Efficacy of three techniques in cleaning the apical portion of curved root canals

doi:10.1016/S1079-2104(05)80134-9

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology

Volume 79, Issue 4, April 1995, Pages 492-496

https://doi.org/10.1016/S1079-2104(05)80134-9 Get rights and content

Various techniques for root canal instrumentation may have different effects in cleaning curved root canals, especially their apical portions. One hundred thirty-five mesiobuccal canals with an average curvature of 25 degrees from human mandibular molars were treated with step-back, crown-down pressureless, or balanced-force techniques with 2% sodium hypochlorite used as an irrigant. The cleaning efficacy of these techniques was evaluated by counting the remaining surface debris under a stereomicroscope with a calibrated eyepiece micrometer. The results indicated that the apical portion of the canal was less clean than the middle and coronal portions regardless of the technique performed and that the balanced-force technique produced a cleaner apical portion of the canal than did the other techniques studied.

References (27)

HeuerMA
The biomechanics of endodontic therapy
Dent Clin North Am
(1963)
SchilderH
Cleaning and shaping the root canal
Dent Clin North Am
(1974)
SjögrenU et al.
Bacteriologic evaluation of ultrasonic root canal instrumentation
Oral Surg Oral Med Oral Pathol
(1987)
KlaymanSM et al.
A comparison of the efficacy of serial preparation versus Giromatic preparation
J Endod
(1975)
BolanosOR et al.
Scanning electron microscope comparisons of the efficacy of various methods of root canal preparation
J Endod
(1980)
GoldmanM et al.
A comparison of three methods of cleaning and shaping the root canal in vitro
J Endod
(1988)
WeineFS et al.
The effect of preparation procedures on original canal shape and on apical foramen shape
J Endod
(1975)
GoerigAC et al.
Instrumentation of root canals in molars using the step-down technique
J Endod
(1982)
KesslerJO et al.
Comparison of the relative risk of molar root perforations using various endodontic instrumentation techniques
J Endod
(1983)
MorganLF et al.
An evaluation of the crown-down pressureless technique
J Endod
(1984)

RoaneJB et al.

The “balanced force” concept for instrumentation of curved canals

J Endod

(1985)

SchneiderSW

A comparison of canal preparations in straight and curved root canals

Oral Surg Oral Med Oral Pathol

(1971)

CoffaeKP et al.

The effect of serial preparation versus nonserial preparation on tissue removal in the root canal of extracted mandibular human molars

J Endod

(1975)

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Citation Excerpt :
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Efficacy of three techniques in cleaning the apical portion of curved root canals

Dent Clin North Am

Dent Clin North Am

Oral Surg Oral Med Oral Pathol

J Endod

J Endod

J Endod

J Endod

J Endod

J Endod

J Endod

J Endod

Oral Surg Oral Med Oral Pathol

J Endod