Evaluation of the marginal fit of a zirconia ceramic computer-aided machined (CAM) crown system

Multifactorial analysis of the impact of different manufacturing processes on the marginal fit of zirconia copings

“…For the manual adapted copings, the mean marginal gaps varied from 54 to 59.9 μm. This is in accordance with marginal gaps reported for CAD/ CAM-generated zirconia copings in other studies, in which marginal gaps ranged from 24 to 110 μm 6,11,14,15,31) . The large variation in the reported mean values can be explained by a number of infl uencing factors, including CAD/CAM components and differences between presintered and post-sintered milling of the zirconia blank.…”

“…The large variation in the reported mean values can be explained by a number of infl uencing factors, including CAD/CAM components and differences between presintered and post-sintered milling of the zirconia blank. In in vitro studies using the same CAD/CAM system (Cercon) such as the present study, mean values for marginal openings were reported to range from 38 to 66 μm 11,27,31) . The variation in reported mean values of samples derived from the same CAD/CAM system can be explained by differences in study designs and measurement techniques, including evaluations of cemented or non-cemented crowns; various preparation designs of abutments; different types of microscope/ magnifi cations used for the measurements; and the location and quantity of single measurements 6) .…”

“…Evaluation of the mean marginal gaps (calculated by 20 copings per sample series ×24 measurement points per coping) was performed according to the literature 11,18,26,30) as well as by considering the averaged maximum marginal gap within one system or parameter (calculated only by the maximum values of each coping within one sample series). Data are expressed as means with standard deviations and 95% confi dence intervals.…”

“…It has been reported that allceramic crowns show a mean marginal discrepancy that ranges from 19-160 μm [7][8][9][10] . The mean marginal gap for CAD/CAM-generated crowns is reported to be 23-110 μm 6,[11][12][13][14][15] . Many authors accept the criterion established by McLean and von Fraunhofer (1971) who proposed after a 5-year examination of 1,000 restorations that 120 μm should be considered the maximum marginal gap 6,[15][16][17] .…”

The marginal fit of E.max Press and E.max CAD lithium disilicate restorations: A critical review

“…This technique reduces processing errors that may be associated with conventional sintering and has been shown to improve mechanical stability 21,22) . Marginal fit is an important factor in the success of restorations 23,24) . Marginal fit is related to both vertical and horizontal discrepancies.…”