Non–Contact Quantification of Debris and Biofilm in the Root Canal

Objectives: To quantify the amount of debris and biofilm remaining in simulated root canal system (RCS) following instrumentation with ProTaper Universal (PTN), ProTaper Next (PTN), and Revo-S (RS) rotary file systems using the optical coherence tomography (OCT).

Methods: Forty novel transparent models of simulated RCS with continuous isthmi were created using rapid prototyping technology. A 4-day old dual species biofilm was generated in each RCS using the constant depth film fermenter. Each group (n = 10) was prepared by a different file system whilst irrigating with 2 % CHX solution. One untreated group was used for validation. Cyclic OCT scans at 930-nm were arranged to show the differences throughout the root canal space in 3D levels following different treatments. Image stacks were co-registered with 3D Slicer software and manipulated by ImageJ software to segment and quantify the remaining debris and biofilm. Results were statistically analysed by LSD and Spearman’s correlation tests at p ≤ 0.05.

Results: The OCT method distinguished the debris and the biofilm throughout the RCS at less than 30-seconds. Positive correlations were reported between debris and biofilm that remained in the isthmus space following preparation. The RS treatment procedure left the least debris and biofilm compared to the other systems.

Conclusions: The OCT scanner is an effective and fast imaging tool to quantify debris and biofilm in simulated root canals. The RS system was more effective than PTU and PTN at removing debris and biofilm in this in vitro model.