Confocal laser scanning microscopic observations of secondary caries inhibition around different types of luting...

To analyze in vitro artificial secondary caries inhibition around conventional luting cements and resin cements using a confocal laser-scanning microscope (CLSM).

Box shape cavities (approximately 3 mm long, 4 mm wide, and 1.5 mm deep) were prepared in bovine root dentin. One of five cements: Elite Cement 100 (EL) zinc phosphate cement, HY-Bond Carbo Cement (CA) polycarboxylate cement, Fuji I (FI) glass-ionomer cement, Fuji Luting (FL) GIC-based resin cement and Panavia F (PA) fluoride-releasing resin cement, was placed in the cavity. After polishing, the center of the cement surface was covered with an adhesive to preserve the original cement solubility. The specimens were stored in distilled water at 37 degrees C for 1 week, and stored in an artificial demineralizing solution for 3.5 days. Following this, each specimen was sectioned into two halves, trimmed, and polished. Thickness of inhibition zone, depth of outer lesion and cement solubility around each cement were determined by a CLSM.

Inhibition zones were not seen in EL and CA, while they were found in FI, FL and PA. The depths of the outer lesions of CA and FI were significantly lower than those of EL, FL and PA (P< 0.05). The highest and the second-highest cement solubility were obtained in EL and CA, respectively. FI and FL indicated significantly lower cement solubility than EL and CA. PA tended to show the lowest cement solubility.