Premium
Detection of a transitional ion concentration zone during electronic measurement of root canal length: a study in vitro
Author(s) -
Tamarut T.,
Kovačević M.,
Uhač I.
Publication year - 2000
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 - 10.1046/j.1365-2591.2000.00323.x
Subject(s) - calipers , root canal , apical foramen , dentistry , agar , chemistry , agar plate , materials science , mathematics , biology , geometry , medicine , bacteria , genetics
Aim The aim of this study was to examine the importance of a transitional ion concentration zone at the apical foramen during electronic root canal length measurement (ERCLM). Methodology The model comprised 21 extracted single‐rooted human teeth, divided into two experimental groups and one control group, each of seven teeth. The anatomical tooth length was determined from the site of reference on the tooth crown to the canal orifice and was measured using an endodontic file and a vernier caliper. Two aqueous solutions of various NaCl, KCl and CaCl 2 concentrations were mixed with agar. The Na+, K+ and Ca++ concentrations corresponded to the average value of each group as determined by atomic spectrophotometry evaluation of the extirpated human pulps. The agar containing cations was injected into the root canals after their preparation to a foramen diameter of 0.70 mm. The control teeth were then completely immersed in agar having the same concentration of cations as the agar inside the canal. In the first experimental group (group 1), the teeth were immersed in agar so that the ion concentration was higher inside the canal; in the second experimental group (group 2), the concentrations were reversed. In all three groups, ERCLM was performed by an EED 11 – resistance type device. Length d 1 was defined as the length of the root when measured to a value one degree less than the test value. Length d 2 was defined as the length of the root inducted by the test value, which corresponded to the resistance of the periapical agar. Results In group 1 the average d 1 length was 0.44 ± 1.05 shorter than the anatomical foramen (AF), and in group 2, 1.11 ± 0.43 mm longer than AF. In the control group the d 1 length was on average − 3.02 ± 3.72 mm from the AF. The d 1 values of all groups were not statistically significantly different from the anatomical length (AL). In all three experimental groups the d 2 length was statistically significantly different from the AL ( P < 0.05, t ‐test); group 1 d 2 = AL + 6.32 ± 1.38 mm; group 2 d 2 = AL + 6.27 ± 1.47; control group d 2 = AL + 9.15 ± 1.00 mm. Conclusions The results of this study indicated that when the electroconductive medium in the canal had a different ion concentration than the periapex, and the canal orifice had a wide diameter (0.70 mm), the transitional concentration zone influenced the accuracy of measurement during ERCLM with a resistance type device. When ion concentrations inside and outside the canal were identical, in teeth with a wide foramen diameter (0.70 mm or more) the lack of a transitional ion concentration zone meant that the length of the root canal could not be determined by ERCLM.