Occurrence of paresthesia after dental local anesthetic administration in the United States

Effective anaesthesia of the acutely inflamed pulp: part 2. Clinical strategies

Achieving profound pulpal anaesthesia in a mandibular molar diagnosed with irreversible pulpitis can be argued to be the most testing of dental anaesthetic challenges. Following discussion on the possible reasons for this occurrence in part 1, part 2 outlines the various local anaesthetic techniques that practitioners can use to overcome the acutely inflamed mandibular molar. They should then be able to apply these same principles to help anaesthetise any other tooth presenting with an acutely inflamed pulp. Techniques are discussed in detail along with key variables that have been associated with having an impact on the anaesthetic efficacy. This is to bring to light factors that can aid anaesthetic success as well as dispel common misnomers.

Evaluation of Buccal Infiltration with Articaine and Inferior Alveolar Nerve Block with Lignocaine for Pulp Therapy in Mandibular Primary Molars

OBJECTIVE

Failure of inferior alveolar nerve block in achieving profound anesthesia of the pulp due to various reasons has led to the introduction of more potent local anesthetic agents like articaine. This study was conducted to compare the efficacy of buccal infiltration with articaine in achieving pulpal anesthesia of primary molars as compared to inferior alveolar nerve block with lignocaine.

STUDY DESIGN

30 patients (4-8 years) with indication of pulp therapy in at least two mandibular primary molars were selected. Patients were randomly assigned to receive nerve block with lignocaine or infiltration with articaine on first appointment and the other solution on second appointment. All the pulpotomies and pulpectomies were performed by a pediatric dentist. Two researchers standing at a distance of 1.5 m recorded the Pain Scores and Sound, Eye, Motor (SEM) scores. After the completion of procedure, the patient was asked to record the Facial Image score and Heft-Parker Visual Analogue Score (HP-VAS).

RESULTS

Pain Score recorded at the time of injection showed significantly more movements with block as compared to infiltration (p<0.001). SEM scores at time of pulp extirpation were also higher for block than infiltration (p<0.001).

CONCLUSION

Articaine infiltration has the potential to replace inferior alveolar nerve block for primary mandibular molars.

Comparison of the Efficacy of Local Infiltration and Mandibular Block Anesthesia With Articaine for Harvesting Ramus Grafts

PURPOSE

We compared the efficacy of local infiltrative anesthesia and regional mandibular block anesthesia using articaine to harvest ramus grafts and the postoperative sequelae.

MATERIALS AND METHODS

A total of 20 patients with alveolar bone deficiency participated in the present comparative, prospective, randomized study. The first group received regional anesthesia with the mandibular block technique (group A; n = 10), and those in the second group received local infiltration anesthesia (group B; n = 10). Intraoperative pain and bleeding were evaluated as the primary outcome variables. The visual analog scale (VAS) scores were compared at 0.5, 1, 2, and 4 hours postoperatively. The maximal interincisal mouth opening (MIO) (on days 3 and 7) and VAS scores (at 6, 12, 24, and 48 hours and on days 3 and 7) were compared as secondary outcome variables. The correlation between pain (VAS scores) and trismus (MIO) were also compared.

RESULTS

A painless procedure was performed in both groups. The VAS score, MIO, and intraoperative bleeding were not significantly different between the 2 groups. Paresthesia was not observed in either group postoperatively. No statistically significant correlations were found between the VAS scores and MIO.

CONCLUSIONS

Local infiltrative anesthesia preserves almost the same depth of anesthesia as mandibular block anesthesia. No differences were found between these techniques in terms of efficacy and postoperative sequelae during and after ramus graft harvest. Thus, using articaine with a local infiltration technique is an alternative to mandibular block anesthesia during ramus graft harvesting and results in a reduced risk of inferior alveolar nerve damage.

