This lecture discuss very important topic in dental practice and that is the science and art of dental anesthesia. This lecture discuss various techniques, precautions, and tips about dental anesthesia for restoration and endodontics.

1. Factors Affecting Endodontic Anesthesia
Factors Related To Injection Pain
When To Anesthetize?
Anesthetic Precautions
Anesthesia For Restorative Dentistry
Anesthesia For Endodontics
FACTORS AFFECTING ENDODONTIC
ANESTHESIA
These factors can affect successful delivery of anesthe-
sia:
• Anxiety: many patients have heard horror and ter-
rifying stories about endodontic treatment. How-
ever, according to a survey, 96% of patient would
agree to have future root canal treatment. This
mean these terrifying stories are unreasonable.
• Fatigue: endodontic patient who come to the clinic
had not slept well in the past days, and not eaten
well. This result in patient with decreased ability to
manage stress and less tolerance for pain.
• Tissue inflammation: inflamed tissue have lower
pain threshold and easily get irritated.
• Previous unsuccessful anesthesia: some patients
have past history of unsuccessful or difficult anes-
thesia. Dentist should recognize these type of pa-
tient and deal with their condition accordingly.
FACTORS RELATED TO INJECTION PAIN
• Topical anesthesia: some authors agree with it
while others find little evidence for its efficacy.
However, its use is recommended and may help
lower patient pain and anxiety.
• Warming anesthetic solution: this matter is not
settled yet and require further studies. Some au-
thors agree with its efficiency while others dis-
agree.
• Small-gauge needles (small diameter): a com-
mon misconception is that smaller diameter nee-
dles cause less pain to the patient, However, there
is no difference. 27 gauge needle is recommended
for most dental procedures including endodontics.
• Slow injection: slower injection result in less pain
and discomfort.
• Two-stage injection: it consist of initial slow ad-
ministration of 1/4 of cartridge just under mucosal
surface, after mucosa has been anesthetized, nee-
dle is inserted to the full depth of the target and
anesthetic solution is administred. This technique
result in less pain for the patient.
• Gender differences: women are more fearful and
they may present a challenge sometimes.
WHEN TO ANESTHETIZE ?
Anesthesia should be given at each appointment. There
is a common believe that necrotic teeth require no an-
esthesia during preparing and cleaning phase of root
canal treatment. However, this is untrue. Occasional-
ly there may still some vital tissue and nerve fibers in
the apical few millimeters in the canal and may cause
patient discomfort if not anesthetized. Also sometimes
periapical ingrowth of tissue into the canal has oc-
curred and will result in patient discomfort if not anes-
thetized properly.
Another misconception is that tooth require no anes-
thesia during obturation phase. However, this is also
untrue. During obturation pressure is created and small
amount of sealer may extrude out of the apex and re-
sult in patient’s pain.
ANESTHETIC PRECAUTIONS
Anesthesia with vasoconstrictor should be avoided
in patients with high blood pressure (> 200 mmHg),
cardiac dysrhythmias, sever cardiovasuclar disease,
Anesthesia for restorative and
endodontic procedures
Osama Asadi, B.D.S, Published for Iraqi Dental Academy Blog
Obtaining adequate anesthesia in patient with endodontic lesions can sometimes be challenging. A good
technique and understanding of science and art of anesthesia is essential.
LECTURE OUTLINE
CHAPTER
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2. unstable angina, or who are less than 6 months past
a myocardial infarction or cerebrovascular accident.
These conditions are contraindicated for routine dental
procedure.
Patients taking antidepressants, nonselective be-
ta-blockers, medicine for Parkinson disease, and co-
caine should not be given anesthesia with vasoconstric-
tor. These patients are given plain anesthesia such as
plain mepivacaine.
ANESTHESIA FOR RESTORATIVE
DENTISTRY
Mandibular Anesthesia for Restorative
Dentistry
Anesthetic technique of choice is inferior alveolar
nerve block(IANB). Local infiltration is not effective
because of density of mandibular bone. Alternative
techniques for the mandible include Gow-Gates, and
Vizarani-Akinosi techniques, however, they are not
Superior to IANB technique.
