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Purpose: Inferior alveolar nerve (IAN) and lingual nerve (LN) blocks are commonly performed using the intraoral landmark techniques. However, these methods have a risk of unanticipated nerve and arterial injury or a higher failure rate. We developed a novel extraoral approach for the IAN and LN blocks, the "inferior alveolar nerve block mandibular angle approach (IANB-MA)," using ultrasound guidance. The mechanism of action of this nerve block was examined anatomically, and its clinical feasibility was reported., Methods: We performed the IANB-MA on four cadavers using different dye volumes (2, 4, 6 and 8 mL). The ultrasound probe was placed on the lower edge of the mandibula of each cadaver, and the needle was advanced to the mandibular inner surface. Blue acrylic paint solution was injected, and its spread was evaluated by dissection., Results: Our study showed that the medial pterygoid muscle fascia was stained in all cadavers. The dye reached the LN consistently, and the IAN was stained with higher volumes (6 mL and 8 mL). The pterygomandibular space was filled with 6 mL and 8 mL of the dye. The IANB-MA successfully reduced pain in three patients with trigeminal neuralgia, tongue or jaw pain., Conclusions: The IANB-MA is a novel ultrasound-guided approach to the IAN and the LN. The clinical feasibility and effectiveness of this technique were confirmed in our patients. It may be a good alternative analgesic approach to other conventional approaches., Competing Interests: Declarations. Conflict of interest: All authors have no conflicts of interest., (© 2024. The Author(s) under exclusive licence to Japanese Society of Anesthesiologists.)

Blinded techniques to desensitize the inferior alveolar nerve (IAN) include intraoral, angled, and vertical extraoral approaches with reported success rates of 100%, 73%, and 59%, respectively. It has not been determined whether an ultrasound-guided extraoral approach is feasible. Further, the fascicular nature of the inferior alveolar and lingual nerves of the horse has not been described. The objectives of this study were to describe a low-volume ultrasound-guided vertical extraoral inferior alveolar nerve block technique and to describe the fascicular nature of these nerves. An ultrasound-guided approach to the IAN was conducted with a microconvex transducer and an 18-G, 15-cm spinal needle using a solution containing iodinated-contrast and methylene blue dye. Accuracy was assessed by contrast visualized at the mandibular foramen on computed tomography (CT) and methylene blue dye staining of the nerves on gross dissection. Sections of inferior alveolar and lingual nerves were submitted for histological analysis. Assessment by CT and dissection determined success rates of 81.3% and 68.8%, respectively; 68.8% of injections had inadvertent methylene blue dye staining of the lingual nerve. Nerve histology revealed both the inferior alveolar and lingual nerves to be multifascicular in nature. Mean fascicle counts for the inferior alveolar and lingual nerves were 29 and 30.8, respectively. The technique is challenging and no more accurate than previously published blinded techniques. Any extraoral approach to the IAN is likely to also desensitize the lingual nerve.

We examined blood flow in the submandibular gland (SMGBF) and sublingual gland (SLGBF) during electrical stimulation of the central cut end of the lingual nerve (LN) in the urethane-anesthetized rats using a laser speckle imaging flow meter. LN stimulation elicited intensity- and frequency-dependent SMGBF and SLGBF increases, and the magnitude of the SMGBF increase was higher than that of the SLGBF increase. The increase in both glands was significantly inhibited by intravenous administration of the autonomic cholinergic ganglion blocker hexamethonium. The antimuscarinic agent atropine markedly inhibited the SMGBF increase and partly inhibited the SLGBF increase. The atropine-resistant SLGBF increase was significantly inhibited by infusion of vasoactive intestinal peptide (VIP) receptor antagonist, although administration of VIP receptor antagonist alone had no effect. The recovery time to the basal blood flow level was shorter after LN stimulation than after administration of VIP. However, the recovery time after LN stimulation was significantly delayed by administration of atropine in a dose-dependent manner to the same level as after administration of VIP. Our results indicate that 1) LN stimulation elicits both a parasympathetic SMGBF increase mainly evoked by cholinergic fibers and a parasympathetic SLGBF increase evoked by cholinergic and noncholinergic fibers, and 2) VIP-ergic mechanisms are involved in the noncholinergic SLGBF increase and are activated when muscarinic mechanisms are deactivated., (Copyright © 2015 the American Physiological Society.)

Patients with burning mouth syndrome (BMS) report burning sensation and pain involving the tongue and oral mucosa without any apparent medical or dental cause. The pathogenesis of this syndrome remains unclear and there is currently no standard treatment. BMS is, therefore, often misdiagnosed and its management is complex. This lack of clinical expertise may result in decreased health-related quality of life and increased psychological distress among patients with BMS. The present case report involves a 77-year-old female patient with BMS refractory to conventional treatment with nerve block and medication, who was successfully treated with duloxetine. Duloxetine may become a new therapeutic option in the management of BMS., (© The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.)

