Conse iv script-5-management-of-local-anesthesia-in-endodontics

2. Cons IV
31/10/2012 wed
‫الرحمي‬ ‫الرمحن‬ ‫هللا‬ ‫بسم‬
Management of local anesthesia in endodontics
Our lecture today is about the management of local anesthesia in endodontics ,we took the
conventional techniques (ID – block & infiltration ) last year so we are not going to talk
about their techniques, we will talk about factors affecting them and supplemental
techniques …
Factors affecting endodontic anesthesia
1-apprehension, anxiety & fatigue:
Usually the pt came for us with pain,he did not sleep for many days , he did not eat
so he came anxious ,also he came with fatigue so he can't tolerate pain , he can't
tolerate stress ,you have to manage the pt ,you have to do psychologically
reassurance for him/her before giving the anesthesia .
2-tissue inflammation (hyperalgesia):
Also we have symptoms ; inflammation (pulpitis) so the anesthesia is more difficult
when we have symptoms ,,for ex. If we have conventional anesthesia for class I
with pulpitis ,,it will be more difficult .
3- previous unsuccessful anesthesia:
Sometimes pt come to us , he said I've been given 2 needle & the conventional
anesthesia does not work ,in this case supplemental anesthesia is better especially in
root canal treatment .
Now conventional anesthesia as we mentioned is two types :

3. --Maxillary anesthesia --mandibuar anesthesia
And supplemental anesthesia involve three techniques :
1-periodontal ligament anes. (intraligamentary)
2-intraosseous anes.
3-intrapulpal anes.
The success of local anesthesia vary according to the arch,for ex. Maxillary
anesthesia (infiltration) usually more successful than ID block in the lower teeth .
And also depend on the operation we want to do { restorative tx is easier than
endodontic,,also endodontic more difficult than extraction according to two things:
-operation we want to do (if pulp extirpation or RCT).
-anxiety level;anxious pt will have lower threshold of
pain perception [feel pain rapidly ,difficult to treat]
Mandibular anesthesia :
Usually we use anesthetic agent as 2% lidocaine with 1 : 100,000 epinephrine .
Now the related factors to mand. Anesthesia :
1-lip numbness :
It takes usually (5-7)minutes when ID block is given
2-onset of pulpal anesthesia :
But lip numbness does not mean that the pulpal anesthesia occurs ,it takes longer
time for the pulp to anesthetize about [10-15] minutes .

4. 3-duration of pulpal anesthesia :
Duration 2 & 1/2 hr which is excellent ,, u have long time to work .
4-Success rate of ID block :
More successful in molar and premolar than in anterior teeth .
5-alternative techniques to mandibular anesthesia :
is to increase the success of ID block not the supplemental technique .
6-increasing the volume :
Sometimes we give two injections instead of one ,but if the pt have lip numbness
,cheek numbness ,increasing the volume does not increase the success of the pulpal
anesthesia not like the infiltration .
So if the pt have cheek numbness ,lip numbness or tongue numbness we have to
try supplemental techniques .
[[that mean if anesthesia does not work (failed)& the pt numb we can't use the
same tech. again we try another one ]]
7-alternative injection location :
Gow-gates tech. instead of standard (conventional)ID block ,the basing tech. is not
superior in pulpal anesthesia than ID block ,it's useful in Trismus cases but not
superior to the ID block .
so the first one we give ID block ,but if pt have trismus we give other techniques .

5. 8-infiltration injection :
Not useful at all to give buccal or lingual infiltration anesthesia in lower teeth due
to the thickness of bone .
9- long -- acting anesthesia :
Ropivacaine (not sure) instead of lidocaine will give "4" hrs anesthesia ,but two
and half hrs is enough .
Analgesics can be given after finishing the Tx instead of "4" hrs anesthesia .
Long-acting anesthesia only to increase the duration of pulpal anesthesia .
.is the inability to normally open the mouth due to one of many causesTrismus
Injection technique
There are a number of techniques that are commonly used to achieve inferior alveolar nerve
anaesthesia. The most commonly used techniques involve an attempted block of an entire
portion of the inferior alveolar nerve:
Standard mandibular nerve block - The nerve is approached from the opposite side of the mouth
by angling the syringe from the premolars on the opposite side. After piercing the mucosa and
the buccinator muscle between the palatoglossal & palatopharangeal folds until hitting bone (the
ascending ramus), the syringe is drawn backwards slightly and brought parallel to the width of
the ramus, so that the needle lies lateral to the medial pterygoid at the mandibular foramen.
Gow-Gates technique - Invented by Australian dentist George A.E. Gow-Gates in the mid-1970s,
the needle is directed at the neck of the condyle just under the insertion of the lateral pterygoid
muscle.[2
Wiki
Bupivacaine has a somewhat slower onset than 2% lidocaine but almost twice the duration of
pulpal anesthesia (approximately 4 hours) in the mandible .
Ropivacaine is a structural homologue of bupivacaine that appears to have a lower potential for
central. wiki

