Application of Endodontic Files for the Extraction of Root Tips: A Biomechanical Investigation and Case Study.
OBJECTIVE
To investigate the appropriate endodontic file for the extraction of root tips through a biomechanical study and to evaluate the clinic efficiency of this technique.


METHODS
Nine hundred molar roots were randomly divided into 3 groups (3, 5, and 7 mm) and amputated to the corresponding length. Different files were inserted into the root tips, and a pullout test was conducted using a universal testing machine. The pullout force was recorded and files with greatest pullout force were selected for clinical study. Patients' root tips were extracted using these files. The duration and incidence of postoperative complications were recorded.


RESULTS
The greatest pullout force was obtained for the 25#Hedström file, regardless of the length of the root tip and the type of file. The pullout force of Hedström files was significantly greater than that of Kerr files in each file group and root length group (P < .05). Clinically, the direct success ratio of this technique was 81.4%. The incidence of postoperative complications was very low.


CONCLUSIONS
The results of this study suggest that the application of endodontic files for the extraction of root tips is an acceptable technique. The 25#Hedström file is the optimum choice for root extraction in most cases when using endodontic files.
Attending, Orofacial Reconstruction and Regeneration Laboratory, Department of Oral and Maxillofacial Surgery, Hospital of Stomatology, Southwest Medical University, Luzhou, China.
Junliang
J
Chen
Associate Professor, Orofacial Reconstruction and Regeneration Laboratory, Department of Oral and Maxillofacial Surgery, Hospital of Stomatology, Southwest Medical University, Luzhou, China. Electronic address: heyundaidai@163.com.
Yun
Y
He
Assistant, Orofacial Reconstruction and Regeneration Laboratory, Southwest Medical University, Luzhou, China.
Qin
Q
Pan
Professor, Department of Endodontics, Hospital of Stomatology, Southwest Medical University, Luzhou, China.
Minhai
M
Nie
D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D003762:Dental Instruments; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology / Q000517:prevention & control; D011897:Random Allocation; D014081:Tooth Extraction / Q000295:instrumentation* / Q000379:methods; D014092:Tooth Root / Q000601:surgery*; D016896:Treatment Outcome