Temperature rise on the external root surface during removal of endodontic fractured instruments.
OBJECTIVE
To investigate the temperature rise (TR) on the external root surface while preparing a staging platform, for removing intra-canal fractured instruments, using Gates Glidden (GG) drills.


METHODS
Thirty extracted mandibular incisors were decoronated and 3-3.5 mm of F3 ProTaper files were fractured 3 mm from the most coronal end of the root. Roots were divided into three groups. GG drills were used in a size-2 to size-5 sequence to prepare the staging platform coronal to the fractured segment. They were rotated at three speeds according to the study groups: group A for 2,000 revolutions per minute (rpm); group B for 4,000 rpm; and group C for 8,000 rpm. Temperature changes were recorded at the proximal and buccal or lingual external root surfaces while preparing the staging platform. Data were analyzed using the paired sample T, one- and two-ways ANOVA tests at p ≤ 0.05.


RESULTS
Overall, TR at the proximal root surface (5.44 °C) was significantly higher than that at the buccal or lingual surface (3.25 °C) (p < 0.001). Generally, TR increased significantly as the size of GG drills or the revolution speed increased (p < 0.05). GG5 drills rotated at 8,000 rpm produced the highest TR (10.85 °C). There was no interaction effect of the GG drill size and the revolution speed on TR (p = 0.272).


CONCLUSIONS
The highest TR on the external root surface, associated with preparation of a staging platform and produced by using GG drills size-5 rotating at up to 8,000 rpm, was lower than the damaging threshold.


CONCLUSIONS
A staging platform can be performed by modified GG drills (no 2 to 5) rotating at 8,000 rpm without generating a hazardous TR.
Restorative Dental Sciences Department, College of Dentistry, Taibah University, Madinah, Saudi Arabia. ahmad.madarati@hotmail.co.uk.|Endodontics & Operative Dentistry Department, Faculty of Dentistry, Aleppo University, Aleppo, Syria. ahmad.madarati@hotmail.co.uk.
A A
AA
Madarati
School of Dentistry, The University of Manchester, Manchester, United Kingdom.
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DC
Watts
D003762:Dental Instruments; D004708:Endodontics / Q000295:instrumentation*; D006801:Humans; D013696:Temperature