Classification of maxillar anesthesia
All local anesthesia methods in the maxilla are divided into two groups: infiltration anesthesia and conduction anesthesia. Each method is typically characterized by five criteria: the blocked nerve, target landmark, anesthetic volume, injection site and direction, and anesthesia zone. This response structure is considered standard in examinations for therapeutic dentistry, oral and maxillofacial surgery.
It is important to remember a terminological nuance: in the maxilla, it is called the alveolar process, whereas in the mandible, it is the alveolar part. The correct term is "anesthesia" rather than "freezing" or "numbing" in the colloquial sense.
Infiltration anesthesia
The most frequently used method in general dental practice. It blocks the terminal branches of the second division of the trigeminal nerve (maxillary nerve). The target landmark is the submucosa, loose connective tissue through which the terminal branches run.
- Anesthetic volume: approximately 0.7 mL (about half of a 1.7–1.8 mL carpule).
- The needle is short (about 21 mm), positioned at a 45° angle to the bone, with the bevel facing the bone.
- Needle insertion depth: 1–3 mm.
- Injection site: from the vestibule — into the transitional fold; from the palatal side — at the border of the alveolar and palatal processes, where there is more loose connective tissue.
Anesthesia zone: the tooth corresponding to the injection site projection, adjacent teeth in the presence of anastomoses, as well as the mucosa and periosteum of the alveolar process in this area.
Tuberous anesthesia
A conduction block that anesthetizes the posterior superior alveolar branches of the maxillary nerve. The target landmark is the foramina on the maxillary tuberosity through which these branches enter. Anesthetic volume is 1.5–2 mL; nowadays, a single carpule is sufficient.
Intraoral approach
- The patient's mouth is opened slightly; the cheek is retracted to the maximum using a mirror or spatula.
- Injection point — 0.5 cm below the transitional fold at the level of the second molar or slightly posterior to it.
- Needle at a 45° angle; the direction of advancement is upward, backward, and inward to a depth of about 2.5 cm.
Extraoral approach according to Egorov
Place the index finger on the outer margin of the orbit and the thumb on the anteroinferior angle of the zygomatic bone. Measure the midpoint of this distance with a ruler. The injection is performed in the skin beneath the lower angle of the zygomatic bone at a 45° angle to the midsagittal plane and 90° to the Frankfort horizontal plane; the direction of needle advancement is similar to the intraoral approach.
Anesthesia zone: first, second, and third molars, as well as the periosteum and mucosa of the alveolar process on the buccal side.
Infraorbital anesthesia
Blocks the anterior and middle superior alveolar branches, as well as the peripheral branches of the infraorbital nerve — the pes anserinus minor. The target landmark is the region of the infraorbital foramen. Modern anesthetics allow avoiding entry into the canal, which prevents injury to the neurovascular bundle.
Locating the projection of the infraorbital foramen
- Palpate the bony prominence — the junction of the zygomatic process of the maxilla with the zygomatic bone; the projection of the foramen is located 0.5 cm inferiorly.
- Draw a vertical line downward through the pupil while looking straight ahead; measure 5 mm inferiorly from the point where it intersects the infraorbital margin.
- A vertical line passing through the second premolar; intersect with the infraorbital margin minus 0.5–0.7 cm inferiorly.
Technique
- Intraoral approach: injection 0.5 cm above the transitional fold in the area of the lateral maxillary incisor.
- Extraoral approach: injection into the skin 1 cm inferior and medial to the projection of the infraorbital foramen, advancing in contact with the bone.
- The operator's finger protects the foramen projection, preventing the needle from entering the canal.
Anesthesia zone: incisors, canine, first and occasionally second premolar; periosteum and mucosa of the alveolar process on the buccal side; skin of the infraorbital region, nasal ala, and upper lip on the corresponding side.
Palatine anesthesia
Performed exclusively via the intraoral approach. Blocks the greater palatine nerve; the target landmark is the greater palatine foramen. Anesthetic volume is only 0.3 mL: an excess leads to mucosal detachment, vascular compression, and necrosis of the hard palate mucosa.
The projection of the greater palatine foramen is determined by the intersection of two mutually perpendicular lines: a horizontal line at the level of the middle of the second molar or between the second and third molars (extending only to the median palatine suture, as the maxilla is a paired bone), and a vertical line through the middle of the canine. Measure 1 cm anteriorly and medially from the intersection point — this is the injection site.
Anesthesia zone: mucosa of the hard palate and alveolar process from the palatal side, extending from the third molar to the middle of the canine. The injection is painful; the patient should be instructed to breathe through the nose and keep their eyes open.
Incisive anesthesia
Blocks the nasopalatine nerve; the target landmark is the incisive foramen region. Anesthetic volume is about 0.2 mL.
- Intraoral approach: injection at the base of the incisive papilla; the patient tilts their head back as far as possible and opens their mouth wide.
- Intranasal (extraoral) approach: injection at the base of the nasal septum, offset by about 1 cm; carries a high risk of epistaxis, and is therefore used less frequently.
Anesthesia zone: hard palate mucosa within the triangular area from canine to canine. Combined with palatine anesthesia, it provides complete anesthesia of the palatal surface.
Key points
- Maxillary anesthesia is divided into infiltration and conduction blocks: tuberomaxillary, infraorbital, palatine, and incisive blocks.
- Each anesthesia method is characterized by 5 points: nerve, target landmark, volume, injection site, and anesthesia zone.
- The needle is positioned at a 45° angle to the bone with the bevel facing the bone; 0.7 mL of anesthetic is sufficient for infiltration.
- Tuberosity (tuberomaxillary) block — advancing the needle upward, backward, and inward by 2.5 cm; anesthetizes the three molars from the buccal side.
- During an infraorbital block, the needle does not enter the canal; the foramen projection is determined using three methods.
- Minimal volumes (0.2–0.3 mL) are injected into the palate to prevent mucosal necrosis.
- Incisive anesthesia blocks the nasopalatine nerve and anesthetizes the palate from canine to canine.
- In the maxilla, it is the alveolar process; in the mandible, the alveolar part; correct terminology is mandatory.