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Maxillary Anesthesia I: Pulpal Anesthesia
super
321
Apex/
Spongy
Cortical
Mucogingiv
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242
Maxillary nerve
Pterygopalatine
nerve branches
(V
fossa
Posterior
ior alveolar
)
2
Figure14.1 Needle 1, short, buccal infiltrations (4% positive
aspirations); needle 2, longer, posterior superior alveolar nerve
branch blocks (5% positive aspirations); needle 3, longest,
maxillary nerve (V
) block in pterygopalatine fossa (13% positive
2
aspirations).
nerve
Periosteum
junction
bone
al
bone
Figure14.2 Insertion of needle immediately below the
mucogingival junction with the solution crossing the
periosteum, cortical, and spongy bone to reach the nerve at the
entrance to the dental apex.
Technique
inserted at a much greater height and wider angle to
reach the pterygopalatine fossa, greatly raising the risk of
hematoma and other adverse effects. This method anesthetizes molars, premolars, and the palate on the side
injected.
Buccal Infiltration
This technique has a number of synonyms: supraperiosteal
buccal infiltration (all modern techniques are supraperiosteal), buccal infiltration, and anesthesia of the plexus.
This is by far the technique most commonly used to anes-
thetize maxillary tooth pulp, given its simplicity, efficacy,
and safety. It consists essentially of administering the local
anesthesia around the teeth to be treated, crossing the periosteum, the cortical bone, and the trabecular or spongy
bone to reach the dental apex and anesthetize the pulp and
adjacent tissues (Figure14.2).
Zones Anesthetized
● Tooth (pulp and periodontal ligament) injected, often
extending to the adjacent mesial and distal teeth.
● Buccal cavity, including fibromucosa (alveolar mucosa,
gingiva, and interdental papillae), bone, and periosteum.
● Short (20–25 mm), 25G or 27G needle.
● Dentist’s and patient’s positions.
⚪ Dentist at 9:00 to 10:00 o’clock.
⚪ Patient in supine position with head slightly
hyperextended to enable the dentist to administer the
anesthesia to the anterior and posterior teeth on the right
side and turn the patient’s head as required if the anesthesia is to be administered to the posterior teeth on
the left side.
● Bring the roof of the buccal cavity in the area to be anes-
thetized into view with the non-
⚪ For anterior teeth (incisors and canines), pull the
injection hand.
upper lip upward and ask the patient to open their
mouth (Figure14.3).
⚪ For posterior teeth (premolars and molars), pull the
cheek and labial commissure outward and slightly
upward to firmly stretch the jugal mucosa (Figure14.4).
Ask the patient to half- close their mouth to prevent
the coronoid apophysis of the mandible from shifting
forward (and getting in the way) as it does when the
mouth is wide open (Figure14.5).
● Needle insertion.
⚪ With the non- injection hand stretch and tense the (lax,
mobile, dark) buccal alveolar mucosa and then insert
the needle; a tense buccal cavity is readily visible,
facilitating painless penetration. Insert the needle as
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Buccal Infiltration 243
Mucogingival junction
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Figure14.3 Insertion of needle alongside the mucogingival junction in anterior teeth, with the patient’s mouth wide open, pulling
the upper lip upward.
Figure14.4 Insertion of needle alongside the mucogingival junction in molars, pulling the labial commissure outward and upward,
and asking the patient to partially close their mouth.
close to the apex of the tooth to be treated as possible (key
to success), introducing the tip of the needle only
2–3 mm underneath the mucosa.
⚪ The periosteum and bone are rarely touched with this
technique but if that happens draw the needle back
slightly to avoid impact.
⚪ Inject immediately above the mucogingival junction
(line between the attached gingiva and the alveolar
mucosa) for the following reasons.
■ As the surface of the maxilla is buccally concave,
the surface of the bone is farther from the root
inthe apical direction, in the central incisors due
to the position of the anterior nasal spine and in the
molars to the position of the zygomatic apophysis of
the malar bone.
