Alencar 2020.

Study characteristics
Methods	Study type: RCT (double‐blinded). 4 parallel groups Duration of trial: not mentioned in the study Duration of follow‐up: 1 month
Participants	Setting: not mentioned in the study. Authors' affiliation is School of Dentistry, Federal University of Para, Belem, PA, Brazil Inclusion criteria: volunteers aged between 18 and 50 years, who were students and employees of the local university, were recruited. The main inclusion criterion was the presence of 2 to 4 hypersensitive teeth with shallow non‐carious cervical lesions up to 1 mm deep, according to Van Landuyt et al, Class I gingival recession according to the Miller classification, or both. The sensitive teeth should present a score > 4 on the VAS for the evaporative stimulus Exclusion criteria: systemic diseases, pulpitis, carious lesions, defective restorations, active periodontal disease, use of analgesic medication, pregnant or lactating women, and the use of professional desensitizing treatment received during the previous 3 months Total number: 32 participants with 83 teeth Age range: 18 to 50 years Sex (M/F): 15/17
Interventions	Before the treatments, all the volunteers received professional prophylaxis and a kit containing a soft bristle toothbrush and toothpaste without desensitizing action. Patients were instructed to brush their teeth 3 times a day. The treatments were performed in 2 sessions with a 24‐hour interval After the randomization process (block randomization), the patients were allocated into 4 groups Group 1: (n = 19 teeth): GPlacebo ‐ simulated PBM (without light emission) followed by the application of nHAP‐free toothpaste Group 2: (n = 18 teeth): GLaser ‐ PBM followed by the application of nHAP‐free toothpaste Group 3: (n = 18 teeth): GnHAP ‐ simulated PBM followed by the application of nHAP Group 4: (n = 18 teeth): GLasernHAP ‐ PBM followed by the application of nHAP
Outcomes	Dentine hypersensitivity was evaluated at 4 evaluation times: baseline (immediately before the 1st session), after the 1st session, after the 2nd session, and 1 month after the 2nd session. The evaluation of pain sensitivity was performed by means of a tactile stimulus followed by an evaporative stimulus associated with a VAS (0 to 10). A 5‐minute interval between tactile and evaporative stimuli was performed
Notes	Sample size calculation: described in detail Source of funding: the authors declared no conflict of interest Ethics approval: quote: "it was approved by the local university ethics committee (No. 2,402,287)" Informed consent: quote: "All participants in the study signed the informed consent form after being duly informed in accordance with the declaration of Helsinki" Adverse events: not mentioned in the study
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Block randomization was performed, aiming to balance the sample number in the number of existing arms. The number of eight volunteers in each block was predefined. For the formation of each block a stratified randomization was performed considering the sex and age strata. After the formation of the block, a simple numerical draw was carried out among the participants, and subsequently, every two volunteers were allocated to compose one of the four groups. The total number of blocks in the study was four"
Allocation concealment (selection bias)	Low risk	Quote: "Allocation secrecy was maintained throughout the sample compounding process. One of the co‐authors of the study was responsible for the formation of the blocks, numerical drawing within the block and allocation of the sample in the groups. The numerical drawing was performed using numbered and coded papers, for which the volunteers, clinical operator and evaluator did not know to which group the subject was allocated"
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "The evaluator and the patient were blinded. The volunteers evaluated in the experiment were also not aware of the treatment to which they were submitted. Both the Nano‐P desensitizer and the placebo toothpaste had the same color and visual appearance. The materials were placed in identical containers so that the patients were not identified at the time of application of the product"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "The evaluator and the patient were blinded. The study had only one evaluator to assess pain sensitivity, who did not participate in the randomization process"
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No descriptions on loss to follow‐up
Selective reporting (reporting bias)	Low risk	All intended outcomes were reported in the study
Other bias	Low risk	No other sources of bias were identified