A double-blind method was used to compare anesthesia duration following intraligamental administration of 1.5% etidocaine with 1:200,000 epinephrine and 2% lidocaine with 1:100,000 epinephrine. Durations of anesthesia in pulpal and soft tissues were monitored following periodontal ligament injections adjacent to the maxillary canines of 20 individuals. Complete pulpal anesthesia was attained in 35% of the teeth injected with etidocaine and in 55% of those receiving lidocaine. Soft tissue anesthesia was consistently achieved. Both pulpal and soft tissue anesthesia were of longer duration following the use of lidocaine solution. These findings suggest that anesthetic duration following periodontal ligament injections is more related to the concentration of vasoconstrictor than to the anesthetic solution employed.
A case is reported of unexpected atrial fibrillation in response to tooth extraction under intravenous sedation in a 70-yr-old patient with thoracic aneurysm of the aorta. Atrial fibrillation developed after the additional injection of a 2% solution of lidocaine containing 1:200,000 epinephrine. After 20 min, the arrhythmia disappeared spontaneously. The arrhythmia was associated with insufficient analgesia for tooth extraction, epinephrine in the local anesthetic, decreased blood pressure, and the presence of cardiovascular disease. Even when a low concentration of epinephrine is employed, caution should be paid to development of unexpected cardiovascular reactions in elderly patients with severe cardiovascular disease. We conclude that an electrocardiogram, blood pressure device, and pulse oximeter should be used in high-risk patients in order to prevent and detect potentially dangerous cardiovascular emergencies, even if dental treatment is scheduled under local anesthesia.
Phentolamine mesylate accelerates recovery from oral soft tissue anesthesia in patients who have received local anesthetic injections containing a vasoconstrictor. The proposed mechanism is that phentolamine, an alpha-adrenergic antagonist, blocks the vasoconstriction associated with the epinephrine used in dental anesthetic formulations, thus enhancing the systemic absorption of the local anesthetic from the injection site. Assessments of the pharmacokinetics of lidocaine and phentolamine, and the impact of phentolamine on the pharmacokinetics of lidocaine with epinephrine were performed to characterize this potentially valuable strategy. The blood levels of phentolamine were determined following its administration intraorally and intravenously. Additionally, the effects of phentolamine mesylate on the pharmacokinetics of intraoral injections of lidocaine with epinephrine were evaluated. Sixteen subjects were enrolled in this phase 1 trial, each receiving 4 drug treatments: 1 cartridge lidocaine/epinephrine followed after 30 minutes by 1 cartridge phentolamine (1L1P), 1 cartridge phentolamine administered intravenously (1Piv), 4 cartridges lidocaine/epinephrine followed after 30 minutes by 2 cartridges phentolamine (4L2P), and 4 cartridges lidocaine/epinephrine followed by no phentolamine (4L). Pharmacokinetic parameters estimated for phentolamine, lidocaine, and epinephrine included peak plasma concentration (Cmax), time to peak plasma concentration (Tmax), area under the plasma concentration-time curve from 0 to the last time point (AUClast) or from time 0 to infinity (AUCinf), elimination half-life (t1/2), clearance (CL), and volume of distribution (Vd). The phentolamine Tmax occurred earlier following the intravenous administration of 1Piv (7 minutes than following its submucosal administration in treatment 1L1P (15 minutes) or 4L2P (11 minutes). The phentolamine t1/2, CL, and Vd values were similar for 1L1P, 1Piv, and 4L2P. The Tmax for lidocaine occurred later and the Cmax for lidocaine was slightly higher when comparing the 4L2P treatment and the 4L treatment. The phentolamine-induced delay of the lidocaine Tmax likely represents phentolamine's ability to accelerate the systemic absorption of lidocaine from oral tissues into the systemic circulation.