■ As the submucosa is less lax than the roof of the
buccal cavity due to the proximity of the attached
gingiva, when the needle is inserted immediately
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Maxillary Anesthesia I: Pulpal Anesthesia
244
ronoid
process
Figure14.5 Partially closed mouth in which the coronoid
process rises, leaving room to reach the molars buccally.
above the mucogingival junction the anesthetic
solution is kept in a smaller area in closer contact
with the bone, tending to diffuse to the apex. If it
were injected at the roof of the buccal cavity, it
would tend to diffuse to softer tissues and away
from the bone.
■ Since the injected liquid is stored a little beyond the
tip of the needle, the insertion site should always be
slightly mesial relative to the tooth.
● Aspire before injecting. Aspiration is positive in 2% of
anterior teeth and 4% of molars (Annex 22).
● Injection proceeds to minimal intervention (minimum
volume/minimum injection time) criterion. Injection
pain is greatly reduced with this four- step technique.
1) First inject only one or two drops of anesthetic solu-
tion within 1–2 seconds and wait 60 seconds after
withdrawing the needle to anesthetize the soft tissue
around the injection zone.
2) Inject another one or two drops at the same site (nor-
mally identifiable by tiny blood droplets caused by
the first insertion) during 1–2 seconds and wait
30
seconds after withdrawing the needle.
3) Inject a larger amount of anesthetic (about an eighth
of a cartridge or 0.25 ml) slowly within 7–10 seconds
and, after aspirating, wait 30 seconds after withdrawing the needle. Note that just a small amount is
injected to reinforce the preceding injections and
begin pulpal anesthesia.
4) After aspirating, slowly inject the full amount of
anesthesia envisaged at the same site, after aspiration.
Note: Clinical studies have shown that anterior maxillary (incisor) infiltrations are painful, only slightly
less than palatal infiltrations (hence heeding the
importance of minimal intervention criterion),
whereas infiltration in the maxillary molars is one of
the least painful techniques (Annex 23; Bataineh and
Al- Sabri2017). Another advantage is that anesthetizing the soft tissues (happily) fails to confirm patients’
expectation of a more painful second than first injection (Martin et al. 1994; Meechan and Day 2002;
Paschos et al. 2006; Badcock et al. 2007; Kuscu
etal.2014).
● Amount of anesthetic to be used. Clinical studies today
recommend slightly larger amounts than classical texts
to ensure good pulpal anesthesia (Mikesell et al.1987;
Premdas and Pitt Ford 1995; Brunetto et al. 2008;
Guglielmo etal.2011; Sreekumar and Bhargava2011).
⚪ In anterior teeth: a little less than a full 1.8- ml car-
tridge, 1.5
⚪ In posterior teeth: a full cartridge or slightly more,
1.8–2.5
Note: In children under 6–8
ml, for instance.
ml.
years, the dose should
be halved.
● The submucosa lump or blister forming must not be
touched to enable the anesthetic to spread across the periosteum, cortical, and spongy bone to reach the apex and
from there the nerve fibers in the teeth (Figure 14.2).
Massaging the blister forces the anesthetic to spread
along the pathway of least resistance, the lax soft tissues,
carrying it away from the injection site and lowering the
concentration at the target zone and hence the capacity
to diffuse toward the dental apex.
● Subjective symptoms of anesthesia. Soft tissue anesthe-
sia, defined by patients as dullness, numbing, tingling,
itching, pins and needles feeling, or fattening in the lip
(Table13.1, Chapter13) varies depending on the injection site.
⚪ In anterior teeth. Soft tissue anesthesia begins in the
upper lip, labial commissure, and even the ala nasi
within 2 minutes.
⚪ In posterior teeth. As labial anesthesia is scant, espe-
cially where molars are concerned, a waiting period of
at least 5 minutes must be allowed. Alternatively, some
clinicians insert a probe in the mucosa to determine
soft tissue anesthesia.
● Time needed for pulpal anesthesia. In 70% of individuals
anesthesia is effective in less than 2 minutes (Annex 21),
although the recommended waiting period is 5 minutes
from the time of injection. Where the minimal intervention
criterion is followed, a minute or more may be necessary.
