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Anesthetic efficacy of the intraosseous injection of 2% lidocaine (1:100,000 epinephrine) and 3% mepivacaine in mandibular first molars
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Anesthetic efficacy of the intraosseous injection of 2% lidocaine (1:100,000 epinephrine) and 3 % mepivacaine in mandibular first molars K a r a n R e p l o g l e , D D S , M S , a A1 Reader, D D S , M S , b R o b e r t Nist, D D S , M S , c M i k e Beck, D D S , M A , a Joel W e a v e r , D D S , PhD, e and W i l l i a m J. M e y e r s , D M D , M E d , f C o l u m b u s , O h i o THE OHIO STATE UNIVERSITY
Objectives. This study compared the anesthetic efficacy of a primary intraosseous injection of 2% lidocaine with 1:100,000 epinephrine and 3% mepivacaine in human mandibular first molars. Injection pain and healing postoperatively were also assessed for the intraosseous injection. Study design. With the use of a repeated-measures design, 42 subjects randomly received intraosseous injections of 1.8 ml of 2% lidocaine with 1:100,000 epinephrine or 1.8 ml of 3% mepivacaine in a double-blind manner at two successive appointments. ,The fi!~t molar and adjacent teeth were blindly tested with an electric pulp tester at 2-minute cycles for 60 minutes. Anesthetic success was defined as no subject response to the maximum output of the pulp tester (80 reading) for two consecutive readings. Results. Anesthetic success occurred in 74% of the first molars with 2% ]idocaine with 1:100,000 epinephrine and in 45% with 3% mepivacaine. The difference was statistically significant (p < 0.05). Overall, onset was rapid for the intraosseous injections, the duration of pulpal anesthesia steadily declined over the 60 minutes, the majority of the subjects had no pain or mi[d pain with perforation and solution deposition, and 5% of the subjects had delayed healing at the perforation sites. Conclusions. The results of this study indicate that the primary intraosseous injection of 2% [idocaine with 1:100,000 epinephrine is more successful and results in a longer duration of pulpal anesthesia as compared with 3% mepivacaine in noninflamed mandibular first molars. Most subjects reported no or mild pain during perforation and injection. (Oral Surg Oral Med Oral Patho| Oral Radiol Fndod 1997;83:30-7)
T h e intraosseous (IO) injection a l l o w s p l a c e m e n t o f a local anesthetic solution directly into the c a n c e l l o u s b o n e a d j a c e n t to the tooth to be anesthetized. Historically, various m e t h o d s o f a c c e s s i n g the c a n c e l l o u s Study was supported by Graduate Endodontic Research Fund. aFormer Graduate Student in Endodontics. bProfessor and Program Director, Division of Endodontics. °Associate Clinical Professor, Division of Endodontics. aAssociate Professor, Department of Health Services Research. eAssociate Professor, Department of Oral and Maxillofacial Surgery. fFormer Chairman and Professor, Department of Endodontics/Diagnostic Services. Submitted for publication May 10, 1996; returned for revision JulY 16, 1996; accepted for publication Aug. 27, 1996. Copyright © 1997 by Mosby-Year Book, Inc. 1079-2104/97/$5.00 + 0 7/15/77717 30
space h a v e i n c l u d e d drilling a hole t h r o u g h the cortical b o n e using a r o u n d bur, drill, or e n d o d o n t i c reamer. 1-4 Currently, there is an IO s y s t e m m a r k e t e d under the trade n a m e S t a b i d e n t (Fairfax D e n t a l Inc., M i a m i , Fla.). This s y s t e m is c o m p r i s e d o f a slows p e e d h a n d p i e c e - d r i v e n p e r f o r a t o r (a solid 2 7 - g a u g e w i r e with a b e v e l e d end) that w h e n activated drills a small h o l e through the cortical plate. T h e anesthetic solution is d e l i v e r e d to cancellous b o n e through a 2 7 - g a u g e ultrashort injector n e e d l e p l a c e d into the hole m a d e b y the perforator. The S t a b i d e n t I O injection has been e v a l u a t e d as a p r i m a r y and s u p p l e m e n t a l injection. In a clinical study, L e o n a r d 5 r e p o r t e d a 90% success rate for extractions with this system. In an e x p e r i m e n t a l study, C o g g i n s et al. 6 u s e d the S t a b i d e n t s y s t e m as a p r i m a r y
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injection in various groups of maxillary and mandibular teeth. They reported success rates of 75% for the mandibular first molar, 93% for the maxillary first molar, 7 8 % for the mandibular lateral incisor, and 90% for the maxillary lateral incisor with 1.8 ml of 2% lidocaine with 1:100,000 epinephrine. Dunbar et al. 7 evaluated the Stabident system in mandibular first molars as a supplemental injection to the inferior alveolar nerve (IAN) block. They recorded a high incidence (98%) of pulpal anesthesia with the combination IO/IAN technique. Although the IO injection has been studied clinically and experimentally, no objective study has evaluated the IO Stabident technique as a primary injection with 3% mepivacaine. The purpose of this study was to compare the anesthetic efficacy of an IO injection of 2% lidocaine with 1:100,000 epinephrine versus 3% mepivacaine in human mandibular first molars, Injection pain and healing postoperatively were also assessed for the IO injection. MATERIAL A N D METHODS Forty-two adult subjects, 25 men and 17 women, from age 18 to 39 years with an average age of 25 years, participated. The subjects were in good health and not taking any medications that would alter pain perception. The study was approved by The Ohio State University Human Subjects Review Committee; written informed consent was obtained from each subject. Forty-four IO injections were administered to the right mandible and 40 to the left mandible. The mandibular first molar, second molar, and second premolar were chosen as the test teeth. The contralateral canine was used as the unanesthetized control to ensure that the pulp tester was operating properly and that the subject 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. Two appointments at least 2 weeks apart were scheduled for each of the 42 subjects. With a repeated-measures design, each subject randomly received either an IO injection of 1.8 ml of 2% lidocaine with 1:100,000 epinephrine or 1.8 ml of 3% mepivacaine at the two successive appointments. The solution not administered at the first appointment was given atthe second appointment. To effectively blind the operator and subject to the solutions administered, each anesthetic cartridge (lidocaine or mepivacaine) was masked with a white opaque label and numbered to determine the order of anesthetic administration. A trained assistant loaded each syringe before the appointment.