Peripheral nerve blocks with local anaesthesia are routinely utilized in oral surgical procedures to achieve anaesthesia at the operative site. A number of local tissue factors as well as systemic conditions and medications may alter the onset, depth and duration of peripheral nerve blocks. This article describes two cases of extremely prolonged anaesthesia in patients treated with chronic oral lithium carbonate who had been administered inferior alveolar, lingual, long buccal, greater palatine and posterior superior alveolar nerve blocks with lidocaine with adrenaline for surgical removal of an upper and a lower third molar tooth. A possible relation with systemic lithium therapy and its probable mode of action are explored., (Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Extraction of mandibular third molars is one of the most common procedures in oral and maxillofacial surgery, and it is normal practice to extract both teeth at one visit under general anaesthesia. However, when both teeth are extracted under local anaesthesia, bilateral inferior alveolar and lingual nerve blocks are required, which is a subject of debate among clinicians. Much of the controversy surrounds the safety and efficacy of bilateral anaesthesia even though many surgeons use local anaesthetic solutions for perioperative and postoperative pain relief after day case general anaesthesia with no reports of unwanted effects. The evidence presented in this review explores published research for and against the use of unilateral and bilateral inferior alveolar and lingual nerve blocks., (Copyright © 2013 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Stimulation of the trigeminal nerve can elicit various cardiovascular and autonomic responses; however, the effects of anesthesia with pentobarbital sodium on these responses are unclear. Pentobarbital sodium was infused intravenously at a nominal rate and the lingual nerve was electrically stimulated at each infusion rate. Increases in systolic blood pressure (SBP) and heart rate (HR) were evoked by lingual nerve stimulation at an infusion rate between 5 and 7 mg·kg(-1)·h(-1). This response was associated with an increase in the low-frequency band of SBP variability (SBP-LF). As the infusion rate increased to 10 mg·kg(-1)·h(-1) or more, decreases in SBP and HR were observed. This response was associated with the reduction of SBP-LF. In conclusion, lingual nerve stimulation has both sympathomimetic and sympathoinhibitory effects, depending on the depth of pentobarbital anesthesia. The reaction pattern seems to be closely related to the autonomic balance produced by pentobarbital anesthesia.

In the orofacial area, noxious stimulation of the orofacial structure in the trigeminal region evokes parasympathetic reflex vasodilatation, which occurs via the trigeminal spinal nucleus (Vsp) and the inferior/superior salivatory nucleus (ISN/SSN). However, the neurotransmitter involved in the inhibitory synaptic inputs within these nuclei has never been described. This parasympathetic reflex vasodilatation is suppressed by GABAergic action of volatile anesthetics, such as isoflurane, sevoflurane, and halothane, suggesting that medullary GABAergic mechanism exerts its inhibitory effect on the parasympathetic reflex via an activation of GABA receptors. The aim of the present study was to determine the role of GABA(A) and GABA(B) receptors in the Vsp and the ISN in regulating the lingual nerve (LN)-evoked parasympathetic reflex vasodilatation in the lower lip. Under urethane anesthesia (1g/kg), change in lower lip blood flow elicited by electrical stimulation of the LN was recorded in cervically vago-sympathectomized rats. Microinjection of GABA (10 μM; 0.3 μl/site) into the Vsp or the ISN significantly and reversibly attenuated the LN-evoked parasympathetic reflex vasodilatation. Microinjection of the GABA(A) receptor-selective agonist muscimol (100 μM; 0.3 μl/site) or the GABA(B) receptor-selective agonist baclofen (100 μM; 0.3 μl/site) into the Vsp or the ISN significantly and irreversibly reduced this reflex vasodilatation, and these effects were attenuated by pretreatment with microinjection of each receptor-selective antagonists [GABA(A) receptor selective antagonist bicuculline methiodide (1mM; 0.3 μl/site) or GABA(B) receptor selective antagonist CGP-35348 (1mM; 0.3 μl/site)] into the Vsp or the ISN. Microinjection of these antagonists alone into the Vsp or the ISN had no significant effect on this reflex vasodilatation. In addition, microinjection (0.3 μl/site) of the mixture of muscimol (100 μM) and baclofen (100 μM) into the Vsp or the ISN also significantly reduced this reflex vasodilatation. These results suggest that medullary GABA signal transduction inhibits the parasympathetic reflex vasodilatation in the rat lower lip via GABA(A) and GABA(B) receptors in the Vsp and the ISN., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Purpose: The aim of this study was to evaluate the distribution and absorption of local anesthetic solutions in inferior alveolar nerve block using magnetic resonance imaging., Materials and Methods: Forty healthy volunteers were divided into 4 groups and injected with 1.5 mL for inferior alveolar nerve block and 0.3 mL for lingual nerve block. The solutions used for the different groups were 2% lidocaine, 2% lidocaine with 0.125 mg/mL epinephrine, 4% articaine with 0.006 mg/mL epinephrine, and 4% articaine with 0.012 mg/mL epinephrine. All subjects had axial T2-weighted and fat-suppressed images at 0, 60, and 120 minutes after injection. The localization, area, and intensity (signal characteristics) of the solutions were analyzed and onset and duration times of the anesthesia were recorded., Results: There were no significant differences between groups with regard to the intensity and area of the solutions at 0, 60, and 120 minutes after injection, but differences were found within each group., Conclusions: No between-group differences were found on magnetic resonance imaging in the distribution and absorption of lidocaine with or without epinephrine and articaine with 0.006 and 0.012 mg/mL epinephrine. All solutions were noticeably absorbed at 120 minutes after injection., (Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Prolonged anaesthesia may occur following dental local anaesthetic blocks. This paper reviews the possible mechanisms of injury. Direct injury to the nerve by the needle, although commonly thought to be the mechanism, is unlikely. It is much more likely that the injury is from neurotoxicity and/or interference with the vascularization of the nerve., Methods: Estimation of the frequency of injury was complicated by the fact that although local anaesthetics are prescription-only (S4) drugs, they are supplied without prescription by dental supply houses. Unlike all other S4 drugs, there is no statutory requirement to record supply. The pharmaceutical and supply houses relied on that and 'commercial confidentiality' to not supply information., Results: An informed estimate of 1 in 27 415 was made but this figure has wide confidence limits. Management of cases of prolonged anaesthesia following local anaesthetic injection is discussed., Conclusions: Patients who suffer this uncommon complication suffer considerable distress and feel injured, so care must be exhibited in their management. Specialist referral is recommended., (© 2011 Australian Dental Association.)

