Concentrations of and application protocols for hydrogen peroxide bleaching gels: Effects on pulp cell viability and whitening efficacy

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• 作者：Diana Gabriela Soares ; Fern ; a Gon莽alves Basso ; Josimeri Hebling ; Carlos Alberto de Souza Costa
• 关键词：Tooth bleaching ; Dental pulp ; Odontoblasts ; Cytotoxicity
• 刊名：Journal of Dentistry
• 出版年：February, 2014
• 年：2014
• 卷：42
• 期：2
• 页码：185-198
• 全文大小：3521 K

文摘

Objectives

To assess the whitening effectiveness and the trans-enamel/trans-dentinal toxicity of experimental tooth-bleaching protocols on pulp cells.

Methods

Enamel/dentine discs individually adapted to trans-well devices were placed on cultured odontoblast-like cells (MDPC-23) or human dental pulp cells (HDPCs). The following groups were formed: G1 - no treatment (control); G2 to G4 - 35% H₂O₂, 3 脳 15, 1 脳 15, and 1 脳 5 min, respectively; and G5 to G7 - 17.5% H₂O₂, 3 脳 15, 1 脳 15, and 1 脳 5 min, respectively. Cell viability and morphology were evaluated immediately after bleaching (T1) and 72 h thereafter (T2). Oxidative stress and cell membrane damage were also assessed (T1). The amount of H₂O₂ in culture medium was quantified (Mann-Whitney; 伪 = 5%) and colour change (螖E) of enamel was analysed after 3 sessions (Tukey's test; 伪 = 5%).

Results

Cell viability reduction, H₂O₂ diffusion, cell morphology alteration, oxidative stress, and cell membrane damage occurred in a concentration-/time-dependent fashion. The cell viability reduction was significant in all groups for HDPCs and only for G2, G3, and G5 in MDPC-23 cells compared with G1. Significant cell viability and morphology recovery were observed in all groups at T2, except for G2 in HDPCs. The highest 螖E value was found in G2. However, all groups presented significant 螖E increases compared with G1.

Conclusion

Shortening the contact time of a 35%-H₂O₂ gel for 5 min, or reducing its concentration to 17.5% and applying it for 45, 15, or 5 min produce gradual tooth colour change associated with reduced trans-enamel and trans-dentinal cytotoxicity to pulp cells.

Clinical significance

The experimental protocols tested in the present study provided significant tooth-bleaching improvement associated with decreased toxicity to pulp cells, which may be an interesting alternative to be tested in clinical situations intended to reduce tooth sensitivity and pulp damage.