Managing severely curved canal with Fanta AF F-One file

A 26 years old female presented seeking restoration of her badly Brocken down UL6. Clinically, there were gingival and pulpal polyps. Tooth was negative to percussion.
Diagnosis: Asymptomatic irreversible pulpitis.
Treatment plan: Root canal treatment of UL6 and restoring the tooth to function.

Fig. 01
Initial clinical situation showing badly Brocken down UL6 with gingival and pulpal polyps.

Fig. 02
Initial radiograph showing a severely curved MB root

Fig. 03
Initial bite-wing radiograph showing the level of the remaining sound tooth structure in accordance to the level of the crestal bone level.

Fig. 04
Using diode laser to remove the gingival polyp.

Fig. 05
Isolation with rubber dam using Henry Schein winged clamp size 14A placed on UL7, to give more room for working field.

Fig. 06
Removing pulpal polyp using orifice opener and copious irrigation of NaOCl 3%

Fig. 7
Removing remaining calcified pulp tissue using Satelec ultrasonic tip

Fig. 08
Conventional matrix band and retainer to build-up missing walls and converted to class 1 cavity.

Fig. 09
Cavity been converted to class 1 with composite resin.

Fig. 10
Sagittal views showing the severity of curvature of MB root. The views also showing no separate MB2 canal; the MB canal is type 3 vertucci (1-2-1)

Fig. 11
Coronal views showing the horizontal extent of the MB root

Fig. 12
Pre-curving the apical 2mm of K file 10 to easily negotiate the canal with gentle watch-winding motion to get a patent pathway for rotary files.

Fig. 13
Working length been determined using E-Pex apex locator.

Fig. 14
Pre-curving F-One file #25/0.04. It has been used as single rotary file at speed 500 RPM which easily went through the curved MB canal. DB and P canal were also prepared using F- One #25/0.04.

Fig. 15
Irrigation with NaOCl 3%, EDTA 18%. Activation:
For MB canal; PUI by Ultra X above the curvature, and EDDY flexible sonic tips beyond the curvature.
For DB and P canals, PUI by Ultra X.

Fig. 16
Tooth is ready for obturation.

Fig. 17
Obturation for MB canal done with S obturation of warm Gutta percha. Obturation for DB and P canals was with continuous wave compaction (CWC).

Fig. 18
Final radiograph with composite restoration.

Fig. 19
Tooth been prepared for E-max crown, and ready to receive the crown after isolation.

Fig. 20
Final restoration of the tooth with E-max crown.

Discussion:
AF F-One file (Shanghai Fanta Dental Materials Co., LTD) is an excellent file that can deal with even the most difficult situations; It has a unique cross section design with two active cutting points (Fig. 21) with a flat side-cut design (Fig. 22). This unique design provides more cutting efficiency, in which the debris can be swept from flutes to the safe- side relief area through vertical blades, and then outside the canal (Fig. 22), so more debris removal during instrumentation and less debris accumulation around the file. This unique design promotes more efficient cutting and less stress subjected on the file, so decreasing the chance of file separation. The flat side-cut design also offers a more room for irrigation solutions during instrumentation; less surface area contact with canal walls, which offers less stress subjected on the file. The good thing about the that flat side-cut design is not deeply cut in the file, this increases the the flexibility of the file without compromising file strength. AF F-One file has non-cutting tip, which decreases the likelihood of iatrogenic complications like perforation, zipping, ledges, and canal transportation.

Fig. 21
Two active cutting points in AF F-One file.

Fig. 22
The unique safe side-cut design of AF F-One file.

According to the manufacturer, AF F-One file has 150% higher resistance to cyclic fatigue than AF blue S-One file (which is a single rotary file too) (Fig. 23). AF F-One file is made of AF-R wire (Fig. 24), which is a developed NiTi alloy with more flexibility; good shape memory; excellent mechanical properties; and good cutting efficiency.

Fig. 23
F-One is 150% higher resistance than AF blue S-One in cyclic fatigue. (http://fantadental.com/ col.jsp?id=127)

Fig. 24
AF F-One file is made of AF-R wire. (http://fantadental.com/ col.jsp?id=127)

F F-One file is a single rotary file system. After negotiating the canal with hand file K10,
you can proceed with F-One file with pecking motion (2-3mm depth) at speed of 500 RPM rotation and 2.6 N torque (as recommended by the manufacturer).

Conclusion:
The aim of Endodontics treatment is to prevent or cure Apical periodontitis (Ørstavik & Pitt Ford 2008). To achieve this goal, conventional Endodontic treatment is carried out through two important stages; chemo-mechanical debridement of the root canal system, and to obturate the disinfected root canal system with a well adapted root canal filling with hermetic seal.
Preparation of the root canal system (chemo-mechanical debridement) comprises of using special instruments (files and reamers), and special irrigation solutions. Mechanical
Fig. 24
AF F-One file is made of AF-R wire. (http://fantadental.com/ col.jsp?id=127)
debridement (instrumentation) consists the removal of the infected hard and soft tissues, shaping of the root canal(s) to improve access and delivery of the irrigating solutions, medicaments, and placement of the root canal filling (Schilder 1974). The instrument being used to prepare canal(s) should results a prepared canal that includes the original canal, apical constriction should be maintained, ends in an apical narrowing, and tapered from crown to apex (ESE 2006).
Managing curved canals may be quite difficult to and may leads to many iatrogenic complications especially file separation. These cases require good reading and interpretation of the pre-operative radiograph, to decide the how to approach these difficulties by using the best instrument, and to finish the root canal treatment successfully.
Bibliography:
• European Society of Endodontology (2006) Quality guidelines for endodontic treatment: consensus report of the European Society of Endodontology. International Endodontic Journal, 39(12),921-930.
• http://fantadental.com/col.jsp?id=127.
• Ørstavik D, Pitt Ford TR (2008) Apical Periodontitis: Microbial infection and host responses.
In: Orsta Ørstavik vik D and Pitt Ford TR, Essential Endodontology 2nd edition. Oxford:
Blackwell Science, 1-9.
• Schilder H (1974) Cleaning and shaping of the root canal. Dental Clinics of North America 18,
269-296.