Substance P and Neuropeptide Y Expression in Dental Pulp Following Traumatic Injuries

Luxations are the most common and avulsion is the most serious of all traumatic dental injuries. It is well established that neuropeptides play a role in the inflammatory response. However, the presence of neuropeptides in the dental pulp following trauma have not been established. Objective: To evaluate the expression of Substance P (SP) and Neuropeptide Y (NPY) in the dental pulp following different traumatic injuries (subluxation, lateral luxation, and avulsion). Materials and Methods: Following endodontic access, samples were collected from the pulp of patients receiving root canal therapy after traumatic injury (n = 43). Pulps from healthy teeth extracted for orthodontic reasons were used as control (n = 10). SP and NPY expression was determined by ELISA. Results were analyzed using Student’s T test (p < 0.0001) or One-Way ANOVA with Dunn’s correction (p < 0.05). Results: Avulsion demonstrated higher expression of SP and NPY than subluxation and lateral luxation regardless of the pulpal status. Subluxation and lateral luxation demonstrated similar levels of SP and NPY. However, when the pulpal diagnosis was taken in consideration, irreversible pulpitis showed higher levels than necrotic pulps, and lateral luxation showed higher expression of SP and NPY than subluxation. Conclusions: Our results showed that avulsion presents higher expression of SP and NPY than subluxation and lateral luxation. Pulpal diagnosis correlates with SP and NPY expression in cases of subluxation and lateral luxation, showing higher levels in irreversible pulpitis.