Nasopalatine Research Articles

The prognosis of nasopalatine nerve severance during dental surgical procedures in children

The prognosis of nasopalatine nerve severance during dental surgical procedures in children

COMPARISON OF PAIN LEVELS BETWEEN THE CONVENTIONAL AND THE COMPUTERIZED ANESTHETIC INJECTION WITH MORPHEUS® FOR THE NASOPALATINE NERVE BLOCK: A DOUBLE-BLIND RANDOMIZED CLINICAL TRIAL

Objective: To compare pain levels between the conventional injection and the Morpheus® device for the nasopalatine nerve block concerning the puncture, needle introduction, and local anesthetic (LA) deposition. Methods: A crossover, double-blind, randomized clinical trial was carried out involving 32 participants. Group I comprised the conventional syringe (control group), while Group II comprised the Morpheus® device (experimental group). The study was developed in two sessions, two weeks apart. The pain was assessed using a 100-mm Visual Analog Scale (VAS). The intragroup analyses were performed using Friedman’s test and Durbin-Conover's post hoc test. The Wilcoxon test was used for intergroup analyses. The significance level was set at p < 0.05. Results: Intragroup analyses showed statistical differences within both groups (Group I, p < 0.001; Group II, p = 0.003). All the evaluated moments of both injection techniques differed statistically, except between the needle introduction and LA deposition within Group II (p = 0.526). In the intergroup analyses, participants of Group I presented higher pain levels, experiencing the highest pain at the LA deposition moment (median 58; 46 - 62). Pain levels were statistically significant between all the corresponding moments of the groups (p < 0.001). Conclusion: Computerized injection with the Morpheus® can be effectively employed to increase comfort during anesthetic injections and patient compliance with dental treatments.

Conservative endodontic microsurgery to protect critical anatomical structures–selective curettage: a case series

BackgroundEndodontic microsurgery has yielded highly successful outcomes in preserving teeth with persistent or recurrent cases of periapical periodontitis that could not be successfully treated by nonsurgical endodontic approaches. To avoid complications in conditions in which periapical lesions invade anatomical structures such as the nasopalatine nerve tube and mandibular canal, selective curettage has been proposed as an alternative choice of complete curettage in surgery.Case presentationThe 8 cases reported herein had undergone root canal treatment and/or retreatment but still presented with symptoms, such as recurring sinus tracts and persistent dull pain. The radiographic examination indicated a large area of radiolucency that was associated with the tooth and had invaded adjacent critical anatomical structures. The patients opted for selective curettage via endodontic microsurgery, and the lesions were histologically confirmed as periapical cysts or granulomas. The follow-up results for one year or more indicated that the affected teeth were clinically asymptomatic and exhibited complete or incomplete healing radiographically.ConclusionThis case series provides clinical evidence for the feasibility of selective curettage in endodontic microsurgery, which can avoid complications caused by damage to the adjacent critical anatomical structures.

The Impacts of Cigarette Smoking on Nerves and Oral Health

This paper effects of cigarette smoking on nerves and oral health. Smoking adversely affects the trigeminal, lingual, and nasopalatine nerves, leading to taste and smell disturbances, xerostomia, and decreased somatosensory function. Additionally, cigarette smoke contains harmful chemicals such as carbon monoxide, tar, benzene, arsenic, and formaldehyde, which contribute to the development of chronic diseases such as lung cancer, COPD, stroke, and heart disease. Smoking also impedes oral health by negatively impacting wound healing and promoting bad breath, staining, and aging. The paper underscores the critical need for smoking cessation interventions and public education campaigns to raise awareness about the deleterious effects of cigarette smoking. Overall, prioritizing smoking cessation as part of a comprehensive approach to promoting healthy nerves and oral health is paramount. Keywords: Cigarette smoking, nerves, somatos, health effects, periodontal diseases, slow response, xerostomia.

Morphological Studies to Identify the Nasopalatine and Inferior Alveolar Nerve Using a Special Head and Neck MRI Coil.

