Extracranial schwannoma of the maxillary nerve misdiagnosed as trigeminal neuralgia in an elderly patient with schizophrenia - A diagnostic dilemma.

The present paper discusses the diagnostic challenges we faced in a 60-year-old woman with a history of schizophrenia, presenting with left unilateral facial pain for the past three months. Based on the elaborate clinical examination and diagnostic nerve blocks, the patient was diagnosed with trigeminal neuralgia (TN) and non-surgical therapy commenced. Further investigations with magnetic resonance imaging (MRI) and ultrasound-guided fine needle aspiration cytology (FNAC) revealed the presence of an extracranial schwannoma involving a branch of the maxillary nerve. The patient was symptomatically relieved after surgical excision of the benign tumor under general anesthesia. Hence, we emphasize the need for special care and attention in psychiatric patients presenting with orofacial pain.

A novel technique to identify the nerve of origin in head and neck schwannomas.

OBJECTIVE: Identifying the nerve of origin in head and neck schwannomas is a diagnostic challenge. Surgical management leads to a risk of permanent deficit. Accurate identification of the nerve would improve operative planning and patient counselling. METHODS: Three patients with head and neck schwannomas underwent a diagnostic procedure hypothesised to identify the nerve of origin. The masses were infiltrated with 1 per cent lidocaine solution, and the patients were observed for neurological deficits. RESULTS: All three patients experienced temporary loss of nerve function after lidocaine injection. Facial nerve palsy, voice changes with documented unilateral same-side vocal fold paralysis, and numbness in the distribution of the maxillary nerve (V2), respectively, led to a likely identification of the nerve of origin. CONCLUSION: Injection of lidocaine into a schwannoma is a safe, in-office procedure that produces a temporary nerve deficit, which may enable accurate identification of the nerve of origin of a schwannoma. Identifying the nerve of origin enhances operative planning and patient counselling.

Anatomical landmarks for maxillary nerve block in the pterygopalatine fossa: A radiological study.

INTRODUCTION: The aim of this study was to describe the anatomical landmarks for maxillary nerve block in the pterygopalatine fossa. The risk of injury to the skull base and maxillary artery was assessed. METHODS: This retrospective study was based on the analysis of 61 consecutive computed tomography angiographies obtained from patients suffering from different pathologies. Anatomical relationships between optic canal (OC), foramen rotundum (FR), inferior orbital fissure (IOF) and puncture point (PP) were assessed. A "maxillary section" was virtually carried out on the CTs, following a plane passing through PP, IOF and FR in order to mimic the anaesthesia needle route. RESULTS: No gender difference was observed except for the PP-OC distance that was longer in men. The mean PP-IOF distance was of 31.9 (± 0.7mm). PP-OC (43.9±0.5) and PP-FR (44.2±0.7) distances increased significantly with the patients height (PP-FR=17.25+0.16×height (cm); PP-OC=20.54+0.13×height (cm)). The route to the skull base was curved, with an angle of 168±1.6° at the FR level. The angle to reach the OC was greater than 7°. DISCUSSION: With a 35-mm needle length, the probability to reach the IOF was high (79%), while the risk to injure the skull base (2%) and the optical nerve (0%) was low. Artery injuries were only found in 13% of cases. Therefore, a 35-mm needle length allows for the best efficacy/risk ratio in maxillary nerve block.

[Maxillary trigeminal schwannoma. Presentation of a case and review of literature]. / Schwannoma trigeminal maxilar. Presentación de un caso y revisión de la literatura.

INTRODUCTION: Schwannomas are benign tumours that are relatively common in the head, however the involvement of the sinunasal region is rare and there are only 5 cases reported in the maxilla in current literature, representing less than 1% of bone tumours. CLINICAL CASE: We report the case of a woman with a right maxillary schwannoma who underwent a complete resection of the lesion. Emphasis is placed on the rarity of the lesion in terms of its location and includes a review of clinical behaviour, diagnosis and current treatment options. CONCLUSIONS: Maxillary trigeminal schwannoma must be suspected if vague sinunasal symptoms, paranasal mass or, as in this case, trigeminal neuralgia present. Surgical treatment is indicated, and approaches vary according to location and tumour size.

