Push-Out-Bond-Strength Of Fiber Posts And Additional Fillers In Root Canals

Objectives: To investigate the push-out-bond strength of fiber posts cemented in root canals in conjunction with either dental cement or dental cement and fiber cones or dental cement and unidirectional fibers. The goal was to find out if additional material in the root canal replacing the cement has an effect on the push out bond strength.
Methods: 18 extracted human central incisors were used by cutting off crowns. Root canals have been performed using rotary instruments(WaveOneGold,Dentsply) up to size Large(040.08and25mm). The canals have been filled with guttapercha points and sealed(Ribbon,ThermaSealPlus,Dentsply). Unicore post drills(size-yellow) were used for 12mm into the canal. The canal was flared out from a bottom diameter of 1.15mm to a top diameter of 3.2mm using a prefabricated master pattern. The 18 roots were divided into 3 groups:1.BASELINE one fiber post cemented(Unicore,Ultradent,size-yellow) with the Prelude adhesive system(Danville) using Rockcore cement A2 in the autocure mode. 2.CONES same size fiber post in the center and 4 additional fiber cones inserted around. 3.FIBERS same post size and in additional unidirectional fibers(QuartzSplintUD,RTD,France) for 5mm into the canal. The roots have been stored for 24h at 100% humidity and 37°C before sectioning into 1 mm slices to obtain a coronal, middle and apical slice. All slices have been subjected to a push-out-bond-strength-test at a universal-testing-machine INSTRON-1011 at a crosshead speed of 1mm/min. Regression analysis using R-Software was used at a 95% confidence interval.
Results: A statistical significant difference was found among the groups(p=0.0173) and among the position(p=0.0024)
Conclusions: The FIBERS displaced most the resin and had highest average bond strength followed by the CONES and BASELINE group. In all groups the APICAL samples showed the highest strength.