Apical Foramen Morphology According To The Length of Merged Canal at The Apex
Apical Foramen Morphology According To The Length of Merged Canal at The Apex
Apical Foramen Morphology According To The Length of Merged Canal at The Apex
Hee-Ho Kim, Jeong- Objectives: The aim of this study was to investigate the relationship between the
Bum Min, Ho-Keel apical foramen morphology and the length of merged canal at the apex in type II root
canal system. Materials and Methods: This study included intact extracted maxillary
Hwang* and mandibular human premolars (n = 20) with fully formed roots without any visible
signs of external resorption. The root segments were obtained by removing the crown
Department of Conservative
Dentistry, Chosun University School 1 mm beneath the cementum-enamel junction (CEJ) using a rotary diamond disk. The
of Dentistry, Gwangju, Korea distance between the file tip and merged point of joining two canals was defined as
Lj. The roots were carefully sectioned at 1 mm from the apex by a slow-speed water-
cooled diamond saw. All cross sections were examined under the microscope at ×50
magnification and photographed to estimate the shape of the apical foramen. The
longest and the shortest diameter of apical foramen was measured using ImageJ
program (1.44p, National Institutes of Health). Correlation coefficient was calculated
to identify the link between Lj and the apical foramen shape by Pearson’s correlation.
Results: The average value of Lj was 3.74 mm. The average of proportion (P),
estimated by dividing the longest diameter into the shortest diameter of the apical
foramen, was 3.64. This study showed a significant negative correlation between P and
Lj (p < 0.05). Conclusions: As Lj gets longer, the apical foramen becomes more ovally
shaped. Likewise, as it gets shorter, the apical foramen becomes more flat shaped.
(Restor Dent Endod 2013;38(1):26-30)
Kim HH; Min JB; Hwang HK, A thorough knowledge of the anatomy of root canal system is required to improve
Department of Conservative the success rate of endodontic treatment.1-4 Because the root canal system is complex,
Dentistry, Chosun University School canals may branch, divide, and rejoin taking various pathways to the apex. In clinical
of Dentistry, Gwangju, Korea situation, clinicians usually depend on two-dimensional radiograph for understanding
*Correspondence to the anatomy of root canal system. The early recognition of these configurations
Ho-Keel Hwang, DDS, PhD. facilitates cleaning, shaping, and obturation of the root canal system. Unfortunately,
Professor, Department of two-dimensional radiographic images do not reveal all anatomic characteristics.5,6
Conservative Dentistry, Chosun Furthermore, the apical foramen often does not represent a round shape.7 Many root
University School of Dentistry, 375
canals represent an oval or flat apical foramen that makes measuring the diameter of
Seosuk-dong, Dong-gu, Gwangju,
Korea 501-825 root canals difficult.8-10 With regard to obturation, some studies verified that many
TEL, +82-62-220-3840; FAX, +82- of the canal surfaces (especially in the apical region) are not touched during canal
62-223-9064; E-mail, rootcanal@ preparation because of the oval or irregular configuration.11-13 These untouched canal
hanmail.net surfaces may account for the failure of endodontic treatment.
※This study was supported by research fund from Chosun university dental hospital in the year of 2012.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/
by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
©Copyrights 2013. The Korean Academy of Conservative Dentistry.
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Apical foramen morphology at the apex
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Kim HH et al.
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Apical foramen morphology at the apex
were examined, and we observed the oval and flat apical Conclusions
foramen shape. In this point of view, the mechanical canal
enlargement might be insufficient for cleaning the type There was an inverse correlation between Lj and P. As
II root canal systems. Therefore, irrigations with chemical the distance between the file tip and merging point of two
solution such as NaOCl, CHX, and EDTA were also very joining canals gets longer, the apical foramen becomes
important for disinfection of the root canal.17,18 more oval shaped. Likewise, as it gets shorter, the apical
There is little controversy about the size of the apical foramen becomes more flat shaped. Therefore, clinician
preparation, and it is significant when considering the should consider the shape and size of apical foramen
best possible debridement of infected root canals. 19,20 according to the length of merged canal during root canal
To determine the size of apical preparation in clinical instrumentation in type II root canal system.
situation, clinicians might use the two-dimensional
radiographic image. This procedure reflects the clinical Conflict of Interest: No potential conflict of interest
situation. Clinician might measure the distance between relevant to this article was reported.
file tip and the merged point of joining two canals.
Jou et al. suggested constant criteria to estimate the References
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