Lingual Nerve Research Articles

Rare case of Lingual Nerve Schwannoma Presenting as Submandibular Area Swelling with Parapharyngeal Extension.

Schwannoma is a rare benign encapsulated nerve sheath tumor which originates from Schwann cells. Generally, schwannoma arising from lingual nerve involves the oral tongue and tongue base in the oral cavity. We report a rare case of lingual nerve schwannoma in a 16-year-old girl with complaint of right-side submandibular swelling for last 4-5 years. A diagnosis was established based on computed tomography (CT scan) and fine needle aspiration cytology (FNAC). CT scan showed tumor involving right submandibular region and superiorly reaching up to parapharyngeal space without any intraoral swelling. She underwent excision under general anesthesia (transcervical approach) without any complication. Per operatively, the tumor was found eccentrically placed with relation to the lingual nerve and lingual nerve fibers were splayed over the tumor. The final histopathological results confirmed the diagnosis of schwannoma.

Assessment of the Impact of Different Surgical Techniques on Nerve Function and Sensation after Maxillofacial Surgery.

One potential long-term side effect of surgery in the oral and maxillofacial region is neurosensory impairment. Due to their physical proximity to the surgical location, the lingual nerve (LN) and inferior alveolar nerve (IAN), two sensory segments of the trigeminal nerve, are always susceptible to damage during third molar extraction. Assessment of the impact of different surgical techniques on nerve function and sensation after maxillofacial surgery. There was retrieval of information from medical records of study participants regarding the presence of symptoms like paresthesia, numbness, loss of sensation in lower lip, difficulty in movement of tongue, and all other findings observed after 7 days of surgical procedures. Clinically neurosensory examinations were utilized to assess nerve damage. Pinprick testing and the two-point discrimination test were used. Seven male patients were found to have damage to LN while nine males suffered damage to trigeminal nerve. 12 female patients were found to have damage to LN while 16 females suffered damage to trigeminal nerve. In total 19 patients suffered damage to LN while 25 patients suffered damage to trigeminal nerve. The incidence of LN damage was 9.5%, and the incidence of trigeminal nerve damage was 12.5%.

Pharmacologic management of trigeminal nerve injury after endodontic treatment: A retrospective analysis.

Trigeminal nerve injury following endodontic treatment, leading to unpleasant sensations or partial sensory loss in the face or oral mucosa, is uncommon but significant when it occurs. This study analysed the pharmacological management of trigeminal nerve injuries (TNI) in a university-based hospital. We conducted a retrospective analysis of 47 patients who visited the Department of Orofacial Pain and Oral Medicine at Yonsei University Dental Hospital, Seoul, Korea, after TNI following endodontic procedures in primary clinics. Both objective tests and subjective evaluations, assessed the extent and duration of sensory injury during the initial visit. The patient's initial symptoms, presumed cause of TNI, referral delay (time interval between TNI and the first visit to our clinic), and medications were analysed to determine whether these factors affected the outcomes. Most patients with TNI experienced dysesthesia with hypoesthesia (70.2%). The mandibular molars were predominantly affected (72.3%), with the inferior alveolar nerve (IAN), lingual nerve (LN), both IAN and LN, and maxillary nerve compromised in 83.0, 12.8, 2.1, and 2.1% of cases, respectively. Causes of TNI included local anaesthesia (29.8%), overfilling/over-instrumentation (25.5%), endodontic surgery (17.0%), and unknown factors (27.7%). A shorter referral delay was associated with better outcomes, with an average delay of 8.6 weeks for symptom improvement compared with 44.1 weeks for no change. The medication regimens included steroids, NSAIDs, topical lidocaine, vitamin B complex, Adenosine Triphosphate (ATP), antiepileptics, antidepressants, and opioids administered alone or in combination, with a mean duration of 20.7 weeks. 53.2% of the patients reported improvement in their symptoms, 27.7% experienced no significant change, and 19.1% had unknown outcomes. Swift referral to an orofacial pain specialist is recommended for effective recovery in cases of TNI arising from endodontic treatment.