Anesthetic Efficacy in Irreversible Pulpitis: A Randomized Clinical Trial

Abstract Inferior alveolar nerve block has a high failure rate in the treatment of mandibular posterior teeth with irreversible pulpitis. The aim of this study was to compare the anesthetic efficacy of 4% articaine, 2% lidocaine and 2% mepivacaine, all in combination with 1:100,000 epinephrine, in patients with irreversible pulpitis of permanent mandibular molars during a pulpectomy procedure. Sixty-six volunteers from the Emergency Center of the School of Dentistry, University of São Paulo, randomly received 3.6 mL of local anesthetic as a conventional inferior alveolar nerve block (IANB). The subjective signal of lip numbness, pulpal anesthesia and absence of pain during the pulpectomy procedure were evaluated respectively, by questioning the patient, stimulation using an electric pulp tester and a verbal analogue scale. All patients reported the subjective signal of lip numbness. Regarding pulpal anesthesia success as measured with the pulp tester, the success rate was respectively 68.2% for mepivacaine, 63.6% for articaine and 63.6% for lidocaine. Regarding patients who reported no pain or mild pain during the pulpectomy, the success rate was, respectively 72.7% for mepivacaine, 63.6% for articaine and 54.5% for lidocaine. These differences were not statistically significant. Neither of the solutions resulted in 100% anesthetic success in patients with irreversible pulpitis of mandibular molars.

Comparison of anesthetic efficacy of 2 and 4 % articaine in inferior alveolar nerve block for tooth extraction-a double-blinded randomized clinical trial

OBJECTIVES

The purpose of this clinical prospective, randomized, double-blind trial was to compare the anesthetic efficacy of 2 % articaine and 4 % articaine in inferior alveolar nerve block anesthesia for extraction of mandibular teeth.

MATERIALS AND METHODS

In 95 patients, 105 lower molar and premolar teeth were extracted after intraoral inferior alveolar nerve block. In 53 cases, 2 % articaine (group I) and, in 52 cases, 4 % articaine (group II) was administered. The primary objective was to analyze the differences of anesthetic effects between the two groups (complete/sufficient vs. insufficient/none). Furthermore, differences in pulpal anesthesia (onset and depth, examined with pulp vitality tester (min)), as well as in length of soft tissue anesthesia (min), were evaluated. Additionally, the need of a second injection, pain while injecting (numeric rating scale (NRS)), pain during treatment (NRS), pain after treatment (NRS), and other possible complications (excessive pain, bleeding events, prolonged deafness) were analyzed.

RESULTS

Anesthesia was sufficient for dental extractions in both groups without significant differences (p = 0.201). The onset of anesthesia did not differ significantly (p = 0.297). A significantly shorter duration of soft tissue anesthesia was seen in group I (2.9 vs. 4 h; p < 0.001). There was no significant difference in the need for a second injection (p = 0.359), in injection pain (p = 0.386), as well as in pain during (p = 0.287) or after treatment (p = 0.121). In both groups, no complications were seen.

CONCLUSIONS

The local anesthetic effect of the 4 % articaine solution is not significantly better when compared to 2 % articaine.

CLINICAL RELEVANCE

For mandibular tooth extraction, articaine 2 % may be used as alternative as well.

Anaesthetic efficacy of unilamellar and multilamellar liposomal formulations of articaine in inflamed and uninflamed tissue

We compared the efficacy of articaine encapsulated in multilamellar and unilamellar liposomes with that of articaine with epinephrine, after infiltration into inflamed and uninflamed tissue in rats. We encapsulated 4% articaine in multilamellar (articaine:multi) and unilamellar (articaine:uni) liposomes and compared them with 4% articaine with 1:100 000 epinephrine (articaine:epinephrine), in inflamed (plantar incision into the hind paw) and uninflamed (infraorbital nerve block) tissue in rats. Anaesthetic formulations (0.1ml) were injected near the right infraorbital foramen in uninflamed tissue, where success and duration of anaesthesia were assessed by pinching the upper lip every 5 minutes. For inflamed tissue the anaesthetic formulations (0.1ml) were injected laterally into a surgical wound made 24 hours earlier in the plantar region of the rat's right hind paw. The degree of anaesthesia was assessed by application of forces laterally to the wound with electronic von Frey filaments. Articaine:uni resulted in less successful anaesthesia than both articaine:multi (p=1.1x10(-5)) and articaine:epinephrine (p=4.3x10(-8)) in uninflamed tissue, but there were no differences in duration or success of anaesthesia between articaine:epinephrine and articaine:multi. In inflamed tissue articaine:epinephrine gave significantly more effective anaesthesia for longer than articaine:uni (p=2.3x10(-6)), and articaine:epinephrine (p=1.8x10(-6)) formulations, which did not differ from each other. Multilamellar liposomal articaine could be an option for local anaesthesia in uninflamed tissues. However, articaine with epinephrine gave better results than liposomal formulations in inflamed tissue.

