title: The comparative evaluation of the translucency of crowns fabricated with three different all-ceramic materials: an in vitro study.
abstract: BACKGROUND
  All-ceramic crowns with different core materials of different strength and aesthetics are available in recent years. The aesthetics of the crown depends mainly on the shade and translucency. Clinician should be aware of the quality and characteristics of these materials so that they will be able to opt for good material for successful clinical use.
  
  
  OBJECTIVE
  The aim of this study was to evaluate and compare the translucency of crowns fabricated with three different commercially available all-ceramic materials viz. Alumina - CAD-CAM Procera, Lithium disilicate - Pressable IPS e.max Press, Zirconia - CAD-CAM Lava.
  
  
  METHODS
  All-ceramic crowns (5 per each group and total of 15 samples) were made of Alumina - CAD-CAM Procera (Group I), Lithium disilicate - Pressable IPS e.max Press (Group II), Zirconia - CAD-CAM Lava (Group III) and veneered with their respective layering ceramic. Evaluation for the Translucency (CR=Yb/Yw) over the White (Yw) and Black (Yb) backgrounds at the Incisal, Middle, Cervical, Mesial and Distal thirds of each crown were done using the Spectrophotometer. The results obtained were statistically analyzed by Paired t-test (p<0.05) and Analysis of Variance (p<0.05) for the test of significance among the groups.
  
  
  RESULTS
  Significant differences in the contrast ratios were obtained among the three Groups (p<0.001). In this study, Group II Lithium disilicate-Pressable IPS e.max Press showed higher translucency (0.54). Group III Zirconia - CAD-CAM Lava showed the least translucency (0.75) and the translucency of Group I Alumina - CAD-CAM Procera (0.7) was in between both the groups.
  
  
  CONCLUSIONS
  Translucency of material gives fair idea to clinician for the choice of material in different zones during replacement and suitability for restoration in aesthetic zone. Selection of all ceramic system depends on the translucency needed for successful prosthesis of artificial tooth so that it mimics patient's natural dentition. The qualitative measurement of translucency will give the evidence for the clinicians during selection of high or low value translucent tooth for successful replacement. Lithium disilicate - Pressable IPS e.max Press is having better translucency in comparison with other two materials in our study.
authors: Senior Lecturer, Department of Prosthodontics, Lenora Institute of Dental sciences , Rajahmundry, Andhra Pradesh, India .
authors: Y
authors: Y
authors: Sravanthi
authors: Senior Lecturer, Department of Prosthodontics, Lenora Institute of Dental sciences , Rajahmundry, Andhra Pradesh, India .
authors: Y V
authors: YV
authors: Ramani
authors: Professor, Department of Prosthodontics, Padmashree Dr. D. Y. Patil Dental College and Hospital , Nerul, Navi Mumbai, Maharashtra, India .
authors: Asha M
authors: AM
authors: Rathod
authors: Professor, H.O.D, Dean, Department of Prosthodontics, M.G.M. Dental College and Hospital , Kamothe, Navi Mumbai, Maharashtra, India .
authors: Sabita M
authors: SM
authors: Ram
authors: Professor, Department of Prosthodontics, S D Dental College and Hospital , Parbhani. Maharashtra, India .
authors: Hetal
authors: H
authors: Turakhia
keywords: Aesthetics; Alumina-CAD-CAM procera; Contrast ratio; Lithium disilicate-pressable IPS e.max press; Metal free ceramics; Spectrophotometer; Transmitted light; Zirconia - CAD-CAM Lava