Quantification and analysis of pain in nonsurgical scaling and/or root planing.

Background: Three efficacy studies, comprising a database of 337 subjects, were conducted as part of the clinical evaluation of the noninjectable anesthetic gel Oraqix (AstraZeneca, Södertälje, Sweden). The authors discuss some of the challenges encountered when they interpreted the results of the clinical studies and present the results from an alternative analysis of the anesthetic efficacy.

Methods: The three multicenter studies were double-blind, randomized and placebo-controlled. Clinicians applied gel in the subjects' periodontal pockets before scaling and/or root planing, or SRP. Subjects recorded overall pain on a 100-millimeter visual analog scale, or VAS. In the studies, the evaluation of the anesthetic efficacy was based on absolute treatment difference (active-placebo). Investigators used an alternative post hoc approach to evaluate the effect expressed as a ratio (active:placebo).

Results: The studies demonstrated consistent and significant lower pain scores for the anesthetic gel versus the placebo gel, with point estimates of absolute treatment difference being 8, 4 and 10 mm. The alternative analysis verified that the estimated treatment effect in terms of a ratio was close to 50 percent in all three studies.

Conclusions: Treatment effects of the anesthetic gel relative to the placebo gel were described more appropriately by means of ratios instead of absolute differences. In this sample of 337 subjects, it was shown that pain was reduced by 50 percent when the anesthetic gel was used compared with when the placebo gel was used.

Clinical Implications: The authors found that the anesthetic periodontal gel is effective in reducing pain resulting from SRP.