Maxillary Injection Techniques PDF

Dr/Heba Elsheikh Maxillary Injection Techniques Nasopalatine Nerve Block Areas Anesthetized Anterior portion of the hard palate (soft and hard tissues) bilaterally from the mesial of the right first premolar to the mesial of the left first premolar....

Dr/Heba Elsheikh Maxillary Injection Techniques Nasopalatine Nerve Block Areas Anesthetized Anterior portion of the hard palate (soft and hard tissues) bilaterally from the mesial of the right first premolar to the mesial of the left first premolar. Indications 1. When palatal soft tissue anesthesia is necessary for restorative treatment on more than two teeth (e.g., subgingival restorations, insertion of matrix bands subgingivally). 2. For pain control during periodontal or oral surgical procedures involving palatal soft and hard tissues. Contraindications 1. Inflammation or infection at the injection site 2. Smaller area of therapy (one or two teeth) Advantages 1 -Minimizes needle penetrations and volume of solution. 2 -Minimal patient discomfort from multiple needle penetrations. Disadvantages 1- Lack of hemostasis 2- Potentially the most traumatic intraoral injection. Approaches: 1- Single penetration. 2- Multiple penetrations. Single-Needle Penetration of the Palate Armamentariums: A 27-gauge short needle is recommended. Area of insertion: Palatal mucosa just lateral to the incisive papilla (located in the midline behind the central incisors); the tissue here is more sensitive than other palatal mucosa. Target area: Incisive foramen, beneath the incisive papilla. Landmarks: Central incisors and incisive papilla Path of insertion: Approach the injection site at a 45-degree angle toward the incisive papilla. Orientation of the bevel: Toward the palatal soft tissues. 1 Dr/Heba Elsheikh Maxillary Injection Techniques Position: Sit at the 9 or 10 o'clock position facing in the same direction as the patient Procedure: (1) Turn the head to the left or right for improved visibility. (2) Apply topical anesthetic for 2 minutes. (3) Apply pressure to the area of the papilla. (4) Note ischemia at the injection site. (5) Place the bevel against the ischemic soft tissues at the injection site. The needle must be well stabilized to prevent accidental penetration of tissues (6) Slowly advance the needle toward the incisive foramen until bone is gently contacted. (7) The depth of penetration normally is not greater than 5 mm. (8) Deposit small volumes of anesthetic while advancing the needle. As the tissue is entered, resistance to the deposition of solution is significantly increased; this is normal with the nasopalatine nerve block (9) Withdraw the needle 1 mm. (10) Aspirate in two planes. (11) If negative, slowly deposit (15- to 30-second minimum) not more than one fourth of a cartridge (0.45 mL). Signs and Symptoms 1 Subjective: numbness in the anterior portion of the palate 2 Objective: no pain during dental therapy. Failures of Anesthesia 1- Inadequate palatal soft tissue anesthesia in the area of the maxillary canine and first premolar: If fibers from the greater palatine nerve overlap those of the nasopalatine nerve, anesthesia of the soft tissues palatal to the canine and the first premolar could be inadequate. To correct: Local infiltration may be necessary as a supplement in the area inadequately anesthetized. Complications 1- Hematoma is possible but extremely rare because of the density and firm adherence of palatal soft tissues to bone. 2- Necrosis of soft tissues is possible when highly concentrated vasoconstricting solution (e.g., norepinephrine) is used for hemostasis over a prolonged period 2 Dr/Heba Elsheikh Maxillary Injection Techniques Multiple Needle Penetrations Areas of insertion: a Labial frenum in the midline between the maxillary central incisors. b Interdental papilla between the maxillary central incisors. c If needed, palatal soft tissues lateral to the incisive papilla. Target area: Incisive foramen, beneath the incisive papilla. Landmarks: Central incisors and incisive papilla. Path of insertion: a) First injection: infiltration into the labial frenum b) Second injection: needle held at a right angle to the interdental papilla c) Third injection: needle held at a 45-degree angle to the incisive papilla Procedure: First injection: infiltration of 0.3 mL into the labial frenum.  Retract the upper lip to stretch tissues and improve visibility.  Gently insert the needle into the frenum and deposit 0.3 mL of anesthetic in approximately 15 seconds. (The tissue may balloon as solution is injected.).  Anesthesia of soft tissue develops immediately.  