A summary of: Gao, X., & Meng, K. (2020). Comparison of articaine, lidocaine and mepivacaine for buccal infiltration after inferior alveolar nerve block in mandibular posterior teeth with irreversible pulpitis. British Dental Journal, 228(8), 605-608. doi: 10.1038/s41415-020-1434-9
Research was undertaken to compare the anaesthetic efficacy of 4% articaine, 2% lidocaine and 2% mepivacaine, all in combination with 1:100,000 adrenaline for buccal infiltration (BI), following lidocaine IANB in mandibular posterior teeth with irreversible pulpitis.
Irreversible pulpitis involves spontaneous and impulsive pain so the fear of pain during and after treatment of IP can induce dental anxiety in some patients leading to delay or avoidance of treatment. More than 50% of Americans avoided dental treatment because of this.
Effective pain control is a key perquisite of endodontic treatment with the IANB being one of the most commonly employed techniques for achieving pulpal anaesthesia during treatment of mandibular posterior teeth. However, its failure rate ranges from 43% – 83% owing to anatomical variations and accessory innervations so supplementary injections are essential such as the BI supplementary technique.
A prospective, randomised clinical trial was conducted on adult patients with a positive IP diagnosis and no reported history of difficult anaesthesia, significant medical conditions, hypersensitivity of substances used in the study and a strict exclusion criterion to ensure validity of the results.
Patients with irreversible pulpitis in mandibular posterior teeth and unsuccessful IANB were randomly assigned to three groups:
- Articaine group (n = 52)
- Lidocaine group (n = 52)
- Mepivacaine group (n = 52)
They were instructed to rate the pain experienced at four phases on a Heft – Parker visual analogue scale (VAS):
- Before the injection
- After IANB
- After BI
- During endodontic access
After the IANB was administered, its success was assessed using lip numbness and cold testing the teeth; patients with negative cold response and no/mild pain were regarded as successful IANB and excluded. The unsuccessful IANBs were randomly assigned a supplemental BI in either articaine, mepivacaine or lidocaine.
To interpret the data, the VAS was divided into the following four categories: no pain corresponded to 0 mm on the scale; mild pain was defined as greater than 0 and ≤54 mm; moderate pain was defined as greater than 54 and less than 114 mm; and severe pain was defined as 114 mm or more. Success was defined as the ability to access and instrument the tooth with no pain or mild pain equal to a VAS rating ≤54 mm after BI.
Multivariate logistic regression analysis showed that articaine was associated with a higher success rate compared with lidocaine (OR = 3.89, 95% CI: 1.35-11.27; P = 0.02) and mepivacaine (OR = 3.67, 95% CI: 1.24-9.75; P = 0.01), after controlling for age, gender and initial pain. VAS ratings were significantly lower in the articaine group compared with those in the lidocaine group and mepivacaine group after BI and during endodontic access (P <0.01).
Articaine is a unique amide LA with its thiophene ring, potentially being the reason for its higher success rate. It allows greater lipid solubility and potency so a greater portion of the administered dose can enter neurons.
Sarish Ikram, 4th year BDS