engleski

Assessment of cohesive fractures with or without flowable composites

Objectives: Due to their low viscosity, flowable composite resin materials can be used as shock absorbers of stress that can occur during polymerization shrinkage at the interface surface. The purpose of the study was to estimate incidence of cohesive fractures (KF) in composite fillings with and without using of flowable composite resins (FCR). Methods: 144 fillings were made, 72 with packable composite resins (PCR), of which 36 with FCR and 36 without FCR. The same procedure was repeated for hybrid composite resin (HCR). Teeth were placed in molds filled with acrylic mass. Horizontal cross-sections were made using the 1600 Leitz microtome, furnished to the shredding speed of 15 &#956; /sec. Existence and location of cohesive fractures were assessed with Olympus (Olympus Optical Co., Europa, GMBH, Hamburg, Germany) research system and OlympusDP-Soft 3.2 software for digital analysis of images. Data were processed with &#967; 2-test, Fisher test and Kruskal-Wallis test, using the SAS &copy ; System software package on Windows 95 platform (p<0.005). Results: KF occurred in 69.4% of fillings without FCR and in 48.6% of cases with FCR. In fillings with HCR, FRC does not affect statistically significant the manifestation of KF. At PCF, KF occurred in 77.8% without and at 48.6% with FCR. Conclusions: Although the frequency of appearance of KF depends on the use of current composites, analysis of dependence did not show the dependence of number of fractures to use of FCR. The appearance of KF depends on the elasticity of materials. Because of its viscosity FCR material can endure greater force before permanent deformation than two composite materials used in the study. The intensity of the formation of KF was significantly lower in PCR fillings with FCR. For HCR materials with the FCR KF will not be significantly reduced. This study was supported by MZOS project 065-0352851-0410.

cohesive fractures; flowable composites

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