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Investigation of Dynamic Loading Fatigue of PMMA Resin Provisional Crowns

A temporary crown or bridge is the best protection of a prepared tooth from pain, saliva contamination and caries propagation. It must have all the properties and qualities of a permanent restoration in order to properly function in the oral cavity. The aim of the investigation was to determine the influence of two types of cervical preparation of the abutment, as well as the influence of cyclic thermal changes (5°C-55°C), on the dynamic strength of temporary crowns made of poly(methilmethacrylate) resin. The fatigue tests were performed in an Amsler's high frequency pulzator under cyclic dynamic loading in the range from 400N to 1000N. The results of the investigation showed negative reciprocal relationship between the values of the dynamic load and the number of cycles endured without the fracture of the sample (r=-0.98). The thermocycled samples demonstrated significantly lower fracture resistance than the nonthermocycled samples (p>0.05).