hypersensitivity is not related to any concomitant dental pathology. 4-6 The prevalence of such condition is slightly higher in females between 20 and 40 years old (8-57%). 7-11 The relationship between the permeability of dentinal tubules and painful symptoms was described by Brännström with the dentinal hydrodynamic theory. 12 Any of the above mentioned stimuli may cause a disturbance of the dentinal tubular fluid and thereby stimulate the baroreceptors of the pulpal nerves responsive to pain. 13-15 The permeability of the outer dentinal tubules is due to the mechanical (abrasion) or chemical (erosion) removal of the intratubular smear layer. 16 Dentinal hypersensitivity is one of the disadvantages of dental bleaching most frequently reported by patients after the use of peroxides. According to several studies, the more concentrated the peroxides, the higher the incidence of dentinal hypersensitivity. 17-20 Different materials and techniques were proposed to treat Effects of the combined action of a desensitizing gel and toothpaste on dentin hypersensitivity due to dental bleaching Massimo Amato, 1 Paola Carratù, 2 Giuseppe Pantaleo, 3 Bruna Borelli, 4 Roberto Sorrentino 5 Scientific Introduction Dentinal hypersensitivity, presenting as a brief and acute painful sensation, represents an excessive reaction to non- noxious tactile, chemical, thermal, electrical, osmotic and evaporative (dehydration) stimuli. 1-3 Moreover, dentinal 62 INTERNATIONAL DENTISTRY – AFRICAN EDITION VOL. 2, NO. 6 1 Massimo Amato, MD, DDS, Department of Medicine and Surgery, University of Salerno, Salerno, Italy 2 Paola Carratù, MD, DDS, Department of Oral and Maxillofacial Sciences, University “Federico II” of Naples, Naples, Italy 3 Giuseppe Pantaleo, DDS, Department of Oral and Maxillofacial Sciences, University “Federico II” of Naples, Naples, Italy 4 Bruna Borelli, DDS, PhD Student, Department of Oral and Maxillofacial Sciences, University “Federico II” of Naples, Naples, Italy 5 DDS, MSc, PhD, Department of Oral and Maxillofacial Sciences, University “Federico II” of Naples, Naples, Italy Corresponding Author Dr. Roberto Sorrentino Via Generale Giovanni De Bonis, 75 - 80123 Napoli (Italy) Tel: 0039.3453599075 • Email: errestino@libero.it Abstract Objectives: The present study is aimed at evaluating the effectiveness of a fluoride- and potassium nitrate-containing gel and toothpaste in reducing dentinal hypersensitivity due to dental bleaching. Materials and methods: Specific inclusion and exclusion criteria were used to recruit patients for the study. They were randomly allocated to a test or a placebo control group. Patients underwent a treatment of home dental bleaching with 10% carbamide peroxide. Dental shades were evaluated in a standardized environment and dentinal hypersensitivity was valuated by means of evaporation stimuli. A nominal scale was used to score the painful reaction. The patients were recalled 8, 15 and 28 days after the baseline for both shade and sensitivity assessment. Statistical analysis was performed using the Student’s T-test. Results: The patients recall rate was 96.9%. The statistical analysis demonstrated a significant reduction of the painful symptoms in the experimental group (p=0.031) while no statistically significant differences were evidenced in the control group at any follow-up recall (p>0.05). Discussion: The tested agents proved to be safe and effective in the short term. Neither pigmentations nor interferences with the bleaching action of peroxides due to the desensitizing agents were observed. The compliance of the patients to the proposed protocol as well as the motivation to maintain good oral hygiene were paramount in the achievement of the reported results. Conclusions: The use of a desensitizing gel and toothpaste containing fluoride and potassium nitrate was effective in reducing dentinal hypersensitivity due to dental bleaching and did not interfere with the bleaching action of peroxides. Clinical significance: Desensitizing gels and toothpastes containing fluoride and potassium nitrate can be considered safe and effective in the control of tooth sensitivity after dental bleaching. Short title: Treatment of dentin hypersensitivity due to dental bleaching Key words: Tooth sensitivity, dental bleaching, toothpaste, carbamide peroxide