Investigation of chemical changes in sealers during application of the warm vertical compaction technique.

By Viapiana R, Baluci C , Tanomaru-Filho M & Camilleri J

Date: 03/2016
Journal: JOE

Summary: 

Purpose:  To assess (i) heat generated by pluggers during warm vertical compaction of gutta-percha and investigation

of temperature changes on the external root surface during canal filling, and (ii) the chemical changes of root canal sealers induced by heat.

•N= 4 types of sealers (AH plus, MTA plus and 2 experimental sealers), continuous  wave pluggers with 4 tapers (0.06, 0.08, 0.10 and 0.12)

•Materials/Methods:

•The sealers were characterized by scanning electron microscope,  X-ray energy dispersive analysis (SEM-EDX) X-ray diffraction analysis (XRD). •Temperature changes on the system B pulggers tips during heating (preset at 200 °C) and external temperatures generated on the root surface during warm vertical compaction of gutta-percha with different sealers inside the root canal were monitored using an infrared thermography camera. •Chemical changes induced by heating the sealers were assessed by Fourier transform infrared (FT-IR) spectroscopy.

Most highlighted Results: 

•MTA Plus and the experimental sealers were composed of a cement and radiopacifier, with epoxy resin or a water-soluble polymer as dispersant, whilst AH Plus was epoxy resin-based.

•The heat generated at the tips of the system B pluggers was found to be lower than the temperature set and indicated on the device LCD display (maximum was 78.5 °C by 0.08 taper).

•The sealers reduced the heat generated on the external root surfaces during the heating phase by 10 °C.

•AH Plus exhibited changes to its chemical structure after exposure to heat, whilst the other sealers were unaffected.

Clinical significance: 

The use of sealer reduced the temperature generated at the external root surface to between 37–41 °C for all sealers, which is tolerated by the bone and periodontium. A temperature of 47 °C (10 °C above body temperature) for 1 min is sufficient to cause necrosis of the alveolar bone,