At each appointment and before injection, the first molar, mesial, and distal adjacent teeth, and control canine were tested three times with an electric 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 occlusal edge. The current rate of the pulp tester was set at 25 seconds to increase from no output (0) to the m a x i m u m output of 80. The number at initial sensation was recorded. All preinjection and postinjection tests were performed by trained personnel who were blinded to the anesthetic solutions administered. The IO injection was given with the Stabident system. With the subjects in a reclining position, the area of perforation was determined with the horizontal line of the buccal gingival margins of the first molar and adjacent teeth and a vertical line that passed through the interdental papilla on the distal aspect of the first molar. A point approximately 2 m m below the intersection of these lines was selected as the perforation site if the site was in attached gingiva. If this point was in alveolar mucosa (three subjects), the injection site was moved 1 m m above the junction of the attached gingiva and alveolar mucosa. The soft tissue at the determined perforation site was anesthetized with an infiltration of approximately 0.1 ml of either 2% lidocaine with 1:100,000 epinephrine (Astra Pharmaceutical Products, Westboro, Mass.) or 3% mepivacalne (Cook-Waite, Seattle, Wash.) deposited through a 30-gauge needle attached to a standard aspirating syringe. These cartridges were also blinded and were loaded into separate syringes. The cortical bone was then perforated with the Stabident perforator (a beveled-ended solid wire attached to a plastic hub) in a contra-angle, slow-speed handpiece. The perforator was placed through the gingiva at the infiltration site and was oriented perpendicular to the cortical plate. With the point gently resting against bone, the handpiece was activated in a series of short bursts with light pressure until a "breakthrough" feeling was observed or until 2 to 5 seconds had elapsed. Before inserting the 27-gauge ultrashort Stabident needle through the perforation, the needle was bent at the hub to a 45-degree angle to allow for ease of insertion. When bleeding obscured the perforation site, the area was blotted with a sterile cotton roll to control hemorrhage and to identify the perforation site. The standard syringe was held in a "pengripping" fashion, and the needle was inserted into the perforation site and 1.8 ml of 2% lidocaine with 1:100,000 epinephrine or 3% mepivacaine was delivered over a 2-minute time period. If back-pressure
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ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY
January 1997 Table I. Percentages and discomfort ratings of infiltration and intraosseous injections Injection Phase/Solution
Infiltration Injection* 2% Lidocaine (1:100,000) 3% Mepivacaine Intraosseous Injection* Perforation 2% Lidocaine (1:100,000) 3% Mepivacaine Needle insertion 2% Lidocaine (1:100,000) 3% Mepivacaine Solution deposition 2% Lidocaine (1:100,000) 3% Mepivacaine
None
Mild
Moderate
Severe
52% (22/42) 43% (18/42)
45% (19/42) 55% (23/42)
2% (1/42) 2% (1/42)
0% (0/42) 0% (0/42)
83% (35/42) 86% (36/42)
10% (4/42) 5% (2/42)
7% (3/42) 0% (0/40)
0% (0/42) 0% (0/42)
95% (40/42) 83% (35/40)
5% (2/42) 17% (7/42)
0% (0/42) 2% (1/42)
0% (0/42) 0% (0/42)
79% (33/42) 55% (23/42)
19% (8/42) 36% (15/42)
2% (1/42) 7% (3/42)
0% (0/42) 2% (1/42)
*There were no significant differences between the solutions (p > 0.05).
Table II. Percentages and number of subjects who experienced anesthetic success and failure Solution/Tooth
2% Lidocaine (1:100,000) Mandibular second molar Mandibular first molar* Mandibular second premolar 3% Mepivacaine Mandibular second molar Mandibular first molar* Mandibular second premolar
Success
Failure
76% (32/42) 74% (31/42) 57% (24/42)
24% (10/42) 26% (11/42) 43% (18/42)
67% (28/42) 45% (19/42)? 41% (17/42)
33% (14/42) 55% (23/42)? 59% (25/42)
*Experimental Tooth ?Statistically significant difference beween solutions (p < 0.05).
(defined as greater than light finger pressure on the syringe handle to deliver the solution) was encountered on solution deposition, the needle was rotated approximately a quarter turn and deposition was reattempted. If this was not successful, the needle was removed and checked for blockage. If not blocked, it was reinserted or the site was reperforated with a new perforator and the injection completed. The subjects were instructed to rate the pain of the infiltration and IO injections. The rating scale was: 0, no pain; 1, mild pain (pain that is recognizable but not discomforting); 2, moderate pain (pain that is discomforting but bearable); and 3, severe pain (pain that causes considerable discomfort and is difficult to bear). At 1 minute after the IO injection, the first molar and adjacent distal tooth were pulp tested. At 2 minutes, the adjacent mesial tooth and contralateral control canine were tested. This cycle of testing was repeated every 2 minutes. The control canine was tested every third cycle with an inactive pulp tester to test the reliability of the subject. All testing was stopped at 60 minutes after injection.
No subject response to the m a x i m u m output (80 reading) of the pulp tester was used as the criterion for pulpal anesthesia. Anesthesia was considered successful when two consecutive 80 readings were obtained at any time during the 60 minutes. Anesthesia was considered a failure if the subject never achieved two consecutive 80 readings during the 60 minutes. Onset and duration of subjective lip anesthesia was monitored by asking the question " I s your lip n u m b ? " at each minute for 60 minutes. A postinjection questionnaire asked the subjects to rate the pain and any side effects in the area of the IO injection at the time initial numbness wore off and in the morning for 3 days after the appointment. Between-solution differences in incidence of pulpal anesthesia (80 readings), success, and failure were analyzed nonparametrically with Bonferroni adjusted M c N e m a r tests. Differences in pain ratings for infiltration, IO injections, and postoperative scores were analyzed with Wilcoxon's matched pairs, signed rank test. Comparisons were considered significant at p < 0.05.
RESULTS The discomfort ratings for the infiltration and IO injections are presented in Table I. Generally, the infiltration and intraosseous injections resulted in none or mild pain ratings the majority o f the time. There were no significant differences between the solutions (p > 0.05). Anesthetic success and failure are presented in Table II. For the mandibular first molar, success was 74% with 2% lidocaine (1:100,000 epinephrine), and success for 3% mepivacaine was 45%. There was a statistically significant difference between the solutions (p < 0.05). The incidence of pulpal anesthesia and significant
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY
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Volume 83, Number 1
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Time (minutes) Fig. 1. Incidence of anesthesia for mandibular first molar as determined by lack of response to electric pulp testing at maximal setting (percentage of 80/80s) at each postinjection time interval. Significant differences (p < 0.05) between 2% lidocaine (1:100,000) and 3% mepivacaine are indicated by an asterisk.
differences between solutions for the mandibular first molar are presented in Fig. 1. Statistical differences were shown from 8 through 30 minutes and at 40 minutes when comparing the two solutions. Incidence of anesthesia for the adjacent teeth are presented in Figs. 2 and 3. The postinjection discomfort ratings for the IO injections are presented in Table III. Postinjection pain was rated as none to mild in 93% to 97% of the injections; pain ratings decreased over the next 3 days (Table III). There were no significant differences between the solutions (p > 0.05). There was a 5% (4 of 84) incidence of postinjection swelling or exudate at the IO injection site. Thirteen percent (11 of 84) of the subjects reported the experimental tooth felt high when chewing.