Pharmacokinetics; Dental local anesthesia; Lidocaine; Phentolamine; Epinephrine
The purpose of this study was to investigate the effectiveness of a combination of bupivacaine and lidocaine and that of lidocaine alone for local dental anesthesia. First, on different days, healthy volunteers were given 2% lidocaine with 1/80,000 epinephrine or 2% lidocaine with 1/80,000 epinephrine + 0.5% bupivacaine, after which pain was produced with a pulp tester. No difference was found in the time until onset of anesthetic effect between the preparations. However, the duration of anesthetic effect was longer with both lidocaine and bupivacaine than with lidocaine alone. Next, patients undergoing dental surgery were given one of the anesthetic preparations, after which serum concentrations of the anesthetics and epinephrine were measured. The maximal serum concentration of lidocaine was higher and was reached sooner after injection in patients receiving lidocaine alone (1.74 microgram/ml after 5 min) than in patients receiving both anesthetics (0.85 microgram/ml after 3 min). The mean maximal serum concentration of lidocaine was higher in patients receiving lidocaine alone (1.77 +/- 0.03 microgram/ml) than in those receiving both anesthetics (0.99 +/- 0.45 microgram/ml). Furthermore, the mean plasma concentration of epinephrine 1 min after injection was significantly higher in patients receiving lidocaine alone (0.671 ng/ml) than in patients receiving both lidocaine and bupivacaine (0.323 ng/ml). The results of this study suggest that the combination of lidocaine with epinephrine and bupivacaine produces lower systemic levels of the anesthetic and epinephrine and a longer duration of activity than lidocaine with epinephrine alone for local dental anesthesia.
The Lipospheres Bupivacaine Delivery System (bupivacaine-lipospheres) is a novel sustained-release local anesthetic preparation that has recently been made available for research purposes. This investigation compared the local anesthetic efficacy and safety of 2% bupivacaine-lipospheres, 0.5% bupivacaine plus 1:200,000 epinephrine, lipospheres plain, and physiologic saline following subcutaneous tail injection in the rat. A modified tail-flick paradigm was used to assess local anesthetic efficacy. Animals treated with 2% bupivacaine-lipospheres or 0.5% bupivacaine with epinephrine displayed significant antinociception (P < 0.05) compared to saline or lipospheres plain with 5 min of injection. Bupivacaine with epinephrine had an anesthetic duration of 30 min, whereas 2% bupivacaine-lipospheres had a duration of 3 hr. The local anesthetic blockade produced by both active solutions was completely reversible. All animals gained weight normally during the 1-wk course of the study, and there were no signs of local tissue toxicity at the injection sites. We conclude that 2% bupivacaine-lipospheres is a safe and efficacious local anesthetic preparation in this particular animal model. It possesses an onset of action that is a rapid as 0.5% bupivacaine with 1:200,000 epinephrine, and a duration that is six times longer.
In paediatric dentistry, epinephrine may contribute to systemic and local side-effects. On the other hand it is necessary to provide good and safe local analgesia. Therefore, an articaine solution with reduced epinephrine concentration was tested in a clinical setting.
In a non-interventional clinical study, dental treatment was performed in children and adolescents (4–17 years). For local analgesia, articaine 4 % plus epinephrine 1:400,000 was used in the technique chosen by the dentist. Efficacy and tolerance as well as duration of soft tissue analgesia and side-effects were evaluated.
999 patients (50.5 % male, 49.5 % female) with a mean age of 7.9 (SD 2.34) years were treated. Two hundred seventy six patients (27.6 %) received sedation prior to treatment. The mean treatment time was 15 min (SD 10). In 93.5 % of cases, initial local analgesia was sufficient to perform the planned treatment. In 99 % of cases (n = 989) the planned treatment could be completed. A second injection was necessary in 6.5 % of cases. A mean duration of soft tissue analgesia of 2.19 h (SD 1.01) was seen. Slight side-effects occurred in 3.1 % of subjects.
Due to high efficacy, tolerance and safety, the articaine 4 % solution with the reduced epinephrine concentration (1:400,000) was a safe and suitable drug for paediatric routine treatment.
