Clinical Trial Designs for the Testing of OTC Products for Dentine Hypersensitivity-A Systematic Review

Aim: The aim of the present study was to review the papers in the published literature and to compare the clinical trial methodology used in these studies to evaluate the products for Dentine Hypersensitivity (DH) based on the previously recommended guidelines of Holland, et al. (1997). Material and Methods: A systematic search was conducted on PubMed and Embase for double blind randomized placebo-controlled clinical studies conducted over ≥6 weeks assessing the efficacy of OTC products for the treatment of DH in otherwise healthy adult subjects with reported and diagnosed DH. Results: A total of 35 studies were included in this review from an initial search of 882 titles. All the included studies complied with the guidelines in terms of study design, duration, subject selection, adequate control(s) and subject instructions. 91% of studies used a sample size of ≥ 25 per arm. Most studies (91%) complied with the minimum required number of teeth to be test ed except in two studies. All the studies used an objective assessment however only two studies (22.8%) included a subjective evaluation to an everyday stimulus when evaluating DH. Only two studies included assessment of the impact of DH treatment on the participants’ Quality of Life (QoL). Most studies did not include a recommended specific run in/wash period (10 studies [28.5%]) or a follow up period following the cessation of the study (2 studies [5.7%]). All studies reported the reduction of DH as a percentage reduction from baseline values. None of the studies reported a total relief of pain irrespective of the in- tervention(s) evaluated although there were mean reductions in both test and control groups. Conclusions: All of the included studies reported a significant statistical reduction of pain in both the test and control groups, although none of the studies reported the complete absence of the pain response following any of the interventions at the end of the studies. Overall, most studies complied with the recommendations from the Holland, et al. guidelines however, there is still a need to include both a run in/wash out and follow up periods in future studies. Furthermore, it may be recommended to include a subjective evaluation of the treatment outcome to overall sensitivity from day to day activities as well as the effect on the QoL (person-centered approach) in future studies. None of the included studies reported the complete absence of the pain response following any of the interventions at the end of the studies