Effect of Nonsteroidal Anti-Inflammatory Drug as an Oral Premedication on the Anesthetic Success of Inferior Alveolar Nerve Block in Treatment of Irreversible Pulpitis: A Systematic Review with Meta-analysis and Trial Sequential Analysis

Nagendrababu, V. et al, JOE 44:6 June 2018 pp 914-922

Successful management of pain during root canal procedures is essential for patients from both a physiologic and psychological standpoint.  Adequate anesthesia is also important for the dentist.  When the patient is comfortable their stress levels are reduced, the dentist’s stress levels are reduced, and the ability to achieve our procedural goals is increased.

The most difficult teeth to achieve adequate anesthesia are the lower molars.  Getting enough anesthetic to the correct location of the inferior alveolar nerve (IAN), bathing an adequate length of the IAN (2 cm) with anesthetic, as well as auxiliary innervation results in IAN anesthesia failure rates in the 43-83% range.  This is compounded by patient psychological makeup, their unique pain thresholds, and the patient’s expectations of how successful their pain management will be.

When the molar teeth present with the signs and symptoms of irreversible pulpitis, the anesthesia challenge is magnified.  Pulpal inflammation lowers the firing threshold of pain receptors in the pulp.  This results in many more nerve fibers being activated for any given stimulus than in histologically normal pulps.  With pulpitis cases, our anesthetic must then block more nerve fiber depolarizations to achieve adequate anesthesia.

We can counter this need for increased nerve fiber blockade by additional anesthesia protocols.  Utilizing Akinosi or Gow-Gates techniques can increase the length of the IAN bathed in anesthetic solution.  However, buccal infiltration, intra-osseous injections such as the Stabident, and/or PDL injections are often needed to achieve patient comfort.  Further, the choice of anesthetics can also affect the profundity of anesthesia.

Pulpal inflammation is mediated through the production of prostaglandins in the arachidonic acid cycle by the action of cyclooxygenase enzymes.  These prostaglandins act by increasing nociceptor sensitivity.  The more prostaglandins present, the more nerve fibers in the IAN that are recruited.  The more nerve fibers that are recruited, the more profound our anesthesia needs to be.

Oral premedication with NSAIDs, which block prostaglandin formation, has been proposed by a number of authors, as a further, supplemental method for achieving patient comfort in difficult cases.  As in a lot of the literature, however, these studies all have different inclusion parameters and protocol methodologies.

Nagendrababu et al, reviewed the available literature on pain control using NSAIDs with respect to two questions:  1) does NSAID premedication in adult patients with irreversible pulpitis increase IAN anesthetic success compared with placebo; and 2) which is the most effect dose of ibuprofen.

The authors looked at 13 studies which fit their inclusion criteria. Meta-analysis and trial sequential analysis was utilized in their systematic review of these studies.  The authors concluded that a single dose of ibuprofen of at least 400mg, given to the patient prior to anesthesia increased the success of IAN blocks in patients with irreversible pulpitis.

At an anecdotal level, I have been recommending and providing 600 mg of ibuprofen, pre-operatively, to our patients receiving endodontic intervention for almost 20 years.  My rationale, based on the literature, was that NSAIDs taken pre-operatively would help reduce post-operative pain by prostaglandin blockade.  Helping with IAN success turns out to be a bonus.

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