Marginal and internal fit of all‐ceramic CAD/CAM crown‐copings on chamfer preparations

TLDR

The study evaluates whether CAD/CAM‑fabricated all‑ceramic molar crown‑copings achieve marginal and internal fit comparable to conventional techniques. Sixty‑two crown preparations were duplicated to produce 72 plaster dies, on which slip‑cast, heat‑pressed, and five CAD/CAM all‑ceramic crown‑copings were seated and their marginal and internal gaps measured by SEM at 120× magnification. Slip‑cast copings had the smallest marginal gaps, Empress II the largest, with Procera and Decim matching slip‑cast and smaller than Empress II and Cerec, DCS showed no significant differences, and internal mid‑orobuccal gaps were largest for Procera, yet overall conventional and CAD/CAM copings exhibited comparable fit ranges, confirming the hypothesis.

Abstract

summary : Evaluation of the marginal and internal fit of all‐ceramic molar crown‐copings hypothesizing that Computer Aided Design/Computer Aided Manufacturing (CAD/CAM) fabrication shows the same accuracy of fit as conventional techniques. A set of six individual crown preparations was duplicated 12 times yielding 72 plaster dies. Slip‐cast (In‐Ceram Zirconia ® ), heat‐pressing (Empress II ® ) and CAD/CAM crown‐copings (Cerec inLab ® , DCS ® , Decim ® and Procera ® ) were seated on 12 dies each. Marginal and internal gap width was measured in the SEM at 120× magnification. Marginal gap of slip‐cast (25 ± 18 μ m) was significantly ( P < 0·05) smaller than that of Empress II ® (44 ± 23 μ m) copings. Procera ® (17 ± 16 μ m) and Decim ® (23 ± 17 μ m) did not differ ( P > 0·05) from slip‐cast (25 ± 18 μ m) but were smaller ( P < 0·001/ P < 0·01) than Empress II ® (44 ± 23 μ m) and Cerec inLab ® (43 ± 23 μ m) ( P < 0·001/ P < 0·05). DCS ® (33 ± 20 μ m) did not differ ( P > 0·05) from any of the others. The internal mid‐orobuccal gap width of Procera ® (136 ± 68 μ m) was larger ( P < 0·001) than that of Decim ® (81 ± 30 μ m) and slip‐cast (94 ± 84 μ m) ( P < 0·05) while Empress II ® (105 ± 53 μ m), DCS (110 ± 79 μ m) and Cerec inLab ® (114 ± 58 μ m) did not differ significantly ( P > 0·05) from Decim ® , Procera ® and slip‐cast. Internal mesiodistal gap width was similar. The fit of conventional and CAD/CAM all‐ceramic molar crown‐copings covered the same range of gap width confirming the assumed hypothesis.