DISCUSSION The anesthetic success rate in this study (74%) was similar to the results of Coggins et al. 6 who also used 2% lidocaine with 1:100,000 epinephrine for the primary IO injection of mandibular first molars. They reported a 75% success rate. The lack of 100% success may be related to a thick or dense cortical bone preventing perforation into cancellous bone or limited anesthetic solution distribution because of a constricted cancellous space. The IO injection of 2%
lidocaine with 1:100,000 epinephrine may provide pulpal anesthesia in approximately 75% of noninflamed mandibular first molars when used as a primary technique. The anesthetic success rate (45%) with 3% mepivacaine was lower as compared with the lidocaine solution (74%) (Table II). Previous studies 8-11 on the periodontal ligament injection (a type of IO injection) have also shown lower success rates when using anesthetic solutions that do not contain vasoconstrictors or have reduced vasoconstrictor concentrations. Therefore when 3% mepivacaine is used as a primary injection intraosseously, approximately 45% of the patients will have pulpal anesthesia. As shown in Fig. 1 for the first molar, onset of anesthesia (highest percentage of initial 80 readings) occurred within the first three testing times (6 minutes) for both solutions. Therefore onset of anesthesia was rapid for the IO injection. Coggins et al. 6 also reported rapid onset of anesthesia with the IO injection. Duration of anesthesia for both solutions steadily declined over the 60 minutes (Fig. 1). At 20 minutes, 62% of the subjects had pulpal anesthesia with 2% lidocaine (1:100,000 epinephrine) and only 24% with 3% mepivacaine. At 30 minutes, 52% of the subjects had pulpal anesthesia with the lidocaine solution and
34
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY January 1997
Replogle et al.
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Fig. 2. Incidence of anesthesia for mandibular second molar as determined by lack of response to electric pulp testing at maximal setting (percentage of 80/80s) at each postinjection time interval. Significant differences (p < 0.05) between 2% lidocaine (1:100,000) and 3% mepivacaine are indicated by an asterisk.
17% with 3% mepivacaine. At 45 minutes, 29% of the subjects had pulpal anesthesia with the lidocaine solution and 7% with 3% mepivacaine. When 2% lidocaine with 1:100,000 epinephrine was compared with 3% mepivacaine, the incidence of pulpal anesthesia was statistically significant at 8 through 30 minutes as well as at 40 minutes (Fig. 1). Therefore for those patients who achieve pulpal anesthesia, 2% lidocaine (1:100,000 epinephrine) may provide anesthesia for procedures of short duration as demonstrated by Leonard. 5 Three percent mepivacaine will provide an even shorter duration of pulpal anesthesia. Considering the success rates and duration of the primary I t injections in this study, the true value of the I t injection may be its use as a supplemental injection. Dunbar et al.7 demonstrated that when the I t injection was added to the I A N block a high incidence (98%) of pulpal anesthesia was obtained; 90% of the first molars were still anesthetized at 60 minutes. Nusstein et al. az found a supplemental I t injection was 88% successful in providing profound pulpal anesthesia in posterior teeth diagnosed with irreversible pulpitis. Both of these studies used 2% lidocaine with 1:100,000 epinephrine. The efficacy of 3% mepivacaine as a supplemental injection is not known and is currently under investigation. Although the Stabident manual suggests that 0.9 ml
of solution be deposited to anesthetize three adjacent teeth, no studies have been performed to support this statement. We used 1.8 ml of both solutions to evaluate the effect this volume has on pulpal anesthesia. With this as a guideline, future studies may address reduced amounts of solution. Anesthesia of adjacent teeth is presented in Table II and Figs. 2 and 3. For the second molar, anesthetic success, failure, and the incidence of pulpal anesthesia were fairly similar between the experimental first molar and this distal adjacent tooth for the two solutions. Coggins et al. 6 reported comparable results in his study of mandibular molars. Generally, for the second molar, a mesial I t injection (distal injection to the experimental first molar) of either solution would result in a similar incidence o f pulpal anesthesia as the first molar. The success rates and incidence of pulpal anesthesia for the adjacent mesial tooth were lower than the experimental tooth (Table II and Figs. 2 and 3). Similar results were reported by Dunbar et al. 7 and Coggins et al. 6 The most likely reason for the difference between mesial and distal teeth is the selection of the distal I t injection site. To provide an equal anesthetic effect for the mesial tooth, the solution would have to spread past the experimental tooth or block the nerve trunk near to or at the site of injection. Because neither occurred readily enough to
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Volume 83, Number 1
100 • 2 ~ Lidocaine {1:100,000) • 3~ Mepivacaine I/}
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50
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Time (minutes) Fig. 3. Incidence of anesthesia for mandibular second premolar as determined by lack of response to electric pulp testing at maximal setting (percentage of 80/80s) at each postinjection time interval. There were no significant differences (p > 0.05) between 2% lidocaine (1:100,000) and 3% mepivacaine.
result in anesthesia of the mesial tooth at a level equal to the experimental tooth, an IO injection distal to the mesial tooth may result in better anesthesia of the mesial tooth. Subjective assessment of lip anesthesia after the IO injection of the mandibular first molar showed that 76% (32 of 42) of the subjects had "lip n u m b n e s s " with the lidocaine solution and 50% (21 of 42) with the mepivacaine solution. Onset of lip numbness occurred within 2 to 4 minutes; that is, for the lidocaine and mepivacaine solutions respectively, 91% and 95% of the subjects who reported lip numbness had onset within 4 minutes. Fifty-six percent of the subjects still had lip numbness at 60 minutes with the lidocaine solution, and 33% had lip numbness at 60 minutes with 3% mepivacaine. Coggins et al. 6 reported a 58% incidence of lip numbness with the IO injection of the mandibular first molar with 2% lidocaine with 1:100,000 epinephrine. In our study, we tested for lip numbness every 2 minutes whereas Coggins et al. 6 questioned the subjects regarding lip numbness at the end of the 60 minutes. This would likely account for the differences between the studies. The lower incidence of lip numbness with 3% mepivacaine was probably related to the lower efficacy of this drug when administered intraosseously. Although it is not known if the anesthetic solution de-
livered intraosseously can reach the inferior alveolar nerve, from the results of our study, we can speculate on a few observations. Because 50% to 76% had lip numbness, enough anesthetic reached the IAN to produce a changed sensation in at least half the subjects. In the other subjects, perhaps the dense layer of bone covering the IAN prevented any effect. 13 Even with lip numbness, it is not likely that the IAN was blocked by the IO injection given distal to the first molar. If it were blocked, we would expect a more pronounced anesthetic effect on the second premolar. The perforation site selection, as described in the Stabident instruction manual, allowed the perforation to be made through a minimal thickness of cortical bone and generally would be equidistant between adjacent root structures. In addition, the site is in attached gingiva that is less mobile than alveolar mucosa and allows an easier location for needle insertion. In three mandibular molars, the width of the attached gingiva was not adequate and the perforation site was moved 1 m m above the mucogingival line. The lack of healthy tissue, inadequate spacing of adjacent teeth, and periodontal pocketing would indicate that the injection be moved from the suggested site or possibly contraindicated all together. During perforation, the "breakthrough" represents the point at which the perforator enters cancellous
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ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY January 1997
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"fable III. Percentages and discomfort ratings for postinjection survey with the intraosseous injections Solution
Day 0* 2% Lidocaine (1:100,000)t 3% Mepivacaine Day 1 2% Lidocaine (1:100,000)? 3% Mepivacaine Day 2 2% Lidocaine (1:100,000)? 3% Mepivacaine Day 3 2% Lidocaine (1:100,000)? 3% Mepivacaine
None
Mild
Moderate
Severe
64% (27/42) 60% (25/42)
33% (14/42) 33% (14/42)
2% (1/42) 5% (2/42)
0% (0/42) 0% (0/42)
74% (31/42) 76% (32/42)
21% (9/42) 14% (6/42)
2% (1/42) 10% (4/42)
2% (1/42) 0% (0/42)
79% (33/42) 81% (34/42)
19% (8/42) 17% (7/42)
2% (1/42) 2% (1/42)
0% (0/42) 0% (0/42)
86% (36142) 90% (38/42)
12% (5/42) 5% (2/42)
2% (1/42) 5% (2/42)
0% (0/42) 0% (0/42)
*Rating at time subjective numbness wore off. ?There were no significant differences between the solutions (p < 0.05).
