**6. Factors influence the efficiency of local anesthesia**

#### **6.1 Anesthetic agent**

Contrary to popular belief, most moderate-duration anesthetics are equally efficient in inducing deep pulpal anesthetic for root canal treatment. Understanding the anatomical, local, and psychological aspects of each patient against the type of anesthetic utilized is critical to success. Most dentists prefer to employ a combination of anesthetics and a vasoconstrictor. When some types of anesthetic drugs are used, it is possible that the patients would experience more pain. Because of the acidic nature of local anesthetics, lower pH values are considered to produce a burning sensation during injection [23].

#### **6.2 Site of injection**

The injection location might influence injection discomfort. According to one study, maxillary buccal injections with plain 2% lidocaine Was found to be considerably less discomfort than 2% lidocaine with 1:80000 epinephrine. However, using the same anesthetic drugs, no difference in injection discomfort was recorded at the palatal location [12]. The type of anesthetic solution has little effect on injection discomfort when a location with less connective tissue (such as the palatal site in the maxilla) is injected. Faster injection speed leads to increased drug distribution. It has been proposed that a speed of injection exposes a larger portion of a nerve to the anesthetic solution, resulting in a higher rate of local anesthesia success. The rapid injections, on the other hand, produced more pain and discomfort during the procedure [23–25].

#### **6.3 Preoperative pain**

In individuals with symptomatic irreversible pulpitis, the degree of preoperative pain might impact anesthetic success. The activation of nociceptors during inflammation might be one reason for the lower success rate of inflamed pulp. The peripheral and central pain pathways are altered and modulated by the barrage of painful stimuli, as well as tissue destruction. Another reason for failure is that nerves from inflamed tissue have reduced excitability thresholds and altered resting potentials [26].

#### **6.4 Pre emptive medication**

Inflamed pulps may have more tetrodotoxin-resistant sodium channels, which are resistant to local anesthetics. Prostaglandins, which can influence tetrodotoxinresistant receptors and reduce nerve responses to anesthetic drugs, have also risen considerably in inflamed pulps [27]. As a result, premedication with nonsteroidal anti-inflammatory medicines (NSAIDs) and corticosteroids to increase anesthetic success appear to be a viable option. However, the findings of such research do not agree on the effectiveness of premedication on anesthetic success [28, 29]. However, if the patient does not have spontaneous pain, pre-treatment with

#### *Topics in Regional Anesthesia*

particular types of NSAIDs may improve the effectiveness of anesthesia when treating irreversible pulpitis [30]. Premedication with corticosteroids before anesthesia with an inferior alveolar nerve block (IANB) injection resulted in a considerably better success rate.

#### **6.5 Gender and genetic factor**

Genetics may play a role in predisposing specific individuals to problems such as discomfort, delayed healing, and abscess development. A range of genetic variations influences pain perception and behavior. Pain becomes significantly more common in women, and various explanations have been proposed, including hormonal and genetically driven sex variations in brain neurochemistry [27].