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● Soft tissue anesthesia usually lasts 3–4 hours (200 min-
utes) (Annex 21), a fact which the patient should be notified of after treatment.
Efficacy ofthis Technique
Clinical studies have proven the efficacy of this technique
to be high (Table14.1), with success rates of 95% in posterior and 98% in anterior teeth in adults with a powerful
solution such as 4% articaine, 1:100
ml) (A-
100), and around 87% and 95% of a standard lido-
caine solution (L-
100). Palatal reinforcement with a small
amount of anesthetic solution (±0.25–0.3
000 epinephrine (10 μg/
ml) raises pulpal
anesthetic efficacy and duration, particularly in posterior
teeth with palatal roots (Aggarwal et al. 2011; Guglielmo
etal.2011; Ulusoy and Alacam2014).
Complications Specific tothis Technique
The most common of the very few complications associated are listed below.
1) Appearance of small, asymptomatic intraoral hemato-
mas in the submucosa that disappear spontaneously in
a few days and that are attributable to repeated needle
insertion in the same site as recommended for minimal
intervention.
2) Injection site inflammation in 2% of cases (Moore
et al. 2006), which also subsides spontaneously in a
few days.
3) Failure to anesthetize the pulp is uncommon with this
technique, as noted. In some individuals failure in the
central incisors may be due to thickening of the anterior
nasal spine and in molars to thickening of the zygomatic arch of the malar bone.
Factors That Lead toSuccess
1) The tooth. Poorer results are obtained with molars than
with anterior teeth (Cowan 1964; Certosimo and
Table14.1 Successful (%) pulpal anesthesia inanterior and
posterior teeth withbuccal infiltration (electrical pulp tester
assessment).
Archer1996) for two reasons: (i) cortical thickening at
the zygomatic crest and (ii) separation of the palatal roots.
2) The anesthetic solution. While 2% lidocaine, 1:100 000
epinephrine (L-
100) delivers good results, success rates
are higher with powerful solutions such as 4% articaine,
000 epinephrine (A- 100) or 2% lidocaine, 1:50 000
1:100
epinephrine (Lsolutions such as A-
50) (Annex 21). The use of powerful
100 is therefore preferred in adults,
given that in such cases the potency of the solution
enhances penetration and the capacity to cross the periosteum, cortical, and spongy or trabecular bone to reach
the dental apex and bathe the nerve fibers, intensifying
the effect and lengthening the duration of pulpal anesthesia (Annex 21).
3) The volume of solution injected. As clinical tests have
shown that overly small volumes lead to a higher number of failures (Mikesell et al.1987; Premdas and Pitt
Ford1995; Brunetto etal.2008), the volumes specified
above are preferred.
4) The waiting time. The recommended waiting time is
5
minutes after completing injection (Mikesell
etal.1987; Certosimo and Archer1996) (Annex 21).
Modified Cotton Roll Approach
Jorgensen and Hayden recommended using a cotton roll to
raise the success rate (Jorgensen and Hayden1970).
The technique is the same as specified above except
that a small cotton roll is placed at the roof of the buccal
cavity before injecting the solution and held firmly
against the mucosa with the non- injection index finger
or thumb. The needle is inserted between the roll and the
mucogingival junction, maintaining the pressure on the
roll during and for a few minutes after injection
(Figure14.6).
The aim is to create a nearly closed deposition area in the
lax alveolar soft tissue to hinder diffusion along that initially easier route (carrying it away from the injection site)
and force the solution to diffuse across the cortical layer of
the bone to the apices.
Anesthetic solution Anterior teeth 1
2% lidocaine + 1:100 000
epinephrine (L- 100)
4% articaine + 1:100 000
epinephrine (A- 100)
Source: Data from Annex 21.