Procedures in oral and maxillofacial surgery bear a high risk of nerve damage. Three-dimensional imaging techniques can optimize surgical planning and help to spare nerves. The aim of this study was to investigate the diagnostic value of a 1.5 T magnetic resonance imaging (MRI) scanner with a dedicated dental signal amplification coil for the assessment of nerves in the oral cavity as compared with cone beam computed tomography (CBCT). Based on 6 predefined criteria, the assessability of the inferior alveolar and nasopalatine nerves in CBCT and MRI with a dedicated 4-channel dental coil were compared in 24 patients. Compared with CBCT, MRI with the dental coil showed significantly better evaluability of the inferior alveolar nerve in the sagittal and axial plane and the nasopalatine nerve in the axial plane. In the sagittal plane; however, the assessability of the nasopalatine nerve was significantly better in CBCT as compared with MRI. Yet, pertaining to overall assessability, no significant differences between modalities were found. In this pilot study, it can be reported that 1.5- T MRI with a dedicated dental coil is at least equivalent, if not superior, to CBCT in imaging nerve structures of the stomatognathic system. Preoperative, 3-dimensional images are known to simplify and refine the planning and execution of operations in maxillofacial surgery. In contrast to computed tomography and CBCT, MRI does not cause radiation exposure while enabling visualization of all relevant hard and soft tissues and, therefore, holds an advantage over well-established techniques.

The sphenopalatine vein: anatomical study of a rarely described structure.

Although in counterpart, the sphenopalatine artery (SPA), has been well described in the medical literature, the sphenopalatine vein (SPV) has received scant attention. Therefore, the present anatomical study was performed. Additionally, we discuss the variations, embryology, and clinical significance of the SPV. Adult cadaveric specimens underwent dissection of the SPV. In addition, some specimens were submitted for histological analysis of this structure. The SPV was found to drain from the sphenoidal sinus and nasal septum. Small tributaries traveled through the nasal septum with the posterior septal branches of the SPA and nasopalatine nerve. The SPA and SPV were found to travel through the sphenopalatine foramen and another tributary was found to perforate the medial plate of the pterygoid process and to connect to the pterygoid venous plexus which traveled lateral to the medial plate of the pterygoid process. The vein traveled through the posterior part of the lateral wall of the nasal cavity with the posterior lateral nasal branches of the SPA and the lateral superior posterior nasal branches of the maxillary nerve. To our knowledge, this is the first anatomical study on the SPV in humans. Data on the SPV provides an improved anatomical understanding of the vascular network of the nasal cavity. Developing a more complete picture of the nasal cavity and its venous supply might help surgeons and clinicians better manage clinical entities such as posterior epistaxis, cavernous sinus infections, and perform endoscopic surgery with fewer complications.

Evolution of the therian face through complete loss of the premaxilla.

The anatomical framework of the jawbones is highly conserved among most of the Osteichthyes, including the tetrapods. However, our recent study suggested that the premaxilla, the rostralmost upper jaw bone, was rearranged during the evolution of therian mammals, being replaced by the septomaxilla at least in the lateral part. In the present study, to understand more about the process of evolution from the ancestral upper jaw to the therian face, we re-examined the development of the therian premaxilla (incisive bone). By comparing mouse, bat, goat, and cattle fetuses, we confirmed that the therian premaxilla has dual developmental origins, the lateral body and the palatine process. This dual development is widely conserved among the therian mammals. Cell-lineage-tracing experiments using Dlx1-CreERT2 mice revealed that the palatine process arises in the ventral part of the premandibular domain, where the nasopalatine nerve distributes, whereas the lateral body develops from the maxillary prominence in the domain of the maxillary nerve. Through comparative analysis using various tetrapods, we concluded that the palatine process should not be considered part of the ancestral premaxilla. It rather corresponds to the anterior region of the vomerine bone of nonmammalian tetrapods. Thus, the present findings indicate that the true premaxilla was completely lost during the evolution of the therian mammals, resulting in the establishment of the unique therian face as an evolutionary novelty. Reconsideration of the homological framework of the cranial skeleton based on the topographical relationships of the ossification center during embryonic development is warranted.

