A comparative evaluation of anesthetic efficacy of articaine 4% and lidocaine 2% with anterior middle superior alveolar nerve block and infraorbital nerve block: An in vivo study.

BACKGROUND: The ideal maxillary injection should produce a rapid onset of profound pulpal anesthesia for multiple teeth from a single needle penetration. The main objective is to compare the efficacy of articaine 4% and lidocaine 2% and to compare anterior middle superior alveolar nerve block (AMSANB) and infraorbital nerve block (IONB) for anesthesia of maxillary teeth.
MATERIALS AND METHODS: Forty patients undergoing root canal treatment of maxillary anteriors and premolars were included and randomly divided into four groups of ten each. Group I: patients receiving AMSANB with articaine, Group II: Patients receiving IONB with articaine, Group III: Patients receiving AMSANB with lidocaine, Group IV: Patients receiving IONB with lidocaine. The scores of onset of anesthesia and pain perception were statistically analyzed.
RESULTS: Onset of action was fastest for articaine with AMSANB and slowest for lidocaine with IONB by Tukey's test. A significant change was observed in the electrical pulp test readings at onset and at 30 min by paired t-test. All patients experienced mild pain during the procedure recorded by visual analog scale.
CONCLUSION: Articaine 4% proved to be more efficacious than lidocaine 2%, and AMSANB was more advantageous than IONB in securing anesthesia of maxillary anteriors and premolars.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Pain is one of the most commonly experienced symptoms in dentistry and is a major concern to the dentist. Pain, in many instances, is considered as a caution signal. In practice of dentistry, pain is no more a warning signal, instead it is an evil to be conquered. One of the most important aspects of the practice of dentistry is the control or elimination of pain.

The most essential skill of all dental practitioners is the ability to provide safe and effective local anesthesia.[1] Fear and anxiety associated with endodontic treatment are reduced with effective pain management.[2] A revolutionary advancement of the late 1800s was the discovery of local anesthetics that facilitated pain prevention without the loss of consciousness. Lidocaine hydrochloride is the most commonly used anesthetic agent since its clinical availability in 1948. It is labeled as “gold standard” due to its efficacy, low allergenicity, and minimal toxicity.[3] Articaine is a widely used anesthetic agent in developed countries. It has a more profound level of anesthesia and greater ability to diffuse through tissues.[4]

Anesthesia of maxillary anteriors and premolars can be achieved by infraorbital nerve block (IONB) or anterior superior alveolar (ASA) which involves deposition of the anesthetic solution at the infraorbital foramen.[56] Anatomic variations in anterior maxilla are very common, which reduces the success of anesthesia. Multiple needle penetrations will be necessary to ensure an adequate volume of anesthetic solution which is deposited at the target site. The ideal maxillary injection should produce a rapid onset of profound pulpal anesthesia for multiple teeth from a single needle penetration. The literature does not explain a single injection site that would produce pulpal anesthesia to the majority of the maxillary teeth without collateral anesthesia of the face, lip, and muscles of expression.[7]

Alternate nerve blocks are anterior middle superior alveolar nerve block (AMSANB) and palatal approach to the ASA.[8] Friedman and Hochman suggested that administration of anesthetic solution midpalatally using slow, constant pressure would access to the ASA and middle superior alveolar nerve and their plexuses. This technique induces anesthesia from the incisor to the premolar and possibly to the mesiobuccal root of the first molar.

Thus, the aim of this study is to comparatively evaluate anesthetic efficacy of articaine 4% and lidocaine 2% with AMSANB and IONB for anesthesia of maxillary anteriors and premolars.

MATERIALS AND METHODS

The study was conducted in the Department of Conservative Dentistry and Endodontics, and institutional ethical clearance was obtained. The patients were explained about the procedure, and informed consent was obtained. Patients were administered 0.1 ml of the anesthetic agent (intradermal allergy test) on the dorsal part of their arms and were observed for hypersensitivity reactions. The patients (participants) were not disclosed about the anesthetic agent as well as the technique.

Patients undergoing root canal treatment of maxillary anteriors and premolars were included. Before administration of nerve blocks, the pulpal response was tested with the electric pulp tester (Digitest, Parkell, Inc., USA) and the value was recorded for all the cases. The nerve blocks were administered by a single operator.

Inclusion criteria

Patients aged between 18 and 65 years in good health (ASA I or II)

Patients reporting with spontaneous pain ranging from 7 to 9 on numerical reading scale

Patients who granted informed consent.

