin.
- Pregnancy.

Question 9

Artricaine

Answer 9

1- amide
2- Metabolism :plasma & liver
3 - Also can cause methemoglobinemia in higher concentration.
4- Vasodilating property : equal to lidocaine
5 - Effective dental concentration : 4% with vasocons

• 4% with 1:200000 epinephrine :
- pulpal = 45 to 60 min and soft tissue = 2 - 5 hrs
• 4% With 1:100000 epinephrine :
• pulpal = 60 to 75 min and soft tissue = 3 - 6 hrs

Question 10

Artricaine
Maximum recommended dose
Contraindications

Answer 10

With vasocons. : 7.0 mg/kg max = 500mg ( 7 cartriges)
• Contraindication :
- Liver disease.
- cardiac & respiratory failure
- Allergy to sulfur- containing drugs ( Articaine is the only
anesthetic of amide type to possess a thiophene ring )

Question 11

Bupivacaine

Answer 11

1- Amide
2- Metabolism : liver, amidases
3 - Excretion : kidney, 16% unchanged is excreted
4 - Onset of action : 6 - 10 min
5 - Effective dental concentration : 0.5% with vasocons.

0.5% with 1:200000 epinephrine :
- Pulpal = 90 to 180 min
- Soft tissue = 4-9 hrs

Question 12

Bupivacaine indications and contraindications

Answer 12

Indications
1. Lengthy dental procedures ( full mouth reconstruction,
implant surgery, periodontal procedures)
2. Management of postoperative pain
Contraindication
1. Younger pt.
2. Physically & mentally disabled children

Question 13

Etidocaine

Answer 13

1- Vasodilating property: greater than lidocaine
2- Effective dental concentration : 1.5% with epi.

The rest same is Bupivacaine

Question 14

Milligrams of local anesthetic per
dental cartridge

Answer 14

Articaine = 72 X 1.8ml =mg/cartridge
Prilocaine = 72
Mepivacane = 54
Mepivacane = 36
Lidocaine = 36
Bupivacane = 9

Question 15

Topical anesthesia is

Answer 15

temporary anesthetic effect , located on the surface of the oral mucosa (2-3 mm).

Question 16

Topical anesthesia Supplied as:

Answer 16

– Ointments ( e.g. lidocaine 5%, benzocain).
– Liquids and gel ( e.g. lidocaine 5%, benzocain 20%).
– Sprays ( e.g. lidocaine 10%).

Question 17

EMLA

Answer 17

(Eutectic Mixture of Local
Anesthetics)

EMLA cream (composed of lidocaine 2.5% and prilocaine 2.5%)

Question 18

Lidocaine topical

Answer 18

aerosol spray 10%, ointment 5% , gel 5%

Question 19

Factors in selection of local anesthetic:

Answer 19

1. Lenght of time that pain control is required.
2. Possibility of discomfort in the postoperative period.
3. Possibility of self-mutilation in the postoperative period.
4. Requirement for hemostasis during treatment.
5. Medical status of the patient.

Question 20

Problem and solution

Answer 20

Bisulphate allergy = LA without vasoconstrictor

Renal dysfunction = amid or esters but judiciously

ASA 3 / 4 = Local anesthetics with epinephrine concentrations of 1:200,000 or 1:100,000 or mepivacaine 3% or prilocaine 4% (nerve blocks)