ORAL SMALL FIBER NEUROPATHY IN LYME DISEASE: IS BOTULINUM TOXIN TYPE-A A THERAPEUTIC OPTION IN ITS MANAGEMENT?—A CASE REPORT

<h3>Objective</h3> Small fiber neuropathy (SFN) has been associated with posttreatment Lyme disease syndrome (PTLDS), a chronic widespread pain condition with an enormous impact on quality of life. SFN has been associated with hyperalgesia and allodynia, as seen in fibromyalgia. In PTLDS, peripheral and central pain mechanisms involving SFN are likely present, with neuropeptide imbalance, leading to increased nociceptive signaling. Refractory SFN cases are challenging to manage, and Botulinum toxin type-A (BTX-A) could be a treatment option with long-lasting results and fewer side effects. BTX-A analgesic effects may be related to the disruption of vesicular transport into the synapse, inhibiting local/peripheral and central release of algogenic neurotransmitters, preventing neurogenic inflammation and peripheral sensitization. <h3>Case Summary</h3> A 41-year-old woman was assessed in January 2019 at the Oral Medicine clinic for constant severe palatal pain. In January 2018 she was diagnosed and treated for Lyme disease after thorough specialist investigation. Subsequently, she was diagnosed with fibromyalgia, trigeminal neuralgia, and SFN, among other conditions related to PTLDS. Therapeutic trials with amitriptyline and pregabalin were partially palliative, but the palatal pain persisted. She correlated the pain with "swelling and inflammation." Clinical examination revealed no mucosal lesion but a mild erythema and edema on the incisal papilla, along with hyperalgesia and allodynia on the rugae; blocking of the nasopalatine nerve relieved the pain. A traumatic etiology was ruled out using an occlusal splint, and neuropathic pain (SFN) was our tentative diagnosis. Topical compounded neuropathic pain ointment was partially palliative. A trial of 30 units local BTX-A injections resulted in improvement of her symptoms. The total dose injected was increased to 50 units in subsequent sessions, at 3-month intervals. After the second session, she had a significant improvement, reporting the "best 30 days in three years." In January 2021, she confirmed the progressive improvement of her condition. <h3>Conclusions</h3> These results indicate that BTX-A may be an alternative in managing oral neuropathic pain in Lyme disease. To our knowledge this is the first report of the use of BTX-A for this condition. Further research is needed to provide evidence to these assumptions and the conception of clinical guidelines.

Сучасні хірургічні методи лікування одонтогенних кіст щелеп (огляд літератури та власні дані)

The purpose of the study was to analyze the data of modern domestic and foreign professional literature, which are devoted to new surgical methods of treatment of odontogenic cysts, to highlight the results of own clinical studies on the effectiveness of developed methods of cystectomy in jaw bones and their anesthesia. Materials and methods. Analytical and bibliosemantic methods were used in the research. The search for scientific information on medical topics for the period from 2010 to 2021 was carried out in the databases of electronic searching systems. Results and discussion. The use of standard techniques of conduction anesthesia of the trigeminal nerve is not always effective during cystectomy in the lateral parts of the mandible, due to the variability of branching of the trigeminal nerve, the possibility of additional innervation of the jaw branch from the superficial cervical plexus. Taking into account these anatomical factors, it is painless to perform a cystectomy of odontogenic cysts on the mandible. During oronasal cystectomy of odontogenic cysts that have grown into the nasal cavity it is advisable to block the nasopalatine nerve in the middle nasal passage. Modified methods of marsupialization can be used as an independent method of treatment of odontogenic cysts of large size, or be combined with radical removal of the cyst membrane. The use of ultrasound medical techniques reduces the risk of damage to adjacent soft tissues during enucleation of bone membranes in complex topographic and anatomical areas. The use of modern laser technologies and medical radiophysical equipment can increase the effectiveness of surgical treatment of odontogenic jaw cysts. The use of endovideosurgery techniques reduces the percentage of intraoperative complications. The introduction of computer spatial imaging of anatomical objects in dental practice has made it possible to develop new surgical technologies for precision-guided osteotomy and resection of the tips of the roots of masticatory teeth adjacent to the shells of radicular jaw cysts. Conclusion. In modern clinical practice, technical developments are used, which are based on the latest advances in laser optics, radio physics, bioacoustics, computer technology, which minimizes injuries during cystectomy operations, reduces the frequency of intraoperative complications. Individual-anatomical features of innervation of the maxillofacial area should be taken into account during local anesthesia, cystectomy and cystotomy operations in the jaw bones

Оптимізація місцевого знеболювання під час проведення операції радикальної гайморотомії у стоматологічних хворих

