Application of oxytocin with low-level laser irradiation suppresses the facilitation of cortical excitability by partial ligation of the infraorbital nerve in rats: An optical imaging study.

The effects of current treatments for neuropathic pain are limited. Oxytocin is a novel candidate substance to relieve neuropathic pain, as demonstrated in various animal models with nerve injury. Low-level laser therapy (LLLT) is another option for the treatment of neuropathic pain. In this study, we quantified the effects of oxytocin or LLLT alone and the combination of oxytocin and LLLT on cortical excitation induced by electrical stimulation of the dental pulp using optical imaging with a voltage-sensitive dye in the neuropathic pain model with partial ligation of the infraorbital nerve (pl-ION). We applied oxytocin (OXT, 0.5 µmol) to the rat once on the day of pl-ION locally to the injured nerve. LLLT using a diode laser (810 nm, 0.1 W, 500 s, continuous mode) was performed daily via the skin to the injured nerve from the day of pl-ION to 2 days after pl-ION. Cortical responses to electrical stimulation of the mandibular molar pulp under urethane anesthesia were recorded 3 days after pl-ION. Both the amplitude and area of excitation in the primary and secondary somatosensory and insular cortices in pl-ION rats were larger than those in sham rats. The larger amplitude of cortical excitation caused by pl-ION was suppressed by OXT or LLLT. The expanded area of cortical excitation caused by pl-ION was suppressed by OXT with LLLT but not by OXT or LLLT alone. These results suggest that the combined application of OXT and LLLT is effective in relieving the neuropathic pain induced by trigeminal nerve injury.

Nerve electrical stimulation enhances osseointegration of implants in the beagle.

Dental implantation has been the primary method for the treatment of tooth loss, but longer than 3 months healing times are generally required. Because immediate load implants are suitable only for certain categories of implant patients, it has value to develop a novel method to facilitate the implant-bone osseointegration process. Cylindrical titanium implants were implanted in the tooth sockets of beagles, and microelectrode stimulation of the sympathetic nerves in the infraorbital nerve was performed after implantation for 1 week. The authors found that one-sided nerve stimulation was shown to evoke consistent electric potential changes in both sides of the infraorbital nerves. Moreover, after 4 weeks of implantation, more new bone was clearly observed around the implants in the beagles that received electrical stimulation treatment than was observed in the control animals. Furthermore, a higher mineralization density was measured in the new peri-implant bone tissues of the stimulated beagles when compared to controls. These results demonstrate that the simple and safe physical method of microelectrode stimulation to sympathetic nerves can promote the formation of new bone and the osseointegration of implants. This technique is worth promoting and has the potential to reduce the healing time of dental implantation in future clinical cases.

Bilateral suprazygomatic maxillary nerve blocks vs. infraorbital and palatine nerve blocks in cleft lip and palate repair: A double-blind, randomised study.

BACKGROUND: Cleft defects are common craniofacial malformations which require early surgical repair. These patients are at high risk of postoperative airway obstruction and respiratory failure. Cleft surgery may require high doses of opioids which may contribute to these complications. OBJECTIVES: To compare the effectiveness of proximal and distal approaches to blocking the maxillary nerve in patients undergoing cleft lip or cleft palate surgery. DESIGN: Randomised, controlled and double-blind study. SETTING: The current study was carried out in Guwahati (Assam, India) between April 2014 and June 2014. PATIENTS: A total of 114 patients older than 6 months who underwent cleft lip or cleft palate surgery were included. Exclusion criteria included coagulation disorders, peripheral neuropathy or chronic pain syndrome, infection in the puncture site, allergy to local anaesthetics, lack of consent and language problems or other barriers that could impede the assessment of postoperative pain. INTERVENTIONS: Patients were randomly assigned to one of two groups: proximal group (bilateral suprazygomatic maxillary nerve blocks) and distal group (bilateral infraorbital nerve blocks for cleft lip repair and bilateral greater and lesser palatine nerve blocks and nasopalatine nerve block for cleft palate surgery). MAIN OUTCOME MEASURE: The primary endpoint was the percentage of patients requiring extra doses of opioids. Secondary endpoints included pain scores, respiratory and nerve block-related complications during the first 24 h. RESULTS: In the intra-operative period, there was a significant reduction of nalbuphine consumption in the proximal group (9.1 vs. 25.4%, P = 0.02). The percentage of patients requiring intra-operative fentanyl was lower in the proximal group (16.4 vs. 30.5%, P = 0.07). There were no differences in either postoperative pain scores or in postoperative complications. No technical failure or block-related complications were reported. CONCLUSION: Bilateral suprazygomatic maxillary nerve block is an effective and safe alternative to the traditional peripheral nerve blocks for cleft lip and cleft palate surgery, in a mixed paediatric and adult population.