Inflammatory Pseudotumor of the Infraorbital Nerve: A Rare Diagnosis to Be Aware of.

Inflammatory pseudotumor (IPT) is a rare benign mass-forming disease that can arise anywhere throughout the body, mimicking a wide spectrum of other conditions. Its diagnosis can be challenging, especially when it involves uncommon sites. The authors report a patient of an atypical localization of IPT, occurred as an enlarging bulk in the infraorbital nerve channel in a patient who presented with facial numbness. Clinical and radiological aspects similar to schwannoma led to misdiagnosis and over-treatment. The differential diagnosis of an infraorbital mass should include IPT and the least invasive treatment should be preferred, as steroid therapy being the first-line treatment for IPT.

Implications of enlarged infraorbital nerve in idiopathic orbital inflammatory disease.

PURPOSE: To investigate the clinical characteristics of idiopathic orbital inflammatory (IOI) disease with infraorbital nerve (ION) enlargement. DESIGN: Retrospective, comparative case series. PARTICIPANTS: Consecutive patients who were diagnosed with IOI between January 2009 and December 2013 were identified. The study included patients whose medical and radiological data at diagnosis were available and whose follow-up period was more than 12 months after treatment. The patients were divided into two groups according to accompaniment of ION enlargement and were compared. MAIN OUTCOME MEASURES: clinical manifestation, radiology and treatment outcome. RESULTS: Among 89 patients with IOI, 12 (13.5%) were identified to have ION enlargement. The ION-enlarged group showed a higher percentage of the patients with diffuse inflammation (66.7%, p<0.001). 91.7% of the ION-enlarged group showed inferiorly located inflammation. Patients with ION enlargement showed a significantly higher incidence rate of proptosis (p=0.013), pain (p=0.004) and altered sensation (p<0.001). The recurrence rate was significantly higher in the ION-enlarged group (83.3%) than in the other group (33.8%) (p=0.001). Repetitive inflammation (recurrence ≥3) with steroid dependency was found only in 19.5% patients without ION enlargement but in 66.7% patients with ION enlargement. CONCLUSIONS: Patients with ION-enlarged IOI showed distinct clinical and radiological characteristics. As IOI accompanied by ION enlargement showed significantly higher steroid dependency and recurrence rate, a more careful follow-up of patients during steroid tapering might be helpful to prevent recurrence of IOI.

Trigeminal Neuralgia: Evaluation of the Relationship Between the Region of Neuralgic Manifestation and the Site of Neurovascular Compression Under Endoscopy.

This study aimed to evaluate the relationship among the pain region, branches of trigeminal nerve, and the neurovascular compression (NVC) location. A total of 123 consecutive patients with trigeminal neuralgia (TN) underwent endoscope-assisted microvascular decompression according to positive preoperative tomographic angiography. V2 alone was in 51 cases and V3 alone was in 64 cases. The location of NVC was classified into cranial, caudal, medial, or lateral sites. Some patients with multiple regions were recorded as medial + cranial, lateral + cranial, medial + caudal, and lateral + caudal. Twenty-eight (71.8%) of 39 patients with TN (V2) had their NVC at the medial site of the nerve. Twenty-seven (64.3%) of 42 patients with TN (V3) had their NVC at the lateral site of the nerve. There was a statistically significant difference (P = 0.0011 < 0.01, χ2 test). Sixteen (69.6%) of 23 patients with TN(V2) had their NVC at the cranial site of the nerve. Thirty-four (69.4%) of 49 patients with TN (V3) had their NVC at the caudal site of the nerve. There was no statistical difference (P = 0.3097 > 0.01). Evaluation of the relationship between the pain region and the NVC location by endoscopic images during microvascular decompression is more accurate. The second branch is mostly distributed in the medial area, and third branch is mainly distributed in the lateral area.

[Infraorbital schwannoma. Case report]. / Schwannoma infraorbitario. Informe de un caso.

