Anesthetic efficacy of X-tip intraosseous injection using 2% lidocaine with 1:80,000 epinephrine in patients with irreversible pulpitis after inferior alveolar nerve block: A clinical study.

INTRODUCTION: The inferior alveolar nerve block (IAN) is the most frequently used mandibular injection technique for achieving local anesthesia in endodontics. Supplemental injections are essential to overcome failure of IAN block in patients with irreversible pulpitis. AIM: To evaluate the anesthetic efficacy of X-tip intraosseous injection (2% lidocaine with 1:80,000 epinephrine) in patients with irreversible pulpitis in mandibular posterior teeth when conventional IAN block failed.
MATERIALS AND METHODS: Thirty emergency patients diagnosed with irreversible pulpitis in a mandibular posterior tooth received an IAN block and experienced moderate to severe pain on endodontic access or initial instrumentation. The X-tip system was used to administer 1.8 ml of 2% lidocaine with 1:80,000 epinephrine. The success of X-tip intraosseous injection was defined as none or mild pain (Heft-Parker visual analogue scale ratings < 54 mm) on endodontic access or initial instrumentation.
RESULTS: Ninety-three percent of X-tip injections were successful and 7% were unsuccessful. Discomfort rating for X-tip perforation: 96.66% patients reported none or mild pain, whereas 3.34% reported moderate to severe pain. For discomfort rating during solution deposition, 74.99% patients reported none or mild pain and 24.92% reported moderate to severe pain. Ninety-six percent of the patients had subjective/objective increase in heart rate.
CONCLUSIONS: Supplemental X-tip intraosseous injection using 2% lignocaine with 1:80,000 epinephrine has a statistically significant influence in achieving pulpal anesthesia in patients with irreversible pulpitis.

INTRODUCTION

Safe and effective pain control is essential for today's dental practice. Local anesthesia is the primary method used in dentistry for the management of procedural pain.[1] Local anesthetics administered by the infiltration route of injection are highly effective in producing clinical anesthesia in normal tissues.[2] Nerve block injections are considered more technically difficult, and somewhat less predictable than infiltration injections. Clinical studies suggest success rates of about 75-90% or more in patients with clinically normal teeth.[3-9] In previous studies,[4] patients with irreversible pulpitis had an eight-fold higher failure of local anesthetic injections in comparison with normal control patients. Thus, local anesthetic failures can occur in a substantial proportion of endodontic patients. Hence, a common clinical problem is the difficulty experienced in obtaining satisfactory anesthesia of an acutely painful inflamed tooth (irreversible pulpitis) by means of regional block.[10]

Supplemental injections are essential in patients with irreversible pulpitis when pulpal anesthesia from inferior alveolar nerve (IAN) block is inadequate and the pain is too severe to proceed for an endodontic treatment. Studies have shown success rates of only 19-56% for IAN blocks in patients with irreversible pulpitis.[11-16] The Stabident or X-tip intraosseous injection allows placement of a local anesthetic solution directly into the cancellous bone adjacent to the tooth to be anesthetized. Success of these supplemental intraosseous injections in achieving pulpal anesthesia in patients with irreversible pulpitis has been reported to be 82-98%.[11-1317]

The X-tip anesthesia delivery system consists of an X-tip that separates into two parts: The drill and guide-sleeve component [Figure 1a]. The drill (a special hollow needle) leads the guide-sleeve through the cortical plate, where it is separated and withdrawn. The remaining guide-sleeve is designed to accept a 27-gauge needle to inject the anesthetic solution. The guide sleeve is removed after the intraosseous injection is complete.

Figure 1

(a) The X-tip anesthetic delivery system consists of an X-tip (top) that separates into two parts: Drill and guide-sleeve component (bottom), (b) Heft-Parker visual analogue scale (VAS) pain scale used for assessment of pain, the millimeter demarcations were not shown on the patients VAS

The purpose of this study was to determine the anesthetic efficacy of supplemental intraosseous injection using the X-tip system in an apical location in mandibular posterior teeth with irreversible pulpitis when conventional IAN block failed. The second purpose of the study was to evaluate discomfort rating during administration of an intraosseous injection and to study the effect of intraosseous injection on heart rate.

MATERIALS AND METHODS

Thirty patients with endodontic emergency, 16 males and 14 females aged between 18 years and 40 years, with a diagnosis of symptomatic irreversible pulpitis of mandibular posterior teeth were selected for the study. All patients were in good generalized medical health as determined by a health history and oral questioning. The Ethical Committee approved the study and written informed consent was obtained from each patient.

