Evaluation of lidocaine in human inferior alveolar nerve block

0099-2399/97/2309-0575503.00/0 JOURNALOF ENDODONTICS Copyright © 1997 by The American Association of Endodontists

Printed in U.S.A.

VOL. 23, No. 9, SEPTEMBER1997

Evaluation of Lidocaine in Human Inferior Alveolar Nerve Block Ghassan M. Yared, DCD, DSO, and Fadia Bou Dagher, DCD, DSO

The purpose of this study was to measure the degree of anesthesia following the administration of 3.6 ml of 2 % lidocaine solutions with either 1:50,000, 1:80,000, or 1:100,000 for inferior alveolar nerve block and to compare the results with those obtained following the administration of 1.8 ml of the same solutions (1). With the use of a repeated measures design, 30 subjects randomly received an inferior alveolar injection 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 rain. The degree of anesthesia was comparable for the three solutions following the administration of 3.6 ml of each solution. Retrospective evaluation showed that the volume of the solution influenced the degree of anesthesia.

The 30 adult subjects, 22 men and 8 women, ranging in age from 22 to 50 yr, with an average of 32 yr, who had participated in a previous recent study, were included in this study. The subjects were in good health and were not taking any medications that would alter pain perception. A written consent was obtained from each subject. An equal number of mandibular right and left sides were tested with the first molar, first premolar, and lateral incisor chosen as the test teeth. The contralateral canine was used as the unanesthetized control to ensure that the pulp tester was operating properly and the subject would respond 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. Using a repeated measures design, each subject randomly received each anesthetic solution on three successive appointments at least 1 week apart. The anesthetic solutions tested were: 3.6 ml of 2% lidocaine with 1:50,000 epinephrine (Octocaine, Novocol Pharmaceutical, Canada); 3.6 ml of 2% lidocaine with 1:80,000 epinephrine (Xylorolland, Produits Dentaires, Pierre Rolland, France); and 3.6 ml of 2% lidocaine with 1:100,000 epinephrine (Xylocaine with Epinephrine, Astra, Pharmaceutical Products, Inc., Westborough, MA). These solutions were designated by D, E, and F respectively. The sequence of solution administration was determined randomly, and all the injections were given blindly by one operator. For each injection, a 5-ml syringe was used to administrate 3.6 ml of each solution, i.e. the equivalent of two 1.8-ml cartridges of the anesthetic solution. At each appointment and before injection, the experimental teeth and control canine were tested three times with the pulp tester (Analytic Technology Corp., Redmond, WA) to record baseline vitality. Following 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 occlussal edge. The current rate was set at 25 s to increase from no output (0) to the maximum output (80). The number at initial sensation was recorded. Soft tissue responsiveness labial and lingual to the premolar and buccal to the first molar was tested by sticking the alveolar mucosa with a sharp explorer. All preinjection and postinjection tests were done by a trained person who was blinded to the solutions injected. A standard inferior alveolar injection, as described by Malamed (9), was administered with a 30-gauge long needle and an aspirating syringe by the same operator of the study of Bou Dagher et al. (1). The solution was deposited at a rate of 80 s/ml. Aspiration was

Routine local anesthetic techniques such as the inferior alveolar nerve block often fail to provide complete anesthesia. The influence on the degree of anesthesia of different parameters such as the volume and concenwation of the injected anesthetic solution and its epinephrine dose have been evaluated (1-8). Vreeland et al. (2) found no significant differences in success or failure when lidocaine with epinephrine was doubled in volume (from 1.8 ml to 3.6 ml). Recently, Bou Dagher et al. (1) measured the degree of anesthesia following the administration of 1.8 ml of different solutions of 2% lidocaine and found no difference among the three solutions. The purpose of this study was to measure the degree of anesthesia following an IAN block with 3.6 ml of the same solutions used in the study of Bou Dagher et al. (l) and to compare the results with those obtained recently following the administration of 1.8 ml of the anesthetic solutions used in the study of Bou Dagher et al. (1).

M A T E R I A L S AND M E T H O D S The methodology of the present study is identical to that of McLean et al. (3) and Bou Dagher et al. (1).

575

576

Journal of Endodontics

Yared and Bou Dagher

TABLE 1. Number and percentage of subjects who experienced soft tissue anesthesia to mucosal sticks. Solution

Mental

Lingual

100%

T

Buccal 80%

D E F

28 29 28

93.30% 96.60% 93.30%

30 30 30

100% 100% 100%

29 29 28

96.60% 96.60% 93.30%

50%

TABLE 2. Number of subjects who experienced anesthetic success, anesthetic failure, slow onset of anesthesia, noncontinuous anesthesia, and anesthesia of short duration. No significant difference was found among the 3 groups.