Surgical retrieval of displaced mandibular third molars: A five-year experience with 16 cases

BACKGROUNDThis study aimed to report the surgical retrieval of iatrogenic displaced mandibular third molars using Computed Tomography CT and Cone Beam Computed Tomography CBCT as pre-surgical diagnostic imaging. MethodsSixteen patients were referred to the Oral and Maxillofacial Department, Faculty of Dentistry, XXXXX University for surgical retrieval of displaced third molars. Patients consented and thorough clinical assessment and radiographic examinations were done using either CT or CBCT scans before the standard surgical procedure to retrieve the displaced teeth. It was intended for all patients to have their displaced teeth or root fragments retrieved using an intra-oral approach while under general anesthesia. Results7 (43.75%) third mandibular left molars/root fragments and 9 (56.25 %) third mandibular right molars/root fragments were retrieved. There was no statistically significant difference regarding swelling between the two CT and CBCT groups (P> 0.05). One patient in the CT group and three patients in the CBCT group experienced lingual nerve paresthesia which was resolved after three months. ConclusionsCT and CBCT scans are crucial diagnostic tools for pre-surgical evaluation and planning for the displaced mandibular third molars. CT provides clearer images and enables easy pre-surgical assessment.

Neurotized profunda artery perforator flap for subtotal tongue reconstruction – Prospective case series

BackgroundTotal or subtotal glossectomy defects cause significant functional deficits in swallowing and speech and subsequently impair patients’ quality of life. Recently, the profunda artery perforator (PAP) flap has emerged as a potential alternative for reconstructing extensive glossectomy defects. While previous studies assessing recovery of neurotized ALT flaps in head and neck reconstruction reported superior sensory recovery, improved swallow function, and improved overall patient satisfaction in patients with neurotized flaps vs. non-neurotized ALT flap reconstruction, PAP flap neurotization has not been described and systematically assessed in head and neck patients. MethodsSix patients underwent subtotal tongue reconstruction with neurotized PAP flaps at the authors’ institution from May 2022 until August 2023. A branch of the posterior femoral cutaneous nerve of the PAP flap was coaptated to the lingual nerve. Two-point discrimination, Semmes-Weinstein monofilament, pain, and temperature assessments were conducted at 3, 6, and 12 months postoperatively on the neo-tongue. The MD Anderson speech and deglutition scales and the EORTC-QLQ-H&N35 were used to record functional outcomes and QOL. ResultsMean age was 69±4 years and mean BMI was 25±7kg/m2. Neo-tongue median two-point discrimination at the tip improved from >10mm at 3 months to 6mm at 12 months. All patients had protective pain and temperature perception at the neo-tongue tip at 6-month follow-up. Speech and swallowing function were similar at 12 month follow-up compared with data on neurotized ALT flaps from literature. No neuropathic pain was reported at the donor site at 6-month follow-up. ConclusionsThis is the first case series of PAP flap neurotization in head and neck patients, suggesting potential functional advantages with minimal donor site morbidity. Level of evidenceV Case Series

Comparative analysis of approaches to the Wharton's duct during surgery of the submandibular gland: A retrospective case-control study.

We investigated complications and recurrence rates after surgical techniques for sialolith removal with intact and resected Wharton's duct of the submandibular gland. The retrospective case-control analysis of a series analysed 271 surgical operations (2003-2022) for sialolithiasis performed at a hospital department of Otolaryngology-Head and Neck Surgery. The study compared two approaches: (1) pure endoscopic technique or pinpoint stone removal with Wharton's duct left intact and (2) transoral duct dissection or pinpoint stone removal technique, after which the duct was shortened. While choosing the surgical option, the size of the stone, the location of the stone, and the presence of multiple stones were taken into account. The rates of complications (lingual nerve paraesthesia, duct stenosis, drooling, and sialoadenitis), the incidence of foreign bodies, and the rate of recurrence during follow-up of ≥18 months were compared. 323 sialoliths were removed from 271 patients. Of these 323 calculi, 150 were removed by the first approach and 173 by the second approach. The calculi varied in diameter from 2 to 38 mm with an average diameter of 8.2 mm. For all 271 patients, the rate of recurrence was 4.8%, but 11 recurrent cases (8.7%) appeared after the first approach surgeries and 2 cases (1.4%) after the second approach surgeries (p = .03). Other variables did not show statistically significant differences. Surgical removal of the submandibular calculi, ending with shortening of Wharton's duct, reduces the recurrence rate for sialolithiasis but does not affect the rate of postsurgical complications.

