Endodontics: NiTi
Dentsply PathFiles
This Dentsply video shows PathFiles being used to prepare a glide path prior to Rotary NiTi canal prep. PathFiles are Rotary Nickel-Titanium.
PathFile advantages include:
• Ledging is unlikely
• Foramen is not transported
• Can get round steep curves
I understand. Do not show this message again.
Dentsply PathFiles
A "Glide Path" needs to exist before introducing a Rotary NiTi file for canal prep, or the tip may bind and separate. PathFiles are designed to create a size 20 Glide Path more…. However, being Rotary NiTi themselves, they need their own Glide Path, albeit a narrow one !
Always negotiate canal up to a size 10 Hand File before using PathFiles.
National Differences
In the UK, all endo files are single-patient use by law, so problems with separation (fracture) are rare. Outside the UK, they may be used many times, so separation (due to work-hardening) is a bigger problem.
How large should the Glide Path be?
A Protaper Shaper File will eventually separate if taken many times down canals with an inadequate glide path (See references at page bottom). Multiple-use is of course not a problem in the UK as they are only used once. Outside the UK, it is recommended that the Glide Path should be size 20, to prevent separation.
Dentaljuce recommend that:
• If using Hand Files only, and single-use files, the Glide Path should be prepared to a loose size 15. more…
• If using PathFiles, go up to size 19 (P3). They are flexible enough to go round the curves nicely, without transportation or ledging.
Easy Canal - i.e. Size 15 file goes to length
Just the Size 3 (0.19) PathFile is needed.
Normal Canal
1. Establish Patency with size 8, then 10 Hand Files.
2. Create glide path with Pathfiles 1, 2, 3 (.13, .16, .19) to 0.0 more…. (But it is also OK to go to +1.0, to maintain apical patency.)
Tight Canal
1. Explore with size 8, then 10 Hand Files. (May not reach length.)
2. Step Back with PathFiles 1, 2, 3 (.13, .16, .19) at 1mm increments from the size 10 length.
3. Use Protaper S1 to length of P3. This will improve access.
4. Retry 08, 10 Hand Files to length.
5. Proceed with Pathfiles as per normal canal
After Pathfiles have created Glide Path:
Establish EAL length (0.0).
Confirm glide path with P1, P2, P3.
References Click here
J Endod. 2004 Apr;30(4):228-30.
Influence of manual preflaring and torque on the failure rate of ProTaper rotary instruments.
Berutti E, Negro AR, Lendini M, Pasqualini D. Department of Endodontics, School of Dentistry, Turin University, Turin, Italy.
Abstract
We evaluated the influence of manual preflaring and torque on the failure rate of rotary nickel-titanium ProTaper instruments Shaping 1 (S1), Shaping 2 (S2), Finishing 1 (F1), and Finishing 2 (F2). These factors were evaluated using an in vitro method by calculating the mean number of Endo-Training-Blocks shaped before file breakage under different conditions.
Group A (S1 on simulators with no preflaring) shaped 10 blocks before failure, group B (S1 on manually preflared simulators) shaped 59 blocks (p<0.01 versus group A), group C (S2 with low torque) shaped 28 blocks, group D (S2 with high torque) shaped 48 blocks (p<0.01 versus group C), group E (F1 with low torque) shaped eight blocks, group F (F1 with high torque) shaped 23 blocks (p<0.01 versus group E), group G (F2 with low torque) shaped four blocks, and group H (F2 with high torque) shaped 11 blocks (p<0.01 versus group G).
Manual preflaring creates a glide path for the instrument tip and is a major determinant in reducing the failure rate of these rotary nickel-titanium files. All instruments worked better at high torque.
J Endod. 2009 Mar;35(3):408-12.
Use of nickel-titanium rotary PathFile to create the glide path: comparison with manual preflaring in simulated root canals.
Berutti E, Cantatore G, Castellucci A, Chiandussi G, Pera F, Migliaretti G, Pasqualini D. Department of Endodontics, School of Dentistry, University of Turin, Turin, Italy.
Erratum in: J Endod. 2009 Nov;35(11):1606.
Abstract
The study compared changes to canal curvature and incidence of canal aberrations after preflaring with hand K-files or with nickel-titanium rotary PathFile in S-shape Endo Training Blocks. The influence of the operator's expertise was also investigated. One hundred training blocks were colored with ink, and preinstrumentation images were acquired digitally. Preflaring was performed by an endodontist with PathFile (group 1) and hand stainless steel K-files #10-15-20 (group 2); an inexpert clinician performed preflaring with PathFile (group 3) and hand stainless steel K-files (group 4). Preinstrumentation and postinstrumentation images were superimposed to evaluate the outcomes investigated. Differences in canal curvature modification and incidence of canal aberration were analyzed with the Kruskall-Wallis plus post hoc tests and by the Monte Carlo method, respectively, (P < .05). The PathFile groups demonstrated significantly less modification of curvature (P < .001) and fewer canal aberrations (P < .001).
No expertise-related difference was found within instrument groups (P > .05), whereas the inexpert clinician produced more conservative shaping with Pathfiles than did the expert with manual preflaring (P < .01).