Vitro Experimental Study On The Fit Of Finesse All Ceramic Crown

Objective: This study was to measure marginal opening and cement thickness of Finesses all ceramic crown and provide theoretic foundation for clinical application of Finesse all ceramic crown. Material and metbods:30 working glass dies simulating prepared the maxillary central incisor for all ceramic crown were fabricated .The margins for the dies were a 90-degree shoulder with round axio-gingival-line angle, 1.0mm in width .The dies had an axial taper 5 degrees and were 8mm hight.30 dies were randomly divided into 3 groups(ABC),each group had 10 dies. A group for metal crown, B group for porcelain fused to metal crown and C group for Finesses all ceramic crown. All crowns were made in accordance with their manufacture抯 recommendations, then were. seated on their respective glass die with finger pressure for 10 minutes .The marginal openings before cementation were measured by using a video-enhanced measuring microscope with digital micrometer. All crowns were cemented with poly-carboxylic acid zinc cement and seated on their respective glass die by finger pressure and sustain for 10 minutes. The cemented crowns were embedded individually with epoxy resin and section buccolingually into two slices. The margin opening and cement film thickness were measured by using the same video-enhanced measuring microscope with digital micrometer The data were statistically analyzed with a one-way analysis of variance and T-test. Results: Before cementation the marginal opening of the metal crown was 27.32 ?.8 1 it m, the porcelain fused to metal crown was 29.99?13.57 1? m, Finesse all ceramic crown was 37.61 ?9.13 it m. The Statistical analysis indicated that there was no significant difference among the three group crowns. After cementation the marginal opening of the metal crown was 57.11 ?18.93 it m, the porcelain fused to metal crown was 61.49?17.95 1-i m, Finesse all ceramic crown was 65.85 ?15.11 i~ m, the cement thickness of the metal crown was 40.63 ?.01 i.~ m, the porcelain fused to metal crown was 4 1.64?17.21 1.t m, Finesse all ceramic crown was 40,84 ?9.73 14 m, there also were no significant difference among three groups crowns However, the marginal opening of each group crowns had statistically significant difference between before cementation and after cementation. Conclusion: (1) Our studies showed that Finesse all ceramic crown yield acceptable marginal fit and could satisfy the clinical demand;(2) The results indicated that cementation of crown had great effect on the marginal fit;(3) The thickness of die space had some effect on Cement抯 thickness and equitability;(4) Sand-blast had more effect on the finesse all ceramic crown than the mental crown and procelin-fused mental crown.