Paediatric; Dental; Local analgesia; Multicentre; Articaine; Epinephrine
Addition of a vasoconstrictor to a local anesthetic may have several beneficial effects: a decrease in the peak plasma concentration of the local anesthetic agent, increase in the duration and the quality of anesthesia, reduction of the minimum concentration of anesthetic needed for nerve block, and decrease of blood loss during surgical procedures. The addition of a vasoconstrictor to a local anesthetic may also have detrimental effects. A review of the literature indicates that vasoconstrictor concentrations in local anesthetics marketed for dental use in the United States are not always optimal to achieve the purposes for which they are added. In most cases, a reduced concentration of vasoconstrictor could achieve the same goal as the marketed higher concentration, with less side-effect liability.
The efficacy of long-acting local anesthetics for anesthesia during periodontal surgery and for analgesia during the immediate postoperative period was evaluated. The rationale for using long-acting local anesthetics such as etidocaine and bupivacaine is that they can provide surgical anesthesia and, because of their long duration, prevent discomfort that may occur for 4-6 hours postoperatively. Two clinical trials were performed. The first enrolled patients requiring bilateral periodontal surgery. Using a matched pair design and double-blind randomized study conditions, 2% lidocaine 1/100,000 epinephrine was compared with 1.5% etidocaine 1/200,000 epinephrine for periodontal surgery. The time until complete recovery and the time until pain onset were found to be longer for the etidocaine surgeries. Postoperative pain appeared more severe, and the need for oral analgesics was greater for the lidocaine surgeries. Surgeons' rating of surgical bleeding was significantly greater for the etidocaine procedures. When matched bilateral surgeries were not available, a second double-blind randomized parallel trial was performed that compared 1.5% etidocaine 1/200,000 epinephrine to 0.5% bupivacaine 1/200,000 epinephrine. No significant differences were seen in the quality of anesthesia, degree of bleeding, or postoperative pain between these two long-acting anesthetics.
This study was undertaken to compare the anesthetic properties of articaine hydrochloride with 1:200,000 epinephrine (Ultracain DS) and lidocaine with 1:80,000 epinephrine (Xylocain-Adrenalin) for maxillary infiltration anesthesia. Twenty healthy dental student volunteers were included in this double-blind study. Each subject received 0.6 mL of each test solution at different times. Infiltration anesthesia was performed on the upper lateral incisor. The onset and duration of anesthesia were monitored using an electric pulp tester. No statistically significant differences were seen in the onset and duration of anesthesia between the articaine and lidocaine solutions.
The purpose of the present study was to determine how propranolol modifies the circulatory effects of epinephrine infused to produce plasma concentrations achieved during dental local anesthesia and to evaluate the effects of propranolol on the plasma clearance of epinephrine. The study was performed on six healthy male volunteers ranging in age from 25 to 34 yr. Five measurement series were performed on each of these subjects at the following times: pretreatment control, 15 min after the beginning of the first epinephrine infusion (10 ng/kg/min), 15 min after the cessation of the first epinephrine infusion, 3 min after the intravenous injection of propranolol 40 micrograms/kg, and 15 min after the beginning of the second epinephrine infusion. Plasma epinephrine clearance decreased to 54.7 +/- 9.3% of the control value after propranolol was given. Epinephrine showed initially a predominantly beta-adrenergic action, but this action was inhibited by propranolol. A relative alpha-dominant state may then occur, even when a routine volume of dental local anesthetic is administered to a chronic user of a nonselective beta blocker, and it is postulated that myocardial ischemia may develop in such patients.
