National Dental Assisting Examining Board (NDAEB) Practice Exam

During an RCT procedure, how much are the canal walls widened by?

1. 1mm

2. 2mm

3. 3mm

4. No widening occurs

The correct answer is: No widening occurs

In a root canal treatment (RCT), the objective is to remove infected or damaged pulp tissue from the tooth while preserving as much of the tooth structure as possible. During the cleaning and shaping phase of the procedure, the instruments used (such as files and reamers) do create space within the canal, but it's important to note that the widening of the canal walls does not occur by a fixed measurement like 1mm, 2mm, or 3mm. Instead, the primary goal is to create a taper within the canal that facilitates optimal irrigation, disinfection, and filling of the canal after it has been cleaned. While the files may technically alter the shape of the canal, the widening is not standardized to a specific measurement, nor does it necessarily occur uniformly across all cases. Thus, the concept that there is no predetermined or consistent widening of the canal walls is accurate in the context of this question. Furthermore, the treatment aims to retain a tooth's structural integrity while preparing it for adequate filling with materials that promote healing and prevent re-infection. Therefore, claiming that no widening occurs aligns with the objectives of preserving the tooth's original structure while allowing for necessary cleaning and shaping during RCT.