Efficacy and Safety of 2% and 4% Articaine for Lower Third Molar Surgery

This double-blind crossover randomized clinical trial compared the efficacy of 2 concentrations of articaine, 2% (A2) and 4% (A4), with 1:200,000 epinephrine, for lower third molar removal. During 2 separate appointments with either A2 or A4, both similarly positioned lower third molars in 46 volunteers were extracted. The following were evaluated: onset and duration of anesthetic action on soft tissues, intraoperative bleeding, hemodynamic parameters, postoperative analgesia, and mouth opening and wound healing during the 7th postoperative day, along with the incidence, type, and severity of adverse reactions. Nearly identical volumes of both anesthetic solutions were used for each appointment: 3.4 ± 0.9 mL ≈ 68 mg of articaine (A2) and 3.3 ± 0.8 mL ≈ 132 mg of articaine (A4). Statistical analysis indicated no differences in onset or duration of anesthetic action on soft tissues or duration of postoperative analgesia evoked by A2 and A4 anesthetic solutions (P > 0.05). The surgeon's rating of intraoperative bleeding was considered minimal throughout all surgery with both anesthetic solutions. While transient changes in blood pressure, heart rate, and oxygen saturation were observed, these factors were clinically insignificant and were uninfluenced by articaine concentration (P > 0.05). No systemic or local adverse reactions were observed in the preoperative and postoperative periods due to A2 or A4, but 1 case of bilateral paresthesia was observed. There were no significant differences between preoperative and postoperative (7th day) values of mouth opening and wound healing whether volunteers received A2 or A4 (P > 0.05). In conclusion, both A2 and A4, administered in equal volumes, were effective and safe during lower third molar surgery, and no significant differences were found between their efficacy and safety (ClinicalTrials.gov NCT02457325).

Unusual Occurrence of Tongue Sensorial Disorder after Conservative Surgical Treatment of Lymphoepithelial Cyst

Lymphoepithelial cyst is a rare lesion of the oral cavity, with the mouth floor being the most common site of occurrence. The therapeutic approach of choice is the surgical treatment, which has rare cases of postoperative complications. The aim of this study is to report the case of a 53-year-old patient who came to Dental Service in the Federal University of Ceará complaining of a small nodular lesion (0.5 cm) located in the ventral tongue. Excisional biopsy was performed and the surgical specimen was submitted for anatomopathological analysis, which found that there was an oral lymphoepithelial cyst. The patient returned after seven days for suture removal and reported loss of sensitivity around the ventral tongue. We prescribed Citoneurin for ten days; however, there was not any significant improvement of the sensitivity. Low frequency laser therapy sessions were applied. The only postoperative symptom was dysesthesia, where there is only a sensitivity decrease. Currently, the patient has a postoperative period of 1 year without recurrence of the lesion. Although previous reports have no described tongue sensorineural disorders associated with this lesion, the occurrence of this event may be related to an unexpected anatomical variation of the lingual nerve.

Lingual Nerve Repair: To Graft or Not to Graft?

PURPOSE

Since no studies have compared direct and graft repair of the lingual nerve, we examined the subjective and objective outcomes of lingual nerve repair by direct epineurial repair and indirect graft repair, assessed the effect of other confounding variables, and compared the outcomes of autograft and allograft repairs.