We studied the effects of epinephrine or levonordefrin on the toxicity (convulsions) and lethality of four local anesthetics in mice. Appropriate doses of procaine, lidocaine, tetracaine or bupivacaine--either alone or in combination with 15 mcg/kg epinephrine or levonordefrin--were injected intravenously into the tail vein of male mice. Dose-response curves were constructed from the data obtained, and the CD50 and LD50 values for each local anesthetic alone and in combination with each of the vasoconstrictors were calculated by probit analysis. Both epinephrine and levonordefrin decreased the toxicity and lethality of procaine with respect to dose. Epinephrine, but not levonordefrin, increased the toxicity and lethality of bupivacaine as well as the lethality of tetracaine. Neither vasoconstrictor significantly affected the toxicity of lidocaine in mice but in rats epinephrine markedly increased lidocaine's lethality under identical conditions. Tight physical restraint decreased the LD50 values of all four local anesthetics and eliminated any modifying effect of the vasoconstrictor.
The effects of administering an epinephrine-containing local anesthetic on plasma catecholamine levels and cardiovascular parameters were evaluated. Significant elevations were observed following administration of 8 dental cartridges of 2% lidocaine with epinephrine 1:100,000 (144 μg) throughout the 20 minute observation period, while minimal changes were observed in the patients who received 6 cartridges of 3% mepivicaine. One minute after injection, the mean plasma epinephrine level in the group receiving epinephrine was 27.5 times higher than baseline. Concurrent elevations in systolic pressure (15%), heart rate (33%), and the rate-pressure product (52%) were also observed. These results indicate that significant amounts of epinephrine can be systemically absorbed following intraoral injection and the absorbed epinephrine can alter the cardiovascular status of the patient.
This comparative study using 20 healthy volunteers evaluated the anesthetic efficacy of 4% articaine in association with 2 different concentrations of epinephrine, 1:200,000 (G1) and 1:100,000 (G2). The first premolars were tested with a pulp tester to verify the anesthesia induced by the inferior alveolar nerve block. The following parameters were measured: period of latency (PL; interval between the end of anesthetic injection and absence of response to the maximum output--80 reading--of the pulp tester); complete pulpal anesthesia (CPA; period in which the subject had no response to maximal output of the pulp tester 80 reading); partial anesthesia (PA; interval between the first reading below 80 and the return to basal levels); and the anesthesia of the soft tissues (AST; period of time from onset of anesthesia until the return to normal sensation of the lip). The Wilcoxon test (alpha = 0.05) was used to analyze the data. No significant difference was found regarding PL (P = .47), CPA (P = .88), PA (P = .46), and AST (P = .85). The results indicated that both solutions presented the same clinical effectiveness in blocking the inferior alveolar nerve.
Anesthetic potency of a local anesthetic on the dental pulp was investigated by increasing or decreasing the concentration of lidocaine and that of epinephrine. An electromyogram of the digastric muscle in Japan White male rabbits was recorded during the jaw-opening reflex induced by electrical stimulation of the dental pulp. Probit analysis was used for the determination of the 50% effective volume (ED50) values of the anesthetic. The anesthetics used were plain 2% lidocaine solution (2Lid-0 group), 2% lidocaine solution with 12.5 microgram/mL of epinephrine (2Lid-1/8 group), 2% lidocaine solution with 6.25 microgram/mL of epinephrine (2Lid-1/16 group), and 4% lidocaine solution with 5 microgram/mL of epinephrine (4Lid-1/20 group). No anesthetic effect was shown in the 2Lid-0 group. The 2Lid-1/8 group indicated adequate anesthetic potency with the smallest dosage at all observation periods. The potency in the 2Lid-1/16 group was 0.3-0.5 times, and that in the 4Lid-1/20 group was 0.3-0.4 times as much as the 2Lid-1/8 group. The decrease in epinephrine concentration produced the decrease in the anesthetic potency on the dental pulp independent of lidocaine concentration. These results suggest that the increase in lidocaine concentration may not compensate the decrease in epinephrine concentration.