The success rates and outcomes of mandibular third molar coronectomy: 167 cases

PurposeThe purpose of this study was to assess success rates and to report complications of coronectomy of mandibular third molars (M3M), including intra-operative failure, pain, infection, dry socket, inferior dental alveolar (IAN) and lingual nerve (LN) injuries and re-operation rates.MethodsRetrospective analysis of 167 coronectomies completed between January 2017 to December 2022 was undertaken.ResultsThe success of coronectomy was 93%. Intra-operative failure was reported to be 3.6% (n = 8). Complications accounted for pain (15%, n = 24), infection (9%, n = 15) and dry socket (3.6%, n = 6). Three patients required removal of M3M root at 3 months (n = 2) and 24 months (n = 1), accounting for 1.8% re-operation rate. A total of number of patients who suffered a nerve injury was 12; three of these were permanent (LN – 1.2%, n = 2; IAN – 0.6%, n = 1), nine were temporary (IAN – 1.2%; n = 2, LN – 2.4%; n = 4; site not specified – 1.8%, n = 3). No patients with intra-operative failure and re-operation suffered IAN or LN injury post-operatively.ConclusionCoronectomy offers a successful strategy for management of high risk M3M. The treatment outcomes can be improved with careful case selection and adjusting surgical technique, including assessment of root morphology, incomplete crown sectioning technique and avoidance of lingual retraction. Reporting of coronectomy success as a factor of surgical outcome, presence or absence of permanent IAN injury, persistent symptoms or any other long-standing complications (such as LN injury), and the need for re-operation accounting for root migration status may be a useful tool to measure coronectomy outcomes.

ANATOMICAL VARIABILITY OF THE SEGMENTS OF THE INFERIOR ALVEOLAR NERVE IN THE PEOPLE OF SECOND PERIOD OF MATURE AND OLDER AGE

To avoid complications of bicortical implantation, great importance is attached to the study of individual morphological features of the mandible and its structures, in particular, the anatomical variability of the inferior alveolar nerve (IAN) and mandibular canal. The purpose of the study was to fi nd out the peculiarities of the structure, topography and individual anatomical variability of the IAN in persons of the second period of maturity and older age. Cone-beam computer tomography of 54 people of both sexes aged 45-65 years with three- dimensional reconstruction, morphometry and statistical analysis was studied. On the basis of our own research on the topographical and anatomical features of the IAN and its syntopy with the mandible, in particular, with the mandibular canal, we propose to distinguish 4 of its divisions: extra- canal – from the place of formation to the entrance to the mandibular canal; intracanal – from the mandibular foramen to the mental foramen; mental – after exiting the mandibular canal; incisive – after the departure of the mental branch. The topographical and anatomical features and anatomical variability of the IAN were studied. In people of the second period of mature and elderly age, anatomical variability of the macroscopic structure and topography of the IAN was established, which manifested itself in high (4.0-11.0 mm) and low (22.0-33.0 mm) levels, relative to the foramen ovale its beginning and form (one or two trunks) of departure from the mandibular nerve. The largest number of nerve connections with other branches of the mandibular nerve is formed by the extracanal section of the IAN: with the auriculo-t emporal nerve (29 cases – 53.7 %), with the lingual nerve (5 cases – 9.26 %), with the nerve of the medial pterygoid muscle (3 observations – 5.56 %) and with the nerve of the lateral pterygoid muscle (2 specimens – 3.7 %). A diff erent level of departure of the nerve to mylohyoid from the extracanal section of the IAN was established: high (5.0-7.0 mm) and low (27.0-31.0 mm). Anatomical variability of the intracanal part of the IAN was manifested by structural variants: a single trunk (43 cases, 79.6 %), rarely – two trunks (11 observations, 20.4 %) and very rarely – the lower dental plexus (6 specimens, 11,11 %). The proximity of the roots of the 7th and 8th teeth to the IAN can be the cause of severe pain in the pathology of these teeth and cause nerve damage during their removal. Nerve connections occur between the right and left incisive nerves, the knowledge of which is an important practical value for performing anesthesia of the front row of teeth. The number of branches to the teeth, interalveolar septa and gingiva from the IAN signifi cantly decreases with age and with a violation of the integrity of the dentition.