6. 10-accessory innervation :
Usually from the mylohyoid branch , if we give mylohyoid anesthesia it doesn't contribute
largely to the sensitivity of pulpal sensation so  no need .
In the figure above :
C inferior alveolar nerve
D mylohyoid branch of Inferior Alveolar nerve
11-cross innervation :
cross innervation from the contralateral inferior alveolar nerve has been implicated
in failure to achieve anesthesia in anterior teeth after an inferior alveolar injection.
Experimentally, cross innervation occurs in incisors but plays a very small role in
failure with the inferior alveolar nerve block , and has minor contribution to the
sensitivity of the pulp.
12-pain & inflammation :

7. Inflamed tissue has lower perception threshold to the stimulus so alternative
technique of ID-block usually doesn't work .
Maxillary anesthesia :
Now we will talk about max. anesthetic related factors:
 lip numbness:
In max. anesthesia lip numbness is very rapid .
success & rate :
Infiltration has higher success rate than ID-block .
onset of pulpal anesthesia :
Also it's rapid ,it takes 3-5 min ,while the ID take 10-15 min [sometimes we give
the ID & think it doesn't work ,,NO we have to wait 10 to 15 min then try another
technique if it failed] .
 duration of pulpal anesthesia :
The duration 30-60 min ,it's too short so we may give another injection .
 the alternative tech. as we said to improve the maxillary infiltration .
 Volume of solution : here it differs ,when we increase the volume (2 or more
cartridge will increase the pulpal anesthesia not like the ID block ).
Alternative solution : like the ID no need to change the anesthetic agent
{lidocaine is affective }
 other techniques : if we are treating more than one tooth we can use
infraorbital block or superior alveolar nerve block ,but if we treat one tooth
,infiltration is enough .

8.  pain & inflammation :same as ID-block
Supplemental anesthesia
Now we will talk about supplemental anesthesia ….
Indications :
; DO NOT START WITH SUPPLEMENTALtechnique not workif standard-1
TECHNIQUE , START WITH CONVENTONAL ONE .
Then if it failed try the supplemental .
it's not useful to repeat conventional anesthesia :-2
For example ID block can't be repeated , supplemental is given instead of it .
Now the first supplemental techniques …..
) :(intraligamentaryligament injectionPeriodontal
it's useful if conventional tech. is unsuccessful ,also if rubber dam is in its place, the
needle is inserted between the tooth & rubber dam . we can use standard or
pressure syringe [ the same efficiency ] and no need to bring pressure syringe ,also
we can use ( 30 ,27 ,25 ) G needle ,,short needle .
at the beginning we insert the needle in the mesial gingival marginat at 30 degree
to the sulcus {long axis of tooth}, the needle is supported & positioned with
maximum penetration into the sulcus , heavy pressure is slowly applied for (10-20)
sec ,also back pressure is very important u have to feel pressure during injection.
The injection is repeated on the distal surface at 30 degree also to the sulcus , we go
deep between crestal bone & the root of the tooth ,we give only small amount 0.2
ml on mesial & 0.2 ml on distal .

9. Mechanism of action :
The periodontal ligament injection causes anesthesia so a motion through the
cribriform plate into marrow spaces & into the vasculate in & around the tooth .
This means that the mechanism of action is not the pressure of solution ,the
solution goes into the marrow space & then into the vasculate around and inside
the tooth .so again the mechanism of action doesn't related to direct pressure on
the nerve .
The onset of anesthesia is RAPID –no waiting time - ,give the pt intraligamentary
injection then start to work immedietly & Don't Wait &
This type of anesthesia can be given as primary injection without the conventional
and it 's GOOD ,also if we use it as supplemental it's GOOD but not excellent .
Intraligamentary injection does not work in all cases, if it does not work u have to
repeat the injection .
Patients usually have mild discomfort after giving them the anesthesia from 14 hrs
to 3 days .