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.

A Cadaveric Study of Ultrasound-Guided Maxillary Nerve Block Via the Pterygopalatine Fossa: A Novel Technique Using the Lateral Pterygoid Plate Approach.

BACKGROUND AND OBJECTIVES: This study aimed to describe and assess the accuracy and feasibility of a novel technique for ultrasound-guided maxillary nerve block using the lateral pterygoid plate (LPP) approach via the pterygopalatine fossa (PPF) in a soft cadaveric model. METHODS: Ten soft cadavers were studied. The curved array ultrasound transducer probe was applied over 1 side of the face of the cadavers in the open-mouth posture. It was placed transversely below the zygomatic arch for identifying the border of the maxillary tuberosity and the LPP. We tilted the curve probe from the caudal to the cranial direction until the uppermost part of the PPF was identified. The in-plane needle approach was used from the anterior-to-posterior and lateral-to-medial directions through the fossa, and 3 mL of methylene blue dye was injected. RESULTS: The spread of injectate after ultrasound-guided maxillary nerve block using the LPP approach was successfully performed in all cadavers as demonstrated by visualized moderate to marked traces of methylene blue within the PPF. No accidental injections in the maxillary arteries or facial nerves were observed. CONCLUSIONS: This cadaveric study suggests that ultrasound-guided maxillary nerve block using the LPP approach via the PPF has a high degree of accuracy and feasibility. Further studies are required to confirm its efficacy and safety for clinical application.

Impact of age on the anatomy of the pediatric pterygopalatine fossa and its relationship to the suprazygomatic maxillary nerve block.

OBJECTIVES: The suprazygomatic maxillary nerve block is associated with improved post-operative pain management after select craniofacial surgical procedures. This study's objective is to better define the impact of pediatric facial skeletal growth on techniques for accessing the pterygopalatine fossa (PPF). METHODS: Pediatric patients with prior thin-slice maxillofacial computed tomography imaging were identified in an institutional radiology database. Aquarius image-processing software (Ver. 4.4.11, TeraRecon, Inc., Foster City, CA) was used to measure from the suprazygomatic skin to the greater wing of the sphenoid where the needle is then re-oriented in an anterior and inferior trajectory allowing it to advance into the PPF. RESULTS: A total of 90 patients ranging from 0 to ≤18 years of age were included in the study. The mean distance from the suprazygomatic skin to the foramen rotundum in patients 0 to ≤12 months of age and >13 to ≤18 years of age was 38.6 (SD ±â€¯4.7) and 47.1 (SD ±â€¯3.2) mm, respectively (p < .0001). The statistical analysis demonstrated a positive correlation between age in years and all of the measured distances (p = .0001). With respect to the plane of the needle entry site, the anterior and inferior angles required for passage into the PPF in the 0 to ≤12 months age group were 11 (SD ±â€¯2.1) and 9.0 (SD ±â€¯2.5) degrees, respectively, compared to those in the >13 to ≤18 years of age group at 12.4 (SD ±â€¯1.9) and 12.1 (SD ±â€¯3.2) degrees, respectively. These data reveal that patients in the oldest compared to the youngest pediatric age groups require significantly greater needle insertion, yet the angles of needle re-orientation are clinically similar between these two pediatric age groups varying by up to only 3°. CONCLUSION: As expected, the distance from the skin to the foramen rotundum increases significantly with age; however, the angles of re-orientation with respect to the original needle entry site demonstrated up to only 3° of variability between the youngest and oldest age groups evaluated in this pediatric cohort.

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.

Evaluation of 2-Stage Injection Technique in Children.

Effective pain control during local anesthetic injection is the cornerstone of behavior guidance in pediatric dentistry. The aim of this study was to evaluate the practical efficacy of a 2-stage injection technique in reducing injection pain in children. This was a split-mouth, randomized controlled crossover trial. One hundred cooperative children aged 7 to 13 years in need of bilateral local anesthetic injections (inferior alveolar nerve block, posterior superior alveolar nerve block, or maxillary and mandibular buccal infiltrations) for restorative, endodontic, and extraction treatments were recruited for the study. Children were randomly allocated to receive either the 2-stage injection technique or conventional technique at the first appointment. The other technique was used at the successive visit after 1 week. Subjective and objective evaluation of pain was done using the Wong-Baker FACES Pain Rating Scale (FPS) and Sound Eye Motor (SEM) scale, respectively. The comparison of pain scores was done by Wilcoxon sign-rank test. Both FPS and SEM scores were significantly lower when the 2-stage injection technique of local anesthetic nerve block/infiltration was used compared with the conventional technique. The 2-stage injection technique is a simple and effective means of reducing injection pain in children.

