COMPARISON OF FRACTURE RESISTANCE IN 1.3 MOUNT-HUME LESIONS RESTORED WITH COMPOSITE RESINS WITH AND WITHOUT POLYETHYLENE FIBER REINFORCEMENT.

Abstract: OBJECTIVES: To evaluate and compare the fracture resistance of natural teeth restored with different types of fillings in Mount-Hume class 1.3 preparations.METHODS: 15 healthy human premolars were selected. Occlusal preparations, 3 mm deep by 3 mm wide, were prepared with a medium and fine grain stone 845kr iso 025 undergroup), without preparation; Group 2: A nanoparticulate composite resin Z350 Filtek 3M ESPE was used as a filling, restoration continued using an incremental technique in layers cured for 30 seconds with the VALO™ Grand lamp in its standard function. Group 3: A high-load composite Flow liner, 3M™ Filtek™ Supreme Flowable, was applied. Ribbond fibers were positioned and light-polymerized with the VALO™ Grand lamp in its standard function for 30 seconds. Incremental technique was continued using nanoparticulate composite resin Z350 Filtek 3M ESPE. The samples were analyzed using an Instron 1011 TENSILE TESTER. Continuous compression force was applied until the fracture limit was reached, determined in Newtons (N). Data were statistically analyzed using ANOVA followed by Student-Neuman-Keuls test. RESULTS: Fracture time: G1: 0, G2: 51.4 ± 4.36s, G3: 40.61 ± 10.4s. C vs G2 p<0.001, C vs G3 p<0.01, G2 vs G3 ns p>0.05. G3 showed the highest time record: 187.22s. Load: G1: 409.82 ± 57 N, G2: 155.28 ± 74.5 N, G3: 140.42 ± 32.6 N. C vs G2 p<0.05, C vs G3 p<0.05, G2 vs G3 ns p>0.05. The highest value was obtained for G3 with 568.8 NW. Extension: G2: 0.842 ± 0.06 mm, G3: 0.678 ± 0.17 mm. G2 vs G3 * p < 0.05. CONCLUSIONS: No statistically significant differences were observed between the groups. The control group did not show cracks before the fracture. Significant differences between the groups were observed regarding the extent of deformation caused by the instrument during loading.