Successful pulpal anesthesia (%)
ml First molar 1.8 ml
95 87
98 95
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Infraorbital Nerve Block
Infraorbital nerve block is not recommended for routine dental treatment (Kleier etal.1983; Roberts and Sowray1987;
Jastak etal.1995) and is consequently seldom used because
(i) the buccal infiltration alternative is simpler, safer, and
more effective and (ii) many patients reject the approach
psychologically for fear of injury to the eye (Jastak
etal.1995; Malamed2004).
Maxillary Anesthesia I: Pulpal Anesthesia
Cotton roll
Mucogingival junction
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246
Figure14.6 Cotton roll in the roof of the buccal cavity to trap
the anesthetic solution between it and the mucogingival
junction, forcing diffusion toward the periosteum, cortical, and
spongy bone.
The technique theoretically aims to fully block the
anterior and partially anesthetize the middle alveolar nerve
by diffusing the anesthetic solution across the infraorbital
foramen to anesthetize the incisors, canines, and premolars
on the side injected.
The technique has two variations, intraoral (the most
common) and extraoral or transcutaneous, normally used
by oral and maxillofacial surgeons. The drawback to the
extraoral approach is that it is more painful (Karkut
et al. 2010) and poses more local complications (Kleier
et al.1983; Karkut etal. 2010), although as it does not
involve the canine fossa, it is useful in infectious or inflammatory processes affecting the roof of the buccal cavity in
the zone (Jastak etal.1995; Malamed2004).
Uses
● Circumstances for using either the intraoral or the
extraoral approach.
1) Surgical operations on the anterior aspect of the max-
illa on the side injected, such as surgical extraction of
impacted canines, apicoectomies, epulis extractions,
and maxillary sinus surgery (Kleier et al. 1983;
Roberts and Sowray1987).
2) Multiple tooth treatments, for theoretically it calls
for a smaller volume of anesthesia, avoiding the need
for multiple injections in restorations and extractions (Kleier et al. 1983; Jastak et al. 1995;
Malamed2004).
3) After buccal infiltration failure in anterior teeth
(Kleier etal.1983; Roberts and Sowray1987; Jastak
etal.1995; Malamed2004).
● Additional circumstances for use of the extraoral
approach only.
1) Inflammation and infection of the canine fossa and
surroundings in which buccal infiltration is not
appropriate (Jastak etal.1995; Malamed2004).
2) Trauma to anterior teeth where the alveolar bone
must be repositioned and the soft tissue sutured
(Kleier etal.1983).
Zones Anesthetized
● Anesthesia of the anterior and middle superior alveo-
lar nerves.
⚪ Teeth, including pulp and periodontium of the canine,
first premolar and second premolar on the side
injected. The central and lateral incisors and the first
molar on the side injected are likewise anesthetized,
albeit only partially.
⚪ Buccal cavity, including fibromucosa (alveolar mucosa,
gingiva, and interdental papillae), bone and periosteum around incisors, canines and premolars on the
side injected.
⚪ Maxillary sinus, anterior and lateral walls and floor.
● Anesthesia of the peripheral branches of the infraorbital
nerve affects the skin on the upper lip, ala nasi, and
lower eyelid on the side injected.
Intraoral Technique
● Long (35–38 mm), 27G or 25G needle.
● Dentist’s and patient’s positions:
⚪ Dentist at 8:00–10:00 o’clock.
⚪ Patient in supine position with their neck slightly
extended. Mouth moderately open. If the neck is bent
rather than extended, the patient’s chest interferes
with the syringe.
● Location of the infraorbital foramen.
⚪ Ask the patient to look straight ahead. In 85% of indi-
viduals, the foramen lies on the imaginary line
joining the pupil and the longitudinal axis of the second premolar (Annex 2). The line also runs very close
to the labial commissure on the side injected
(Figure14.7).
⚪ With the non- injection index finger, feel the slight
depression on the rim of the orbit at the point crossed
by the imaginary line running from the pupil. That is
the zygomaticomaxillary suture, normally found at a
point two- fifths inward on the lower orbital rim
(Figure14.8).
