Abstract
Objectives. The aim of this study was to investigate the influence of clinical handling on the flexural and compressive strengths of two commerically available posterior composites. Methods. Since the manufacturing of test specimens in a truly clinical situation presents many problems, an in vitro model was developed, consisting of a phantom-head set-up in a clinical operatory. Two composite materials, recommended for use in posterior teeth, were used: P50 APC (3M Dental Products) and Herculite XRV (Kerr, Dental Manufacturing). Beam specimens for 3-point bending tests of both materials and cylindrical specimens for compression tests of P50 were made both under ideal laboratory circumstances and under simulated clinical circumstances. Results. The difference in mean flexural strength between laboratory prepared and the quasi-clinically prepared specimens was highly significant for both composites (p<0.002). The reduction in mean flexural strength for the specimens handled in a clinical manner was 15% of the flexural strength of the P50 specimens made under laboratory conditions, and the difference for Herculite XRV was 29%. No difference in compressive strength could be shown between the laboratory-fabricated and the quasi-clinically made specimens of P50. Significance. The relative flexural strength of composite materials in a clinical situation may differ significantly from that predicted from mechanical properties measured in vitro.
Submitted Version (
Free)
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call