Home » INFRAORBITAL, INCISAL ANESTHESIA: INDICATIONS, POSSIBLE COMPLICATIONS AND THEIR PROPHYLAXIS. REMOVING THE TEETH OF THE UPPER JAW. TUBERAL, PALATINAL ANESTHESIA: INDICATIONS, POSSIBLE COMPLICATIONS AND THEIR PROPHYLAXIS. REMOVING THE TEETH OF THE UPPER JAW.

INFRAORBITAL, INCISAL ANESTHESIA: INDICATIONS, POSSIBLE COMPLICATIONS AND THEIR PROPHYLAXIS. REMOVING THE TEETH OF THE UPPER JAW. TUBERAL, PALATINAL ANESTHESIA: INDICATIONS, POSSIBLE COMPLICATIONS AND THEIR PROPHYLAXIS. REMOVING THE TEETH OF THE UPPER JAW.

June 11, 2024

INFRAORBITAL, INCISAL ANESTHESIA: INDICATIONS, POSSIBLE COMPLICATIONS AND THEIR PROPHYLAXIS. REMOVING THE TEETH OF THE UPPER JAW.
TUBERAL, PALATINAL ANESTHESIA: INDICATIONS, POSSIBLE COMPLICATIONS AND THEIR PROPHYLAXIS. REMOVING THE TEETH OF THE UPPER JAW.

Infraorbital Nerve Block

The infraorbital nerve block is often used to accomplish regional anesthesia of the face. The procedure offers several advantages over local tissue infiltration. A nerve block often achieves anesthesia with a smaller amount of medication than is required for local infiltration. In addition, unlike local tissue infiltration, nerve blocks can provide anesthesia without causing tissue distortion. Therefore, the infraorbital nerve block is a convenient alternative for situations such as facial lacerations in which tissue distortion would be unacceptable.

In general, regional anesthesia is ideal when the area of interest is innervated by a single superficial nerve. The infraorbital nerve supplies sensory innervation to the lower eyelid, the side of the nose, and the upper lip (see image below). Since the infraorbital nerve provides a considerably large area of sensory innervation, it is a prime candidate for a regional nerve block. A successful infraorbital nerve block provides anesthesia for the area between the lower eyelid and the upper lip.

Area of anesthesia for infraorbital nerve block.

The trigeminal nerve (cranial nerve V), provides sensory innervation to the face.^[1]The second division, the maxillary nerve (V2), exits the skull from the foramen rotundum. After giving off numerous branches, the maxillary nerve eventually enters the face through the infraorbital canal, where it ends as the infraorbital nerve (see image below). The infraorbital nerve supplies sensory branches to the lower eyelid, the side of the nose, and the upper lip.

Infraorbital nerve.

Indications

Wound closure
Pain relief
Anesthesia for debridement
Contraindication to general anesthesia

Contraindications

Any allergy or sensitivity to the anesthetic agent
Evidence of infection at the injection site
Distortion of anatomical landmarks
Uncooperative patient

Anesthesia

Most local anesthetic agents share the same basic chemical structure, which consists of an aromatic ring, linked to an intermediate chain, linked to a hydrophilic amine segment. The intermediate chain between the aromatic and hydrophilic segments is either an ester or an amide. The chemical structure of this intermediate group classifies the agent into the amide group or the ester group. This structural difference determines the pathway by which the agent is metabolized and its allergic potential. For example, amino amides undergo hepatic metabolism, whereas amino esters are metabolized in the plasma via pseudocholinesterases. Hydrolysis of amino ester compounds yields para -aminobenzoic acid (PABA), a well-known allergen, as an intermediate metabolite. Thus, amino esters are significantly more likely than amino amides to cause true allergic reactions.

Examples of commonly used esters include tetracaine, procaine, chloroprocaine, cocaine, and benzocaine. Members of the amide group include lidocaine, bupivacaine, mepivacaine, prilocaine, and etidocaine. A simple way to help decipher which drug belongs to which class is to remember that the letter i appears twice in the spelling of the amino amides.

The toxicities associated with local anesthetics are cardiovascular and neurologic. Methemoglobinemia can occur with use of these agents, though it is rarely clinically significant.

An infraorbital nerve block requires 1-3 mL of the chosen anesthetic agent.
Lidocaine (Xylocaine) is the most commonly used agent.

The onset of action for lidocaine is approximately 4-6 minutes.
The duration of effect is approximately 75 minutes.

Bupivacaine (Marcaine) is another frequently used anesthetic agent.

The onset of action of bupivacaine is slower than that of lidocaine.
The duration of anesthesia of bupivacaine is about 4-8 times longer than that of lidocaine.

The dose of anesthetic used in typical volumes for this procedure is not toxic.

Equipment

Luer-Lock syringe, 3 mL
Needle, 25-27 gauge, 1.5 in
Anesthetic agent (eg, lidocaine 1%)
Gloves (nonsterile and sterile)

Positioning

Supine on stretcher
Seated in ENT or regular chair

Technique

Intraoral approach

Obtain informed consent.
Apply cotton-tipped applicator soaked with topical anesthetic to the mucosa opposite the upper second bicuspid (premolar tooth) for 1 minute.
To palpate the infraorbital foramen, have the patient look straight ahead and imagine a line drawn vertically (sagittally) from the pupil down toward the inferior border of the infraorbital ridge.
Keep the palpating finger in place over the inferior border on the infraorbital rim for the remaining steps.
Retract the cheek and introduce the needle into the mucosa opposite the upper second bicuspid approximately 0.5 cm from the buccal surface (see images below).

Intraoral approach for infraorbital nerve block.

Infraorbital nerve block, intraoral approach.

Keep the needle parallel with the long axis of the second bicuspid until it is palpated near the foramen. (The approximate depth is 1.5-2.5 cm.) If the needle is extended too far superiorly and posteriorly, the orbit may be entered.

Once the needle is positioned properly, aspirate to ensure that the needle is not within a vessel.
Inject 2-3 mL of anesthetic solution adjacent to the foramen.
Take care not to inject into the foramen (which may result in swelling of the lower eyelid) by keeping the palpating finger firmly on the inferior orbital rim.

Extraoral approach

During the extraoral technique, the needle is in very close proximity to the facial artery. Because of this proximity, avoid adding vasoconstrictors to the anesthetic agent.
Use the previously described landmarks to locate the infraorbital foramen.
Prepare the skin overlying the infraorbital foramen with povidone iodine (Betadine) and sterile gauze.
Using sterile technique, insert the needle through the skin, the subcutaneous tissue, and the quadratus labii superioris muscle (see image below).

Technique for extraoral infraorbital nerve block.

Aspirate to ensure the needle is not within a vessel. The facial artery and vein are very close to the needle in this position.
Inject the anesthetic solution. The infiltrated tissue appears swollen.
Firmly massage this area for 10-15 seconds.

If the nerve block is unsuccessful, or if the exact location of the infraorbital foramen is unclear, a field block is a useful alternative.
To perform a field block, inject 5 mL of anesthetic solution into the upper buccal fold in an arc-shaped distribution. Massage the area for 10-15 seconds to speed the onset of anesthesia. Although this technique is not as precise as the previously discussed nerve block, it often accomplishes the same anesthetic effect.