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⚪ Run the finger downward from there along the lower
infraorbital rim for 5–10
mm until it reaches the infraorbital depression (infraorbital nocht, which is where the
infraorbital foramen lies) (Annex 2). Hold the finger in
that position, pressing gently (Kleier etal. 1983; Karkut
etal.2010).
Figure14.7 Infraorbital foramen on the imaginary line joining
the pupil (looking straight ahead) and the labial commissure.
● Retract the upper lip with the non- injection thumb to
view the anterior maxillary teeth and the plexus on the
buccal aspect of incisors, canines, and premolars, while
tensing the roof of the buccal cavity (Figure14.9).
● There are two possible approaches to the infraorbital
foramen.
1) The vertical or direct or second premolar approach,
deemed here to be the better of the two, for in 85%
of individuals the infraorbital foramen lies on or
near the extended second maxillary premolar axis
(Annex 2) (Figure14.8).
⚪ Insert the needle at the roof of the buccal cavity
over the second premolar with the bevel facing the
bone (so that when the anesthetic solution is
injected it diffuses toward the infraorbital foramen)
and separated from the alveolar bone by around
5
mm to prevent premature contact with the roof of
the canine fossa as the needle travels toward the
infraorbital foramen (Bennett 1984; Jastak
etal.1995) (Figure14.9).
⚪ Place the needle parallel to the longitudinal axis of
the second premolar and guide it gently toward the
infraorbital foramen underneath the tip of the
non-
injection index finger. The needle courses
along the second premolar cementoenamel junction (CEJ) to the infraorbital foramen for about
mm (Annex 2) or, if measured from the roof
30–35
of the buccal cavity, for around 15
mm (Jastak
etal.1995; Malamed2004).
Note: Remember that injection around premolars and molars is much less painful than around
anterior maxillary teeth (Annex 23).
Figure14.8 Infraorbital
foramen on the axis extending
upward from the second
maxillary premolar at a point
two- fifths inward on the lower
orbital rim.
Point 2/5 inward
on infraorbital rim
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Maxillary Anesthesia I: Pulpal Anesthesia
Separation from alveolar process
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248
Figure14.9 Non- injection index finger over the skin on the
infraorbital foramen as the thumb lifts the upper lip, keeping the
needle a few millimeters away from the alveolar process and
running it parallel to the axis of the second premolar (direct or
vertical approach).
Note: Remember that injections around the anterior
maxillary teeth are among the most painful, nearly as
painful as palatal injections (Annex 23).
Another variation is from the canine, a less oblique
and slightly shorter approach.
● The tip of the needle reaches the infraorbital foramen
underneath the tip of the non-
injection index finger. It
impacts the roof of the infraorbital foramen (lower rim
of the orbit), preventing penetration in the orbit. The
infraorbital foramen runs downward and medially
(toward the nose) in nearly 60% of individuals and downward only in 20% (Annex 2).
● Aspire before injecting: 1% of cases are positive (Karkut
etal.2010).
● Inject a 1.8- ml cartridge over the course of 40–60 seconds
(Berberich etal.2009; Karkut etal.2010). The index finger should feel the deposition. As the bevel faces the
bone, the anesthesia is distributed toward the entrance to
the infraorbital foramen.
● Massage the area after injection, pressing gently with the
index finger for a few seconds (Karkut etal. 2010) to
enhance diffusion of the solution inside the foramen.
● Subjective symptoms of anesthesia (numbness, tingling,
etc.) (Table13.1, Chapter 13) appear in 1–3
minutes in
the upper lip, nasi ala, and lower eyelid. Pulpal anesthesia is reached in 5–10 minutes (Berberich et al. 2009;
Karkut etal.2010) and the soft tissue remains anesthetized for 3–4 hours (Feige1978; Corbett etal.2010).
In a variation on this approach, which is nearly
direct, the reference is the first rather than the second
premolar (Malamed2004).
2) Oblique or from the midline or from the lateral
incisor.