]

70%

i

60% }

i-o-Dl

/

I--~-Ei

40% -

i

r

30% 2O% 10%

Solution

First Molar

First Premolar

Lateral Incisor

i 0%

=

i

i

i ,,

~

~ - ~

~

i

i~ i

;

~

i

i

Anesthetic Success

D E F Anesthetic failure D E F Slow onset of anesthesia D E F Noncontinuous anesthesia D E F Anesthesia of short duration D E F

23 28 23

77% 93% 77%

24 28 24

80% 93% 80%

21 27 20

70% 90% 67%

4 4 3

13% 13% 10%

2 2 1

7% 7% 3%

5 3 4

17% 10% 13%

4 2 5

13% 7% 17%

3 1 1

10% 3% 3%

2 1 3

7% 3% 10%

0 0 0

0% 0% 0%

0 0 0

0% 0% 0%

0 0 0

0% 0% 0%

5 2 3

17% 7% 10%

4 3 6

13% 10% 20%

2 1 3

7% 3% 10%

performed after needle penetration and during deposition of the anesthetic solution. At 1 rain postinjection, the first molar was pulp tested and alveolar mucosal sticks were performed. At 2 rain, the first premolar and lateral incisor were tested. At 3 rain, the control canine was tested and the subject was asked if the lip and tongue were numb. This cycle of testing was repeated every 3 rain. All testing was stopped at 50 min postinjection. Lip and tongue anesthesia were considered successful when the subject felt numbness within 20 rain and/or did not respond to mucosal sticks. Pulpal anesthesia was defined as no subject response to the pulp tester at an 80 reading. Experimentally, the 80 reading is an end point that can be used to measure complete pulpal anesthesia over time. Clinically, the 80 reading will provide complete pulpal anesthesia in asymptomatic vital teeth. However, readings less than 80 may provide clinical anesthesia, and this would depend on the type of procedure performed and the requirements for complete pulpal anesthesia. Therefore, the results presented in this study may not reflect clinical success or failure. The time for onset of pulpal anesthesia was recorded at the first of two consecutive 80 readings. Anesthesia was considered successful if an 80 reading was achieved within 16 rain and when this reading was sustained for the remainder of the 50-rain test period. Anesthesia was considered a failure if the subject never achieved

FIG 1. Incidence of first molar anesthesia (percentages of 80/80 readings), at each postinjection interval, for the three 3.6 ml solutions. There were no significant differences among the solutions at any time interval.

two consecutive 80 readings during the 50 min. Anesthesia was noncontinuous if the subject achieved two consecutive 80 readings, lost the 80 reading, and then regained the 80 reading during the 50 rain. Anesthesia was of slow onset if the subject achieved two consecutive 80 readings after 16 min. Anesthesia was of short duration if the subject achieved two consecutive 80 readings, lost the 80 readings, and never regained it within the 50-rain period. Anesthetic success and failure and incidence of pulpal anesthesia were analyzed nonparametrically using the chi-square test (c~ = 0.05). The results were compared to those obtained in a recent study following the administration of 1.8 ml of the same solutions (1).

RESULTS The 30 subjects had subjective lip and tongue numbness. The number and percentage of subjects who experienced soft tissue anesthesia to mucosal sticks are listed in Table 1. The mean baseline pulp test readings were as follows: first molar, 41; first premolar, 34; lateral incisor, 28; and control canine, 34. All control canines responded positively during the experiment. The number and percentage of subjects who experienced anesthetic success, anesthetic failure, slow onset of anesthesia, noncontinuous anesthesia, and anesthesia of short duration are listed in Table 2. There were no significant differences among the solutions. Figure 1 shows the incidence of first molar anesthesia at each time interval. The same results were obtained with the premolar and the incisor. The highest incidences for all three solutions were as follows: first molar, 87% to 93%; first premolar 93%; and lateral incisor, 83% to 90%. There were no significant differences among the solutions at any time interval. The number of subjects who experienced anesthetic success, anesthetic failure, slow onset of anesthesia, noncontinuous anesthesia, and anesthesia of short duration following the administration of 1.8 ml of the same solution (1) was compared to the results obtained in the present study (Table 3). The comparison was made between the following group pairs: A-D, B-E, and C-F; A, B, and C being 1.8 ml of the same solutions as D, E, and F respectively (Table 3). Figure 2 shows the incidence of first molar anesthesia (percent-

