Impacts of Conservative Endodontic Cavity on Root Canal Instrumentation Efficacy and Resistance to Fracture Assessed in Incisors, Premolars, and Molars

By Krishan R, Pague F, Ossareh A, Kishen A, Dao T, Friedman S

Date: 01/2014
Journal: JOE


  • Purpose: To assess the impact of Conservative Endodontic Cavity (CEC) in different tooth types regarding the proportion of the untouched canal wall area (UCW), volume of dentin removed (VDR) and load at fracture under loading.
  • N= 90 extracted human teeth  (30 incisors, 30 premolars, and 30 molars.) 


1.Of the instrumented teeth, half assigned to CEC, the other half to (TEC) access. 20 teeth\group, CEC and TEC, and (n = 10/group/type) were negative control.

2.Micro-CT imaging. Teeth were accessed and instrumented with WaveOne, 1.25 % NaOCl.

3.Post-op micro-CT imaging. 

4.The proportion of the Untouched Canal Wall (UCW) and Dentin Volume Removed (DVR) for each tooth type was analyzed. 

5.Teeth loaded in Instron Universal Testing machine to quantitate compressive fracture.

Most highlighted Results:

1.The mean proportion of the UCW was significantly higher in distal canals with CEC (52%) compared to TEC (36%)

2.VDR was statistically significantly smaller in the CEC group than in the TEC group for all tooth types.

3.In premolars and molars, the mean load at fracture for CEC was significantly higher than for TEC, and it did not differ significantly from intact teeth (negative control).

  1. in the TEC group, the load at fracture in premolars and molars was significantly lower than in intact controls. 

5.No WaveOne instrument fractures occurred. 

Clinical Significance:

  • CEC afforded conservation of coronal dentin in incisors, premolars, and molars and increased resistance to fracture in molars and premolars, but it compromised the efficacy of canal instrumentation in the distal canals of molars.