PATIENTS AND METHODS

All patients who had undergone microneurosurgical repair of the lingual nerve from 2000 to 2012 by 1 surgeon (M.M.) were asked to complete an online questionnaire regarding their current neurosensory status at least 2 years after nerve repair. A direct comparison was made between patients who had undergone direct epineurial repair and those who had undergone interpositional nerve graft repair. Student's t test and χ(2) test were used to determine whether a significant difference existed in the success between the 2 techniques and whether age, gender, race, delay from injury to repair, or degree of initial nerve deficit influenced the success of nerve repair.

RESULTS

Of the 72 patients identified, 43, who had undergone 47 nerve repairs (18 direct, 29 indirect graft repairs [4 bilateral]; 28 female and 19 male patients; mean age 28.3 years), were interviewed. The objective results of functional sensory recovery, defined by a Medical Research Council Scale grade of S3, S3+, or S4, was 89% for the graft repairs and 85% for the direct repairs (P = .01). The subjective patient satisfaction score (0 to 10 scale) was 8.9 for the graft repairs and 8.1 for the direct repairs (P = .02). The autograft and allograft repairs performed comparably, and the other variables (ie, age, gender, race, delay from injury to nerve repair, gap length, and initial Sunderland grade injury) were not found to be significant (P > .05).

CONCLUSION

Graft repair of the lingual nerve provides superior long-term (>2 years) objective and subjective outcomes compared with direct repair. This might be because of the lack of tension at the repair site, more freedom with nerve stump preparation, and the addition of neurotropic and neurotrophic factors from the donor nerve graft at the site of injury to augment neurosensory recovery.

In vitro correlation of the level of inferior alveolar canal with CBCT imaging

PURPOSE

The aim was to correlate the level of the inferior alveolar canal on cadaver specimens and as evaluated with three-dimensional radiographic cone-beam computed tomography (CBCT) imaging.

METHODS

Twenty-one skulls with intact mandibles (42 inferior alveolar canals) were imaged with an I-CAT Cone-Beam 3D Imaging System and multi-planar reformatted images obtained were scored to assess the level of the canal (Level I, Level II, and Level III). The mandibles were later dissected and level of the canal was directly visualized, scored, and further correlated with results from CBCT imaging.

RESULTS

There was no difference in the level of the inferior alveolar canal between the dissected cadaver specimen and CBCT images. Also, there was no statistically significant difference in the level of the canal among the gender assigned to the specimens and corresponding CBCT images. There were no statistical differences in the level of the canal (cadaver specimen vs. CBCT) between the left and right sides of the specimens, as studied individually.

CONCLUSION

Our study indicates that there is close correlation of the level of the inferior alveolar canal between cadaver specimens and CBCT images. Well-designed studies would be required to further validate the findings in this study.

Diagnostic role of magnetic resonance imaging in assessing orofacial pain and paresthesia

The aim of this study was to compare the efficacy of CT and MRI in evaluating orofacial pain and paresthesia. A total of 96 patients with orofacial pain and/or paresthesia were included in this study. The patients who underwent CT and/or MRI examinations were assessed, and the efficacy of CT and/or MRI examinations in detecting the causative disease of the orofacial pain and paresthesia was evaluated. Seventy (72.9%) of 96 patients underwent CT and/or MRI examinations. Whereas CT examinations detected 2 diseases (4.5%) in 44 tests, 13 diseases (37.1%) were detected in 35 MRI examinations. Seven (53.8%) of 13 diseases, which were detected by MRI, were found in elderly patients. A high percentage of patients, who claimed orofacial pain and paresthesia, have other diseases in their brain, especially in elderly patients, and MRI is more useful than CT for evaluating these patients.