Exclusion criteria

Known case of allergy to local anesthetic agents

History of significant medical problem (ASA III or greater)

Patients who had taken central nervous system depressants including alcohol or any analgesic medication within the last 48 h

Pregnancy

Inability to give informed consent

The patients were randomly divided into four groups of ten each:

Group I: Patients receiving AMSANB with articaine HCl 4% with 1:100,000 adrenaline (Septodont, France)

Group II: Patients receiving IONB with articaine HCl 4% with 1:100,000 adrenaline

Group III: Patients receiving AMSANB with lidocaine HCl 2% with 1:80,000 adrenaline (Indoco Remedies, India)

Group IV: Patients receiving IONB with lidocaine HCl 2% with 1:80,000 adrenaline.

Procedure

Patients received 0.9–1.2 ml of anesthetic agent for classic IONB using conventional Luer lock 2 ml syringe with 26-gauge, 1½ inch needle using aseptic measures, and sterile techniques. For AMSANB, 0.6–1.4 ml of the anesthetic agent was deposited using slow, constant pressure in the palatal mucosa. The nerve blocks given with articaine 4% were administered with standard cartridges (1.7 ml) and an aspirating syringe equipped with 27-gauge, 1½ inch needle.

The following data were collected for interpretation of results:

Onset of anesthesia: It was assessed from the time lapse between the end of the nerve block and onset of symptoms of subjective anesthesia (feeling of heaviness at the site of injection). A standard digital stop clock was used. It was calculated in seconds

Extent of pulpal anesthesia: The response to electrical pulp tester was obtained at three intervals - before the administration of nerve block, after the onset of anesthesia, and 30 min after anesthesia. The numerical readings were recorded

Pain assessment: The pain on injection was rated by VAS. Patients were showed the scale and were asked to mark the pain rating. The corresponding pain score on the numerical scale was recorded.

The readings were statistically analyzed using SPSS software version 20.0 (IBM Corp, Armonk, NY, USA) by two-way analysis of variance (ANOVA) test, Tukey's multiple post hoc procedures, paired t–test, and Mann–Whitney U-tests.

RESULTS AND OBSERVATIONS

The study included forty patients. All the patients responded well with no history of any adverse event. A significant difference was observed in the onset of anesthetic action between articaine 4% and lidocaine 2% by two-way ANOVA test (P < 0.05) [Table 1 and Graph 1]. The onset of action was the fastest for articaine 4% with AMSANB (Group I) and the slowest for lidocaine 2% with IONB (Group IV) by Tukey's multiple post hoc procedures (P < 0.05) [Table 2].

Table 1

Comparison of two main (lidocaine 2% with adrenaline and articaine 4% with adrenaline) and two subgroups (infraorbital nerve block and alveolar nerve block) with onset of anesthesia (s) by two-way ANOVA

Graph 1

Comparison of two main (lidocaine 2% with adrenaline and articaine 4% with adrenaline) and two subgroups (infraorbital nerve block and anterior middle superior alveolar nerve block) with onset of anesthesia (in seconds)

Table 2

Pair-wise comparison of two main (lidocaine 2% with adrenaline and articaine 4% with adrenaline) and two subgroups (infraorbital nerve block and alveolar nerve block) with onset of anesthesia (mm) by Tukey's multiple post hoc procedures

The mean electric pulp testing (EPT) readings before the nerve blocks were 13 for articaine with AMSANB, 12.3 for articaine 4% with IONB, 13.25 for lidocaine 2% with AMSANB, and 16 for lidocaine 2% with IONB, respectively. No response was observed on maximum stimulation (reading = 64) at the time of onset and after 30 min among all the groups. A significant change was observed in the EPT readings before the injection and at the onset of anesthesia by paired t-test (P < 0.05) in all the groups [Graph 2].

Comparison of electric pulp testing scores preoperative, at onset and after 30 min among four groups

The mean pain scores for Group I, Group II, Group III, and Group IV were 0.60, 0.22, 0.75, and 0.82, respectively. Pain perception was least (0.22) for IONB with articaine 4%. In this study, the maximum pain was felt for IONB with lidocaine 2% (0.82). The mean rating on the scale was <1 by Mann–Whitney U-test. The pain experienced was mild as expressed by patients on VAS which corresponded with the scores of numerical rating scale (NRS) [Graph 3].

Comparison of two main (lidocaine 2% with adrenaline and articaine 4% with adrenaline) and two subgroups (infraorbital nerve block and anterior middle superior alveolar nerve block) with VAS scores

DISCUSSION

Local anesthesia remains the backbone of pain control in dentistry. Local anesthetics are the effective drugs available for the prevention and the management of pain. During endodontic treatment, effective pain control is necessary for patient comfort and to reduce operator stress.

