en پروتزهای دندانی Prosthodontics پژوهشي Research <div style="text-align: justify;"><span style="font-size:12px;"><span style="line-height:200%"><span aptos=""><b><span new="" roman="" times="">Background:</span></b><span new="" roman="" times=""> The retention of the crown on teeth or abutment of a bridge is one of the important factors in the success of dental treatments, especially when teeth have a short crown. One factor that can affect the retention strength of crowns on such teeth is the type of cement and its relation to the core material. The aim of this study was to investigate the effect of cement type on fixed zirconia restorations.</span></span></span><br> <span style="line-height:200%"><span aptos=""><b><span new="" roman="" times="">Materials & Methods:</span></b><span new="" roman="" times=""> 60 samples were prepared in the form of a prepared tooth using a brass rod, with 11 mm length and 7 mm diameter in the margin and 6 mm in the upper part of the sample. The samples were used as an anti-rotation, and then crowns of zirconia were designed and made by CAD/CAM on the samples. Then 60 samples were randomly distributed into three equal groups (n=20) and each group was cemented with one of three luting agents: glass ionomer, zinc phosphate and panavia resin cement. The amount of force required to separate the crowns was measured by the universal testing machine. The data were analyzed by One-way ANOVA test and Tukey&#39;s post hoc test (&alpha;= 0.05).</span></span></span><br> <span style="line-height:200%"><span aptos=""><b><span new="" roman="" times="">Result:</span></b><span new="" roman="" times=""> The mean of fixed zirconia restorations in the three groups was significantly different (P <0.001). The mean of fixed zirconia restorations in the zinc phosphate cement group was significantly higher than the Panavia resin cement group (P=0.001) and in the Panavia resin cement group was significantly higher than the glass ionomer cement group (P <0.001).</span></span></span><br> <span style="line-height:200%"><span aptos=""><b><span new="" roman="" times="">Conclusion:</span></b><span new="" roman="" times=""> The use of zinc phosphate cement in comparison to Panavia and glass ionomer provides more retention for zirconia crowns.</span></span></span></span></div> 28 33 http://cofs.khuisf.ac.ir/browse.php?a_code=A-10-1-48&slc_lang=en&sid=1 Melika Saadatmand 1003194753284600830 1003194753284600830 No Faculty of Dentistry, Isf.C, Islamic Azad University, Isfahan, Iran Meysam Mahabadi 1003194753284600831 1003194753284600831 Yes Department of Prosthodontic, Faculty of Dentistry, Isf.C, Islamic Azad University, Isfahan, Iran Shadab Hashemi 1003194753284600832 1003194753284600832 No Department of Prosthodontic, Faculty of Dentistry, Isf.C, Islamic Azad University, Isfahan, Iran