Bleaching gel mixed with MI Paste Plus reduces penetration of H 2 O 2 and damage to pulp tissue and maintains bleaching effectiveness

Bleaching gel mixed with MI Paste Plus reduces penetration of H 2 O 2 and damage to pulp tissue and maintains bleaching effectiveness:

Abstract

Objectives

MI Paste Plus remineralizer (Rem) strengthens dental structures after bleaching. We investigated the effect of Rem on the penetration of hydrogen peroxide (H₂O₂), bleaching effectiveness, and pulp inflammation after bleaching.

Materials and methods

Bovine disks were grouped as follows (n = 10): control (untreated), bleached (Ble; 35% H₂O₂, 30 min), Ble-Rem (H₂O₂ followed by Rem, 30 min), Rem-Ble (Rem followed by H₂O₂), Rem-Ble-Rem (Rem before and after H₂O₂), and Ble+Rem (mixture of Rem with H₂O₂, 1:1, 30 min). The penetration of H₂O₂ was quantified and bleaching efficacy was analyzed. Upper rat molars (n = 10) received the same treatments at random. The rats were euthanized after two days and 30 days, and their jaws were removed for histological analysis. Statistical tests were performed (P < 0.05).

Results

The bleached groups, except Ble+Rem (P > 0.05), showed significant H₂O₂ penetration compared with control (P < 0.05). Color alteration analysis showed that ΔL and ΔE were significantly higher in the bleached groups than those in control (P < 0.05); the Δb of the bleached groups differed from that of control at 24 h (P < 0.05). At two days, necrosis or inflammation was observed in the bleached groups compared with control (P < 0.05), except Ble+Rem, which was similar to control (P > 0.05). At 30 days, tertiary dentin formation was significant in the bleached groups (P < 0.05), except Ble+Rem (P > 0.05).

Conclusion

The mixture of MI Paste Plus and bleaching gel reduces H₂O₂ penetration and pulp damage and maintains bleaching effectiveness.

Clinical relevance

Because bleaching can damage dental tissues, we studied a new bleaching protocol that reduces damage to the pulp tissue while maintaining bleaching efficiency: a single application of 30 min of MI Paste Plus mixed with 35% H₂O₂ bleaching gel (1:1).