Effect of an Anti-inflammatory on Tooth Sensitivity Caused by Bleaching
Condition: Color Changes During Tooth Formation
MeSH terms: Dentin Sensitivity
Study type: Interventional

Summary: 
      Perhaps the use of a more selective anti-inflammatory drug, capable of inhibiting enzyme
      specific for pain may be more effective in preventing the tooth sensitivity caused by the
      inflammatory response produced by in-office bleaching. To the extent of the authors´
      knowledge, no study has so far addressed the use of a selective anti-inflammatory drug
      specific for pain enzyme on tooth sensitivity, being this the aim of the present
      investigation.
    

Detailed description: 
      Study design This was a randomized, triple-blind, placebo-controlled, parallel-group clinical
      trial, with an equal allocation rate to receive either one of two treatments. The study took
      place in the clinic of the Brazilian Association of Dentistry in Guarapuava, Paraná from
      August 2010 to December 2010.

      Inclusion and exclusion criteria

      Patients included in this clinical trial were at least 18 years old and had good general and
      oral health. Participants were recruited by means of radio and TV advertisement. A total of
      247 participants were examined in a dental chair to check whether they met the inclusion and
      exclusion criteria. The participants were required to have six caries-free maxillary anterior
      teeth, without resto- rations on the labial surfaces. The central incisors had to be shade C2
      or darker as judged by comparison with a value- oriented shade guide (Vita Lumin, Vita
      Zahnfabrik, Bad Säckingen, Germany). Participants who had undergone tooth-whitening
      procedures, presented anterior restorations, were pregnant/lactating, had severe internal
      tooth discoloration (tetracycline stains, fluorosis, and pulpless teeth), were taking any
      type of medicine, had bruxism habits, or any other pathology that could cause sensitivity
      (such as recession and dentin exposure) were excluded from the study, since they would not be
      immediately eligible for a cosmetic treatment, such as bleaching. Participants who reported
      some earlier or present health problems in the stomach, heart, kidney and liver, or
      participants continuously using any with anti-inflammatory and antioxidant action were
      excluded from the study. Sample size calculation The primary outcome of this study was the
      absolute risk of TS. The absolute risk of TS was reported to be approximately 86 % for the
      bleaching product Whiteness HP Maxx (FGM, Joinville, SC, Brazil). Thus, 30 patients were
      required to have an 80 % chance of detecting, as significant at the two-sided 5 % level, a
      de- crease in the primary outcome measure from 86 % in the control group to 41 % in the
      experimental group.

      Study intervention

      Participants were randomly stratified by sex into the placebo and etoricoxib groups. The
      randomization process was performed by computer-generated tables by a third person not
      involved in the research protocol. Details of the allocated groups were recorded on cards
      contained in sequentially numbered, opaque, sealed envelopes. These were prepared by a third
      person not involved in any of the phases of the clinical trial. Once the participant was
      eligible for the procedure, and completed all baseline assessments, the allocation assignment
      was revealed by this envelope being opened by the mentioned third person. Neither the
      participant nor the operator knew the group allocation, both being blinded to the protocol.

      The participants from the placebo group received a placebo (Talco pharma SM-200-Henrifarma
      produtos químicos e farmacêuticos LTDA, São Paulo, SP, Brazil) and participants from the
      etoricoxib group received a dose of a selective COX- 2 inhibitor etoricoxib 60 mg (Arcoxia,
      MSD, Campinas, SP, Brazil). All the participants were watched to ensure that they took the
      drugs or placebo 1 h before treatment. The drugs were similar in appearance. A second dose of
      placebo or etoricoxib (60 mg) was administered 24 h after the first dose. At the time the
      participants were required to take the second dose of the medicine, the research auxiliary
      called him/her and asked him/her to take the medicine. This procedure was implemented to
      increase adherence to the protocol.

      The gingival tissue of the teeth to be bleached was isolated using a light-polymerized resin
      dam (Top Dam, FGM, Joinville, SC, Brazil). The 35 % hydrogen peroxide gel (Whiteness HP Maxx,
      FGM) was used in three 15-min applications for both groups in accordance with the
      manufacturer's directions. The in-office bleaching agent was refreshed every 15 min during
      the 45-min application period. Two bleaching sessions with 1 week interval between them were
      performed. All participants were instructed to brush their teeth regularly using fluoridated
      toothpaste (Sorriso Fresh, Colgate- Palmolive, São Paulo, SP, Brazil).

      Shade evaluation

      Shade evaluation was recorded before and 30 days after the bleaching treatment using two
      methods: subjective evaluation using a shade guide (Vita Lumin, Vita Zahnfabrik, Bad
      Säckingen, Germany) and an objective evaluation using the spectrophotometer (Easyshade,
      Vident, Brea, CA).