Complications

Bleeding
Hematoma formation
Allergic or systemic reaction to anesthetic agent
Infection
Unintentional injection into artery or vein
Failure to anesthetize
Nerve damage
Swelling of the eyelid

Local Infiltration of the Maxillary Primary and Permanent Incisors and Canines

Technique:

Retract the cheek so the tissue of the mucobuccal fold is taut.
Apply topical anesthetic.
Orient the needle bevel toward the bone.
Penetrate the mucosa labial to the tooth to be treated close to the bone at the mucogingival margin with the syringe parallel to the long axis of the tooth. Advance the needle 2mm approximating the apex of the root.
Aspirate.
Inject a ¼- ½ carpule of anesthetic.
If it is necessary to anesthetize an adjacent tooth partially withdraw the needle and turn the needle in the direction of the indicated tooth in advance the needle until it approximates the apex.
Aspirate.
Inject ¼ – ½ carpule of anesthetic.
If palatal tissue anesthesia is necessary (extraction or incomplete anesthesia of the tooth due to accessory innervation from the palatal nerves), then one can inject anesthetic solution directly into the lingual tissue at the free gingival margin or one can insert the needle interproximally from the buccal and deposit anesthesia as the needle is advanced lingually.
The needle is withdrawn and recapped.
Wait 3-5 minutes before commencing treatment. The patient should exhibit numbness in the area of administration and absence of pain during treatment.

Anesthetization of the Maxillary Primary Molars and Premolars

The areas anesthetized are the pulps of the maxillary first primary molars (primary and early mixed dentition) and the first and second premolars and mesiobuccal root of the first permanent molar in the permanent dentition, as well as the buccal periodontal tissues and bone over these teeth. The injection is contraindicated if infection or inflammation is present in the area of administration.

Technique:

A 25 or 27 gauge, short needle is acceptable.
The area of insertion for the first primary molar is in between the apices of the roots of the tooth at the height of the mucobuccal fold. The area of insertion for the premolars is in an area between the two teeth.
Retract the cheek so the tissue of the mucobuccal fold is taut.
Apply topical anesthetic.
Orient the needle bevel toward the bone.
Penetrate the mucous membrane and slowly advance the needle until its tip is above the area between the apices of the first molar or above the apex of the second premolar.
Aspirate.
Slowly deposit ½ to 2/3 of a carpule of solution.
The needle is withdrawn and recapped.
Wait 3 to 5 minutes before commencing dental treatment. If the patient complains of pain it may be necessary to supplement anesthesia with a posterior superior alveolar nerve block.
A rare complication is formation of a hematoma at the injection site. If this occurs apply pressure with gauze over the site of swelling for a minimum of 60 seconds.

Posterior Superior Alveolar Nerve Block

For reasons already described, the posterior superior alveolar nerve block is used to anesthetize the second primary molar in the primary and mixed dentitions and the permanent molars in the mixed and permanent dentitions. The mesiobuccal root of the first permanent molar is not consistently innervated by the posterior superior alveolar nerve. Complete anesthesia of the tooth may need to be supplemented by a local infiltration injection.

The injection is indicated when a supraperiosteal injection is contraindicated (infection or acute inflammation) or when supraperiosteal injection is ineffective. It is contraindicated in patients with blood clotting problems (hemophiliacs) because of the increased risk of hemorrhage in which case a supraperiosteal or PDL injection is recommended.

Technique:

A 25 or 27 gauge short needle is acceptable.
The area of insertion is the height of the mucobuccal fold above and distal to distobuccal root of the last molar present in the arch.
Retract the cheek so the tissue of the mucobuccal fold is taut.
Apply topical anesthetic.
Orient the needle bevel toward the bone.
Insert the needle into the height of the mucobuccal fold over the last molar.
Advance the needle slowly in an:

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 molar) to a depth of 10-14mm.

Aspirate.
Slowly deposit ½ to 1 carpule of solution (aspirate several times while injecting).
The needle is withdrawn and recapped.
Wait 3 to 5 minutes before commencing with dental treatment. If anesthesia is incomplete supplement with a supraperiosteal or PDL injection.

Anesthetization of the Palatal Tissues

Palatal tissue anesthesia is necessary for procedures involving manipulation of the palatal tissues, i.e. extractions, gingivectomy and labial frenectomy. Unfortunately it is one of the most traumatic and painful procedures experienced by a dental patient during treatment. The following techniques should aid in reducing patient discomfort and in a small number of cases eliminate it entirely. Malamed recommends that the clinician forewarn the patient that there might be discomfort so they are mentally prepared. If the experience is atraumatic the patient bestows the “golden hands” award on the clinician. If pain is experienced the clinician can console the patient with “I’m sorry. I told you it might be uncomfortable” (avoid the “hurt” word).

The steps in atraumatic administration of anesthesia in all palatal areas are:

Provide adequate topical anesthesia (at least 2 minutes) in the injection area. The applicator should be held in place by the clinician while applying sufficient pressure to cause blanching.
Use pressure anesthesia at the injection site before and during needle penetration and solution deposition. The pressure is maintained with a cotton applicator with enough pressure to cause blanching.
Maintain control over the needle. The use of an ultrashort needle will result in less deflection and greater control. A finger rest will aide in stabilizing the needle.
Inject the anesthetic solution slowly. Because of the density of the palatal soft tissues and their firm adherence to the hard palate there is little room to spread during solution deposition. Slow injection reduces tissue pressure and results in a less traumatic experience.

Nasopalatine Nerve Block

The nasopalatine nerve innervates the palatal tissues of the six anterior teeth. If the needle is inserted into the nasopalatine foramen it is possible to completely anesthetize the six anterior teeth. However this technique is painful and not used routinely. The indications for a nasopalatine injection is when palatal soft tissue anesthesia is necessary for restorative therapy on more than two teeth (subgingival placement of matrix bands) and for periodontal and surgical procedures involving the hard palate. Local infiltration is indicated for treatment of one or two teeth. It is contraindicated when there is infection or inflammation in the area of the injection site.

There are two techniques; single penetration and multiple penetration. The single penetration consists of a single penetration of the mucosa directly into the incisive foramen relying on pressure anesthesia and slow deposition of anesthetic solution for pain management. Some clinicians feel this technique is still traumatic, especially for the pediatric patient and suggest a multiple penetration technique to minimize pain. The suggested technique is after buccal anesthesia is achieved with local infiltration, anesthetic solution is injected into the interdental papilla penetrating from the labial and diffusing solution palatally. The palatal tissue is sufficiently anesthetized to proceed with an atraumatic nasopalatine block.

