Compressive strength of premolars restored with ceramic crowns and supported with a glass fiber post using different luting agents.

Objective: The retention of glass fiber post (GFP) is considered a key factor for the long-term success of restorations of endodontically treated teeth. This study aimed to compare the compressive strength of a ceramic crown supported by a GFP using different luting agents.

Methods: Forty single-rooted premolars were randomly divided into four groups (n = 10 each): control group (teeth without a GFP), Ketac Cem group (glass ionomer), RelyX ARC group (conventional dual-curing resin), and RelyX U200 group (self-adhesive dual-curing resin).

Effects of oxygen in lungs of rats.

Purpose: To analyze microscopically the effects of different concentrations of oxygen in the lungs of rats.

Methods: There were 20 rats distributed in three experimental groups (concentration of oxygen to 40%, 70% and 100%) and a control group. The animals were exposed to the oxygen in a chamber of acrylic during three days and after exposition, the animals were submitted to median thoracotomia to remove the lungs.