Toothbrushing abrasion of polyacid-modified composites in neutral and acidic buffer solutions

Statement of problem. Polyacid-modified composites are recommended for use in lesions that are subjected to toothbrushing abrasion and acidic challenges, such as cervical lesions. There is little information whether these materials are able to withstand degradation due to erosive attacks and toothbrushing abrasion. Purpose. This study evaluated the resistance of polyacid-modified composites against toothbrushing abrasion under acidic and neutral conditions. Methods. Forty specimens fabricated of each of two polyacid-modified composites (Dyract, Compoglass) were investigated. For each composite group, 20 specimens were placed in a neutral solution (pH: 6.5) and 20 specimens were placed in an acidic solution (pH: 3.0) for 24 hours. All specimens were brushed in an automatic toothbrushing machine, then subjected to storage in the respective buffer solution (8 hours), followed by brushing three times. Abrasion was determined profilometrically. Results. For both materials, abrasion in the acidic environment was significantly higher compared with neutral conditions. Thus, Compoglass composite demonstrated a lower abrasion resistance than Dyract composite. Conclusion. The abrasion resistance of the investigated materials was reduced under acidic conditions.