Radiopacity quantification and spectroscopic characterization of OrthoMTA and RetroMTA

Area of Science:

• Materials Science
• Biomaterials Engineering
• Dental Materials Science

Background:

• Radiopacity is a critical property for dental materials, enabling visualization on radiographs.
• Accurate assessment of radiopacity is essential for material selection and clinical evaluation.
• Previous radiopacity data for OrthoMTA and RetroMTA were limited, necessitating further investigation.

Purpose of the Study:

• To investigate and compare the radiopacity performance of OrthoMTA and RetroMTA using modern imaging analysis and energy dispersive X-ray spectroscopy.
• To determine the elemental composition and major radiopacifiers in commercial hydraulic calcium silicate-based cements and a calcium hydroxide-based paste.
• To establish a reproducible method for quantifying radiodensity in digital X-ray data.

Main Methods:

• Utilized energy dispersive X-ray spectroscopy for elemental analysis of dental cements.
• Acquired radiographic image data following ISO 6876-2012 standards.
• Employed image analyzing software to measure mean grey values within defined regions of interest and created a calibration curve against aluminum (mm Al) equivalents.

Main Results:

• Elemental analysis identified key radiopacifiers: Bismuth (Bi) in OrthoMTA, Zirconium (Zr) in RetroMTA, Barium (Ba) and Zr in BioDentine, and Ba in ProCal.
• Radiopacity values significantly differed among materials (p < .05).
• The radiopacity ranking was: RetroMTA (3.36 ± 0.29 mm Al) > OrthoMTA (2.56 ± 0.19 mm Al) > BioDentine (2.02 ± 0.12 mm Al) > ProCal (1.46 ± 0.60 mm Al).

Conclusions:

• RetroMTA and OrthoMTA exhibit distinct radiopacity values and spectral characteristics.
• The pixel-based quantification method is reproducible and applicable for assessing radiodensity in digital radiography.
• This study provides crucial data on the radiopacity of commonly used dental materials.