BACKGROUND: Infraorbital schwannoma is a benign tumor of the peripheral nerve seath composed of Schwann cells. Usually occurs between 20 and 70 years of age, are usually asymptomatic and can cause progressive, painless proptosis during growth. CLINICAL CASE: A 32-year-old male admitted to ophthalmologic hospital with a painless, slowly progressive mass above the left lacrimal sac. At the ophthalmologic examination the tumor had a rubbery consistency and was firmly attached to the surrounding structures. The transillumination was negative. The B mode ultrasound disclosed a phakic eye as well as an infraorbital well-circumscribed homogeneous mass with a largest diameter of 19.7 mm, without involvement of the lacrimal pathway. The A mode ultrasound showed medium-high reflectivity with small internal vascularity. The computed tomography showed a homogeneous wellcircumscribed solid mass anterior and inferior to the left globe without bony erosion. Through subdermic incision the mass was excised. The histopathological diagnosis was "Infraorbital schwannoma". CONCLUSIONS: The schwannoma is a rare benign tumor in the orbit, few cases have been reported. The definitive diagnosis is made by histopathologic findings as the presence of a true capsule, hyper-and hypocellular areas, thickening and hyalinization of the vessel walls. When these findings are not be confused with benign fusocellular tumors. We report a new case of infraorbital schwannoma and compared it with those cases previously reported.

Antecedentes: el schwannoma infraorbitario es un tumor benigno de la vaina nerviosa periférica compuesto por células de Schwann. Suele aparecer entre los 20 y 70 años de edad, asintomático y producir proptosis progresiva e indolora durante su crecimiento. Caso clínico: paciente masculino de 32 años de edad que ingresó al hospital debido a un tumor no doloroso de crecimiento lentamente progresivo sobre el saco lagrimal izquierdo. A la exploración oftalmológica el tumor era de consistencia ahulada y estaba firmemente adherido a las estructuras vecinas. La transiluminación resultó negativa. El ultrasonido modo B mostró un ojo fáquico y un tumor infraorbitario homogéneo, bien circunstrito, con diámetro mayor de 19.7 mm, sin afectación de la vía lagrimal. El ultrasonido modo A mostró una reflectividad media-alta, con escasa vascularidad interna. La tomografía computada mostró un tumor de densidad homogénea, bien circunscrito a la región anterior y por debajo del globo ocular, sin erosión ósea. El tumor se extirpó mediante una incisión subdérmica. El diagnóstico histopatológico fue: schwannoma infraorbitario. Conclusiones: el schwannoma es un tumor benigno, poco frecuente en la órbita. Su diagnóstico definitivo se establece con base en los hallazgos histopatológicos, como: cápsula verdadera, áreas hiper e hipocelulares, engrosamiento y hialinización de las paredes vasculares. Sin esos hallazgos puede confundirse con tumores fusocelulares benignos. Se informa un nuevo caso de schwannoma infraorbitario y se compara con los casos previamente reportados.

Enlargement of the infraorbital nerve: an important sign associated with orbital reactive lymphoid hyperplasia or immunoglobulin g4-related disease.