The purpose of the study was to give a clinical evaluation of the effectiveness of endonasal blockade of the nasopalatine nerve in different ways during radical maxillary sinusotomy in dental patients. Materials and methods. Clinical observations were performed in 50 patients diagnosed with chronic odontogenic maxillary sinusitis. Radical maxillary sinusotomy was performed under local potentiated anesthesia. All patients underwent anesthesia on the maxilla according to classical methods. Patients, depending on the methods of endonasal blockade of the nasopalatine nerve, were divided into two clinical groups: the main (24 people) and the comparison group (26 people). Patients of the main group underwent endonasal blockade of the nasopalatine nerve at the site of its branch from the pterygopalatine ganglion. In patients of the comparison group, the blockade of this nerve was performed before its entry into the incisal canal. The effectiveness of anesthesia was evaluated for clinical and autonomic manifestations of pain stress. Results and discussion. During the removal of polyps and pathological granulations from the mucous membrane of the maxillary sinus in patients of the main group there was no pain, no emotional-motor and autonomic manifestations of pain stress, which confirmed the effectiveness of the endonasal method of anesthesia of the nasopalatine nerve. In patients of the comparison group during similar surgical manipulations the full effect of local anesthesia was achieved in 50.0% of cases (χ2 – 8.065, р = 0.005). These were patients who had hypopneumatized or moderately pneumatized types of maxillary sinuses. The rest of the patients during the operation had emotional – motor and autonomic manifestations of pain stress during the removal of pathologically altered mucous membrane located on the medial wall of the maxillary sinus. Conclusion. Complete anesthesia of the mucous membrane, maxillary sinus, regardless of the degree of its pneumatization is achieved during the usage of endonasal blockade of the nasopalatine nerve at the site of its branch from the pterygopalatine ganglion during radical maxillary sinusotomy in dental patients. Anesthesia of the nasopalatine nerve in the lower nasal passage, before its entry into the incisal canal, allows painless surgery only in patients with hypopneumatized maxillary sinuses and in most patients with moderate pneumatization

Clinical study of age-related sensory innervation of the anterior hard palate

The present study aimed to explore the innervation of the anterior hard palatine and its relationship with individual development stage. Specifically, the effects of anesthesia on patients of different ages were observed, and neurodevelopment in the maxillofacial region was invesitgated. References that are helpful in selecting local anesthesia were provided. A total of 182 patients with mixed dentition were randomly divided into the nasopalatine nerve block and greater palatine nerve block groups. Then, 219 patients with permanent dentition were divided into an adolescent group (13-18 years old) and adult group (over 19 years old), all of whom underwent bilateral greater palatine nerve block. Palatal mucosal pain sensation was tested pre- and post-anesthesia with Von Frey hairs. Among the children with mixed dentition, bilateral greater palatine nerve block tended to result in better anesthetic effects than nasopalatine nerve block (P<0.05), except in the incisive papilla. No difference in anesthetic effect was observed between adolescents and adults (P>0.05). The bilateral greater palatine nerve block was more effective in inducing an anesthestic effect in the anterior hard palatine in mixed dentition than in permanent dentition (over 13 years old; P<0.05). The sensation of the anterior hard palatine seems mainly dominated by the greater palatine nerve until mixed dentition and gradually shifted to the nasopalatine nerve in conjunction with maxillary development and tooth replacement. Hence, the innervation of the anterior hard palatine induce a secondary development during the development of the maxilla.

OPTIMIZATION OF LOCAL ANESTHESIA OF DENTAL PATIENTS DURING CYSTECTOMIES OF RADICULAR CYSTS THAT HAVE GROWN INTO THE MAXILLARY SINUS OR NASAL CAVITY