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.

Risk factor analysis for perioperative complications in impacted third molar surgery - a single center experience.

The surgical removal of impacted third molars is usually carried out by an oral/maxillofacial surgeon. Two specific risks of surgical removal of impacted third molars are oroantral communication (OAC) when extracting ​​upper third molars and hypesthesia of the inferior alveolar nerve (IAN) ​​when extracting lower third molars. The aim of this study is to determine the distribution of complications in deeply impacted third molar surgery, to identify specific risk factors influencing the most common perioperative (OAC, IAN hypesthesia) and to compare these results with other studies. The clinical findings, digital panoramic radiographs, intra- and postoperative data of 80 patients with a total of 232 impacted third molars that had been subjected for tooth extraction, from December 2022 and August 2023, were collected and analyzed. Perioperative complications (IAN hypesthesia, OAC, hypesthesia lingual nerve, postoperative bleeding, postoperative infection) were identified. A risk analysis for OAC and IAN hypesthesia was performed regarding perioperative data. Overall, the rate of OAC for the right upper third molar was 12.8% and for the left upper third molar 15.6%. The complication rates regarding transient hypesthesia were 8.1% for the left IAN and 7.3% for the right IAN. The distance to maxillary sinus, the depth score according to Pell and Gregory, the bone coverage score, the operation time, the tooth's angulation and the type of surgeon (oral surgeon, DMD) were identified as significant risk factors for the occurrence of OAC. The minimum distance to IAN, the bone coverage score, the total operation time and the operation by an oral surgeon (DMD) were identified as significant risk factors for hypesthesia of the IAN. Next to the risk factors from above, the present study is one of the first showing that patients who were primarily operated on by an oral surgeon (DMD) and not a maxillofacial surgeon (MD, DMD) showed higher rates of OAC and IAN hypesthesia in impacted third molar extraction. The results of this study can serve as a baseline for further studies to investigate complication patterns in impacted third molar surgery.

Flipped classroom teaching model with video instruction improves skills in local anesthesia training

Local anesthesia (LA) training is an essential clinical skill in dental education. However, the traditional teaching method of student-to-student injection has ethical concerns. This study investigated whether a flipped classroom (FC) teaching model with instructional videos improves students' skills in administering LA. Fourth-year dental students in 2017 (traditional teaching, n=70) and 2018 (FC model, n=79) were assessed for their ability to perform an inferior alveolar nerve block and lingual nerve block. The FC group watched pre-recorded videos prior to a hands-on training session. Skills were evaluated using a 24-item checklist converted to letter grades. Perceptions of the FC approach were also surveyed. The FC group showed statistically significantly higher final grades than the traditional teaching group (P<0.05). Most FC students agreed that the videos improved clarity and learning objectives. The FC teaching model with procedural video instruction improved skills and confidence in administering LA over traditional teaching methods. Videos can be a beneficial supplement in pre-clinical dental training.

Lingual Taste Nerve Transection Alters Food Selection, Relative Macronutrient Intake, and Meal Patterns in Rats Consuming a Cafeteria Diet without Changing Total Energy Intake.

