Technique of Maxillary Anesthesia Flashcards
three types of LA injections
- local infiltration
- field blcok
- nerve block
local infiltration
small terminal nerve endings in the area of the dental tx will be flooded with LA
- the treatment occurs in the same area in which the LA is administered
- usually not just doing this one
field block
LA is deposited NEAR the larger terminal nerve branches so the anestherized area will be circumscribed
- tx occurs in an area away from the site of injection
- prevents passage of impulses to the CNS
- maxillary injections ABOVE THE APEX OF THE TOOTH
** getting coverage over a couple of teeth
Nerve block and examples
LA deposited close to a main nerve trunk, usually at a distance from the operative site
examples :
posterior superior alveolar (PSA), inferior alveolar, nasopalatine
bigger area – used in quadrant
supraperiosteal injection
most of the time we can use this when working in the maxilla and this is the MOST FREQUENT TECHNIQUE USED for obtaining anesthesia in the maxilla
indications for supraperiosteal injection?
Pulpal anesthesia of the maxillary teeth when tx is limited to one or two teeth
soft tissue anesthesia in a circumscribed area
contraindications for supraperiosteal injection?
- infection or acute inflammation in the area of injection
2. dense bone overlying apices of teeth
advantages of supraperiosteal injection?
- high success rate
- technically easy injection
- usually atruamatic
disadvantages of supraperiosteal injection?
- not recommended for larger areas (volume of LA – may end up using more so just do a block technique instead)
- positive aspiration (less than 1%)
land marks for a supraperiosteal injection?
- mucobuccal fold
- crown of the tooth
- root contour of the tooth
injection for supraperiosteal injection?
needle use?
area of insertion?
target area?
using a 25-27 gauge short needle
area of insertion - height of the mucobuccal fold above the apex of the tooth being anesthetized
target area- apical region of the tooth
orient the bevel of needle toward the bone
failures of anesthesia in supraperiosteal injection?
needle tip lies below the apex
needle tip lies too far from the bone
complications in supraperiosteal injection?
pain on needle insertion with the needle tip against the periosteum
Posterior Superior Alveolar Nerve Block areas anesthetized
PSA when used for pulpal anesthesia for the maxillary 3rd, second, and first molars is effective in 77- 100% of patients
- ** MB root of the 1st molar is not consistently innervated by the PSA nerve
- may nee supplemental injection to adequately anesthetize the max 1st molar
max first molar innervation with PSA?
MB root of the 1st molar is not consistently innervated by the PSA nerve – need supplemental LA as supraperiosteal injection to adequate the maxillary 1st
areas anesthetized in PSA
pulps of the max 3rd, 2nd, and first molars
buccal periodontium and bone overlying these teeth
indications to do a PSA
- when tx involves two or more maxillary molars
- when supraperiosteal injection is contraindicated
- when supraperiosteal injection has proven ineffective
contraindications for PSA
when the risk of hemorrhage is too great
bleeding disorders?
heart disorders that are on anti-coagulants?
advantages of PSA?
atruamatic
high success
minimum number of injections needed
minimizes he total volume of LA
disadvantages of PSA?
risk of hematoma
technique is somewhat arbituary – no use of landmarks
second injection is usually necessary for tx of 1st molars in 28% of patients
positive aspiration in how much of PSA?
3.1%
PSA block technique? needle use? area of insertion? target area? landmarks?
needle use? = 25- gauge or 27 gauge short
area of insertion? = height of mucobuccal fold above the maxillary second molar
target area?
landmarks = mucobuccal fold, maxillary tuberosity, and zygomaic process of teh maxilla
PSA technique - directions?
upward and inward
backward
upward - superiorly at a 45 degree angle to the occlusal plane
inward = medially toward the midline at a 45 degree angle to the occlusal plane
backward / posteriorly at a 45 degree angle to the long axis of the second molar
PSA technique - aspirate in?
two planes – rorate syringe barrel one-fourth turn and reaspirate
depth of PSA in normal sized adult?
depth of 16 mm in a normal size adult
Precaustions with PSA
depth of needle penetration should be checked – overextension increases the risk of hematoma – too shallow might still provide adequate anesthesia