This study investigated the extent of complete anaesthesia from buccal nerve block. 40 healthy Thai patients (20 males; 20 females) requiring buccal nerve block for surgery were studied. After the buccal nerve was blocked, the buccal mucosa was explored using a sharp probe to map out the extent of anaesthesia. The operation was carried out after inferior alveolar and lingual nerve block. The extent of the anaesthesia was mainly from the retromolar area to the second molar, followed by the first molar to the second premolar, whilst the first premolar to the central incisor was the area least affected. An important finding of this study was that the anaesthetized extent of some patients extended to the anterior region on the same quadrant. This study showed the affected areas of buccal nerve anaesthesia extended through the buccal mucosa from the first premolar to the central incisor in some patients. It can serve as another informative indication for lower anterior surgery., (Copyright © 2011 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Alterations to normal oral sensory function can occur following restorative and surgical dental procedures. Paresthesia is defined as an abnormal sensation, such as burning, pricking, tickling, or tingling. Paresthesias are one of the more general groupings of nerve disorders known as neuropathies. This article reviews the extent of this oral complication as it relates to dental and surgical procedures, with specific emphasis on paresthesias associated with local anesthesia administration. This review establishes a working definition for paresthesia as it relates to surgical trauma and local anesthesia administration, describes the potential causes for paresthesia in dentistry, assesses the incidence of paresthesias associated with surgery and local anesthesia administration, addresses the strengths and weaknesses in research findings, and presents recommendations for the use of local anesthetics in clinical practice., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Background: Several studies have suggested that the likelihood of paresthesia may depend on the local anesthetic used. The purpose of this study was to determine if the type of local anesthetic administered had any effect on reports of paresthesia in dentistry in the United States., Methods: The authors obtained reports of paresthesia involving dental local anesthetics during the period from November 1997 through August 2008 from the U.S. Food and Drug Administration Adverse Event Reporting System. They used chi(2) analysis to compare expected frequencies, on the basis of U.S. local anesthetic sales data, with observed reports of oral paresthesia., Results: During the study period, 248 cases of paresthesia occurring after dental procedures were reported. Most cases (94.5 percent) involved mandibular nerve block. The lingual nerve was affected in 89.0 percent of cases. Reports involving 4 percent prilocaine and 4 percent articaine were 7.3 and 3.6 times, respectively, greater than expected (chi(2), P < .0001) on the basis of local anesthetic use by U.S. dentists., Conclusions: These data suggest that paresthesia occurs more commonly after use of 4 percent local anesthetic formulations. These findings are consistent with those reported in a number of studies from other countries., Clinical Implications: Until further research indicates otherwise, dentists should consider these results when assessing the risks and benefits of using 4 percent local anesthetics for mandibular block anesthesia.

Background: Transient, isolated lingual nerve neuropraxia is a rare complication following general anaesthesia. Reports implicate airway manipulation and we describe two new cases associated with laryngeal mask airway (LMA) and review the related English language literature., Results: Unilateral numbness and loss of taste on the anterior tongue were the characteristic symptoms. Collation of literature data (median and range) with that from the new cases showed: patient age was 38 (20-61) years and female to male ratio was 1.2:1. Surgery time was 62.5 (20-150) min and symptom duration was 28 (7-120) days., Conclusion: Lingual neuropraxias reported have been transient and patients can be advised, despite disturbing symptoms, that recovery is anticipated in about 1 month. Lingual neuropraxia reports are becoming more frequent, perhaps associated with increasing LMA use. Research is recommended as modification to LMA cuff volume, pressure and/or position within the oral cavity might ameliorate the entity.

Burning mouth syndrome (stomatodynia) is associated with changes of a neuropathic nature the main location of which, peripheral or central, remains unknown. A randomised, double-blind crossover design was used to investigate the effects of lingual nerve block on spontaneous burning pain and a possible correlation with the effects of topical clonazepam, the patient's response to a psychological questionnaire, and the taste and heat thresholds. The spontaneous burning was measured with a visual analogue scale (VAS) just before and 15 min after injection. The decreases in VAS score after lidocaine or saline injection were not significantly different (2.7+/-3.9 and 2.0+/-2.6, respectively; n=20). However, two groups of patients could be identified: in a "peripheral group" (n=10) the VAS decrease due to lingual nerve injection was 4.3+/-3.1cm after lidocaine and 0.9+/-0.3 cm after saline (p=0.02). In a "central group" (n=7), there were an increase in pain intensity score (-0.8+/-2.6 cm) after lidocaine and a decrease (1.5+/-3.0 cm) after saline (p=0.15). An increase in the hospital anxiety and depression (HAD) score and a decreased taste sensitivity and heat pain threshold of painful oral area were seen in patients compared with age-and-sex-matched controls (p<0.05). Topical clonazepam treatment tended to be more effective (p=0.07) and HAD score lower (p<0.03) in the peripheral than in the central group. These results suggest that the neuropathic disorder associated with stomatodynia may be predominantly peripheral, central or mixed depending on the individual. Topical application of clonazepam and HAD may serve as indicators of which mechanism is dominating., (Copyright 2009 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.)