The control of ingestive behavior is complex and involves input from many different sources, including the gustatory system. Signals transmitted via the taste nerves trigger responses that promote or discourage ingestion. The lingual taste nerves innervate 70% of taste buds, yet their role in the control of food selection and intake remarkably remains relatively underinvestigated. Here we used our custom five-item Food Choice Monitor to compare postsurgical behavioral responses to chow and a five-choice cafeteria diet (CAF) between male rats that had sham surgery (SHAM) or histologically verified transection of the chorda tympani and glossopharyngeal nerves (2NX). Compared with SHAM rats, 2NX rats ate significantly more of the high-fat CAF foods. The altered food choices led to dramatically increased fat intake and substantially reduced carbohydrate intake by 2NX vs SHAM rats. Furthermore, whether offered chow or CAF, 2NX rats ate fewer, larger meals each day. Eating rates implied that, compared with SHAM, 2NX rats were equally motivated to consume CAF but less motivated to eat chow. Even with these differences, energy intake and weight gain trajectories remained similar between SHAM and 2NX rats. Although some rats experienced CAF before surgery, contrary to our expectations, the effects of prior CAF experience on postsurgical eating were minimal. In conclusion, although total energy intake was unaffected, our results clearly indicate that information from one or both lingual taste nerves has a critical role in food selection, regulation of macronutrient intake, and meal termination but not long-term energy balance.

Distribution of alpha-synuclein in rat salivary glands.

Expression of alpha-synuclein (Syn), a presynaptic neuronal protein, was immunohistochemically examined in intact rat submandibular, sublingual, and lingual glands. The submandibular gland contained abundant periductal Syn-immunoreactive (-ir) nerve fibers. Abundant Syn-ir varicosities were present in acini of the sublingual and serous lingual glands. By confocal laser scanning microscopy, Syn-ir nerve fibers around smooth muscle actin (SMA)-ir cells alone were infrequent; however, those around aquaporin-5 (AQP5)-ir cells alone and both SMA- and AQP5-ir cells were abundant in the sublingual and serous lingual glands. SMA-ir cells were occasionally immunoreactive for toll-like receptor 4, a Syn receptor. Syn-ir nerve fibers contained tyrosine hydroxylase (TH) in the submandibular gland and choline acetyltransferase (ChAT) in all examined salivary glands. In the superior cervical (SCG), submandibular, and intralingual ganglia, sympathetic and parasympathetic neurons co-expressed Syn with TH and ChAT, respectively. SCG neurons innervating the submandibular gland contained mostly Syn. In the thoracic spinal cord, 14.7% of ChAT-ir preganglionic sympathetic neurons co-expressed Syn. In the superior salivatory nucleus, preganglionic parasympathetic neurons projecting to the lingual nerve co-expressed Syn and ChAT. The present findings indicate that released Syn acts on myoepithelial cells. Syn in pre- and post-ganglionic neurons may regulate neurotransmitter release and salivary volume and composition.

Evaluation of postoperative complications after removal of mandibular third molar by conventional bur technique and lingual split technique

ABSTRACT Aim: The objective of this study was to evaluate the effect and safety including postoperative outcomes in the extraction of impacted mandibular third molar by conventional bur technique and lingual split technique. Methods, Selection Criteria, and Search Strategy: A total of 40 healthy individuals, both male and female, aged from 18 to 40 years, underwent surgical removal of impacted mandibular third molars under local anesthesia in a single session. An intensive electronic search was conducted on Google, PubMed, Scopus, Embase, Directory of Open Access Journals, Ovid Medline, and Cochrane Central online databases from their respective inception dates to November 2020. Initially, the search criteria included the terms: ((mandibular OR lower) AND (third molar OR wisdom) AND lingual split). The following outcomes were investigated: pain, swelling, trismus, and dry socket on the first day before surgery, the second (post 24 h), and on the seventh day. Results and Observations: The present retrospective comparative study evaluates the postoperative complications after the removal of the third molar. A total of 40 subjects of either sex were randomized to be treated either with the conventional bur technique (Group A) or the lingual split technique (Group B). The ages of Groups A and B ranged from 19 to 40 years and from 19 to 42 years, respectively, with a mean ± SD of 26.20 ± 6.01 and 27.15 ± 6.21 years, respectively. The mean age of Group B was slightly higher than Group A. Comparing the mean age of the two groups, t-test revealed similar (P &gt; 0.05) age between the two groups (26.20 ± 6.01 vs. 27.15 ± 6.21, t = 0.49; P = 0.626). The subjects in both groups were age-matched, suggesting that age may have had minimal influence on the outcome measures (swelling, trismus, and pain). Conclusion: In the realm of mandibular third molar (M3) extraction, it is acknowledged that this surgical procedure can present challenges, and there exists a diversity of professional approaches between dentists and oral surgeons. Prior to determining a treatment course for each M3, it is imperative to possess a comprehensive understanding of the pertinent anatomical structures, including the inferior dental and lingual nerves. Additionally, a thorough clinical assessment and the utilization of radiographic imaging are essential for carefully evaluating each case and balancing the advantages and disadvantages of various treatment plans. Timely removal of the third molar (tooth M3) can significantly reduce the adverse complications associated with delayed extraction.