The purpose of this study was to determine the reason for an apparent increase in the number of mucosal swellings after maxillary infiltration with Citanest Forte (prilocaine HCl 4% solution with epinephrine 1:200,000), 2 years after its introduction in 1971 by Astra Pharmaceutical Co (now AstraZeneca) in the United States. Approximately 70% of these reported reactions were from California, where less than 11% of all cartridges were sold. Comparison with New York State, with 27% of total sales but less than 1% of the reactions, suggested that possible differences in practice characteristics were responsible for the swellings. On the basis of the Bureau of Economic Research and Statistics Survey of Dental Practice, dentists in the Far West (eg, California) were found to schedule appointments with a median length of approximately twice that of their Mid-East colleagues, the implication being that more anesthetic solution was injected per office visit. Follow-up telephone interviews of dentists reporting such reactions at that time verified that they administered more than the recommended 1.8-mL dose. The most important epidemiologic information was that prilocaine HCl 4% solution with epinephrine 1:200,000 had been on sale in Canada 4 years before it was introduced in the US market, with little or no evidence of drug-related effects. Comparison of the US and Canadian prilocaine HCl with epinephrine 1:200,000 specifications revealed that NaCl was added to an already hypertonic prilocaine solution in the US but not in Canada. Comparison of the responses to intradermal injection of US and Canadian prilocaine solutions into the backs of rabbits with follow-up studies of dose-related NaCl injections demonstrated that the added NaCl was responsible for the onset and duration of irritation from the initially marketed US Citanest solutions.
In a double-blind study conducted in 112 patients undergoing removal of four impacted third molar teeth, etidocaine hydrochloride 1.5% solution with epinephrine 1:200,000 and lidocaine hydrochloride 2.0% solution with epinephrine 1:100,000 were used, one on each side of the face, to produce inferior alveolar nerve block, infiltration anesthesia of the maxillary tooth and hemostasis of the mucoperiosteum around each tooth.
Surgically adequate anesthesia was rapidly produced by both agents but the duration of action of etidocaine was longer than that of lidocaine as reflected in more prolonged numbness of the lip and delayed onset of pain. Moreover, after etidocaine treatment fewer patients reported severe pain as the local anesthesia receded. No adverse local or systemic effects were observed in, or reported by, any of the patients.
The effects of epinephrine-free and epinephrine-containing local anesthetic solutions on plasma potassium and blood glucose concentrations were investigated in 20 patients undergoing oral surgery with intravenous midazolam sedation. Ten patients were randomly assigned to receive 4.4 mL of 2% lidocaine with 1:80,000 epinephrine as a local anesthetic and 10 were given 4.4 mL of 3% prilocaine with 0.03 IU/mL felypressin. There were significant changes from baseline potassium and glucose concentrations both within and between treatments in the early postinjection period. The epinephrine-containing local anesthetic significantly reduced the plasma potassium concentration 10 min after injection, by 0.16 +/- 0.20 mmol/L (mean +/- SD), and increased the blood glucose concentration at 10, 20, and 30 min (by 0.46 +/- 0.37, 0.63 +/- 0.45, and 0.56 +/- 0.28 mmol/L, respectively). Conversely, plasma potassium increased and blood glucose decreased 10, 20, and 30 min following the administration of the epinephrine-free solution. At 30 min potassium was increased by 0.24 +/- 0.16 mmol/L, and glucose was decreased by 0.23 +/- 0.16 mmol/L. It is concluded that epinephrine-free and epinephrine-containing local anesthetics differ in their metabolic effects during oral surgery with midazolam sedation.
This study was undertaken to investigate whether plain lidocaine, 3% plain mepivacaine and 3% prilocaine with felypressin were suitable epinephrine-free local anesthetic solutions for use in periodontal ligament anesthesia as alternatives to lidocaine with 1:80,000 epinephrine. Two hundred and seven patients received one of the four test solutions via a periodontal ligament injection and the success rate of anesthesia was confirmed using an electric pulp stimulator. Although neither mepivacaine nor prilocaine were as effective as lidocaine with epinephrine, the success rates of these three solutions were not statistically different. A single periodontal ligament injection of any of the solutions tested resulted in a low incidence of anesthesia. The success rate of lidocaine without epinephrine was consistently poor.