10. ous injection :eIntraoss
Other supplemental techniques the intraosseous method …
It allows placement of local anesthetic solution directly into the cancellous bone
adjacent to the tooth and it's excellent supplemental tech. but difficult to do here in
our clinic because we don't have the instruments .
It is a two - component system :
_ slow -speed hand piece driven perforator ,to perforate the cortical plate .
_ matching 27 gauge ultrashort injecting needle .
pic below shows the needle with the perforator
Technique :
The area of perforation and injection is only horizontal long of the buccal gingival
margin of the adjacent teeth and vertical long that passes through the interdental
papilla distal to the tooth to be injected .
Perforation site : approximately 2 mm below the intersection of these two lines
[vertical & horizontal] .
First give infiltration to the soft tissues then drill the bone with perforator then
give the injection SLOWLY from 1-2 min to give the injection.

11. The volume of solution is around half cartridge ((0.9 or 1))ml ,,notice in
intraligamentary we give (0.2,0.2) ml 0.4 ml ,,here we give more
solution (0.9 or 1) ml.
A student ask about the mental foramen under lower premolar ,,and the doctor
said that we are far away from it ,we give at 2mm below the intersection of
horizontal & vertical lines (the perforation site ).
Now moving to the complications of intraosseous injection ; perforator breakage is
one of the complications when we do perforation ,but it's rare case ,we remove it
hemostat .by
Selection of perforation site as we said it usually distal to the tooth but in the lower
2nd
molar it's mesial ,why ?
Because it's difficult to give distally, it's too far, u cannot control it and sometimes
u have the lower 3d molar tilted so it's difficult , if u can give it ,give it but in most
of the cases it's difficult .
 "what about the 3d molar ? " student ask
No,u can't give intraosseous for 3d molar it's very difficult .
Onset of anesthesia (as we said ); all the supplemental anesthesia => no waiting
period ,u give anesthesia & start drilling or treating .
The hemostat

12. Intraosseous anesthesia as primary injection is GOOD ,but as supplemental is
EXCELLENT .
: it fails when the anesthetic solution squirts out of theThe failure of anesthesia
perforation ,in this case u have to redo the perforation not the injection in the same
site .{this mean, I don't repeat the injection in the same perforation site ,,I make a
new one then inject into it }
and this is goodhouroneis less thanof the intraosseous if it primaryThe duration
,but usually we give conventional anesthesia first if it does not work then
supplemental .
not like the periodontal ligament anesthesia ,no or mildPostoperative problems
postoperative problems after intraosseous injection.
But in periodontal ligament injections most of the pts have postoperative problems.
….intrapulpal anesthesiaNow the last supplemental technique is
The indication of intrapulpal injection is the third choice of supplemental
techniques because it's very PAINFUL so don't start with intrapulpal anesthesia .
In the clinics we have to start with periodontal ligament injection ,unless
intraligamentary or intraosseous success then use the intrapulpal but
"Don't Start with intrapuplal anesthesia "
This pic shows the
intraosseous injection in the
perforation site which is 2mm
below the horizontal &
vertical lines .
The small structure below is
"mental foramen "

13. In intrapupal anesthesia the pt should be warned for it ,u should tell him/her that
he/she will feel a very sharp sensation ,because it is very very painful anesthesia .
Strong –back pressure has been shown to be the major factor in producing
anesthesia, u have to feel pressure while giving intrapupal anesthesia ,if did not it's
unsuccessful.
The duration also very short from 15-20 min so u have to be quick [all instruments
should be prepared before giving intrapulpal anesthesia this means give the
injection &start pulp extirpation immediately]
The technique:
Either u inject each canal{ if u open the access cavity and remove the roof of each
canal} ,or u can give the pulp chamber but u have to use a stopper to close the
access cavity and prevent the back flow of the anesthetic solution.
Standard syringe with short needle is used ,first bend the needle for easier insertion
then the needle is positioned inside the access opening & moved down to the canal
as deep as u can with maximum pressure applied slowly into the canal for 5-10 sec,
and then it will give pulpal anesthesia for (5-15) min .
N.B if there is no back pressure u have to go deeper or change the gauge of the
needle.
So back – pressure is the key point for intrapulpal anesthesia .
The pic on the right
represent intrapulpal
injection in each canal.
The pic on the left
represent intrapulpal
injection in pulp chamber.

14. And that’s all for today …. 
The dr. was just reading the slides so don't worry
Forgive me for any mistakes
Done by : Batool Smairan