**Novel Modifications in Administration of Local Anesthetics for Dentoalveolar Surgery**

Esshagh Lassemi, Fina Navi, Mohammad Hosein Kalantar Motamedi, Seyed Mehdi Jafari, Kourosh Taheri Talesh, Kamal Qaranizade and Reza Lasemi

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/59235

**1. Introduction**

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[17] Jorgensen NB, Hayden JJr. Local and Sedation Anesthesia in dentistry. 2 Ed. Lea &

[18] Berns JN, Sadove NS. Mandibular block injection: a method of study using an inject‐

[20] Sicher H, ed. Sicher and DuBrul`s oral amatomy. 5th ed. St. Louis; Ishyaku Euro

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ed radiopaque material. J Am Dent Assoc, 1962 Dec; 65: 735-745.

[19] Madeira MC. Anatomia da Face, 7a ed., São Paulo: Sarvier, 2010.

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America; 1998; 273-280.

Febierg Ed. Philadelphia. 1972: 163p.

54 A Textbook of Advanced Oral and Maxillofacial Surgery Volume 2

Clin North Am. 2012 Jan;56(1):133-48.

The importance of pain management during dental procedures cannot be over-emphasized, but without proper anesthesia, the treatment plan may not be feasible or may result in potential harm to some of the patients. Anesthetic injections should be as painless as possible, especially in the palate which is the most sensitive area of the oral cavity for injection [1].

The conventional nasopalatine nerve block is commonly used to obtain anesthesia in the anterior portion of the palate. The painful nature of this approach, however, has led investi‐ gators to seek alternative methods to obtain an anesthesia. Labial infiltration of the maxillary central incisors can be considered an effective anesthetic substitute for procedures of the anterior palate. This chapter presents the anesthetic effect of a modified labial infiltration method for anesthetizing the nasopalatine nerve. The authors have reported this method of labial infiltration to be an effective alternative to the painful conventional nasopalatine nerve block to obtain efficient anesthesia of the anterior palate (p <0.001).

## **1.1. Modified labial infiltration method to obviate nasopalatine nerve block or lessen pain of injection**

### *1.1.1. Clinical anatomy*

Anesthesia of the nasopalatine nerve is a mandatory prerequisite to perform surgical proce‐ dures on the soft and hard tissues of the anterior palate and for extraction of upper anterior

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teeth [1].The nasopalatine nerve passes through the Incisive fossa which is posteroinferior to anterior nasal spine and finally enters the oral cavity via the incisive foramen and innervates the anterior palate, maxillary central incisors and nasal floor (Figure 1). [1-3]

**Figure 1.** Diagram of the nasopalatine and surrounding nerves

Labial tissues are anaesthetized by labial infiltration. Obtaining anesthesia for the relevant palatal soft tissue is however, not possible this way and necessitates direct injection of an anesthetic agent in the palatal area (incisive papilla). Palatal soft tissues, especially in the vicinity of the hard palate, are tightly attached to the underlying bone. Injection in this area is thus, painful when the conventional method for injecting the anesthetic agent directly into or aside the incisive papilla is used [4].Therefore removal of maxillary teeth without a palatal injection is desirable.

#### **1.2. Technique**

In this technique two injections at two sites should be done.


Novel Modifications in Administration of Local Anesthetics for Dentoalveolar Surgery http://dx.doi.org/10.5772/59235 57

**Figure 2.** Diagram of the nasopalatine and surrounding nerves (from Gray's Anatomy, 37th Ed.).

**Figure 3.** Nerve block (from Malamed 2013, 5th ed.)

teeth [1].The nasopalatine nerve passes through the Incisive fossa which is posteroinferior to anterior nasal spine and finally enters the oral cavity via the incisive foramen and innervates

Labial tissues are anaesthetized by labial infiltration. Obtaining anesthesia for the relevant palatal soft tissue is however, not possible this way and necessitates direct injection of an anesthetic agent in the palatal area (incisive papilla). Palatal soft tissues, especially in the vicinity of the hard palate, are tightly attached to the underlying bone. Injection in this area is thus, painful when the conventional method for injecting the anesthetic agent directly into or aside the incisive papilla is used [4].Therefore removal of maxillary teeth without a palatal

**1.** Anesthesia of the maxillary hard and soft tissue of the labial area is obtained by injection of 1 cc of local anesthetic agent in the labial vestibule, with the syringe parallel to the long axis of the lateral incisor tooth and the needle bevel toward the bone. This is a nerve block because local anesthetic is deposited close to the main nerve trunk [2] (Figures 2, 3 and 4).With this injection the canine, lateral incisor, central incisors, hard and soft tissue of the

**2.** After 2-3 minutes and relative anesthesia of the labial area, infiltration of about 0.6 ml of the remaining solution is administered via a needle inserted superior to the apices of central incisors in the vicinity of the superior border of the base of the anterior nasal spine near the nasal floor at a 45 degree angle to the long axis of the central incisor, to obtain

the anterior palate, maxillary central incisors and nasal floor (Figure 1). [1-3]

**Figure 1.** Diagram of the nasopalatine and surrounding nerves

56 A Textbook of Advanced Oral and Maxillofacial Surgery Volume 2

In this technique two injections at two sites should be done.

alveolar area to the midline are anesthetized.

anesthesia in the anterior palate (Figure 5).

injection is desirable.

**1.2. Technique**

Five to six minutes following the second injection, the extension and efficiency of anesthesia in the anterior palate is assessed by an explorer or periosteal elevator and if pain-free the nasopalatine nerve need not be injected from the palate and there is no need for another injection for extraction or dentoalveolar surgery. In the case of mild pain, severe pain, moderate pain or no anesthesia, a complementary injection in the palate is needed. The authors assessed this via a clinical trial that included 60 patients referring for the extraction of maxillary incisors and canine. They showed complete anesthesia of the anterior area of the palate in 76.7% of patients using this method; 23.3% needed a conventional nasopalatine nerve block to comple‐ ment the effect of anesthesia prior to treatment. In controls we used the conventional technique.

**Figure 4.** The anesthesia of the maxillary hard and soft tissue of the labial area is obtained by injection of 1 cc of local anesthetic agent, with the syringe parallel to the long axis of the tooth. Orient the needle bevel toward the bone.

**Figure 5.** Needle inserted superior to the apices of central incisors in the vicinity of the superior border of the base of the anterior nasal spine near the nasal floor at a 45 degree angle to the long axis of the central incisor, to obtain anes‐ thesia in the anterior palate.

The level of anesthesia obtained by our method in the anterior palate is satisfactory. The labial infiltration method resulted in total anesthesia in the majority of the cases. Failures may be the result of anatomic and physiologic variations. An eight minute wait or longer may be more effective than five minutes following the second injection. The amount of pain experienced by the patients during the injection in the labial infiltration approach is less than the conventional approach in most cases. [5]
