Penetration of the Pulp Chamber by Bleaching Agents in Teeth Restored with Various Restorative Materials

Abstract

It is thought that externally applied bleaching agents may penetrate into the pulp chamber. This study was conducted to evaluate the diffusion of peroxide bleaching agents into the pulp chamber of teeth restored with various restorative materials. Sixty-five human extracted anterior maxillary teeth were separated into the 13 groups containing 5 teeth. Five teeth (control group) were not subjected to any cavity preparation and restoration. Standardized class V cavities were prepared in the other 60 teeth and restored using composite resin (Charisma), polyacid modified composite resin (Dyract), or resin-modified glass ionomer cement (Vitremer). All teeth were sectioned 3 mm apical to the cementoenamel junction to remove the intracoronal pulp tissue, and the pulp chamber was filled with acetate buffer to absorb and stabilize any peroxide that might penetrate. Vestibular crown surfaces of teeth in the experimental groups were subjected to four different bleaching agents for 30 min at 37 degrees C, whereas the teeth in the control groups were exposed only to distilled water. Then the acetate buffer solution in the pulp chamber of each tooth was removed, and the pulp chamber of each tooth was rinsed with 100 ml of distilled water twice. Leukocrystal violet and enzyme horseradish peroxidase were added to the mixture of the acetate buffer and rinse water. The optical density of the resulting blue solution was determined spectrophotometrically and converted into microgram equivalents of hydrogen peroxide. Higher hydrogen peroxide concentrations resulted in a higher pulpal peroxide penetration. The highest pulpal peroxide penetration was found in resin-modified glass ionomer cement groups, whereas composite resin groups showed the lowest pulpal peroxide penetration.

Effect of low-level laser therapy on odontoblast-like cells exposed to bleaching agent

“…This concentration of bleaching agent was chosen based on previous studies, and represents the amount of hydrogen peroxide that diffuses through enamel and dentin and reaches the pulp chamber after the bleaching procedures [23]. The experimental and control groups are presented in Table 1.…”

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

“…An orthodontic wire was attached to each tooth with light cure composite resin. 100µl of 2M acetate buffer was placed into the pulp chamber of each tooth to Stabilise the hydrogen peroxide that might penetrate into the pulp [2,4,5].…”

“…For restored teeth, this area corresponded to 2 mm beyond the limits of the restoration. The intact teeth were treated in the same way [2,4,5].…”

“…This technique involves both "at home" and "in office" bleaching techniques. Various concentrations of hydrogen and carbamide peroxide are used in this technique, of which 10% carbamide peroxide is the commonly used gel for "at home" bleach [1][2][3].…”

“…When a bleaching process is applied to a restored tooth, the properties of the restorative material may be affected by the bleaching agent used [2,[8][9][10][11][12].…”