Fracture resistance of CAD/CAM ceramic overlays with different reinforcing and biomimetic composite resin base

Background Teeth lose strength after preparation specially with mesio-occluso-distal cavities. Using different materials with physical properties near to natural teeth structure to regain teeth strength. This in-vitro study was performed to evaluate fracture resistance of CAD/CAM ceramic overlays with different reinforcing and biomimetic composite resin base. Materials and Methods Thirty-six extracted sound maxillary premolars were used in this study. Teeth were divided into three main groups ( n = 12), group 1 (G1): intact teeth (control group), and the other two groups divided according to method of reinforcement as group 2 (G2): smart dentin replacement bulk fill resin base, and group 3 (G3): polyethylene (Ribbond) fibers with short-fiber reinforced (SFC) composite resin base. Nacera hybrid ceramic overlays were fabricated and adhesively cemented. Specimens underwent thermocycling and cyclic loading for aging. Specimens underwent a compressive load till fracture (fracture resistance test). Broken specimens have been analyzed to ascertain the fracture pattern by a digital microscope. Results Highest fracture resistance was seen for G3: 1171.75 ± 257.99, and the lowest value was for G1: 876.09 ± 184.79 with significance ( P > 0.05). Highest significant repairable fracture patterns were in G3 (75%) then G2 (66.67%) and G1 (58.34%). Conclusion Within the limitation of this study, restoring badly decayed premolars with materials resemble nature (EverX posterior and Ribbond fiber reinforced composite with Nacera hybrid ceramic) has better fracture resistance and repairable fracture modes.