Anesthetic Efficacy of an Infiltration: MATERIALS AND METHODS

In: Anesthesia

26 Nov 2009


Forty adult patients participated in this study. The patients were in good health and were not taking any medications that would alter pain perception. The Ohio State University Human Subjects Review Committee approved the study, and written informed consent was obtained from each patient.

An equal number of mandibular right and left sides were tested, with the central and lateral incisors and canines chosen as the test teeth. The contralateral mandibular canine was used as the unanesthetized control to ensure that the pulp tester was operating properly and that the patient was responding appropriately during the experiment. Clinical examinations indicated that all teeth were free of caries, large restorations, and periodontal disease and that none had a history of trauma or sensitivity.
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Three appointments at least 1 week apart were scheduled for each of the 40 patients. Through use of a repeated-measures design, each patient randomly received 3 combinations of injections: an IAN block followed by a mock labial infiltration and mock lingual infiltration, an IAN block followed by a mock lingual infiltration and a labial infiltration, and an IAN block followed by a mock labial infiltration and a lingual infiltration. Before the experiment, the 3 IAN block-infiltration techniques were randomly assigned 4-digit numbers from a random number table. Each patient was randomly assigned to 1 of the 3 IAN block-infiltration techniques to determine the sequence of the injections. Only the random numbers were recorded on the data collection sheets to blind the experiment. The senior author gave all injections.

At the beginning of each appointment and before any injections were given, the experimental teeth and control canine were tested 3 times with the pulp tester (Analytic Technology Corp, Redmond, Wash) to record baseline vitality. After isolation with cotton rolls and drying with gauze, toothpaste was applied to the probe tip, which was placed midway between the gingival margin and the incisal edge of the tooth to be tested. The current rate was set at 25 seconds to increase from no output (0) to the maximum output (80). The number at initial sensation was recorded. Trained personnel, who were blinded to the IAN block-infiltration techniques administered, performed all preinjection and postinjection tests. levitra plus

A conventional IAN block was administered with a 27-gauge, l^-in needle attached to a 5-mL Luer-Lok syringe (Becton, Dickinson, and Co, Rutherford, NJ). Standard anesthetic cartridges of 2% lidocaine with 1: 100,000 epinephrine (Xylocaine with epinephrine; Astra Pharmaceutical Products, Inc, Westborough, Mass) were loaded into the 5-mL syringe and the volume was adjusted to 3.6 mL. After reaching the target area and performing aspiration, 3.6 mL of 2% lidocaine with 1: 100,000 epinephrine was deposited for 2 minutes. The IAN block was always administered before the infiltrations.

A labial or lingual infiltration, using 1.8 mL of 2% lidocaine with 1:100,000 epinephrine, was administered with a 27-gauge, 1^-in needle attached to a standard aspirating syringe (Astra Pharmaceutical Products). A standard cartridge of 1.8 mL of 2% lidocaine with 1: 100,000 epinephrine (Xylocaine; Astra Pharmaceutical Products) was loaded into the aspirating syringe. The target site was centered over the mandibular lateral incisor apex. After reaching the target area and performing aspiration, 1.8 mL of the 2% lidocaine with 1:
100,000 epinephrine was deposited for 1 minute. For the mock infiltration, a standard aspirating syringe was loaded with a cartridge of 2% lidocaine with 1:100,000 epinephrine. The needle was bent over so it did not penetrate the anesthetic cartridge; therefore, no anesthetic solution could be expressed. The mock infiltration mimicked the actual infiltration by using a 1-minute period for the injection. The needle only penetrated the mucosa a few millimeters. The subjects were instructed to close their eyes during all injections. The pulp tester personnel were not present during the injections.
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The mock infiltration (either the mock labial or mock lingual infiltration) was administered at 4 minutes after the IAN block and was always the first injection. Because lip numbness was required before the second infiltration, we did not want the patient to confuse lip numbness from the first infiltration injection, if an anesthetic solution was used, with lip numbness from the IAN block. The second infiltration was given at 6 minutes after the IAN block.

The depth of anesthesia was monitored with the pulp tester (Analytic Technology). At 1 minute after completion of the IAN and infiltrations (8 minutes after the IAN block), the injected lateral incisor and contralateral control canine were pulp tested. At 2 minutes, the adjacent central incisor and canine were tested. This cycle of testing was repeated every 2 minutes. The patient was asked if the lip was numb during the first minute and at every 2 minutes. If profound lip numbness was not recorded within 6 minutes, the block was considered missed; the patient was then rescheduled for a later appointment. Five of 120 IAN blocks were missed. The patients tested at a later date for the IAN blocks were all anesthetized successfully. All testing was stopped at 60 minutes following the IAN-infiltration injections. Your life is worth living. Buy cialis professional online

No response from the patient to the maximum output (80 reading) of the pulp tester was used as the criterion for pulpal anesthesia. Anesthesia was considered successful when 2 consecutive 80 readings were obtained within 15 minutes and the 80 reading was sustained for the 60 minutes. Clinically, in restorative dentistry, we would want patients to be anesthetized within 15 minutes and for 1 hour. Anesthesia was considered a failure if 2 consecutive 80 readings were not obtained during the 60 minutes. Clinically, patients with anesthetic failure never achieve pulpal anesthesia. Patients who developed anesthesia for less than 60 minutes were not classified as meeting criteria for success or failure.

Data were analyzed statistically. Comparisons between the injection combinations were made using multiple McNemar tests for anesthetic success and failure. All P values were Bonferroni adjusted using the step-down method of Holm. Comparisons were considered significant at P < .05.

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