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The effect of irrigation time, root morphology and dentine thickness on tooth surface strain when using 5% sodium hypochlorite and 17% EDTA
Author(s) -
Sobhani O. E.,
Gulabivala K.,
Knowles J. C.,
Ng Y.L.
Publication year - 2010
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/j.1365-2591.2009.01655.x
Subject(s) - sodium hypochlorite , dentistry , saline , molar , irrigation , smear layer , crown (dentistry) , materials science , dentin , chemistry , medicine , biology , agronomy , organic chemistry , endocrinology
Sobhani OE, Gulabivala K, Knowles JC, Ng Y‐L. The effect of irrigation time, root morphology and dentine thickness on tooth surface strain when using 5% sodium hypochlorite and 17% EDTA. International Endodontic Journal , 43 , 190–199, 2010. Abstract Aim To evaluate the effect of irrigation with 5% sodium hypochlorite (NaOCl) alone and in conjunction with 17% ethylenediaminetetraacetic acid (EDTA) on tooth surface strain (TSS) and to analyse the influence of irrigation time, root morphology and dentine thickness. Methodology Thirty‐six single‐rooted pre‐molars with single canals had their crown and enamel reduced and root canals prepared using a standardized protocol. Teeth were grouped according to anatomical criteria and randomly distributed to experimental irrigation groups: (A) saline (negative control); (B) 5% NaOCl (positive control); (C) 5% NaOCl alternated with 17% EDTA. TSS was measured using electrical strain gauges bonded to the cervico‐proximal part of the tooth. Teeth, mounted in clear acrylic resin placed in a universal testing machine, were subjected to nine consecutive 10‐min irrigation periods followed by non‐destructive occlusal loading to record TSS. Statistical analysis was carried out using two‐way hierarchical anova and post hoc multiple comparisons. Results Two groups showed an increase in TSS from the baseline (initial 10‐min irrigation with saline). Group A showed a negligible reduction of 1.2% (343–339 με), which was not statistically significant ( P = 0.7). Group B showed a highly significant ( P = 0.001) increase in TSS by 53.7% (178–253 με), and group C showed a significant ( P = 0.02) increase in TSS by 17.4% (163–192 με). The rate of change in TSS was significantly different between test groups. The length of the tooth ( P = 0.04) as well as the mesio‐distal ( P = 0.05) width had significant effects on TSS. Conclusions Irrigation with 5% with or without 17% EDTA increased TSS. The increase was significantly greater with 5% NaOCl alone than with 5% NaOCl alternated with 17% EDTA in contrast to previous findings with longer duration of irrigant exposure. Tooth length and mesio‐distal root width significantly contributed to the increase in TSS.