Особливості ураження трійчастого нерва при стоматологічних захворюваннях: надання невідкладної допомоги

Summary. Usually, the clinical basis of neurostomatological diseases is the lesion of various parts of the nervous system that provide innervation of the oral cavity and face. The main nerves whose damage leads to the development of neurostomatological diseases are the trigeminal, facial, intermediate, lingual, vagus and hyoid nerves. Among them, the trigeminal nerve system is most often affected. The causes can be odontogenic diseases such as pathological processes of the dentition and ineffective or incorrect methods of their treatment (traumatic complex tooth extraction, including the presence of bone fragments, root remnants in the socket, pulpitis and periodontitis, galvanisation phenomena when using various methods for filling and prosthetics, poorly made dentures, gingivitis, etc.) In the lecture, we tried to highlight the lesions of the trigeminal nerve system in dental diseases, emergency care, treatment and rehabilitation. Key words: trigeminal neuralgia, dental diseases, emergency care.

Unusual Presentation of Trigeminal Neuralgia and its Surgical Management

Trigeminal neuralgia (TN) is a debilitating neuropathic condition characterized by excruciating, lancinating pain attacks. The standard first-line treatment of TN is carbamazepine medication, but some patients do not experience relief from this drug. For cases that do not respond to medication, surgical procedures that cut or remove portions of the peripheral nerves, such as the inferior alveolar and mental nerves, can be attempted. However, these neurectomysurgeries often have high rates of severe facial pain recurring over time. A 40-year-old man suffered from chronic, debilitating trigeminal neuralgia. He underwent multiple tooth extractions and took carbamazepine, but neither provided improvement in his agonizing facial pain. He then had surgical neurectomies of the mental and inferior alveolar nerves, which provided only partial pain relief. The patient was not relieved, so he underwent a surgical neurectomy of the lingual nerve. This third procedure successfully provided a significant reduction in his trigeminal neuralgia pain. Lingual neurectomy emerges as a potentially definitive treatment modality for trigeminal neuralgia refractory to medication or alternative neurectomy procedures. This minimally invasive surgical approach offers a valuable option for patients seeking sustained pain relief, particularly those who are not suitable candidates for or desire to avoid, more extensive or resource-intensive interventions.

Coronectomy? A case report following coronectomy of a ‘high-risk’ mandibular third molar

Background The surgical removal of mandibular third molar (M3M) is a common procedure performed by oral and maxillofacial surgeons, oral surgeons, and general dental practitioners. Apart from risks such as pain, swelling, bruising, bleeding, trismus, alveolar osteitis, post-op infection, and damage to adjacent structures which are common to all surgical extractions, M3M removal includes the risk of permanent or temporary damage to the inferior alveolar nerve (IAN) or the lingual nerve. IAN damage can significantly impact the quality of life due to altered sensation of the lip and chin area. As such, the alternative surgical option of coronectomy, which is the sectioning of the crown from the tooth and deliberate retention of the roots, can be offered to high-risk cases to avoid IAN damage. Case presentation 36-year-old female was diagnosed with recurrent pericoronitis of her left M3M. Her left M3M was partially erupted and horizontally impacted with bulbous roots that were in close proximity to the IAN. Due to a higher risk of IAN damage, she underwent a coronectomy procedure of her left M3M instead of a complete removal. She experienced typical post-operative pain and swelling but no other complications such as altered nerve sensation were reported. The surgical site was healed with full mucosal coverage after 12 weeks. Conclusion Coronectomy provides a viable alternative surgical option to removal for mandibular third molars that are at high risk of IAN damage. This is due to the significant reduction of risk of IAN damage and low incidence of failure.

