Anaesthetic efficacy of incorporating different additives into lidocaine for the inferior alveolar nerve block: A systematic review with meta-analysis and trial sequential analysis.

BACKGROUND: Incorporating an additive into lidocaine is a method to enhance the efficacy of the inferior alveolar nerve block (IANB) in mandibular posterior teeth. OBJECTIVES: To assess the efficacy of incorporating additives into lidocaine in the success rate of IANB for teeth with the diagnosis of normal pulp (NP) or symptomatic irreversible pulpitis (SIP). METHODS: Randomized controlled trials (RCTs) assessing the incorporation of additives into lidocaine on the pulpal anaesthesia success rate of mandibular posterior teeth were searched in PubMed, Scopus, Web of Science, Ovid, EBSCO, Embase, and Cochrane databases up to 1 December 2021. The risk of bias (RoB) was assessed by the Cochrane Risk of Bias Tool. A random-effects model was employed to calculate the pooled risk ratio (RR) with a 95% confidence interval (CI), using STATA 16. The trial sequential analysis (TSA) was applied to calculate the required information size (RIS). The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach was used to assess the certainty of the evidence. RESULTS: Of 6966 records retrieved initially, 14 trials (8 for NP and 6 for SIP groups) were included in qualitative and quantitative syntheses. All trials were categorized as low and unclear RoB for NP and SIP groups, respectively. In the NP group, with 307 participants, no significant effect was observed for additives incorporated into lidocaine (RR: 0.84; 95% CI: 0.53-1.32; I2  = 98%). Subgroup analysis revealed that adding mannitol led to a higher success rate (RR = 1.24; 95% CI: 1.15-1.34; I2  = 7.16%). In the SIP group, with 434 participants, no significant effect was shown when the additives were incorporated (RR = 1.22; 95% CI: 0.98-1.52; I2  = 0%). Likewise, in subgroup analysis, incorporating mannitol or sodium bicarbonate demonstrated no significant effect (RR = 1.76; 95% CI: 0.93-3.32; I2  = 18.41% and RR = 1.06; 95% CI: 0.65-1.72; I2  = 53.5%, respectively). DISCUSSION: TSA revealed that the outcome was "inconclusive" for each group. The certainty of the evidence was graded as "very low" and "low" for NP and SIP groups, respectively. CONCLUSIONS: The very low to low certainty of evidence indicated that incorporating additives into lidocaine did not increase the efficacy of IANB and supplemental injections are still necessary to help practitioners achieve painless dentistry. REGISTRATION: PROSPERO database (CRD42020132585).

Anaesthetic efficacy of 2% lidocaine with different concentrations of epinephrine (1:80,000 and 1:200,000) in intraligamentary injection after a failed primary inferior alveolar nerve block: a randomized double-blind study.

Introduction: The present study evaluated the anaesthetic efficacy of 2% lidocaine with 1:80,000 epinephrine vs. 2% lidocaine with 1:200,000 given as supplemental intraligamentary injections after a failed inferior alveolar nerve block (IANB) in patients with symptomatic irreversible pulpitis. The effect of these solutions on the heart rate was also evaluated.Methods: One-hundred-eighteen adult patients with symptomatic irreversible pulpits in a mandibular first or second molar, received an initial IANB with 2% lidocaine with 1:80,000 epinephrine. Pain during the endodontic treatment was assessed using a visual analogue scale (Heft-Parker VAS). Eighty-eight patients with unsuccessful anaesthesia were randomly allocated to one of the two treatment groups: one group received 0.6 mL/root of supplementary intraligamentary injection of 2% lidocaine with 1:80,000 epinephrine; while the second group received 2% lidocaine with 1:200,000 epinephrine. Endodontic treatment was re-initiated. Success after primary injection or supplementary injection was defined as no or mild pain (pain score ≤54 mm on HP VAS) during access preparation and root canal instrumentation. Heart rate was monitored using a finger pulse oximeter. The anaesthetic success rates were analyzed with the Pearson chi-square test at 5% significance levels. The heart rate changes were analyzed using the t-test.Results: The anaesthetic success rate in patients receiving supplementary intraligamentary injections in 1:80,000 epinephrine group was 82%, while the intraligamentary injections with 2% lidocaine with 1:200,000 epinephrine were successful in 57% of cases. The difference was statistically significant (χ2=6.4, p = .011). There was no significant effect of both the anaesthetic agents on the mean heart rate.Conclusions: Both 2% lidocaine with 1:80,000 epinephrine and 2% lidocaine with 1:200,000 epinephrine improved the success rates after a failed primary anaesthetic injection. The 1:80,000 epinephrine group was significantly more successful.