Abnormal neural activity generated at a site of nerve injury is thought to contribute to the development of dysaesthesia. Vanilloid receptor 1 (TRPV1), a transducer of noxious stimuli, may be involved in the initiation of this abnormal activity and could provide a useful therapeutic target. We investigated the effect of a specific TRPV1 antagonist (SB-750364) on injury-induced discharge in the lingual nerve. In 12 anaesthetised adult ferrets the left lingual nerve was sectioned and animals were allowed to recover for 3-7 days. In terminal experiments under general anaesthesia, the nerve was re-exposed and electrophysiological recordings made from spontaneously active axons in fine filaments dissected from the nerve central to both the injury site and the junction with the chorda tympani. SB-750364 was infused via the cephalic vein in order to achieve three increasing but stable systemic blood levels of the compound (0.3, 1.0 and 3.0 microM). Twenty-eight spontaneously active units were studied, with discharge frequencies ranging from 0.02 to 4.9 Hz. There was a significant reduction in spontaneous activity in 17 units (61%) at 1.0 microM or less of SB-750364 (p<0.01; Friedman test with Dunn's multiple comparisons). A further 4 units (14%) showed a significant reduction in activity at 3.0 microM (p<0.01). In the remaining 7 units (25%) the discharge was unaffected (p>0.05). These data show that the TRPV1 antagonist SB-750364 can reduce the level of spontaneous activity initiated in some axons following lingual nerve injury.

The aim of this study was to compare the effectiveness of 2 different volumes of anesthetic solution for a premolar-molar extraction, and to determine the onset of complete mandibular conduction anesthesia via a Gow-Gates mandibular block. One operator performed 32 blocks with a 27-gauge needle on patients who required a dental extraction: 16 blocks using 1.8 mL of anesthetic solution, and 16 blocks using 3.6 mL of anesthetic solution. The parameters evaluated were frequency of successful anesthesia and onset of complete anesthesia. Significant differences (P < .005) were observed in the evaluation of volume: the 3.6 mL group yielded a higher success rate (82.5%) than the 1.8 mL group (17.5%). The onset of complete conduction anesthesia was achieved in 8 minutes by 56% of the subjects (9 of 16) with 3.6 mL and only one subject in 16 (6%) with 1.8 mL. A larger volume of anesthetic solution (3.6 mL) is required to achieve a higher success rate and a faster onset of action for a dental extraction without the use of reinforcement anesthesia. The volume of anesthetic solution is indirectly proportional to the onset of complete anesthesia. A premolar-molar extraction can be done, with 3.6 mL of anesthetic solution, in more than 50% of the patients 8 minutes after injection.

We conducted a prospective, randomised study on the use of pre-emptive analgesia in 45 patients who had bilateral impacted third molars removed. Bupivacaine 0.5% with adrenaline 1:200,000 was injected on one side, the other side acting as control. A visual analogue scale was used to measure the extent of postoperative pain. There was a significant reduction (p = 0.05) in postoperative pain on the injected side at 6, 12, and 72 h and an overall reduction in pain up to 7 days.

By measuring spectral characteristics of the sibilant /s/ this study investigated whether the reduced orosensory feedback caused by lingual nerve impairment affects the acoustics and articulation of sibilants. A further goal was to examine speakers' capability to compensate for the deviant control of the delicate movements required for the proper production of /s/ by experimentally modifying the function of the tongue in a way that reduces the necessary somatosensory information in articulation. Five healthy men with no speech, language or hearing abnormalities were enrolled. They produced the sibilant /s/ in a variety of phonetic contexts in two sessions: first in normal conditions and then with local anaesthesia of the right lingual nerve. From the speech samples, the spectral characteristics of the sibilant sound (i.e. the centre of gravity, standard deviation, skewness and kurtosis) were analysed acoustically. The results showed that the reduced tactile sensation has effects on the tongue function resulting in individual and variable spectral alterations. The variation between different speakers indicates individual ability to compensate for the effects caused by the sensory dysfunction of the tongue. It seems, therefore, that the compensatory mechanisms for speech production are highly speaker-dependent.

Fifty-four injection injuries in 52 patients were caused by mandibular block analgesia affecting the lingual nerve (n=42) and/or the inferior alveolar nerve (n=12). All patients were examined with a standardized test of neurosensory functions. The perception of the following stimuli was assessed: feather light touch, pinprick, sharp/dull discrimination, warm, cold, point location, brush stroke direction, 2-point discrimination and pain perception. Gustation was tested for recognition of sweet, salt, sour and bitter. Mandibular block analgesia causes lingual nerve injury more frequently than inferior alveolar nerve injury. All grades of loss of neurosensory and gustatory functions were found, and a range of persisting neurogenic malfunctions was reported. Subjective complaints and neurosensory function tests indicate that lingual nerve lesions are more incapacitating than inferior alveolar nerve lesions. Unlike most mechanical injuries after surgery, injection injuries were not followed by a course of spontaneous improvement of neurosensory and/or gustatory function. This may indicate neurotoxicity as a central aetiological factor. Fifty-four percent of the nerve injuries were associated with Articaine 4%, and a substantial increase in the number of injection injuries followed its introduction to the Danish market.

Volatile anesthetics have been known to suppress parasympathetic reflex vasodilatation in the lower lip and palate. However, in the submandibular gland, little is known about the effects of these anesthetics on the parasympathetic vasodilatation elicited by reflex and direct (i.e., non-reflex) activation of the parasympathetic vasodilator mechanisms. Although both parasympathetic vasodilatations were inhibited by isoflurane in a concentration- and time-dependent manner, the effects of continuous administration of the alpha(1)-adrenoceptor agonist methoxamine were markedly different: The reflex vasodilatation was not affected by methoxamine, while the direct vasodilatation was significantly reduced. Picrotoxin (GABA(A) receptor antagonist) attenuated the inhibitory effect of isoflurane on direct vasodilatation and the systemic arterial blood pressure. These findings suggest that the isoflurane-induced inhibitory effects on direct vasodilatation are produced by a decrease of peripheral vascular tone by GABAergic mechanisms, whereas those on the reflex vasodilatation are produced exclusively by the inhibition of the reflex center.