The Anesthetic Effect of Anterior Middle Superior Alveolar Technique (AMSA).

Anesthesia of the soft and hard tissues of the maxilla may require up to 5 injections. Thus, the aim of this study was to evaluate the anesthetic efficacy of the anterior middle superior alveolar (AMSA) and supraperiosteal injection techniques during subgingival scaling and root planing (SRP). Thirty individuals with periodontitis were scheduled for SRP on the buccal aspect of teeth in the anterior maxilla. Before SRP, on a randomly chosen side of the maxilla, the supraperiosteal injection was performed in 1 session, while the AMSA injection was conducted in the contralateral side of the same patient in another session. Immediately after each SRP session, patients rated their pain perception during the procedure with a visual analog scale. No statistically significant differences in mean pain ratings during SRP were found after both anesthetic techniques (P > .05). This preliminary study demonstrated that the AMSA and supraperiosteal injection techniques provided similar anesthetic comfort during SRP. The AMSA injection could be an alternative to anesthetize the buccal aspect of maxilla, without the undesirable effects on facial structures such as the upper lip, nostrils, and lower eyelids. However, further randomized clinical trials with larger samples are necessary to confirm such results.

Efficacy of Benzocaine 20% Topical Anesthetic Compared to Placebo Prior to Administration of Local Anesthesia in the Oral Cavity: A Randomized Controlled Trial.

The aim of the present study was to compare the effects of a topical anesthetic to a placebo on pain perception during administration of local anesthesia in 2 regions of the oral cavity. A split-mouth, double-blind, randomized clinical trial design was used. Thirty-eight subjects, ages 18-50 years, American Society of Anesthesiologists I and II, received 4 anesthetic injections each in regions corresponding to the posterior superior alveolar nerve (PSA) and greater palatine nerve (GPN), totaling 152 sites analyzed. The side of the mouth where the topical anesthetic (benzocaine 20%) or the placebo was to be applied was chosen by a flip of a coin. The needle used was 27G, and the anesthetic used for administration of local anesthesia was 2% lidocaine with 1:100,000 epinephrine. After receiving the administration of local anesthesia, each patient reported pain perception on a visual analog scale (VAS) of 100-mm length. The results showed that the topical anesthetic and the placebo had similar effects: there was no statistically significant VAS difference between the PSA and the GPN pain ratings. A higher value on the VAS for the anesthesia of the GPN, relative to the PSA, was observed for both groups. Regarding gender, male patients had higher values on the VAS compared with female patients, but these differences were not meaningful. The topical anesthetic and the placebo had similar effects on pain perception for injection of local anesthesia for the PSA and GPN.

Painful stimulation and transient blocking of nerve transduction due to local anesthesia evoke perceptual distortions of the face in healthy volunteers.

UNLABELLED: Anecdotally, orofacial pain patients sometimes report that the painful face area feels "swollen." Because there are no clinical signs of swelling, such illusions may represent perceptual distortions. In this study, we examine whether nociceptive stimulation can lead to perceptual distortion of the face in a way similar to that of local anesthesia. Sixteen healthy participants received injections of .4 mL hypertonic saline to induce short-term nociceptive stimulation, .4 mL mepivacaine (local anesthetic) to transiently block nerve transduction, and .4 mL isotonic saline as a control condition. Injections were administered in both the infraorbital and the mental nerve regions. Perceptual distortions were conceptualized as perceived changes in magnitude of the injected areas and the lips, and they were measured using 1) a verbal subjective rating scale and 2) a warping procedure. Prior to the study, participants filled in several psychological questionnaires. This study shows that both nociceptive stimulation (P < .05) and transient blocking of nerve transduction (P < .05) can lead to perceptual distortion of the face. A test-retest experiment including 9 new healthy subjects supported the results. Perceptual distortions were positively correlated with the psychological variable of dissociation in several conditions (P < .05). Perceptual distortions may therefore be influenced by somatosensory changes and psychological mechanisms. PERSPECTIVE: Knowledge of the factors that influence the perception of the face is important to understand the possible implications of perceptual distortions in orofacial pain disorders (and possibly other chronic pain states). Such information may ultimately open up new avenues of treatment for persistent orofacial pain.

Involvement of astroglial glutamate-glutamine shuttle in modulation of the jaw-opening reflex following infraorbital nerve injury.

