Blinding The patients and the examiner who evaluated the effectiveness (other than the operator), were not aware of the type of treatment corresponded to each tooth. Application procedure The desensitizing agents were applied third by a trained and experienced operator, on days 1st, 7th, 14th and 21st as follows: Removal of debris and calculus, if any, around the affected teeth using hand scalers. Isolation of the teeth with cotton rolls. The tooth surfaces were dried with a cotton pellet and compressed air by using an air syringe for 15 s. Propolis extract and a placebo were applied directly on the DH site using a truncated needle and let dried for 60 s. Recaldent? (CPP-ACP) was applied to the sensitive lesions as recommended by the manufacturer. Care was taken to ensure none of the product touched other zones of the oral mucosa.

Excess was removed by using cotton pellets. The patients were instructed not to rinse, eat or drink for 30 min after the treatment and avoid using any other professionally or self-applied desensitizing agent in the course of the investigation. Effectiveness evaluation The effectiveness evaluation was carried out by a calibrated examiner. The calibration of the examiner was carried out at the department of Public Health Dentistry in Peoples Dental Academy, Bhopal. Examiner calibration The examiner was trained and calibrated to record the sensitivity patterns on a group of 10 patients who were diagnosed with DH. The intra examiner weighted kappa value was calculated using the baseline values for hypersensitivity and reexamining all the patients and was determined to be 0.

73. Each tooth received two stimuli:[22] Clinical probing (tactile stimulus) and Air blast (thermal evaporative stimulus). The probe stimulus was applied under slight manual pressure in the mesiodistal direction on the cervical area of the tooth. The test was repeated 3 times before recording the final score. Air blast was applied with an air syringe for 1-2 s at the distance of 1 cm of the tooth surface to avoid desiccating the dentin surface while the adjacent teeth were protected by the examiner finger.[23] The degree of hypersensitivity reported by the participant with each stimulus was determined according to the verbal rating scale (VRS)[22] from 0 to 3, in which: 0 = No discomfort, 1 = Minimum discomfort, 2 = Mild discomfort, and 3 = Intense discomfort.

The values were collected before the intervention (baseline values) and after each application, on days Batimastat 1st, 7th, 14th, and 21st respectively. The spilt mouth technique was used to obtain the standardized response from each patient for all three treatment groups. Evaluation of success/failure The final criteria for evaluation were[24] Rapid reduction in DH (after 1st and 2nd application), Overall reduction in DH (after 4th application) and No reduction in DH. Safety evaluation Two safety variables were evaluated: irritation and burning sensation in the mucosa next to the treatment site.