The reported prevalence of post-operative pain after root canal treatment varies widely. Most postoperative pain dissipates fairly rapidly, with severity falling by 50% after the first day and to <10% by day 7. Given the multifactorial causes and varying perceptions by individual patients, it is not surprising that many treatment modalities have been proposed to relieve postoperative pain after root canal treatment, including

  • preoperative medication
  • postoperative medication
  • long-acting anesthetics
  • intracanal medicament
  • laser therapy
  • glide path preparation
  • rotary instrumentation
  • machine-assisted irrigant agitation
  • occlusal reduction

The theory behind occlusal reduction—the selective removal of dental hard tissue resulting in the loss of some of the anatomical features of the occlusal surface—holds that removing occlusal contacts reduces mechanical stimulation, thus decreasing pressure on a tooth with inflamed periapical tissues. While studies have touted the benefits of occlusal reduction on post-operative pain following endodontic treatment, the evidence remains scant and inconsistent. Nguyen et al from the University of Melbourne, Australia, conducted the first systematic review and meta-analysis of published studies employing occlusal reduction to manage post-operative pain after root canal treatment. The 7 studies that qualified for their systematic review were randomized clinical trials that measured post-operative pain with a visual analog scale (VAS) after ≥6 hours.

The studies showed inconsistent results, perhaps due in part to differing inclusion criteria, methodology, follow-up and outcome assessment.

Of the 7 studies, which included just under 1000 patients, 3 found that occlusal reduction effectively reduced or prevented postoperative pain after root canal treatment, while 4 found no significant effect. Only 1 study found significant pain reduction in the first 24 hours. The results suggested that occlusal reduction was an effective treatment to reduce postoperative pain in teeth with irreversible pulpitis that were tender to percussion, as well as in teeth with symptomatic apical periodontitis without remarkable radiographic changes. A meta-analysis of the 3 studies that measured postoperative pain at day 6, which included more than three-quarters of all patients in the systematic review, determined that occlusal reduction decreased postoperative pain at the 6-day follow-up. Several confounding factors could have influenced the results. Use of either preoperative analgesia or low-dose corticosteroids, both recognized treatments to reduce postoperative pain, were included in most of the studies. Instrumentation (manual or rotary) varied among the studies, as did irrigation solutions and the use of intracanal medications.


Because occlusal reduction requires the permanent removal of enamel or dentin, the practitioner must weigh any possible negative sequelae of the procedure. Nevertheless, the results of this study suggest that occlusal reduction decreases postoperative pain after root canal treatment in teeth diagnosed with irreversible pulpitis and symptomatic apical periodontitis.

Nguyen D, Nagendrababu V, Pulikkotil SJ, Rossi-Fedele G. Effect of occlusal reduction on postendodontic pain: a systematic review and meta-analysis of randomised clinical trials.  Aust Endod J 2019;doi:10.1111/aej.12380.