Technique (single penetration):

A 25 or 27 gauge short or ultrashort needle may be used.
The area of insertion is the palatal mucosa just lateral to the incisive papilla (located in the midline behind the central incisors).
The path of insertion is approaching the incisive papilla at a 45 degree angle with the orientation of the bevel toward the palatal tissue.
Clean and dry the tissue with sterile gauze.
Apply topical anesthetic lateral to the incisive papilla for two minutes.
After two minutes move the cotton applicator directly onto the incisive papilla. Apply sufficient pressure so there is blanching.
Place the bevel of the needle against the blanched soft tissue at the injection site.
Apply enough pressure to slightly bow the needle. Deposit a small amount of anesthetic.
Straighten the needle and penetrate the tissue with the needle.
Continue to apply pressure with the cotton applicator while injecting.
Slowly advance the needle toward the incisive foramen while injecting until bone is contacted (about 5 mm).
Withdraw the needle 1mm and aspirate.
If negative, slowly deposit no more than a ¼ carpule of anesthetic.
The needle is withdrawn and recapped.
Wait 2-3 minutes before commencing with treatment.

Technique (multiple penetration)

A 25 or 27 gauge short or ultrashort needle is recommended.
There are 3 points of insertion:

The labial frenum between the maxillary central incisors.
The interdental papilla between the maxillary central incisors.
The palatal soft tissue lateral to the incisive papilla.

First injection: If labial anesthesia has not been achieved with labial local infiltration of the area the following injection is performed. If the area is anesthetized proceed to the second injection.

The path of insertion is into the labial frenum with the orientation of the bevel of the needle toward the bone.
Clean and dry area with sterile gauze.
Apply topical anesthetic for 1 minute.
Retract the upper lip to improve visibility.
Insert the needle into the frenum and deposit 0.3ml anesthetic solution over 15 seconds. The tissue may balloon. Anesthesia of the tissue should develop immediately.
Withdraw the needle

Second injection

Hold the needle at right angles to the papilla. The orientation of the bevel is not relevant.
Retract the lip to improve visibility.
Insert the needle into the papilla just above the crest of bone.
Direct it toward the incisive papilla on the palatal side of the interdental papilla while slowly injecting anesthetic solution. Do not penetrate through the palatal tissue.
When blanching is noted in the incisive papilla, aspirate.
If negative administer 0.3ml of anesthetic solution over 15 seconds.
Withdraw the syringe.

Third injection

Proceed as above for the single penetration injection, however application of topical anesthetic and pressure anesthesia is unnecessary.

Palatal anesthesia in the area of the canine may be inadequate due to overlapping fibers from the greater palatine nerve. To correct this, it may be necessary to supplement the anesthesia with local infiltration.

Greater Palatine Nerve Block

The greater palatine nerve block is useful for anesthetizing the palatal soft tissues distal to the canine. It is less traumatic than the nasopalatine nerve block because the palatal tissue in the area of the injection site is not as anchored to the underlying bone. It is indicated when palatal soft tissue anesthesia is necessary for restorative treatment on more than two teeth (insertion of subgingival matrix bands) and periodontal and oral surgery. It is contraindicated when there is infection or inflammation in the area of the injection site.

Technique:

A 25 or 27 gauge short needle may be used.
Locate the greater palatine foramen.

Place a cotton swab at the junction of the hard palate and the maxillary alveolar process.
Starting in the region of the maxillary first molar (or second primary molar in the primary dentition) apply pressure with the cotton swab while moving posteriorly.
The swab will fall into the depression created by the greater palatine foramen.

Prepare the tissue at the injection site, 1–2 mm anterior to the greater palatine foramen.
Clean and dry the area with a sterile gauze.
Apply topical anesthetic with a cotton applicator for two minutes.
Move the cotton applicator posteriorly so it is directly over the greater palatine foramen and apply sufficient pressure to blanch the tissue for 30 seconds.
Direct the syringe into the mouth from the opposite side of the mouth from the injection site at a right angle to the target area with orientation of the needle bevel toward the palatal soft tissue.
Place the bevel of needle gently against the blanched tissue and apply enough pressure to slightly bow the needle.
Deposit a small volume of anesthetic.
Straighten the needle and allow the needle to penetrate the mucosa, while depositing a small amount of anesthetic solution.
Slowly advance the needle approximately 8mm until palatine bone is contacted.
Withdraw 1mm and aspirate.
If negative, inject ¼ carpule of anesthetic solution over 30 seconds.
Withdraw the needle and recap.
Wait 2-3 minutes before commencing treatment.

Palatal anesthesia in the area of the first premolar may be inadequate due to overlapping fibers from the nasopalatine nerve. To correct this it may be necessary to supplement the anesthesia with local infiltration.

Local Infiltration of the Palate

Local infiltration of the palate provides anesthesia of the terminal branches of the nasopalatine and greater palatine nerves. The soft tissues in the immediate area of the injection site are anesthetized.

The indications for local infiltration are for achieving hemostasis during surgical procedures and when pain control of localized areas are necessary such as application of rubber dam or subgingival placement of matrix bands oo more than two teeth. It may supplement inadequate areas of anesthesia from nasopalatine and greater palatine alveolar blocks. It is contraindicated when there is infection or inflammation in the injection area. It can be a traumatic injection for the patient.

Technique:

A 25 or 27 gauge short or ultrashort needle may be used.
The area of insertion is the attached gingiva, 5-10mm from the free gingival margin in the estimated center of the treatment area.
Approach the injection site at a 45 degree angle with the orientation of the needle bevel toward the palatal soft tissues.
Clean and dry the injection area with sterile gauze.
Apply topical anesthetic for two minutes with a cotton applicator.
Move the cotton applicator adjacent to the injection site and apply sufficient pressure to blanch the tissue for 30 seconds.
Place the bevel of the needle against the blanched soft tissue and apply enough pressure to slightly bow the needle.
Inject a small amount of anesthesia and allow the needle to straighten and permit the bevel to penetrate mucosa.
Continue to apply pressure with the cotton applicator while injecting small amounts of anesthetic.
Advance the needle until bone is contacted (3-5mm) and inject 0.2-0.3 ml of anesthetic solution.
Withdraw and recap the needle.
If a larger area needs to be anesthetized, reinsert the needle at the periphery of the previously anesthetized tissue and repeat the procedure.
Treatment may be commenced immediately.

A multiple penetration technique may be used. Following the steps as described previously, after buccal or labial anesthesia is achieved, interpapilla injection is performed to attain palatal tissue anesthesia.

