Comparative Evaluation of Minimally Invasive and Conventional Access on The Biofilm Elimination of Enterococcus Faecalis From the Root Canal System

Abstract

Background: The access cavity is a fundamental step in endodontic treatment. Traditionally, it is performed by completely removing the pulp chamber and all its contents. Recently, the introduction of technologies such as the operating microscope, ultrasound, and Ni-Ti instrumentation systems has allowed this phase to be performed conservatively through minimal invasive access. However, further evidence is needed to determine whether these techniques allow complete elimination of microorganisms within the root canal system.

Objectives: The aim of this study was to evaluate the effects of minimally invasive access (MIA) compared with conventional access (CA) on the disinfection and elimination of biofilm Enterococcus faecalis in root canal therapy.

Methods: Forty-four first molars were selected and randomly divided in groups: MIA and CA (n= 15 each), positive control (n= 8), negative control (n= 6). After access cavity, the root canals were contaminated with E. faecalis for 30 days. Bacterial sampling was performed with sterile paper points before (S1) and after (S2) instrumentation with the TruNatomy system to quantify the bacterial load. Colony-forming units per milliliter (CFU/mL) and scanning electron microscopy (SEM) were used for bacterial reduction assessment and elimination of biofilm.  Statistical comparisons were conducted using Student’s t-test or Mann–Whitney U test, with significance set at 5%.

Results: Significant reductions in E. faecalis were observed in all groups, regardless of cavity design. However, the lowest bacterial reduction was found in the MIA group, while the CA group achieved the highest reduction.

Conclusions: Conventional access resulted in significantly better disinfection compared with minimally invasive access. These findings suggest that the design of the access cavity influences bacterial load reduction and biofilm elimination within root canals.

Keywords:

Bacterial reduction, biofilm elimination, minimally invasive access, conventional access, TruNatomy

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