Noninvasive diagnostic method using optical coherence tomography detected a vulnerable dentin enamel junction created...

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Diagnostic Imaging

Background:

• The dentin enamel junction (DEJ) is crucial for dental integrity.
• Understanding the effects of etching agents on the DEJ is vital for restorative dentistry.
• Non-invasive imaging techniques can aid in assessing DEJ alterations.

Purpose of the Study:

• To evaluate the impact of phosphoric acid etching on the DEJ.
• To compare the effectiveness of optical coherence tomography (OCT) with other microscopy techniques in visualizing DEJ changes.
• To assess the influence of etching on the ultimate tensile strength (UTS) of the DEJ.

Main Methods:

• Human teeth were treated with different etching agents (SE Bond2 primer, Enamel Conditioner, K-etchant syringe) or no treatment (control).
• The DEJ was analyzed using confocal laser scanning microscopy (CLSM), OCT, and scanning electron microscopy (SEM).
• Ultimate tensile strength (UTS) tests were conducted on the treated DEJ specimens.

Main Results:

• SEM revealed cracks in all etched samples, while CLSM did not show cracks.
• OCT identified a characteristic white line at the DEJ in K-etchant and some Enamel Conditioner treated specimens.
• UTS testing indicated a significant reduction in strength for K-etchant treated samples compared to controls.

Conclusions:

• Phosphoric acid etching, particularly with K-etchant, can lead to excessive demineralization and compromise the structural integrity of the DEJ.
• OCT serves as a valuable non-invasive tool for detecting etching-induced fragility at the DEJ.
• These findings highlight potential risks associated with aggressive phosphoric acid etching protocols in dental restorations.