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Introduction: The peripheral taste sensitivity is transmitted to the brain stem by the facial nerve, via the chorda tympani, and by the glossopharyngeal and vagus nerves. The trigeminal nerve is also involved in the sensory analysis of food. The objective of this study was to test the hypothesis of a modulation of taste perception by sensory afferents from the inferior alveolar nerve (IAN) in humans, by measuring electrogustometricdetection thresholds (EGM) before and after anesthesia of trigeminal afferents. Material and methods: A group A (n = 60) submitted to regional anesthesia of the inferior alveolar nerve (IAN) and a control group (n = 60) submitted to anesthesia of the maxillary nerve were compared before (stage 0) and after (stage 1) anesthesia. EGMrecordings were performed by an examiner single blinded to the anesthesia procedure, at 9 symmetrical lingual tongue loci: tip lateral (Tr, Tl) and central (T), median dorsal (Dr, Dl), posterior lateral edges (Er, El) and posterior dorsal (Pr, Pl). The correlation between the type of anesthesia and the EGM thresholds was calculated using the Spearman rho test and the intra- and intergroup comparisons, using Mann-Whitney tests and Wilcoxon, with a level of significance set at 0.05. Results: The average values of thresholds EGM group A were significantly increased after anesthesia of the NAI at all lingual loci (p <0.005). The highest thresholds (in μ0: Dr = 30.7 ± 9.4; Dl = 31 ± 9.5 vs Stage 1: 68.5 ± Dr = 44.6; dl = 63.3 ± 35.3) and at the posterior part of the tongue (stage 0: Pr = 20.9 ± 5.4; Pl = 21 ± 5.1 vs Stage 1: Pr = 37.3 ± 25, 4; Pl = 35.9 ± 16.6). No significant difference was observed in the control group for any of the nine loci before and after anesthesia. There was a significant correlation between EGM and regional anesthesia thresholds of the NAI at the 9 EGM recording tongue loci (p < 0.001). Conclusion: These results demonstrate that regional anesthesia of dental afferents of the NAI causes an increase of the electrogustometricdetection thresholds. [ABSTRACT FROM AUTHOR]

Introduction: The gustatory modality is provided by a branch of the facial nerve, the chorda tympani and the glossopharyngeal and vagus nerves. The trigeminal nerve is also involved in the sensory analysis of food. The objective of this study was to test the validity of the modulation of taste perception by sensory afferents of the Inferior Alveolar Nerve (IAN) in humans. Materials and methods: A group A (n = 100) submitted to regional anesthesia of the IAN and a control group (n = 100) submitted to maxillary nerve anesthesia were selected. The study was performed single-blind. Measurements of EGM detection thresholds were performed before and after anesthesia without the researcher knowing if the subject received anesthesia, or what type of anesthesia was administered. The thresholds were tested at 9 points of the tongue: first at the tip of the tongue and at the back, then at the lateral posterior edges, and finally, at the most posterior part of the back of the tongue. The correlation between the type of anesthesia and EGM thresholds was performed with Spearman's rho test, and intra- and intergroup comparisons with Mann-Whitney and Wilcoxon tests. The level of significance was set at p ≤ 0.05. Results: Group A showed an increase in the mean values of EGM thresholds after regional anesthesia of the NAI afferents at all lingual sites. The highest thresholds (in μA) were found at the back (stage 0: Dr = 31.3 ± 10.3; Dl = 31.5 ± 10.2 against stage 1: Dr = 71.5 ± 46.9; Dl = 56.4 ± 33) and the posterior part of the tongue (stage 0: Pr = 20.8 ± 6.2; Pl = 20.8±6.2 against stage 1: Pr = 38.7 ± 26.5; Pl = 32.1 ± 15.9). In this group the difference in thresholds before and after regional anesthesia of the IAN was statistically significant (p ≤ 0.005) for all measured sites. The control group showed no significant increase in the mean values of thresholds after anesthesia of afferents of the maxillary nerve at the 9 sites (p: NS). In the age group 18-29 years, regardless of age, all sites underwent a significant increase in EMG levels (p ≤ 0.05) after regional anesthesia of the IAN, in contrast to the group submitted to anesthesia of the maxillary nerve, where no increase was observed. There is a significant correlation between EMG thresholds and regional anesthesia of the afferents of the IAN for the 9 points of lingual stimulation (p < 0.001, Spearman's rho test). Conclusion: These results show that regional anesthesia of the dental afferents of the IAN causes a change in electrogustometry detection thresholds. [ABSTRACT FROM AUTHOR]