To qualify for the study, each patient had a vital mandibular posterior tooth, was actively experiencing pain and had prolonged response to cold testing with ice. Patients with no response to cold testing or periradicular pathosis and patients with compromised medical health were excluded from the study. Therefore, every selected patient had a tooth that fulfilled the criteria for a clinical diagnosis of irreversible pulpitis. Additionally, all teeth had vital coronal pulp tissue on endodontic access. Patients received IAN blocks using 2% lidocaine with 1:80,000 epinephrine (Lignospan, Septodont, France) along with long buccal injection. For IAN block, a syringe with 15/8 inch 25-gauge needle is inserted parallel to the occlusal plane of the mandibular teeth from the opposite side of the mouth at a level bisecting the finger or thumbnail, penetrating the tissues of the pterygotemporal depression and entering the pterygomandibular space. The needle is penetrated into the tissues until gently contacting bone on internal surface of the ramus of mandible. The needle is then withdrawn 1 mm and 1-1.8 ml of solution is deposited slowly (1½-2 min). The needle is then withdrawn slowly about one half of its inserted depth and the remainder of the solution is injected in this area to anesthetize the lingual nerve. At 15 min after IAN block, the teeth were isolated with a rubber dam and standard endodontic access was performed. Patients were instructed to rate any discomfort during access using a Heft-Parker visual analogue scale (HP VAS).[18]

The HP VAS, with 170 mm, was divided into four categories. No pain corresponded to 0 mm. Mild pain was greater than 0 mm and less than or equal to 54 mm. Mild pain included descriptors of faint, weak and mild pain. Moderate pain was greater than 54 mm and less than 114 mm. Severe pain was greater than or equal to 114 mm. Severe pain included descriptors of strong, intense and maximum possible [Figure 1b]. All 30 patients had moderate or severe pain (HP VAS rating > 54 mm) on access into dentin, when entering the pulp chamber or with initial file placement, and received a supplemental intraosseous X-tip injection.

After rubber dam removal, the area of perforation was determined in the attached gingiva 2-4 mm apical to the crestal bone level according to the manufacturer's instructions (X-tip instruction manual) at a site distal or mesial to the operating tooth. Level of crestal bone was determined by sounding with a periodontal probe. After determination of the perforation site, the perforator was pushed through the attached gingiva until the X-tip contacted bone [Figure 2a]. Holding the drill at a 90° angle to the bone surface, the slow-speed micromotor handpiece was activated in a series of short bursts, using light pressure, until a “break through” feeling was observed. After perforation, the drill was withdrawn from the guide sleeve, leaving the guide sleeve in place [Figure 2b].

Figure 2

(a) Perforation into the bone with X-tip perforator, (b) Guide sleeve in place, (c) Delivering the anesthetic solution

The 27-gauge ultrashort X-tip needle was inserted into the guide sleeve and 1.8 ml of 2% lidocaine with 1:80,000 epinephrine (Lignospan Special, Septodont, France) was delivered over a 1-min time period [Figure 2c]. On complete deposition of solution, the guide sleeve was removed using a hemostat. After rubber dam placement, endodontic access was continued.

Success of supplemental X-tip technique is defined as “the ability to access the pulp chamber, to place initial files, and instrument the tooth without pain (HP VAS score of zero) or mild pain (HP VAS score less than or equal to 54 mm).”[17] If the patient had moderate to severe pain (HP VAS score greater than 54 mm) during access or initial instrumentation, the X-tip technique was judged as failure and the other methods were used to overcome the pulpal pain, which were successful. Before administering intraosseous X-tip injection, patients were instructed to rate the pain during perforation and solution deposition with the X-tip technique. The HP VAS was also used for the pain ratings. Subjective increase in heart rate were monitored by patients’ questioning, to determine whether they noticed an increase in their heart rate after anesthetic solution deposition. Objective heart rate was assessed by measuring the radial pulse of each patient and grouped into the following 3 time periods:

Period 1: Two minutes prior to solution deposition for 15 s.

Period 2: One minute during solution deposition for 15 s.

Period 3: Three minutes after solution deposition for 15 s.

Statistical analysis

The data of number of patients with success and failure of intraosseous anesthesia, of discomfort rating of each patient during the whole procedure and of pulse rate (heart rate) of each patient during 2 min before, 1 min during and 3 min after intraosseous anesthesia were collected. The data was statistically analyzed. ‘Z test’ for single proportion was used for anesthetic success and failure and confidence interval was calculated by the Wilson method.[19] The ‘Chi-square test’ was used to test the significance of difference between observed and expected proportion for discomfort ratings of patients during X-tip perforation and solution deposition. Mean objective increase in pulse rate (heart rate) between 2 min before, during and 3 min after intraosseous anesthesia were calculated by the “Paired t-test.” The “Paired t-test” was used to analyze the significance of mean objective increase in heart rate between 2 min before, during and 3 min after intraosseous anesthesia, and P value < 0.05 was set as significant.

RESULTS

Among 30 patients, two patients were excluded because of backflow of anesthetic solution into the oral cavity, which were considered as technical failures. Teeth included were one mandibular second premolar, 25 mandibular first molars and four mandibular second molars. In three subjects, intraosseous injection was given mesial to the involved tooth because of reduced mouth opening in those patients.

