Lier 2002.

Study characteristics
Methods	Study type: RCT (split‐mouth design, 2 groups) Duration of trial: not mentioned in the study Duration of follow‐up: 16 weeks
Participants	Setting: The Institute of Clinical Dentistry, University of Oslo, Norway Inclusion criteria: the subjects had to have 2 teeth that were hypersensitive to thermal/evaporative stimulation with a blast of air Exclusion criteria: being under analgesic anti‐inflammatory, inhalation drugs or tricyclic antidepressive treatment regimens, having eating disorders, pregnancy, being under orthodontic therapy, having cognitive dysfunctions or general communication difficulties; teeth were excluded if they had been subjected to periodontal surgery within the past 3 months, had congenital enamel/dentine defects, were carious, were extensively restored or fractured, were abutments with no exposed tooth surface, were non‐vital or had symptoms of pulp damage, were under other antihypersensitive regimens within the last 30 days Total number: 17 participants enrolled and completed Age range: 26 to 66 years Sex (M/F): 3/14
Interventions	Group 1: (one side) Nd:YAG laser (wavelength: 400 μm; output: 4 W; duration: 2 minutes) Details: a Genius Laser System (Mølsgaard Dental, Denmark) with a 400 micrometers laser tip was used. Laser was first applied without a cooling system for 30 s, then for 90 s, using water as a coolant, in accordance with the manufacturer's instruction. The potency of the laser used was 4 watts, and it was applied on the buccal surface of the tooth in a mesial‐distal direction Group 2: (another side) placebo laser Details: the difference between the test and control procedures was that the laser beam was switched off during the latter, but the coolant was functioning during both
Outcomes	Responses to air blast stimuli (VAS) at baseline, and immediately after, 1 week, 4 weeks, 16 weeks after intervention
Notes	Baseline characteristics: 1. hypersensitivity reaction was provoked by means of an air blast 1 cm from the tooth surface at the cervical third of the tooth after removing supragingival plaque with a low speed handpiece with pumice powder and without fluoride. The adjacent teeth were covered by cotton rolls. The stimulus was delivered until reaction, or up to a maximum duration of 10 s. The time before reaction was recorded. All stimuli were given by 1 operator at the same dental chair with the same equipment yielding similar air pressure and temperature each time; 2. after the stimulus, the patient was asked to mark the intensity of pain on a VAS, which was marked on the left end 'no pain' and on the right end 'extreme pain' Sample size calculation: not mentioned in the study Source of funding: DICO MED AS Ethics approval: quote: "The study protocol was approved by the Regional Committee for Medical Research, Oslo, Norway" Informed consent: quote: "After having received oral and written information about the intention and the design of the study, and having signed the informed consent form, the subjects were included in the study" Adverse events: none
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information provided
Allocation concealment (selection bias)	Unclear risk	Insufficient information provided
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Due to use of placebo laser, the study might be free of performance bias It was impossible to blind personnel in this study design, but the outcome is not likely to be influenced by lack of blinding
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "The laser treatment was performed by one operator and the pain was assessed by another person"
Incomplete outcome data (attrition bias) All outcomes	Low risk	No 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 Sample size calculation was not mentioned in the study