bone, and although present with most of the perforations, breakthrough did not occur in 12% (10 of 84) of the perforations. Coggins et al. 6 also reported that breakthrough did not always occur. The observation of no feeling of breakthrough may be related to a thick cortical bone or not placing the perforator at a right angle to the bone resulting in drilling through an additional thickness of cortical bone. If breakthrough is not noticed and the perforator meets significant resistance, it may be that it is hitting the root of an adjacent tooth. The perforator should be moved to another site. Reperforation was required in approximately 9% (8 of 84) of the subjects indicating that reperforation may be necessary in some mandibular molars. Three (4%) perforators separated from the base of the plastic shank during the study. They were easily removed with a hemostat. One separation occurred during a difficult perforation (dense cortical bone). Another separation occurred when air pressure to the handpiece was inadvertently shut off. The third occurred when the handpiece was allowed to stop rotating during perforation. None of the perforators broke, that is, there was no metal fracture. Needle insertion into the perforation site was rated, as difficult (needle entry along the same path of perforation took at least 10 seconds) in 19 of 84 subjects. Most of these instances occurred early in the study suggesting a learning curve. Careful visualization of the angle of perforation and mimicking this angle on needle insertion should prove helpful clinically. It has been reported that only light pressure is needed to inject solution into cancellous bone with the IO technique. 1, 3, 4, 6, 7 In this study, 19% (16 of 84) of the injections required greater than light finger pressure on the syringe handle to deposit the anesthetic solution. None of the needles demonstrated blockage. These cases can be explained by not perforating the
full depth of cortical bone or placement of the needle into a constricted cancellous or periodontal ligament space. For the infiltration and IO injections, the majority of the subjects rated pain as none to mild, with some reports of moderate pain (Table I). Similar results were reported by Coggins et al. 6 for the phases of the IO injection of the mandibular first molar, but they reported higher incidences of moderate pain for the infiltration injections. Because there were no significant differences between the solutions, we can conclude that they acted in a similar manner. Therefore the IO injection technique with either solution, when used as a primary injection, is not generally painful. Postinjection pain for the IO injection was rated as none to mild at the time subjective numbness wore off in 93% to 97% of the injections (Table III). The pain ratings generally decreased over the next 3 days. Similar results have been reported by Dunbar et al. 7 and Coggins et al. 6 at the mandibular first molar site after an IO injection. Because there were no significant differences between the solutions, it is reasonable to conclude that they acted similarly. Overall, the IO injection has a 2% to 10% potential for moderate postinjection pain; part of this pain may be related to postinjection sequelae. Although no animal study has investigated the effects of the Stabident IO injection on gingiva and bone, Dunbar et al. 7 and Coggins et al., 6 with the Stabident system, have reported swelling and purulence at IO injection sites. Generally, the incidence has been reported to be low (3%) 6, 7 as was found in this study (5% or 4 of 84 subjects). Two sites were probeable into bone to a depth of 10 ram. Sulcus depths and radiographic examination were within normal limits for all teeth. Two cases required antibiotic administration. By 14 days, all sites were healed except one that
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Volume 83, Number I
required 1 month for complete healing. The cause of this problem was likely gingival or bone trauma during perforation. Because there were no significant differences between the solutions (Table Ill), it is likely that the anesthetic solutions behaved in a similar manner in terms of postoperative healing. Although all areas healed, the possibility of swelling and exudate after IO injections must be considered with this injection technique. In the current study, two subjects (2%) also reported bruising and soreness at the site that resolved within 5 days, and one subject developed an apthous ulcer that resolved by day 12. These would be considered minor sequellae. Thirteen percent (11 of 84) of the subjects reported the experimental tooth "felt high" when chewing for a few days. Dunbar et al. 7 reported a 10% incidence and Coggins et al. 6 a 4% incidence in mandibular molars. This feeling is most likely an increased awareness to biting that results from soreness in the area caused by damage from perforation or inflammation of the bone. No subjects reported symptoms of a pulpal nature postoperatively. In conclusion, the primary IO injection of 2% lidocaine with 1:100,000 epinephrine was more successful and resulted in a longer duration of pulpal anesthesia than when 3% mepivacaine was used in noninflamed mandibular first molars. The majority of subjects had no pain or mild pain with perforation and solution deposition; 5% of the subjects had slow healing perforation sites. REFERENCES 1. Magnes G. Intraosseous anesthesia. Anesth Prog 1968;15: 264-7.
2. Bourke K. Intraosseous anesthesia. Dent Anaesth Sed 1974;3: 13-9. 3. Lilienthal B. A clinical appraisal of intraosseous dental anesthesia. Oral Surg Oral Med Oral Pathol 1975;39:692-7. 4. Pearce J. Intraosseous injection for profound anesthesia of the lower molar. J Colo Dent Assoc 1976;54:25-6. 5. Leonard M. The efficacy of an intraosseous injection system of delivering local anesthetic. J Am Dent Assoc 1995;I26: 81-6. 6. Coggins R, Reader A, Nist R, Beck M, Meyers W. Anesthetic efficacy of the intraosseous injection in maxillary and mandibular teeth. Oral Surg Oral Med Oral Pathol 1996;81:63441. 7. Dunbar D, Reader A, Nist R, Beck M, Meyers W. The anesthetic efficacy of the intraosseous injection after an inferior alveolar nerve block. J Eudodon 1996;22:481-6. 8. Schleder J, Reader A, Beck M, Meyers W. The periodontal ligament injection: a comparison of 2% lidocaine, 3% mepivacaine, and 1:100,000 epinephrine to 2% lidocaine with 1:100,000 epinephrine in human mandibular premolars. J Endodon 1988;14:397-404. 9. Johnson GK, Hlava GL, Kalkwarf KL. A comparison of periodontal intraligamental anesthesia using etidocaine HCL and lidocaine HCL. Anesth Prog 1985;32:202-5. 10. Kaufman E, LeResche L, Sommers E, Dworkin SF, Truelove EL. Intraligamentary anesthesia:a double-blind comparative study. J Am Dent Assoc 1984;108:175-8. 11. Gray RJM, Lomax AM, Rood JP. Periodontal ligament injection: alternative solutions, Anesth Prog 1990;37:293-5. 12. Nusstein J, Reader A, Nist R, Beck M, Meyers W. The anesthetic efficacy of the intraosseous injection in irreversible pulpitis. J Endodon 1996;22:196 (abstract). 13. Denio D, Torabinejad M, Bakland LK. Anatomical relationship of the mandibular canal to its surrounding structures in mature mandibles. J Endodon 1992;18:161-5.