The aim of this first injection is to anesthetize the interdental papilla between the two central incisors. Second injection: penetration through the labial aspect of the papilla between the maxillary central incisors toward the incisive papilla. Retract the upper lip gently to increase visibility. Holding the needle at a right angle to the interdental papilla, insert it into the papilla just above the level of crestal bone. Direct it toward the incisive papilla (on the palatal side of the interdental papilla). With the patient's head extended backward, you can see the ischemia produced by the local anesthetic and (on occasion) can see the needle tip as it nears the palatal aspect of the incisive papilla. Aspirate in two planes, If negative, administer no more than 0.3 mL of anesthetic solution in approximately 15 seconds. Third injection: Place the needle into soft tissue adjacent to the (diamond-shaped) incisive papilla, aiming toward the most distal portion of the papilla. 3 Dr/Heba Elsheikh Maxillary Injection Techniques Advance the needle until contact is made with bone. Withdraw the needle 1 mm to avoid subperiosteal injection. Aspirate in two planes. If negative, slowly deposit not more than 0.3 mL of anesthetic in approximately 15 seconds. Signs and Symptoms 1 Subjective: numbness of the upper lip (in the midline) and the anterior portion of the palate. 2 Objective: no pain during dental therapy. Advantage Entirely or relatively atraumatic Disadvantages 1 Requires multiple injections (three). 2 Difficult to stabilize the syringe during the second injection. 3 Syringe barrel usually within the patient's line of sight during the second injection. Anterior Middle Superior Alveolar Nerve Block This technique provides pulpal anesthesia to multiple maxillary teeth (incisors, canine, and premolars) from a single injection site on the hard palate about halfway along an imaginary line connecting the midpalatal suture to the free gingival margin. The line is located at the contact point between the first and second premolars. Nerves Anesthetized: 1. ASA nerve. 2. MSA nerve, when present. 3. Subneural dental nerve plexus of the anterior and middle superior alveolar nerves. Areas Anesthetized: 1. Pulpal anesthesia of the maxillary incisors, canines, and premolars. 2. Buccal attached gingiva of these same teeth. 4 Dr/Heba Elsheikh Maxillary Injection Techniques 3. Attached palatal tissues from midline to free gingival margin on associated teeth. Other Common Names: Palatal approach anterior middle superior alveolar (AMSA) Indications: 1 Is more easily performed with a C-CLAD system. 2 When dental procedures involving multiple maxillary anterior teeth or soft tissues are to be performed. 3 When anesthesia to multiple maxillary anterior teeth is desired from a single-site injection. 4 When scaling and root planning of the anterior teeth are to be performed. 5 When anterior cosmetic procedures are to be performed and a smile-line assessment is important for a successful outcome. 6 When a facial approach supraperiosteal injection has been ineffective because of dense cortical bone. Contraindication: 1 Patients with unusually thin palatal tissues. 2 Patients unable to tolerate the 3- to 4-minute administration time. 3 Procedures requiring longer than 90 minutes. Advantages: 1 Provides anesthesia of multiple maxillary teeth with a single injection. 2 Comparatively simple technique. 3 Comparatively safe; minimizes the volume of anesthetic and the number of punctures required compared with traditional maxillary infiltrations of these teeth. 4 Allows effective soft tissue and pulpal anesthesia for periodontal scaling and root planning of associated maxillary teeth. 5 Allows an accurate smile-line assessment to be performed after anesthesia has occurred, which may be helpful during cosmetic dentistry procedures. 6 Eliminates the postoperative inconvenience of numbness to the upper lip and muscles of facial expression. 7 Can be performed comfortably with a C-CLAD system. Disadvantages: 1 Requires a slow administration (0.5 mL/min) time. 2 Can cause operator fatigue with a manual syringe because of extended injection time. 3 May be uncomfortable for the patient if administered improperly. 4 May need supplemental anesthesia for central and lateral incisor teeth. 5 May cause excessive ischemia if administered too rapidly. 