This method, although not the term stepdown, was first suggested by Schilder in 1974, and the technique was described in detail by Goerig et al.2
It has been followed by other, similar techniques such as the double flared3
and the crown-down pressureless.4
The principle of these techniques is that the coronal aspect of the root canal is widened and cleaned before the apical part (Fig. 3). The obvious advantages of these methods over the stepback are as follows.
It permits straighter access to the apical region of the root canal.
It eliminates dentinal interferences found in the coronal two-thirds of the canal, allowing apical instrumentation to be accomplished quickly and efficiently.
The bulk of the pulp tissue debris and microorganisms are removed before apical instrumentation is commenced, which greatly reduces the risk of extruding material through the apical foramen and causing periapical inflammation. This should reduce the incidence of after-pain following preparation of the root canal.
The enlargement of the coronal portion first has several benefits. It allows better penetration of the irrigating solution to the entire root canal system and forms a reservoir of irrigant which is more readily replenished in the canal system. It also reduces the risk of compacting debris apically which may block the canal.
The stepdown technique is now the most widely used technique for canal preparation, and will be described later in this part.