Trial design
This study protocol is a two-arm parallel pilot randomized controlled trial; that 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 enrollment, intervention and assessment, a SPIRIT figure and a CONSORT flow chart are presented in Table 2 and Figure 1.
Table 2. SPIRIT figure
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Enrolment
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Post-allocation
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Timepoint
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0
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4 weeks
(range: 3-5 weeks)
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Enrolment:
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- Eligibility screen
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X
|
|
- Informed consent
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X
|
|
- Allocation
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X
|
|
Intervention:
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- CAREDYNE Shield
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X
|
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- Nanoseal
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X
|
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Clinical assessment:
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- Air blow
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X
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X
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- Inspection
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X
|
X
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- Palpation
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X
|
X
|
Study setting
All procedures of this study will be performed at the Department of Periodontology and Endodontology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Sample size
No previous clinical studies have investigated 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 patients present with DH complaints at Nagasaki University Hospital, clinical diagnosis will be performed by the dentist in charge of the patient. Short and sharp pain which will arise in response to air stimuli or tactile stimuli will be assessed with three-way dental syringe or an explorer, caries or restoration will be assessed with a dental mirror and an explorer, severe periodontal diseases will be assessed with a dental mirror and a periodontal prove and the information about medical/dental history will be obtained by interview. Then, the eligibility criteria described in Table 3 will be verified.
Table 3. eligibility criteria
Inclusion criteria
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Outpatients
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Participants who presented with a DH complaint
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Participants who agreed to participate in this study after providing their informed consent
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Exclusion criteria
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Participants who have an allergy to the desensitizing materials used in this study
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Participants who are pregnant or lactating
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Participants who have undergone DH treatment within the last six months
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Participants with systemic diseases that might influence the results of this study
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Participants who present with pain complaints that might influence the results of this study
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DH teeth with restoration that might influence the results of this study
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DH teeth with caries or advanced periodontal disease
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DH teeth that have undergone periodontal surgery or orthodontic treatment within the last three months
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DH: dentin hypersensitivity
Informed consent
After eligibility screen, the potential participants who met the eligibility criteria will be asked for their informed consent using the informed consent form attached in Additional file 2. They will be then enrolled in this study by an examiner blinded to the allocation. A 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. Randomized allocation will then be performed in a 1:1 ratio by the dentist in charge of the patient with opaque sealed envelopes prepared before participant recruitment and on which “Nanoseal” or “CAREDYNE Shield” is printed. Participants allocated to the intervention group will be treated with CAREDYNE Shield, while those allocated to the control group will be treated with Nanoseal. The information on the desensitizers used in this study is described in Table 4.
Table 4. Desensitizers used in this study.
Material
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Manufacturer
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Composition
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CAREDYNE Shield
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GC Dental Industrial Corporation,
Tokyo, Japan
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Solution A: Fluorozinccalciumsilicate glass
Solution B: 10-15% phosphoric acid
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Nanoseal
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Nippon Shika Yakuhin Co., Ltd.,
Shimonoseki, Japan
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Solution A: Fluoroaluminocalciumsilicate glass
Solution B: 10% phosphoric acid
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Allocation concealment
After the allocation, the operator who performed allocation will record the 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 in order to conceal the allocation as well as the participant’s name and ID number for personal information protection. Allocation information will be recorded in the electronic medical record system which research staff cannot check without leaving a record of their browsing history.
Blinding of participants
Participants will be blinded during this study and disclosure of allocation to participants will be performed in the following cases: (1) participant requests to stop or change the allocated intervention, (2) worsening disease or new disease occurs, (3) continuing this study is judged to be inappropriate for the participant or (4) this study is terminated.
Intervention
After randomized allocation, the participants in the intervention group will be treated with CAREDYNE Shield, and those 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 a micro-brush and applied to the dentin surface for 20 seconds, followed by rinsing with water. Four weeks after the treatment, clinical assessments will be performed by the examiner who enrolled the participant in this study.
During this study, any other dental treatment to DH teeth are prohibited, and all intervention procedures will be recorded by the operator in an electronic chart to improve adherence to intervention protocols. Discontinuing intervention will be performed in the following case: (1) participant requests to stop or change the allocated intervention, (2) worsening disease or new disease occurs, or (3) continuing this study is judged to be inappropriate.
Primary outcome
The primary outcome is the reduction of pain intensity in response to air stimuli measured with a five-points verbal rating scale (VRS) from baseline to four weeks after the intervention. To evaluate the pain level, an air blast will be applied with a three-way dental syringe after the isolation of the DH teeth with cotton rolls, participants will then be asked verbally to rate the level of pain intensity using a five-points VRS (numerical scale from 0 to 4 summarized in Table 5).
Table 5. Verbal rating scale
Score
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Level of pain intensity
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0
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no pain
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1
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mild pain
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2
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moderate pain
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3
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severe pain
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4
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extremely intense pain
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Secondary outcome
Secondary outcomes are the change in the gingival condition near the treated area measured with the gingival index (GI) and the change in the oral hygiene status at the treated dentin surface measured with the plaque index (PI) from baseline to four weeks after the intervention (17, 18). The GI and PI will be evaluated with inspection and palpation.
Data collection
Outcomes will be assessed at baseline and four weeks after the intervention by the examiner who enrolled the participant in this study. Calibration was performed to promote the data quality. The 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.
Data management
Double data entry will be performed by two research staff independently. To ensure confidentiality, all documents obtained in this study will be kept strictly in lockable filing cabinet in the office for at least five years after this study, before being destroyed using a shredder and discarded.
Statistical design
The primary outcome will be analyzed with Fisher's exact test according to the intention-to-treat principle. Participants who discontinue or deviate from the intervention protocols or with any missing data will be excluded. No additional analyses will be performed.
Access to data
The principal investigator will have access to the final study data and make the final decision to terminate this study. No other research staff will have access to any data acquired in this study.
Monitoring
Monitoring will be performed by one of our research staff according to the standard operating procedures and the results will be given to the principal investigator within two weeks after monitoring. When adverse events or other unintended effects of the intervention happen, the principal investigator will perform appropriate treatments for the participant, report the incident to the Nagasaki University Hospital Clinical Research Ethics Committee (REC) and share this information with the research staff. A data monitoring committee is not necessary because DH treatment with Nanoseal or CAREDYNE Shield is general practice and a low-invasive intervention procedure.
Potential benefits and harms
This study will contribute to future clinical improvements. However, atopic dermatitis is a potential side effect of the intervention.