5 Dr/Heba Elsheikh Maxillary Injection Techniques 6 Use of local anesthetic containing epinephrine with a concentration of 1:50,000 is contraindicated. Technique Armamentariums:  27-gauge short needle recommended. Area of insertion:  On the hard palate about halfway along an imaginary line connecting the midpalatal suture to the free gingival margin; the location of the line is at the contact point between the first and second premolars. Target area:  Palatal bone at injection site. Landmarks:  The intersecting point midway along a line from the midpalatine suture to the free gingival margin intersecting the contact point between the first and second premolars. Orientation of the bevel:  The bevel of the needle is placed “face down” against the epithelium. The needle is typically held at a 45-degree angle to the palate. Steps: a) Sit at the 9 or 10 o'clock position facing same direction as the patient b) Position the patient supine with slight hyperextension of the head and neck so you can visualize the nasopalatine papilla more easily. c) Use preparatory communication to inform the patient that the injection may take several minutes to administer, and that it may produce a sensation of firm pressure in the palate. d) Use comfortable arm and finger rests to avoid fatigue during the extended administration time. e) Use of a C-CLAD system is suggested because it makes this injection easier to administer. f) Initial orientation of bevel is “face down” toward the epithelium, while the needle is held at approximately a 45-degree angle with a tangent to the palate. g) The final target is the bevel in contact with the palatal bone. 6 Dr/Heba Elsheikh Maxillary Injection Techniques h) A prepuncture technique can be utilized. Apply the bevel of the needle toward the palatal tissue. Place a sterile cotton applicator on top of the needle tip. Apply light pressure on the cotton applicator to create a “seal” of the needle bevel against the outer surface. Initiate delivery of the local anesthetic to the surface of the epithelium. The objective is to force the solution through the outer epithelium into the surface tissue. The cotton applicator provides stabilization of the needle and prevents any excess local anesthetic solution from dripping into the patient's mouth. When a C-CLAD system is used, a slow rate of delivery (approximately 0.5 mL/min) is maintained during the entire injection. Maintain this position and pressure on the surface of the epithelium for 8 to 10 seconds. i) An “anesthetic pathway technique” can be utilized. Very slowly advance the needle tip into the tissue. Rotating the needle allows the needle to penetrate the tissue more efficiently. Advance the needle 1 to 2 mm every 4 to 6 seconds while administering the anesthetic solution at the recommended slow rate. Attempt to not expand the tissue or advance the needle too rapidly if performing this with a manual syringe. Use of a C- CLAD system makes this process considerably easier to perform. j) After initial blanching is observed (approximately 30 seconds), pause for several seconds to allow for onset of superficial anesthesia. k) Continue the slow insertion technique into the palatal tissue. Orientation of the handpiece should be from the contralateral premolars. The needle is advanced until contact with bone occurs. l) Ensure that needle contact is maintained with the bony surface of the palate. The bevel of the needle should face the surface of the bone. m) Aspirate in two planes. n) Anesthetic is delivered at a rate of approximately 0.5 mL per minute during the injection for a total dosage of approximately 1.4 to 1.8 mL. o) Advise the patient that he or she will experience a sensation of firm pressure. Signs and Symptoms Subjective:  A sensation of firmness and numbness is experienced immediately on the palatal tissues.  Numbness of the teeth and associated soft tissues extends from the central incisor to the second premolar on the side of the injection. Objective:  Blanching of the soft tissues (if a vasoconstrictor is used) of the palatal and facial attached gingiva is evident, extending from the central incisor to the premolar region. 7 Dr/Heba Elsheikh Maxillary Injection Techniques  Use of electrical pulp testing with no response from teeth with maximal EPT output (80/80).  Absence of pain during treatment.  No anesthesia of the face and upper lip occurs. Safety Features 1 Contact with bone. 2 Low risk of positive aspiration. 3 Slow insertion of needle (1 to 2 mm every 4 to 6 seconds). 4 Slow administration of local anesthetic (0.5 mL/min). 5 Less anesthetic required than if traditional injections are used. Precautions Against pain:  Extremely slow insertion of needle.  Slow administration during insertion with simultaneous administration of anesthetic solution.  C-CLAD device recommended. Against tissue damage:  Avoid excessive ischemia by avoiding local anesthetics containing vasoconstrictors with a concentration of 1:50,000.  