The aim: To provide clinical evaluation of the effectiveness of anesthesia for cystectomy of radicular cysts that have grown into the maxillary si-nus or nasal cavity using different techniques of endonasal block-ade of the nasopalatine nerve. Materials and methods: Clinical observations were conducted on 52 patients of different age and sex. These patients were diagnosed with large radicular cysts (more than 3.0 cm in diameter) that had grown into the maxillary sinus (33 cases) or into the nasal cavity (19 cases). The surgical excisions of cysts (oroantral cystectomies) were performed un-der local potentiated anesthesia. Patients were divided into two clinical groups, depending on the methods used for endonasal blockade of the nasopalatine nerve: the main and the control group. Patients in the main group underwent endonasal blockade of the nasopalatine nerve at the point of its emergence from the pterygopalatine ganglion. In the control group, the neural blockade was performed at the entry of this nerve into the incisive canal. Pain sensitivity and perception in patients were studied using subjective and objective methods. The data was analyzed by means of the Pearson's chi - square tests. Results: During the enucleation of radicular cysts that grew into the inferior nasal meatus and maxillary sinus in patients of the main group there was no pain observed. There were no manifestations of pain-induced stress neither from the side of autonomic system, nor physical or emotional manifestations of pain, which confirmed the effectiveness of nasopalatine nerve anesthesia. In patients of the control group during similar operation the full effect of local anesthesia was achieved in 56.0% of cases (χ2 - 9,270, р = 0,003). The rest of the patients during cystectomies showed some signs of pain-induced stress from the side of autonomic system or in the form of physical or emotional manifestations. Conclusions: Endonasal blockade of the nasopalatine nerve at the point of its emergence from the pterygopalatine ganglion invariably provided a complete analgesia during enucleation of radicular cysts that have grown into the maxillary sinus or nasal cavity. Anesthesia of the nasopalatine nerve at its entry into the incisive canal allows pain-less cystectomy of radicular cysts that have spread to the front of the inferior nasal meatus from the front teeth.

Herpes zoster of the trigeminal nerve with multi-dermatomal involvement: a case report of an unusual presentation

BackgroundHerpes zoster, also known as shingles, results from reactivation of the varicella-zoster virus. It commonly presents with burning pain and vesicular lesions with unilateral distribution and affects the thoracic and cervical sites in up to 60 and 20% of cases, respectively. The branches of the trigeminal nerves are affected in up to 20% of cases. Multidermatomal involvement of the trigeminal nerves has been only anecdotally described in immunocompetent subjects.Case presentationA 71-year-old previously healthy male presented with grouped vesicular and impetiginized lesions with crusts on the left half of the face of two-weeks duration. The lesions first developed on the left nasal tip and progressively worsened with unilateral appearance of vesicular lesions on the left forehead, face, ala nasi, nasal vestibulum and columella, as well as on the left side of hard and soft palate. The affected edematous erythematous areas corresponded to the distribution of the left ophthalmic (V1) and maxillary (V2) branches of the trigeminal nerve, including the infraorbital and nasopalatine nerves of the maxillary branch responsible for the oral cavity involvement. Viral DNA amplification by polymerase chain reaction confirmed the presence of Varicella zoster virus. The patient was started on oral valaciclovir with rapid recovery.ConclusionsAmong immunocompetent patients, herpes zoster is considered a self-limited localized infection. Our observation provides a rare but paradigmatic example of herpes zoster with involvement of both the ophthalmic and maxillary divisions of the trigeminal nerve in an immunocompetent patient. Immunocompetence status and age-specific screening should be warranted in case of atypical involvement and according to the patient’s history, while treatment with antiviral drugs should be rapidily initiated in patients at risk.

Three-Dimensional Analysis of the Nasopalatine Canal in Dentulous and Edentulous Maxilla – A Cone-Beam Computed Tomography Study

Introduction: Dental esthetics has become an important concern today, and the patients consider the esthetic outcome to be an important factor in the anterior maxilla. Nasopalatine canal (NPC) plays an important role in making decisions regarding implant placement in the anterior maxilla. The aims of the present study were to analyze and compare the length and diameter of NPC and bone dimensions anterior to the canal in dentulous and edentulous maxilla for dental implant consideration using cone-beam computed tomography (CBCT). Materials and Methods: Sixty CBCT scans were collected retrospectively for the examination of NPC of individuals who had undergone CBCT scans for dental treatment purposes. The length of the canal and bone dimensions anterior to the canal were measured in multiplanar reformation. Results: The mean canal length was less in edentulous than dentulous patients. Moreover, the bone width anterior to the canal and bone height were also more in dentulous patients, with mean bone width being 8.518 ± 1.9 mm and bone height 7.993 ± 1.4 mm. The bone width and bone height in edentulous cases were 6.910 ± 1.44 mm and 5.183 ± 1.1 mm, respectively. Conclusion: Although there are variations in each patient, thorough knowledge of NPC and bone dimension is essential for implant placement to avoid any complication.

