Neuropeptide Y Regulates Neurogenic Pulp Inflammation

Objective. This study assessed the neuropeptide Y (NPY) expression in healthy human dental pulp following tooth bleaching with three in-office hydrogen peroxide-based systems: Opalescence Boost© (Ultradent Products, South Jordan, UT), Pola Office© (SDI, Victoria, Australia), and Zoom© (Zoom! Bleaching System; Discuss Dental, Culver City, CA).

Materials and Methods. Forty dental pulps were collected from healthy premolars scheduled for extraction for orthodontic reasons. Teeth were divided into four groups containing ten healthy premolars each: Control group (n= 10): the teeth were not exposed to dental bleaching agents (healthy pulps assessed for normal/basal NPY values). Pola Office system group (n= 10): application of Pola office (35% H2O2) for 8 minutes. Opalescent Boost system group (n= 10): application of Opalescent Boost (40% H2O2) for 20 minutes. Zoom system group (n= 10): application of Zoom! (25% H2O2 + cold blue light) for 15 minutes. The investigators rigorously followed the manufacturer's instructions for all bleaching systems. Following the extractions, the pulpal tissue was collected, placed in a 4% formaldehyde solution in Eppendorf tubes, and processed. NPY levels were measured using enzyme-linked immunosorbent assay (ELISA).