Avoid multiple infiltrations of local anesthetic with vasoconstrictor in the same at a single appointment. Complications 1 Palatal ulcer at injection site developing 1 to 2 days postoperatively  Self-limiting.  Heals in 5 to 10 days.  Prevention includes slow administration to avoid excessive ischemia.  Avoid excessive concentrations of vasoconstrictor (e.g., 1:50,000).  Avoid multiple infiltrations of local anesthetic with vasoconstrictor in the same area at a single appointment. 2 Density of tissues at injection site causing squirt-back of anesthetic and bitter taste:  Aspirate while withdrawing syringe from tissue.  Pause 3 to 4 seconds before withdrawing the needle to allow pressure to dissipate.  Instruct assistant to suction any excess anesthetic that escapes during administration. 8 Dr/Heba Elsheikh Maxillary Injection Techniques Palatal Approach-Anterior Superior Alveolar The P-ASA injection shares several common elements with the nasopalatine nerve block but differs sufficiently to be considered a distinct identity. The P-ASA uses a similar tissue point of entry (lateral aspect of the incisive papilla) as the nasopalatine but differs in its final target, that is, the needle positioned within the incisive canal. The volume of anesthetic recommended for the P-ASA is 1.4 to 1.8 mL, administered at a rate of 0.5 mL per minute. Nerves Anesthetized: 1 Nasopalatine 2 Anterior branches of the ASA. Areas Anesthetized: 1 Pulps of the maxillary central incisors, the lateral incisors, and (to a lesser degree) the canines. 2 Facial periodontal tissue associated with these same teeth. 3 Palatal periodontal tissue associated with these same teeth. Indications: 1 When dental procedures involving the maxillary anterior teeth and soft tissues are to be performed. 2 When bilateral anesthesia of the maxillary anterior teeth is desired from a single site injection. 3 When scaling and root planning of the anterior teeth are to be performed. 4 When anterior cosmetic procedures are to be performed and a smile-line assessment is important to a successful outcome. 5 When a facial approach supraperiosteal injection has been ineffective because of dense cortical bone. Contraindication: 1 Patients with extremely long canine roots may not achieve profound anesthesia of these teeth from a palatal approach alone. 2 Patients who cannot tolerate the 3- to 4-minute administration time. 3 Procedures requiring longer than 90 minutes. Advantages: 1. Provides bilateral maxillary anesthesia from a single injection site. 2. Comparatively simple technique. 3. Comparatively safe; minimizes the volume of anesthetic and the number of punctures required compared with traditional maxillary infiltrations of these teeth. 4. Allows an accurate smile-line assessment to be performed after anesthesia has occurred, which may be helpful during cosmetic dentistry procedures. 9 Dr/Heba Elsheikh Maxillary Injection Techniques 5. Eliminates the postoperative inconvenience of numbness to the upper lip and muscles of facial expression. 6. Can be performed comfortably with a C-CLAD system. Disadvantages: 1. Requires a slow administration (0.5 mL/min) time. 2. Can cause operator fatigue with a manual syringe because of extended injection time. 3. May be uncomfortable for the patient if administered improperly. 4. May need supplemental anesthesia for canine teeth. 5. May cause excessive ischemia if administered too rapidly. 6. Use of local anesthetic containing epinephrine with a concentration of 1:50,000 is contraindicated. Technique Armamentariums:  27-gauge short needle recommended. Area of insertion:  Just lateral to the incisive papilla in the papillary groove Target area:  Nasopalatine foramen. Landmarks:  Nasopalatine papilla. Orientation of the bevel:  The bevel of the needle is placed “face down” against the epithelium. The needle is typically held at a 45-degree angle to the palate. Steps: a) Sit at the 9 or 10 o'clock position facing same direction as the patient b) Position the patient supine with slight hyperextension of the head and neck so you can visualize the nasopalatine papilla more easily. c) Use preparatory communication to inform the patient that the injection may take several minutes to administer, and that it may produce a sensation of firm pressure in the palate. d) Use comfortable arm and finger rests to avoid fatigue during the extended administration time. 10 Dr/Heba Elsheikh Maxillary Injection Techniques e) Use of a C-CLAD system is suggested because it makes this injection easier to administer. f) Initial orientation of