Several recent studies with transcranial magnetic stimulation (TMS) have demonstrated changes in motor evoked potentials (MEPs) in human limb muscles following modulation of sensory afferent inputs, but little is known about the regulation of the human tongue motor control. To test the effect of local anesthesia (LA) of the lingual nerve and topical application of capsaicin stimulation on tongue MEPs. Fourteen volunteers participated (21-30 years) in two randomized sessions; before, during a nerve block of the lingual nerve or topical capsaicin application (30 microl 5%) on the tongue, and after anesthesia or pain had subsided. EMG electrodes were placed on the tongue and the first dorsal interosseous (FDI) muscle (control). EMG signals were amplified, filtered (20 Hz-1 kHz), and sampled at 4 kHz (Nicolet, USA). TMS were delivered with a figure-of-eight coil (Magstim 200, UK). Scalp sites at which EMG responses were evoked in the relaxed tongue or FDI at the lowest stimulus strength were determined, i.e., motor threshold (T). MEPs were assessed using stimulus-response curves in steps of 10% T. Eight stimuli were presented at each stimulus level. The proximal hypoglossal nerve was activated by TMS delivered over the parieto-occipital skull distal to the right ear. Eight stimuli were delivered at 50% of maximum stimulator output. ANOVAs were used to analyze latency and peak-to-peak amplitudes. Capsaicin evoked mild pain (2.8+/-0.5), and a strong burning sensation (6.2+/-0.4) on 0-10 visual analogue scales. MEP amplitudes in tongue and FDI were not influenced by capsaicin (P>0.44) but by stimulus strength (P<0.001). MEP latencies in tongue (8.9+/-0.2 ms) and FDI (22.4+/-0.4 ms) were not affected by capsaicin (P>0.19). Hypoglossal nerve stimulation evoked a short-latency (3.6+/-0.9 ms) response (mean amplitude 65+/-9 microV); but was unaffected by capsaicin (P>0.54). LA did not have any effect on FDI MEPs but was associated with a significant facilitation of tongue MEPs at T+50% and T+60% about 50 min after the nerve block in the recovery phase. Also in this condition, the direct motor responses evoked by hypoglossal nerve stimulation remained constant. No direct effect of a strong burning sensation could be shown on peripheral or central corticomotor pathways to the relaxed tongue musculature, however, LA of the lingual nerve (cranial nerve V) seems able to induce a delayed change in corticomotor control of tongue musculature (cranial nerve XII) possibly related to unmasking effects at the cortical level but not completely excluding excitability changes at the brain stem level.

The inferior alveolar nerve (IAN) block is the most common method for obtaining mandibular anaesthesia in dental practice but it is estimated to have a success rate of only 80 to 85 per cent. Causes of failure include problems with operator technique and anatomical variation between individuals. This case report involves a patient who received IAN blocks on two separate occasions that resulted in only partial anaesthesia of the ipsilateral side of the mandible. Radiographic assessment disclosed the presence of bifid mandibular canals that were present bilaterally and that may have affected the outcomes of the local anaesthetic procedures. Previous studies of bifid mandibular canals are reviewed and suggestions provided that should enable clinicians to differentially diagnose, and then manage, cases where IAN blocks result in inadequate mandibular anaesthesia.

Purpose: Objective testing was an aim of the examination whether excluding the sensory zone of the tongue is causing the slope of the gustatory sensitivity after alcoholic blocks., Material and Methods: Material is embracing 15 ill neuralgia treated in a maxillary-facial surgical clinic in Poznań because of neuralgia, in the age on average 60 years, which one should block the sensory leadership of the mandibular nerve with alcohol at and additionally lingual branch. There were 6 women and 9 men amongst treated patients., Results: Objective electrogustomertic examinations demonstrated worsening the gustatory sensitivity with the Pruszewicz's method at 86.7% of ill, on the alcoholised side of the lingual nerve, however at stayed impressions of the gustatory sensitivity were located in upper limits of the norm., Conclusion: Worsening gustatory impressions isn't forming with injuring of the of chorda tympani fibres but it is an effect of bearing feeling surface in the area of the innervation through the lingual nerve after of it alcoholization.

Previous studies have shown that the development of ectopic activity from damaged axons following nerve injury may contribute to the aetiology of sensory disturbances, including dysaesthesia. Pharmacological manipulation of this activity could provide a method of treatment for this intractable condition. In this study we have investigated the effect of carbamazepine, an anti-convulsant, as it is known to have membrane stabilising properties. In eight anaesthetised adult ferrets the left lingual nerve was sectioned and the animals allowed to recover for 3 days. Then, in terminal experiments under general anaesthesia, the nerve was re-exposed and electrophysiological recordings were made from spontaneously active units in fine filaments dissected from the nerve proximal to the injury site. Carbamazepine in a modified cyclodextrin (hydroxypropyl-beta-cyclodextrin) was administered intravenously in increments, in order to achieve a progressively increasing systemic concentration, and serum levels were determined at the point that activity ceased. Twenty-one spontaneously active units were studied, with conduction velocities of 2.1-28.9 m s(-1) and discharge frequencies of 0.25-15.3 Hz. Spontaneous activity ceased in 13 units with a serum concentration of carbamazepine ranging from 3.5 to 8.4 mg/l, which was within the normal therapeutic range (4-12 mg/l). Four units ceased activity with carbamazepine levels above the therapeutic range (15.4-17.2 mg/ml), but the remaining four continued to discharge throughout the recording period. These data suggest that systemic carbamazepine can reduce the level of spontaneous activity initiated in some axons following lingual nerve injury.

