Effect of surface finishing on marginal adaptation of CAD/CAM crowns

Leen A. Musharbash

Faisal Al-Hussainy

Musharbash, Leen A., Al-Hussainy, Faisal, Conejo, Julian, Anadioti, Eva, Mante, Francis, Markus, Blatz B.
University of Pennsylvania School of Dental Medicine, Department of Preventive and Restorative Sciences


This in-vitro study evaluated the marginal adaptation of ceramic crowns fabricated with a chairside CAD/CAM (computer aided design/computer aided manufacturing) system on preparations with varying surface finish.


Ten maxillary right central incisor acrylic teeth (M300 Series, ACADENTAL) were divided into two groups (Control group CG, Finished group FG) of varying surface finishing preparations (n=5) and prepared for all ceramic crowns with varying bur grits (K0394 Blatz/Conejo: CAD/CAM Preparation System, BRASSELER/USA) under dental loupes with 4.5x magnification (ZEISS EyeMag Smart). The CG & FG were prepared using the medium grit bur (847KR 016). FG was then refined with the fine grit bur (8847KR 016) for two minutes. Preparations were scanned with an intraoral scanner (CEREC Omnicam, Dentsply Sirona) and hybrid ceramic crowns (Enamic, Vita Zahnfabrik) were designed (CEREC software 5.1), milled (CEREC MC XL), hand polished and cemented using a dual cure resin cement system (PANAVIA V5, Kuraray Noritake).Scanning electron microscope (SEM) images were made (Singh Center for Nanotechnology, University of Pennsylvania) with magnification of ×100 (FEI Quanta 600 ESEM; FEI Co) and used to measure the vertical marginal gap.50 measurements were made per tooth: 25 mid-facial margin area and 25 mid-palatal margin area. The data were statistically analyzed (Mann-Whitney Rank Sum Test, P<0.001).


The FG resulted in a significant decrease in the overall mean marginal gap compared to the CG (p<0.001). The mid-facial margin area had a significant decrease in the overall mean marginal gap in comparison to the mid-palatal margin area (p<0.001) of both CG and FG.


Varying surface finish has a significant impact on the marginal gap of all ceramic restorations. Finished preparations have a smaller marginal gap than unfinished preparations for all ceramic restorations. The Mid-Facial Marginal area in both groups has a smaller marginal gap when compared to the mid-palatal margin area.