Trial of Nano-hydroxyapatite-Containing Toothpastes for Relief of Dentin Hypersensitivity

This study is a double-blind, randomized, placebo-and positive-controlled, stratified parallel group clinical trial. The three groups will be randomly assigned to use one of three test toothpastes having an identical base formulation but containing respectively either 0% nano-hydroxyapatite (HAP) (placebo), 15% nano-HAP or 5% KNO3 (positive control). All dental examinations for data collection will be conducted by the same Clinical Examiner.

Inclusion criteria

• Males or females between the age of 20 and 80 years, of any socio-economic status
• Diagnosed as having DHS, i.e. having at least one sensitive tooth with demonstrated cervical erosion/abrasion or gingival recession
• Showing a sensitivity response to both tactile and cold air stimulus delivered by a Yeaple probe and a one-second blast of cold air respectively
• Patients must be reliable, cooperative and of adequate intelligence to read and understand the rating scales and other study instructions
• Patients must be able to read, comprehend, and sign the informed consent form
• The teeth and sites to be tested should be on the buccal/labial surfaces of incisors, canines, premolars or molars where the affected sites are accessible
• Teeth selected for testing should have a plaque index of ≤ 2

Exclusion criteria

• The sensitive tooth is associated with concomitant oral pain due to any other condition such as soft-tissue lesions, tooth-ache ascribable to dental caries, tooth fracture, or cracked tooth syndrome, or pain due to other surgical procedures or injuries.
• The sensitive tooth is associated with a periodontal abscess as diagnosed from an X-ray or clinical examination of the tooth
• The sensitive tooth is associated with mobility >1
• The sensitive tooth is associated with gum pain from gingivitis, occlusal trauma, thermal or chemical burns
• Patients having pain from periodontal-related causes but not DHS
• Previous professional desensitizing treatment
• Patients using medication which could interfere with the perception of pain
• Medical histories marked by chronic use of anti-inflammatory agents, daily analgesics, anticonvulsants, antihistamines, antidepressants, sedatives and/or other psychotropic drugs
• Pregnancy or breastfeeding
• Allergies and idiosyncratic responses to toothpaste ingredients
• Eating disorders or conditions associated with vomiting
• Systemic conditions that are etiologic or predisposing to DHS
• Excessive dietary or environmental exposure to acids
• The sensitive tooth was restored in the preceding three months
• The sensitive tooth is an abutment tooth for fixed or removable prostheses
• The sensitive tooth has extensive restoration or restorations extending into the test area
• Patients below 20 years or above 80 years of age
• Smokers