Purpose: To compare the marginal fit and internal surface roughness of CAD/CAM zirconia copings milled with 3- and 5-axis milling devices.
Materials And Methods: Forty titanium implant stock abutments (4.8 mm in diameter, 4 mm in height) screwed to dental implants (4.1 mm in diameter) embedded in resin were considered phantoms and included in this in vitro study. All 40 phantoms were scanned with the same intraoral scanner, from which images of the virtual wax-up of zirconia copings were obtained and exported as standard tessellation language (STL) files. From each resulting STL file, two copings were milled: one using a 3-axis milling device, and the other using a 5-axis milling device. After milling, zirconia copings underwent high-speed sintering before being analyzed for marginal fit (ie, marginal gap measurement), and internal surface roughness was assessed with a scanning electron microscope (SEM). Statistical comparisons between groups were assessed with Mann-Whitney test.
Results: Median marginal gap values were 34.80 μm (95% CI: 0.00 to 173.98) for the 5-axis milling device group and 141.97 μm (95% CI: 82.13 to 163.46) for the 3-axis milling device group. A statistically significant difference in marginal gap was found between both milling device groups (P = .039). In addition, qualitative SEM analysis indicated higher internal surface roughness for the 3-axis milling device group.
Conclusion: Within the limitations of this study, the present findings suggest that 5-axis milling devices outperform 3-axis milling devices for milling CAD/CAM zirconia copings from intraoral scans of implant stock abutments.
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http://dx.doi.org/10.11607/ijp.7069 | DOI Listing |
BMC Oral Health
January 2025
Department of Fixed Prosthodontics, Faculty of Dental Medicine, Al-Azhar University, Cairo, 11651, Egypt.
Purpose: The current study aimed to compare modified Polyether-ether-ketone's fracture resistance and failure mode versus lithium disilicate glass-ceramic endocrowns.
Materials And Methods: A total of 16 butt-joint endocrown specimens on mandibular second molar teeth were fabricated and divided into two equivalent groups; Pressable modified Polyether-ether-ketone (PEEK) (BioHPP) and Pressable lithium disilicate glass ceramic (IPS e.max Press).
J Vis Exp
December 2024
School of Engineering and Materials Science, Queen Mary University of London.
J Biomed Mater Res B Appl Biomater
January 2025
Dental Materials Unit, Center for Dental Medicine, Clinic for Masticatory Disorders and Dental Biomaterials, University of Zurich, Zurich, Switzerland.
The purpose of this study was to evaluate the characteristics of the ceramic bonding to cobalt-chromium (Co-Cr) alloys fabricated by casting, milling, and additive manufacturing, compared with zirconia and nickel-chromium. One hundred specimens (N = 100), prepared with the dimensions of 25 × 3 × 0.5 mm, were assigned to five groups (n = 20): presintered milled Co-Cr (Group M), additively manufactured Co-Cr (Group SLM), cast Co-Cr (Group C), presintered zirconia (Group Zi), and cast Ni-Cr (Group Ni).
View Article and Find Full Text PDFBMC Oral Health
January 2025
Faculty of Dentistry, British University in Egypt (BUE), Shorouk, Egypt.
Purpose: This study aimed to compare different treatment modalities to correct ill-fitted maxillary complete denture either by the conventional relining method or by scanning the relining impression and digitally construct a new denture regarding patient satisfaction, denture retention, and adaptation.
Materials And Methods: Twelve edentulous patients suffering from loose maxillary complete dentures were selected, dentures' borders and fitting surfaces were prepared, and relining impressions were taken, the impressions were scanned and the STL files were used for CAD/CAM milling ( computer aided designing/ computer aided manufacturing) of new maxillary dentures (Group A), then the relining impression went through the conventional laboratory steps to fabricate (Group B) maxillary dentures. Both groups were evaluated regarding patient satisfaction by a specially designed questionnaire, retention values were measured by a digital force gauge at denture insertion appointment and two weeks later, geomagic software was used to evaluate dentures adaptation to oral tissues.
J Indian Prosthodont Soc
January 2025
Department of Epidemiology, College of Medicine, University of Cincinnati, Ohio, USA.
Aims: To compare the accuracy of marginal fit of CAD-CAM endocrown with two different preparation forms, i.e., endocrown with ferrule and endocrown without ferrule.
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