Anatomy

Atraumatic Injection Protocol

3 Main Types of Maxillary Injections:

1) Local Infiltration

2) Field Block

3) Nerve Block

Local Infiltration

• Incision (treatment) is done in the same area in which the local anesthetic was deposited (interproximal papilla before Scaling and Root Planing)

Nerve Block

• Local anesthetic is deposited close to a maierve trunk, usually at a site removed from the area of treatment (PSA, IANB, NPB)

Types of Injections

1) Supraperiosteal Injection

2) Intraligamentary (PDL) Injection

3) Intraseptal Injection

4) Intracrestal Injection

5) Intraosseous Injection

6) Posterior Superior Alveolar (PSA) Nerve Block

7) Middle Superior Alveolar (MSA) Nerve Block

8) Anterior Superior Alveolar (ASA) Nerve Block

9) Maxillary Nerve Block (2^nd Division)

10) Greater Palatine Nerve Block

11) Nasopalatine Nerve Block

12) Anterior Middle Superior Alveolar (AMSA) Nerve Block

13) Palatal Approach Anterior Superior Alveolar (P-ASA) Nerve Block

Maxillary and Mandibular Injections

The following are used in both arches:

• Supraperiosteal Injection

• Intraligamentary (PDL) Injection

• Intraseptal Injection

• Intraosseous Injection

Supraperiosteal Injection

1) Supraperiosteal Injection

ü Used for pulpal anthesia in maxillary teeth

ü Anesthetizes large terminal branches of the dental plexus

ü Greater than 95% success rate

ü 1 or 2 teeth

Supraperiosteal Injection

ü Dense bone covering the apices of the teeth can lead to failure

-maxillary molar of children (zygomatic bone

obscures)

–central incisor of adults (nasal spine obscures)

ü Negligible positive aspiration rate (less than 1%)

ü Should not be used for large areas (multiple sticks/large amount of local anesthetic solution must be used)

ü Technique à Supraperiosteal Injection

ü 1) 25 or 27 gauge short needle is recommended

ü 2) Insert needle at height of mucobuccal fold

ü over apex of desired tooth

ü 3) Apply topical anesthetic for at least one

ü minute

ü 4) Orient bevel toward bone; lift lip pulling

ü tissues taut

ü 5) Hold syringe parallel to long axis of the tooth

ü being anesthetized

ü 6) No resistance to penetration should be felt and no

ü patient discomfort

ü 7) Aspirate twice

ü 8) Deposit .6 ml (one-third of a cartridge) into tissue

ü over 20 seconds

ü 9) Do not allow tissues to balloon

ü 10) Wait 3 to 5 minutes to begin dental treatment

Problems/Failures

ü If tooth does not anesthetize the needle tip could be below the apex of the tooth resulting in inadequate anesthesia

ü If the needle lies too far from the bone then anesthesia will be inadequate because the solution was deposited in the soft tissue (lip)

ü The needle must be oriented toward the periosteum but should be managed properly to avoid tearing the highly innervated periosteum

Supraperiosteal vs. Infiltration

These two words are used incorrectly; what most practitioners refer to as an infiltration injection is actually a field block

Citing the ongoing economic crisis and growing competition from other insurers, Washington Dental Service will reduce reimbursement rates for all dental procedures by 15% starting June 1. Was it purely a business decision?

Posterior Superior Alveolar Nerve Block (PSA)

2) Posterior Superior Alveolar Nerve Block

v Highly successful nerve block with greater than 95% success

v Effective for maxillary 1^st, 2^nd and 3^rd molars and buccal periodontium

Mesiobuccal root of the maxillary 1^st molar is not consistently innervated by the PSA nerve

v Short dental needle is used for all but the largest of patients

v Average depth of soft tissue penetration is 16 mm (short needle is 20 mm in length)

v 28% of maxillary 1^st molars’ mesiobuccal roots are innervated by the middle superior alveolar nerve (MSA)

v When the risk of hemorrhage is too great as with a hemophiliac, you should use the supraperiosteal or PDL injections

v Patient should feel no pain with this injection because bone is not contacted and there is a large area of soft tissue into which the solution is deposited

v Positive aspiration risk is 3.1%

v Patient will often say that they do not feel numb; reason why is because they are accustomed to the intense feeling of anesthesia experienced by the IANB; reassure patient that you are going to make sure they are comfortable during the procedure

Technique à PSA Nerve Block

1) 25 gauge short needle is recommended

2) Insert needle at the height of the mucobuccal

fold above the maxillary 2^nd molar

3) Target area is the PSA nerve which is

posterior, superior and medial to the posterior

border of the maxilla

4) Apply topical anesthetic for at least one minute

5) Have patient open their mouth half way which

makes more room

6) Retract the patient’s cheek with mirror

7) Pull the tissues taut

8) Orient bevel toward bone

9) Insert needle at height of mucobuccal fold over the

2^nd maxillary molar

10) Advance needle upward, inward and backward

direction

11) Odd feeling of having no resistance whatsoever

12) Penetrating to an average depth of 10-14 mm is

adequate

13) Aspirate in two planes by rotating bevel one

quarter turn

14) Deposit 0.9 ml of a cartridge (1/2 cartridge)

15) Wait 3 to 5 minutes to start treatment

Advance the needle in one movement, not three

separate movements; usually atraumatic to most patients

Problems/Failures (PSA)

v Hematoma formation if needle is overinserted too far posteriorly

v Pterygoid plexus of veins leads to this hematoma

v Visible intraoral hematoma develops within minutes; bleeds until the pressure of the extravascular blood equals that of the intravascular blood which can result in a large, unsightly hematoma

Problems/Failures (PSA)

v Patients will usually claim that they do not feel any anesthesia which is not uncommon because patients caot reach this area to gauge their own level of anesthesia

v If using a long dental needle the maximum

insertion should be one-half on its length or

16 mm

Middle Superior Alveolar Nerve Block (MSA)

3) Middle Superior Alveolar Nerve Block

v Middle Superior Alveolar Nerve is not present in 28% of the population

v When the infraorbital nerve block fails to provide anesthesia to teeth distal to the maxillary canines, the MSA is indicated

v MSA provides anesthesia to 1^st and 2^nd premolars and mesiobuccal root of maxillary 1^stmolar; anesthetizes buccal periodontium and bone

v If MSA is absent the premolars and mesiobuccal root of maxillary 1^st molar is innervated by the ASA

v Positive aspiration risk is less than 3% (negligible)

v Infraorbital nerve block can block 1^st premolar, 2^nd premolar and mesiobuccal root of the maxillary 1^st molar if you need an alternative block when the MSA is not adequate

Technique à MSA Nerve Block

1) 25 or 27 gauge long or short needle

2) Insert needle at the height of the mucobuccal

fold above 2^nd maxillary premolar

3) Target is the maxillary bone above the

apex of the 2^nd maxillary premolar

4) Orient bevel toward bone to avoid

tearing periosteum

5) Apply topical anesthetic for one minute

6) Pull tissues taut

7) Penetrate tissues placing bevel of needle

well above the apex of the 2^nd maxillary

premolar

Technique– Middle Superior Alveolar Nerve Block

8) Aspirate

9) Slowly deposit 0.9-1.2 ml of solution

10) Wait 3 to 5 minutes before starting

treatment

Problems/Failures MSA

v Anesthetic not deposited above the apex of the 2^nd premolar

v Solution deposited into the soft tissue too far from the periosteum (lip)

v Hematoma may develop; Dentist should apply pressure to the area with gauze for at least sixty (60) seconds; up to 2 to 3 minutes

Middle Superior Alveolar Nerve Block

Anterior Superior Alveolar Nerve Block (ASA)

q Highly successful extremely safe block that causes hesitation in most clinicians

q Provides profound pulpal and soft tissue anesthesia from the maxillary central incisor distal to the premolars in 72% of patients

q Used in place of the supraperiosteal injection

Uses less anesthetic solution than the supraperiosteal injection

Supraperiosteal à 3.0 ml solution

ASA à 1.0 ml solution

#1 fear is damage to the patient’s eye which is unfounded

Also known as the Infraorbital Nerve Block which is inaccurate

Failed ASA is just a supraperiosteal injection over the 1st premolar

Areas Anesthetized à ASA Nerve Block

1) Pulp of the maxillary central incisor through the

canine

2) 72% of patients have premolars and mesiobuccal

root of 1^st molar anesthetic

3) Buccal periodontium and bone of the above teeth

4) Lower eyelid, lateral aspects of the nose and upper

lip

When Do I Use This Block?

