Paresthesia in dentistry: The ignored neurotoxicity of local anesthetics

Schwann cells exposed to articaine display distinct toxic pathways compared to lidocaine

Articaine (ATC) has emerged as one of the most popular local anesthetics (LA) in dental clinics, despite its relatively recent introduction to the market. As a member of the amino-amide class of LA, ATC possesses unique features, including a thiophene ring and an ester group, which allow for its use at higher clinical concentrations. However, reports have indicated a higher incidence of paresthesia associated with ATC, though the underlying cause of this effect remains unclear. To investigate this further, we conducted an extracellular metabolic flux analysis and an NMR-based metabolomics study of ATC effects on Schwann cells - a type of glial cell found in the peripheral nervous system - in comparison to lidocaine (LDC), the "gold standard" LA in dentistry. The results showed that ATC had a more significant impact on Schwann cell oxygen consumption compared to LDC. Metabolomics profiling of Schwann cells revealed distinct metabolic alterations between the two treatments. Notably, ATC triggered elevated intracellular levels of various amino acids, including leucine, isoleucine, valine, phenylalanine, methionine, histidine, tyrosine, and glycine, which were not observed in LDC-treated Schwann cells. This was consistent with signs of endoplasmic reticulum stress and apoptosis in ATC-treated cells, as detected by protein expression analysis. These findings offer insights into the metabolic and cellular responses elicited by the two anesthetics in Schwann cells, that may help explain the differential toxicity and higher incidence of paresthesia associated with ATC.

Adjunctive Effect of Photobiomodulation Therapy with Nd:YAG Laser in the Treatment of Inferior Alveolar Nerve Paresthesia

Background: Disruption of peripheral branches of the trigeminal nerve in the field of maxillofacial surgery is a known risk due to the close connection of these branches with the bony structures of the maxilla and mandible. As a result, injuries of the lingual nerve and inferior alveolar nerve take place within routine maxillofacial surgery procedures, including local anesthetic injection, wisdom tooth surgery, and dental implant placement, resulting in paresthesia and dysesthesia. During the last three decades, low-level lasers (LLL) have been frequently used in various medical fields. Lately, this application has increased in several sectors. Methods and materials: This experiment was designed to explore the effect of low-level laser therapy (LLLT) with Nd:YAG on the paresthesia and dysesthesia of the lower lip. This ethics committee of Tbzmed, Tabriz, Iran, proved the present experiment with ethical code: IR.TBZMED.REC.1401.839. Results: After completing 10 sessions of laser therapy for the case group consisting of 25 patients with lower lip anesthesia, the visual analog scale index results revealed that following six sessions of laser therapy, a significant difference appeared in contrast to the control group. Also, according to the two-point tests, significant difference among the experimental and the control group appeared after ninth session of the laser therapy. Conclusions: Altogether, these data suggested LLLT with Nd:YAG as an effective treatment option for decreasing the anesthesia of the lower lip.

Comparison of Efficacy of Lidocaine and Articaine as Inferior Alveolar Nerve Blocking Agents in Patients with Symptomatic Irreversible Pulpitis: Randomized Controlled Trial

Background and Objectives: Lidocaine Hydrochloride has been the standard choice for local anesthesia in dentistry and Articaine's unique structure and growing popularity make it a viable alternative. Due to contradictory results in prior research and a scarcity of trials conducted in the Pakistani population, this study aims to compare the anesthetic efficacy of Lidocaine with Articaine for inferior alveolar nerve blocks in patients with symptomatic irreversible pulpitis. Materials and Methods: This double-blinded, randomized controlled trial included 152 patients who were selected by consecutive non-probability sampling. The participants included patients who presented with symptomatic irreversible pulpitis in mandibular posterior teeth (molars and premolars) and depicted normal apical tissue radiographically. The patients were equally and randomly divided into two groups. The control group received 2% Lidocaine Hydrochloride injections, and the experiment group received 4% Articaine Hydrochloride injections. Participants scored their pain on the HP-VAS both before and after the administration of anesthesia. A value of 54 mm or less on the scale indicated effective anesthesia. The data obtained were analyzed using SPSS. Chi-square test was applied to analyze data for statistical significance. Results: There was no statistically significant difference in the efficacy of the two anesthetic agents. During access cavity preparation, Lidocaine demonstrated a success rate of 93%, whereas Articaine exhibited a slightly higher success rate of 97%. During initial instrumentation, the success rates for Lidocaine and Articaine were 72% and 71%, respectively. This suggests that both Lidocaine and Articaine were effective in achieving anesthesia during the dental procedure in patients with symptomatic irreversible pulpitis, with Articaine showing a slightly better success rate, although the difference was not statistically significant. Conclusions: The anesthetic efficacy of Articaine is similar to that of lidocaine in subjects with symptomatic irreversible pulpitis. Hence, Articaine can serve as an alternative to Lidocaine for local anesthesia administration in dentistry.