Effect of Three Different Injection Sites on the Success of Anterior Middle Superior Alveolar Nerve Block with 3% Mepivacaine: A Randomized Controlled Trial.

AIM: Anterior middle superior alveolar (AMSA) nerve block injection targets the anterior superior alveolar nerve and the middle superior alveolar nerve branches of the infraorbital nerve through nutrient canals. Therefore, the central incisor to the second premolar teeth of one quadrant can be anesthetized. The aim of the present study was to evaluate the efficacy of AMSA nerve block injection with 3% mepivacaine solution at three different injection sites. MATERIALS AND METHODS: In a double-blind crossover study, 47 volunteers participated and three AMSA nerve block injections of 3% mepivacaine solution without epinephrine were administered at the anterior, posterior, and the most common injection sites with a 1-week interval between injections. Anesthesia of the central incisor to the second premolar of the injected side was evaluated by using an electric pulp tester. The success of the injection was considered as lack of response to two consecutive 80 readings. The generalized estimating equation analytic tests were administered (α = 0.05). RESULTS: The success rate of the AMSA nerve block injection ranged from 27.5-47.5% for the most common injection site and 22.5-42.5% for both the anterior and posterior injection sites. CONCLUSION: Changing the injection site did not result in statistically significant improvements (p > 0.05). CLINICAL SIGNIFICANCE: Changing the injection site anteropos-teriorly did not influence the success rate of the AMSA nerve block injection.

Influence of tooth length on the accuracy of the Root ZX electronic apical foramen locator: an ex vivo study.

OBJECTIVE: Electronic apical foramen locators are now widely used to determine working length. This study was designed to determine whether tooth length influenced the accuracy of the Root ZX device. MATERIALS AND METHODS: Forty extracted maxillary canine teeth with a length range of 27-29 mm were selected. Access cavities were prepared and coronal flaring of canals performed. The teeth were mounted in self-polymerizing acrylic resin to facilitate horizontal sectioning except for the apical 3-4-mm portion of the root and embedded in alginate as the electronic medium. Electronic measurements were taken at the major foramen, 'zero' reading using the Root ZX and compared with the actual root canal length. The teeth were sectioned 3 mm from the coronal reference point to create a second group with shorter length; these reductions in the length continued six times in all to create seven groups of 40 specimens each. The actual and electronic lengths of specimens in each group were measured. Data were analyzed by Pearson's correlation coefficient. RESULTS: Identical measurements between the actual and electronic root canal length from the longest to the shortest groups were 12.5%, 10.0%, 20.0%, 27.5%, 37.5%, 35.0% and 45.0%, respectively. There was a mild negative correlation between the precise measurements of the Root ZX and root canal lengths in the seven groups (r = -0.964, p < 0.001). CONCLUSION: Under the conditions of the study, the Root ZX device was more accurate in shorter teeth compared to longer ones.

Evaluation of apical transportation and centering ability of three single-file systems in severely curved canals using micro-computed tomography.

Background: This study aimed to compare the apical transportation and centering ability of One Curve, HyFlex EDM, and EdgeFile X1 in curved mesiobuccal and mesiolingual canals of mandibular first molars. Materials and Methods: In this in vitro experimental study, 60 mesiobuccal and mesiolingual canals of the mandibular first molars with a minimum length of 19 mm and 25°-40° curvature were randomly divided into three groups (n = 20) for root canal preparation with One Curve, HyFlex EDM, and EdgeFile X1. After access cavity preparation and confirming the glide path, the baseline micro-computed tomography (micro-CT) scans were obtained, and the root canals were instrumented with the respective systems according to the manufacturers' instructions. Apical transportation and centering ability were assessed at 1, 3, 5, and 7 mm from the apex by comparing pre- and postinstrumentation micro-CT scans. One-way ANOVA, independent t-test, and Duncan's post hoc test were used to statistically compare the groups, and data were analyzed by SPSS version 24 (alpha = 0.05). Results: The three groups were not significantly different regarding apical transportation at 5 and 7 mm from the apex (P > 0.05). At 1 mm level, One Curve caused significantly lower apical transportation; while, at 3 mm level, HyFlex EDM resulted in significantly higher apical transportation (P < 0.05). No significant difference was noted in the centering ability of the three groups at 1, 3, and 5 mm from the apex (P > 0.05). At 7 mm level, EdgeFile X1 showed significantly lower centering ability (P < 0.05). Conclusion: One Curve caused lower canal transportation in the apical third compared with EdgeFile and HyFlex EDM, but no significant difference was noted among the three in the coronal third of the roots.

