Effects of Disinfection Methods on Cytotoxicity in Dentin Barrier Testing

Objectives: To investigate the effects of two disinfection methods for dentin disks on cytotoxicity of dentin contacting materials in a dentin barrier test.
Methods: Forty intact human third molars were freshly extracted and cut, close to the pulp chamber, into dentin disks with a 300-µm thickness. The disks were randomized (n = 20 each) into a 70% ethanol group (acid-etched dentin disks soaked in 70% ethanol for 15 min) and a steam autoclaving group (acid-etched dentin disks autoclaved for 25 min). After disinfection, each group disks were used to evaluate the cytotoxicity of both total-etching adhesive (GLUMA Bond5) and self-etching adhesives (Single Bond Universal) in the dentin barrier test. Test materials and controls were applied to the occlusal side of human dentin disks. The 3D-cell scaffolds were placed beneath the dentin disks. After a 24-h contact with the dentin barrier test device, cell viabilities were measured by performing MTT assays. Statistical analysis was performed using the Mann–Whitney U test.
Results: GLUMA Bond5 reduced the cell viability to 40% (the 70% ethanol group) and 67% (the steam autoclaving group). Single Bond Universal reduced the cell viability to 84% (the 70% ethanol group) and 87% (the steam autoclaving group).
Conclusions: The cytotoxicity of test materials decreased when using the dentin disks disinfected by steam autoclaving, indicating the steam autoclaving may affect the permeability of dentin disks, thereby affecting the cytotoxicity results.