In Vitro Evaluation of the Biolase ER,CR:YSGG Side-Firing Tip For Bacterial Biofilm Reduction and Smear Layer Removal in Root-End Cavity Preparation

Objective Persistent endodontic infections are frequently associated with residual bacterial biofilm and smear layer that may remain after conventional chemomechanical debridement and ultrasonic root-end preparation, contributing to post-treatment apical periodontitis and compromising root-end surface cleanliness. The objective of this in vitro study was to evaluate the antimicrobial efficacy and smear layer removal capacity of a Biolase Waterlase iPlus Er,Cr:YSGG laser equipped with a side-firing tip on Enterococcus faecalis biofilm-contaminated retroprepared root-end surfaces. Methods Twenty-five extracted permanent maxillary central incisors were prepared, obturated, apically resected by 3 mm, and retroprepared to a standardized 3 mm depth. Specimens were randomly allocated into three groups: laser-treated experimental specimens inoculated with E. faecalis biofilm (n = 10), inoculated untreated negative controls (n = 10), and uninoculated controls (n = 5). Experimental and negative control specimens were inoculated with E. faecalis for 7 days. The experimental group received Er,Cr:YSGG irradiation using a side-firing tip in implant decontamination mode at 1.5 W, 30 Hz, 40% air, and 50% water for two 1-minute cycles. Residual viable bacteria were sampled, serially diluted, plated, incubated, and quantified as colony forming units per milliliter. Log-transformed data were analyzed using one-way ANOVA, and representative specimens were examined by scanning electron microscopy. Results The inoculated untreated control group demonstrated the highest bacterial burden, with a geometric mean of 198,898 CFU/mL. The laser-treated group showed a significantly lower geometric mean of 53,393 CFU/mL, representing a 3.7-fold reduction compared with the negative control group (p = 0.009). No statistically significant difference was detected between the laser-treated and uninoculated control groups (p = 0.479). SEM observations supported the quantitative findings, demonstrating reduced biofilm and smear layer coverage with exposed dentinal tubules on the laser-treated surface. Conclusion Within the limitations of this in vitro model, Er,Cr:YSGG laser irradiation delivered through a side-firing tip significantly reduced recoverable E. faecalis biofilm on retroprepared root-end surfaces. Qualitative SEM findings demonstrated less residual biofilm and smear layer coverage on the laser-treated surface compared with the untreated control, supporting the microbiologic results. These findings suggest that side-firing Er,Cr:YSGG laser irradiation may represent a promising adjunct for root-end decontamination in endodontic microsurgery.

Author dc:creator

• Morris, Logan Samuel

Advisor dc:contributor.advisor

• Karunanayake, Glen

• Endodontic microsurgery
• Er,Cr:YSGG laser
• side-firing tip
• Enterococcus faecalis
• root-end disinfection
• biofilm
• scanning electron microscopy

Language dc:language.iso

en_US

Handle dc:identifier.uri

https://hdl.handle.net/1805/56848

OAI identifier oai:identifier

oai:scholarworks.indianapolis.iu.edu:1805/56848