CTRG Funded Research

Evaluation of TTX-Resistant Sodium Channels in Patients with Irreversible Pulpitis - AAE Foundation Grant

  Although most clinical endodontic procedures are performed with either no pain or minimal pain, a small proportion of patients experience incomplete anesthesia and continue to report pain during non-surgical procedures.  These patients often present with at least moderate pain due to irreversible pulpitis in mandibular molar {1,2}.  Although several proposals have been advanced to explain this clinical problem, we propose to test the hypothesis that there is an upregulation of tertrodotoxin (TTX)-resistant sodium channels on pulpal nerves in teeth with a diagnosis of irreversible pulpitis.  The TTX-resistant classes of sodium channels have recently been cloned, are expressed on nociceptors, and, importantly, are resistant to both TTX and local anesthetics.  According to this hypothesis, patients may experience pain after local anesthetic injection due to incomplete blockage of the TTX-resistant sodium channels found on nociceptors.

HYPOTHESIS:  Pulp collected f4rom teeth with a clinical diagnosis of irreversible pulpitis have a greater concentration of TTX-resistant sodium channels than pulp collected from control teeth.

Specific Aim 1:  To determine tissue expression levels of the PN3 (a TTX-resistant) sodium channel in pulps with a diagnosis of irreversible pulpitis versus control pulps (third molars) using western immunoblots and scanning densitometric analysis.

Specific Aim 2:  To determine tissue expression levels of the NaN (a TTX-resistant) sodium channel in pulps with a diagnosis of irreversible pulpitis versus control teeth (third molars) using western immunoblots and scanning densitometric analysis.