An increasing number of dental patients are taking beta-adrenergic blockers for the treatment of hypertension or angina pectoris. If epinephrine-containing local anesthetics are administered to such patients, interactions between epinephrine and the beta-blocking agent may induce cardiovascular complications. We assessed in volunteers the effects of intraoral injection with 2% lidocaine containing 1:80,000 epinephrine (L-E) on cardiac function after pretreatment with the beta-blocking agent pindolol. M-Mode echocardiography was used for the assessment. The injection of L-E after administration of pindolol did not alter cardiac preload, whereas it reduced the stroke volume, due to an increase in afterload and a decrease in myocardial contractility. Reductions in stroke volume and heart rate led to a decrease in cardiac output. Because total peripheral vascular resistance increased markedly, blood pressure was elevated despite the reduced cardiac output. These results suggest that cardiac function of dental patients on beta-blocker therapy can be adversely affected by epinephrine-containing local anesthetics. Therefore, when such an anesthetic solution has to be used in patients on beta-blocker therapy, careful systemic monitoring is needed.
The purpose of this prospective, randomized, double-blind crossover study was to evaluate the anesthetic efficacy of 2% lidocaine with 1 : 100,000 epinephrine, 4% prilocaine with 1 : 200,000 epinephrine, and 4% prilocaine in maxillary lateral incisors and first molars. Sixty subjects randomly received, in a double-blind manner, maxillary lateral incisor and first molar infiltrations of 1.8 mL of 2% lidocaine with 1 : 100,000 epinephrine, 1.8 mL of 4% prilocaine with 1 : 200,000 epinephrine, and 1.8 mL of 4% prilocaine, at 3 separate appointments spaced at least 1 week apart. The teeth were pulp-tested in 3-minute cycles for a total of 60 minutes. Anesthetic success (ie, obtaining 2 consecutive 80 readings with the electric pulp tester) and onset of pulpal anesthesia were not significantly different between 2% lidocaine with 1 : 100,000 epinephrine, 4% prilocaine with 1 : 200,000 epinephrine, and 4% prilocaine for the lateral incisor and first molar. For both lateral incisor and first molar, 4% prilocaine with 1 : 200,000 epinephrine and 2% lidocaine with 1 : 100,000 epinephrine were equivalent for incidence of pulpal anesthesia. However, neither anesthetic agent provided an hour of pulpal anesthesia. For both lateral incisor and first molar, 4% prilocaine provided a significantly shorter duration of pulpal anesthesia compared with 2% lidocaine with 1 : 100,000 epinephrine and 4% prilocaine with 1 : 200,000 epinephrine.
Lidocaine; Epinephrine; Prilocaine; Infiltration; Maxillary
Epinephrine is one of the most widely-used vasoconstrictors in dental treatment including endodontic microsurgery. However, the systemic safety of epinephrine has been in debate for many years because of its potential risk to cause cardiovascular complications. The purpose of this review was to assess the cardiovascular effect of epinephrine use in endodontic microsurgery. Endodontic microsurgery directly applies epinephrine into the bone cavity, and the amount is reported to be much larger than other dental surgeries. Moreover, when considering that systemic potency of intraosseous application is reported to be comparable to intravenous application, the systemic influence of epinephrine could be increased in endodontic microsurgery. Besides, pre-existing cardiovascular complications or drug interactions can enhance its systemic influence, resulting in increased susceptibility to cardiovascular complications. Although clinical studies have not reported significant complications for patients without severe systemic complications, many epinephrine-induced emergency cases are warning the cardiovascular risk related with pre-existing systemic disease or drug interactions. Epinephrine is a dose-sensitive drug, and its hypersensitivity reaction can be fatal to patients when it is related to cardiovascular complications. Therefore, clinicians should recognize the risk, and the usage of pre-operative patient evaluation, dose control and patient monitoring are required to ensure patient's safety during endodontic microsurgery.