Effect of Intraligamentary Tramadol Hydrochloride on Anesthetic Success During Endodontic Management of Mandibular Molars: A Randomized Clinical Controlled Trial.

OBJECTIVE: Tramadol hydrochloride has shown local anesthetic properties similar to lidocaine, apart from a central analgesic effect. The present study evaluated the effect of the administration of tramadol alone or in addition to 2% lidocaine, as supplementary intraligamentary injections. METHODS: One hundred and five patients, with a failed primary inferior alveolar nerve block (IANB), were randomly allocated to one of the three supplementary intraligamentary groups: 2% lidocaine with 1: 80,000 epinephrine; tramadol hydrochloride (50 mg/mL); and 2% lidocaine with 1: 80,000 epinephrine plus tramadol hydrochloride. Patients received 1.2 mL doses (0.6 mL of each root). Patients reporting pain ≤54 on Heft Parker visual analogue scale (Heft-Parker VAS), were categorized as successful anesthesia. A finger pulse oximeter was used to measure the heart rates. The anesthetic success rates, gender, and type of tooth were compared using the Pearson chi-square test. The heart rates and age were statistically evaluated using the one-way analysis of variance test. The level of significance was set at 0.05 (p=0.05). RESULTS: The initial IANB was successful in 31% of cases. There were significant differences in the anesthetic success rates of different supplementary intraligamentary injections (χ2= 33.6, p<0.001, df=2). The 2% lidocaine-plus-tramadol resulted in significantly higher success rates than the two groups. There were no significant changes in the baseline heart rates of all groups (p>0.05). CONCLUSION: The addition of tramadol to 2% lidocaine with 1: 80,000 epinephrine, given as supplementary intraligamentary injection, can help in achieving successful anesthesia during the endodontic management of mandibular molars with irreversible pulpitis resistant to IANB injections.

Effect of Back-Pressure Anesthesia on Postoperative Pain after the Endodontic Treatment in Patients with Symptomatic Irreversible Pulpitis: Randomized Double-Blind Clinical Trial.

INTRODUCTION: The present study evaluated the effect of 2 different back pressure-based supplemental anesthesia on postoperative pain in patients receiving endodontic treatment for a mandibular molar with symptomatic irreversible pulpitis. METHODS: One-hundred-thirty-five adult patients with symptomatic irreversible pulpits in a mandibular first or second molar, received an initial inferior alveolar nerve block (IANB) injection with 2% lidocaine with 1:80,000 epinephrine. Ten minutes following the injection, access to cavity preparation began. Lip numbness was a must for all patients. The Heft-Parker visual analogue scale (HP-VAS) was used to measure pain during endodontic therapy. Success of primary injections was defined as no or mild pain (less than 55 mm on HP-VAS) during access preparation. The patients with initial successful anesthesia served as control and received endodontic treatment. Ninety-five patients with unsuccessful primary anesthesia randomly received either intraligamentary injections of 2% lidocaine with 1:80,000 epinephrine or intrapulpal injections with similar anesthetic solution. Endodontic treatment was re-initiated and canals were instrumented till working length under copious irrigation. Intracanal medicament of calcium hydroxide was placed and teeth received a temporary restoration. Postoperative pain was measured at 2 hours, 4 hours, 6 hours, 24 hours, and 3 days. Data were analyzed using the Pearson chi-square test, one-way analysis of variance, and one-way repeated measures analysis of variance. RESULTS: The initial initial inferior alveolar nerve block was successful in 40 cases (out of 135). The intraligamentary injections were successful in 33 out of 47 cases (70%), and intrapulpal injections were successful in all cases (45/45). The patients receiving intraligamentary injections reported significantly higher pain scores at all intervals till 24 hours. After 3 days, the pain significantly reduced in all the groups with no significant difference between them. CONCLUSIONS: Patients receiving supplementary intraligamentary injections can experience increased postoperative pain till 24 hours after the endodontic treatment. The pain scores reduced to the level of the control group after 3 days.

