Accuracy of fit of ceramic-copings cemented with an experimental cement

Purpose: the aim of this study was to evaluate the marginal and internal fit of cerec3 Zirconia-based copings cemented using new experimental cement.

Materials and Methods: this investigation was made on a metal master model (36). Six conditions were established by combining three types of cements (a- experimental adhesive cement/ Voco, b- zinc phosphate/ Harvard, c- adhesive cement/ Panavia21) with two different setting of luting space (100 µm, 50 µm). A total of 30 copings specimens were milled using Vita In-Ceram YZ blanks, 5 pieces for each condition. The cemented copings were embedded in acrylic resin then sectioned longitudinally bucco-lingually and mesiodistally. Widths of the marginal gap (MG) and internal gap (IG) were measured using a light microscope 82 measurements were made for each sample.

Results: The mean values and SD are summarized in the table.1. One way ANOVA test showed significant differences between the results of copings produced with cement spacer of 100 µm and those of 50 µm spacer, also between zinc phosphate cement and the other two adhesive cements.

Table. 1

cement	Spacer 100µm		Spacer 50µm
	MG	IG	MG	IG
Zinc phosphate	45,59 ± 6,82	113,35 ± 2,48	71,26 ± 3,34	87,67 ± 10,20
Panavia21	31,57 ± 9,16	102,87 ± 1,96	61,54 ± 5,97	71,42 ± 4,29
Experimental	44,01 ± 10,52	117,22 ± 7,98	68,64  ± 15,14	104,84 ± 11,02

Conclusion: accuracy of fit of copings cemented with the experimental cement is comparable with Panavia21 and zinc phosphate cement. Results of copings with 100 µm spacer were better than those of copings produced with 50 µm. For the new cement is recommended a spacer of 100 µm because the high variation in case of using spacer of 50 µm.