Microleakage Evaluation of XeraCem™ in Cemented Crowns

Long-term success after cementation of indirect restorations depends on retention as well as maintenance of the integrity of the marginal seal. A seal can be established through bonding techniques or other mechanisms. XeraCem™ has demonstrated to possess self-sealing properties through the formation of hydroxy apatite (Lööf et al. Dent Mat 2007) Objectives: To test XeraCem™ for its sealing properties. Materials and Methods: Thirty freshly extracted human molars and bicuspids were prepared free hand to full chamfer preparation using a diamond bur in a high speed hand piece under copious water cooling. The total angle of convergence measured approximately 10-12 degrees. Copings were waxed and cast in type III gold using routine laboratory techniques. 10 copings for each experimental group and 5 for the control groups were tested. Group 1. XeraCem™ after 24 hrs (n=10), Group 2. XeraCem™ with thermal cycling (TC) (n=10), Group 3. Ketac Cem after 24 hrs (n=5), Group 4 Ketac Cem with TC (n=5). The samples were coated with Block-out resin 1 mm short of the margin. They were then immersed in 0.5% methylene blue dye for 24 hrs, rinsed, imbedded in self curing resin and sectioned, thus generating a minimum of 6 samples, resulting in 12 leakage scores. Dye leakage was assessed as 0=none, 0-1mm=1, 2-3mm=2, 3-4mm=3 and >4mm=4. Results: The mean leakage for Gr. 1=0.06, Gr. 2=0.69, Gr. 3=0.58 and Gr.4=1.22 A non-parametric statistical analysis demonstrated significant differences between groups 1 and 3 and groups 2 and 4 (p<0.01) Conclusion: XeraCem™ demonstrated significantly less leakage than Ketac Cem for both the non TC and TC groups. (This study was supported in part by Doxa Dental AB)