Site-specific autonomic vasomotor responses and their interactions in rat gingiva

Blood flow in the gingiva, comprising the interdental papilla as well as attached and marginal gingiva, is important for maintaining of gingival function and is modulated by risk factors such as stress that may lead to periodontal disease. Marked blood flow changes mediated by the autonomic (parasympathetic and sympathetic) nervous system may be essential for gingival hemodynamics. However, differences in autonomic vasomotor responses and their functional significance in different parts of the gingiva are unclear. We examined the differences in autonomic vasomotor responses and their interactions in the gingiva of anesthetized rats. Parasympathetic vasodilation evoked by the trigeminal (lingual nerve)-mediated reflex elicited frequency-dependent blood flow increases in gingivae, with the increases being greatest in the interdental papilla. Parasympathetic blood flow increases were significantly reduced by intravenous administration of the atropine and VIP antagonist. The blood flow increase evoked by acetylcholine administration was higher in the interdental papilla than in the attached gingiva, whereas that evoked by VIP agonist administration was greater in the attached gingiva than in the interdental papilla. Activation of the cervical sympathetic nerves decreased gingival blood flow and inhibited parasympathetically induced blood flow increases. Our results suggest that trigeminal-parasympathetic reflex vasodilation 1) is more involved in the regulation of blood flow in the interdental papilla than in the other parts of the gingiva, 2) is mediated by cholinergic (interdental papilla) and VIPergic systems (attached gingiva), and 3) is inhibited by excess sympathetic activity. These results suggest a role in the etiology of periodontal diseases during mental stress.

Accuracy of MR neurography as a diagnostic tool in detecting injuries to the lingual and inferior alveolar nerve in patients with iatrogenic post-traumatic trigeminal neuropathy

ObjectivesMR neurography has the ability to detect and depict peripheral nerve injuries. This study evaluated the potential of MR neurography in the diagnosis of post-traumatic trigeminal neuropathy.MethodsForty-one participants prospectively underwent MR neurography of the lingual and inferior alveolar nerves using a 3D TSE STIR black-blood sequence. Two blinded and independent observers recorded the following information for each nerve of interest: presence of injury, nerve thickness, nerve signal intensity, MR neurography Sunderland class, and signal gap. Afterwards, the apparent nerve-muscle contrast-to-noise ratio and apparent signal-to-noise ratio were calculated. Clinical data (neurosensory testing score and clinical Sunderland class) was extracted retrospectively from the medical records of patients diagnosed with post-traumatic trigeminal neuropathy.ResultsCompared to neurosensory testing, MR neurography had a sensitivity of 38.2% and specificity of 93.5% detecting nerve injuries. When differentiated according to clinical Sunderland class, sensitivity was 19.1% in the presence of a low class injury (I to III) and improved to 83.3% in the presence of a high class (IV to V). Specificity remained unchanged. The area under the curve using the apparent nerve-muscle contrast-to-noise ratio, apparent signal-to-noise ratio, and nerve thickness to predict the presence of an injury was 0.78 (p < .05). Signal intensities and nerve diameter increased in injured nerves (p < .05). Clinical and MR neurography Sunderland scores positively correlated (correlation coefficient = 0.53; p = .005).ConclusionsThis study shows that MR neurography can accurately differentiate between injured and healthy nerves, especially in the presence of a more severe nerve injury.Clinical relevance statementMR neurography is not only able to detect trigeminal nerve injuries, but it can also provide information about the anatomical specifications of the injury, which is not possible with clinical neurosensory testing. This makes MR neurography an added value in the management of post-traumatic trigeminal neuropathy.Key Points• The current diagnosis of post-traumatic trigeminal neuropathy is mainly based on clinical examination.• MR neurography is able to visualize and stratify peripheral trigeminal nerve injuries.• MR neurography contributes to the diagnostic process as well as to further decision-making.

Lingual Nerve Injury During Mandibular Third Molar Extraction: A Review

Lingual Nerve Injury During Mandibular Third Molar Extraction: A Review