Document Type


Date of Degree

Spring 2016

Degree Name

MS (Master of Science)

Degree In

Operative Dentistry

First Advisor

SoRan Kwon

Second Advisor

Phillip Wertz


Objectives: Evaluate and assess the effect of an innovative double layer, single application desensitizing/whitening technique on Nitrate penetration and total color change. Methods: Specimens were prepared from extracted caries free human molars (n=160). Teeth were randomly assigned into four groups: 100μl 25% hydrogen peroxide “Philips Zoom chairside” as control group (CTRL), double layer treatment of 20μl 5% potassium nitrate “Relief ACP, Philips oral care” and 100μl 25% hydrogen peroxide (DL20), double layer treatment of 40μl 5% potassium nitrate and 100μl 25% hydrogen peroxide (DL40), and one layer treatment of 40 μl 5% potassium nitrate (PN40). Spectrophotometric color measurements (Vita EasyShade) were done at base line (T0), one day (T1), and one month (T2) following the treatment. Nitrate penetration was measured using a nitrate/nitrite assay kit. Group comparisons of tooth color difference measurements, and nitrate penetration readings were made using the Kruskal-Wallis test. Adjustment was made for pairwise treatment comparisons using the Tukey method in conjunction with an overall 0.05 level of significance. Results: 160 teeth were used. Color difference (ΔE) results at (T1) and (T2) showed no significant difference among the CTRL, DL20, DL40 groups. But there was a statistical significant difference between those groups and the single layer (PN40) group (p

Public Abstract

For dentists, tooth whitening is a great aid for reaching patient expectations of a flawless smile. However, a major drawback of tooth whitening is tooth sensitivity. Potassium nitrate has been recommended to lessen tooth sensitivity in which it is applied in a tray prior to the tooth whitening treatment. This technique is time consuming and inconvenient, so companies incorporated potassium nitrate into the tooth whitening gel to make it a more time efficient technique. Due to the similar penetration rate of both potassium nitrate and tooth whitening gel and the lower molecular weight of tooth whitening gel, there is the assumption of the tooth whitening gel penetrating first through the tooth and onto the pulp in which it will leave it in an excitation state, by the time potassium nitrate reaches the pulp it will be too late to have the desired effect.

So the purpose of this study is to innovate a one step technique that is less time consuming and will allow for potassium nitrate to penetrate first followed by hydrogen peroxide to interact with the stain molecules. An in vitro study to assess the effectiveness of 25% hydrogen peroxide tooth whitening agent, in terms of tooth color change when preceded by different amounts of potassium nitrate gel as a desensitizing agent was conducted. This technique is Time efficient technique, convenient technique for both the patient and the clinician, and it will pave the road for future approaches to manage tooth sensitivity.


publicabstract, Double layer, Hydrogen peroxide, Potassium nitrate, Tooth sensitivity, Tooth whitening


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Acknowledgment: Whitening materials were provided by Philips oral healthcare.


Copyright 2016 Abdullah Mohammed Alshehri