Hypersensitivity and Color Changes of Bleached Teeth Using Different Remineralizing Agents
Condition: Tooth Hypersensitivity
MeSH terms: Dentin Sensitivity; Hypersensitivity
Study type: Interventional

Summary: 
      The aim of this in vivo study is to evaluate the post-bleaching enamel hypersensitivity and
      the possible color changes following the application of arginine and nano-hydroxyapatite
      remineralizing solutions after enamel bleaching using an in-office chemical bleaching agent.
      A commercial Fluoride remineralizing and desensitizing agent will be used as the control
      group. Following bleaching of the anterior teeth and then the application of the different
      tested remineralizing agents; the patients will be assessed for post-bleaching
      hypersensitivity using the visual analogue scale (VAS) to describe the severity of the
      hypersensitivity from mild to moderate to severe. On the other hand, the baseline shade and
      post-bleaching color changes will be evaluated using a shade guide. The data will be
      collected and tabulated then the statistical analysis will be performed.

      The null hypothesis is that the different tested remineralizing agents will have a similar
      effect on the post-bleaching teeth hypersensitivity & the color changes of the bleached
      teeth.
    

Detailed description: 
      Recently, there has been several patients that favor the in-office bleaching technique due to
      its quick and satisfying aesthetic outcome, nevertheless clinical research reported some
      clinical adverse effects. Teeth hypersensitivity is the most common adverse effect of teeth
      bleaching. It was suggested that hydrogen peroxide can pass to the pulp through enamel and
      dentin to create an inflammatory reaction or directly stimulate the neural receptors
      triggering pain sensation.

      It was reported that tooth sensitivity during bleaching has a range of 18-78%. Usually, teeth
      hypersensitivity subsides upon accomplishment of the bleaching procedure, but occasionally it
      may cause the patient to withdraw from form the treatment session. Different methods and
      approaches with a varying rate of success have been advocated to reduce teeth sensitivity,
      such as decreasing the rate of application, using different desensitizing agents before or
      after bleaching procedure, desensitizing agent incorporation into the bleaching gel, and
      decreasing the concentration of bleaching agent. In this context, the efficacy of
      desensitizing obliteration agents to prevent and treat the post-bleaching hypersensitivity
      has been investigated in many clinical trials presenting promising results. These
      obliterating agents can enhance the enamel mineral content, impeding hydrogen peroxide
      infiltration to the nerve endings and thereby hypersensitivity is much reduced or even
      eliminated.

      Study design:

      This randomized clinical study will use the "excel sheet" for randomization and assigning the
      subjects into the respective test groups.

      All the included subjects will sign an informed consent before participating in this clinical
      study, in full accordance with the World Medical Association Declaration of Helsinki.

      Settings and locations:

      From the pre-determined inclusion and exclusion criteria, a total of 33 volunteers will be
      enrolled for the study. The clinical study will be performed from March 2021, through June
      2021, in the outpatient dental clinic at the National Research Centre in Egypt.

      Sample size calculation:

      An equivalence test of means using two one-sided tests based on data from a previous study
      resulted in a design of 11 patient in each group (control and treatment groups) as minimum
      sample sizes and will achieves 92% power at a 5.0% significance level when the true
      difference between the Visual Analogue Scale (VAS) means is 0.3, the standard deviation is
      0.3, and the equivalence limits are -0.7 and 0.7.

      Tested materials:

      The materials to be used in the study will be: an in-office hydrogen peroxide
      chemical-activated bleaching kit: Opalescence™ Boost™ 40% hydrogen peroxide Tooth Whitening
      System (Ultradent Products, Inc., South Jordan, UT, USA) and three desensitizing agents: a
      commercially available UltraEZ desensitizing gel (Ultradent Products, Inc., South Jordan, UT,
      USA) and 2.5% concentration of arginine and nano-Hydroxy apatite solutions.