Reprint requests: A1 Reader, DDS, MS College of Dentistry Division of Endodontics The Ohio State University 305 W. 12th Ave. Columbus, OH 43210-1241
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Anesthetic efficacy of the intraosseous injection of 2% lidocaine (1:100,000 epinephrine) and 3 % mepivacaine in mandibular first molars K a r a n R e p l o g l e , D D S , M S , a A1 Reader, D D S , M S , b R o b e r t Nist, D D S , M S , c M i k e Beck, D D S , M A , a Joel W e a v e r , D D S , PhD, e and W i l l i a m J. M e y e r s , D M D , M E d , f C o l u m b u s , O h i o THE OHIO STATE UNIVERSITY
Objectives. This study compared the anesthetic efficacy of a primary intraosseous injection of 2% lidocaine with 1:100,000 epinephrine and 3% mepivacaine in human mandibular first molars. Injection pain and healing postoperatively were also assessed for the intraosseous injection. Study design. With the use of a repeated-measures design, 42 subjects randomly received intraosseous injections of 1.8 ml of 2% lidocaine with 1:100,000 epinephrine or 1.8 ml of 3% mepivacaine in a double-blind manner at two successive appointments. ,The fi!~t molar and adjacent teeth were blindly tested with an electric pulp tester at 2-minute cycles for 60 minutes. Anesthetic success was defined as no subject response to the maximum output of the pulp tester (80 reading) for two consecutive readings. Results. Anesthetic success occurred in 74% of the first molars with 2% ]idocaine with 1:100,000 epinephrine and in 45% with 3% mepivacaine. The difference was statistically significant (p < 0.05). Overall, onset was rapid for the intraosseous injections, the duration of pulpal anesthesia steadily declined over the 60 minutes, the majority of the subjects had no pain or mi[d pain with perforation and solution deposition, and 5% of the subjects had delayed healing at the perforation sites. Conclusions. The results of this study indicate that the primary intraosseous injection of 2% [idocaine with 1:100,000 epinephrine is more successful and results in a longer duration of pulpal anesthesia as compared with 3% mepivacaine in noninflamed mandibular first molars. Most subjects reported no or mild pain during perforation and injection. (Oral Surg Oral Med Oral Patho| Oral Radiol Fndod 1997;83:30-7)
T h e intraosseous (IO) injection a l l o w s p l a c e m e n t o f a local anesthetic solution directly into the c a n c e l l o u s b o n e a d j a c e n t to the tooth to be anesthetized. Historically, various m e t h o d s o f a c c e s s i n g the c a n c e l l o u s Study was supported by Graduate Endodontic Research Fund. aFormer Graduate Student in Endodontics. bProfessor and Program Director, Division of Endodontics. °Associate Clinical Professor, Division of Endodontics. aAssociate Professor, Department of Health Services Research. eAssociate Professor, Department of Oral and Maxillofacial Surgery. fFormer Chairman and Professor, Department of Endodontics/Diagnostic Services. Submitted for publication May 10, 1996; returned for revision JulY 16, 1996; accepted for publication Aug. 27, 1996. Copyright © 1997 by Mosby-Year Book, Inc. 1079-2104/97/$5.00 + 0 7/15/77717 30
space h a v e i n c l u d e d drilling a hole t h r o u g h the cortical b o n e using a r o u n d bur, drill, or e n d o d o n t i c reamer. 1-4 Currently, there is an IO s y s t e m m a r k e t e d under the trade n a m e S t a b i d e n t (Fairfax D e n t a l Inc., M i a m i , Fla.). This s y s t e m is c o m p r i s e d o f a slows p e e d h a n d p i e c e - d r i v e n p e r f o r a t o r (a solid 2 7 - g a u g e w i r e with a b e v e l e d end) that w h e n activated drills a small h o l e through the cortical plate. T h e anesthetic solution is d e l i v e r e d to cancellous b o n e through a 2 7 - g a u g e ultrashort injector n e e d l e p l a c e d into the hole m a d e b y the perforator. The S t a b i d e n t I O injection has been e v a l u a t e d as a p r i m a r y and s u p p l e m e n t a l injection. In a clinical study, L e o n a r d 5 r e p o r t e d a 90% success rate for extractions with this system. In an e x p e r i m e n t a l study, C o g g i n s et al. 6 u s e d the S t a b i d e n t s y s t e m as a p r i m a r y
ORAL'SURGERY ORAL MEDICINE ORAL PATHOLOGY
Replogle et al.
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Volume 83, Number I
injection in various groups of maxillary and mandibular teeth. They reported success rates of 75% for the mandibular first molar, 93% for the maxillary first molar, 7 8 % for the mandibular lateral incisor, and 90% for the maxillary lateral incisor with 1.8 ml of 2% lidocaine with 1:100,000 epinephrine. Dunbar et al. 7 evaluated the Stabident system in mandibular first molars as a supplemental injection to the inferior alveolar nerve (IAN) block. They recorded a high incidence (98%) of pulpal anesthesia with the combination IO/IAN technique. Although the IO injection has been studied clinically and experimentally, no objective study has evaluated the IO Stabident technique as a primary injection with 3% mepivacaine. The purpose of this study was to compare the anesthetic efficacy of an IO injection of 2% lidocaine with 1:100,000 epinephrine versus 3% mepivacaine in human mandibular first molars, Injection pain and healing postoperatively were also assessed for the IO injection. MATERIAL A N D METHODS Forty-two adult subjects, 25 men and 17 women, from age 18 to 39 years with an average age of 25 years, participated. The subjects were in good health and not taking any medications that would alter pain perception. The study was approved by The Ohio State University Human Subjects Review Committee; written informed consent was obtained from each subject. Forty-four IO injections were administered to the right mandible and 40 to the left mandible. The mandibular first molar, second molar, and second premolar were chosen as the test teeth. The contralateral canine was used as the unanesthetized control to ensure that the pulp tester was operating properly and that the subject 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. Two appointments at least 2 weeks apart were scheduled for each of the 42 subjects. With a repeated-measures design, each subject randomly received either an IO injection of 1.8 ml of 2% lidocaine with 1:100,000 epinephrine or 1.8 ml of 3% mepivacaine at the two successive appointments. The solution not administered at the first appointment was given atthe second appointment. To effectively blind the operator and subject to the solutions administered, each anesthetic cartridge (lidocaine or mepivacaine) was masked with a white opaque label and numbered to determine the order of anesthetic administration. A trained assistant loaded each syringe before the appointment.
