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Comparative Study
. 2025 Apr 15;25(1):575.
doi: 10.1186/s12903-025-05947-x.

Marginal and internal adaptation and absolute marginal discrepancy of 3D-printed, milled, and prefabricated crowns for primary molar teeth: an in vitro comparative study

Nagehan Aktaş  1 , Yasemin Akın  2 , Mert Ocak  3 , Didem Atabek  2 , Merve Bankoğlu Güngör  4
Affiliations
Comparative Study

Marginal and internal adaptation and absolute marginal discrepancy of 3D-printed, milled, and prefabricated crowns for primary molar teeth: an in vitro comparative study

Nagehan Aktaş et al. BMC Oral Health. .

Abstract

Background: The quality of marginal and internal adaptation plays a crucial role in the clinical longevity of pediatric crowns. This study aimed to evaluate the effect of restoration type (3D-printed, milled, and prefabricated) on the marginal and internal adaptation and absolute marginal discrepancy (AMD) values of crowns for primary molar teeth.

Methods: Three restoration groups were created: 3D-printed resin, milled resin-matrix ceramic, and prefabricated zirconia crowns (n = 10 per group). A typodont tooth was prepared according to the guidelines for prefabricated zirconia crowns and scanned to design restorations. 3D-printed and milled crowns were fabricated from the same design. All crowns were cemented on standardized 3D-printed resin dies with self-adhesive resin cement. Marginal and internal adaptation and AMD values were evaluated using micro-computed tomography (micro-CT) at multiple measurement points. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey HSD tests, with statistical significance set at P < 0.05.

Results: The restoration type significantly influenced the marginal and internal gap and AMD values (P < 0.05). The prefabricated crown group exhibited the highest marginal gap (233.5 ± 33.4 μm) and internal gap (538.6 ± 47.4 μm). The 3D-printed group showed the highest AMD value (299.5 ± 70.2 μm). The milled group demonstrated the lowest gap values, which remained within clinically acceptable limits.

Conclusions: Prefabricated zirconia crowns displayed the highest marginal and internal gaps, whereas milled crowns exhibited the most favorable adaptation values within clinically acceptable limits. Given their superior adaptation, CAD-CAM-produced restorations may be a recommendable alternative for pediatric patients.

Keywords: 3D-printed crowns; Absolute marginal discrepancy; CAD-CAM restorations; Internal adaptation; Marginal adaptation; Micro-CT analysis; Pediatric dentistry; Prefabricated zirconia crowns; Primary teeth.

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Conflict of interest statement

Declarations. Ethics approval and consent to participate: It is not necessary. Competing interests: The authors declare no competing interests. Consent for publication: Not applicable. Clinical Trial Number: Not applicable.

Figures

Fig. 1
Fig. 1
Sagittal and coronal sections of the Micro-CT images
Fig. 2
Fig. 2
View of the gaps on the Micro-CT image (Arrows are showing the measurement points; M: marginal, A: axial, and O: occlusal)
See this image and copyright information in PMC

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