Comparative Analysis of Dentinal Crack Formation Following Root Canal Instrumentation with Hand K-Flex Files, ProTaper Next, and Self-adjusting Files

Abstract

Aim: To evaluate and compare in vitro the dentinal crack formation in root canal dentin after root canal instrumentation with hand K-Flex files, ProTaper Next, and self-adjusting engine-driven files. Materials and methods: Ninety-two human mandibular first molar teeth were randomly divided into four groups (n = 23) as per the instrumentation protocol: group I-unprepared teeth (control); group II-hand K-Flex files (Sybron Endo); group III-ProTaper Next X1 and X2 (Dentsply Maillefer); group IV-self-adjusting file (ReDent Nova, Israel). All the roots were sectioned perpendicular to the long axis of the tooth at 9 mm, 6 mm, and 3 mm from the apex and thereby obtaining sixty-nine samples, which were then subjected to a stereomicroscopic examination for detection of dentinal cracks. Statistical analyses were done using the Chi-square test with SPSS (version 19), and p value was set at p < 0.05. Results: Statistically significant differences were seen between the instrumented groups. No dentinal cracks were found in the unprepared roots and those prepared with hand K-Flex files (0/23). Self-adjusting-file-instrumented group showed significantly less incidence of crack formation when compared to the ProTaper Next group with p = 0.001. Conclusion: Self-adjusting file is an efficient engine-driven NiTi instrument for root canal instrumentation with the least occurrence of crack formation in the root canal dentin compared to the ProTaper Next system. Clinical significance: The introduction of NiTi rotary file systems has metamorphosed the endodontic treatment by their better cutting efficiency and cleaning potentiality. Yet, evidenced-based clinical studies are to be conducted on the incidence of microfractures that can lead to vertical root fractures, which will be produced irrespective of the motion kinematics and design feature and thereby compromising the clinical maintenance of the endodontically treated teeth.

Comparison of fracture resistance of teeth with prepared protaper next, protaper gold, and hyflex CM rotary files

“…Many studies have evaluated how rotating instrument systems affect dentinal cracks. [24][25][26][27] While Milani et al have argued that resistance to root fracture is more concise and clinically relevant than counting dentin cracks, El Nasr and Abd El Kader 28 stated that analysis of dentinal cracks is a good tool that can indicate root fracture. This study revealed differences in the fracture resistance between teeth prepared using three different instrumentation systems (p < 0.05).…”

“…Depending on the instrument geometries, dimensions, alloys, and forces, the risk or occurrence of dentin damage may vary between instrument systems.This study investigated the effect of different NiTi rotational systems on the tooth's ability to resist fracture after biomechanical preparation. Many studies have evaluated how rotating instrument systems affect dentinal cracks [24][25][26][27]. While Milani et al have argued that resistance to root fracture is more concise and clinically relevant than counting dentin cracks, El Nasr and Abd El Kader 28 stated that analysis of dentinal cracks is a good tool that can indicate root fracture.…”

The effect of endodontic instrumentation on fatigue, fracture load, and dentin crack formation in restored uniradicular teeth: in vitro study

“…Then, the preparation drill was coupled to a paralelometer, and the root was inserted into a PVC matrix (25 mm x 15 mm) filled with acrylic resin (JET, Clássico, Cotia, SP, Brazil), and the roots were inserted 12 mm into acrylic resin, having 2 mm that remained up. After the resin cure, roots were removed, and the aluminum foil was removed and replaced by silicone impression material (Perfil, Coltene, São Paulo, SP, Brazil) for periodontal ligament simulation [9].…”