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Effects of increased apical enlargement on the amount of unprepared areas and coronal dentine removal: a micro‐computed tomography study
Author(s) -
Pérez A. R.,
Alves F. R. F.,
MarcelianoAlves M. F.,
Provenzano J. C.,
Gonçalves L. S.,
Neves A. A.,
Siqueira J. F.
Publication year - 2018
Publication title -
international endodontic journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.988
H-Index - 119
eISSN - 1365-2591
pISSN - 0143-2885
DOI - 10.1111/iej.12873
Subject(s) - coronal plane , root canal , post hoc , dentistry , reduction (mathematics) , computed tomography , medicine , dentin , orthodontics , mathematics , anatomy , radiology , geometry
Aim To evaluate the effects of progressive apical enlargement on the amount of unprepared root canal surface area and remaining dentine thickness. Methodology The root canals of 30 extracted mandibular incisors with Vertucci′s type I configuration were instrumented with rotary HyFlex CM instruments (Coltene‐Whaledent, Altstätten, Switzerland) up to 4 instruments larger than the first one that bound at the working length ( WL ). Teeth were scanned in a micro‐computed tomography (micro‐ CT ) device before canal preparation and after instrumentation with the 2nd, 3rd and 4th larger instruments. The amount of unprepared surface area in the full canal or in the apical 4 mm as well as the remaining dentine thickness at 10 mm from the WL were calculated and compared. The general linear model for repeated measures adjusted by Bonferroni's post hoc test was used for statistic analysis. Results There was a significant reduction in the amount of unprepared areas after each increase in preparation size ( P < 0.01). This was observed for both the full canal length and the 4‐mm apical segment. The amount of remaining dentine was also significantly reduced after each file size ( P < 0.01). However, dentine thickness always remained greater than 1 mm, even after using the largest instrument. Conclusion Apical preparations up to 4 instruments larger than the first one to bind at the WL caused a significant progressive reduction in the unprepared canal area.