[Resistance of cavity walls of composite filled teeth]

The purpose of this study was to evaluate whether etching, bonding and filling with composite a cavity increase tooth resistance to fracture, considering that in posterior teeth stressed cusps are likely to bend. MOD conservative cavities (isthmus width/intercuspal distance = 0.25) were made in 10 extracted upper premolars, filled with P30 (3M) and tested by using a MTS machine. A metal bar (5 mm in diameter and 10 mm in length) was employed to load the cusps and their fracture resistance was recorded. The control group consisted of 16 extracted upper premolars: MOD cavities were made in only 9 teeth, then filled with amalgam. As a result, MOD cavities treated with Scotchbond, filled with P30 and tested by a MTS machine don't seem to be more resistant to a static load than cavities filled with amalgam.