Study warns of safety risks linked to counterfeit and replica endodontic files

The review, conducted by researchers at universities in Australia, Brazil and the US, evaluated the available evidence comparing the performance of imitation endodontic systems with that of original products. The authors noted that great demand for NiTi instruments, combined with their relatively high cost, has helped create a market for cheaper alternatives.

The researchers distinguished between counterfeit files, which are deliberately misrepresented and packaged to imitate established brands, and replica systems, which mimic existing designs but are legally manufactured and sold in some markets. Their analysis included 17 in vitro studies assessing mechanical behaviour, metallurgical characteristics, instrument design and surface quality.

Counterfeit instruments show consistent mechanical weaknesses

Across multiple laboratory investigations, counterfeit files demonstrated a clear and recurring pattern of inferior performance. The researchers reported substantial differences in geometry, manufacturing precision and metallurgical properties compared with genuine instruments. These variations were associated with poorer mechanical behaviour. In particular, counterfeit files repeatedly showed lower cyclic fatigue resistance. Several studies also identified altered bending behaviour, such as reduced flexibility, often linked to differences in alloy processing or heat treatment.

Surface quality emerged as another major point of distinction. Counterfeit instruments frequently exhibited machining grooves, irregular finishing and other surface defects that can act as stress concentration points and accelerate crack initiation.

Variations in microhardness, phase transformation behaviour and, in some systems, alloy composition further confirmed that many counterfeit files may be visual copies, but are produced using different manufacturing protocols.

Replica systems deliver mixed and inconsistent results

Findings for replica systems were more heterogeneous. Some studies reported mechanical behaviour comparable to that of the original products they emulate, including similar fatigue resistance or shaping performance. In isolated cases, certain parameters were even better than those of the genuine instruments.

However, this comparability was not consistent across studies. Other investigations reported reduced torsional resistance, altered flexibility or differences in phase transformation behaviour. These variations appear to reflect differences in alloy processing, heat treatment and surface finishing. According to the authors, such manufacturing variability may produce inconsistent mechanical profiles and could potentially affect reliability during clinical use.

A lack of clinical evidence

Despite a growing body of laboratory research, the review identified a major gap in clinical evidence. No clinical studies evaluating treatment outcomes or complication rates associated with replica or counterfeit files were identified. The authors noted that controlled clinical evaluation of counterfeit instruments would raise significant ethical concerns, so assessment must be inferred from laboratory findings. This lack of clinical data makes it difficult to quantify real-world risks, reinforcing the need for precautionary approaches in procurement and use of endodontic files.

Replica instruments are reportedly used widely by clinicians internationally despite limited clinical validation. Because the use of replica files may be acceptable under specific conditions, such as in resource-limited settings, rigorous clinical investigations are needed for replica files, the authors said. In this regard, they also highlighted the absence of international regulatory frameworks requiring standardised quality control for NiTi rotary or reciprocating systems and warned that practitioners may unknowingly use devices that have not undergone robust scientific evaluation.

Implications for regulation and clinical practice

The researchers called for stronger regulatory oversight of counterfeit dental devices and more comprehensive evaluation of replica systems. Because quality control requirements vary between jurisdictions, responsibility for identifying potentially unreliable products may fall partly on clinicians and purchasers.

For practitioners, the findings underscore the importance of sourcing endodontic instruments through verified supply chains and exercising caution when encountering unusually low-cost products or packaging inconsistencies. The authors suggested that greater awareness and careful procurement practices could help reduce risks associated with counterfeit dental devices.

The authors concluded that counterfeit NiTi endodontic files consistently demonstrated compromised mechanical performance and may represent a significant patient safety concern. Since such products are becoming more widely available and regulatory oversight is uneven in some markets, further research and policy action are needed to safeguard clinical practice.

The study, titled “The hidden dangers of counterfeit and replica-like endodontic files: A scoping review of current evidence”, was published online on 19 December 2025 in the Australian Dental Journal, ahead of inclusion in an issue.

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