“In Vivo Study on the Possible Desensitizing Role of Hydrocortisone versus Fluoride on the Dental Pulp of Albino Rat Incisor Subjected to Bleaching”

Peroxides in the bleaching agents increase dental hypersensitivity and damage dental pulp. Hydrocortisone and fluoride have been shown to reduce this hypersensitivity. Aim of the study: This work aimed to assess the desensitizing effects of hydrocortisone and fluoride on dental pulp of Albino rat incisor subjected to whitening and to compare their effectiveness in reducing post bleaching hypersensitivity. Materials & methods: 56 adult male Albino rats were randomly divided into four groups for different treatments. Group I received no treatment. Group II had the bleaching gel applied to the incisor for 45 minutes. Group III had the bleaching gel applied similarly, followed by 0.01 ml of 1% hydrocortisone on the same surface. Group IV had the bleaching gel applied as in group II, followed by fluoride gel. Each group was further subdivided into two subgroups based on the sacrifice time: Subgroup A and subgroup B. The right side of the mandible was decalcified for histological and immunohistochemical examination using Tumor necrosing factor alpha (TNFα). Pulp tissue from the left side extirpated for substance P quantitative real-time Polymer Chain Reaction analysis (PCR). Statistical analysis was performed using SPPSS software. Results: The bleaching group showed immediate inflammatory signs that worsened over 48 hours. In the hydrocortisone –treated group, pulp inflammation initially decreased but increased again after 48 hours. In the fluoride-treated group, pulp inflammation decreased both immediately and after 48 hours. Immunohistochemical examination revealed higher TNFα expression in the bleaching group. TNFα expression decreased initially in the hydrocortisone –treated group but increased again after 48 hours. The fluoride treated group had low TNF α expression in both subgroups. PCR analysis measuring substance P (SP) showed results similar to the immnohistochemical findings. Conclusion: Dental bleaching increased pulp inflammation in rat incisors. Both hydrocortisone and fluoride reduced pulp hypersensitivity, with fluoride being more effective.