Analysis of enamel structure and mineral density after different bleaching protocols using micro-computed tomography

Area of Science:

• Dental materials science
• Biomaterials engineering
• Laser dentistry

Background:

• Dental bleaching is a common cosmetic procedure.
• Concerns exist regarding the potential structural damage to enamel from various bleaching agents and activation methods.
• Micro-computed tomography (Micro-CT) offers high-resolution analysis of dental hard tissue changes.

Purpose of the Study:

• To evaluate the impact of three different bleaching applications on enamel's structural integrity, mineral volume, and density.
• To assess the color-changing effectiveness of these bleaching methods using CIEDE2000.

Main Methods:

• Twenty-four premolar teeth were divided into three groups: 40% hydrogen peroxide (HP) with Er,Cr:YSGG laser, 40% HP with diode laser, and 16% carbamide peroxide (CP).
• Color alteration was measured using CIEDE2000 before and after bleaching.
• Micro-CT scans were performed pre- and post-bleaching to analyze enamel structure.

Main Results:

• No significant differences in color change were observed among the three bleaching groups.
• Micro-CT analysis revealed significant alterations in enamel's structural thickness, separation, mineral density, and mineral volume across all groups post-bleaching.
• The Er,Cr:YSGG laser group showed less structural harm compared to diode laser and CP groups.

Conclusions:

• All tested bleaching methods demonstrated comparable color-altering efficiency.
• Bleaching with Er,Cr:YSGG laser appears to be less detrimental to enamel's structural integrity than diode laser activation or CP bleaching.
• Findings may aid in developing standards for laser-assisted dental bleaching.