At each appointment and before injection, the first molar, mesial, and distal adjacent teeth, and control canine were tested three times with an electric 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 occlusal edge. The current rate of the pulp tester was set at 25 seconds to increase from no output (0) to the m a x i m u m output of 80. The number at initial sensation was recorded. All preinjection and postinjection tests were performed by trained personnel who were blinded to the anesthetic solutions administered. The IO injection was given with the Stabident system. With the subjects in a reclining position, the area of perforation was determined with the horizontal line of the buccal gingival margins of the first molar and adjacent teeth and a vertical line that passed through the interdental papilla on the distal aspect of the first molar. A point approximately 2 m m below the intersection of these lines was selected as the perforation site if the site was in attached gingiva. If this point was in alveolar mucosa (three subjects), the injection site was moved 1 m m above the junction of the attached gingiva and alveolar mucosa. The soft tissue at the determined perforation site was anesthetized with an infiltration of approximately 0.1 ml of either 2% lidocaine with 1:100,000 epinephrine (Astra Pharmaceutical Products, Westboro, Mass.) or 3% mepivacalne (Cook-Waite, Seattle, Wash.) deposited through a 30-gauge needle attached to a standard aspirating syringe. These cartridges were also blinded and were loaded into separate syringes. The cortical bone was then perforated with the Stabident perforator (a beveled-ended solid wire attached to a plastic hub) in a contra-angle, slow-speed handpiece. The perforator was placed through the gingiva at the infiltration site and was oriented perpendicular to the cortical plate. With the point gently resting against bone, the handpiece was activated in a series of short bursts with light pressure until a "breakthrough" feeling was observed or until 2 to 5 seconds had elapsed. Before inserting the 27-gauge ultrashort Stabident needle through the perforation, the needle was bent at the hub to a 45-degree angle to allow for ease of insertion. When bleeding obscured the perforation site, the area was blotted with a sterile cotton roll to control hemorrhage and to identify the perforation site. The standard syringe was held in a "pengripping" fashion, and the needle was inserted into the perforation site and 1.8 ml of 2% lidocaine with 1:100,000 epinephrine or 3% mepivacaine was delivered over a 2-minute time period. If back-pressure
32
Replogle et aL
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY
January 1997 Table I. Percentages and discomfort ratings of infiltration and intraosseous injections Injection Phase/Solution
Infiltration Injection* 2% Lidocaine (1:100,000) 3% Mepivacaine Intraosseous Injection* Perforation 2% Lidocaine (1:100,000) 3% Mepivacaine Needle insertion 2% Lidocaine (1:100,000) 3% Mepivacaine Solution deposition 2% Lidocaine (1:100,000) 3% Mepivacaine
None
Mild
Moderate
Severe
52% (22/42) 43% (18/42)
45% (19/42) 55% (23/42)
2% (1/42) 2% (1/42)
0% (0/42) 0% (0/42)
83% (35/42) 86% (36/42)
10% (4/42) 5% (2/42)
7% (3/42) 0% (0/40)
0% (0/42) 0% (0/42)
95% (40/42) 83% (35/40)
5% (2/42) 17% (7/42)
0% (0/42) 2% (1/42)
0% (0/42) 0% (0/42)
79% (33/42) 55% (23/42)
19% (8/42) 36% (15/42)
2% (1/42) 7% (3/42)
0% (0/42) 2% (1/42)
*There were no significant differences between the solutions (p > 0.05).
Table II. Percentages and number of subjects who experienced anesthetic success and failure Solution/Tooth
2% Lidocaine (1:100,000) Mandibular second molar Mandibular first molar* Mandibular second premolar 3% Mepivacaine Mandibular second molar Mandibular first molar* Mandibular second premolar
Success
Failure
76% (32/42) 74% (31/42) 57% (24/42)
24% (10/42) 26% (11/42) 43% (18/42)
67% (28/42) 45% (19/42)? 41% (17/42)
33% (14/42) 55% (23/42)? 59% (25/42)
*Experimental Tooth ?Statistically significant difference beween solutions (p < 0.05).
(defined as greater than light finger pressure on the syringe handle to deliver the solution) was encountered on solution deposition, the needle was rotated approximately a quarter turn and deposition was reattempted. If this was not successful, the needle was removed and checked for blockage. If not blocked, it was reinserted or the site was reperforated with a new perforator and the injection completed. The subjects were instructed to rate the pain of the infiltration and IO injections. The rating scale was: 0, no pain; 1, mild pain (pain that is recognizable but not discomforting); 2, moderate pain (pain that is discomforting but bearable); and 3, severe pain (pain that causes considerable discomfort and is difficult to bear). At 1 minute after the IO injection, the first molar and adjacent distal tooth were pulp tested. At 2 minutes, the adjacent mesial tooth and contralateral control canine were tested. This cycle of testing was repeated every 2 minutes. The control canine was tested every third cycle with an inactive pulp tester to test the reliability of the subject. All testing was stopped at 60 minutes after injection.
No subject response to the m a x i m u m output (80 reading) of the pulp tester was used as the criterion for pulpal anesthesia. Anesthesia was considered successful when two consecutive 80 readings were obtained at any time during the 60 minutes. Anesthesia was considered a failure if the subject never achieved two consecutive 80 readings during the 60 minutes. Onset and duration of subjective lip anesthesia was monitored by asking the question " I s your lip n u m b ? " at each minute for 60 minutes. A postinjection questionnaire asked the subjects to rate the pain and any side effects in the area of the IO injection at the time initial numbness wore off and in the morning for 3 days after the appointment. Between-solution differences in incidence of pulpal anesthesia (80 readings), success, and failure were analyzed nonparametrically with Bonferroni adjusted M c N e m a r tests. Differences in pain ratings for infiltration, IO injections, and postoperative scores were analyzed with Wilcoxon's matched pairs, signed rank test. Comparisons were considered significant at p < 0.05.
RESULTS The discomfort ratings for the infiltration and IO injections are presented in Table I. Generally, the infiltration and intraosseous injections resulted in none or mild pain ratings the majority o f the time. There were no significant differences between the solutions (p > 0.05). Anesthetic success and failure are presented in Table II. For the mandibular first molar, success was 74% with 2% lidocaine (1:100,000 epinephrine), and success for 3% mepivacaine was 45%. There was a statistically significant difference between the solutions (p < 0.05). The incidence of pulpal anesthesia and significant
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY
Replogle et al.
513
Volume 83, Number 1
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differences between solutions for the mandibular first molar are presented in Fig. 1. Statistical differences were shown from 8 through 30 minutes and at 40 minutes when comparing the two solutions. Incidence of anesthesia for the adjacent teeth are presented in Figs. 2 and 3. The postinjection discomfort ratings for the IO injections are presented in Table III. Postinjection pain was rated as none to mild in 93% to 97% of the injections; pain ratings decreased over the next 3 days (Table III). There were no significant differences between the solutions (p > 0.05). There was a 5% (4 of 84) incidence of postinjection swelling or exudate at the IO injection site. Thirteen percent (11 of 84) of the subjects reported the experimental tooth felt high when chewing.
