Friction And Wear Behavior Of Natural Tooth And Dental All-ceramic Veneering Porcelain

Objective: The aim was to study and explore the friction and wear behavior between the enamel/dentine, three types of dental decoration porcelains for all-ceramic restorations against the same counter sample. Materials & Methods: The study of friction and wear behavior of enamel and dentine was done under dry/artificial saliva lubrication. And the aging change of natural tooth was also investigated, as well as load/frequency and manufacture factors. A variety of factors including Vickers hardness, fracture toughness, flexural strength, friction coefficients, wear scar width, element concentrations and wear surface evolution were considered relative to the tribology of that in vivo situation. The wear scars of the samples were characterized by means of scanning electron microscopy (SEM) and atomic force microscopy (AFM). The different element concentrations of the surface before/after the wear test were determined with energy dispersion spectrometry (EDS).Results:1. Results showed that there existed statistical significance in enamel and dentine. The statistical differences were observed both in wear width and hardness of materials in different groups (p＜0.05). Enamel and dentine displayed good wear resistances. The wear ability of enamel is better than that of dentine, both two materials displayed better resistance with artificial lubrication instead of dry friction. SEM/AFM results showed wear surface natural tooth full of abrasive particles and denaturation of dental texture. The wear resistance ability ranked from high to low as follows: adult group, young group, old group.2. Enamel, Vita-alpha, Cercon and Vintage-al displayed good wear resistances. The statistical differences between materials were observed in wear width and properties of materials (p＜0.05). The wear ability among four materials ranked from highest to lowest as follows: Vintage-al, Cercon, Vita-alpha, enamel. SEM/AFM results demonstrated the wear patterns of tested veneering ceramics consisted mainly of abrasive wear, adhesion and fatigue wear. The EDS results showed that antagonist substance had been transferred to the porcelain surface, the element concentration of Fe was obviously found on the samples.3. With the load/frequency increasing, the friction and wear behavior of natural tooth and veneering were worse than lower level.4. The wear behavior of veneering samples with glazing or polishing was different at first stage, but difference didn't exist after the whole experiment. There was no difference among veneering with different sintering temperature. The wear behavior of veneering with different vacuum was different. The wear scar width widened, while the vacuum pressure decreasing. There existed a negative correlation between the vacuum pressure and wear behavior. Firing times could weaken the wear ability of veneering with the wear scar width increasing. There existed positive correlation between them.Conclusion:The wear resistances of enamel and dentine are good and stable. The artificial saliva plays an important role in the wear behavior of enamel and dentine. The main underlying mechanisms of natural teeth wear are abrasive, and denaturation of dental texture. The wear resistance ability of enamel against wear is better than that of dentine. The wear resistance ability ranked from high to low as follows: adult group, young group, old group.Veneering ceramics wear ability is better than natural human teeth. The resistance ability of veneering ceramics against wear may have some correlation with the ceramics mechanical properties such as hardness, fracture toughness and flexural strength. The wear patterns of veneering ceramics can be described as mild wear. Abrasive wear, adhesion and fatigue of veneering ceramics characterize the wear patterns.Load and frequency can influence the wear behavior of all-ceramic veneering porcelains.Glazing can influence the wear ability against wear at first stage. There isn't a statistical difference among veneering porcelains wear resistance during the temperature range. Sintering vacuum can significantly influence the ability. Firing times can change the behavior.