To evaluate the mechanisms underlying orofacial motor dysfunction associated with trigeminal nerve injury, we studied the astroglial cell activation following chronic constriction injury (CCI) of the infraorbital nerve (ION) immunohistochemically, nocifensive behavior in ION-CCI rats, and the effect of the glutamine synthase (GS) blocker methionine sulfoximine (MSO) on the jaw-opening reflex (JOR), and also studied whether glutamate-glutamine shuttle mechanism is involved in orofacial motor dysfunction. GFAP-immunoreactive (IR) cells were observed in the trigeminal motor nucleus (motV) 3 and 14 days after ION-CCI, and the nocifensive behavior and JOR amplitude were also strongly enhanced at these times. The number of GS- and GFAP-IR cells was also significantly higher in ION-CCI rats on day 7. The amplitude and duration of the JOR were strongly suppressed after MSO microinjection (m.i.) into the motV compared with that before MSO administration in ION-CCI rats. After MSO administration, the JOR amplitude was strongly suppressed, and the duration of the JOR was shortened. Forty minutes after m.i. of glutamine, the JOR amplitude was gradually returned to the control level and the strongest attenuation of the suppressive effect of MSO was observed at 180 min after glutamine m.i. In addition, glutamine also attenuated the MSO effect on the JOR duration, and the JOR duration was extended and returned to the control level thereafter. The present findings suggest that astroglial glutamate-glutamine shuttle in the motV is involved in the modulation of excitability of the trigeminal motoneurons affecting the enhancement of various jaw reflexes associated with trigeminal nerve injury.

Bilateral suprazygomatic maxillary nerve block for cleft palate repair in children: a prospective, randomized, double-blind study versus placebo.

BACKGROUND: The authors investigated the efficacy of bilateral suprazygomatic maxillary nerve block (SMB) for postoperative pain relief in infants undergoing cleft palate repair. METHODS: In this prospective, double-blind, single-site, randomized, and parallel-arm controlled trial, 60 children were assigned to undergo bilateral SMB with general anesthesia with either 0.15 ml/kg of 0.2% ropivacaine (Ropi group) or 0.15 ml/kg of isotonic saline (Saline group) on each side. The primary endpoint was total postoperative morphine consumption at 48 h. Pain scores and respiratory- and SMB-related complications were noted. RESULTS: The overall dose of intravenous morphine after 48 h (mean [95% CI]) was lower in the Ropi group compared with that in the Saline group (104.3 [68.9 to 139.6] vs. 205.2 [130.7 to 279.7] µg/kg; P = 0.033). Continuous morphine infusion was less frequent in the Ropi group compared with that in the Saline group (1 patient [3.6%] vs. 9 patients [31%]; P = 0.006). Three patients in the Saline group had an episode of oxygen desaturation requiring oxygen therapy. There were no technical failures or immediate complications of the SMB. Intraoperative hemodynamic parameters, doses of sufentanil, pain scores, and postoperative hydroxyzine requirements were not different between the two groups. CONCLUSION: Bilateral SMB is an easy regional anesthesia technique that reduces total morphine consumption at 48 h after cleft palate repair in children and the use of continuous infusion of morphine and may decrease postoperative respiratory complications.

Prolonged peripheral nerve blockade in patients using lithium carbonate.

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

Effects of tapentadol on mechanical hypersensitivity in rats with ligatures of the infraorbital nerve versus the sciatic nerve.

BACKGROUND: Convergent data showed that neuropathic pain has specific characteristics at cephalic versus extra-cephalic level, where single-targeted drugs differentially alleviate pain. Because the novel analgesic drug, tapentadol, is acting at two targets, µ-opioid receptors (as agonist) and noradrenaline reuptake (as inhibitor), we tested its effects on neuropathic pain at both cephalic and extra-cephalic levels. METHODS: Sprague-Dawley rats underwent unilateral constriction injury (CCI) to the infraorbital nerve (ION; cephalic territory) or the sciatic nerve (SN; extra-cephalic territory), and alleviation of nerve lesion-induced mechanical allodynia/hyperalgesia was assessed after acute or repeated (for 4 days) treatment with tapentadol compared with morphine and/or reboxetine (noradrenaline reuptake inhibitor) 2 weeks after surgery. Possible changes in the expression of the neuroinflammatory markers activating transcription factor 3 (ATF3), interleukin-6 (IL-6) and brain-derived neurotrophic factor (BDNF) by repeated tapentadol treatment were quantified by real-time reverse transcription polymerase chain reaction in ganglia and central tissues. RESULTS: Acute administration of tapentadol (1-10 mg/kg, i.p.) significantly reduced allodynia in both CCI-SN and CCI-ION rats. Although morphine (3 mg/kg, s.c.) or reboxetine (10 mg/kg, i.p.) alone was only marginally active, the combination of both drugs produced supra-additive effects like those observed with tapentadol. In contrast to repeated morphine whose effects vanished, the anti-allodynic effects of tapentadol remained unchanged after a 4-day treatment. However, the latter treatment with tapentadol did not affect nerve lesion-evoked overexpression of ATF3, IL-6 and BDNF transcripts. CONCLUSIONS: The dual synergistic pharmacological properties of tapentadol, which result in clear-cut anti-neuropathic pain effects at both cephalic and extra-cephalic levels, probably involve mechanisms downstream of nerve injury-induced neuroinflammatory reaction.