Efficacy and complications associated with a modified inferior alveolar nerve block technique. A randomized, triple-blind clinical trial

Objectives: To compare the efficacy and complication rates of two different techniques for inferior alveolar nerve blocks (IANB). Study Design: A randomized, triple-blind clinical trial comprising 109 patients who required lower third molar removal was performed. In the control group, all patients received an IANB using the conventional Halsted technique, whereas in the experimental group, a modified technique using a more inferior injection point was performed. Results: A total of 100 patients were randomized. The modified technique group showed a significantly higher onset time in the lower lip and chin area, and was frequently associated to a lingual electric discharge sensation. Three failures were recorded, 2 of them in the experimental group. No relevant local or systemic complications were registered. Conclusions: Both IANB techniques used in this trial are suitable for lower third molar removal. However, performing an inferior alveolar nerve block in a more inferior position (modified technique) extends the onset time, does not seem to reduce the risk of intravascular injections and might increase the risk of lingual nerve injuries.

Key words:Dental anesthesia, inferior alveolar nerve block, lidocaine, third molar, intravascular injection.

Adverse drug reactions in dental practice

Adverse reactions may occur with any of the medications prescribed or administered in dental practice. Most of these reactions are somewhat predictable based on the pharmacodynamic properties of the drug. Others, such as allergic and pseudoallergic reactions, are less common and unrelated to normal drug action. This article will review the most common adverse reactions that are unrelated to drug allergy.

Nanostructured guidance for peripheral nerve injuries: a review with a perspective in the oral and maxillofacial area

Injury to peripheral nerves can occur as a result of various surgical procedures, including oral and maxillofacial surgery. In the case of nerve transaction, the gold standard treatment is the end-to-end reconnection of the two nerve stumps. When it cannot be performed, the actual strategies consist of the positioning of a nerve graft between the two stumps. Guided nerve regeneration using nano-structured scaffolds is a promising strategy to promote axon regeneration. Biodegradable electrospun conduits composed of aligned nanofibers is a new class of devices used to improve neurite extension and axon outgrowth. Self assembled peptide nanofibrous scaffolds (SAPNSs) demonstrated promising results in animal models for central nervous system injuries, and, more recently, for peripheral nerve injury. Aims of this work are (1) to review electrospun and self-assembled nanofibrous scaffolds use in vitro and in vivo for peripheral nerve regeneration; and (2) its application in peripheral nerve injuries treatment. The review focused on nanofibrous scaffolds with a diameter of less than approximately 250 nm. The conjugation in a nano scale of a natural bioactive factor with a resorbable synthetic or natural material may represent the best compromise providing both biological and mechanical cues for guided nerve regeneration. Injured peripheral nerves, such as trigeminal and facial, may benefit from these treatments.

Estudo comparativo entre dois protocolos anestésicos envolvendo bloqueio do nervo alveolar inferior convencional e de Vazirani-Akinosi para exodontia de terceiro molar inferior

INTRODUÇÃO: O bloqueio do nervo alveolar inferior (BNAI) apresenta alta porcentagem de falha na Odontologia. A fim de melhorar esse índice, vêm-se estudando diferentes alternativas, como diferentes técnicas e soluções anestésicas. OBJETIVO: Avaliar duas diferentes técnicas - técnica convencional e de Vazirani-Akinosi - para o bloqueio do nervo alveolar inferior, bem como compará-las quanto à sua efetividade e quantificar o percentual de aspirações positivas nas duas diferentes técnicas. MATERIAL E MÉTODO: Foram avaliados 160 pacientes de ambos os sexos, sendo 80 submetidos ao bloqueio do nervo alveolar inferior de Vazirani-Akinosi e bloqueio do nervo bucal (G1), e 80 submetidos ao bloqueio do nervo alveolar inferior convencional e ao bloqueio do nervo bucal (G2). Em ambos os grupos, utilizou-se a combinação de articaína 4% com epinefrina 1:100.000 para bloqueio do nervo bucal, e lidocaína 2% com epinefrina 1:100.000 para bloqueio do nervo alveolar inferior. Foram avaliados: a quantidade de aspirações positivas, a eficácia da anestesia e o momento em que ocorreu a falha anestésica durante o procedimento cirúrgico. RESULTADO: Não houve diferenças estatisticamente significantes (p = 0,2453) entre os grupos G1 e G2 observando-se a eficácia e o índice de aspirações positivas, e o momento em que ocorreu a falha anestésica, observando-se uma maior eficácia de ambas as técnicas, quando comparadas com a literatura (90%) CONCLUSÃO: Não houve diferença significativa entre o BNAI pela técnica convencional e o BNAI pela técnica de Vazirani-Akinosi quanto a quantidade de aspirações positivas e eficácia, sendo que o uso da articaína 4% com epinefrina 1:100.000 no bloqueio do nervo bucal possivelmente aumentou a eficácia anestésica de ambas as técnicas.

