Does the first file to bind correspond to the diameter of the canal in the apical region?

AIM The aim of this study was to determine whether the first file that binds at the working length corresponds to the canal diameter. METHODOLOGY Two similar groups (n = 10) of mandibular premolars with curved canals were selected on the basis of their morphology. Following access and pulp tissue removal, the first instrument that bound in each canal at the working length was determined. In one group the instrument used was a K-file, in the other group a Lightspeed instrument was used. After fixing the instruments in place, the apices were ground to the level of the working length and the diameters of both the instrument and the apical canal were recorded. RESULTS In 75% of the canals, the instruments bound at one side of the wall only; in the other 25%, the instrument did not contact the wall. In 90% of the canals, the diameter of the instrument was smaller than the short diameter of the canal; this discrepancy was up to 0.19 mm. No significant difference in discrepancy was found between instruments (P > 0.05). CONCLUSIONS Neither the first K-file nor the first Lightspeed instrument that bound at the working length accurately reflected the diameter of the apical canal in curved mandibular premolars. It is uncertain whether dentine can be removed from the entire circumference of the canal wall by filing the root canal to three sizes larger than the file that binds first.

[1]  P. Wesselink,et al.  An in vitro experiment on the effect of an attempt to create an apical matrix during root canal preparation on coronal leakage and material extrusion. , 2001, Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics.

[2]  P. Wesselink,et al.  Viable bacteria in root dentinal tubules of teeth with apical periodontitis. , 2001, Journal of endodontics.

[3]  P R Wesselink,et al.  Prevalence and extent of long oval canals in the apical third. , 2000, Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics.

[4]  A Lussi,et al.  Comparison of two devices for root canal cleansing by the noninstrumentation technology. , 1999, Journal of endodontics.

[5]  L S Buchanan,et al.  The standardized-taper root canal preparation, Part 1: Concepts for variably tapered shaping instruments. , 1999, Dentistry today.

[6]  J. Siqueira,et al.  Histological evaluation of the effectiveness of five instrumentation techniques for cleaning the apical third of root canals. , 1997, Journal of endodontics.

[7]  E. Verdes,et al.  A comparative study of seven instruments in shaping the root canal in vitro. , 1997, International endodontic journal.

[8]  P R Wesselink,et al.  Efficacy of three techniques in cleaning the apical portion of curved root canals. , 1995, Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics.

[9]  P J Lumley,et al.  Cleaning of oval canals using ultrasonic or sonic instrumentation. , 1993, Journal of endodontics.

[10]  R E Walton,et al.  Histologic evaluation of three endodontic instrument/preparation techniques. , 1992, Endodontics & dental traumatology.

[11]  E Sonnabend,et al.  The influence of different root canal instruments on root canal preparation: an in vitro study. , 1991, International endodontic journal.

[12]  E. Hoshino,et al.  Predominant obligate anaerobes invading the deep layers of root canal dentin. , 1990, International endodontic journal.

[13]  M. Tang,et al.  The effects of hand, sonic and ultrasonic instrumentation on the shape of curved root canals , 1989 .

[14]  Richard E. Walton,et al.  Principles and Practice of Endodontics , 1989 .

[15]  R. Walton,et al.  An in vitro histological comparison of the step-back, sonic, and ultrasonic instrumentation techniques in small, curved root canals. , 1987, Journal of endodontics.

[16]  M Lucotte,et al.  [Endodontic therapy]. , 1985, Le Chirurgien-dentiste de France.

[17]  G. Armitage,et al.  Cemental changes in teeth with heavily infected root canals. , 1983, Journal of endodontics.

[18]  R E Hand,et al.  Analysis of the effect of dilution on the necrotic tissue dissolution property of sodium hypochlorite. , 1978, Journal of endodontics.

[19]  S. W. Schneider,et al.  A comparison of canal preparations in straight and curved root canals. , 1971, Oral surgery, oral medicine, and oral pathology.