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Quasistatic Mechanical Testing for Computer-Aided Design and Manufacturing Occlusal Veneers Cemented to Milled Dentin Analog Material
Published on: December 20, 2024
An Integrated Chemical, Molecular, Elemental, Structural, and Mechanical Analysis of Er;Cr:YSGG versus Diode
Neha N Rathod1, Aparna Mohan1, Veronica Kindaro2
1Saveetha Dental College and Hospitals, Saveetha University, Chennai, Tamil Nadu, India.
Introduction:
Laser activated irrigation (LAI) has enhanced the cleaning and disinfection of root canals. However, limited evidence exists regarding its effects on dentin's structural integrity. Although proven to enhance cleaning and disinfection results, it was anticipated that LAI use may alter the root dentin surface due to thermal effects.
Methods:
Forty-two single-rooted human premolars were instrumented and randomly divided into 3 groups: A) control group (n = 14) no laser treatment; B) irrigant activation using diode laser (980 nm, 10 Hz, 200 μm, 21 mm) (n = 14); and C) irrigant activation using Er,Cr:YSGG laser (2940 nm, 25 mJ, 10 Hz, 60 μs 200 μm, 21 mm) (n = 14). The root canal dentin samples were subjected to scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy (FTIR), and nanoindentation analysis. Sample size was calculated using G∗Power, and data were statistically analyzed using one-way ANOVA and post hoc Tukey tests through SPSS software (IBM Corp. IBM SPSS Statistics for Windows, Version 26.0. Armonk, NY).
Results:
FTIR analysis of diode-treated dentin revealed structural degradation with new hydroxyl groups (3829.74, 3744.47 cm-1) and strong carbonyl peak (1741.30 cm-1). FTIR compositional analysis showed destruction of amide (collagen), phosphate, and carbonate contents in laser groups. Elemental analysis showed significantly increased Ca and P peaks. Structural examination revealed excessive thermal-stress-induced cracking in the diode group and moderate cracking in Er,Cr:YSGG group. Mean hardness (HIT, HVIT) and elastic modulus differed significantly between control and both laser groups. Traditional root canal disinfection produced minimal structural damage across all analyses.
Conclusions:
LAI significantly altered the tested properties of root dentin. Er,Cr:YSGG showed comparatively lesser structural damage than diode laser based irrigant activation.
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