The present study attempts to determine whether the onset of swallowing is affected by bilateral lingual and inferior alveolar nerve anesthesia and by raising the occlusal vertical dimension by wearing an occlusal bite plate. Twenty young male volunteers were selected and asked to chew and swallow corned beef and a corned beef and liquid mixture in their usual manner before and after modifications were made. Oral and pharyngeal swallowing was investigated using videofluoroscopic examination in the lateral plane. Eight objective indicators, including oral containment time, swallowing threshold, and pharynx-to-swallow intervals were estimated. Oral containment time, total sequence duration, total number of chews, and total number of swallows of the two test foods were significantly different before and after the modifications. Individual pharynx-to-swallow intervals also varied. The results indicate that modification of the masticatory condition affects the onset of swallowing and that changes in the onset varied among the participants.

Brain-derived neurotrophic factor (BDNF) is important in the response to peripheral nerve injury and may enhance regeneration. We have assessed its role in the functional recovery of sensory afferents and autonomic efferents after repair of the chorda tympani and lingual nerves in the cat. Six months after entubulation repair, with or without the incorporation of BDNF at the repair site, the recovery of secretomotor and vasomotor efferents was determined by recording salivary flow from the submandibular gland and temperature changes on the tongue surface, each evoked by stimulation of the repaired nerve. Electrophysiological recordings from the lingual and chorda tympani nerves proximal to the repair were undertaken to characterise mechanosensitive, thermosensitive, and gustatory afferents. When compared with data from uninjured control animals, both repair groups showed changes in receptor sensitivity and spontaneous discharge, and persistent reductions in conduction velocity, proportion of gustatory and thermosensitive units, rate of salivary secretion, and vasomotor responses. Comparisons between the outcome of repair with or without BDNF revealed few differences. In the BDNF group, fewer units in the chorda tympani responded to gustatory or thermal stimuli and the sensitivity of the gustatory units was lower. The conduction velocity of afferents in the lingual nerve was also lower, but the mechanoreceptive field size was higher. Thus, despite its known trophic role in the gustatory system, BDNF had not enhanced recovery of these or other fibre populations. We conclude that the application of BDNF to a site of lingual nerve repair has a negative effect on the long-term outcome.

Investigations into the aetiology of nerve injury-induced dysaesthesia have revealed the development of spontaneous and mechanically-induced activity from damaged axons. Pharmacological manipulation of this activity could provide a method of treatment for this intractable condition. This study has investigated the effect of a corticosteroid applied to the injury site, as these agents are known to reduce inflammation and scarring. In 24 anaesthetised adult ferrets the left lingual nerve was sectioned and the animals allowed to recover. In eight of these animals the nerve was re-exposed under anaesthesia after 1 month and 100 microl of corticosteroid (triamcinolone hexacetonide, 20 mg/ml) was injected into and around the injury site. In eight others, 100 microl of the steroid carrier was injected, and the eight remaining animals were used as controls. In terminal experiments under general anaesthesia, 3 months after the initial injury, electrophysiological recordings were made from axons in fine filaments dissected from the nerve central to both the injury site and junction with the chorda tympani nerve. Spontaneous activity (SA) was found in approximately 13% of units in control animals, 12% following the application of steroid, and 14% in the carrier group. Mechanically-induced activity at the injury site was found in approximately 13% of units in controls, significantly fewer after the application of steroid 4% (P<0.001) and 12% in the carrier group. These data suggest that local application of the corticosteroid triamcinolone hexacetonide could reduce the level of mechanically-induced, but not spontaneous, dysaesthesia following lingual nerve injury.

Objective: To determine whether bilateral lingual and inferior alveolar nerve anesthesia affects the onset of swallowing including masticatory function., Study Design: Twenty young male volunteers were asked to chew and swallow corned beef and then a mixture of corned beef and liquid in their usual manner before and after local anesthesia. The oral and pharyngeal swallowing was investigated using videofluoroscopic examination in a lateral plane. Eight objective indicators including oral containment time, swallowing threshold, and pharynx-to-swallow interval were measured., Results: Oral containment time and total sequence duration, total number of chews, and total number of swallows for the 2 test foods varied significantly between those before and after anesthesia. Individual pharynx-to-swallow intervals varied with both foods without remarkable increases or decreases in the swallow duration and cricopharyngeal opening time., Conclusion: Bilateral lingual and inferior alveolar nerve anesthesia may affect early swallowing; changes in the onset of swallowing varied among the participants.

Purpose: The effects of lingual nerve impairment on the phonetic quality of diphthongs were studied by analyzing changes in their main acoustic features when anesthetic was injected into the lingual nerve to partly block the normal neural feedback mechanisms in speech., Patients and Methods: The speech material consisted of 8 diphthongs in word context produced by 7 male speakers. Every utterance was repeated 10 times using normal speech rate and intonation with and without the anesthesia (Ultracain D-Suprarenin, 0.8 mL; Aventis Pharma Deutscland GmpH, Frankfurt am Main, Germany). In addition, 1 male speaker with permanent nerve impairment was studied. The acoustic features (F1, F2, F0, and duration) were analyzed using Computerized Speech Laboratory (CSL 4300B; Kay Elemetrics, Lincoln Park, NJ)., Results: At the group level, no general significant acoustic changes were found between the 2 conditions. The changes were highly individual and variable across the subjects. Significant changes were observed for all the subjects, most prominently for the subject with permanent nerve impairment., Conclusions: According to the results, lingual nerve impairment has effects on the production of diphthongs. A comparison between monophthongs and diphthongs showed that the alterations are more significant for the diphthongs than for other vowels indicating the more demanding, complicated, and complex manner of articulation of diphthongs.

