The efficacy of a novel zinc-containing desensitizer CAREDYNE Shield on dentin hypersensitivity: study protocol for a pilot randomized controlled trial

Background: Dentin hypersensitivity (DH) is a condition characterized by short and sharp pain which will arise in response to tactile, chemical, thermal, evaporative or osmotic stimuli. The painful symptoms cause discomfort to the patients and decrease their quality of life. Recently, a novel zinc-containing desensitizer CAREDYNE Shield is developed. It is a new type of desensitizer which acts as a desensitizer by inducing chemical occlusion of dentinal tubules, and releases zinc ion for root caries prevention. However, the clinical effectiveness of CAREDYNE Shield on DH is still unclear. Therefore, the aim of this study is to evaluate the effectiveness of CAREDYNE Shield on DH by comparing with that of another desensitizer Nanoseal commonly used in Japan.Methods/Design: This study protocol is a two-arm parallel pilot randomized controlled trial. Forty DH patients will be randomly allocated into 2 groups. Participants in the intervention group will be treated with CAREDYNE Shield; participants in the control group will be treated with Nanoseal. Primary outcome is the reduction of pain intensity in response to air stimuli measured with 5-points verbal response scale from baseline to 4 weeks after the intervention and Fisher's exact test will be used for analysis.Discussion: CAREDYNE Shield can be casually applied to subgingival areas and proximal surfaces because it reacts with only tooth substance. Moreover, zinc is reported to reduce the demineralization of enamel and dentin and inhibit biofilm formation, plaque growth and dentin collagen degradation. Therefore, CAREDYNE Shield may be expected to become a novel useful desensitizer which act not only as a desensitizer but also as a root caries inhibitor.