Effect of Intermediate Flush Using Different Devices to Prevent Chemical Smear Layer Formation

Area of Science:

• Endodontics
• Dental Materials Science
• Biomaterials

Background:

• Chemical smear layer (CSL) formation is a significant challenge in root canal therapy.
• Effective CSL removal is crucial for successful endodontic treatment and long-term prognosis.
• Current irrigation techniques may have limitations in completely eliminating CSL.

Purpose of the Study:

• To compare the efficacy of intermediate flushing with distilled water using conventional irrigation, EndoVac microcannula, or the Self-Adjusting File (SAF) system in preventing CSL formation.
• To evaluate the impact of different irrigation delivery methods on CSL reduction throughout the root canal.
• To determine the optimal irrigation protocol for minimizing CSL during chemomechanical preparation.

Main Methods:

• Thirty human premolars underwent root canal preparation using the Reciproc system and 5.25% sodium hypochlorite.
• Samples were divided into three groups (n=10) for intermediate flushing with distilled water via conventional irrigation, EndoVac, or SAF.
• Scanning electron microscopy (SEM) was used to assess CSL presence and severity across coronal, middle, and apical thirds.

Main Results:

• The SAF system demonstrated significantly less CSL formation compared to conventional irrigation and EndoVac (p<0.05).
• Conventional irrigation and EndoVac showed reduced CSL in coronal and middle thirds versus the apical third (p<0.05).
• No significant difference in CSL was observed among root canal thirds when using the SAF system (p>0.05).

Conclusions:

• Intermediate flushing with distilled water delivered by the SAF system is more effective in reducing CSL formation during chemomechanical preparation.
• The SAF system offers a more consistent CSL removal throughout the entire root canal length.
• SAF irrigation protocols represent an advancement in achieving cleaner root canal systems.