Applied anatomy of the lingual nerve: relevance to dental anaesthesia

OBJECTIVES

(1) to classify the external morphology of the lingual nerve and investigate any relationship between its external and internal morphology, (2) to explore the fascicular structure, nerve tissue density and capillary density of the lingual nerve, and (3) to provide an anatomical explanation as to why adverse clinical outcomes more commonly affect the lingual nerve following local dental anaesthesia. Where possible, comparisons were made between the lingual and inferior alveolar nerves.

MATERIALS AND METHODS

The lingual and inferior alveolar nerves were examined in 23 hemi-sectioned heads macroscopically and microscopically 2mm above the lingula. The lingual nerve was also examined in the regions of the third and second molars. Specimens underwent histological processing and staining with Haematoxylin & Eosin, Masson's Trichrome, anti-GLUT-1 and anti-CD 34.

RESULTS

The lingual nerve became flatter as it traversed through the pterygomandibular space. There was an increase in the connective tissue and a decrease in nerve tissue density along the lingual nerve (p<0.001). At 2mm above the lingula, the lingual nerve was uni-fascicular in 39% of cases, whilst the inferior alveolar nerve consistently had more fascicles (p<0.001). The lingual nerve fascicles had thicker perineurium but the endoneurial vascular density was not significantly different in the two nerves.

CONCLUSIONS

The greater susceptibility of lingual nerve dysfunction during inferior alveolar nerve blocks may be due to its uni-fascicular structure and the thicker perineurium, leading to increased endoneurial pressure and involvement of all axons if oedema or haemorrhage occurs due to trauma.

An early and late cytotoxicity evaluation of lidocaine on human oral mucosa fibroblasts

Local anesthetic drugs are extensively used in dentistry. However, the cytotoxic effects of these pharmaceutical compounds remain unclear. In this work, we have evaluated the cell viability and cell function of human oral mucosa fibroblasts exposed to different concentrations of lidocaine for increasing incubation times, using a global screening methods including structural, metabolic and microanalytical analyses. Our results demonstrate that lidocaine is able to alter cell viability and function even at low concentrations and times, although the effect of lidocaine concentration was more important than the incubation time. First, the structural analysis methods revealed that ≥5% concentrations of lidocaine are able to significantly reduce cell viability. Then, the metabolic 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and water-soluble tetrazolium salt (WST-1) assays suggest that concentrations starting from 1% were able to significantly hinder cell physiology. Finally, electron-probe X-ray microanalysis confirmed the deleterious effects of lidocaine and allowed us to demonstrate that these effects are associated to an apoptosis process of cell death. Therefore, care should be taken when lidocaine is clinically used, and the lowest efficient concentrations should always be used. Furthermore, these results suggest that the comprehensive evaluation method used in this work is accurate and efficient for screening of local anesthetics.

Methemoglobin levels in generally anesthetized pediatric dental patients receiving prilocaine versus lidocaine