bevel is “face down” toward the epithelium, while the needle is held at approximately a 45-degree angle with a tangent to the palate. g) A prepuncture technique can be utilized. Apply the bevel of the needle toward the palatal tissue. Place a sterile cotton applicator on top of the needle tip. Apply light pressure on the cotton applicator to create a “seal” of the needle bevel against the outer surface. Initiate delivery of the local anesthetic to the surface of the epithelium. The objective is to force the solution through the outer epithelium into the surface tissue. The cotton applicator provides stabilization of the needle and prevents any excess local anesthetic solution from dripping into the patient's mouth. When a C- CLAD system is used, a slow rate of delivery (approximately 0.5 mL/min) is maintained during the entire injection. Maintain this position and pressure on the surface of the epithelium for 8 to 10 seconds. h) An “anesthetic pathway technique” can be utilized. Very slowly advance the needle tip into the tissue. Rotating the needle allows the needle to penetrate the tissue more efficiently. Advance the needle 1 to 2 mm every 4 to 6 seconds while administering the anesthetic solution at the recommended slow rate. Attempt to not expand the tissue or advance the needle too rapidly if performing this with a manual syringe. Use of a C-CLAD system makes this process considerably easier to perform. i) After initial blanching is observed (approximately 30 seconds), pause for several seconds to allow for onset of superficial anesthesia. j) Continue the slow insertion technique into the nasopalatine canal. Orientation of the needle should be parallel to the long axis of the central incisors. The needle is advanced to a depth of 6 to 10 mm. Note: If resistance is encountered before the final depth of penetration is reached, do not force the needle forward. Withdraw it slightly and reorient it to minimize the risk of penetration of the floor of the nose. k) Ensure that the needle is in contact with the inner bony wall of the canal. (A well- defined nasopalatine canal may not be present in some patients.). l) Aspirate in two planes within the canal space to avoid intravascular injection. m) Anesthetic is delivered at a rate of approximately 0.5 mL during the injection to a total volume of 1.4 to 1.8 mL. Advise the patient that he or she will experience a sensation of firm pressure. 11 Dr/Heba Elsheikh Maxillary Injection Techniques Signs and Symptoms Subjective:  A sensation of firmness and numbness is experienced immediately in the anterior palate.  Numbness of the teeth and associated soft tissues extends from the right to the left canine. Objective:  Blanching of the soft tissues (if a vasoconstrictor is used) of the palatal and facial attached gingiva is evident, extending from the right to the left canine region.  Use of electrical pulp testing with no response from teeth with maximal EPT output (80/80).  Absence of pain during treatment.  No anesthesia of the face and upper lip occurs. Safety Features 1 Contact with bone. 2 Low risk of positive aspiration. 3 Slow insertion of needle (1 to 2 mm every 4 to 6 seconds). 4 Slow administration of local anesthetic (0.5 mL/min). 5 Less anesthetic required than if traditional injections are used. 6 Precautions Against pain:  Extremely slow insertion of needle.  Slow administration during insertion with simultaneous administration of anesthetic solution.  C-CLAD device recommended. Against tissue damage:  Avoid excessive ischemia by avoiding local anesthetics containing vasoconstrictors with a concentration of 1:50,000.  Avoid multiple infiltrations of local anesthetic with vasoconstrictor in the same at a single appointment. Complications 1 Palatal ulcer at injection site developing 1 to 2 days postoperatively  Self-limiting.  Heals in 5 to 10 days. 12 Dr/Heba Elsheikh Maxillary Injection Techniques  Prevention includes slow administration to avoid excessive ischemia.  Avoid excessive concentrations of vasoconstrictor (e.g., 1:50,000).  Avoid multiple infiltrations of local anesthetic with vasoconstrictor in the same area at a single appointment. 2 Unexpected contact with the nasopalatine nerve. 3 Density of tissues at injection site causing squirt-back of anesthetic and bitter taste:  Aspirate while withdrawing syringe from tissue.  Pause 3 to 4 seconds before withdrawing the needle to allow pressure to dissipate.  Instruct assistant to suction any excess anesthetic that escapes during administration. Maxillary Nerve Block Other Common Names Second division block, V2 nerve block. Areas Anesthetized 1. Pulpal anesthesia of the maxillary teeth on the side of the block. 