Anatomical prerequisites and formation of the dental plexus
To understand the principles of anesthesia, one must clearly visualize the course of the infraorbital nerve. Its path begins in the infraorbital groove, after which the nerve trunk enters the infraorbital canal and ultimately exits through the infraorbital foramen.
Within the canal itself, important structures branch off from the main trunk—the middle and anterior superior alveolar branches (designated in anatomical nomenclature as rr. alveolares superiores medius et anterior). These branches do not function in isolation. They anastomose with the posterior superior alveolar nerves, thereby forming a unified network—the superior dental plexus, which provides innervation to the dentoalveolar segment.
Features of diffusion in maxillary tissues
The morphology of the maxilla plays a decisive role in choosing the local anesthetic delivery method. The main characteristic of this bone is its porous structure. This spongy architecture creates ideal conditions for local anesthetic solutions to easily and unimpeded penetrate (diffuse) into the deep layers of the bone tissue.
Precisely because of this high bone permeability, infiltration has become the most popular approach in the maxilla. The clinician injects the drug submucosally, placing it above the periosteum strictly in the projection of the root apex of the tooth to be anesthetized.
However, there is a strict exception to this rule. The zygomaticoalveolar crest is located in the region of the first molar. This local area is characterized by a significant increase in bone density, turning it into a zone of reduced diffusion. Administering an anesthetic in this area via infiltration is extremely difficult due to the physical barrier of dense bone tissue.
Classification of main anesthesia methods
Based on plexus anatomy and bone density, several basic local anesthesia techniques for the maxilla are distinguished in oral surgery:
- Tuberal anesthesia. The historical name comes from the Latin term tuber, meaning "tuberosity". The essence of the technique is placing the anesthetic solution directly at the maxillary tuberosity. This allows for a reliable blockade of the posterior superior alveolar nerves.
- Palatal anesthesia. The term is derived from the Latin word palatum (palate). This technique is designed to anesthetize the greater palatine nerve.
- Infraorbital anesthesia. Used for targeted blockade of the middle and anterior superior alveolar branches.
- Incisive anesthesia. Also known as nasopalatine nerve block, used to anesthetize the anterior palate.
- Infiltration anesthesia. A universal method utilizing the diffuse properties of the jaw.
Specifics of infiltration anesthesia
The infiltration approach, being the most common, is conceptually divided into two variants depending on the ultimate goal of solution delivery:
- Direct anesthesia. The drug is injected directly into the tissues that will undergo surgery.
- Indirect anesthesia (dental plexus block). The clinician creates a drug depot at a certain distance from the final target. From this created reservoir, the drug spontaneously diffuses into deeper tissues where the surgical intervention is planned.
Briefly: answers to topical questions
What is the anesthesia zone for tuberal anesthesia?
The anesthesia zone for tuberal anesthesia includes the upper molars and adjacent tissues. This area encompasses:
- Teeth — the first, second, and third maxillary permanent molars.
- Alveolar process tissues — the periosteum and overlying mucosa in the region of the upper molars on the vestibular side.
- Maxillary sinus — the mucosa and bone tissue of its posterolateral wall.
The posterior boundary of the zone is constant, while the anterior boundary is variable: it may pass through the middle of the first molar's crown or reach the middle of the first premolar and the corresponding area of the gingival mucosa.
What is the innervation zone of the greater palatine nerve?
The innervation zone of the greater palatine nerve includes:
- Hard palate — the mucosa of the posterior and middle sections, anteriorly up to the canine.
- Gingiva — on the palatal side.
- Soft palate — partially.
- Minor salivary glands.
What anatomical landmarks are used for needle insertion in tuberal anesthesia?
Landmarks in the region of the upper molars and the zygomaticoalveolar crest are used for needle insertion in tuberal anesthesia.
- Insertion point — the mucosa at the level of the second upper molar (or between the second and third molars), 0.5 cm lateral to the mucobuccal fold.
- Target foramina — located 18–25 mm above the alveolar margin of the upper third molar (corresponding to the middle of its crown).
- Landmark in the absence of molars — insertion is performed posterior to the zygomaticoalveolar crest, which anatomically corresponds to the middle of the missing second molar's crown.
What complications are specific to tuberal anesthesia?
Specific complications of tuberal anesthesia are related to the complex anatomy of the maxillary tuberosity region. They include:
- Extensive hematoma formation — occurs due to needle puncture of the pterygoid venous plexus or injury to blood vessels.
- Intravascular injection — accidental entry of anesthetic with a vasoconstrictor into the bloodstream, provoking cardiovascular and respiratory disturbances.
- Vascular and nerve trauma — caused by a "shaving" action when the needle tip slides along the bone.
- Complications due to incorrect needle depth — reaching the optic nerve (temporary blindness), orbital fat (temporary diplopia), or the lateral pterygoid muscle (pain and restricted mandibular mobility).
The terminology directly indicates the injection site: tuberal — from Lat. tuber (tuberosity), palatal — from Lat. palatum (palate).
Class and exam questions
What elements form the superior dental plexus?
It is formed by the union of the middle and anterior superior alveolar branches (originating from the infraorbital nerve within its canal) with the posterior superior alveolar nerves.
Why is infiltration the primary method of anesthesia in the maxilla?
The maxilla has a pronounced porous structure. This allows the anesthetic solution injected submucosally over the periosteum to easily penetrate deep into the bone toward the root apices.
Where in the maxilla might infiltration fail and why?
In the area of the zygomaticoalveolar crest, which is localized in the region of the first molar. In this area, the bone is very dense, which sharply reduces the diffusion capacity of the solution.
What is the difference between direct and indirect infiltration anesthesia?
Direct anesthesia involves injecting the solution precisely into the future surgery zone, while indirect anesthesia involves creating a drug depot from which it diffuses into deeper tissues where the intervention will be performed.
What else to study on this topic
- Topography of the infraorbital groove and infraorbital foramen
- Anatomical landmarks of the maxillary tuberosity for tuberal block
- Projection of the zygomaticoalveolar crest relative to the roots of the first molar
- Technique for performing incisive (nasopalatine) anesthesia
- Anatomical features of the greater palatine nerve location
Master the entire topic in the course "Surgical Dentistry"
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Tuberal and palatal anesthesia" and 866 more pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 28 video lessons on the subject
Other topics in "Chapter 4. Anesthesia in Oral Surgery (S.A. Rabinovich, S.T. Sokhov)"
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.