OBJECTIVE: To describe the clinical, histopathologic, and radiologic features of a recently identified cause for enlargement of the infraorbital canal. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: Consecutive patients were identified from the orbital databases at Moorfields Eye Hospital, London, England, and the Royal Victorian Eye and Ear Hospital, Melbourne, Australia. METHODS: A retrospective, noncomparative review of the clinical case notes, radiology, and histopathology was performed. The English-language medical literature was reviewed for reports of enlargement of the infraorbital canal or nerve. MAIN OUTCOME MEASURES: Extent of clinical and radiologic changes in patients with enlargement of the infraorbital canal. RESULTS: A total of 14 patients (10 male) presented between the ages of 29 and 76 years with proptosis, eyelid swelling or a mass (10/14 cases), and periocular ache (5/14 cases). Clinical evidence of bilateral involvement was present in 6 of 14 patients. None had impairment of visual functions or facial sensation, but 4 of 14 patients had some reduction in ocular motility. Imaging showed a focal orbital mass in 10 of 14 patients (16/28 orbits), and all patients (22/28 orbits) had enlargement of some extraocular muscles. The infraorbital canal was enlarged in 20 of the 28 orbits, with associated ipsilateral orbital changes in 19 of 20 (all 14 patients) and ipsilateral maxillary sinus changes in 12 of 20 (11 patients). Biopsy-proven chronic orbital inflammation was present in all patients; this resembled reactive lymphoid hyperplasia (RLH) in 7 patients and immunoglobulin (Ig) G4-related sclerosing inflammation in 7 patients. When tested, serum IgG4 was elevated in 6 of 7 patients. Clinical or histologically proven enlargement of cervical lymph nodes was present in 7 of 14 patients. All patients responded well to systemic corticosteroid therapy, although some had a relapse upon withdrawal. One patient developed diffuse large B-cell lymphoma and subsequently leukemia, of which he later died 20 years after presentation. CONCLUSIONS: Enlargement of the infraorbital nerve and canal is rare and strongly suggests a diagnosis of RLH or IgG4-related disease, especially in the presence of ipsilateral extraocular muscle enlargement, sinus disease, or focal orbital disease.

Neonatal infraorbital nerve crush-induced CNS synaptic plasticity and functional recovery.

Infraorbital nerve (ION) transection in neonatal rats leads to disruption of whisker-specific neural patterns (barrelettes), conversion of functional synapses into silent synapses, and reactive gliosis in the brain stem trigeminal principal nucleus (PrV). Here we tested the hypothesis that neonatal peripheral nerve crush injuries permit better functional recovery of associated central nervous system (CNS) synaptic circuitry compared with nerve transection. We developed an in vitro whisker pad-trigeminal ganglion (TG)-brain stem preparation in neonatal rats and tested functional recovery in the PrV following ION crush. Intracellular recordings revealed that 68% of TG cells innervate the whisker pad. We used the proportion of whisker pad-innervating TG cells as an index of ION function. The ION function was blocked by ∼64%, immediately after mechanical crush, then it recovered beginning after 3 days postinjury and was complete by 7 days. We used this reversible nerve-injury model to study peripheral nerve injury-induced CNS synaptic plasticity. In the PrV, the incidence of silent synapses increased to ∼3.5 times of control value by 2-3 days postinjury and decreased to control levels by 5-7 days postinjury. Peripheral nerve injury-induced reaction of astrocytes and microglia in the PrV was also reversible. Neonatal ION crush disrupted barrelette formation, and functional recovery was not accompanied by de novo barrelette formation, most likely due to occurrence of recovery postcritical period (P3) for pattern formation. Our results suggest that nerve crush is more permissive for successful regeneration and reconnection (collectively referred to as "recovery" here) of the sensory inputs between the periphery and the brain stem.

Perineural invasion of cutaneous squamous cell carcinoma along the zygomaticotemporal nerve.

The vast majority of periocular squamous cell carcinoma spreads intraorbitally along the supraorbital and infraorbital nerves into the cavernous sinus. A patient presented with a history of resected squamous cell carcinoma and pain in the zygomatic distribution. She was found to have temporalis involvement of the malignancy and invasion of the zygomaticotemporal nerve by histopathology. She underwent aggressive resection and adjuvant treatment with no evidence of recurrence at 8-month follow up. This case illustrates an uncommon route of squamous cell carcinoma spread through the zygomaticotemporal sensory nerve distribution.

A study of infraorbital nerve swelling associated with immunoglobulin G4 Mikulicz's disease.

