Denflex Co., Ltd. · Seoul, Korea

Spring Endo File

Innovative Technology for Safety

A heat-treated NiTi rotary file engineered with a unique spring structure on the shaft — minimizing file fracture and maximizing safety throughout root canal treatment.

Denflex Spring Endo File — NiTi rotary file with spring shaft bending into multiple positions
×1.85
Flexibility
×1.21
Fracture Resistance
50–60°
Full Torque When Bent
NiTi
Heat-Treated
23/25
mm Lengths
6/pk
Files per Package
The Spring Structure

Safety, Engineered Into the Shaft

Conventional NiTi files fracture most often at the shaft. The Spring Endo File introduces a machined spring section that absorbs and distributes load — fundamentally changing how the file behaves under stress.

SAFE

The spring structure minimizes the possibility of fracture inside the root canal. Load is distributed to the spring, and if overloaded the spring area fractures first — making the file far easier to retrieve.

EFFICIENT

Spring structure plus heat treatment improves cutting power through micro-vibration. 100% rotational torque is delivered even when the spring is bent 50–60°. Increased durability means more uses per file.

COMFORTABLE

The flexible spring makes treatment comfortable for both patient and dentist — easier for patients who cannot open wide, and no need to excessively remove tooth structure when the canal is off the central axis.

Four Spring Endo Files showing the flexible spring necks bending under load
Proven Performance

Measurably More Flexible. Measurably Stronger.

Independent mechanical testing on a 25mm / #25 Spring Endo File quantifies the advantage of spring machining on the file shaft.

Unmatched Flexibility

Bending Stiffness (N) — lower is more flexible
×1.85 more flexible
52 N
Non-Spring
7 N
Spring

85% greater flexibility than non-spring products — exceptionally resistant to fracture, allowing appropriate bending under lateral forces such as a brushing motion.

Strong Resistance to Fracture

Number of Cycles to Fracture (NCF) — higher is stronger
×1.21 more resistant
~1,340
Non-Spring
~1,620
Spring

Superior fatigue fracture resistance in repeated testing within a curved root canal — a clear improvement in the ability to withstand fracture compared to non-spring products.

* Sangmi Ahn, Jung-Hong Ha, Sang Won Kwak, and Hyeon-Cheol Kim. Advancement of Mechanical Properties of Nickel-Titanium Rotary Endodontic Instruments by Spring Machining on the File Shaft. Materials 2020, 13, 5246. Bending-stiffness and NCF figures based on Denflex internal testing using a 25mm / #25 Spring Endo File.

In the Root Canal

Built for the Curves of Real Anatomy

The spring neck flexes with the natural curvature of the canal while still transmitting full rotational torque to the cutting tip — negotiating curves that would stress and fracture a rigid file.

Cross-section render of the Spring Endo File flexing inside a curved root canal
Convex Triangular Cross-Section Micro-Vibration Cutting Shape-Memory NiTi

Flexes With the Canal

The spring section bends to follow canal curvature, reducing transportation and keeping the file centered — even in sharply curved canals.

Full Torque, Even Bent

100% rotational torque reaches the tip even when the spring is bent 50–60°, so cutting efficiency is maintained around the curve.

Heat-Treated Memory

Heat-treated files behave as a shape-memory alloy — bent files return to their original shape when warmed with hot water or a dryer.

Product Reference

Spring Endo File Line-up

Heat-treated NiTi endodontic files in 23mm and 25mm lengths, ISO sizes from glide-path to #50. Available in Forward (DFS) and Reverse (DFSR) rotation. Each size packaged 6 files per box.

The full Spring Endo File line-up, color-coded by ISO size
ISO SizeColor23mm25mm
PATH (Glide)White✓ Forward✓ Forward
#10Purple✓ F / R✓ F / R
#15White✓ F / R✓ F / R
#20Yellow✓ F / R✓ F / R
#25Red✓ F / R✓ F / R
#30Blue✓ F / R✓ F / R
#40Black✓ F / R
#50Yellow✓ F / R

Product Code Reference

Codes follow the pattern SFTG6HL{length}#{size}{F/R}-{finish}. Each size is offered in -S (standard pseudoelastic NiTi) and -B (heat-treated shape-memory) finishes.

Size23mm Forward23mm Reverse25mm Forward25mm Reverse
PATHSFPATHHL23#00FSFPATHHL25#00F
#10SFTG6HL23#10FSFTG6HL23#10RSFTG6HL25#10FSFTG6HL25#10R
#15SFTG6HL23#15FSFTG6HL23#15RSFTG6HL25#15FSFTG6HL25#15R
#20SFTG6HL23#20FSFTG6HL23#20RSFTG6HL25#20FSFTG6HL25#20R
#25SFTG6HL23#25FSFTG6HL23#25RSFTG6HL25#25FSFTG6HL25#25R
#30SFTG6HL23#30FSFTG6HL23#30RSFTG6HL25#30FSFTG6HL25#30R
#40SFTG6HL25#40FSFTG6HL25#40R
#50SFTG6HL25#50FSFTG6HL25#50R
Clinical Guidance

Tips for Using

Get the most from the spring structure. Recommended settings and handling for safe, efficient root canal preparation.

01 · START

Position on the Orifice, Then Rotate

Place the tip on the orifice before rotating. #10 or #15 files are recommended to first locate the orifice in rotation.

02 · SETTINGS

RPM 300–450 · Torque 1.0–2.0 N·m

Best cutting force range. If cutting power feels insufficient, raise the RPM or torque by one level.

03 · ROTATION

DFS Clockwise · DFSR Counter-Clockwise

Rotate DFS (Forward) files clockwise and DFSR (Reverse) files counter-clockwise.

04 · PRESSURE

No Lateral or Downward Pressure

Do not apply lateral or downward pressure while the file is rotating in the root canal.

05 · FILING

Lift Slightly While Filing

When filing in the canal, lift the file slightly toward the top for better cutting performance.

06 · ORIFICE

Expand the Orifice First

Used without orifice expansion, the tip 7–8mm can be forced by the canal — even a new file may break immediately.

07 · MAINTENANCE

Clear Cutting Residue

Remove the file periodically and clear cutting residue from the blade to maintain stable cutting performance.

08 · TESTING

Pre-Op Test on Natural Teeth Only

Administer pre-operational tests only on natural teeth. Do not test on a resin block.

09 · MATERIAL

Heat to Restore Shape

Heat-treated (shape-memory) files return to their original shape when warmed with hot water or a dryer.

Spring Endo File Hi Plus — bendable shaft holding a curved shape
New · Contact Denflex

Spring Endo File Hi Plus

An optimized file for treating patients with limited mouth opening and maxillary molars. The shaft can be bent and moved into the oral cavity while maintaining the bent shape formed outside the mouth.

Pre-Bendable Shaft

Bend the shaft outside the mouth and bring it to position while it holds the curve — ideal for hard-to-reach posterior access.

Excellent in Curved Canals

Delivers excellent performance in curved root canals without breaking the file.

Ask About Hi Plus

Bring the Spring Endo File to Your Practice

Request samples, pricing, or a clinical consultation from Digiscope — your authorized partner for Denflex in the Philippines.

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© 2026 Digiscope. Authorized distributor for licensed dental professionals in the Philippines. Spring Endo File™ is a trademark of Denflex Co., Ltd., Seoul, Republic of Korea.