2. Buccal periodontium and bone overlying these teeth. 3. Soft tissues and bone of the hard palate and part of the soft palate, medial to midline. 4. Skin of the lower eyelid, side of the nose, cheek, and upper lip. Indications 1- Pain control before extensive oral surgical, periodontal, or restorative procedures requiring anesthesia of the entire maxillary division. 2- When tissue inflammation or infection precludes the use of other regional nerve blocks (e.g., PSA, ASA, AMSA, P-ASA) or supraperiosteal injection. 3- Diagnostic or therapeutic procedures for neuralgias or tics of the second division of the trigeminal nerve. Contraindications 1- Inexpert administrator. 2- Pediatric patients. 3- Uncooperative patients. 4- Inflammation or infection of tissues overlying the injection site. 5- When hemorrhage is risky (e.g., in a hemophiliac). Advantages 1- High success rate (>95%). 2- Positive aspiration is less than 1% (greater palatine canal approach). 3- Minimizes the number of needle penetrations. 4- Minimizes total volume of local anesthetic solution injected. 13 Dr/Heba Elsheikh Maxillary Injection Techniques Disadvantages 1- Risk of hematoma, primarily with the high-tuberosity approach. 2- High-tuberosity approach is relatively arbitrary. Overinsertion is possible because of the absence of bony landmarks if proper technique is not followed. 3- Lack of hemostasis: If necessary, this necessitates infiltration with vasoconstrictor-containing local anesthetic at the surgical site. 4 -Pain: The greater palatine canal approach is potentially (although not usually) traumatic. Approaches: High tuberosity approach. Greater palatine canal approach. High-Tuberosity Approach Armamentariums: A 25-gauge long needle is recommended. A 27-gauge long is acceptable. Area of insertion: Height of the mucobuccal fold above the distal aspect of the maxillary second molar. Target area: Maxillary nerve as it passes through the pterygopalatine fossa, superior and medial to the target area of the PSA nerve block Landmarks: a Mucobuccal fold at the distal aspect of the maxillary second molar. b Maxillary tuberosity. c Zygomatic process of the maxilla. Orientation of the bevel: toward bone. Position: 1) For a left high-tuberosity injection, a right-handed administrator should sit at the 10 o'clock position facing the patient. (2) For a right high-tuberosity injection, a right-handed administrator should sit at the 8 o'clock position facing the patient. Procedure: 1- Measure the length of a long needle from the tip to the hub (average, 32 mm, but varies by manufacturer). 2- Prepare the tissue in the height of the mucobuccal fold at the distal of the maxillary second molar. Dry with sterile gauze. Apply topical antiseptic (optional). 14 Dr/Heba Elsheikh Maxillary Injection Techniques Apply topical anesthetic. 3- Partially open the patient's mouth; pull the mandible toward the side of injection. 4- Retract the cheek in the injection area with your index finger to increase visibility. 5- Pull the tissues taut with this finger. 6- Place the needle into the height of the mucobuccal fold over the maxillary second molar. 7- Advance the needle slowly in an upward, inward, and backward direction as described for the PSA nerve block 8- Advance the needle to a depth of 30 mm. No resistance to needle penetration should be felt. If resistance is felt, the angle of the needle in toward the midline is too great. 9- At this depth (30 mm), the needle tip should lie in the pterygopalatine fossa in proximity to the maxillary division of the trigeminal nerve. 10- Aspirate in two planes. If negative: Slowly (more than 60 seconds) deposit 1.8 mL. 11- Aspirate several times during injection. Greater Palatine Canal Approach Armamentariums: A 25-gauge long needle is recommended. A 27-gauge long needle is also acceptable. Area of insertion: Palatal soft tissue directly over the greater palatine foramen. Target area: The maxillary nerve as it passes through the pterygopalatine fossa; the needle passes through the greater palatine canal to reach the pterygopalatine fossa. Landmark: Greater palatine foramen, junction of the maxillary alveolar process and the palatine bone. Orientation of the bevel: toward palatal soft tissues. Position: (1) For a right greater palatine canal V2 block, sit facing toward the patient at the 7 or 8 o'clock position. (2) For a left greater palatine canal V2 block, sit facing in the same direction as the patient at the 10 or 11 o'clock position. Procedure: 1- Measure the length of a long needle from the tip to the hub (average, 32 mm, but varies by manufacturer). 