Fixed dental prostheses with zirconia frameworks survived as long as those with metal frameworks in a randomized controlled clinical trial published in the current International Journal of Prosthodontics (November/December 2009, Vol. 22: 6, pp. 553-560.)
Researchers from the University of Berne recruited 59 patients in need of 76 fixed dental prostheses replacing one to three molars or premolars each.
They randomly assigned each case to either a zirconia or a metal framework. Then they examined prosthesis at baseline, one year, and three years.
They evaluated the technical quality of the reconstructions using the U.S. Public Health Service criteria. They evaluated the biologic outcome by measuring probing pocket depth, probing attachment level, plaque control record, bleeding on probing and tooth vitality. They also took x-rays.
After a mean follow-up time of 40.3 ( 2.8) months, four patients dropped out of the study. Among the 53 who remained, there was no statistically significant difference between the 36 zirconia frameworks and the 31 metal frameworks in biological parameters.
All of the frameworks of both types survived. Minor chipping of the veneering ceramic occurred in 25% of the zirconia-ceramic prostheses and 19.4% of the metal-ceramic ones. Extended fracturing of the veneering ceramic occurred solely in zirconia-ceramic prostheses (C: 8.6%, D: 2.8% in the USPHS criteria.)