Cardiovascular diseases; Drug interactions; Endodontic microsurgery; Epinephrine; Hemostasis; Vasoconstrictor agents
We report 2 cases of hypersensitivity to an epinephrine preparation in local anesthetics which were found by skin tests for local anesthetics. Both patients had uncomfortable episodes to local anesthetics at dental treatment. In both cases, the skin tests showed positive reactions to 2% lidocaine with 1:80,000 epinephrine. Furthermore drug lymphocyte stimulation test revealed positive reaction to epinephrine hydrochloride, epinephrine bitartrate in case 1, whereas in case 2, the drug lymphocyte stimulation test showed positive response to epinephrine bitartrate. Attention should be paid to exogenous epinephrine preparations that have the potential to induce hypersensitivity during dental treatment.
The purpose of this study was to measure the degree of anesthesia obtained with 4% prilocaine with 1:200,000 epinephrine and 2% mepivacaine with 1:20,000 levonordefrin compared with 2% lidocaine with 1:100,000 epinephrine for inferior alveolar nerve block. Using a repeated measures design, 30 subjects randomly received an inferior alveolar injection using masked cartridges of each solution at three successive appointments. The first molar, first premolar, lateral incisor, and contralateral canine (control) were blindly tested with an Analytic Technology pulp tester at 3-min cycles for 50 min. Anesthetic success was defined as no subject response to the maximum output of the pulp tester (80 reading) within 16 min and maintenance of this reading for the remainder of the testing period.
Although subjects felt numb subjectively, anesthetic success as defined here occurred in 46% to 57% of the molars, in 50% to 57% of the premolars, and in 21% to 36% of the lateral incisors. No statistically significant differences in onset, success, failure, or incidence were found among the solutions. We conclude that the three preparations are equivalent for inferior alveolar nerve block of 50-min duration.
Epinephrine promotes platelet aggregation through alpha 2 receptor-mediated mechanisms. In this study, the change in the platelet retention rate (PRR) was investigated before and after submucosal epinephrine injection with or without lidocaine in oral surgical patients during isoflurane-nitrous oxide anesthesia. Thirty-nine consenting patients participated in this study. Subjects were allocated in one of five groups depending on the solution injected, the diclofenac supplement, and the patients' age. PRR was measured immediately before and 5 min after epinephrine injection using a modified form of Saltzman's method. Injection of epinephrine with lidocaine deteriorated PRR, although epinephrine without lidocaine produced no PRR change. Epinephrine at doses used in routine dental practices may activate the platelet aggregating function. Dentists should keep in mind that epinephrine elicits both hemodynamic and platelet-activating effects. The latter may be of clinical importance in some situations.
Postanesthetic pain is a relatively common complication after local anesthesia. This complication may be caused by the anesthetic technique or by the anesthetic solution used. Tissue reactions induced by the anesthetic solutions may be one of the factors resulting in pain after anesthesia. The objective of this study was to comparatively analyze tissue reactions induced by different anesthetic solutions in the subcutaneous tissue of rats. The following solutions were utilized: 2% lidocaine without vasoconstrictor; a 0.5% bupivacaine solution with 1:200,000 adrenaline; a 4% articaine solution and 2% mepivacaine, both with 1:100,000 adrenaline; and a 0.9% sodium chloride solution as a control. Sterilized absorbent paper cones packed inside polyethylene tubes were soaked in the solutions and implanted in the subcutaneous region. The sacrifice periods were 1, 2, 5, and 10 days after surgery. The specimens were prepared and stained with hematoxylin and eosin for histological analysis. The results showed that there is a difference in tissue irritability produced by the local anesthetic solutions. The results also showed that there is no relation between the concentration of the drug and the inflammatory intensity, that the mepivacaine and articaine solutions promoted less inflammatory reaction than the bupivacaine, and that the lidocaine solution produced the least intense inflammation.