OBJECTIVES. Monolithic all-ceramic fixed partial dentures are reported to be cost-effective and more resistant than layered counterparts. Monolithic crowns are more resistant to a type of failure called chipping and also aesthetically acceptable.Lithium disilicate blocks can be milled to obtain aesthetic, stronger and cheaper prosthetic manufacturing: without layering, lead times and costs are highly reduced.Although monolithic crowns seem to be more advantageous, during the layering process, crowns are submitted to the same thermic cycle as the monolithic, but this may yield different results as to marginal gaps. The aim of this study is to compare the fitting of monolithic and layered lithium disilicate all-ceramic crowns using the replica technique.MATERIALS AND METHODS. An upper incisor and a canine were prepared to receive ceramic restoration. For each tooth, 6 monolithic and 6 layered crowns were replicated using CAD/CAM technology and IPS e. max (R) CAD lithium disilicate blocks (Ivoclar-Vivadent, Shaan, Liechtenstein), thus obtaining 24 crowns divided into 4 groups: Group A, layered incisors; Group B, layered canines; Group C, monolithic incisors; Group D, monolithic canines. In order to determine the marginal gap, materials of two different colours were used for the replica technique. When the replica was obtained, it was cut into four pieces and observed through the microscope and the four marginal points could be measured thanks to the two different material colours.RESULTS. All crowns showed a marginal gap of over 100 mu m with different valuves in each group; such differences, however, are not statistically significant and are neither correlated with the fabrication technique, nor with the type of tooth.CONCLUSIONS. There is no statistical significance in the difference between monolithic and layered crowns marginal gaps. Although both types of crowns were obtained with the same CAD/CAM technology, the layering process is not involved in the precision level of marginal gaps.
Gobbetti, E., Baldissara, P. (2016). Fitting of monolithic (full-contour) versus layered lithium disilicate all-ceramic crowns. DENTAL CADMOS, 84(4), 242-247 [10.1016/S0011-8524(16)30050-2].
Fitting of monolithic (full-contour) versus layered lithium disilicate all-ceramic crowns
Baldissara, P
2016
Abstract
OBJECTIVES. Monolithic all-ceramic fixed partial dentures are reported to be cost-effective and more resistant than layered counterparts. Monolithic crowns are more resistant to a type of failure called chipping and also aesthetically acceptable.Lithium disilicate blocks can be milled to obtain aesthetic, stronger and cheaper prosthetic manufacturing: without layering, lead times and costs are highly reduced.Although monolithic crowns seem to be more advantageous, during the layering process, crowns are submitted to the same thermic cycle as the monolithic, but this may yield different results as to marginal gaps. The aim of this study is to compare the fitting of monolithic and layered lithium disilicate all-ceramic crowns using the replica technique.MATERIALS AND METHODS. An upper incisor and a canine were prepared to receive ceramic restoration. For each tooth, 6 monolithic and 6 layered crowns were replicated using CAD/CAM technology and IPS e. max (R) CAD lithium disilicate blocks (Ivoclar-Vivadent, Shaan, Liechtenstein), thus obtaining 24 crowns divided into 4 groups: Group A, layered incisors; Group B, layered canines; Group C, monolithic incisors; Group D, monolithic canines. In order to determine the marginal gap, materials of two different colours were used for the replica technique. When the replica was obtained, it was cut into four pieces and observed through the microscope and the four marginal points could be measured thanks to the two different material colours.RESULTS. All crowns showed a marginal gap of over 100 mu m with different valuves in each group; such differences, however, are not statistically significant and are neither correlated with the fabrication technique, nor with the type of tooth.CONCLUSIONS. There is no statistical significance in the difference between monolithic and layered crowns marginal gaps. Although both types of crowns were obtained with the same CAD/CAM technology, the layering process is not involved in the precision level of marginal gaps.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
