Efficacy of a Commercial Dentifrice Containing 10% High Cleaning Silica Base, 0.5% Sodium Phytate and 0.5% Sodium Pyrophosphate on Tooth Whitening: A 8-week Clinical Study in Adults in China
Phase: NA
Conditions: Tooth Bleaching
Sponsor: Sun Yat-sen University

Official title: Whitening Efficacy of Dentifrice Containing 10% High Cleaning Silica, 0.5% Sodium
Phytate and 0.5% Sodium Pyrophosphate
NCT number: NCT04238429
Document date: 05/02/2018

Study Population and Design
This clinical trial was conducted at Guanghua School of Stomatology, Sun Yat-sen
University, Guangzhou, China, from May to October 2018. The study protocols were
approved by the institutional review board at Guanghua School of Stomatology, Sun
Yat-sen University and were in good accordance with the World Medical Association
Declaration of Helsinki on ethical aspects. This eight week study used a randomized,
double-blind, parallel-group design.
The participants were informed of the study purposes and told that their
participation was voluntary. Informed consent forms were signed. A total of 84 adults
who met with the inclusion and exclusion criteria were invited to take part in the
study. The inclusion criteria were: 1) aged 18 to 70 years old; 2) good general health;
3) able to attend the clinical examinations during the eight week study period; 4)
possessing more than 20 natural permanent teeth that were uncrowned or not
heavily filled with restorative materials, excluding third molars; 5) having a
whole-mouth mean tooth composite stain index of more than 1.5 according to the
Lobene Stain Index.(1) Exclusion criteria were: 1) severe oral diseases or chronic
diseases; 2) advanced periodontal diseases; 3) pregnant or lactating females; 4)
fluorosis or tetracycline teeth ; 5) wearing orthodontic bands or partial or removable
dentures; 6) taking part in other clinical trials; 7) receiving prophylaxis during the
previous 3 months or tooth whitening treatment during the past 6 months; 8) allergic
to the study products.
Study procedures
Eligible patients were distributed into test and control groups randomly according to
computer generated random numbers externally by a dentist. This dentist kept the
randomization and group allocation information. All the other study personnel did
not have access to the information during the course of the study.
The patients in the test group were given toothpaste containing 10% high cleaning
silica, 0.5% sodium pyrophosphate and 0.5% phytic acid, while the patients in the
control group were given a negative control toothpaste containing silica base without
any active ingredient. All toothpastes were identical in appearance and taste. The

toothpaste was marked with its specific code number which represented its group
allocation and this number was not decoded until the end of the study. The
distribution of the toothpaste was made in a separate place to ensure that other
study personnel and patients were unaware of group assignment.
The patients were asked to only use the assigned toothpaste and the same
toothbrush to brush their teeth twice daily, in the morning and in the evening, for
one minute. The patients were asked to maintain their other oral hygiene habits and
daily eating habits. The patients were not allowed to use any other toothpastes sand
oral health care products, such as mouthrinse.
The patients came to the clinic to receive clinical examinations atbaseline, 4 weeks
and 8 weeks. The same examiner provided the clinical examinations during the
course of the study. Firstly, evaluation of oral soft and hard tissues were performed.
The examiner assessed soft and hard palate, oral mucosa, tongue, sublingual and
mandibular areas, salivary glands and pharynx and larynx areas of each patient.
Secondly, tooth stain of the anterior teeth were measured using the Lobene Stain
Index. The index measures the area and intensity of extrinsic tooth stain on the facial
and lingual surfaces of six lower anterior teeth and facial surfaces of six upper
anterior teeth. The tooth surfaces were divided into two regions: body and gingival.
For each part, the intensity and extent of extrinsic tooth stain were graded on a scale
of 0-3. For stain intensity, the scale is scored as follows: 0= No stain; 1=Light stain
(yellow to light brown or gray); 2=Moderate stain(medium brown); and 3=Heavy
stain(dark brown to black). For stain area, the scale is scored as follows: 0= No stain
detected; 1= stain covering up to 1/3 of the region; 2= Stain covering >1/3 to 2/3 of
the region; and 3=Stain covering >2/3 of the region. Three variables on tooth stain
were calculated for each patient. The mean Lobene stain area, intensity and
composite scores were the sum of the scores on the the recorded regions of tooth
surfaces divided by the number of regions. The stain composite score for each region
of the tooth surfaces was the stain area score multiplied by the stain intensity
score.
At 4 weeks and 8 weeks, during the follow up examinations, the patients were also

questioned by an investigator about if they had experienced any adverse events. The
adverse events included discomfort while brushing, bitter or alteration in taste, any
allergic reactions arising from the use of the toothpastes and any feeling of changes
on oral soft tissues. Any changes in general health conditions of the patients were
also monitored.
After the patient finished each examination session, the acquired data were collected
by the facilitator who kept the data. The other study personnel had no way to access
the patient data during the course of the study.
Statistical analysis
According to the data from a previous study on tooth stain removal, the sample size
of this study was calculated. Based on a a standard deviation of 0.5 for tooth stain
area score, a reduction in the mean stain intensity scores of 20% between the test
and control groups, a power of 80%, a significance of 0.05, and an attrition of 10%, it
was estimated that 40 patients needed to be included in each group.
Chi-square test and the independent t test were conducted to compare the
differences between treatment groups on sex, age and baseline Lobene stain scores.
ANCOVA with baseline Lobene score as the covariate was conducted to compare the
differences between groups in follow-up Lobene area, intensity and composite stain
scores. For each group, paired t tests were conducted to compare the differences
between baseline and each of the two follow-ups in Lobene stain scores. All
statistical analyses were two sided and at a significance level of a = 0.05.

Study Protocol and Statistical Analysis Plan