International Journal of Chemical and Biochemical Sciences (ISSN 2226-9614)[/vc_column_text][/vc_column][/vc_row]
VOLUME 29(23) (2026)
3D-Printed versus Milled Resin Nanoceramic Restorations: A Narrative Review of Marginal Adaptation, Fracture Resistance, and Clinical Implications
Kareem Abdelfattah Ahmed Mohamed AbouelNeel*, Kamal Khaled Ebeid,
Nancy Essam Bahig Rafla
1*,2,3 Fixed Prosthodontics Department, Faculty of Dentistry, Ain Shams University, Cairo, Egypt
Abstract
The past two decades have seen CAD/CAM reshape fixed prosthodontics around two competing fabrication methods: subtractive milling and 3D printing. Resin nanoceramic materials — hybrid composites that sit between ceramics and composites in mechanical behavior — are now used in both workflows, yet the comparative evidence on their clinical performance remains thin. This narrative review synthesizes the published literature comparing milled and 3D-printed resin nanoceramic restorations with respect to marginal adaptation, fracture resistance, failure mode, and clinical implications. A structured search was conducted in PubMed/MEDLINE, Scopus, and Web of Science (2009–2024) using predefined MeSH terms and free-text keywords. Milled restorations consistently achieve smaller marginal gaps (65–115 µm) than 3D-printed equivalents (90–130 µm), though both remain within the clinically accepted 150 µm thresholds. Thermocycling increases marginal gaps in both groups, with thinner 3D-printed designs showing greater susceptibility. Fracture resistance exceeds clinically relevant posterior occlusal loads in both groups; milled restorations generally demonstrate higher fracture loads, though pooled data show no statistically significant overall difference. Failure modes are predominantly mixed in both groups. Under controlled laboratory conditions, both methods perform adequately. 3D-printed restorations look especially promising for conservative overlay designs, though strict post-processing, sound adhesive technique, and long-term clinical trials are still needed before they can be broadly recommended.
Keywords: 3D-Printing; CAD/CAM; fracture resistance; marginal adaptation; resin nanoceramic
Full length article *Corresponding Author, e-mail: drkareemabdelfattah@gmail.com, Doi # https://doi.org/10.62877/21-IJCBS-26-29-23-21
Submitted: 23-05-2026; Accepted: 25-06-2026; Published: 30-06-2026