OBJECTIVES: Recent studies revealed that Mikulicz's disease (MD) should be considered as an immunoglobulin (Ig) G4-related disease with aspects of systemic disorders involving the orbit. This study aimed to analyze the relationship between Immunoglobulin G4 (IgG4)-related MD and infraorbital nerve thickness. METHODS: We measured infraorbital nerve thickness in 68 patients diagnosed as IgG4-related MD at our hospital and performed computed tomography scans of the head and neck region before treatment and compared these scans with those of the control group. RESULTS: The mean infraorbital nerve diameter (± standard deviation) was 3.2 ± 1.2 mm in patients with IgG4-related MD, and 2.6 ± 0.3 mm in the control group. Infraorbital nerves were significantly thicker in patients with IgG4-related MD. Nerve swelling was found in 20 of 68 patients (29.4%) with a cutoff value of 3.3 mm because this value was obtained from diameter of nerves in the control group + 2 standard deviation mm. No patients in the control group showed nerve swelling. In addition, we found significant correlations between infraorbital nerve swelling and serum IgG4 levels as well as the existence of multiple organ lesions. CONCLUSIONS: We found that significant infraorbital nerve swelling occurred in patients with IgG4-related MD and was thought to be a part of IgG4-related disease.

Three-dimensional courses of zygomaticofacial and zygomaticotemporal canals using micro-computed tomography in Korean.

The zygomatic nerve (ZN), which originates from the maxillary nerve at the pterygopalatine fossa, enters the orbit through the inferior orbital fissure. Within the lateral region of the orbit, the ZN divides into the zygomaticofacial (ZF) and zygomaticotemporal (ZT) nerves. The ZF and ZT nerves then pass on to the face and temporal region through the zygomaticoorbital foramen and enter their own bony canals within the zygomatic bone. However, multiple zygomaticofacial and zygomaticotemporal canals (ZFCs and ZTCs, respectively) can be observed, and their detailed intrabony courses are unknown. The aim of this study was clarify the three-dimensional intrabony courses and running patterns of the ZFCs and ZTCs, both to obtain a detailed anatomical description and for clinical purposes. Fourteen sides of the zygomatic bones were scanned as two-dimensional images using a micro-computed tomography (CT), with 32-µm slice thickness. Intrabony structures of each canals were three-dimensionally reconstructed and analyzed using Mimics computer software (Version 10.01; Materialise, Leuven, Belgium). We found that some ZTC was originated from ZFC. In 71.4% of the specimens, the ZTC(s) divided from the intrabony canal along the course of the ZFC(s). In other cases, 28.6% of ZTCs were opened through each corresponding ZT foramen. Zygomaticofacial canal originates from zygomaticoorbital foramen, divided into some of ZTCs, and is finally opened as ZF foramen. This new anatomical description of the intrabony structures of the ZFC(s) and ZTC(s) within the zygomatic bone by micro-CT technology provided helpful information to surgeons performing clinical procedures such as Le Fort osteotomy and reconstructive surgeries in the midface region.

Greater palatine foramen--key to successful hemimaxillary anaesthesia: a morphometric study and report of a rare aberration.

INTRODUCTION: Accurate localisation of the greater palatine foramen (GPF) is imperative while negotiating the greater palatine canal for blocking the maxillary nerve within the pterygopalatine fossa. The aim of this study was to define the position of the foramen relative to readily identifiable intraoral reference points in order to help clinicians judge the position of the GPF in a consistently reliable manner. METHODS: The GPF was studied in 100 dried, adult, unsexed skulls from the state of Maharashtra in western India. Measurements were made using a vernier caliper. RESULTS: The mean distances of the GPF from the midline maxillary suture, incisive fossa, posterior palatal border and pterygoid hamulus were 14.49 mm, 35.50 mm, 3.40 mm and 11.78 mm, respectively. The foramen was opposite the third maxillary molar in 73.38% of skulls, and the direction in which the foramen opened into the oral cavity was found to be most frequently anteromedial (49.49%). In one skull, the greater and lesser palatine foramina were bilaterally absent. Except for the invariably present incisive canals, there were no accessory palatal foramina, which might have permitted passage of the greater palatine neurovascular bundle in lieu of the absent GPF. To the best of our knowledge, this is the first study of such a non-syndromic presentation. CONCLUSION: The GPF is most frequently palatal to the third maxillary molar. For an edentulous patient, the foramen may be located 14-15 mm from the mid-palatal raphe or about 12 mm anterior to the palpable pterygoid hamulus.