DISCUSSION The anesthetic success rate in this study (74%) was similar to the results of Coggins et al. 6 who also used 2% lidocaine with 1:100,000 epinephrine for the primary IO injection of mandibular first molars. They reported a 75% success rate. The lack of 100% success may be related to a thick or dense cortical bone preventing perforation into cancellous bone or limited anesthetic solution distribution because of a constricted cancellous space. The IO injection of 2%
lidocaine with 1:100,000 epinephrine may provide pulpal anesthesia in approximately 75% of noninflamed mandibular first molars when used as a primary technique. The anesthetic success rate (45%) with 3% mepivacaine was lower as compared with the lidocaine solution (74%) (Table II). Previous studies 8-11 on the periodontal ligament injection (a type of IO injection) have also shown lower success rates when using anesthetic solutions that do not contain vasoconstrictors or have reduced vasoconstrictor concentrations. Therefore when 3% mepivacaine is used as a primary injection intraosseously, approximately 45% of the patients will have pulpal anesthesia. As shown in Fig. 1 for the first molar, onset of anesthesia (highest percentage of initial 80 readings) occurred within the first three testing times (6 minutes) for both solutions. Therefore onset of anesthesia was rapid for the IO injection. Coggins et al. 6 also reported rapid onset of anesthesia with the IO injection. Duration of anesthesia for both solutions steadily declined over the 60 minutes (Fig. 1). At 20 minutes, 62% of the subjects had pulpal anesthesia with 2% lidocaine (1:100,000 epinephrine) and only 24% with 3% mepivacaine. At 30 minutes, 52% of the subjects had pulpal anesthesia with the lidocaine solution and
34
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY January 1997
Replogle et al.
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17% with 3% mepivacaine. At 45 minutes, 29% of the subjects had pulpal anesthesia with the lidocaine solution and 7% with 3% mepivacaine. When 2% lidocaine with 1:100,000 epinephrine was compared with 3% mepivacaine, the incidence of pulpal anesthesia was statistically significant at 8 through 30 minutes as well as at 40 minutes (Fig. 1). Therefore for those patients who achieve pulpal anesthesia, 2% lidocaine (1:100,000 epinephrine) may provide anesthesia for procedures of short duration as demonstrated by Leonard. 5 Three percent mepivacaine will provide an even shorter duration of pulpal anesthesia. Considering the success rates and duration of the primary I t injections in this study, the true value of the I t injection may be its use as a supplemental injection. Dunbar et al.7 demonstrated that when the I t injection was added to the I A N block a high incidence (98%) of pulpal anesthesia was obtained; 90% of the first molars were still anesthetized at 60 minutes. Nusstein et al. az found a supplemental I t injection was 88% successful in providing profound pulpal anesthesia in posterior teeth diagnosed with irreversible pulpitis. Both of these studies used 2% lidocaine with 1:100,000 epinephrine. The efficacy of 3% mepivacaine as a supplemental injection is not known and is currently under investigation. Although the Stabident manual suggests that 0.9 ml
of solution be deposited to anesthetize three adjacent teeth, no studies have been performed to support this statement. We used 1.8 ml of both solutions to evaluate the effect this volume has on pulpal anesthesia. With this as a guideline, future studies may address reduced amounts of solution. Anesthesia of adjacent teeth is presented in Table II and Figs. 2 and 3. For the second molar, anesthetic success, failure, and the incidence of pulpal anesthesia were fairly similar between the experimental first molar and this distal adjacent tooth for the two solutions. Coggins et al. 6 reported comparable results in his study of mandibular molars. Generally, for the second molar, a mesial I t injection (distal injection to the experimental first molar) of either solution would result in a similar incidence o f pulpal anesthesia as the first molar. The success rates and incidence of pulpal anesthesia for the adjacent mesial tooth were lower than the experimental tooth (Table II and Figs. 2 and 3). Similar results were reported by Dunbar et al. 7 and Coggins et al. 6 The most likely reason for the difference between mesial and distal teeth is the selection of the distal I t injection site. To provide an equal anesthetic effect for the mesial tooth, the solution would have to spread past the experimental tooth or block the nerve trunk near to or at the site of injection. Because neither occurred readily enough to
ORAL SURGERYORAL MEDICINE ORAL PATHOLOGY
Replogle et al.
35
Volume 83, Number 1
100 • 2 ~ Lidocaine {1:100,000) • 3~ Mepivacaine I/}
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Time (minutes) Fig. 3. Incidence of anesthesia for mandibular second premolar as determined by lack of response to electric pulp testing at maximal setting (percentage of 80/80s) at each postinjection time interval. There were no significant differences (p > 0.05) between 2% lidocaine (1:100,000) and 3% mepivacaine.
result in anesthesia of the mesial tooth at a level equal to the experimental tooth, an IO injection distal to the mesial tooth may result in better anesthesia of the mesial tooth. Subjective assessment of lip anesthesia after the IO injection of the mandibular first molar showed that 76% (32 of 42) of the subjects had "lip n u m b n e s s " with the lidocaine solution and 50% (21 of 42) with the mepivacaine solution. Onset of lip numbness occurred within 2 to 4 minutes; that is, for the lidocaine and mepivacaine solutions respectively, 91% and 95% of the subjects who reported lip numbness had onset within 4 minutes. Fifty-six percent of the subjects still had lip numbness at 60 minutes with the lidocaine solution, and 33% had lip numbness at 60 minutes with 3% mepivacaine. Coggins et al. 6 reported a 58% incidence of lip numbness with the IO injection of the mandibular first molar with 2% lidocaine with 1:100,000 epinephrine. In our study, we tested for lip numbness every 2 minutes whereas Coggins et al. 6 questioned the subjects regarding lip numbness at the end of the 60 minutes. This would likely account for the differences between the studies. The lower incidence of lip numbness with 3% mepivacaine was probably related to the lower efficacy of this drug when administered intraosseously. Although it is not known if the anesthetic solution de-
livered intraosseously can reach the inferior alveolar nerve, from the results of our study, we can speculate on a few observations. Because 50% to 76% had lip numbness, enough anesthetic reached the IAN to produce a changed sensation in at least half the subjects. In the other subjects, perhaps the dense layer of bone covering the IAN prevented any effect. 13 Even with lip numbness, it is not likely that the IAN was blocked by the IO injection given distal to the first molar. If it were blocked, we would expect a more pronounced anesthetic effect on the second premolar. The perforation site selection, as described in the Stabident instruction manual, allowed the perforation to be made through a minimal thickness of cortical bone and generally would be equidistant between adjacent root structures. In addition, the site is in attached gingiva that is less mobile than alveolar mucosa and allows an easier location for needle insertion. In three mandibular molars, the width of the attached gingiva was not adequate and the perforation site was moved 1 m m above the mucogingival line. The lack of healthy tissue, inadequate spacing of adjacent teeth, and periodontal pocketing would indicate that the injection be moved from the suggested site or possibly contraindicated all together. During perforation, the "breakthrough" represents the point at which the perforator enters cancellous
36
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY January 1997
Replogle et aI.