Local anesthesia: agents, techniques, and complications.

This article outlines the different classes of local anesthetics available for dental procedures. It also gives an overview of the mechanism of action and metabolism of each different class of local anesthetic. Furthermore, it discusses indications and contraindications of each local anesthetic and the proper dosage of each. The techniques for the administration of local anesthetics with the relevant anatomy are explained. An overview is given of the possible complications that can occur because of local anesthetic use and their possible treatment options.

Is clonidine an adequate alternative to epinephrine as a vasoconstrictor in patients with hypertension?

PURPOSE: To evaluate the safety and efficacy of an admixture of lidocaine with clonidine with regard to the anesthetic abilities, hemodynamic parameters, and postoperative pain control and to compare the results with those obtained with a lidocaine-epinephrine solution. MATERIALS AND METHODS: A total of 50 patients with poorly controlled, moderate hypertension (American Society of Anesthesiologists class II) who presented for uncomplicated upper third molar extraction were included in a double-blind study. The time of onset of action, duration, and intensity of anesthesia and the vasoconstrictor properties were evaluated. The hemodynamic changes (ie, systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, ST-segment depression of 1 mm or greater, and cardiac arrhythmias) were recorded. The presence of postoperative pain and analgesic requirements were also compared. The results were analyzed using an unpaired, type sample equal-variance t test with the Bonferroni correction. RESULTS: Of the 50 patients with hypertension (American Society of Anesthesiologists class II), 25 received 2 mL of 2% lidocaine with clonidine (15 µg/mL) and 25 received lidocaine with epinephrine (12.5 µg/mL). There were no significant differences between the 2 agents with regard to the time of onset of action, duration or intensity of anesthesia, or the vasoconstrictor properties. The clonidine group showed better hemodynamic parameters compared with the epinephrine group. The clonidine group showed significantly lesser postoperative pain and, therefore, had lesser analgesic consumption. CONCLUSIONS: Clonidine could be a useful and safe alternative to epinephrine for intraoral block anesthesia with lidocaine in patients with hypertension and American Society of Anesthesiologists class II.

Transient diplopia with ipsilateral abducent nerve palsy and ptosis following a maxillary local anesthetic injection: a case report and review of literature.

BACKGROUND: The posterior superior alveolar (PSA) nerve block is commonly used in dentistry for treatment of the maxillary molars. Although this procedure is associated with many complications, ocular complications have been rarely reported. CASE REPORT: This report details an iatrogenic paresis of the abducent nerve and partial palsy of the oculomotor nerve leading to diplopia, strabismus and ptosis following a PSA nerve block and extraction of maxillary right second molar. The patient was treated symptomatically, and the recovery was uneventful. Relevant anatomical pathways with review of literature are discussed. DISCUSSION: Although rare, the dentist should be aware of these complications to avoid being perplexed by this unexpected circumstance, thus adversely affecting the doctor-patient trust.

PSA block for maxillary molar's anesthesia - an obsolete technique?

BACKGROUND: Routine use of posterior superior alveolar (PSA) nerve block or maxillary infiltration for the removal of maxillary molars has been validated. OBJECTIVE: The present study was undertaken to determine the relative contribution of posterior superior alveolar (PSA) block in cases of anesthesia required for maxillary molars. STUDY DESIGN: One hundred patients requiring removal of maxillary second and third molars were enrolled. These patients were divided into 2 groups. One group received infiltration for anesthesia and other group received PSA nerve block using lignocaine with vasoconstrictor. All extractions were performed using a consistent technique of intraalveolar extraction. Data relating to the pain during extraction obtained on a visual analog scale and a verbal response scale, requirement of repeated injection for anesthesia, efficacy of these injections in localized infections, and requirement of rescue analgesics 3 hours after extraction. RESULTS: Statistical data confirmed clinical equivalence between infiltration and PSA nerve block. CONCLUSIONS: Considering the difficulty in mastering the technique of PSA nerve block, and the possibility of more complications associated with it (compared with infiltration); it may not be necessary for anesthesia of maxillary molars.