Clinical Efficacy in Relieving Dentin Hypersensitivity of Nanohydroxyapatite-Containing Toothpastes and Cream

This is a double-blind, randomized, controlled, parallel group, outpatient clinical trial, involving a total of 270 patients diagnosed with dentin hypersensitivity, who will be randomly assigned to nine treatment groups of 30 patients each. Males or females of age 18 to 80 years will be enrolled. The nine groups will be randomly assigned to use one of the nine test products: (1) toothpaste containing nano-HAP (high concentration); (2) toothpaste containing nano-HAP (low concentration); (3) toothpaste containing nano-HAP and potassium nitrate (KNO3); (4) toothpaste containing NovaMin; (5) standard fluoride toothpaste with 1500 ppm MFP; (6) toothpaste containing nano-HAP (medium concentration); (7) placebo toothpaste; (8) cream containing nano-HAP; (9) placebo cream. Subjects will be instructed to use the study toothpaste as their sole oral hygiene product for the 8 weeks treatment duration while the cream will be applied with a retainer tray for 5 minutes before bed at night. For those using toothpastes, subjects will be instructed to brush their teeth twice daily for 2 minutes, morning and last thing before bed, applying on each occasion a one-inch strip of their assigned toothpaste on a wetted commercially available soft-bristled toothbrush. Dentin hypersensitivity examination, which will include air blast sensitivity and cold thermal sensitivity combined with visual analog scale and Dental Pain Scale, will be conducted at baseline, 2, 4, 6, and 8 weeks. Subjects will be screened for adverse effects on every visit, and all observed adverse events will be recorded when they occur.

Inclusion criteria

• Must be between the ages of 18 and 80, inclusive
• Must be in good general health based on medical history and oral soft and hard tissue examinations
• Must be willing and able to provide informed consent
• Must be able to read and comprehend study materials
• Must have access to a phone for regular study contact
• Must be willing to use the assigned products according to instructions, and be availability for appointments.
• Must have been diagnosed of having dentin hypersensitivity by a dentist, with at least one sensitive tooth with demonstrated cervical erosion/abrasion or gingival recession
• As a final entrance criteria, the sensitive tooth must respond to:

• air sensitivity, with Schiff score >1, assessed by use of a one-second blast of air.
• thermal sensitivity, assessed with frozen cotton pellet, with a pain rating of at least moderate pain on the Dental Pain Scale (DPS) and a score between 30 and 80 mm on a 100 mm scale on the Visual Analog Scale (VAS).

Exclusion criteria

• Subjects who answer YES to any of the following questions will not be enrolled into the study:

• Any history of significant adverse effects following use of oral hygiene products such as toothpastes and mouthwashes?
• Does the subject have any physical limitations or restrictions that might preclude use of normal oral hygiene procedures (i.e., toothbrushing, mouthrinsing, etc.)?
• The sensitive tooth is associated with concomitant oral pain due to any other condition such as: soft-tissue lesions or toothache from other dental conditions like dental caries, etc?
• Has the subject ever reported allergy to drugs or chemicals used in the trial?
• The sensitive tooth is associated with a periodontal abscess as diagnosed from an X-ray or clinical examination of the tooth?
• Will the subject receive dental treatment which may affect their participation (i.e. oral prophylaxis)?
• The sensitive tooth is associated with mobility > 1?
• Did the subject participate in a dental clinical trial involving oral care products within the past 30 days?
• Is the subject pregnant, nursing or planning to become pregnant during the course of the study (self-reported)?
• Does the subject have other severe, acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with trial participation or may interfere with the interpretation of trial result and, in the judgment of the investigator, would make the subject inappropriate for entry into this trial?
• Does the subject have significant oral soft tissue pathology, based on the dentist's visual examination and at the discretion of the investigator?
• 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 dentin hypersensitivity?
• Previous professional desensitizing treatment?
• Subject use of over-the-counter desensitizing products within the previous 3 months?
• Subjects using medication which could interfere with the perception of pain?
• Eating disorders or conditions associated with vomiting?
• Systemic conditions that are etiologic or predisposing to dentinal hypersensitivity?
• Excessive dietary or environmental exposure to acids?
• The sensitive tooth was restored in the preceding 3 months?
• The sensitive tooth is an abutment tooth for fixed or removable prostheses?
• The sensitive tooth has extensive restorations or restoration extending into the test area?
• Patients below 18 years or above 80 years of age?