Great progress has been made over the years in the technology of rotary nickel-titanium file systems. Nevertheless, both the oldest and the newest systems all use the same principle of a rotating blade with flutes, designed to carry off or contain the cut material and/or debris. While this concept may provide adequate results in narrow, straight canals with round cross sections, it has substantial limitations when oval or curved canals are concerned. Such canals are very common. The Self-Adjusting File (SAF) system is based on a new and different concept that is aimed at overcoming the limitations of current rotary file technology. This review aims to familiarise the reader with the new concept and technology of the SAF system and to individually discuss the major endodontic challenges that are yet to be conquered by rotary file technology. The ways by which the new SAF system overcomes these challenges will be explained, based on 32 research papers that were published over the past 3 years. A new concept for root canal cleaning and shaping will be presented and justified: the concept of 'minimally invasive endodontics', which has been made possible by the new SAF technology. Keywords: minimally invasive endodontics, NiTi Files, rotary files, SAF, Self-Adjusting File