⚪ Insert the needle at the roof of the buccal surface
in alongside the lateral incisor, obliquely, i.e. on
the imaginary line running from the mesial incisal
angle to the gingival distal angle, with the bevel
facing the bone (so that when the anesthetic solution is injected it diffuses toward the infraorbital
foramen) and separated from the alveolar bone by
around 5 mm to prevent premature contact with
the roof of the canine fossa as the needle travels
toward the infraorbital foramen.
⚪ Advance the needle obliquely and gently toward
the infraorbital foramen underneath the tip of the
index finger. This route is less direct and somewhat longer, with the needle running along 20 mm
of soft tissue (Bennett 1984; Roberts and
Sowray1987).
Extraoral Technique
● Needle. Either (i) short (20–25 mm) double- tip, cartridge-
like, caliber 27G or 25G, or (ii) short, strong insulin
syringe. Remember that the route is shorter and the needle has to penetrate the skin and firm subcutaneous tissue.
● Dentist’s and patient’s positions as in the intraoral
approach.
● Location of the infraorbital foramen. As in the intraoral
approach.
● Ask the patient to close their eyes for protection while
disinfecting the skin in the suborbital area and for psychological reasons because extraorbital injection of the
infraorbital foramen is not a pleasant sight.
● Insert the needle in the skin below the non- injection
index finger rests, marking the location of the infraorbital foramen.
⚪ Hold the needle with the bevel toward the skin so that
when injected the anesthetic solution diffuses toward
the infraorbital foramen (Kleier etal.1983).
⚪ As the foramen follows a downward and inward course
(Annex 2), place the needle at a site slightly inward of
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and lower than the mark on the skin at an angle of
around 45° and tilted slightly outward.
● Insert the needle in the skin and continue until touching
bone. Inject around 0.2
and wait 30
seconds before removing the needle (Kleier
ml to anesthetize the soft tissues
etal.1983; Roberts and Sowray1987).
● When re- inserting, use the needle as a probe to locate the
entrance to the infraorbital foramen or a site near it
(Karkut et al.2010). Push the needle in no more than
10
mm (Kleier etal.1983; Karkut etal.2010). Remember
that the soft tissue over the foramen is around 7
mm
thick and the needle must not penetrate into the foramen
more than 1–3
mm (Kleier etal.1983; Karkut etal.2010).
Do not try to penetrate the foramen, but merely to reach
a nearby site to prevent the risk of penetrating the orbit
and affecting the eye (Saeedi etal.2011).
● Aspire before injecting. Aspiration is positive in 1% of
cases (Karkut etal.2010).
● Inject the rest of the cartridge (1.6–1.7 ml) over the
course of 40–60
seconds. During this operation, the noninjection index finger should feel the deposition of the
solution underneath the skin. As the bevel faces the bone
the anesthesia is distributed toward the infraorbital
foramen.
● After injection massage and gently press the area with
the index finger for a few seconds (Karkut etal.2010) to
enhance diffusion of the solution toward the inside the
foramen.
● The subjective symptoms of anesthesia are as described
for the intraoral approach.
Efficacy ofthis Technique
As Table 14.2 shows, according to clinical trials pulpal
anesthesia is successful, on the side injected, in 25% of
maxillary incisors, in around 90% in canine and premolars,
and 60% in the first maxillary molar (Figure 14.10) after
injecting 1.8 ml of standard lidocaine solution (L- 100). The
pulp is anesthetized in around 3
minutes on average
(Corbett et al. 2010). The effect is most intense after
minutes.
5–10
Table14.2 also shows that the results with the intra-
and
extraoral approaches are very similar, although poorer
by- tooth than obtained with buccal infiltration
toothanesthesia.
Complications Specific tothis Technique
1) A facial hematoma may appear under the lower eyelid
in 2% of cases due to injury to the inferior facial vein or
some vascular nervous package in the infraorbital foramen (Phillips 1943; Berberich et al. 2009; Karkut
etal.2010). It disappears spontaneously in 10–14
days
(Berberich etal.2009; Karkut etal.2010).
2) Moderate to severe postoperative pain in the area in 1%
of cases, lasting normally 1–3
days (Berberich
etal.2009).
