Do bonding agents protect the bracket-periphery?--Evaluation by consecutive μCT scans and fluorescence measurements

Area of Science:

• Biomaterials Science
• Cariology
• Orthodontic Materials

Background:

• Enamel demineralization at the bracket periphery is a common challenge in orthodontic treatment, leading to white spot lesions (WSL).
• Fluoride-releasing orthodontic bonding agents are investigated for their potential to mitigate demineralization.
• Accurate detection methods are crucial for evaluating preventive strategies against enamel subsurface lesions.

Purpose of the Study:

• To evaluate the efficacy of three orthodontic bonding agents in preventing enamel demineralization adjacent to orthodontic brackets.
• To compare the suitability of micro-computed tomography (μCT) and quantitative light-induced fluorescence (QLF) in detecting changes within subsurface enamel lesions.
• To assess the longitudinal effects of fluoride-releasing bonding agents on WSL progression.

Main Methods:

• An in vitro study utilizing 45 teeth subjected to pH cycling for up to 28 days.
• Three bonding agents were tested: resin-modified glass ionomer cement (RMGI), compomer, and composite.
• Consecutive μCT scans and a customized QLF setup were employed to examine enamel changes.

Main Results:

• Both RMGI and compomer demonstrated a decrease in demineralization progression compared to controls.
• QLF and μCT scans indicated a protected area adjacent to the bracket margin for RMGI and compomer.
• The formation and body of lesions were not always precisely located at the enamel next to the bracket margin.

Conclusions:

• RMGI and compomer comparably reduced WSL progression, with RMGI offering marginally superior protection.
• Both μCT and QLF are suitable methods for longitudinal investigation of fluoride effects on WSL.
• Mineral loss or volume changes provided more accurate descriptions of lesion progression than lesion depth.