Evaluation of the Fracture Resistance of Conservative and Ultraconservative Access Cavity Designs with Different Treatment Modalities: An In Vitro Study.

Introduction: The aim of this study was to evaluate the fracture resistance of endodontically treated mandibular molars using traditional and conservative access cavity preparation. Materials and Methods: In this in vitro study, 100 extracted healthy human mandibular molars were selected and divided into 10 groups (n = 10). Healthy teeth in one group were considered the control group. In three groups, traditional access cavity preparation was done (groups A) without two marginal ridges (A1), with one marginal ridge (A2), and with two marginal ridges (A3). In three groups (group B), two separate access cavities with a dentinoenamel roof without two marginal ridges (B1), with one marginal ridge (B2), and with two marginal ridges (B3) were prepared. In three other groups (groups C), two separate access cavities were prepared only with a dentinal roof without two marginal ridges (C1), with one marginal ridge (C2), and with two marginal ridges (C3), on which root canal treatment was performed afterward. Then, these teeth were subjected to force until fracture. The fracture force and fracture mode of each tooth were recorded and compared between groups by ANOVA, Tukey's post hoc, and chi-square tests using SPSS ver. 23 (IBM, Somers, NJ, USA). Results: The control teeth had the highest mean fracture force (2804.5 ± 338.5 N), followed by a conservative access cavity with a dentinoenamel roof and two marginal ridges (2360.4 ± 181.72 N) and a conservative access cavity with a dentinoenamel roof and one marginal ridge (1812.8 ± 263.9 N), respectively. The lowest mean fracture force was found for the conventional access cavity group without two marginal ridges (399.4 ± 95.2 N). Conclusion: In the condition of this study, with two separate access cavities in mandibular molars and maintenance of the marginal ridges, it is possible to provide teeth with higher fracture resistance against occlusal forces.

Effect of local anesthetics on renal function: An animal study in Iran.

Background: Although most of the metabolism of local anesthetics (LAs) takes place in the liver, no study has investigated the effect of these anesthetics on the kidney function of single-kidney humans or animals. The present study was conducted to examine the effect of LAs on renal function in single-kidney rats. Materials and Methods: The present experimental animal study with two control groups was done in an animal laboratory. Forty-two rats were randomly assigned to seven groups of six rats, including two control groups and five experimental groups. The experimental groups underwent intraperitoneal anesthesia with 2% lidocaine, 2% lidocaine with 1:80,000 epinephrine, 4% articaine, 3% prilocaine with 0.03 IU Felypressin, and 3% mepivacaine, respectively. Unilateral nephrectomy was done. After 24 h, the rats' blood urea nitrogen (BUN), serum creatinine (Cr), and blood specific gravity (BSG) were measured. A standard dose of anesthetics was injected into the peritoneum for 4 days afterward. Then, these indices were measured again 24 h after the last injection. Data were analyzed using IBM SPSS (version 21.0). One-way analysis of variance, Tukey's honestly significant difference post hoc, and paired t-tests were used for statistical analysis. P < 0.05 was considered statistically significant. Results: The results indicated significant differences among groups in the rats' BUN and serum Cr 24 h after nephrectomy (P < 0.05). However, there were no significant differences in BUN, BSG, and Cr among groups after the interventions. Conclusion: LAs did not affect renal function in single-kidney rats. Therefore, dentists can use the anesthetics in single-kidney people.

Effect of Cooling of Lidocaine with Epinephrine on the Anesthetic Success of Supplementary Intraligamentary Injection after a Failed Primary Inferior Alveolar Nerve Block: A Randomized Controlled Trial.

