Study of the Intra-Coronal Pressure Generated by Internal Bleaching Agents and Its Influence on Temporary Restoration

Abstract

Intra-coronal bleaching is a treatment that whitens non-vital teeth from within the pulp chamber, a procedure by which oxygen and free radicals are released. This in vitro study analyzed and compares the oxygen expansion produced when different bleaching agents encounter dental tissues during this type of bleaching. Here, 120 lower incisors were included and prepared to achieve conditions as close as practicable to internal bleaching with the walking bleach technique. The access cavity of the lingual surface was prepared to seal glass tubes with oil inside them by adhesive restoration once the bleach was placed inside the pulp chamber. The following bleaching groups were used: hydrogen peroxide (HP) 30% (n = 30), sodium Perborate (SP) with distilled water (n = 30), a mixture of HP 30% with SP (n = 30) and a control group (n = 30). After 10 days, the oil displacement that took place through the tube due to oxygen release was measured daily. Displacement of the oil was observed in all groups except the control group. The final mean expansion at 10 days was 335.24 ± 76.85 mm for the HP 30% group, 8.40 ± 1.74 mm for the SP group and 183.07 ± 49.93 mm for the HP30% + SP mixture. Significant statistical differences were observed between the three groups using the Games–Howell post hoc test, where HP30% caused the greatest expansion and SP the least expansion. These results suggest that the higher the amount of HP in the sample, the more oxygen expansion is observed, so that temporary restoration must be performed more carefully to avoid displacement.

Effects of Dental Bleaching Agents on the Surface Roughness of Dental Restoration Materials

“…In order to improve the aesthetic appearance of patients, doctors very frequently resort to dental bleaching, carried out with professional products [ 13 , 14 , 15 ].…”

Clinical Testing of Walking Bleach, In-Office, and Combined Bleaching of Endodontically Treated Teeth

“…Urea remarkably penetrates the enamel, affects the interprismatic region, and denaturalizes the proteins, producing a structural change in enamel and dentin. The action of urea on hard dental tissues enables better permeability for hydrogen peroxide and free radicals [ 1 , 26 ].…”

“…Dental dyschromia varies in etiology, location, and severity, and its origin may be related to extrinsic causes, intrinsic causes, or a combination of both. A detailed study of the case must be carried out to make an accurate diagnosis, since the success of the treatment and the accuracy of the results will depend on it [ 1 ].…”

“…The bleaching of endodontically treated teeth is based on dentin permeability, allowing the oxidizing agent to penetrate directly into the pigment in the dentin, and eliminate or alleviate the problem of discoloration [ 9 , 10 ]. The oxidizing chemical agent removes intrinsic stains via chromogenic degradation, and by breaking down the larger pigments into smaller ones, the color of the teeth is lightened [ 1 ].…”

Comparative Study of the Expansive Behaviour of Different Internal Bleaching Agents

“…With the Walking Bleach intracoronal bleaching technique, it has been observed that the temporary seal that is placed once the bleaching agents have been introduced into the chamber becomes deficient. This probably occurs due to an increase in intracameral pressure caused by the interaction of the bleaching agents with the dental tissues [20][21][22][23]. Inadequate sealing may lead to certain problems, such as intracameral contamination due to the introduction of bacteria through the microscopic gap between the restoration and the tooth.…”