The aim of our study was to compare the fracture resistance of teeth presenting non-carious cervical lesions restored with different types of esthetic composite materials. 20 extracted unspoiled maxillary first molars were mechanically cleaned and immersed in saline solution containing 0.1% thymol at 4�C for a period of 48 hours. Cervical cavities with a cervical-occlusal diameter of 2 mm and a mesial-distal diameter of 3mm were filled with ormocer, flow nano-composite, nano-composite and compomer. Fracture resistance was tested with a universal loading machine (Lloyd Instruments), with a maximum force of 5 kN and a crosshead speed of 1.0 mm/min; the authors used NEXYGEN Data Analysis Software and ANOVA method. For the group A (commercial grade ormocer), the smallest load that determined the sample failure was 650 N and the highest load was 1050 N, the mean value being 858 N � 150.89 N. For the group B (commercial grade flow nano-composite), the smallest load is 530 N, the highest load is 800 N, mean value being 654 N � 112.6 N. For the group C (commercial grade nano-composite), the smallest load is 680 N, the highest load is 1200 N, mean value being 926 N � 209.35 N. For the group D (commercial grade compomer), the smallest load is 1100 N, highest load is 1250N, mean value being 1180 N � 62.04 N. A p value of 0.000311 (p[0.05) shows that there are significant differences between the four groups. Conclusions. The best fracture resistance of teeth presenting non-carious cervical lesions, restored with different types of esthetic composite materials is assured by the compomer, followed by the nano-composite, which proved to be superior to ormocer. The flow nano-composite gives the lowest fracture resistance.
Application and safety assessment for nano-composite materials in food packaging