OBJECTIVE: The purpose of this prospective, randomized clinical trial was to evaluate the effect of cooling a 2% lidocaine solution with 1: 200,000 epinephrine, administered as a supplementary intraligamentary injection to overcome a failed primary inferior alveolar nerve block (IANB). METHODS: The study was preceded by a pilot study to evaluate the anesthetic efficacy of plain lidocaine solutions given as intraligamentary injections. In the subsequent randomized clinical trial, one hundred and thirty-eight patients received IANB with 2% lidocaine with 1: 80,000 epinephrine for endodontic man- agement of a mandibular molar with symptomatic irreversible pulpitis. Eighty-eight patients reported pain greater than 54 mm on a visual analog scale (Heft-Parker VAS) were categorized as unsuccessful anesthesia. These patients received either of the following intraligamentary injections: 2% lidocaine with 1: 200,000 epinephrine at room temperature; or 2% lidocaine with 1: 200,000 epinephrine at 4°C. Anes- thetic success was again evaluated after re-initiation of the endodontic treatment. The heart rates of the patients were measured using a finger pulse oximeter. The categorical success rates were statistically analyzed with the Pearson chi-square test at 5% significance levels. The heart rate measurements were analyzed using a t-test. RESULTS: The intraligamentary injections with anesthetic solutions at room temperature presented a suc- cess rate of 59.1%, while the injections with a solution at 4°C gave a success rate of 52.27%. There were no significant differences between the success rates of the groups (χ2=0.41, p=0.52). Regarding the heart rates, there were no differences between the two solutions at baseline (T=1.2, p=0.2) or after injections (T=0.64, p=0.52). CONCLUSION: Reducing the temperature of 2% lidocaine with 1: 200,000 epinephrine to 4°C does not affect the anesthetic efficacy of supplemental intraligamentary injections, given after a failed primary IANB. (EEJ-2023-03-044).

Erratum: Addendum: Addition of 2 mg dexamethasone to improve the anesthetic efficacy of 2% lidocaine with 1:80,000 epinephrine administered for inferior alveolar nerve block to patients with symptomatic irreversible pulpitis in the mandibular molars: a randomized double-blind clinical trial.

[This corrects the article on p. 305 in vol. 22, PMID: 35991360.].

The effect of various concentrations of iodine potassium iodide on the antimicrobial properties of mineral trioxide aggregate--a pilot study.

BACKGROUND: Mineral trioxide aggregate (MTA) is a multi-purpose dental material with various uses in dentistry. Iodine potassium iodide (IKI) is the most commonly used iodine compound in endodontics. We aimed to assess the antimicrobial activity of tooth-colored ProRoot MTA combined with IKI. MATERIALS AND METHODS: The antimicrobial activity of IKI was assessed at three concentrations (1%, 2%, and 4%) as the mixing agents combined with MTA against Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. For each microorganism, three plates were inoculated with 100 µl of a microbial suspension (McFarland 0.5). Four wells were prepared in each plate. MTA (70 mg) was mixed with any of the three concentrations of IKI (25 µl) or sterile distilled water (25 µl) and placed in each well. The plates were incubated for 24 h at 37°C. Zones of inhibition (ZOI) were measured in millimeters by a blinded observer. Data were analyzed using analysis of variance and the Dunnett t-test. RESULTS: All MTA mixtures with water or IKI solutions showed inhibitory zones. The mean ZOI of each MTA/IKI mixture was not significantly different from MTA/water mixture (P > 0.05). MTA/1% IKI had smaller ZOI than MTA/water against E. coli, E. faecalis, and C. albicans. MTA/2% IKI showed larger ZOI only against P. aeruginosa. MTA/4% IKI showed larger ZOI against P. aeruginosa and E. coli (P < 0.05). CONCLUSIONS: Substitution of IKI solutions (1%, 2%, and 4%) for water did not significantly increase the antimicrobial activity of MTA.

Effect of Citric Acid Versus EDTA on Radiographic Root Development in Regenerative Endodontic Treatment: An Animal Study.