      For the subjective examination, the 16 shade guide tabs were arranged from highest (B1) to
      lowest (C4) value, so that the color C2 was set. Although this scale is not linear in the
      truest sense, the changes were treated as though they represented a continuous and
      approximately linear ranking for the purpose of analysis. The measurement area of interest
      for shade matching was the middle one third of the facial surface of the anterior central
      incisor. For calibration purposes, five patients who were not included in the sample because
      they were used in the pilot study, participated in the training phase of this study. The two
      examiners, blinded to the allocation assignment, scheduled these patients for bleaching and
      evaluated their teeth against the shade guide at baseline and 30 days after the procedure.
      The two examiners were required to have an agreement of at least 85 % (Kappa statistic)
      before beginning the study evaluation. For the objective evaluation, a preliminary impression
      of the maxillary arch was made using dense silicone Adsil (Vigodent S/A Indústria e
      Comércio, Rio de Janeiro, RJ, Brazil). The impression was extended to the maxillary canine
      and served as a standard color measurement guide for the spectrophotometer. A window was
      created on the labial surface of the molded silicone guide for the central incisor to be
      evaluated. The window was made using a metal device with well-formed borders, with a radius
      of 3 mm. Only one operator took all the measurements in all 30 patients, using Vita Easyshade
      (Easyshade, Vident, Brea, CA) before and 30 days after the bleaching therapy. The shade was
      determined using the parameters of the Easyshade device where the following values were
      indicated: L*, (a*), and (b*), in which L* represents the value from 0 (black) to 100 (white)
      and a* and b* represent the shade, where a* is the measurement along the red-green axis and
      b* is the measurement along the yellow-blue axis. The color comparison before and after
      treatment is given by the difference between the two colors (ΔE), which is calculated using
      the formula: ΔE=((ΔL*)2+(Δa*)2+(Δb*) 2)1/2.

      TS evaluation

      The patients recorded their perception of TS during the first and second bleaching sessions
      using three pain scales. A 5-point verbal rating scale (0 = none, 1 = mild, 2 = moderate, 3 =
      considerable, and 4 = severe], a 0 to 100 numerical rating scale and a visual analogue scale
      using a 10-cm horizontal line with words "no pain" at one end and "worst pain" at the
      opposite end were used in this study. Subjects were asked to record whether they experienced
      TS during the treatment up to 1 h after, from 1 to 24 h and from 24 to 48 h after bleaching.
      The worst scores/numerical values obtained in both bleaching sessions were considered for
      statistical purposes. The values were arranged into two categories: percentage of patients
      that reported TS at least once during treatment (absolute risk of TS) and overall TS
      intensity.

      Statistical analysis

      The analysis was performed after the intention-to-treat protocol and involved all
      participants who were randomly assigned. The statistician was blinded to the study groups.
      The agreement between the examiners' objective evaluation was evaluated using the kappa
      statistic. The primary outcome absolute risk of TS was compared by using the Fisher's exact
      test at a 5 % level of significance. The relative risk as well as the confidence interval for
      the effect size was calculated.

      TS intensity (secondary outcome) was also statistical- ly analyzed. The mean/median and
      standard deviation/interquartile range of the three pain scales were calculated. Color
      change, another secondary endpoint, was used to assess the efficacy of the bleaching
      treatment. For subjective evaluation, the means and standard deviations of SGU at baseline
      and 30 days after bleaching for each group were calculated. In order to evaluate whether the
      bleaching therapies were effective or not, the data from SGU of both groups were submitted to
      a two-way repeated measures ANOVA. A post-hoc analysis (Tukey's test) was used to make
      pairwise comparisons. The ΔL, Δa, Δb, and ΔE values were evaluated by Student's t test.

      The data sets were plotted on histograms and inspected for normal distributions. Some data
      did not appear to be normally distributed, and therefore, nonparametric statistical tests
      were used to compare the various treatments. Statistical analyses of three pain scales
      comparing the two groups at the three different assessment points were performed using the
      Mann- Whitney U test. Comparisons between times within each group were performed using the
      Friedman tests. In all statistical tests, the significance level was set at p = 0.05 values
      less than or equal to 5 % indicated significant differences.
    

Intervention name(s): Etoricoxib; Placebo
Intervention type(s): Drug; Other
Intervention description(s): Group 2 - experimental Etoricoxib will receive two doses of selective anti-inflammatory to enzyme cyclooxygenase 2 (COX-2) (Etoricoxib 60 mg) given once every 24 hours;; Group 1 - Control Group will receive two doses of placebo tablet administered a every 8 hours,
Other intervention name(s): Anti-inflamatory; Placebo group
Intervention MeSH terms: Etoricoxib
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: bleaching agent; tooth bleaching; sensibility