Future Dental Journal of Egypt


The choice of material and sequence of finishing & polishing of pressed ceramics which are broadly used for indirect restorations applying different polishing methods on the glazed ceramic surfaces has not been agreed on yet so a comparison of different finishing protocols on the mechanical strength of pressed ceramics in a clinical simulating trial is of a paramount significance, in this study The effect of different grinding & finishing procedures on the biaxial flexural strength of pressed ceramics was evaluated. Material and methods: all ceramic Ips emax press discs were fabricated with a circular projection in the middle to simulate a high spot in the finished restoration. The discs were divided randomly according to grinding Speed into2 groups (n ¼ 30) high speed grinding & low speed grinding then were distributed into 3 sub groups (n ¼ 10) according to finishing procedures. Determination of biaxial flexural strengths of the disks was done using The universal testing machine then 2 way ANOVA test and Pearson correlation analysis were done. Results: Finishing procedure with High speed grinding showed lower flexural strength compared to low speed grinding with different groups. (Grinding with no finishing) group showed lowest value followed by (Grinding and finishing with rubber tips) group followed by (Grinding and finishing with rubber tips & diamond paste) group with high speed and low speed. Conclusions& significance: Grinding & finishing procedures of pressed ceramics showed significant effect Of drill speed and polishing technique over flexural strength, As Grinding with no finishing and polishing procedure showed lowest flexural Strength values followed by finishing and polishing procedure followed by finishing and polishing with polishing paste procedure