INTRODUCTION: Regenerative endodontic treatment was introduced with the aim of reinforcing the root and enabling further root development. In the process of dentin mineralization, bioactive molecules are entrapped in the dentin matrix, which can be released later by rinsing the dentin with chelating agents. This study aimed to compare the effects of citric acid and EDTA on radiographic root development in regenerative endodontic treatment in an animal model. METHODS: Premolars of 3 beagle dogs were used in this study. The teeth at 1 side of the jaw were irrigated with EDTA according to the regeneration protocol of the American Association of Endodontists. The teeth in the other quadrant were irrigated with citric acid in the second treatment session. Follow-up radiographs were obtained at 6 months, and the primary and final data were analyzed in SPSS Version 23 (IBM Corp, Armonk, NY) using the analysis of covariance. RESULTS: There was no significant difference between the 2 irrigating solutions regarding the increase in root length (P = .668); however, EDTA showed significantly superior efficacy in increasing the root dentin thickness compared with citric acid (P = .022). CONCLUSIONS: Within the limitations of this study, the use of citric acid versus EDTA was not superior on radiographic root development in regenerative endodontic treatment.

In Vitro Diagnostic Accuracy and Agreement of Dental Microscope and Cone-Beam Computed Tomography in Comparison with Microcomputed Tomography for Detection of the Second Mesiobuccal Canal of Maxillary First Molars.

Objectives: The percentage of failure of endodontically treated maxillary molars is relatively high; one main reason is that the second mesiobuccal canal (MB2) is missing. Some techniques have been proposed for detection of the MB2. This study was aimed at assessing the diagnostic accuracy and agreement of the dental microscope and cone-beam computed tomography (CBCT) in comparison with microcomputed tomography (micro-CT) for detection of the MB2 of maxillary first molars in vitro. Materials and Methods: This in vitro, experimental study evaluated 71 permanent maxillary first molars that were stored in 100% humidity at room temperature. The teeth were mounted in 9 silicone dental arches to the level of their cementoenamel junction (8 teeth in each arch). The blocks underwent CBCT in a XG3D scanner. Access cavity was then prepared, and the teeth were inspected by a surgical microscope for negotiation of the MB2. Also, micro-CT images were obtained from the teeth to serve as the gold standard. CBCT and micro-CT images were observed by two examiners twice with a 2-week interval. Results: The frequency of the MB2 detected by dental microscope was significantly lower than micro-CT (P < 0.001) and CBCT (P = 0.008); no significant difference existed between micro-CT and CBCT in this respect. The sensitivity, specificity, positive predictive value, and negative predictive value of CBCT for detection of MB2 were 92.6%, 100%, 100%, and 81%, respectively. Conclusion: CBCT is superior to the dental microscope for detection of the MB2 of maxillary first molars and can be used for this purpose in the clinical setting with adequate accuracy.

Addition of 2 mg dexamethasone to improve the anesthetic efficacy of 2% lidocaine with 1:80,000 epinephrine administered for inferior alveolar nerve block to patients with symptomatic irreversible pulpitis in the mandibular molars: a randomized double-blind clinical trial.

Introduction: This clinical trial aimed to evaluate the anesthetic effect of the addition of 2 mg (4 mg/ml) of dexamethasone to 2% lidocaine (plain or with 1:80,000 epinephrine). The solutions were injected for a primary inferior alveolar nerve block (IANB) to provide mandibular anesthesia for the endodontic treatment of mandibular molars with symptomatic irreversible pulpitis. Methods: In a double-blinded setup, 124 patients randomly received either of the following injections: 2% lidocaine with 1:80,000 epinephrine, 2% lidocaine with 1:80,000 epinephrine mixed with 2 mg dexamethasone, or plain 2% lidocaine mixed with 2 mg dexamethasone, which were injected as a primary IANB. Ten minutes after injection, patients with profound lip numbness underwent electric and thermal pulp sensibility tests. Patients who responded positively to the tests were categorized as "failed" anesthesia and received supplemental anesthesia. The remaining patients underwent endodontic treatment using a rubber dam. Anesthetic success was defined as "no pain or faint/weak/mild pain" during endodontic access preparation and instrumentation (HP visual analog scale score < 55 mm). The effect of the anesthetic solutions on the maximum change in heart rate was also evaluated. The Pearson chi-square test at 5% and 1% significance was used to analyze anesthetic success rates. Results: The 2% lidocaine with 1:80,000 epinephrine, 2% lidocaine with 1:80,000 epinephrine mixed with 2 mg dexamethasone, and plain 2% lidocaine mixed with 2 mg dexamethasone groups had anesthetic success rates of 34%, 59%, and 29%, respectively. The addition of dexamethasone resulted in significantly better results (P < 0.001, χ2 = 9.07, df = 2). Conclusions: The addition of dexamethasone to 2% lidocaine with epinephrine, administered as an IANB, can improve the anesthetic success rates during the endodontic management of symptomatic mandibular molars with irreversible pulpitis.

