Vibration analysis of maxillary removable partial denture frameworks.

The purpose of this study was to investigate the vibratory characteristics of three designs of the Class I Kennedy maxillary removable partial denture frameworks as the basic study. Their major connectors comprised a U-shaped palatal connector (UPC), single palatal bar (SPB), and anterior-posterior palatal bars (APB). Frequency response functions were measured when the framework was impacted. The modal shape was observed and the decay rate was calculated using modal analysis software. The results showed that the vibratory properties of each framework differed from each other. Within the range of frequencies from 10 to 2000 Hz, the UPC type had seven natural frequencies, while the SPB and the APB types had six. The UPC type had a greater number of natural modes accompanied by elastic deformation, including fluttering and twisting, than the other type, and the UPC type was considered to be unfavourable. The decay rate of the APB type was significantly higher than those of the UPC and the SPB types (P < 0.01).