Aim: to investigate the clinical effectiveness over 12 weeks of three different biomaterials, nano-hydroxyapatite based, in the therapy of the dental sensitivity.

Methods: The study is designed as a randomized clinical trial comparing: 1) Cavex Bite&White ExSense, 2) Teethmate™ Desensitizer , 3) Ghimas Dentin Desensitizer. The pain experience was generated by a cold stimulus directly to a sensitive tooth surface and assessed using the Visual Analogue Scale (VAS). The response was recorded before the application of the materials (PRE-1), immediately after (POST-1), at 1-week (POST-2), 4-weeks (POST-3) and 12-week controls (POST-4).

Participants The study is designed as randomized clinical trial. The participants will be selected from the regular attenders of the Dental Clinic in the University of Sassari, Italy.

Inclusion criteria:

• patients will be considered suitable for the study if they have sensitive teeth showing abrasion, erosion, or recession with the exposure of the cervical dentine;

Exclusion criteria:

• teeth with subjective or objective evidence of carious lesions, pulpitis, restorations, premature contact, cracked enamel, active periapical infection, or which had received periodontal surgery or root-planning up to 6 months prior to the investigation will be excluded from the study
• professional desensitizing therapy during the previous 3 months, or use of desensitizing toothpaste in the last 6 weeks.
• Patients will be also excluded if they will be under significant medication that could interfere with pain perception (e.g., antidepressants, anti-inflammatory drugs, sedatives, and muscle relaxants).

Randomization Using a computer program (Excel 2010 for Mac OsX), the randomization will be carried on using an individual basis.

Clinical procedure A full medical and dental history will be taken and all the teeth will be carefully examined to confirm the diagnosis of DH. The experience of dentinal hypersensitivity and how this has affected the quality of life of the patients will be evaluated through a specific questionnaire. The nature and scope of the study will be explained and informed consent will be obtained.

A week before the experiment, patients received oral prophylaxis. Non-fluoride toothpaste, soft tooth- brush and oral hygiene instructions will be also provided in order to have standardized habits during the period of the study.

A week before the experiment, patients received oral prophylaxis. Non-fluoride toothpaste (Biorepair, Coswell), a soft toothbrush (Oral-B Sensitive Advantage, Procter & Gamble) and oral hygiene instructions were also provided. The level of sensitivity experienced by each patient was considered as independent of the position of the hypersensitive tooth in the oral cavity. The pain experience was assessed by a Visual Analogue Scale (VAS) using the methodology described in our previous study. The pain experience was measured using a VAS graded from 1 to 10. The pain stimulus was given by one examiner with the same equipment yielding similar air pressure each time, while another one performed the treatments.

Teeth will be randomly assigned to three groups (N= per group) for the treatment with the three desensitizing agents.

The following dental materials were used following the manufacturers' instructions:

1. Cavex Bite&White ExSense (Cavex Holland BV, RW Haarlem, The Netherlands), a water-based mint aroma gel containing hydroxyapatite and potassium nitrate.
2. Kuraray Teethmate™ Desensitizer (Kuraray Noritake Dental, Osaka, Japan), Calcium-Phosphate-based powder and a liquid mainly water-based.
3. Ghimas Dentin Desensitizer (Ghimas, Bologna, Italy), a fluid desensitizing gel with 30% of nano-hydroxyapatite, added to 70:100 thousandths of micron-sized crystals of nano- hydroxyapatite.

Inclusion Criteria:

• patients will be considered suitable for the study if they had sensitive teeth showing abrasion, erosion, or recession with the exposure of the cervical dentine;

Exclusion Criteria:

• teeth with subjective or objective evidence of carious lesions, pulpitis, restorations, premature contact, cracked enamel, active periapical infection, or which had received periodontal surgery or root-planning up to 6 months prior to the investigation will be excluded from the study
• professional desensitizing therapy during the previous 3 months, or use of desensitizing toothpaste in the last 6 weeks.
• Patients will be also excluded if they will be under significant medication that could interfere with pain perception (e.g., antidepressants, anti-inflammatory drugs, sedatives, and muscle relaxants).

Not a plan for data sharing has been established. But, for anyone researcher would like to have this information, simply they may request them to us directly.