Effect of Duration of Root Canal Infection on the Ability of Dentin-Pulp Complex Regeneration of Immature Permanent Teeth: An Animal Study.

INTRODUCTION: Persistent infection is always considered the most important reason for the failure of dentin-pulp complex regeneration. The present study aimed to evaluate the effect of the duration of root canal infection (from 1-12 weeks) on the ability of dentin-pulp complex regeneration. METHODS: In this animal study, 64 roots of immature premolar teeth of 4 dogs were randomly divided into the following groups: the positive control group, 8 root canals treated with the regenerative endodontic procedure (REP); the negative control group, 12 infected root canals; the intervention groups, 36 root canals infected with supragingival plaque (1, 3, 6, and 12 weeks) and treated with REP; and an additional positive control group, 8 normal roots. After 3 months, the teeth were investigated by radiographic images and immunohistochemical staining (CD31, CD34, and S100 markers). In addition, DSPP gene expression was assessed using a real-time polymerase chain reaction technique. RESULTS: Based on radiologic evaluation among the intervention groups, the highest root canal development (length and width) occurred in the intervention group of 1 week, and the lowest radiologic results were in the intervention groups of 6 and 12 weeks (1-way analysis of variance, P-value < .05). There was a significant difference between the groups in terms of CD31, CD34, S100, and DSPP expression percentage (1-way analysis of variance, P-value < .05); the highest and lowest expression percentages belonged to the 1- and 12-week groups, respectively, among the intervention groups. CONCLUSIONS: This study demonstrated that long root canal infection decreased the ability of the body to regenerate the dentin-pulp complex.

Anesthetic Success Rate of Inferior Alveolar Nerve Block for Mandibular Molars with Symptomatic Irreversible Pulpitis in Women Taking Antidepressants.

Introduction: This study sought to evaluate the success rate of inferior alveolar nerve block (IANB) during the endodontic management of mandibular molars with symptomatic irreversible pulpitis in women taking selective serotonin reuptake inhibitor (SSRI) antidepressants. Materials and Methods: Ninety adult female patients over 18 years of age who were diagnosed with symptomatic irreversible pulpitis of a mandibular molar were recruited in this study. The patients were equally assigned to SSRI user group (including citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, and sertraline), who had taken an SSRI, and non-SSRI user group, who had not taken any SSRIs at all. All patients in both groups received 3.6 mL of 2% lidocaine with 1:80,000 epinephrine using conventional IANB injection. Access cavity was prepared 15 min after the injection. Lip numbness was necessary for all patients. Success was determined as no or mild pain upon access cavity preparation and/or instrumentation based on the Heft-Parker visual analog scale recordings. Data were analyzed using the chi-square test Mann-Whitney U test, and t-test. Results: The success rate was 55.6% for SSRI users and 44.4% for non-SSRI users, and no statistically significant difference was observed between the two groups (x 2=1.1, P=0.292). Conclusions: Based on the results of this study, taking SSRI antidepressants could not affect the anesthetic success rate of IANB for mandibular molars with symptomatic irreversible pulpitis in women.

Histological assessment of the local effect of different concentrations of aminoguanidine hydrochloride on bone healing in rats.

BACKGROUND: Nitric oxide (NO) has several functions in bone healing and affects bone metabolism. Selective inducible NO synthase (iNOS) inhibitors can be used to assess the efficacy of NO for healing of bone defects. This study sought to assess the local effect of different concentrations of aminoguanidine hydrochloride (AG), a selective iNOS inhibitor, on bone healing in rats. MATERIALS AND METHODS: In this animal experimental study, 72 rats were divided into six groups of control, placebo, 5% AG, 10% AG, 15% AG, and 20% AG. A bone defect measuring 5 mm × 5 mm was created in the femur. The defect remained empty in the control group. In the placebo group, neutral gel was placed in the bone defect, and in the remaining four AG groups, different concentrations of AG were applied to the defects. Bone healing was assessed histologically. The healing score in the six groups was analyzed by the Kruskal-Wallis test. A P < 0.05 was considered statistically significant. RESULTS: The healing score in 20%, 15%, 10%, and 5% AG groups was significantly higher than that in the neutral gel and control groups (P < 0.01). Among the four groups of AG, 20% concentration showed better results, but the difference was not significant. CONCLUSION: Four concentrations of AG caused greater bone healing compared to the other two groups. Selective iNOS inhibitors such as AG can be used to promote local bone healing.