Inferior Alveolar Nerve Block
Onset of pulpal anesthesia with this technique is 5-9
minutes for posterior teeth, and 14-19 minutes for
anterior teeth.
Duration of pulpal anesthesia is very good. Anesthesia
can last usually (but not always) to 2 hour and a half.
Incidence of successful IANB is higher in posterior
teeth and lower in anteriors. Sometimes a good anes-
thetic technique is applied but anesthetic fail, this is
related to several factors.
Factors Affecting Failure of IANB
• Accuracy of needle placement: sometimes failure
occur, even with accurate insertion of needle with
ultrasound. Accurate insertion is not a guarantee
for successful anesthesia and other supplemental
techniques should be considered.
• Needle deflection: some authors theorized that the
needle deflect or bent in the journey to target site
and that result in inaccurate anesthetic delivery.
However, studies have shown that this does not
affect success of IANB.
• Acessory innervation: anatomic evidence has
shown that there may be sometimes accessory
innervation from mylohyoid nerve. However, in
studies they blocked mylohyoid and inferior alve-
olar nerve and there was no enhancement of pulpal
anesthesia. So it is not a major factor in failure.
• Cross-innervation: anterior teeth may have in-
nervation from both right and left inferior alveolar
nerves. However, it is not a major cause for
failure.
How increase success of IANB
• Studies have shown that local infiltration with
articaine after IANB result in pulpal anesthesia
for 1 hour.
• Intra-osseous injection after IANB
• Intraligamentary injection after IANB.
• Injection speed: slow injection increase success of
IANB.
Maxillary Anesthesia for Restorative
Dentistry
Local infiltration is the anesthetic technique of choice
for maxillary teeth.
Onset of pulpal anesthesia with this technique is 3-5
minutes. However, duration of pulpal anesthesia is an
issue here. For anterior teeth it can last for 30 min-
utes, and posterior teeth for 45 minutes. This require
additional anesthesia after that period.
Other techniques exists such as posterior superior
alveolar block, infra-orbital block, and second divi-
sion block. However, these techniques are not used in
routine restorative dental procedures.
Supplemental Anesthesia for
Restorative Dentistry
When routine anesthesia fail to acquire a state of pul-
pal anesthesia, additional techniques are required to
obtain pulp numbness. These technique are:
• Infiltration injection
• Intra-osseous injection
• Intraligamentary injection
Intra-osseous and intraligamentary techniques should
not be used in necrotic teeth with periapical radiolu-
cency or teeth with cellulites or abscess.
The exact procedure of these technique are left to you
to discover in Handbook of Local Anesthesia Text-
book by Stanley Malamed.
ANESTHESIA FOR ENDODONTICS
Primary anesthetic technique for maxillary teeth is
infiltration and for posterior teeth is IANB. When
that fails, additional intraosseous or intraligamentary
injection is made to anesthetize the pulp.
A good practice is to anesthetize the tooth, then after
lip and soft tissue numbness has occurred, tooth is
tested with electrical pulp test or cold test, and if no
pain present, tooth can be opened and prepared easily.
And if pain is present additional anesthetic technique
is required.
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3. Anesthesia of tooth with pulpal or
periapical pathosis
• Irreversible pulpitis: primary anesthesia is
applied. When failed, additional intraosseous or
intraligamentry anesthesia is applied.
• Symptomatic pulp necrosis: primary anesthesia
is applied. If that fails, intraosseous and intra-
ligamentary are contraindicated in such teeth. In
maxilla, other techniques such as Posterior supe-
rior alveolar block or infraorbital block may be
helpful. Patient should be informed that profound
anesthesia is not present due to inflammation in
the bone.
• Asymptomatic pulp necrosis: these teeth are eas-
iest to anesthesia. However, some practitioner does
not anesthetize such teeth and this is unacceptable.
REFERENCE
Endodontics Principles and Practice, 5th Edition.
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