# HyFlex® CM

> Controlled Memory

- **Manufacturer:** Coltene
- **Motion:** Continuous Rotation
- **Alloy:** CM-Wire (Controlled Memory NiTi)
- **Key feature:** Pre-bendable like stainless steel with enhanced cyclic fatigue resistance vs conventional NiTi (manufacturer reports up to 300%, in-house bench data)

## Specifications

| File | Tip (mm) | Taper | Length | Cross-section | Motion | Speed (rpm) | Torque | Role |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Orifice Opener 25/.08 | 0.25 | 8% | 19mm | Triangular / Quadrangular (mixed design) | Continuous Rotation | 500 | 2.5 Ncm | shaping |
| 20/.04 | 0.20 | 4% | 21mm, 25mm, 31mm | Triangular / Quadrangular (mixed design) | Continuous Rotation | 500 | 2.5 Ncm | — |
| 25/.04 | 0.25 | 4% | 21mm, 25mm, 31mm | Triangular / Quadrangular (mixed design) | Continuous Rotation | 500 | 2.5 Ncm | — |
| 20/.06 | 0.20 | 6% | 21mm, 25mm, 31mm | Triangular / Quadrangular (mixed design) | Continuous Rotation | 500 | 2.5 Ncm | — |
| 30/.04 | 0.30 | 4% | 21mm, 25mm, 31mm | Triangular / Quadrangular (mixed design) | Continuous Rotation | 500 | 2.5 Ncm | — |
| 40/.04 | 0.40 | 4% | 21mm, 25mm, 31mm | Triangular / Quadrangular (mixed design) | Continuous Rotation | 500 | 2.5 Ncm | finishing |

## Protocol

### Glide Path

1. **Establish Access & Glide Path** — After straight-line coronal access, establish an apical glide path to at least a #20/.02 hand file. Ensure the canal is irrigated (NaOCl) and lubricated before instrumentation.
   - A mechanical glide path file (e.g. HyFlex GPF) may be used as an alternative to hand files
   - Ensure the canal always remains irrigated and lubricated
2. **Coronal Opening** — Use the Orifice Opener (25/.08) to create coronal flare. Advance slowly with a pecking motion without pressure. Stop when resistance is felt. Check patency with a #20/.02 hand file. Irrigate. _(File: Orifice Opener 25/.08 · 500 RPM · 2.5 Ncm)_
   - In large canals where this file reaches working length, you may skip directly to Step 4 (20/.06)
   - Do not force the file apically — let it advance passively

### Shaping

1. **Step 2 — Apical Enlargement (20/.04)** — Use the 20/.04 file to working length. Advance slowly with a pecking motion without pressure. Check patency with a #20 hand file. Irrigate. _(File: 20/.04 · 500 RPM · 2.5 Ncm)_
   - Clean the file flutes after every insertion
   - If resistance is felt, withdraw and re-irrigate before re-entering
2. **Step 3 — Apical Enlargement (25/.04)** — Use the 25/.04 file to working length. If resistance is encountered, return to the previous file. Check patency. Irrigate. _(File: 25/.04 · 500 RPM · 2.5 Ncm)_
   - Recapitulate with a hand file between each rotary file change
3. **Step 4 — Middle Third Shaping (20/.06)** — Use the 20/.06 file to shape the middle section of the canal. This file can also be taken to working length. Pecking motion without pressure. Check patency. Irrigate. _(File: 20/.06 · 500 RPM · 2.5 Ncm)_
   - The 6% taper creates a wider coronal flare for improved irrigation access
4. **Step 5 — Apical Enlargement (30/.04)** — Use the 30/.04 file to enlarge the apical section to working length. Pecking motion without pressure. Check patency. Irrigate. _(File: 30/.04 · 500 RPM · 2.5 Ncm)_

### Finishing

1. **Step 6 — Final Preparation (40/.04)** — Use the 40/.04 file for final apical preparation to working length. Pecking motion without pressure. Check patency. Irrigate. _(File: 40/.04 · 500 RPM · 2.5 Ncm)_
   - Verify final preparation size with a #40 hand file at working length
   - Proceed with final irrigation protocol before obturation
2. **Inspect and Reprocess** — After use, clean and steam sterilize files (134°C, shortest hold time: 3 min per 2025 IFU). CM-Wire shape regenerates during autoclaving. Inspect spirals after autoclaving — if multiple spirals remain lengthened or do not return to original shape, discard the file.
   - Spiral lengthening during use is normal — it is a safety feature that prevents binding
   - Shape regeneration occurs during steam sterilization (per IFU)
   - ⚠ If spirals rewind in the opposite direction during use, the file is plastically deformed and will not regain its shape — discard immediately
   - ⚠ If spirals remain lengthened after autoclaving, discard the file

## Clinical Tips

- CM-Wire has no shape memory at room temperature — files can be pre-bent like stainless steel to follow abrupt curvatures
- Spiral lengthening under stress is a built-in safety feature that prevents wall binding and reduces fracture risk
- Shape regenerates during autoclaving — visual inspection after autoclaving serves as a discard indicator
- All files use the same motor settings: 500 RPM and 2.5 Ncm (EU IFU; US IFU specifies 2.4 Ncm)
- Files may arrive slightly bent due to CM properties — correct by hand before use
- A hybrid technique combining .04 and .06 tapers is the IFU-recommended approach

## Warnings

- If spirals rewind in the opposite direction during use, the file is plastically deformed — discard immediately
- If spirals remain lengthened after autoclaving, the file must be discarded
- Inspect files before and after every use for visible changes in material or shape
- Do not use on patients with known nickel or titanium allergy (per 2025 IFU)
- Follow IFU reprocessing instructions — condition-based reuse, no fixed maximum cycle count

## Best for

- curved canals requiring pre-bent files
- anatomical shaping with multiple sizing options
- reusable with autoclave regeneration

## Technical profile

- **Category:** multi-file-rotary
- **Heat treatment:** CM-Wire — CM-Wire — thermomechanically processed NiTi in a predominantly martensitic phase at room temperature, eliminating shape memory for pre-bendability
- **Manufacturing method:** ground
- **Pre-bendable:** yes
- **Reuse:** Reusable (limited)
- **Motor:** any-rotary
- **Glide path requirement:** optional
- **Canal suitability:** Curvature: mild, moderate, severe; Canal size: narrow, normal, wide; Calcified canals: no; Retreatment: no; Conservative access: no
- **Content revision:** 2026-02-15

## FAQ

**What alloy is HyFlex CM made from?**

HyFlex® CM is manufactured from CM-Wire (Controlled Memory NiTi) with cm-wire heat treatment.

**How many files are in the HyFlex CM sequence?**

The HyFlex® CM system includes 6 files: Orifice Opener 25/.08, 20/.04, 25/.04, 20/.06, 30/.04, 40/.04.

**What motion type does HyFlex CM use?**

HyFlex® CM uses continuous rotation motion.

**What cases is HyFlex CM best for?**

HyFlex® CM is best suited for: curved canals requiring pre-bent files, anatomical shaping with multiple sizing options, reusable with autoclave regeneration.

**What speed and torque settings are recommended for HyFlex CM?**

Recommended settings: 500 RPM and 2.5 Ncm across the file sequence (refer to official DFU for full per-file parameters).

## References

- [Manufacturer instructions for use (DFU/IFU)](https://media.coltene.com/EN/GB/media/DOC_IFU_30001992-03-25-HyFlex-CM-A4_IND.pdf?sprache=EN)

## Related

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_Educational reference for dental professionals. Always confirm settings against the official manufacturer instructions for use before clinical procedures._