Preoperative Intraligamentary Injection of Dexamethasone Can Improve the Anesthetic Success Rate of 2% Lidocaine during the Endodontic Management of Mandibular Molars with Symptomatic Irreversible Pulpitis.

INTRODUCTION: The aim of this randomized, double-blind clinical trial was to evaluate the effect of preoperative administration of intraligamentary injections of diclofenac sodium and dexamethasone on the anesthetic efficacy of 2% lidocaine given as an inferior alveolar nerve block in the endodontic management of symptomatic irreversible pulpitis. METHODS: One hundred seventeen patients randomly received 1 of the 3 intraligamentary injections before the endodontic treatment: 0.9% normal saline, 25 mg/mL diclofenac sodium, or 4 mg/mL dexamethasone. After 30 minutes, patients received an inferior alveolar nerve block with 2% lidocaine and 1:80,000 epinephrine. The teeth were tested with electric pulp testing after 10 minutes. In case of a positive response, the anesthesia was considered as "failed." If the electric test response was negative, a rubber dam was applied, and endodontic treatment was started. Any pain during the treatment was recorded. The anesthesia was considered successful if the patients experienced no pain or faint/weak/mild pain during root canal access preparation and instrumentation (Heft-Parker visual analog scale score <55 mm). The effect of intraligamentary injections on maximum heart rates was also recorded. The anesthetic success rates were analyzed with the Pearson chi-square test at 5% significance. RESULTS: The control, diclofenac sodium, and dexamethasone groups had anesthetic success rates of 32%, 37%, and 73%, respectively. Dexamethasone was significantly more successful than the control and diclofenac sodium groups (P < .001, χ22 = 14.7). There were no differences between the control and diclofenac groups (P > .05). All the solutions did not significantly affect heart rates. CONCLUSIONS: The administration of an intraligamentary injection of dexamethasone before endodontic intervention of mandibular molars with symptomatic irreversible pulpitis increases the success rates of an inferior alveolar nerve block with 2% lidocaine.

Evaluation of Antimicrobial Effcacy of Calcium Hypochlorite as an Endodontic Irrigant on a Mixed-Culture Biofilm: An Ex vivo Study.

Introduction: Calcium hypochlorite (CH) has been recently suggested as an endodontic irrigant. The aim of this investigation was to evaluate the antimicrobial efficacy of CH compared to sodium hypochlorite (NaOCl) and chlorhexidine (CHX) against multispecies biofilm in surface and deep dentinal tubules. Methods and Materials: Minimal inhibitory concentration (MIC) of irrigant agents was assessed using a microdilution method. One hundred and twenty of human maxillary incisor teeth were prepared and infected with suspension of Entrococcus faecalis, Fusobacterium nucleatum and Prevotella intermedia in an anaerobic jar for 7 days. Depending on irrigation solutions, specimens were divided into 4 groups (n=30); group 1: 2% CHX, group 2: 5.25% sodium hypochlorite, group 3: 5% calcium hypochlorite, group 4: positive control (normal saline (NS)). Fifteen remained specimens were used as negative control. Surviving bacteria were sampled before (S1) and after irrigation from surface (S2) and deep (S3) dentin. The medium turbidity was visualized with spectrophotometry. Data were analyzed using analysis of variance followed by Tukey post hoc test (α=0.05). Results: The MIC of CH against E. faecalis, F. nucleatum and P. intermedia was 25, 8 and 7.5 µg/mL respectively. There were no significant differences in S1 among the test groups. Moreover, 2% CHX and 5% CH had significantly lower medium turbidity at both S2 and S3, in comparison with 5.25% NaOCl (P=0.018 and 0.031, respectively). But there were no significant differences between 2% CHX and 5% CH at both S2 and S3 (P=0.862 and 0.978, respectively). Conclusion: Under the conditions of this ex vivo study, 5% CH and 2% CHX are more effective than 5.25% NaOCl in the reduction of mixed-culture biofilm.