The purpose of this study was to measure and compare peak methemoglobin levels and times to peak methemoglobin levels following the use of prilocaine and lidocaine in precooperative children undergoing comprehensive dental rehabilitation under general anesthesia. Ninety children, 3-6 years of age, undergoing dental rehabilitation under general anesthesia were enrolled and randomly assigned into 3 equal groups: group 1, 4% prilocaine plain, 5 mg/kg; group 2, 2% lidocaine with 1:100,000 epinephrine, 2.5 mg/kg; and group 3, no local anesthetic. Subjects in groups 1 and 2 were administered local anesthetic prior to restorative dental treatment. Methemoglobin levels (SpMET) were measured and recorded throughout the procedure using a Masimo Radical-7 Pulse Co-Oximeter (Masimo Corporation, Irvine, Calif, RDS-1 with SET software with methemoglobin interface). Data were analyzed using chi-square, one-way analysis of variance (ANOVA), and Pearson correlation (significance of P < .05). Group 1 had a significantly higher mean peak SpMET level at 3.55% than groups 2 and 3 at 1.63 and 1.60%, respectively. The mean time to peak SpMET was significantly shorter for group 3 at 29.50 minutes than that of group 1 at 62.73 and group 2 at 57.50 minutes. Prilocaine, at 5 mg/kg in pediatric dental patients, resulted in significantly higher peak SpMET levels than lidocaine and no local anesthetic. In comparison to no local anesthetic, the administration of prilocaine and lidocaine caused peak SpMET levels to occur significantly later in the procedure.

Effect of articaine on mental nerve anterior portion: histological analysis in rats

OBJECTIVES

The aim of this study was to evaluate the possible toxic effects of articaine and lidocaine on mental nerve, due to the increasing number of paresthesia cases after nerve blocks.

MATERIALS AND METHODS

The drugs were injected in the anterior portion of mental nerve of 24 rats, divided into three groups: G1--4% articaine with 1:100,000 epinephrine; G2--2% lidocaine with 1:100,000 epinephrine and G3--plain 1:100,000 epinephrine solution. These solutions were injected in the right side of the rat's mandible and the left side was used as control (0.9% saline solution). Previously to the injections, the animals were anesthetized with thiopental and, 24 h after the injections, their jaws were removed and submitted to routine histological techniques. A histopathological analysis was performed by optical microscopy.

RESULTS

An inflammatory infiltration was found around mental nerve, classified as intense for G3, moderate for G1 and light for both G2 and control groups. No injuries were found in nervous structure, despite the inflammatory reaction observed around it.

CONCLUSION

The results suggest that articaine is not toxic to the nervous structure and further studies are necessary to explain the possible relation between articaine injection and paresthesia.

Hypoesthesia after IAN block anesthesia with lidocaine: management of mild to moderate nerve injury

Hypoesthesia after an inferior alveolar nerve (IAN) block does not commonly occur, but some cases are reported. The causes of hypoesthesia include a needle injury or toxicity of local anesthetic agents, and the incidence itself can cause stress to both dentists and patients. This case presents a hypoesthesia on mental nerve area followed by IAN block anesthesia with 2% lidocaine. Prescription of steroids for a week was performed and periodic follow up was done. After 1 wk, the symptoms got much better and after 4 mon, hypoesthesia completely disappeared. During this healing period, only early steroid medication was prescribed. In most cases, hypoesthesia is resolved within 6 mon, but being aware of etiology and the treatment options of hypoesthesia is important. Because the hypoesthesia caused by IAN block anesthesia is a mild to moderate nerve injury, early detection of symptom and prescription of steroids could be helpful for improvement of the hypoesthesia.

Local anesthetics: review of pharmacological considerations

Local anesthetics have an impressive history of efficacy and safety in medical and dental practice. Their use is so routine, and adverse effects are so infrequent, that providers may understandably overlook many of their pharmacotherapeutic principles. The purpose of this continuing education article is to provide a review and update of essential pharmacology for the various local anesthetic formulations in current use. Technical considerations will be addressed in a subsequent article.