Purpose: The purpose of the study was to evaluate the effects of the lingual nerve impairment on phonetic quality of speech by analyzing the main acoustic features of vowel sounds when the normal lingual nerve function was partly distorted by local anesthesia., Patients and Methods: The study group consisted of 7 men, whose right side lingual nerve was anesthetized with 0.8 mL of Ultracaine D-Suprarenin (Aventis Pharma Deutschland GmpH, Frankfurt am Main, Germany). The speech material analyzed consisted of 8 vowels produced in sentence context by speakers. Every utterance was repeated 10 times with and without local anesthesia. After recording, the speech samples were analyzed with a computerized speech laboratory. In addition, the vowels of 1 man with permanent nerve impairment were studied., Results: The results show that the deprived function of the tongue after lingual nerve impairment had various effects on vowel quality for every subject. The main acoustic determinants of different vowels, the lowest vocal tract resonances, changed in frequency. In addition, the total duration of vowels changed and the vowels had different fundamental frequencies. However, these effects were extremely individual and variable., Conclusions: According to the results of acoustic analysis, the distortion of lingual nerve function has effects on vowel production. Some of these changes were so extensive that they also could be perceptually detectable. Lingual nerve impairment seems to have potential to change speech production., (Copyright 2002 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 60:647-652, 2002)

Background: This is a prospective study of patients referred to a tertiary care center with permanent alteration in sensation of the inferior alveolar nerves, lingual nerves or both that could have resulted only from an inferior alveolar nerve block., Methods: Working with a subject pool of 83 patients, the researchers outlined and photographed the area of altered sensation on each patient, tested it with von Frey's hairs and two-point discrimination and tested temperature sensation and direction sense., Results: Among a study population of 55 women and 28 men with a mean age of 41.2 years, the lingual nerve was affected in 79 percent of patients and the inferior alveolar nerve in 21 percent of patients. In 47 patients, the causative inferior alveolar nerve block was painful when administered, but to the other 36 patients [corrected], it felt like a normal injection. Of the local anesthetic agents used, prilocaine was found to be more frequently linked to cases of nerve involvement in this study., Discussion: Occasionally, an inferior alveolar nerve block can result in permanent involvement of the inferior alveolar nerve, lingual nerve or both. The incidence and exact mechanism of involvement still are unknown. By extrapolation from this study, an incidence of anywhere between 1:26,762 and 1:160,571 inferior alveolar nerve blocks can be surmised to result in this complication. A difference in referral rates for male and female patients is difficult to explain. The 34 percent [corrected] incidence of dysesthesia in the patients in this study is of concern., Conclusion: Permanent nerve involvement after receiving an inferior alveolar nerve block is a documented but very rare complication of the inferior alveolar nerve block, and the exact mechanism involved is still unknown., Clinical Implications: Permanent nerve damage can very occasionally occur as a result of an inferior alveolar nerve block. The exact mechanism is unknown, and there is no means of prevention. Knowledge of the risks and complications of local anesthesia is essential.

Characteristics of mucosal nociceptors were investigated by recording activities from single fibers in the lingual nerve in an in vitro jaw-nerve preparation of rats. We found four subtypes of nociceptors in the medial side gingival area of the oral mucosa in the lower jaw: 11 A delta-high threshold mechanonociceptors (A delta-HTMs), 7 A delta-mechanoheat nociceptors (A delta-MHs), 21 A delta-polymodal nociceptors (A delta-POLYs) and 28 C-polymodal nociceptors (C-POLYs). Thus the majority of the nociceptors was polymodal type (ca. 73% of the recorded fibers), ca. 43% of which consisted of A delta-POLYs scarcely found in the skin but commonly found in the deep tissue, muscle or colon. In contrast to the skin, the size of the receptive field of both A delta and C polymodal types was larger than that of either A delta-HTM or A delta-MH type. The von Frey threshold of all types of mucosal nociceptor was higher than that of the skin, though their heat threshold was almost the same as that of the skin nociceptors. These results show that the mucosal nociceptors are different from the skin nociceptors in the frequency distribution of their types and certain physiological properties.

Menthol, a tangible substance present in many orally administered products, can produce a powerful influence on the perceived intensity of subsequent thermal stimulation in humans as well as the response magnitudes of thermally sensitive neurons in rats. However, there are no prior studies examining the influence of adaptation temperature on perceived intensity and/or response magnitudes of thermally sensitive neurons to subsequent menthol stimulation. We identified 32 thermally sensitive neurons that increased their discharge rate to a gradual temperature decrement beginning from 35 degrees C and dropping to 10 degrees C at 1 degree C/s. Based on their response threshold, time-to-peak, and range of sensitivity, these thermally sensitive lingual neurons were found to be divisible into two distinct groups. Group 1 neurons (n = 21) responded best to the upper cool range (34-15 degrees C) of the temperature decrement, whereas Group 2 neurons (n = 11) responded to the lower cold range (32-10 degrees C) of the temperature decrement. Our Group 1 and Group 2 neurons may be analogous to low threshold and high threshold cold receptors identified previously in primates. We also examined the responses of lingual neurons to 0%, 25%, 50% and 75% dilution's of a stock menthol concentration (1.28 mM) at 25 and 35 degrees C adaptation temperatures. Menthol responses across all concentrations were far larger after adaptation to 35 degrees C compared to 25 degrees C. Furthermore, only during 35 degrees C adaptation did responses to menthol stimulation persist during the ensuing 20 s after menthol off-set and water on-set.(ABSTRACT TRUNCATED AT 250 WORDS)