Local anesthetic agents represent the dentists’ primary means of pain control.[9] Lidocaine, also known as lignocaine, is an amide anesthetic that has been described as the most commonly used local anesthetic for dental use. Lidocaine provides pulpal anesthesia for approximately 1 h and soft tissue anesthesia for 3–5 h.[10]

Articaine was originally synthesized in 1969. Articaine, the second most commonly used dental anesthetic, was first introduced to the European market in 1976 and entered the US market in 2000.[11] Pulpal anesthesia duration is approximately 1 h. The soft tissue anesthesia is approximately 2.25 h for maxillary infiltrations.

According to Malamed, articaine was well tolerated in clinical trials and had the toxicity profile comparable to that of lidocaine. Dentistry's clinical experience with articaine with epinephrine formulations through the years supports the assertion that the risk of systemic toxicity with articaine is low. Articaine 4% with epinephrine 1:100,000 is a safe local anesthetic for use in clinical dentistry and can be effectively used in both adults and children.[10]

Lidocaine 2% is commonly used by most dentists with the conventional needle technique, and the study intended to check the efficacy in that technique only and not by using cartridges unlike with articaine 4%. The administration of local anesthetic with the cartridge is technique-sensitive and needs a learning curve. The present study showed that articaine 4% had a faster onset as compared to lidocaine 2%. Articaine is 1.5 times potent to that of lidocaine.[6] Articaine is unique among amide local anesthetics, in that it contains a thiopentone group instead of the benzene ring found in lidocaine and other amide local anesthetics.[11] The thiopentone ring contains a methyl ester side linkage that contributes to articaine's rapid conversion to articainic acid, its primary metabolite. Thiopentone ring increases liposolubility, higher the potency and diffusion through the epineurium.[1213]

Alam et al. reported more profound level of anesthesia and a greater ability to diffuse through tissues.[4] Various other authors have speculated on a few mechanisms for increased efficacy of articaine. Borchard and Drouin found that a lower concentration of articaine was sufficient to block an action potential when compared with other amide anesthetics (benzene derivatives). Potocnik et al. found out in a study of rat sensory nerve conduction that 4% articaine was superior to 2% lidocaine in blocking nerve conduction.[14] Brandt et al. reported that articaine was 3.81 times more likely to achieve anesthetic success when infiltration mode of administration is used.[15]

In the present study, AMSANB with 4% articaine had a faster onset as compared to IONB with 2% lidocaine. The AMSANB is more efficacious than IONB which offers various advantages. It improves patient comfort through the elimination of repetitive transmucosal punctures which reduces the total amount of delivered vasoconstrictor and proves useful for cardiovascular compromised patients requiring maxillary anesthesia. It gives an outstanding hemostatic control, avoidance of undesirable collateral anesthesia, and a reduced number of cumulative injections.[416171819]

The EPT readings taken at three intervals proved to be a clinically efficient tool for assessing the technique sensitivity of the nerve blocks.[20] The EPT readings of the present study confirmed that the electric pulp tester served as a valuable aid in determining clinical analgesia. The pain rating on the VAS as interpreted by NRS was found to be of mild range. It suggested that patients experienced mild pain during administration of both the nerve blocks. Patients were comfortable during the procedure done. The EPT readings and the pain scores were clinically significant to confirm that the nerve blocks provided definite pulpal anesthesia with least amount of soft tissue anesthesia.

In the present study, traditional syringes were used and patients experienced mild pain only during the palatal injections. The AMSA injection using the Wand resulted in similar pain ratings for needle insertion but statistically lower pain ratings on anesthetic solution deposition.[21] According to Fukayama et al.[17] and Saloum et al., the Wand provided less painful injections compared to the traditional syringe. The mean pain ratings were mild for both injections.[22] Goodell GG. concluded that a conventional atraumatic syringe injection technique was superior to a controlled injection pressure system in pain perception and pain tolerance and in reducing postinjection dental anxiety.[23] Another important factor is cost effectiveness of using traditional syringes and Wand, wherein cost factor was definitely decreased with traditional syringe making it an affordable technique.[24]

This study is unique in that the two important and clinically useful anesthetic agents were compared and found to be clinically significant. IONB and AMSANB were efficient to provide pulpal anesthesia for maxillary anterior teeth and premolars.

CONCLUSION

This study shows that statistically significant differences are observed between articaine and lidocaine. Articaine has a faster onset and provides clinically effective anesthesia. AMSANB offers numerous advantages and is an effective alternate to the classic IONB. Within the limitations of the study, articaine 4% with AMSANB can be effectively used for anesthesia of maxillary anteriors and premolars.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.