1) Dental procedures involving more than

one tooth, i.e., central and lateral incisor

2) Inflammation/Infection precluding the use

of the supraperiosteal injection

3) Ineffective supraperiosteal injections due

to dense cortical bone

Technique à ASA Nerve Block

1) 25 gauge long needle is recommended

2) Insert needle at the height of the mucobuccal fold

over the 1^st premolar

3) Target: Infraorbital Foramen

4) Landmarks: Infraorbital Notch, Mucobuccal fold,

Infraorbital Foramen

5) Apply topical anesthetic for at least one minute

6) Feel the infraorbital notch moving your finger

down the notch palpating the tissues gently; the

outward bulge is the lower border of the orbit

which is the roof of the infraorbital foramen;

continue the finger inferiorly until a depression

is felt which is the infraorbital foramen

7) Maintain pressure over the foramen while

inserting the needle down the long axis of the

1^st premolar

8) Advance the needle slowly until bone is contacted

gently which is the upper rim of the infraorbital

foramen

9) 16 mm total advancement of needle;1/2 of long

needle length

10) Estimate the distance between the infraorbital

foramen and mucobuccal fold

11) Aspirate

12) Deposit 1.0 ml of anesthetic solution

13) Administrator can feel the anesthetic expanding

the tissue with finger tip

14) Maintain finger pressure over the foramen for

at least one minute to disperse the anesthetic

solution

15) Needle should not be palpable in most patients

16) Wait 3 to 5 minutes for anesthesia to result

Problems/Failures (ASA)

q Failure is from the needle deviating to the medial or lateral away from the infraorbital foramen

q Failure to reach the infraorbital foramen will result in anesthesia of the lateral side of the nose, upper lip and lower eyelid but not the teeth

q Hematoma formation can result although rarely; apply pressure to area for 2 to 3 minutes; at least 60 seconds

Palatal Anesthesia

Palatal Anesthesia

v Easily one of the most traumatic experiences for dentists due to the pain that is sometimes elicited from the patients

v Palatal injections can be administered atraumatically

STEPS– Results in painless palatal injections

1) Apply topical for two minutes

2) Apply pressure to site both before and

during deposition of the solution

3) Deposit solution slowly

5 PALATAL INJECTIONS

1) Anterior (Greater) Palatine Nerve Block:

no pulpal anesthesia

2) Nasopalatine Nerve Block: no pulpal anesthesia

3) Local Infiltration: no pulpal anesthesia

4) P-AMSA: pulpal and soft tissue

5) P-ASA: pulpal and soft tissue

Greater Palatine Nerve Block

GP Nerve Block (soft tissue and bone only)

Anesthetizes palatal soft tissue distal and medially to the canine

(posterior portion of the palate)

Tissues around the Greater Palatine Foramen are able to accommodate a larger volume of solution than the tissue in the vicinity of the Nasopalatine Foramen à less patient discomfort

Indications for palatal injections:

1) Scaling and root planing

2) Subgingival restorations

3) Deep placed matrix bands

4) Extractions (oral surgery)

Technique à Greater Palatine Nerve Block

1) 27 gauge short needle

2) Insert needle in soft tissue slightly anterior

to the greater palatine foramen

3) Target is the greater palatine nerve as it

passes from the foramen between the soft

tissue and bone of the hard palate

Locate the Greater Palatine Foramen:

-use cotton swab/mirror handle

-place a cotton swab at the junction of the

maxillary alveolar process and the hard palate

-press firmly into tissues moving posteriorly

from the maxillary 1^st molar

-swab “falls” into the depression of the

greater palatine foramen

4) Foramen is most often located distal to the

2^nd maxillary molar

5) Apply considerable pressure to cotton swab in area of foramen until a noticeable ischemia occurs; hold pressure for 30 seconds before injection

6) Continue to apply pressure throughout the injection with the cotton swab

7) Slowly advance the needle until bone is gently contacted

8) Depth of penetration is usually less than 10 mm

9) Aspirate

10) Deposit solution very slowly

Do not enter the greater palatine canal

There is no reason to have the needle penetrate the canal

There is no negative repercussion except post-operative pain

Nasopalatine Nerve Block

Nasopalatine Nerve Block à (soft tissue and bone only)

Ø Considered by many to be the most traumatic, painful injection of all the dental injections

Ø Most important injection to follow the protocol about to be explained

Ø Anesthetizes the anterior portion of the hard palate (soft and hard tissues) from the mesial of the left premolar to the mesial of the right premolar

Ø Use this injection for the same reasons as Greater Palatine Nerve Block

Ø Target area is the incisive foramen beneath the incisive papilla

Technique à Nasopalatine Nerve Block

1) 27 gauge short needle is recommended

2) Insertion point: palatal mucosa just lateral to the incisive papilla

3) Approach the injection site at a 45 degree angle

4) Apply topical anesthetic for two minutes

5) Apply considerable pressure to the incisive papilla until ischemia

6) Continue to apply pressure to the cotton applicator tip while injecting

7) Advance the needle until bone is gently contacted

8) Depth of needle penetration is usually 5 mm

9) Slowly deposit ¼ cartridge over a 30 second interval

10) Wait 2-3 minutes for anesthesia

Other Than P-ASA and Maxillary Nerve Blocks

There is no reason to enter the Greater Palatine Foramen or the Nasopalatine Foramen when providing these injections do not advance needle more than 5 mm into the incisive canal because it could enter the floor of the nose causing infection

Back Spray

During palatal injections, the pressure generated within the syringe will cause the solution to spray into your mask/face; always wear the appropriate safety glasses and mask when giving any injection

regardless of how trivial it may seem at the time 2^nd Example of Nasopalatine Injection

Techniqueà 2^nd Example of Nasopalatine Injection

Insertion Points:

1) Labial frenum; midline of maxilla (0.3 ml over 15 seconds)

2) Interdental papilla of #8 and #9 (0.3 ml over 15 seconds)

3) Palatal soft tissues lateral to the incisal papilla (contact bone)

Important Points:

• Topical and pressure anesthesia on the palate are not necessary because the first injection anesthetized the palatal tissues

• Contact bone on the 3^rd injection (incisive papilla) only

• Interdental papilla between maxillary central incisors is sore for a few days

• Greater palatine nerve may overlap and lead to inadequate anesthesia of the canine and 1^st premolar

Local Infiltration of the Palate

v Anesthetizes the terminal branches of the Greater Palatine Nerve and Nasopalatine Nerve

v Anesthetizes the soft tissue in the immediate vicinity of the injection

Indications for Palatal Anesthesia:

v 1) Hemostasis during procedures of a minimal area of tissue

v 2) Palatogingival pain control for rubber dam clamps, retraction cord placement and small surgical procedures

