Retention of two types of machine milled Non metallic crowns luted with two adhesive resin techniques / Mona Edris Abdelhamid ; Supervised Mohammed Labib Zamzam , Rasha Nabil Mohammed Sami

Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Prosthodontics

This study was designed to evaluate the retention of two different crown materials using two different luting cements. Twenty intact human molars were used; teeth were divided into two main groups according to the crown material used, each group has (10) samples. Each group was further subdivided into two subgroups according to the type of resin cement, each of (5) samples. Standardized tooth preparation was carried out by milling machine to have: convergence angle of 10 degree, flat occlusal reduction and 1mm deep chamfer finish line. Occluso-gingival height was 4mm. Copings were fabricated according to manufacturer {u031B}s instructions using two types of crown materials: lava ultimate CAD CAM blocks and IPS e.max CAD blocks. Milling was carried out using Cerec Inlab machine. Milled copings were cemented to the prepared teeth using rely X U200 self adhesive resin cement and Rely X ultimate total etch resin cement. All samples were then tested for tensile bond strength. Regarding the effect of the type of the crown material: it was found that Lava group recorded statistically non-significant (P>0.05) higher retention mean value than e.max group. Regarding the effect of cement type on the tensile bond strength of tested crowns, results revealed that rely X U200 self adhesive resin cement showed statistically non significantly higher mean tensile bond strength than that recorded for rely X Ultimate total etch resin cement. Results of the effect of the variables combination (type of crown material and cement type) on the tensile bond strength revealed that. Lava Ultimate with Rely X U200 self-adhesive resin cement) group produced the highest tensile bond strength compared with combination groups

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