Present status and future directions: Canal shaping

Abstract

This narrative review will focus on the evolution, present and future of engine-driven root canal preparation. Root canal preparation changed drastically when Walia in 1988 introduced the use of nickel-titanium (NiTi) alloys in Endodontics. In 2013, five generations of NiTi endodontic instruments had been established based on their metallurgical, mechanical properties and design features. Since then, manufacturers have been introducing further major changes in instrument design and characteristics that have not been translated in new recognized generations of instruments. In general, those changes have demonstrated enhanced instrument properties, but it is not clear yet if all those improvements are directly translated to an improvement in clinical success. This narrative review attempts to address the present status of engine-driven instruments in terms of both evidence from laboratory-based studies and clinical data, to identify potential further generations of instruments, and last to anticipate future directions for research and development.

Advancing Nitinol: From heat treatment to surface functionalization for nickel–titanium (NiTi) instruments in endodontics

“…The application of NiTi in dentistry and specifically endodontics has been reviewed before, detailing metallurgical properties of the alloy, its’ structure, martensitic transformation ability and its evolutionary design [ 11 , 12 , [23] , [24] , [25] ]. NiTi alloys used in endodontic instruments contain approximately 56% (wt.)…”

Present status and future directions: vertical root fractures in root filled teeth

“…Furthermore, it has been reported that reciprocating single file systems are more likely to induce dentinal microcracks than continuous rotation file system (Bürklein et al, 2013). However, the results of ex vivo studies, as discussed previously, have been questioned, due to the presence of pre‐existing cracks in the sample selection (Arias & Peters, 2022; De‐Deus et al, 2014). The results of cadaver studies do not show any causal relationship between root canal shaping and the development of dentinal microcracks (Arias et al, 2014; Bahrami et al, 2017), and these results should be considered as more relevant due to absence of pre‐existing cracks (Versiani et al, 2021).…”

A Multimethod Assessment of a New Customized Heat-Treated Nickel–Titanium Rotary File System

“…The technology behind the metallurgy of nickel–titanium (NiTi) alloys allowed for the development of new rotary endodontic files with a variety of designs and improved efficiency and safety [ 1 ], aiming to reduce iatrogenic mishaps, such as deviation or perforation [ 2 ]. Currently, shaping procedures using NiTi rotary instruments are more predictable and easier when compared to manual preparation with stainless-steel files [ 1 , 2 ].…”

“…The technology behind the metallurgy of nickel–titanium (NiTi) alloys allowed for the development of new rotary endodontic files with a variety of designs and improved efficiency and safety [ 1 ], aiming to reduce iatrogenic mishaps, such as deviation or perforation [ 2 ]. Currently, shaping procedures using NiTi rotary instruments are more predictable and easier when compared to manual preparation with stainless-steel files [ 1 , 2 ]. The NiTi alloys used to produce endodontic instruments have an almost equiatomic ratio of nickel and titanium elements [ 3 , 4 ] and may have three microstructural phases, namely austenite, R-phase, and martensite, responsible for their mechanical behavior [ 3 , 5 ].…”