Important Points:

v -Gate control method (inhibitory neuron prevents the

v projectioeuron from sending signals to the brain

v (gate is closed)) of pain removal is used with

v -these injections using a cotton swab for pressure

v resulting in blanching tissue

v -Target area is the palatal tissue 5 to 10 mm from the

v free gingival margin

v -Masticatory mucosa of the hard palate is only

v 3 to 5 mm thick

v -Palatal Infiltrations are safe areas anatomically to

v deposit anesthetic

P-ASA

P-ASA à Palatal Approach Anterior Superior Alveolar Nerve Block

• Described in the 1990s by the inventors of the CCLAD systems

• Comparative to the Nasopalatine Nerve Block

• Insertion: lateral point of the incisive papilla but the big difference:

NEEDLE TIP IS POSITIONED IN THE

INCISIVE CANAL

• Deposit 1.4 – 1.8 ml of solution at

0.5 ml per minute

• Primary method of achieving bilateral pulpal anesthesia of the maxillary anterior six teeth; anterior palatal 1/3^rd

• Provides profound soft tissue anesthesia of the gingiva and mucoperiosteum

• Soft tissue of the facial attached gingiva is achieved anterior to the maxillary anterior six teeth

• P-ASA is the 1^st injection to produce bilateral pulpal anesthesia of the maxillary anterior six teeth from a single injection

MAIN POINT OF THIS INJECTION:

P-ASA is designed to provide pulpal anesthesia of the maxillary anterior six teeth in addition to the facial gingival soft tissue and mucoperiosteum

it does not anesthetize the lip as with the regular mucobuccal fold approach; esthetic Dentistry can then be assessed without dealing with lip anesthesia when smiling

• Palatal approach allows anesthesia to be limited to the subneural plexus for the maxillary anterior teeth and nasopalatine nerve

• Minimum volume for injection is 1.8 ml (full cartridge) over 0.5 ml/minute

• Insert needle very slowly

• 4% anesthetics should have volume reduced by ½ (Prilocaine/Articaine)

• Do not use 1:50,000 epinephrine

• May need supplemental mucobuccal fold injections for canines because of their very long roots

• Palatal ulcers develop from ischemia

1-2 days after treatment and are self-

limiting; healing occurs in 5-10 days

Technique à P-ASA

1) 27 gauge short needle is recommended

2) Insert needle just lateral to the incisive papilla in the papillary groove

3) Target is the nasopalatine foramen

4) Needle held at 45 degree angle to the palate (same as central incisors)

5) Insert needle 6 to 10 mm; if resistance is found do not force needle

6) Insert needle 1-2 mm every 4-6 seconds while administering solution

7) Resistance means you have to reinsert the needle; careful of nose floor

8) Aspirate

9) Deposit 1.8 ml of anesthetic solution very slowly 0.5 ml/minute

10) Patient may feel “needle shock” very disturbing to patient

Maxillary Nerve Block

1) Greater Palatine Approach

2) High Tuberosity Approach

q Also known as a 2^nd Division block

q Anesthetizes the maxillary division of the trigeminal nerve

Areas Anesthetized:

1) Pulpal anesthesia of all teeth on the side of injection (ipsalateral)

2) Buccal periodontium and bone on the side of injection

3) Soft tissues and bone of the hard palate/soft palate medial to midline

4) Skin of lower eyelid, side of the nose, cheek and upper lip

q It would require 4 other injections to get the effect of the Maxillary Nerve Block i.e., PSA, Infraorbital, Greater Palatine and Nasopalatine

2 Approaches:

1) Greater Palatine Approach

2) High Tuberosity Approach

1) Greater Palatine Approach Technique

ü 25 gauge long needle recommended

ü Insert into palatal soft tissue over greater palatine foramen

ü Target is the maxillary nerve as it passes through the Pterygo-palatine Fossa; the needle passes through the Greater Palatine Canal to reach the Pterygopalatine Fossa

ü Find the foramen by using a cotton swab until it “falls into” the foramen

ü Most often found at distal of the maxillary 2^nd molar

ü Topical anesthetic for at least two minutes

ü Inject into the area adjacent to the Greater Palatine Foramen in order to block the nerve before probing into the actual foramen itself

1) Greater Palatine Approach Technique

ü Remember to apply constant pressure into this area until the tissue blanches which will lessen the discomfort of the needle penetration

ü Probe gently for the foramen with the needle tip at a 45 degree angle

ü After finding the canal advance the needle 30 mm

ü 5 to 15% of foramens have boney obstructions, so if you encounter an obstruction do not force the needle, try again then abort

1) Greater Palatine Approach Complications

ü Penetration of the orbit leading to a myriad of complications

§ periorbital swelling or proptosis (bulging eye)

§ block of 6^th cranial nerve producing diplopia (double vision)

§ Retrobulbar (behind the eye) hemorrhage, corneal anesthesia

§ optic nerve anesthesia à loss of vision

Penetration of the nasal cavity (medial wall of the pterygopalatine fossa is paper thin):

-patient complains of something draining down their throat

-large amounts of air will be aspirated into the cartridge

Maxillary Nerve Block 2^nd Approach

2) High Tuberosity Approach

ü 25 gauge long needle recommended

ü Insert to the height of the mucobuccal fold distal to the 2^nd molar

ü Target is maxillary nerve as it passes through the pterygopalatine fossa

ü Superior and medial to the target site of the PSA

ü Again, advance the needle to a depth of 30 mm

ü Upward, inward and backward direction same as PSA

ü Resistance should not be felt, if it is, the angulation is too medial

ü At 30 mm the needle tip should lie within the pterygopalatine fossa

ü Aspirate several times and inject 1.8 ml (one cartridge) slowly

2) High Tuberosity Approach Complications

ü Hematoma develops rapidly if the maxillary artery is punctured with the needle tip

Thin, porous substance of the maxillary bone allows for rapid diffusion of solutions into the cancellous bone

Most Dentists rely solely on the supraperiosteal injection to provide anesthesia in the maxilla

PSA and ASA combined can deliver safe anesthesia to virtually all patients requiring maxillary anesthesia

Universal:

-applying topical anesthetic for

one minute

-proper patient positioning

-aspiration

-making the needle safe after each injection with the scoop technique

Nerve Block

When anesthetizing a quadrant is necessary, a maxillary nerve block may be appropriate.

The indicated site (green dot) is in a depression in the alveolar mucosa surrounded by the buccal surface of the maxilla, zygomatic process of the maxilla, and the operator’s finger. A long needle penetrates at the indicated site angled medially, posteriorly, and superiorly, advancing to half its length along the posterior border of the maxilla.

Dental hygienists should periodically review the maxillary nerve, its branches, and techniques available to achieve anesthesia of the maxilla. It’s no secret that, prior to root planing, many people dread the injections more than the procedure. By offering an alternative that reduces the number of injections, both clients and practitioners can look forward to a less stressful procedure.

