Trial design
This study protocol is a two-arm parallel pilot randomized controlled trial, and it was developed in accordance with the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) and Consolidated Standards of Reporting Trials (CONSORT) guidelines (14, 15). A SPIRIT checklist is attached in Additional file 1.
Participant timeline
To describe the time schedule of enrolment, intervention and assessment, a SPIRIT figure and a CONSORT flow chart are mentioned in Table 2 and Figure 1.
Table 2. SPIRIT figure
|
Enrolment
|
Post-allocation
|
Timepoint
|
0
|
4 weeks
(range: 3-5 weeks)
|
Enrolment:
|
- Eligibility screen
|
X
|
|
- Informed consent
|
X
|
|
- Allocation
|
X
|
|
Intervention:
|
- CAREDYNE Shield
|
X
|
|
- Nanoseal
|
X
|
|
Clinical assessment:
|
- Air blow
|
X
|
X
|
- Inspection
|
X
|
X
|
- Palpation
|
X
|
X
|
Study setting
All procedure of this study will be performed in Department of Periodontology and Endodontology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Sample size
There are no previous clinical studies which investigate the effectiveness of CAREDYNE Shield on DH; therefore, at least 15 participants will be required in each group to perform a sample size calculation in a subsequent study (16). With a 20% dropout rate, a total of 40 participants will be recruited in this study.
Eligibility screen
When DH complaints are presented from patients in Nagasaki University Hospital, eligibility criteria described in Table 3 are verified by the dentist in charge of the patient.
Table 3. eligibility criteria
Inclusion criteria
|
Outpatients
|
Participants who presented with DH complaint
|
Participants who agreed to attend this study after informed consent
|
Exclusion criteria
|
Participants who have allergy to desensitizing materials used in this study
|
Participants who are pregnant or lactating
|
Participants taken DH treatment within the last 6 months
|
Participants with systemic disease that mislead the results of this study
|
Participants who presented with pain complaints that mislead the results of this study
|
DH teeth with restoration that mislead the results of this study
|
DH teeth with caries or advanced periodontal disease
|
DH teeth taken periodontal surgery or orthodontic treatment within the last 3 months
|
DH: dentin hypersensitivity
Informed consent
After eligibility screen, the potential participants who met eligibility criteria will be taken informed consent with the informed consent form attached in Additional file 2. Then, they will be enrolled in this study by an examiner who will be blinded to the allocation. Signed informed consent form is mandatory for enrollment.
Randomized allocation
After enrollment, baseline assessments will be performed by the examiner who enrolled the participant in this study. Then, randomized allocation will be performed in a 1:1 ration by the dentist in charge of the patient with opaque sealed envelopes which prepared before participant recruitment and on which “Nanoseal” or “CAREDYNE Shield” is printed. Participants allocated in the intervention group will be treated with CAREDYNE Shield; meanwhile, participants allocated in the control group will be treated with Nanoseal. The information of desensitizers used in this study is described in Table 4.
Table 4. Desensitizers used in this study.
Material
|
Manufacturer
|
Composition
|
CAREDYNE Shield
|
GC Dental Industrial Corporation,
Tokyo, Japan
|
Solution A: Fluorozinccalciumsilicate glass
Solution B: 10-15% phosphoric acid
|
Nanoseal
|
Nippon Shika Yakuhin Co., Ltd.,
Shimonoseki, Japan
|
Solution A: Fluoroaluminocalciumsilicate glass
Solution B: 10% phosphoric acid
|
Allocation concealment
After the allocation, the operator who performed allocation will record operator’s name, baseline date and type of teeth to be treated in the allocation list. The list will not contain the allocated group name to conceal allocation and participant’s name and ID number to protect personal information. Allocation information will be recorded in the electric carte which other research staffs cannot check without any browsing history.
Blinding of participants
Participants will be blinded during this study and disclosure of allocation to participants will be performed in the case described as follows: (1) participant requests to stop or change allocated intervention, (2) worsening disease or new disease occurs, (3) continuing this study is judged to be inappropriate for the participant and (4) this study is terminated.
Intervention
After randomized allocation, the participants in the intervention group will be treated with CAREDYNE Shield and the participants in the control group will be treated with Nanoseal by the operator who performed allocation. Prior to the application of CAREDYNE Shield or Nanoseal, dental prophylaxis and water rinse will be performed to remove plaque deposits; the areas to be treated will be isolated with cotton rolls and dried with cotton pellets; two equal proportions of solution A and solution B will be mixed with micro-brush and applied to the dentin surface for 20 seconds; then, rinsed with water. 4 weeks after the treatment, clinical assessments will be performed by the examiner who enrolled the participant in this study.
During this study, other any dental treatment to DH teeth are prohibited, and all intervention procedure will be recorded by the operator in electronic chart to improve adherence to intervention protocols. Discontinuing intervention will be performed in the case described as follows: (1) participant requests to stop or change allocated intervention, (2) worsening disease or new disease occurs, or (3) continuing this study is judged to be inappropriate.
Primary outcome
Primary outcome is the reduction of pain intensity in response to air stimuli measured with 5-points verbal response scale from baseline to 4 weeks after the intervention. To evaluate the pain level, air blast will be applied with a three-way dental syringe after the isolation of the DH teeth with cotton rolls; then, participants will be asked verbally to rate the level of pain intensity with 5-points verbal rating scale (VRS; a numerical scale from 0 to 4 summarized in Table 5).
Table 5. Verbal Rating Scale
Score
|
Level of pain intensity
|
0
|
no pain
|
1
|
mild pain
|
2
|
moderate pain
|
3
|
severe pain
|
4
|
extremely intense pain
|
Secondary outcome
Secondary outcomes are the change of gingival condition near the treated area measured with the gingival index (GI) and the change of oral hygiene status at the treated dentin surface measured with the plaque index (PI) from baseline to 4 weeks after the intervention (17, 18). GI and PI will be evaluated with inspection and palpation.
Data collection
Outcome assessment will be performed at baseline and 4 weeks after the intervention by the examiner who enrolled the participant in this study. Calibration was performed to promote data quality. Examiner’s name, date of assessment, type of teeth and the acquired outcomes will be recorded in the assessment form and it will be given to the lead principal investigator (PI).
Data management
Double data entry will be performed by two research staffs independently. To protect confidentiality, the correspondence table of the anonymizing code and participant’s names will be prepared, and all documents containing personal information obtained in this study will be kept strictly in lockable filing cabinets in the office for more than 5 years after this study; then, discarded through a shredder.
Statistical design
The primary outcome will be analyzed with Fisher's exact test and the analysis will be conducted according to the intention-to-treat principle. Participants who discontinue or deviate from intervention protocols or with any missing data will be excluded. Any additional analyses will not be performed.
Access to data
PI will have access to the final study data and make the final decision to terminate this study. Other research staffs will not access to any data acquired in this study.
Monitoring
Monitoring will be performed by one of our research staffs according to the standard operating procedures and the results will be given to PI within 2 weeks after monitoring. When adverse events or other unintended effects of the intervention happen, PI will perform appropriate treatments to the participant, report to the Nagasaki University Hospital Clinical Research Ethics Committee (REC) and share this information with the research staffs. Data monitoring committee is not necessary because the DH treatment with Nanoseal or CAREDYNE Shield is general practice and low-invasive intervention procedure.
Potential benefits and harms
This study will contribute to the future clinical improvements. Meanwhile, atopic dermatitis is the potential side effect of the intervention.