Dentin erosion simulation by cantilever beam fatigue and pH change

Area of Science:

• Biomaterials Science
• Dental Research
• Mechanobiology

Background:

• Exposed root surfaces often show non-carious notches, indicative of material loss.
• The roles of abrasion, erosion, and abfraction are recognized, but the direct contribution of mechanical stress remains unproven.

Purpose of the Study:

• To investigate the relationship between mechanical stress and pH in dentin material loss.
• To quantify dimensional changes in dentin under cyclic fatigue in different pH environments.

Main Methods:

• Human dentin beams were subjected to cyclic fatigue under load control at pH 6 and pH 7.
• Tests were conducted with a load ratio (R) of 0.1, frequency of 2 Hz, and stresses ranging from 5.5 to 55 MPa.
• Material loss was measured in high- and low-stress areas before and after fatigue cycling.

Main Results:

• Seven out of 23 beams completed 1,000,000 cycles; others failed earlier.
• Material loss was significantly greater in high-stress areas compared to low-stress areas.
• Dentin samples exposed to pH 6 exhibited greater material loss than those at pH 7.

Conclusions:

• Mechanical stress and reduced pH act synergistically to accelerate dentin erosion.
• Findings support the hypothesis that mechanical stress contributes to the formation of non-carious cervical lesions.
• Environmental factors like pH are critical in modulating the effects of mechanical stress on dentin integrity.