Universität zu Köln

Heberer, Marie-Therese, Roggendorf, Hubert C., Faber, Franz-Josef, Lawrenz, Nicolai-Alexander, Frankenberger, Roland ORCID: 0000-0002-5112-4463 and Roggendorf, Matthias J. (2022). Longitudinal craze line propagation in human root dentin after instrumentation with NiTi rotary files of different instrument tapers after long-term chewing simulation. Clin. Oral Investig., 26 (3). S. 2671 - 2680. HEIDELBERG: SPRINGER HEIDELBERG. ISSN 1436-3771

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Abstract

Objectives The aim of this study was to investigate whether file design and taper significantly influence microcrack initiation during machine preparation. Materials and methods Sixty extracted teeth with straight single canals were selected. The teeth were randomly assigned to four groups based on their root canal anatomy and the corresponding NiTi rotary file system (I, Mtwo; II, ProTaper Universal; III, F6 SkyTaper; control, no preparation and filling). The root canals of the experimental groups were filled using the single-cone technique. The tested teeth were all subjected to a mechanical chewing simulation with flat lead loading over a period of 3 years (corresponding to 150,000 cycles). The teeth were checked for dentinal defects (accumulative crack growth in length) under the digital microscope (Keyence VHX-5000) at time 0 (baseline prior to chewing simulation) and after 3, 6, 12, 24, and 36 months of loading. The cumulative crack increase was statistically analyzed using the Kruskal-Wallis test, Jonckheere-Terpstra test, and the Wilcoxon rank-sum test. The significance was set at p < 0.05. Results In contrast to preparation with greater-tapered instruments, ProTaper Universal (group II) and F6 SkyTaper (group III) instrumentation with the smaller tapered Mtwo files (group I) showed less accumulative propagation of craze lines (p < 0.05) at all time points. Conclusion Instruments with greater taper for root canal instrumentation should be used with care to avoid negative long-term effects in the form of propagation of dentinal defects over time. A positive cutting-edge angle and a smaller taper have a positive effect on a lower craze line development.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Heberer, Marie-Therese UNSPECIFIED UNSPECIFIED UNSPECIFIED Roggendorf, Hubert C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Faber, Franz-Josef UNSPECIFIED UNSPECIFIED UNSPECIFIED Lawrenz, Nicolai-Alexander UNSPECIFIED UNSPECIFIED UNSPECIFIED Frankenberger, Roland UNSPECIFIED orcid.org/0000-0002-5112-4463 UNSPECIFIED Roggendorf, Matthias J. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-579220
DOI:	10.1007/s00784-021-04238-3
Journal or Publication Title:	Clin. Oral Investig.
Volume:	26
Number:	3
Page Range:	S. 2671 - 2680
Date:	2022
Publisher:	SPRINGER HEIDELBERG
Place of Publication:	HEIDELBERG
ISSN:	1436-3771
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CANAL PREPARATION; SHAPING ABILITY; CLEANING EFFECTIVENESS; MICROCRACK FORMATION; MTWO INSTRUMENTS; END PREPARATION; CRACK FORMATION; SURFACE STRAIN; TREATED TEETH; F6 SKYTAPER Multiple languages Dentistry, Oral Surgery & Medicine Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/57922