3) Temporary double vision (diplopia) in nearly 3% of
patients with the extraoral technique (Kleier etal.1983;
Karkut etal.2010), even one case with intraoral technique (Ceylan etal.2010), disappearing with the effect
of the anesthesia.
Table14.2 Successful (%) pulpal anesthesia withthe infraorbital nerve technique (electrical pulp tester assessment andstandard
anesthetic solutions L- 80 or L- 100).
Tooth
Central incisor (%) 40 15 15 11 15
Lateral incisor (%) 50 28 22 18 22
Canine (%) 100 85 92 93 92
First premolar (%) 100 82 90 89 87
Second premolar (%) 100 75 80 96 82
First molar (%) — 52 70 — 65
Amount injected (ml) 0.5 1.8 1.8 1.0 1.8
Solution injected L- 80 L- 100 L- 100 L- 80 L- 100
L- 80 → 2% lidocaine + 1:80 000 (12.5 μg/ml) epinephrine.
L- 100 → 2% lidocaine + 1:100 000 (10 μg/ml) epinephrine.
a
Using “the wand” (computer- controlled local anesthetic).
Feige (1978)
n=62
Intraoral Extraoral
Berberich etal. (2009)
n=40
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Karkut etal. (2010)
n=40
Corbett etal. (2010)
n=28
a
Karkut etal. (2010)
n=40
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250
Figure14.10 Efficacy of anesthesia: greatest in ruled area and
only partial in dotted area.
missing, it may impact the posterior side of the globe
and injure the retina, causing the following harm.
● Acute and immediate ocular pain (Weinand
etal.1997; Chan et al. 2011). In some cases pain is
absent but other symptoms appear several minutes
later (Saeedi etal.2011).
● Dilated (mydriasis) or immobile pupil or failure to
react to light (Chan etal.2011; Saeedi etal.2011).
● Loss of visual acuity and vision impaired by floating
spots (Chan etal.2011).
● Blood extravasation to the conjunctiva (ecchymosis)
(Saeedi et al. 2011) or avulsed or extruded orbit
(exophthalmos) (Chan etal.2011).
● Ocular infection (endophthalmitis) (Weinand
etal.1997).
All such cases require the intervention of an ophthalmologist. This rare complication may be more frequent in
the extraoral approach because the needle may be inserted
too horizontally, thereby entering the infraorbital canal
more deeply (Saeedi etal.2011).
Figure14.11 Needle penetration through the infraorbital
foramen at the posterior part of the eyeball. Source: Redrawn
from Saeedi (2011).
4) Needle penetration in the eyeball (Weinand etal.1997;
Chan etal.2011; Saeedi etal.2011) (Figure14.11). This
is very unusual because the needle normally impacts
the roof of the infraorbital foramen. Nonetheless, if the
needle crosses the roof of the foramen or if the roof is
Remarks
Infraorbital nerve block aims to anesthetize the one to four
branches of the anterior superior alveolar nerve that innervate incisors, canines, and occasionally the first premolar
(Chapter2). It is scantly effective for a number of reasons.
1) In the infraorbital foramen, the anterior superior alveo-
lar nerve branches lie at a distance of around 10–15
mm
from the infraorbital foramen (Table2.3, Chapter2) and
in some series 20% of individuals at over 20
mm
(FitzGerald and Scott1958; Heasman etal.1984). They
are therefore normally at a considerable depth and difficult to reach.
2) If the needle penetrates the infraorbital canal the risks
include (i) damaging the neurovascular bundle, sufficient reason to avoid this maneuver and confide in diffusion of the solution in the area around the infraorbital
foramen (Haglund and Evers 1985; Evers and
Haegerstam 1981) and (ii) penetrating the orbit and
affecting the eye (Weinand et al. 1997; Saeedi
etal.2011).