Anesthetic success and failure of the X-tip technique is presented in Table 1. Discomfort ratings for patients during X-tip perforation and solution deposition is shown in Table 2. Subjective and mean objective increase in heart rate (pulse rate) is shown in Table 3.

Table 1

Patients who achieved anesthetic success and failure with the X-tip technique

Table 2

Discomfort ratings for patients during X-Tip perforation and solution deposition

Table 3

Subjective and mean objective increase in heart rate (pulse rate)

DISCUSSION

Supplemental injections are essential in patients with irreversible pulpitis when pulpal anesthesia from IAN block is inadequate and the pain is too severe for the endodontist to proceed. Various factors associated with anesthetic failure for conventional IAN block include accessory innervations, accuracy of needle placement, anesthetic solution migration along the path of least resistance, tetrodotoxin-resistant class of sodium channels, which have been shown to be resistant to the action of local anesthetics, anxiety and psychological factors.[17] Another explanation for failure is that nerves arising from inflamed tissue have altered resting potentials and decreased excitability thresholds.[1017] Patients in pain are often apprehensive, which lowers the pain threshold. Therefore, practitioners should consider supplemental techniques, such as intraosseous[1314] or periodontal-ligament injections[1220] when an IAN block fails to provide pulpal anesthesia for patients with irreversible pulpitis.

In a study by Nusstein et al., the success of supplemental X-tip intraosseous injection in achieving pulpal anesthesia in patients with irreversible pulpitis was 82% and the failure rate was 18%.[17] In the current study, the success rate was 93% (26/28). We observed backflow in two subjects into the oral cavity during solution deposition in 30 injections. Except in X-tip perforation, these two subjects were excluded from the study because of technical failure not due to anesthetic failure.

In the current study, 7% (2/28) of the patients experienced anesthetic failure. The lack of 100% success with this technique may be related to constricted cancellous spaces that limited the distribution of the anesthetic solution around the apices of the teeth. Selecting an intraosseous injection site immediately distal to the tooth would provide better pulpal anesthesia.[21] Therefore, in our study, selection of mesial site for anesthesia in these two cases may be another reason for the failure. For X-tip perforation, in our study, 96.66% (29/30) of patients reported none or mild pain, whereas 3.34% (1/30) patients reported moderate pain; no severe pain was reported by any of the patients.

Pain during solution deposition usually occurred at the initial phase of solution deposition, and lasted for a few seconds only. Various authors have reported a transient increase in heart rate (46-90% of the time) with the Stabident intraosseous injection of epinephrine and levonordefrin containing solutions.[31422-24] Mean objective increase in pulse rate (heart rate) was recorded in 96% (27/28) of the patients. Only in 4% (1/28) of the patients was there no increase in the heart rate. Mean objective increase in pulse rate (heart rate) during solution deposition from baseline was 18.93 + 10 beats/min and mean increase in heart rate 3 min after solution deposition from baseline was 9.21 + 6 beats/min. Guglielmo et al. reported that the supplemental Stabident intraosseous injection of 1.8 ml of 2% lidocaine with 1:100,000 epinephrine or 2% mepivacaine with 1:20,000 levonordefrin resulted in a mean increase in heart rate of 23-24 beats/min (measured with a pulse oximeter) in 80% of the subjects.[3]

Our study recorded a greater percentage of patients (96%) with an increase in heart rate. The reason for this might be due to an increase in the concentration of adrenaline (1:80,000) in local anesthetic solution used for primary as well as intraosseous anesthesia. In general, studies showed that the heart rate returned to baseline readings within 4 min in most patients. Therefore, injection of anesthetic solutions containing vasoconstrictors, using the X-tip system, would result in a transient increase in the heart rate. The onset of anesthesia was immediate for those patients receiving successful X-tip injections, i.e., endodontic access was begun as soon as the rubber dam was placed and the patients experienced none or mild pain. Previous studies of the intraosseous Stabident system have also shown immediate onset.[141522-24] Intraosseous injections provide a shorter duration of anesthesia than with mandibular block or infiltration. However, pulpal anesthesia has a duration of less than 60 min with vasoconstrictor and approximately 15-30 min without vasoconstrictor.[25]

The risks factors associated with intraosseous injections include separation of the perforator needle from the plastic shank and that localized infection can occur at the site of perforation and may require use of oral antibiotics. The most significant concern with this route is increased heart rate that occurs when using epinephrine and levonordefrin containing solutions.[25]

None of the X-tip perforators broke, i.e., there was no metal fracture. Removal of guide sleeve was generally easy. The X-tip manual recommends using an X-tip system in attached gingiva where the Stabident system is used.[19] Future studies may determine if the location in the oral cavity affects the difficulty of guide-sleeve removal.

CONCLUSIONS

From the results of this study, it can be concluded that there was a high success rate of X-tip intraosseous injection in achieving profound pulpal anesthesia for successful endodontic treatment in patients with irreversible pulpitis.