Is nasopalatine nerve block still mandated for the extraction of maxillary anterior teeth?

Aim This study was conducted to investigate the effectiveness of a single labial injection of 4% articaine for the extraction of maxillary anterior teeth without the need for nasopalatine supplementary injection.Materials and methods A prospective, controlled, split-mouth clinical study was performed to evaluate the clinical performance of 4% articaine as a single labial infiltration anaesthesia for the extraction of maxillary anterior teeth and to compare it with the routine method of labial injection along with a supplementary nasopalatine injection using 2% lidocaine. Statistical analyses were performed, with the statistical significance being set at 5% level.Results A total of 37 patients met the inclusion criteria, and a statistically significant difference was observed in the reported pain during injection between the single labial articaine injection and the routine labial and palatal lidocaine injections (P <0.001). The extraction of maxillary anterior teeth was possible without the need for an additional nasopalatine injection in all the study patients (n = 37). The difference between both groups was statistically non-significant in terms of the pain encountered during extraction (P = 0.22).Conclusion With the use of 4% articaine as a single labial infiltration anaesthesia, nasopalatine nerve block for the extraction of maxillary anterior teeth may become an outdated modality.

Effectiveness of the Greater Palatine Nerve Block for Anaesthetising Anterior Palate: A Prospective Study

Introduction: Local Anaesthesia (LA) is the mainstay of any routine dental extraction. Accomplishing optimum anaesthesia with least pain and anxiety to patients is a challenge. Hence, modification of technique and application of routine dental LA to enhance patient comfort is the need of the hour. In this pursuit, a prospective cohort study was carried out to evaluate the effectiveness of greater palatine nerve block as an alternative to nasopalatine nerve block in anaesthetising the anterior palatal mucosa and to achieve optimum palatal anaesthesia. Aim: The primary outcome variable is to assess the extent of the anaesthetic effect of greater palatine nerve block in maxillary anterior palatal region. Materials and Methods: A total of 100 patients scheduled for the extraction of ipsilateral anterior and posterior maxillary teeth were included in this prospective study between June 2017 to June 2019. Palatal anaesthesia for all the extractions done was achieved only with greater palatine nerve block. After an interval of five minutes, the extent of palatal anaesthesia from the posterior palatal tissue to the anterior region was evaluated for both subjective and objective symptoms. Pain on the palatal mucosa was assessed using Numerical rating scale of 0-10. Post-evaluation, depending on the proposed tooth of extraction, buccal anaesthesia was achieved with Posterior superior alveolar nerve block for posterior teeth and infraorbital nerve block for anterior teeth. Results: Of the 100 patients administered with greater palatine nerve block, it was observed that in 36 patients (36%) had effectiveness in anaesthesia till central incisor, 28 (28%) patients had effectiveness in anaesthesia till lateral incisor, 20 (20%) patients had effective in anaesthesia till the canine and 16 (16%) patients anaesthetic effects were limited to posterior teeth. Overall, 84% had varied degree of positive anterior anaesthesia with greater palatine nerve block alone. Conclusion: Greater palatine nerve block was effective in providing anaesthesia to the posterior region till the premolars, with the extended complete anaesthesia in the anterior region with similar action as the nasopalatine nerve block administered to anaesthetise the anterior palate for extraction of the anterior teeth.

Study the Effect of Neurectomy of Nasopalatine Nerve on Sensation of Anterior Palate

Study the Effect of Neurectomy of Nasopalatine Nerve on Sensation of Anterior Palate

Central Terminals of Trigeminal Nerves that Innervate the Nose and Nasal Passages Colocalize with Medullary Dorsal Horn Neurons Activated during Voluntary Diving in Rats

