An in Vitro Spectrophotometric Analysis of the Penetration of Bleaching Agent into the Pulp Chamber of Intact and Restored Teeth

Abstract

Aim: To investigate the pulp chamber penetration of bleaching agent in intact teeth and teeth following restorative procedure.Methodology: Sixty extracted human incisors were selected and divided into 6 Groups. Four Groups were restored with hybrid composite resin and resin modified glass ionomer cement respectively, while 2 Groups were left intact. The Groups were then immersed in the treatment agents for 60 mins at 37°C. The optical density of the resultant blue solution obtained by adding leucocrystal violet and horseradish peroxidise to the acetate buffer solution present in the pulp chamber was measured spectrophotometrically and the data thus obtained was statistically analysed using ANOVA and paired t-test. Results:The amount of pulpal peroxide penetration in restored teeth was significantly higher than intact teeth (p< 0.001). the control Group showed no peroxide penetration. Groups restored with resin modified glass ionomer cement showed higher pulpal peroxide levels than Groups restored with hybrid composites, though the difference was not statistically significant (p = 0.52). Conclusion:Peroxide readily penetrates into the pulp through intact and restored teeth, with restored teeth showing higher pulpal peroxide levels than intact teeth. Teeth restored with resin modified glass ionomer cement showed higher pulpal peroxide level than teeth restored with composite resins.

Review of the Mechanism of Tooth Whitening

“…Overall, hydrogen peroxide penetration was found to be enhanced by the following: higher hydrogen peroxide concentrations; 27,31,34,40 prolonged application; 29,31 increased temperature; 27,29 the large size of the openings of dentinal tubules in young teeth; 36 variations in the tooth structure due to location, acid-etching or restorations; 33,37,39,44,48 and light activation. 38 Penetration was also improved by specific formulations and delivery systems.…”

Clinical Investigation of 940 nm Diode Laser Power Bleaching: An In Vivo Study

“…8 The mechanism of tooth sensitivity still not fully explained and may be caused either by heat generation during light activation or pulp irritation due H 2 O 2 penetration to dental pulp. 9 The aim of this in vivo study was to observe the effectiveness of 940 nm diode laser in combination with bleaching gel by analyzing tooth sensitivity and colour change.…”

The effect of bleaching gel and (940 nm and 980 nm) diode lasers photoactivation on intrapulpal temperature and teeth whitening efficiency

“…Sensitivity usually occurs in tooth or gingiva during bleaching procedure. Although the mechanism of tooth sensitivity during tooth bleaching is not clearly understood, peroxide penetration to the dental pulp has been reported . This penetration could be reduced by decreasing the time of gel application on tooth surface .…”