      Sample grouping:

      The enrolled 33 participants will be randomly divided into three groups (n=11) according to
      the "Coin-Toss method", representing the investigated remineralizing and desensitizing agent
      to be received after bleaching of their maxillary and mandibular anterior teeth with a 40%
      hydrogen peroxide in-office chemical-activated bleaching agent as follows:

      Group I : UltraEZ desensitizing gel application after bleaching (control). Group II : 2.5%
      Arginine solution application after bleaching. Group III: 2.5% nano-hydroxyapatite solution
      application after bleaching.

      In-office teeth bleaching:

      Pre-operative hypersensitivity will be determined and recorded for all enrolled subjects
      using the VAS method.

      Baseline shade color of the predetermined teeth will be recorded using Classical VITAPAN
      shade guide.

      The in-office bleaching procedure will be performed using Opalescence™ Boost™ 40% Tooth
      Whitening System (Ultradent Products, Inc., South Jordan, Utah, USA) chemical bleaching agent
      according to the manufacturer instructions.

      Preparation of arginine and nano-hydroxyapatite solutions:

      Two and a half g of arginine powder (Sigma-Aldrich, St. Louis, MO, USA), and 2.5 g of
      nano-hydroxyapatite powder (Sigma-Aldrich, St. Louis, MO, USA) will be weighed with a digital
      balance then mixed with 100 ml of distilled water to obtain a 2.5%-concentration of arginine
      and nano-hydroxyapatite solutions.

      Application of the remineralizing agents:

      A commercially available fluoride agent "UltraEZ gel (Ultradent Products, Inc., South Jordan,
      UT, USA)" will be applied to the teeth of the assigned patients of Group I and left
      undisturbed for 20 min as recommended by the manufacturer. Then the patients will be
      instructed to rinse their teeth thoroughly with water. The 2.5% prepared solutions of
      arginine and nano-hydroxyapatite will be applied to the bleached teeth of the assigned
      patients of Group II and Group III respectively, using micro brushes in a generous amount to
      the labial surfaces of the bleached teeth and left undisturbed for 20 min. Then the patients
      will be instructed to rinse their teeth thoroughly with water.

      Post-operative hypersensitivity evaluation:

      The post-operative hypersensitivity of the bleached maxillary anterior teeth will be recorded
      immediately after bleaching then once again after application of the remineralizing agents at
      the same session. Tooth sensitivity will be evaluated using a 3-way syringe at 5 to 10 cm
      distance using the Visual Analogue Scale (VAS). Whereby, readings from 0-10. Zero denoting no
      sensitivity, 1-3 is presented as mild, 4-7 is presented as moderate and 8-10 is presented as
      severe sensitivity. After that, it will be recorded on daily bases for the first week by the
      participants who will be asked to bring their records in the follow-up sessions. Then the
      postoperative hypersensitivity will be evaluated in-office every week for a 3-week follow-up
      period using the VAS scoring system. All the readings will be recorded in a self-structured
      proforma.

      Post-operative color evaluation:

      The post-bleaching shades of the maxillary anterior teeth will be recorded immediately after
      bleaching, then once again after application of the desensitizing agents at the same session.
      Afterwards, it will be recorded every week for a 3-week follow-up period using VITAPAN
      classical A1-D4® shade guide at the middle third of the anterior maxillary teeth. The 16 tabs
      of the VITAPAN classical shade guide were arranged in descending numerical order regarding
      the value from B1 to C4. Then these values were converted into code numbers using a
      conversion table.
    

Intervention name(s): Remineralizing agent I application; Remineralizing agent II application; Remineralizing agent III application
Intervention type(s): Other; Other; Other
Intervention description(s): Application of UltraEZ remineralizing agent to the bleached teeth; Application of 2.5% arginine solution to the bleached teeth; Application of 2.5% nano-hydroxyapatite solution to the bleached teeth
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Parallel interventional study model
Masking: Single (Participant)
Primary purpose: Prevention
Keywords: Teeth bleaching; Remineralizing agents; Arginine solution; Nano-hydroxyapatite solution; Hypersensitivity; Color changes