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Azerbaycan Saytlari

 »  Home  »  Endodontic Articles 4  »  A comparison of the shaping characteristics of two nickel–titanium endodontic hand instruments
A comparison of the shaping characteristics of two nickel–titanium endodontic hand instruments
Discussion - References.

Comparison of the amount of removed dentine in conjunction with the preparation time represents the efficiency of an instrument. The S-files removed more dentine than the K-type files (Stenman & Spångberg 1990), possibly because the rake angle of the S-file is positive compared to the K-file (Schafer 1997). In this study, the preparation times tended to be shorter for Ni–Ti K-files compared to Ni–Ti S-files in all groups (Table 1). An explanation for this finding is the fact that the Ni–Ti S-files removed significantly more dentine at the most coronal level compared to the Ni–Ti K-files. The circumferential instrumentation of unflared canals requires substantial dentine removal at this level and the more effective the instrument the more dentine is removed at the most coronal level. This dentine removal resulted in a longer preparation time and increased fatigue for the operator.
Procedural accidents such as zip and elbow formation were observed in straight root canals. This surprising result may be explained by the morphology of human root canals. Roots grouped as ‘straight’ do actually have slightly curved canals (Dobo-Nagy et al. 1995). Our conception concerning the relatively high prevalence of procedural accidents in straight canals is discussed in our previous paper (Dobo-Nagy et al. 1997b). In the present study no significant differences were observed between the two instruments in terms of procedural accidents. However, semiquantitative methods for observing the prevalence of perforations, blockage or zip and elbow formation are not adequate for determining fine differences between instruments.
The preparation asymmetry measurement (Dobo- Nagy et al. 1997a,b) is a sensitive quantitative method for determining the transportation of root canals. Using this method the Ni–Ti S-file produced greater transportation at the apical as well as at the danger zone in J-form canals. The differences in transportation between the two instruments in the J-form canal group may be explained by the different designs of the two instruments. The positive rake angle combined with unbalanced preparation of Ni–Ti S-files delivered an increased hour-glass shape in abrupt curvatures. This implies that the Ni–Ti K-files should be chosen for abrupt curvatures in preference to Ni–Ti S-files. Comparison of transportation values according to root canal forms revealed a statistically significant difference between J- and C-form canals prepared with Ni–Ti S-files. This observation may be explained by the increased effectiveness of the Ni–Ti S-files in the coronal part of the canal. This simplified root canal form modified by the instrument itself delivered significantly better results in the C-form canal group prepared with Ni–Ti S-files.


Al-Omari MAO, Dummer PMH, Newcombe RG (1992) Comparison of six endodontic files to prepare simulated root canals. Part 1. International Endodontic Journal 25 , 57-66.
Briseno BM, Sonnabend E (1991) The influence of different root canal instruments on root canal preparation: an in vitro study. International Endodontic Journal 24 , 15-23.
Carvalho LAP, Bonetti I, Borges MAG (1999) A comparison of molar root canal preparation using stainless-steel and nickel-titanium instruments. Journal of Endodontics 25 , 807- 10.
Dob?-Nagy C, Szab? J, Szab? J (1995) A mathematically based classification of root canal curvatures on natural human teeth. Journal of Endodontics 21 , 557-60.
Dob?-Nagy C, Bartha K, Bern?th M, Verdes E, Szab? J (1997a) A comparative study of seven instruments in shaping the root canal in vitro. International Endodontic Journal 30 , 124- 32.
Dob?-Nagy C, Bartha K, Bern?th M, Verdes E, Szab? J (1997b) The effect of root canal morphology on canal shape following instrumentation using different techniques. International Endodontic Journal 30 , 133-40.
Elliott LM, Curtis RV, Pitt Ford TR (1998) Cutting pattern of nickel-titanium files using two preparation techniques. Endodontics and Dental Traumatology 14 , 10-5.
Forsberg J (1992) A method for experimental dental radiography. International Endodontic Journal 25 , 93-6. Gambill JM, Alder M, del Rio CE (1996) Comparison of nickel- titanium and stainless steel hand-file instrumentation using computed tomography. Journal of Endodontics 22 , 369- 75.
Harlan AL, Nicholls JI, Steiner JC (1996) A comparison of curved canal instrumentation using nickel-titanium or stainless steel files with the balanced-force technique . Journal of Endodontics 22 , 410-3.
Mullaney TP (1979) Instrumentation of finely curved canals. Dental Clinics of North America 23 , 575-92.
Schafer E (1997) Root canal instruments for manual use: a review. Endodontics and Dental Traumatology 13 , 51- 64.
Stenmann E, Spangberg LSW (1990) Machining efficiency of endodontic K-files and Hedstrom files. Journal of Endodontics 16 , 375-82.