Laser irradiation prevents root caries: Microhardness and scanning electron microscopy analysis

Area of Science:

• Dentistry
• Biomaterials
• Laser Physics

Background:

• Dental caries, particularly root caries, poses a significant challenge in restorative dentistry.
• Laser irradiation has emerged as a promising adjunctive therapy for preventing dental caries.
• Understanding the specific effects of different laser types and their combination with fluoride is crucial for optimizing treatment strategies.

Purpose of the Study:

• To evaluate the efficacy of Erbium, Chromium-doped Yttrium Aluminum Garnet (Er:YAG), Neodymium-doped Yttrium Aluminum Garnet (Nd:YAG), and Carbon Dioxide (CO2) laser irradiation in preventing root caries.
• To investigate the potential synergistic effects of these laser treatments when combined with 2% sodium fluoride (2% NaF) application.

Main Methods:

• Human root dentin samples were divided into eight groups, receiving treatments such as 2% NaF, Er:YAG, Nd:YAG, CO2 lasers, or combinations thereof.
• Samples underwent a 2-week cariogenic challenge involving daily de-remineralization and re-mineralization cycles.
• Knoop microhardness testing was performed at various depths, and scanning electron microscopy (SEM) was used for morphological analysis.

Main Results:

• Er:YAG laser irradiation significantly increased dentin's acid resistance and surface hardness compared to all other groups.
• No synergistic effect was observed when 2% NaF was applied in conjunction with any of the tested laser types.
• SEM analysis revealed morphological changes, including carbonization and cracks, with Nd:YAG and CO2 lasers, but not with Er:YAG.

Conclusions:

• Er:YAG laser irradiation is a safe and effective method for increasing the acid resistance of root dentin.
• The combination of 2% NaF with laser irradiation did not enhance the caries preventive effects.
• Er:YAG laser treatment shows potential as a standalone or adjunctive therapy for root caries prevention.