Lidocaine in Human Nerve Block

Vol. 23, No. 9, September 1997

577

TABLE 3. Number of subjects who experienced anesthetic success, anesthetic failure, slow onset of anesthesia, noncontinuous anesthesia, and anesthesia of short duration following the administration of 1.8 ml solutions (A, B, and C) (1) and of 3.6 ml solutions (D, E, and F) (present study). Solution*

First Molar

Anesthetic success A

B C D E F Anesthetic failure A

B C D E F Slow onset of anesthesia A

B C D E F Noncontinuous anesthesia A

B C D E F Anesthesia of short duration A

Lateral Incisor

15 19 14 23 28 23

50% 63% 47% 77% 87% 77%

16 20 13 24 28 24

53% 67% 43% 80% 93% 80%

4 3 3 4 4 3

13% 10% 10% 13% 13% 10%

3

10%

2 1

10% 7% 7% 3%

4

13%

8

27%

9

2

7%

5

17%

5

3 4 2 5

10% 13% 7% 17%

5 3 1 1

17% 10% 3% 3%

3

30% 17% 23% 7% 3% 10%

6 5 6 0 0 0

20% 17% 20% 0% 0% 0%

7 5 8 0 0 0

23% 17% 27% 0% 0% 0%

6 5 8 0 0 0

20% 17% 27% 0% 0% 0%

7

23% 17% 17% 17% 7% 10%

9

30% 23% 20% 13% 10% 20%

B C D E F

First Premolar

5 2 3

7

I6 4 3 6

14 17 21 15 27 20

47% 57% 50% 70% 90% 67% 23% 17% 27% 17% 10% 13%

20% 17% 17% 7% 3% 10%

*Groups joined with vertical lines did not demonstrate a statistically significant difference.

age of 80/80 readings), at each postinjection interval, for the 1.8 and 3.6 ml solutions of 2% lidocaine with 1:50,000 epinephrine. This figure is representative of the incidence of first molar, first premolar, and lateral anesthesia, at each postinjection interval, for the 1.8 and 3.6 ml volumes of the 3 anesthetic solutions. The incidence of anesthesia was greater when the solutions were doubled in volume.

100% T 90%

8O%t

DISCUSSION The reason these anesthetic solutions were evaluated in a recent (1) and in the present study was that they are the most commonly used anesthetic solutions by Lebanese dentists. All 30 subjects had profound lip numbness, and mental and lingual mucosal sticks indicating a high incidence of success (Table 1). Since pulp testing showed a lower incidence of anesthesia, lip numbness and negative mucosal responses may not indicate onset or guarantee successful pulpal anesthesia. This finding agrees with two recent studies (1, 3). The mean baseline pulp test readings were quite similar to those recorded in the study of Bou Dagher et al. (1). These results demonstrate the reliability of the Analytic Technology pulp tester in testing intact and/or minimally restored vital teeth.

o% I E FIG 2. Incidence of first molar anesthesia (percentages of 80/80 readings), at each postinjection interval, for the 1.8 and 3.6 ml solutions of 2% lidocaine with 1:50,000 epinephrine. *No significant differences between the solutions.

