Marginal and internal fit of crowns based on additive or subtractive manufacturing

Abstract

Objective To assess the marginal and internal fit of crowns manufactured by additive and subtractive manufacturing technique. Materials and Methods Twenty extracted teeth prepared for complete coverage crowns were scanned with an intra-oral scanner (Omnicam, DentsplySirona). For the subtractive manufacturing (SM) group, ten crowns were manufactured in a hybrid resin block (Vita Enamic, Vita Zahnfabrik). For the additive manufacturing (AM) group, the crowns were manufactured in a hybrid resin material (NextDent C&B, 3D systems). The design parameters were identical for the two groups. The marginal and internal fit (determined at the axial wall, the cusp tip and occlusally) was assessed before cementation with the replica technique and after cementation under stereomicroscope after sectioning of the crowned teeth. Results For the SM group, the marginal fit was 91 µm (±28 µm) before cementation and 85 µm (±18 µm) after cementation. In the AM group, the marginal fit was 75 µm (±29 µm) before cementation and 71 µm (±18 µm) after cementation. The differences were not statistically significant. As regards the internal fit, the fit at the axial wall was statistically significantly better in the SM group than in the AM group ( p =.009 before cementation and .03 after cementation). Occlusally the fit in the AM group was significantly better than in the SM group after cementation ( p <.001). Conclusion Within the limitations of the current study, the marginal fit of additively manufactured crowns is comparable to crowns manufactured with chair-side subtractive technique and within the clinically acceptable range. As regards the internal fit no one technique was consistently superior.

Effect of Printing Layer Thickness on the Trueness and Margin Quality of 3D-Printed Interim Dental Crowns

“…Considering the effect of the layer thickness on trueness at thin surfaces such as crown margins [30], high layer thickness may be expected to result in low trueness, which was confirmed by lower trueness and marginal quality found with the 100 µm group in the present study. Although a previous study has shown that the marginal fit of 3D-printed crowns is within a clinically acceptable range, and that there is no difference between 3D-printed and milled crowns [38], significant differences in the margin quality were found in the present study. The marginal quality in the present study was evaluated by a 3-point scale instead of absolute values, indicating worse margin quality of the 3D-printed crowns irrespective of the layer thickness.…”

Effect of Different CAD/CAM Milling and 3D Printing Digital Fabrication Techniques on the Accuracy of PMMA Working Models and Vertical Marginal Fit of PMMA Provisional Dental Prosthesis: An In Vitro Study

“…This result was in agreement with the studies performed by Haddadi et al [ 67 ], who found that there is no statistically significant difference in the value of the vertical marginal gap between the provisional crowns fabricated by milling and those fabricated by 3D printing. They concluded that 3D printing could effectively replace milling in the fabrication of provisional restorations.…”

Printable and Machinable Dental Restorative Composites for CAD/CAM Application—Comparison of Mechanical Properties, Fractographic, Texture and Fractal Dimension Analysis

“…This manufacturing method is commonly used for the manufacturing of metal frameworks, templates, temporary restorations, splints, and removable prostheses [ 1 , 4 ]. The marginal fit of 3D printed restorations is comparable with the fit of the milled ones [ 7 ]. Thanks to the continuous development of light-curing resin composite materials, it is now possible to print adhesively cemented permanent single-tooth restorations [ 8 ].…”