Impact of repeated activation on the heat output of electric pluggers

Electric pluggers that output accurate and reliable heat are required to thermoplasticize gutta-percha for endodontic obturation. This study aimed to evaluate the accuracy and reliability of heat output by Buchanan electronic pluggers (Kerr Endodontics) after repeated activation cycles.

The Elements Obturation Unit (Kerr Endodontics) was operated in downpack mode according to the manufacturer's recommendations with a temperature of 200 °C and automatic cutoff after 4 seconds of continuous activation. Fifteen Buchanan Heat Pluggers were tested: 5 of each of sizes extra fine (XF) (0.04 taper), fine (F) (0.06 taper), and fine medium (FM) (0.08 taper). Pluggers were allowed to cool for 5 to 10 seconds between activations and were activated 25 times per day for 80 days, totaling 2,000 activations per plugger. A thermocouple and an electronic data logger were used to record a single peak temperature for each plugger at the final activation of each day.

There was no degradation in heat generation across 2,000 activations for any of the plugger sizes. Heat output for XF (0.04 taper) pluggers was significantly lower than for F (0.06 taper) and FM (0.08 taper) pluggers. Three of the 5 XF pluggers lost functionality before reaching 2,000 activations.

The heat output for F (0.06 taper) and FM (0.08 taper) pluggers was close to expected (temperatures) and did not degrade over 2,000 activations. All plugger sizes showed high variance in heat output. XF (0.04 taper) pluggers may be prone to lower temperature output than larger plugger sizes and prone to failure before 2,000 activations.