"fable III. Percentages and discomfort ratings for postinjection survey with the intraosseous injections Solution
Day 0* 2% Lidocaine (1:100,000)t 3% Mepivacaine Day 1 2% Lidocaine (1:100,000)? 3% Mepivacaine Day 2 2% Lidocaine (1:100,000)? 3% Mepivacaine Day 3 2% Lidocaine (1:100,000)? 3% Mepivacaine
None
Mild
Moderate
Severe
64% (27/42) 60% (25/42)
33% (14/42) 33% (14/42)
2% (1/42) 5% (2/42)
0% (0/42) 0% (0/42)
74% (31/42) 76% (32/42)
21% (9/42) 14% (6/42)
2% (1/42) 10% (4/42)
2% (1/42) 0% (0/42)
79% (33/42) 81% (34/42)
19% (8/42) 17% (7/42)
2% (1/42) 2% (1/42)
0% (0/42) 0% (0/42)
86% (36142) 90% (38/42)
12% (5/42) 5% (2/42)
2% (1/42) 5% (2/42)
0% (0/42) 0% (0/42)
*Rating at time subjective numbness wore off. ?There were no significant differences between the solutions (p < 0.05).
bone, and although present with most of the perforations, breakthrough did not occur in 12% (10 of 84) of the perforations. Coggins et al. 6 also reported that breakthrough did not always occur. The observation of no feeling of breakthrough may be related to a thick cortical bone or not placing the perforator at a right angle to the bone resulting in drilling through an additional thickness of cortical bone. If breakthrough is not noticed and the perforator meets significant resistance, it may be that it is hitting the root of an adjacent tooth. The perforator should be moved to another site. Reperforation was required in approximately 9% (8 of 84) of the subjects indicating that reperforation may be necessary in some mandibular molars. Three (4%) perforators separated from the base of the plastic shank during the study. They were easily removed with a hemostat. One separation occurred during a difficult perforation (dense cortical bone). Another separation occurred when air pressure to the handpiece was inadvertently shut off. The third occurred when the handpiece was allowed to stop rotating during perforation. None of the perforators broke, that is, there was no metal fracture. Needle insertion into the perforation site was rated, as difficult (needle entry along the same path of perforation took at least 10 seconds) in 19 of 84 subjects. Most of these instances occurred early in the study suggesting a learning curve. Careful visualization of the angle of perforation and mimicking this angle on needle insertion should prove helpful clinically. It has been reported that only light pressure is needed to inject solution into cancellous bone with the IO technique. 1, 3, 4, 6, 7 In this study, 19% (16 of 84) of the injections required greater than light finger pressure on the syringe handle to deposit the anesthetic solution. None of the needles demonstrated blockage. These cases can be explained by not perforating the
full depth of cortical bone or placement of the needle into a constricted cancellous or periodontal ligament space. For the infiltration and IO injections, the majority of the subjects rated pain as none to mild, with some reports of moderate pain (Table I). Similar results were reported by Coggins et al. 6 for the phases of the IO injection of the mandibular first molar, but they reported higher incidences of moderate pain for the infiltration injections. Because there were no significant differences between the solutions, we can conclude that they acted in a similar manner. Therefore the IO injection technique with either solution, when used as a primary injection, is not generally painful. Postinjection pain for the IO injection was rated as none to mild at the time subjective numbness wore off in 93% to 97% of the injections (Table III). The pain ratings generally decreased over the next 3 days. Similar results have been reported by Dunbar et al. 7 and Coggins et al. 6 at the mandibular first molar site after an IO injection. Because there were no significant differences between the solutions, it is reasonable to conclude that they acted similarly. Overall, the IO injection has a 2% to 10% potential for moderate postinjection pain; part of this pain may be related to postinjection sequelae. Although no animal study has investigated the effects of the Stabident IO injection on gingiva and bone, Dunbar et al. 7 and Coggins et al., 6 with the Stabident system, have reported swelling and purulence at IO injection sites. Generally, the incidence has been reported to be low (3%) 6, 7 as was found in this study (5% or 4 of 84 subjects). Two sites were probeable into bone to a depth of 10 ram. Sulcus depths and radiographic examination were within normal limits for all teeth. Two cases required antibiotic administration. By 14 days, all sites were healed except one that
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required 1 month for complete healing. The cause of this problem was likely gingival or bone trauma during perforation. Because there were no significant differences between the solutions (Table Ill), it is likely that the anesthetic solutions behaved in a similar manner in terms of postoperative healing. Although all areas healed, the possibility of swelling and exudate after IO injections must be considered with this injection technique. In the current study, two subjects (2%) also reported bruising and soreness at the site that resolved within 5 days, and one subject developed an apthous ulcer that resolved by day 12. These would be considered minor sequellae. Thirteen percent (11 of 84) of the subjects reported the experimental tooth "felt high" when chewing for a few days. Dunbar et al. 7 reported a 10% incidence and Coggins et al. 6 a 4% incidence in mandibular molars. This feeling is most likely an increased awareness to biting that results from soreness in the area caused by damage from perforation or inflammation of the bone. No subjects reported symptoms of a pulpal nature postoperatively. In conclusion, the primary IO injection of 2% lidocaine with 1:100,000 epinephrine was more successful and resulted in a longer duration of pulpal anesthesia than when 3% mepivacaine was used in noninflamed mandibular first molars. The majority of subjects had no pain or mild pain with perforation and solution deposition; 5% of the subjects had slow healing perforation sites. REFERENCES 1. Magnes G. Intraosseous anesthesia. Anesth Prog 1968;15: 264-7.
2. Bourke K. Intraosseous anesthesia. Dent Anaesth Sed 1974;3: 13-9. 3. Lilienthal B. A clinical appraisal of intraosseous dental anesthesia. Oral Surg Oral Med Oral Pathol 1975;39:692-7. 4. Pearce J. Intraosseous injection for profound anesthesia of the lower molar. J Colo Dent Assoc 1976;54:25-6. 5. Leonard M. The efficacy of an intraosseous injection system of delivering local anesthetic. J Am Dent Assoc 1995;I26: 81-6. 6. Coggins R, Reader A, Nist R, Beck M, Meyers W. Anesthetic efficacy of the intraosseous injection in maxillary and mandibular teeth. Oral Surg Oral Med Oral Pathol 1996;81:63441. 7. Dunbar D, Reader A, Nist R, Beck M, Meyers W. The anesthetic efficacy of the intraosseous injection after an inferior alveolar nerve block. J Eudodon 1996;22:481-6. 8. Schleder J, Reader A, Beck M, Meyers W. The periodontal ligament injection: a comparison of 2% lidocaine, 3% mepivacaine, and 1:100,000 epinephrine to 2% lidocaine with 1:100,000 epinephrine in human mandibular premolars. J Endodon 1988;14:397-404. 9. Johnson GK, Hlava GL, Kalkwarf KL. A comparison of periodontal intraligamental anesthesia using etidocaine HCL and lidocaine HCL. Anesth Prog 1985;32:202-5. 10. Kaufman E, LeResche L, Sommers E, Dworkin SF, Truelove EL. Intraligamentary anesthesia:a double-blind comparative study. J Am Dent Assoc 1984;108:175-8. 11. Gray RJM, Lomax AM, Rood JP. Periodontal ligament injection: alternative solutions, Anesth Prog 1990;37:293-5. 12. Nusstein J, Reader A, Nist R, Beck M, Meyers W. The anesthetic efficacy of the intraosseous injection in irreversible pulpitis. J Endodon 1996;22:196 (abstract). 13. Denio D, Torabinejad M, Bakland LK. Anatomical relationship of the mandibular canal to its surrounding structures in mature mandibles. J Endodon 1992;18:161-5.
Reprint requests: A1 Reader, DDS, MS College of Dentistry Division of Endodontics The Ohio State University 305 W. 12th Ave. Columbus, OH 43210-1241