578

Journal of Endodontics

Yared and Bou Dagher

Anesthesia success and failure (Table 2) and incidence of anesthesia (Fig. l) were not significantly different among the three solutions. Therefore, the three solutions (3.6 ml of each) areequivalent in inferior alveolar nerve blocks of 50-min duration. This conclusion agrees with that of Bou Dagher et al. (1) after the administration of 1.8 ml of the same solutions for IAN blocks. On the other hand, the results of the present study and those of Bou Dagher et al. (1) generally indicated significant differences in success or failure when lidocaine with epinephrine was doubled in volume (from 1.8 ml to 3.6 ml) (Table 3). This finding disagrees with the results of Vreeland et al. (2), but a direct comparison cannot be made because of differences in the methodology and the materials. Anesthetic success was not significantly different for the lateral incisor between 1.8 ml and 3.6 ml solutions of lidocaine with 1:50,000 epinephrine (i.e. solutions A and D respectively) on one hand and with 1:100,000 epinephrine (i.e. solutions C and F respectively) on the other. The lateral incisor presented a higher although not significant incidence of failure than the molar and premolar (Table 2). This was also observed following the administration of 1.8 ml of anesthetic solution (Table 3) (1). Theories for inadequate anesthesia were discussed by Vreeland (2). it is noteworthy that no significant difference in anesthetic success was found between the 1.8 ml and 3.6 ml solutions before 4 and 5 min for the first molar and for the first premolar and lateral incisor respectively. The nonsignificant difference in success, at the last time period, between solutions C and F for the molar, A and D for the premolar, B and E for the lateral incisor, and C and F for the lateral incisor, might be explained by a short duration anesthesia or by a noncontinuous anesthesia. The results concerning slow onset, noncontinuous, and short duration anesthesia were comparable for the three 3.6 ml solution groups, i.e. groups D, E, and F. Onset and duration of anesthesia following the injection of 3.6 ml solution were not significantly different from those obtained after the administration of 1.8 ml solution (1) for each solution with one exception (Table 3): slow onset of anesthesia occurred less frequently with the lateral incisor when 2% lidocaine with 1:50,000 epinephrine was doubled in volume (solution A and D). Interestingly, anesthesia was continuous for the three groups in contrast to anesthesia obtained following the administration of a 1.8-ml solution (1) (Table 3). Noncontinuous anesthesia may indicate a change in ionized and nonionized forms of the anesthetic resulting in inadequate anesthesia at some time periods (3).

Examination of Table 3 reveals that in general with 1.8 ml and 3.6 ml solutions of 2% lidocaine with 1:80,000 epinephrine more subjects experienced anesthetic success and less subjects experienced anesthetic failure, slow onset, and short duration than with 1.8 ml and 3.6 ml solutions of 2% lidocaine with 1:50,000 and 1:100,000 epinephrine. Although, this difference is somewhat evident, it is not statistically significant. The present study is in agreement with Bou Dagher et al. (1) who demonstrated that the epinephrine concentration in a 2% lidocaine hydrochloride did not influence the degree of anesthesia since the three solutions D, E, and F are comparable in inferior alveolar nerve blocks. It is noteworthy that the same operator administered the anesthetic solution in the 1.8-ml solution study and the present study to eliminate variability due to a difference in the injection technique. Dr. Yared is assistant professor, chairman, Department of Research, chairman, Postgraduate Program of Endodontics, and member, Department of Endodontics, Dental School, Lebanese University, Beirut, Lebanon.Dr. Bou Dagher is assistant professor, chairman, Department of Oral Fundamental Sciences, chairman, Postgraduate Program of Oral fundamental Sciences, and member, Department of Endodontics, Dental School, Lebanese University, Beirut, Lebanon. Address requests for reprints to Ghassan M. Yared, c/o Dr. Ajaj Jarrouj, 35 Howe Avenue, Wayne, NJ 07470-3937.

References 1. Malamed SF. Techniques of mandibular anesthesia. In: Handbook of local anesthesia. St Louis: C.V. Mosby Company; 1980:163-73. 2. Vreeland DL, Reader A, Beck M, Meyers W, Weaver J. An evaluation of volumes and concentrations of lidocaine in human inferior alveolar nerve block. J Endodon 1989;15:6-12. 3. Mc Lean C, Reader A, Beck M, Meyers W. An evaluation of 4% prilocaine and 3% mepivacaine compared with 2% lidocaine (1:100,000 epinephrine) for inferior alveolar nerve block. J Endodon 1993;19:146-50. 4. Keesling GR, Hinds EC. Optional concentration of epinephrine in lidocaine solutions. J Am Dent Assoc 1963;66:337-40. 5. Gangarosa LP, Halik FJ. A clinical evaluation of local anesthetic solutions containing graded epinephrine concentrations. Arch Oral Bio11967;12: 611-21. 6. Handler LE, Albers DD. The effects of the vasoconstrictor epinephrine on the duration of pulpal anesthesia using the intraligamentary injection. J Am Dent Assoe 1987;114:807-9. 7. Fink BR. Neural pharmkodynamics of epinephrine. Anesthesiology 1978;48:263- 8. 8. KnolI-Kohler E, Frrtsch G. Pulpal anesthesia dependent on epinephrine dose in 2% fidocaine.Orat Surg 1992;73:537-40. 9. Dreven LJ, Reader A, Beck FM, Meyers WJ, Weaver J. An evaluation of an electric pulp tester as a measure of analgesia in human vital teeth. J Endodon 1987;13:233-8.

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