Estudo da difusão da articaína nos tecidos orais / Articaine diffusion in oral tissues

Objetivo: Avaliar a difusão do anestésico articaína a 4% com adrenalina 1:100.000 em dentes maxilares e mandibulares, injetado através do bloqueio do nervo alveolar superior posterior (NASP). Método: Foram realizados 50 procedimentos anestésicos do bloqueio do NASP em voluntários e avaliou-se a sensibilidade da mucosa através do teste pin-prick e a sensibilidade pulpar através do teste elétrico pulp tester. As estruturas avaliadas foram: mucosa palatal posterior (túber), mucosa palatal anterior, mucosa jugal, mucosa vestibular de molares, língua, lábio inferior, primeiro pré-molar inferior (1PMI), incisivo lateral inferior (ILI), primeiro molar inferior (1MI), primeiro pré-molar superior (1PMS), incisivo lateral superior (ILS), primeiro molar superior (1MS). Resultados: Foi observado que, ao analisar a insensibilidade mucosa, a efetividade da articaína em insensibilizar as estruturas testadas quando administrada através do bloqueio do NASP foi crescente com o decorrer do tempo e que os 1MS e 1PMS tiveram um tempo de latência inferior às demais unidades dentárias testadas. Observou-se que a insensibilidade pulpar foi crescente com o decorrer do tempo e que os 1MS e 1PMS tiveram um tempo de latência inferior às demais unidades dentárias testadas. O ILS e as unidades dentárias inferiores 1MI e 1PMI necessitaram de um tempo de latência de 4 minutos para começarem a apresentar insensibilidade pulpar. Os ILI apresentaram o maior índice de insucesso de anestesia pulpar (74%) e o insucesso da anestesia do 1MS foi de 6%, a menor entre os dentes testados. Conclusões: Os resultados sugerem haver uma difusão da articaína no sentido ântero-posterior na maxila e a difusão vestíbulo-palatal da droga. A articaína quando administrada através do bloqueio do NASP suprime a necessidade da anestesia do palato.

Objective: The purpose of this research was to evaluate the diffusion of 4% articaine with 1:100,000 adrenaline injected through posterior superior alveolar (PSA) nerve block in maxillary and mandibular teeth. Method: Fifty PSA nerve block procedures were performed in volunteers. The sensitivity of the mucosa was evaluated by the pin-prick test and pulp sensitivity was assessed by electric pulp testing. The following structures were evaluated: posterior palatal mucosa (tuber), anterior palatal mucosa, cheek mucosa, molar buccal mucosa, tongue, lower lip, mandibular first premolar (MD1PM), mandibular lateral incisor (MDLI), mandibular first molar (MD1M), maxillary first premolar (MX1PM), maxillary lateral incisors (MXLI) and maxillary first molar (MX1M). Results: The analysis of mucosa numbness and pulp numbness revealed that the efficacy of PSA nerve block with articaine to desensitize the tested structures increased with time and that the MX1M and MX1PM had shorter latency periods than the other tooth groups. The MXLI and MD1M and MD1PM required 4 minutes to start pulp numbness. MDLI showed the highest failure rate of pulpal anesthesia (74%) and MX1M had the lowest failure rate among all test (around 6%). Conclusion: The results suggest an anterior-posterior diffusion of articaine in the maxilla and a bucco-palatal diffusion of the drug. PSA nerve block with articaine eliminates the need for anesthesia of the palate.

The usefulness of infraorbital nerve enlargement on MRI imaging in clinical diagnosis of IgG4-related orbital disease.

PURPOSE: To investigate the frequency of infraorbital nerve enlargement (IONE) in orbital lymphoproliferative disorders, and to show that IONE can contribute to the clinical diagnosis of IgG4-related orbital diseases (IgG4-ROD). SUBJECTS AND METHODS: 71 cases in which orbital lymphoproliferative disorders were diagnosed at Okayama Medical Center and Mitoyo General Hospital from April, 2004 to March, 2011 were investigated. The male-to-female ratio was 39:32, and the age range 27-87 years old (average age 64.1 years). Whenever the coronal section of the infraorbital nerve was larger than that of the optic nerve on MRI, it was defined as IONE. RESULTS: The breakdown of the 71 cases was: 45 cases of non-Hodgkin lymphoma, 16 cases of IgG4-ROD, 5 cases of reactive lymphoid hyperplasia, and 5 cases of idiopathic orbital inflammation. Of these, a total of 9 cases had IONE. The incidence of IONE was compared between the IgG4-ROD patient group and the non-IgG4-ROD patient group and was significantly higher in the IgG4-ROD patient group (p < 0.0001). CONCLUSION: If IONE is observed in a case of orbital lymphoproliferative disorders on MRI, then it is highly possible that such a case is IgG4-ROD.