Anesthesia of the maxillary division of the trigeminal nerve is a well-known procedure described by Malamed that can use either of two methods. In one technique, the practitioner must find the greater palatine foramen and pass the needle through the greater palatine canal. This is difficult, and occasionally the canal is impassable. The other technique described by Malamed is easier and calls for advancing the needle posterior and superior to the maxillary tuberosity. While the latter technique may be easier, there is a higher risk of puncturing the pterygoid venous plexus or maxillary artery in the pterygomaxillary fossa. In both cases, for an average size adult the needle must pass through 30 mm of soft tissue to reach its destination in the pterygomaxillary fossa.

Dental anesthesia for maxillary structures is typically learned by anesthetizing each of the branches distal to their separation from the maxillary nerve. If the maxillary nerve is not anesthetized before it branches off, as many as five nerve blocks may be needed to achieve thorough anesthesia of a maxillary quadrant. These blocks are:

• Posterior superior alveolar nerve (injected near the posterior surface of the maxilla)

• Middle superior alveolar nerve (injected above the second premolar)

• Anterior superior alveolar nerve (injected at the infraorbital foramen above the canine or first premolar)

• Greater palatine nerve (injected at the greater palatine foramen medial to the second molar)

• Nasopalatine nerve (injected at the incisive foramen, behind the central incisors)

In many cases, anesthetizing an entire quadrant is unnecessary and may seem excessive to a client who is having only one or two teeth treated. It is possible to anesthetize a smaller area with sufficient depth and duration. In these cases, nerve block anesthesia in one of the branches of the maxillary nerve is appropriate.

Also, many practitioners are afraid to use a maxillary nerve block due to the proximity of the nerve to blood vessels in the pterygopalatine fossa. Yet, after several experiences of achieving significant anesthesia of several maxillary nerve branches following administration of anesthetics intended for the posterior superior alveolar nerve block, I wonder about the safety of achieving sufficient analgesia of oral structures innervated by the maxillary nerve block.

If we can do this, we can save time and trauma to clients by using fewer injections and less anesthetic.

This is particularly important to clients at high risk of adverse reaction to local anesthetics. If the maxillary block fails to achieve sufficient analgesia, areas that need additional injections will receive them at the first attempt to anesthetize the tissues through blocks of the maxillary nerve branches. The injection intended for the maxillary nerve will provide anesthesia for the posterior superior alveolar nerve.

Sensory neuron cell bodies of the trigeminal nerve are in the trigeminal ganglion. This ganglion is known by two other names – the Gasserian ganglion and the semilunar ganglion (due to its crescent shape). The trigeminal ganglion is in a pouch of dura mater known as the trigeminal cave or Meckel’s cave, which is located in a depression on the petrous portion of the temporal bone within the middle cranial fossa.

Sensory and motor nuclei and cell bodies of proprioceptive nerves of the trigeminal nerve are in the pons. The sensory and motor nuclei of the trigeminal nerve are at a level below the superior cerebellar peduncle to the level of the middle cerebellar peduncle, and the nerve exits the pons near the middle cerebellar peduncle. Nerve cells that form synapses in the sensory nuclei transmit tactile, temperature, and pain sensations.

The trigeminal nerve is recognized as three distinct divisions – ophthalmic (V1), maxillary (V2), and mandibular (V3). Each division of the trigeminal nerve passes through a different foramen to leave the skull and innervate its designated location. V1 passes through the superior orbital fissure, and V3 through the foramen ovale. After it provides a middle meningeal nerve to innervate the dura mater and passes anteriorly from the trigeminal ganglion, V2 passes through the foramen rotundum within the greater wing of the sphenoid bone. At that point, V2 is in the most superior part of the pterygopalatine fossa. It passes anteriorly between the sphenoid and palatine bones, then laterally along the posterior surface of the maxilla. While in the pterygopalatine fossa, V2 has branches to the sphenopalatine ganglion and the zygomatic and posterior superior alveolar nerves. Nerves from the sphenopalatine ganglion innervate the orbit of the eye, the hard and soft palate, and parts of the nasal cavity, palatine tonsil, nasopharynx, and ethmoid sinuses. The zygomatic nerve goes further into the zygomaticofacial and zygomaticotemporal nerves, and supplies skin over the zygomatic process and anterior part of the temple.

The maxillary nerve continues through the inferior orbital fissure, at which point it becomes the infraorbital nerve, continues along the infraorbital groove, and reaches the face through the infraorbital canal, which ends at the infraorbital foramen. The trigeminal nerve carries branchial motor nerves originating from the pons; however, those efferent nerves travel along V3. Visceral motor nerves originating from other cranial nerves travel with all divisions of the trigeminal nerve, but are not considered part of the trigeminal nerve.

The maxillary nerve has several branches that play a major role in pain management during oral health care procedures.

• Posterior superior alveolar nerve (branches off in the pterygopalatine fossa, runs inferiorly along the posterior border of the maxilla, and passes through that surface to innervate the maxillary sinus, molars, buccal gingiva, and cheek)

• Middle superior alveolar nerve (branches off from the infraorbital nerve within the infraorbital fissure, passes lateral to the maxillary sinus, and innervates the first molar, premolars, buccal gingiva, and cheek)

• Anterior superior alveolar nerve (branches off from the infraorbital nerve in the infraorbital canal, passes anterior to the maxillary sinus, and innervates the anterior teeth, labial gingiva, lip, and parts of the nose)

• Ganglionic branches (pass through the pterygopalatine ganglion to innervate the palate)

Bergman, Afifi, and Miyauchi describe some variations of the maxillary nerve. These include:

• Missing middle superior alveolar nerve

• Separate nerve branch parallel to the infraorbital nerve supplying the upper lip

• Bifid maxillary nerve

• Posterior superior alveolar nerve innervating areas normally covered by the long buccal nerve

• Branches from the sphenopalatine ganglion supplying the abducens, optic, or ciliary nerves

• Various exchanges of nerve coverage among zygomaticofacial, zygomaticotemporal, infraorbital, and lacrimal nerves

Dental hygienists want a comfortable setting in which to perform their procedures. At the same time, many clients are not accustomed to the idea that a dental hygiene procedure might need to be uncomfortable to be effective. Multiple injections for pain control during a hygiene visit may be a surprise to someone whose experiences with dental hygienists have not addressed periodontal disease. Offering the smallest number of injections necessary for proper treatment helps the dental hygienist maintain rapport, keep clients on their maintenance schedules, and keep the lines of communication open to educate clients about treatment and home care.

A TECHNIQUE

The following technique has been successful at achieving sufficient analgesia with few instances of positive aspiration and no instances of hematoma.

▲ Apply topical anesthetic to the area of intended initial penetration of the needle

▲ Assemble syringe with the chosen anesthetic and a long (32 mm) needle

▲ Identify landmarks: alveolar mucosa at the maxillary mucobuccal fold, buccal surface of maxilla, zygomatic process of maxilla

▲ Open the client’s mouth no more than half way and have the mandible in lateral excursion to the side of the injection. Additional improvement to access can be achieved by having the client turn his/her head to the side opposite the injection site

▲ Palpate the posterior surface of the zygomatic process where it meets the buccal surface of the maxilla using the index finger of the non-injecting hand

▲ Slide the finger posteriorly and laterally from the zygomatic process until a depression in the alveolar mucosa is visible between the finger and zygomatic process

▲ In a straight path, direct the needle in a posterior, superior, and medial direction, maintaining its position as close as possible to the posterior surface of the maxilla

▲ Penetrate to about one-half the length of the long needle (16 mm)

▲ Confirm negative aspiration

▲ Slowly inject 1.8 ml of anesthetic solution

▲ Remove the needle along the same path

This technique is consistent with Malamed’s description of the posterior superior alveolar nerve block. The use of a long needle allows better visualization of the angle at which the needle advances.