Underwater submersion in mammals initiates the diving response, an autonomic cardiorespiratory reflex that includes apnea, a parasympathetically‐mediated bradycardia, and a sympathetically‐mediated increase in total peripheral resistance. The initial synapse of this reflex occurs within the ventral medullary dorsal horn (MDH) of the spinal trigeminal nucleus caudalis. The anterior ethmoidal and nasopalatine nerves, trigeminal nerves that innervate the internal nasal passages, also send their central terminations to the ventral MDH. The objective of this research was to detect colocalization of secondary MDH neurons activated by voluntary diving with the central terminations of the trigeminal nerves innervating the internal nasal passages. MDH activated neurons were identified by Fos protein production, while central terminals of the trigeminal nerves were located by the transganglionic tracer Wheat Germ Agglutinin (WGA). Sprague‐Dawley rats (N=12) were trained to voluntarily dive through a 5 m underwater Plexiglas maze. After training, 6 rats then received WGA injections into the anterior ethmoidal nerve, while 6 rats received WGA injections into the nasopalatine nerve. Four days post‐WGA injection, 3 rats from each nerve injection group performed 12 dive trials over 1 hour to activate brainstem neurons and initiate Fos production; 3 rats from each nerve injection group were non‐diving controls. Brainstem tissue from all rats was immunohistochemically processed to visualize both Fos and WGA, and was inspected using a Nikon C1 confocal microscope and Nikon Eclipse Ti2 inverted fluorescent microscope. Results indicate repetitive voluntary diving increases the number of Fos‐positive neurons within the ventral tip of the superficial MDH and adjacent paratrigeminal nucleus. WGA results show central termination sites from both the anterior ethmoidal and nasopalatine nerves within this same MDH location. Additionally, MDH Fos‐positive neurons from diving animals show extensive colocalization with WGA injected into both the anterior ethmoidal nerve and nasopalatine nerve compared to non‐diving control rats. We conclude both the anterior ethmoidal and nasopalatine nerves can provide afferent information necessary to activate MDH neurons during initiation of the mammalian diving response.Support or Funding InformationSupported by MWU Intramural funding (PFM) and CGS MBS program (MM)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Regional Anesthesia for Dentistry and Orofacial Surgery in Rhesus Macaques (Macaca mulatta).

Regional anesthesia is a commonly used adjunct to orofacial dental and surgical procedures in companion animals and humans. However, appropriate techniques for anesthetizing branches of the mandibular and maxillary nerves have not been described for rhesus monkeys. Skulls of 3 adult rhesus monkeys were examined to identify relevant foramina, establish appropriate landmarks for injection, and estimate injection angles and depth. Cadaver heads of 7 adult rhesus monkeys (4 male, 3 female) were then injected with thiazine dye to demonstrate correct placement of solution to immerse specific branches of the mandibular and maxillary nerves. Different volumes of dye were injected on each side of each head to visualize area of diffusion, and to estimate the minimum volume needed to saturate the area of interest. After injection, the heads were dissected to expose the relevant nerves and skull foramina. We describe techniques for blocking the maxillary nerve as well as its branches: the greater palatine nerve, nasopalatine nerve, and infraorbital nerve. We also describe techniques for blocking branches of the mandibular nerve: inferior alveolar nerve, mental (or incisive) nerve, lingual nerve, and long buccal nerve. Local anesthesia for the mandibular and maxillary nerves can be accomplished in rhesus macaques and is a practical and efficient way to maximize animal welfare during potentially painful orofacial procedures.

Innervation of the Nose and Nasal Region of the Rat: Implications for Initiating the Mammalian Diving Response.

Most terrestrial animals demonstrate an autonomic reflex that facilitates survival during prolonged submersion under water. This diving response is characterized by bradycardia, apnea and selective increases in peripheral vascular resistance. Stimulation of the nose and nasal passages is thought to be primarily responsible for providing the sensory afferent signals initiating this protective reflex. Consequently, the primary objective of this research was to determine the central terminal projections of nerves innervating the external nose, nasal vestibule and nasal passages of rats. We injected wheat germ agglutinin (WGA) into specific external nasal locations, into the internal nasal passages of rats both with and without intact anterior ethmoidal nerves (AENs), and directly into trigeminal nerves innervating the nose and nasal region. The central terminations of these projections within the medulla were then precisely mapped. Results indicate that the internal nasal branch of the AEN and the nasopalatine nerve, but not the infraorbital nerve (ION), provide primary innervation of the internal nasal passages. The results also suggest afferent fibers from the internal nasal passages, but not external nasal region, project to the medullary dorsal horn (MDH) in an appropriate anatomical way to cause the activation of secondary neurons within the ventral MDH that express Fos protein during diving. We conclude that innervation of the anterior nasal passages by the AEN and nasopalatine nerve is likely to provide the afferent information responsible for the activation of secondary neurons within MDH during voluntary diving in rats.