Avaliação do desconforto palatal após diferentes técnicas de infiltração vestibular de articaína na maxila / Evaluation of palatal discomfort after different techniques of buccal infiltration of articaine in the maxilla

Objetivo: Comparar o efeito anestésico da infiltração vestibular maxilar (IVM) e do bloqueio do nervo alveolar superior posterior (BNASP) usando articaína 4% com adrenalina 1:100.000 no desconforto na mucosa palatal averiguado pelo teste pin-prick. Método: Neste estudo randomizado, duplo-cego e cruzado foram selecionados 30 voluntários saudáveis os quais foram submetidos a duas diferentes técnicas anestésicas no vestíbulo da maxila (IVM e BNASP) usando articaína 4% com adrenalina 1:100.000. As injeções foram administradas pelo mesmo operador em duas sessões distintas com intervalo de uma semana entre elas. A anestesia dos tecidos moles do palato foi avaliada pelo teste pin-pick com uma agulha 30G por um operador cego para o tipo de injeção. O desconforto da picada de agulha foi avaliado em quatro momentos utilizando uma escala visual analógica (EVA) de 100 mm. Os dados da EVA foram categorizados como: nenhuma dor a dor leve (0-30 mm) e dor moderada a grave (maior que 30 mm). Os dados foram analisados pelo teste Qui-quadrado e os resultados foram estatisticamente significativos quando p menor que 0,05. Resultados: Apesar de ambas as técnicas puderem insensibilizar o palato, a técnica IVM é menos funcional que a técnica BNASP na insensibilização palatal, não atingindo os mesmos objetivos num mesmo intervalo de tempo. O bloqueio do nervo alveolar superior posterior se mostrou mais efetivo na insensibilização do palato aos 5 minutos (p menor que 0,001) enquanto não houve diferença estatisticamente significante aos 10 minutos (p = 0,87). Conclusões: O BNASP com articaína 4% e adrenalina 1:100.000 foi mais eficaz que o IVM na redução do desconforto pin-prick do tecido mole do palato, aos cinco minutos pós-injeção. Ambas as técnicas foram igualmente eficazes em dez minutos.

Objective: To compare the effect of maxillary buccal infiltration (BI) and posterior superior alveolar nerve block (PSANB) using 4% articaine with 1:100,000 epinephrine on pin-prick discomfort on palatal mucosa. Methods: Thirty healthy subjects participated in this double-blind cross-over study. Each subject received two different maxillary buccal anesthetic techniques with 4% articaine with 1:100.000 epinephrine, namely BI and PSANB. Injections were given by the same operator in different sessions with 1-week interval between them. Anesthesia of palatal soft tissue was assessed by the pin-pick test with a 30G needle by an operator blinded to the type of injection. Discomfort of pin-prick was assessed at four time points using a 100 mm visual analogue scale (VAS). Data from the VAS were categorized as none to mild pain (0-30 mm) and moderate to severe pain (greater than 30 mm). Data were analyzed by Chi-square test and the results were statistically significant when p less than 0.05. Results: Although both techniques could numb the palate, the BI technique appeared less functional that the PSANB technique, not reaching the same goals in the same time interval. PSANB was more effective in stunning the palate at 5 minutes (p less than 0.001) while there was no statistically significant difference between the techniques at 10 minutes (p = 0.87). Conclusions: PSANB with 4% articaine and 1:100,000 epinephrine was more effective than BI in reducing pin-prick discomfort of palatal soft tissue at 5 minutes post-injection. Both techniques were equally effective at 10 minutes.