Sensibility and taste alterations after impacted lower third molar extractions. A prospective cohort study

Objectives: To determine the incidence, severity and duration of lingual tactile and gustatory function impairments after lower third molar removal. Study Design: Prospective cohort study with intra-subject measures of 16 patients undergoing lower third molar extractions. Sensibility and gustatory functions were evaluated in each subject preoperatively, one week and one month after the extraction, using Semmes-Weinstein monofilaments and 5 different concentrations of NaCl, respectively. Additionally, all patients filled a questionnaire to assess subjective perceptions. Results: Although patients did not perceive any sensibility impairments, a statistically significant decrease was detected when Semmes-Weinstein monofilaments. This alteration was present at one week after the surgical procedure and fully recovered one month after the extraction. There were no variations regarding the gustatory function. Conclusions: Lower third molar removal under local anesthesia may cause light lingual sensibility impairment. Most of these alterations remain undetected to patients. These lingual nerve injuries are present one week after the extraction and recover one month after surgery. The taste seems to remain unaffected after these procedures.

Key words:Lingual nerve, third molar, nerve injury, paresthesia, surgical extraction

Dentists' perceptions of a new local anaesthetic drug--articaine

BACKGROUND

Articaine is a new local anaesthetic drug introduced to the Australian dental market. The aim of this study was to elicit information regarding the use of articaine in Australia, and factors that influence attitudes towards adoption of new technology.

METHODS

A self-administered postal questionnaire was sent to a stratified systematic sample of dentists who were members of the Australian Dental Association, with questions regarding details about articaine use and how influences such as education and scientific literature affect their adoption of new technology.

RESULTS

Of the sample, 53% responded and over 70% of dentists surveyed used articaine, with 95% and 97% of respondents identifying scientific literature and continuing professional development courses respectively as influencing factors in their adoption of new technology. The most common reason for not using articaine was no perceived advantage and the most influential factor that would encourage non-users to start using articaine was a scientifically proven advantage. Senior clinicians, specialists and public sector dentists were less likely to use articaine.

CONCLUSIONS

A majority of Australian dentists were using articaine and cited continuing professional development courses, scientific literature and anecdotal peer reports as being influential in their adoption of new technology.

Concentration-dependent neurotoxicity of articaine: an electrophysiological and stereological study of the rat sciatic nerve

BACKGROUND

We performed this study to quantify the detrimental effect of intraneural injection of 50 μL of saline, articaine 2%, or articaine 4% in the rat sciatic nerve.

METHODS

Lumbar-evoked electrospinograms from stimulation of the sciatic nerve were recorded before and immediately after injection and again after 3 weeks. Test substance was injected into the right sciatic nerve, and the untreated left sciatic nerve served as control. The animals were killed after the 3-week follow-up, and cross-sections of the sciatic nerve were examined stereologically.

RESULTS

The evoked spinal cord field potential in the articaine groups faded away immediately after injection and was concentration-dependently, significantly more reduced at the 3-week follow-up in comparison with the saline group. The response from the control sides was unaffected in all groups. The number of myelinated axons was unaffected by the treatment. The mean cross-sectional axon area and the mean myelin sheath thickness were significantly reduced in animals injected with articaine 4%.

CONCLUSIONS

These observations indicate concentration-dependent neurotoxic injuries after injection of articaine with a significant difference between 2% and 4% formulations. The mechanical injury of needle penetration with saline injection had no significant effect on nerve conduction or histomorphology.

Medico-legal aspects of altered sensation following endodontic treatment: a retrospective case series

OBJECTIVE

The objective of this study was to analyze cases of liability claims related to persistent altered sensation following endodontic treatments so as to characterize the medico-legal aspects of this complication.

STUDY DESIGN

A comprehensive search of an Israeli professional liability insurance database was conducted to retrospectively identify and analyze cases of persistent altered sensation following endodontic treatment.

RESULTS

Sixteen claims of persistent altered sensation following endodontic treatments were identified and analyzed. The typical profile of a claim was a female patient who underwent an endodontic treatment at a second mandibular molar, which was associated with overfilling. A significant correlation between the tooth location and the suggested cause of nerve injury was found. None of the claims were reported by the practitioners, and all cases were identified as a result of the patient's demand for financial compensation, either directly or by legal actions.

CONCLUSIONS

When a nerve injury is diagnosed, the treating practitioner should be encouraged to seek medical and legal assistance so as to prevent permanent damage and to enable a better medico-legal response.