2- Ask the patient, who is supine, to do the following: Open wide. Extend the neck. 15 Dr/Heba Elsheikh Maxillary Injection Techniques Turn the head to the left or right (to improve visibility). 3- Locate the greater palatine foramen.  Place a cotton swab at the junction of the maxillary alveolar process and the hard palate.  Start in the region of the second molar and palpate by pressing posteriorly into the tissues with the swab.  The swab “falls” into the depression created by the greater palatine foramen.  The foramen is most frequently located at the distal aspect of the maxillary second molar. Apply pressure to the tissue with the cotton swab, held in the left hand (if right-handed).  Note ischemia at the injection site. 4- Direct the syringe into the mouth from the opposite side with the needle approaching the injection site at a right angle 5- Place the bevel against the ischemic soft tissue at the injection site and deposit a small volume of local anesthetic. The solution is forced against the mucous membrane, forming a droplet. 6- Continue to deposit small volumes of anesthetic throughout the procedure. 7- Continue to apply pressure with the cotton applicator stick during this part of the procedure. The greater palatine nerve block is now complete. 8- Probe gently for the greater palatine foramen. The patient feels no discomfort because of the previously deposited anesthetic solution. The angle of the needle and syringe may be changed if needed. The needle usually must be held at a 45-degree angle to facilitate entry into the greater palatine foramen. 9- After locating the foramen, very slowly advance the needle into the greater palatine canal to a depth of 30 mm. Approximately 5% to 15% of greater palatine canals have bony obstructions that prevent passage of the needle. Never attempt to force the needle against resistance. If resistance is felt, withdraw the needle slightly and slowly attempt to advance it at a different angle. If the needle cannot be advanced farther and the depth of penetration is almost adequate, continue with the next steps; however, if the depth is considerably deficient, withdraw the needle and discontinue the attempt. 10- Aspirate in two planes. 11- If negative, slowly deposit 1.8 mL of solution over a minimum of 1 minute. 16 Dr/Heba Elsheikh Maxillary Injection Techniques Signs and Symptoms Subjective: Pressure behind the upper jaw on the side being injected; this usually subsides rapidly, progressing to tingling and numbness of the lower eyelid, side of the nose, and upper lip Sensation of numbness in the teeth and buccal and palatal soft tissues on the side of injection. Objective: Use of electrical pulp testing with no response from teeth with maximal EPT output (80/80) Absence of pain during treatment. Failures of Anesthesia 1- Partial anesthesia; may result from underpenetration by needle. To correct: Reinsert the needle to proper depth, and reinject. 2- Inability to negotiate the greater palatine canal. To correct: Withdraw the needle slightly and reangulate it. Reinsert carefully to the proper depth. If unable to bypass the obstruction easily, withdraw the needle and terminate the injection. The high-tuberosity approach may prove more successful in this situation. N.B : The greater palatine canal approach usually is successful if the long dental needle has been advanced at least two thirds of its length into the canal. Complications 1- Hematoma develops rapidly if the maxillary artery is punctured during maxillary nerve block via the high-tuberosity approach. 2- Penetration of the orbit may occur during a greater palatine foramen approach if the needle goes in too far. 3- Complications produced by injection of local anesthetic into the orbit include the following: a) Volume displacement of the orbital structures, producing periorbital swelling and proptosis. 17 Dr/Heba Elsheikh Maxillary Injection Techniques b)Diplopia. c)Possible optic nerve block with transient loss of vision. d)Possible retrobulbar hemorrhage. 4-Penetration of the nasal cavity: If the needle deviates medially during insertion through the greater palatine canal, the paper-thin medial wall of the pterygopalatine fossa is penetrated and the needle enters the nasal cavity. On aspiration, large amounts of air appear in the cartridge. On injection, the patient complains that local anesthetic solution is running down his or her throat. To prevent: Keep the patient's mouth wide open and take care during penetration that the advancing needle stays in the correct plane and do not force needle if resistance is encountered. 18