OR09 - The Effects of Cryotherapy Protocol on Smear Layer Removal During Endodontic Therapy

Wednesday, April 17, 2024

1:00 PM – 1:15 PM PT

Location: 511 ABC

Presenter(s)

Renee A. Smith, D.D.S.

Endodontic Resident
Wilford Hall USAF Medical Center
San Antonio, Texas

Disclosure information not submitted.

Co-Author(s)

Daniel W. Thompson, Ph.D.

Research Scientist
Naval Medical Research Unit San Antonio
San Antonio, Texas

Disclosure information not submitted.
ZM

Zachary S. McIntosh, B.Sc.

Research Associate/Statistician
Naval Medical Research Unit - San Antonio
San Antonio, Texas

Disclosure information not submitted.
TC

Timothy Carlson, D.D.S., M.S.

Assistant Program Director
University of Alabama College of Dentistry UAB
JBSA-Lackland, Texas

Disclosure information not submitted.
JS

Jelena Seibold, D.D.S., M.S.

WHASC Endodontic Residency Program Director
Wilford Hall USAF Medical Center
Lackland AFB, Texas

Disclosure information not submitted.
William B. Arden, D.D.S., Ph.D., M.P.H.

Endodontist & Health Research Scientist, Department Head of Biomaterials, NAMRU-San Antonio
Naval Medical Research Unit San Antonio
JBSA Fort Sam Houston, Texas

Disclosure information not submitted.

Abstract: Smear layer removal with ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) has been associated with better disinfection of dentinal tubules, improved sealing capabilities, and outcomes after endodontic therapy. While these irrigants are typically used at room temperature, studies have found that intracanal cryotherapy reduces inflammation and postoperative pain. Therefore, the objective of this study was to evaluate the capability of these irrigants to remove the smear layer when cooled to 2.5°C. Fifty-four extracted single-canal mandibular premolars were randomly separated into three experimental groups and chemomechanically instrumented to create a uniform smear layer, followed by a final irrigation protocol using 17% EDTA and 5.25% NaOCl at temperatures of 2.5°C, 20°C, and 37°C. Smear layer removal was compared to controls (no final irrigation) by changes in mass, scanning electron microscopy (SEM) evaluated with blinded examiners, SEM evaluated by ImageJ software analysis, and the number/size of irrigated particles measured by liquid chromatography with tandem mass spectrometry (LC-MS). Based on one-way ANOVA and Tukey’s post-hoc tests, all four analyses (mass change, examiner grading, ImageJ analysis, and LC-MS) showed no statistical difference in smear layer removal when the final irrigation protocol is performed at 2.5°C, 20°C, or 37°C (p > 0.05).5.25% NaOCl and 17% EDTA chilled to 2.5°C remove the smear layer as effectively as other tested temperatures ex vivo and could provide cryotherapy benefits if applied clinically..