IADR Abstract Archives
Curing Conditions Affect Flexural Strength of FRC Post
Objectives: Root canal anchoring can be made with prefabricated fiber-reinforced composite (FRC) posts or individually formed fiber post (IFP) concept. The prefabricated FRC post is polymerized industrially to a high degree of cure, whereas in the IFP concept post is cured in situ in the root canal. This study compared bending strength of industrially polymerized FRC posts with FRC materials polymerized in conditions simulating in situ curing concept. Radiopacity of the materials was also measured.
Methods: Three different FRC materials were tested. Group 1: prefabricated FRC posts, GC Fiber Post (GC, Japan) with high degree of cure (cured by manufacturer). Group 2: Individually formed FRC posts, everstick POST (GC, Japan), rolled into the form of posts between Mylar film and light-polymerized 3 x 40 s with dental light-curing device. Group 3: Individually formed FRC posts of ECR-glass fibers impregnated in a mixture of UDMA(95%) and PMMA (5%) and light-polymerized 2 x 20 s. Flexural strength of the posts (n= 6 per group) was measured with three-point bending test (span length= 10mm). Radiopacity of the posts was asessed and compared to aluminum standard.
Results: Flexural strength was significantly higher for FRC posts (1041 MPa) in Group 1 compared to posts in Groups 2 (675 MPa) and 3 (662 MPa) (p<0.05; ANOVA). No significant difference was found between the posts in Group 2 and 3. The FRC posts in Group 1 showed significantly higher radiopacity compared to the other groups. The FRC posts in Group 3 had slightly higher radiopacity compared to the posts in Group 2.
Conclusions: Individually formed and cured FRC posts have lower bending strength compared to industrially polymerized FRC post material. This highlights the importance to use in situ curable FRC with the concept of "individually formed FRC post system" which compensates the lower bending strength by allowing higher fiber volume and direct adaptation of the FRC in the root canal.
Methods: Three different FRC materials were tested. Group 1: prefabricated FRC posts, GC Fiber Post (GC, Japan) with high degree of cure (cured by manufacturer). Group 2: Individually formed FRC posts, everstick POST (GC, Japan), rolled into the form of posts between Mylar film and light-polymerized 3 x 40 s with dental light-curing device. Group 3: Individually formed FRC posts of ECR-glass fibers impregnated in a mixture of UDMA(95%) and PMMA (5%) and light-polymerized 2 x 20 s. Flexural strength of the posts (n= 6 per group) was measured with three-point bending test (span length= 10mm). Radiopacity of the posts was asessed and compared to aluminum standard.
Results: Flexural strength was significantly higher for FRC posts (1041 MPa) in Group 1 compared to posts in Groups 2 (675 MPa) and 3 (662 MPa) (p<0.05; ANOVA). No significant difference was found between the posts in Group 2 and 3. The FRC posts in Group 1 showed significantly higher radiopacity compared to the other groups. The FRC posts in Group 3 had slightly higher radiopacity compared to the posts in Group 2.
Conclusions: Individually formed and cured FRC posts have lower bending strength compared to industrially polymerized FRC post material. This highlights the importance to use in situ curable FRC with the concept of "individually formed FRC post system" which compensates the lower bending strength by allowing higher fiber volume and direct adaptation of the FRC in the root canal.