I personally tabulated 46 attempts at V2 anesthesia using this technique during a four-month period. Of these attempts, 15 (33 percent) resulted in profound anesthesia throughout the quadrant and 30 (65 percent) had sufficient analgesia and needed no further injections or topical anesthetic during root planing.

Of the clients who needed more anesthesia, all required injections at the anterior superior alveolar nerve, two required additional nasopalatine anesthesia, and one required additional greater palatine anesthesia. There were four (8.7 percent) positive aspirations with no hematomas. Two of those with positive aspiration and repositioning of the needle required injections at additional sites.

Interestingly, when performing root planing on maxillary and mandibular quadrants on the same visit and the same side, with one needle penetration site for inferior alveolar and lingual blocks and one needle penetration intended for V2, there were no instances in which the buccal gingiva of the mandibular molars required a separate injection. As the long buccal nerve via the anterior division of the mandibular nerve innervates this area, sufficient anesthetic diffuses to that nerve where it passes by the lateral pterygoid muscle.

Why does this technique provide sufficient analgesia for root planing in a majority of cases despite the deposition of anesthetic closer to the posterior superior alveolar nerve rather than the maxillary nerve?

I believe there are two explanations. First, the pterygopalatine fossa is a narrow space almost completely enclosed by the sphenoid, palatine, and maxillary bones. The dense periosteum surrounding the fossa is probably more resistant to diffusion of the anesthetic solution than the soft tissue within the fossa. It acts as a funnel, guiding movement of the fluid medially and superiorly toward the maxillary nerve until pressure from the solution has equilibrated with the surrounding tissue.

Second, although the funneling effect does not usually reach the levels of anesthetic needed to achieve profound anesthesia, the anesthetic significantly affects the narrower and unmyelinated nerves involved in pain sensation.

Given the presence of the pterygoid venous plexus in the pterygopalatine fossa, particular care must be used when selecting clients and administering anesthetics for the maxillary nerve block. An inexperienced operator should avoid a V2 block until he or she has successfully administered many posterior superior alveolar nerve blocks.

Additional contraindications to the technique described are a client with a small skull, such as a child, an uncooperative client, inflammation, and the risk of excessive bleeding.

Complications of Local Anesthesia

Anesthetic toxicity (overdose)

While rare in adults, young children are more likely to experience toxic reactions because of their lower weight. Most adverse drug reactions occur within 5-10 minutes of injection. Overdose of local anesthetics are caused by high blood levels of anesthetic as a result of an inadvertent intravascular injection or repeated injections. Local anesthetic overdose results in excitation followed by depression of the central nervous system and to a lesser extent of the cardiovascular system.

Early subjective symptoms of the central nervous system include dizziness, anxiety and confusion and may be followed by diplopia, tinnitus, drowsiness and circumoral numbness or tingling. Objective signs include muscle twitching, tremors, talkativeness, slowed speech and shivering followed by overt seizure activity. Unconsciousness and respiratory arrest may occur.

The initial cardiovascular system response to local anesthetic toxicity is an increase in heart rate and blood pressure. As blood plasma levels of the anesthetic increase, vasodilatation occurs followed by depression of the myocardium with subsequent fall in blood pressure. Bradycardia and cardiac arrest may follow.

Local anesthetic toxicity is preventable by following proper injection technique, i.e., aspiration during slow injection. Clinicians should be knowledgeable of maximum dosages based on weight. If lidocaine topical anesthetic is used it should factored into the total administered dose as it can infiltrate into the vascular system. After injection the patient should be observed for any possible toxic response as early recognition and intervention are the keys to a successful outcome.

Allergic reactions

Although allergic reactions to injectable amide local anesthetics are rare, patients may exhibit a reaction to the bisulfite preservative added to anesthetics containing epinephrine. Patients with a sulfa allergy should not receive articaine. Patients may also exhibit allergic reactions to benzocaine topical anesthetics. Allergies can manifest in a variety of ways including urticaria, dermatitis, angioedema, fever, photosensitivity and anaphylaxis.

Paresthesia

Paresthesia is the persistence of anesthetic symptoms beyond the expected duration. It can be caused by trauma to the nerve by the needle during injection. It can also be caused by hemorrhage in and around the nerve. Reports of paresthesia are more common with articaine and prilocaine and thus nerve block should be avoided in children with these local anesthetics. The tongue and lips are the most common areas affected. Most cases resolve in 8 weeks without treatment.

Postoperative soft tissue injury

Accidental biting or chewing of the lip, tongue or cheek is a problem seen in very young pediatric mentally or physically disabled patients. Soft tissue anesthesia lasts longer than pulpal anesthesia and may be present for up 4 hours after local anesthesia administration. The most common area of trauma is the lower lip and to a lesser extent the tongue, followed by the upper lip.

Several preventive measures can be followed:

Select a local anesthetic with a duration of action that is appropriate for the length of the planned procedure.
Advise the patient and accompanying adult about the possibility of injury if the patient bites, sucks or chews on the lips, tongue and cheek. They should delay eating and avoid hot drinks until the effects of the anesthesia are totally dissipated.
Reinforce the warning with patient stickers and by placing a cotton roll in the mucobuccal fold if anesthesia symptoms persist.
The management of soft tissue trauma involves reassuring the patient and parent (it’s okay if the tissue turns white), allowing up to a week for the injury to heal, and lubricating the area with petroleum jelly or antibiotic ointment to prevent drying, cracking and pain.

In May 2008 the FDA approved OraVerse (Novalar Pharmaceuticals, Inc., San Diego, CA) (phentolamine mesylate) as the first pharmaceutical agent indicated for the reversal of soft tissue anesthesia (anesthesia of the lip and tongue) resulting from an intraoral injection of a local anesthetic containing a vasoconstrictor. Phentolamine mesylate is a non selective, competitive, α-adrenergic antagonist that reverses the effects of extravasation of adrenergic agonists such as epinephrine. A submucosal injection of phentolamine mesylate after an injection of local anesthetic with vasoconstrictor enhances the clearance of the local anesthetic, by increasing blood flow in the injection area and accelerating recovery from soft tissue anesthesia. Studies have shown a 55.6 reduction in median time for return of normal lip sensation and a 60 percent reduction in median time for return of normal tongue sensation. The manufacturer recommends limiting use of OraVerso to patients older than six years.

Conclusion

A clinician’s ability to administer an effective, safe and atraumatic local anesthesia injection to a child (or adult) is a major factor in creating a patient with a life long acceptance of dental treatment. Rather than avoiding local administration for fear of traumatizing the pediatric patient, the clinician should strive to learn and use the latest modalities of local pain control to create a pleasant and comfortable dental experience for the patient.