The Impact of Different Application Techniques on Fiberglass Casts: A Mechanical Experimental Study

Cast immobilization is a part of treatment in most of the orthopaedic injuries. The fiberglass material has several advantages over plaster of Paris which makes it more preferable. Some techniques are frequently used in daily fiberglass cast application to ease molding, shorten curing time and increase stiffness. The aim of this study is to assess the effects of two techniques on fiberglass cast strength and curing time.

A cruris model was prepared to mimic a patella tendon bearing (PTB) cast. Three groups were created for the study (n = 30 each). The casts in the first group were treated with foam soap during molding. The casts in the second group were wrapped with a wet bandage after application. The third group was the control group. The samples were mechanically tested in the 5th, 15th and 30th min. Maximum load, elastic strength, and Young's modulus were assessed via 3-point bending. All data were compared using linear regression analysis and p < 0.05 was determined as statistical significance.

The results showed statistically significant improvement in cast mechanics in the wet bandage group at full curing time by means of maximum load, elastic strength and Young's modulus (p < 0.0001). Although the foam soap group had higher values in the 5th and 15th min, there was no statistically significant difference from the control group at full curing time (p > 0.05).

This study revealed that wet bandage wrapping over circular fiberglass casts improved the cast strength. The use of foam soap during fiberglass cast molding did not alter cast mechanics at full curing time.