Effect of Laser and Potassium Nitrate Application on the Sensitivity Control in Bleached Teeth

Study Overview
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Brief Summary
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To investigate the effects of desensitizing agents on the dental bleaching process, testing the hypothesis that they may control dental sensitivity.

Detailed Description
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The objective of this double blind, randomized and controlled clinical study, was to evaluate the efficacy of potassium nitrate / sodium fluoride (KNO3 / KF) gel associated with LLLT (Low Level Light Therapy) on teeth that were exposed to 35% hydrogen peroxide during 3 weeks of bleaching treatment. Methods: 50 volunteers were evaluated through the split-mouth model, where the hemiarcates were randomized and later allocated in one of the experimental groups: G1 (negative control)- group with no desensitizing treatment, only bleached; G2 (positive control)- group treated with LLLT + placebo gel; G3- group treated with placebo laser application + 5% KNO3 / 2% KF gel; and G4- group treated with LLLT + 5% KNO3 / 2% KF gel.

Official Title
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Effect of Low-level Light Therapy Associated With Potassium Nitrate in the Control of Post-bleaching Dental Sensitivity: a Randomized, Double-blind, Split-mouth, Controlled Trial

Conditions
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Dentin Sensitivity

Intervention / Treatment
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* Drug: In-office dental bleaching
* Drug: Low Level Laser Therapy
* Drug: 5% potassium nitrate / 2% sodium fluoride gel


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Absence of active carious lesions; Never undergone bleaching therapy; Good oral hygiene; Do not present hypersensitivity; Do not smoke; Not being pregnant; Presence of at least 28 teeth in oral cavity. Exclusion Criteria: Presence of periodontal disease; Presence of cracks or fractures; Presence of restorations and prostheses; Presence of gastroesophageal dysfunction; Patients with severe internal dental dimming; Presence of periodontal disease; Presence of dentin exposure in anterior and/or posterior teeth.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: G1- Negative Control<br>Group with no desensitizing treatment. Prior to bleaching therapy, a water-soluble placebo gel, with non-active agent will be applied to dental vestibular surfaces. After bleaching therapy, the LASER tip will be positioned in two points (apical and cervical), without light emission (placebo). | Drug: In-office dental bleaching<br>* The group will receive in-office bleaching treatment. Three 15-minute applications of the 35% hydrogen peroxide gel were performed, totaling 45 minutes in each of the 3 sessions, with a 7-day interval.<br>* Other names: 35% hydrogen peroxide;|
| Experimental: G2- LASER (Positive Control)<br>Group treated with placebo gel before bleaching and with LLLT after in-office bleaching. | Drug: In-office dental bleaching<br>* The group will receive in-office bleaching treatment. Three 15-minute applications of the 35% hydrogen peroxide gel were performed, totaling 45 minutes in each of the 3 sessions, with a 7-day interval.<br>* Other names: 35% hydrogen peroxide;Drug: Low Level Laser Therapy<br>* It will be used the infrared spectrum with wavelength of 808 nm in its active environment AsGaAl, in two points: cervical and apical region of the incisors, canines and premolars.<br>* Other names: LLLT;|
| Experimental: G3- KNO3 (Positive Control)<br>Group treated with desensitizing gel before bleaching and after in-office bleaching, the LASER tip will be positioned in two points (apical and cervical), without light emission (placebo). | Drug: In-office dental bleaching<br>* The group will receive in-office bleaching treatment. Three 15-minute applications of the 35% hydrogen peroxide gel were performed, totaling 45 minutes in each of the 3 sessions, with a 7-day interval.<br>* Other names: 35% hydrogen peroxide;Drug: 5% potassium nitrate / 2% sodium fluoride gel<br>* 5% potassium nitrate / 2% sodium fluoride gel will be applied for 10 minutes on the vestibular surface of all pre-bleached dental elements, following the manufacturer's protocol.<br>* Other names: desensitizing therapy;|
| Experimental: G4- KNO3 + LASER<br>Group treated with desensitizing gel before bleaching and with LLLT after in-office bleaching. | Drug: In-office dental bleaching<br>* The group will receive in-office bleaching treatment. Three 15-minute applications of the 35% hydrogen peroxide gel were performed, totaling 45 minutes in each of the 3 sessions, with a 7-day interval.<br>* Other names: 35% hydrogen peroxide;Drug: Low Level Laser Therapy<br>* It will be used the infrared spectrum with wavelength of 808 nm in its active environment AsGaAl, in two points: cervical and apical region of the incisors, canines and premolars.<br>* Other names: LLLT;Drug: 5% potassium nitrate / 2% sodium fluoride gel<br>* 5% potassium nitrate / 2% sodium fluoride gel will be applied for 10 minutes on the vestibular surface of all pre-bleached dental elements, following the manufacturer's protocol.<br>* Other names: desensitizing therapy;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Stimulated pain intensity in different assessment times (P15) | The stimulated pain intensity was self reported by the patients with a modified visual analog scale, from 0 to 3, where 0 means no pain, 1 is mild pain, 2 is moderate pain and 3 is severe pain. For all groups, the patients evaluated the stimulated pain intensity two times per session: before and after the treatment in the same day. Thus, in total each patient reported the pain intensity 6 times, two times in the first day (1st session), two times in the eighth day (2nd session) and two times in the fifteenth day (3rd session). | 15 days, with assessments in the 1st, 8th and 15th day of the treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Non-stimulated pain intensity measure, (P21) | Self reported non-stimulated pain intensity was assessed daily, during 21 days, through self-perception questionnaire, answered by the patients from the first tooth bleaching session until one week after the last session. The evaluation was performed by each patient, according to a modified visual analog scale, as follows: 0- no pain, 1 mild pain, 2 - moderate pain and 3 -severe pain | 21 days |