3) Accessory foramina appear in 15% of individuals, and
in 15% of those they may be multiple (Annex 2). These
accessory foramina may be located at a considerable
distance from the main infraorbital foramen (Kadanoff
etal.1970; Leo etal.1995) in up to 40% of individuals in
some series (Kadanoff etal.1970). These are important
findings because they explain why anesthetic block may
not be successful in the infraorbital foramen (Leo
etal.1995; Canan etal.1999).
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4) Anterior superior alveolar nerve block via the infraorbi-
tal foramen is insufficient to anesthetize incisor and
canine pulp because these teeth may be cross-
innervated
contralaterally or even by the nasopalatine nerve
(Hoffer1922a; Phillips1943; Phillips and Maxmen1941;
Cook 1949; Roda and Blanton 1994). Supplementary
buccal infiltration is therefore required.
In practice much of the efficacy of this technique depends
on the buccal diffusion of the anesthetic solution, since the
anterior wall of the maxilla (along which the anterior superior alveolar nerve branches course) is very thin (Cook1950a).
For that reason the teeth actually anesthetized are the canine
and premolars and surrounding tissue (Figure 14.10).
Generally speaking, then, the advantages of this technique
over simple buccal infiltration are nearly negligible.
Posterior Superior Alveolar
Nerve Block
Posterior superior alveolar nerve block (PSA) is also known
as zygomatic or tuberosity anesthesia because the idea is to
carry the anesthetic solution to the maxillary tuberosity.
This method is somewhat more complex than buccal
infiltration in molars because the needle must be inserted a
little higher and at an angle to skirt over the buccinator
muscle insertion, avoid the posterior wall of the maxilla
(tuberosity), and reach the foramina through which the
one to four branches of this nerve trunk transmit
(Figure14.12). The risk of hematomas due to injury to the
vessels in the zone is also higher. Recent clinical tests have
45°
Figure14.12 Lip separated with index finger and needle held
at 45° relative to the sagittal plane.
questioned its efficacy and utility, as the success rate for
anesthetizing maxillary molars is no higher than in simple
buccal infiltration (Padhye etal.2011; Al- Delayme2014).
Zones Anesthetized
● Teeth, including pulp and periodontium of the molars
and less frequently the premolars on the side injected.
● Buccal cavity, including fibromucosa (alveolar mucosa,
gingiva, and interdental papillae), bone and periosteum
in the buccal area around the molars as well as the premolars, although less effectively.
Technique
● Short (25 mm), 27G needle.
● Dentist’s and patient’s positions.
⚪ Dentist at 9:00–10:00 o’clock.
⚪ Patient in supine position with head slightly
hyperextended to enable the dentist to turn it slightly
to the left to anesthetize the right side or to the right to
anesthetize the left side.
● Examine the entire roof of the upper molar buccal cavity
with the non-
injection index finger to locate the osseous
bridge that protrudes from the zygomatic crest on the
malar bone (normally alongside the first maxillary molar).
● Retract the labial commissure outward and upward with
the non-
injection hand to firmly stretch the jugal mucosa
(Figure4.12).
⚪ Stretch the tissue intraorally with the index finger on
the right side and the thumb on the left.
⚪ The aim is to (i) bring the concavity of the buccal cavity
around the molars into view and (i) reduce any injectioninduced pain by inserting the needle in a tense mucosa.
● Increase the space for maneuvering by asking the patient
to partially close their mouth (Figure14.5). The result is
(i) greater labial commissure width and (ii) rearward
shift of the coronoid process of the mandible to keep it
from obstructing the operation.
● Insert the needle in the roof of the buccal cavity.
⚪ Behind the zygomatic crest of the malar bone, which is
usually the same as saying behind the second molar
(Figure14.1).
⚪ Orient the needle upward and as perpendicularly as
possible to the occlusal plane of the maxillary molars.
As a full 90° angle is not possible due to the presence
of the jugal mucosa, the needle should be posteriorly
oblique, which is also desirable.
⚪ Avoid the osseous wall to prevent the needle from
impacting or catching in the surface of the maxillary
tuberosity (outer and posterior wall of the maxilla).
⚪ Push the needle a few millimeters into the buccal cavity.
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