1. A subpopulation of lingual nerve (LN) fibers surround and/or terminate in taste buds in fungiform papillae. One possible function of these fibers is to modulate chorda tympani fiber (CT) or taste responses. To test this hypothesis, the rat LN was stimulated electrically at various voltages (to 20 V), and single- and multiunit CT responses to water-0.1 M NaCl cycles were recorded before, during, and after LN stimulation. 2. When a thermally controlled water-0.1 M NaCl stimulus cycle was applied onto the tongue's surface, the surface temperature remained constant, independent of the stimulation voltage. In the absence of a liquid stimulus, the tongue's surface temperature increased approximately 4 degrees C upon LN stimulation for voltages > or = 5 V. This temperature increase, caused by vasodilation by way of the axon reflex flare mechanism, was taken as evidence that LN stimulation induces peptide release. 3. Comparison of CT activity before LN stimulation with the activity either during or after stimulation revealed statistically significant changes in CT activity. During LN stimulation the CT activity decreased. After LN stimulation, the variability in amount of CT activity increased. 4. In rats treated postnatally with subcutaneous injections of capsaicin to reduce or eliminate polymodal nociceptors, LN stimulation did not produce increases in the tongue's surface temperature or changes in CT activity. 5. Changes in CT activity could be detected seconds after LN stimulation, suggesting that the intragemmal and/or perigemmal LN fibers modulate CT activity. 6. The physiological implications of this study suggest that CT responses to salt can be modulated by endogenous compounds (probably peptides), eating foods that activate LN responses (e.g., foods that are very acidic or contain capsaicin) may modulate taste responses, and peri- and intragemmal fibers should be considered an integral part of the taste receptor system.

The aim of this study was to investigate the amount of damage to the lingual nerve by mandibular block anaesthesia alone. For this purpose the records of 12,104 patients in whom mandibular block anaesthesia was administered without any type of surgery were reviewed. The reason for treatment in those patients was, in 72.4% fillings and crown preparations, in 27.13% periodontal procedures and in 0.30% other treatment. The records showed a lingual sensory disturbance in 18 out of 12,104 patients (0.15%). In 17 out of these 18 patients the tongue sensation recovered after a period of 6 months. Only in one patient (0.008%) was there a slight sensory diminution of the tongue, even after one year.

Electrophysiological recordings of the summated response of the chorda tympani nerve to menthol stimulation of the tongue were obtained from 15 adult Sprague-Dawley rats. The chorda tympani nerve response to menthol was of short duration, ending within 2.5 s after stimulus onset, leaving the receptors in a state of insensitivity to subsequent menthol stimulation. Rinse durations with deionized-distilled water up to 10 min failed to bring the receptors back to their original prestimulus state. Although stimulation with menthol prevented taste receptors from responding to subsequent presentations of menthol, the chorda tympani nerve would respond normally to NaCl, NH4Cl, KCl, sodium acetate, glucose, citric acid, and quinine-HCl solutions. Prior stimulation with one of these taste solutions resulted in the recovery of the menthol response. The magnitude of the recovered menthol response depended on the magnitude of the phasic response elicited by the preceding taste stimulus. A general explanation involving possible reception and transduction mechanisms was offered to account for menthol's unexpected stimulatory effects on the chorda tympani nerve.

The purpose of this study was to measure the degree of anesthesia obtained with 4% prilocaine and 3% mepivacaine compared with 2% lidocaine (1:100,000 epinephrine) for inferior alveolar nerve block. Using a repeated measures design, 30 subjects randomly received an inferior alveolar injection using masked cartridges of each solution at three successive appointments. The first molar, first premolar, lateral incisor, and contralateral canine (control) were blindly tested with an Analytic Technology pulp tester at 3-min cycles for 50 min. Anesthetic success was defined as no subject response to the maximum output of the pulp tester (80 reading) within 16 min and maintenance of this reading for 50 min. Although subjects felt numb subjectively, anesthetic success as defined here occurred in 43 to 63% of the molars, in 53 to 67% of the premolars, and in 30 to 37% of the lateral incisors. No statistically significant differences in onset, success, or failure were found among the solutions. We conclude that the three preparations are equivalent for an inferior alveolar nerve block of 50-min duration.

The authors consider mandibular infiltration as a possible alternative to mandibular block anesthesia in young children. The study sample comprised eighteen children ages six to nine years old who required bilateral identical treatment on primary mandibular molars. A random number table was used to determine which side of the mouth was to receive the block or the infiltration technique and a coin toss determined which would be administered first: A short 27 gauge needle was used to inject a 2 percent lidocaine solution with 1:100,000 epinephrine, in both techniques. The paired t-test indicated no significant difference between the two techniques for any of the factors evaluated.

Neurosensory disturbances of the third branch of the trigeminal nerve occur in rare cases without any operative treatment near the nerve involved. The most frequently affected nerve branches are the inferior alveolar nerve and the lingual nerve. We examined the problem of intraneural injection of local-anaesthetic solutions in an experimental study on animals. After intraneural injection of Articain (4%)-solution in the ischiadic nerve of Wistar rats and the lingual nerve of cats no toxic lesions were observed. It can be assumed that neurosensory disturbances caused by intraneural local-anaesthetic injection are the result of intraneural haematomas with consecutive fibrosis.