Evaluation of the Effectiveness on Dentin Hypersensitivity of Sodium Fluoride and a New Desensitizing Agent, Used Alone or in Combination with a Diode Laser: A Clinical Study  
[PERSON]  
1 Multidisciplinary Department of Medical-Surgical and Dental Specialities, University of Study of Campania, \"[PERSON]\", Via De Creechio 6, 83138 Naples, Italy; [EMAIL_ADDRESS] (L.F.); [EMAIL_ADDRESS] (R.F.)  
[PERSON]  
1 Multidisciplinary Department of Medical-Surgical and Dental Specialities, University of Study of Campania, \"[PERSON]\", Via De Creechio 6, 83138 Naples, Italy; [EMAIL_ADDRESS] (L.F.); [EMAIL_ADDRESS] (R.F.)  
[PERSON]  
1 Multidisciplinary Department of Medical-Surgical and Dental Specialities, University of Study of Campania, \"[PERSON]\", Via De Creechio 6, 83138 Naples, Italy; [EMAIL_ADDRESS] (L.F.); [EMAIL_ADDRESS] (R.F.)  
[PERSON]  
1 Multidisciplinary Department of Medical-Surgical and Dental Specialities, University of Study of Campania, \"[PERSON]\", Via De Creechio 6, 83138 Naples, Italy; [EMAIL_ADDRESS] (L.F.); [EMAIL_ADDRESS] (R.F.)  
[PERSON]  
2 Department of Surgical Sciences, University of Turin, 10124 Torino, Italy; [EMAIL_ADDRESS] (Correspondence:[EMAIL_ADDRESS] (F.F.); [EMAIL_ADDRESS] (L.N.); [EMAIL_ADDRESS] (V.G.); Tel.: +39-3287522211 (F.F.); +39-3339233377 (L.N.); +39-349085928 (V.G.)  
R. F. F.  
72-98% [4]. Several theories have been proposed to explain the mechanisms of DH. The most widely accepted theory was proposed by [PERSON] and [PERSON] in 1972 and is known by the name of \"hydrodynamic theory\". According to this theory, pain is caused by moving fluid within the dentine tubules [5,6]. The ability to close the dentine tubules, reducing the movement of fluid in them, allows blocking the painful sensation in the pulp and is considered the ideal treatment of DH [7]. In the wake of the hydrodynamic theory, several methods have been used to occlude open dentine tubules, such as the application of sodium fluorides (NaF) in a gel, thus causing tubule obstruction by calcium fluoride precipitation in the tubules, the use of other desensitizing molecules causing a mechanical blockage of the dentinal tubules through the precipitation of proteins in the dentinal fluid, as well as the use of a casein phosphopeptide varnish and of silver nitrate [8, 9, 10]. Other desensitizing agents that act with different mechanisms to control DH pain have been studied, such as a potassium nitrate-based gel that reduces pain by acting on nerve conduction [11,12]. Furthermore, to improve and ensure a longer duration of the pain relief from DH, treatments with desensitizer agents that act with different mechanisms, such as the desensitizing VivaSens(r), were proposed [13, 14, 15].  
The study of [PERSON] et al. confirmed the effectiveness of a mouthwash containing 3% potassium nitrate in causing a rapid relief of pain from DH, but the mouthwash did not provide statistically significant improvements on DH compared with use of fluoride toothpaste alone [16].  
[PERSON] et al. evaluated the effectiveness of three desensitizing agents, i.e., Admira Protect, VivaSens, and Neo Active Apatite, in dentinal tubule occlusion and the duration of their action and found that Admira Protect was the most effective [17]. In recent decades, the behavior and the effectiveness of some desensitizing agents,alone or in combination with lasers, on the relief of pain caused by DH have been studied. In the literature there are many studies conducted with different types of lasers, using different wavelengths and application times, revealing the effectiveness of this treatment, immediately after its application as well as after several months from the first treatment. Specifically, no comparison has been made between new desensitizing products based on a double-action system and the diode laser [18, 19, 20, 21].  
The aim of this research was to verify and compare the effectiveness of two topical agents on pain associated with DH, sodium fluoride (NaF) and VivaSens(r), used alone or in association with a diode laser.