Master’s Degree Awarded to Researcher Abdullah Ameen Abdullah Al-Mekhlafi in Dentistry

Researcher Abdullah Ameen Abdullah Al-Mekhlafi was awarded a Master’s Degree in Dentistry ‎for his thesis titled: Comparative Analysis of Marginal Fitness in Metal Copings Fabricated by Lost Wax and 3D Printing: In Vitro Study, which was submitted to the Department of Conservative Dentistry, Faculty of Dentistry– Sana’a University. The MA defense was held on Monday, August 10, 2026‎‎.
The MA Viva-voce Committee, which was formed based on a resolution issued by the Graduate Studies and Scientific Research Council, consisted of the following:
# Committee Members Designation Position
1 Dr. Mohammed Abdulaziz Mansour Al-Baili Internal Examiner Chair
2 Assoc. Prof. Mohsen Ali Yahya Al-Hamzi Main Supervisor Member
3 Assoc. Prof. Mohammed Al-Samhari External Examiner Member

The study aimed to evaluate and compare the marginal adaptation of metal frameworks fabricated using the conventional lost-wax technique and selective laser melting (SLM), as well as assess the effect of finish-line thickness on marginal adaptation.
The study examined the importance of marginal adaptation as a key factor affecting the clinical success and longevity of fixed dental prostheses. Poor marginal adaptation may increase the risk of microleakage, luting cement dissolution, and secondary caries, in addition to complications affecting periodontal tissue health. The study also investigated the potential of modern digital manufacturing technologies, particularly selective laser melting, as a promising alternative to the conventional lost-wax technique.
For the study methodology, a mandibular first molar was prepared according to the principles of full-crown preparation and digitally scanned to produce 40 identical resin models. The samples were divided into two experimental groups: the first comprised 20 samples fabricated using the lost-wax technique, while the second comprised 20 samples fabricated using selective laser melting.
After the metal frameworks were cemented, the samples were sectioned using the cross-sectional method. The marginal gap was then measured at eight predetermined points for each sample using a stereomicroscope and digital image analysis software. Statistical analysis was performed using the Mann–Whitney U, Kruskal–Wallis, and Tukey post-hoc tests at a statistical significance level of (p ≤ 0.05).
The study produced several key findings, most notably a statistically significant difference in marginal adaptation between the two fabrication methods (p < 0.001). The median marginal gap was 34.79 micrometers in the lost-wax group, compared with 24.53 micrometers in the selective laser melting group, indicating better marginal adaptation in the frameworks fabricated using selective laser melting. The findings also showed statistically significant differences between buccal and lingual measurements in both study groups, in addition to an effect of finish-line thickness on marginal adaptation. The study concluded that, within the limitations of this laboratory study, metal frameworks fabricated using selective laser melting (SLM) demonstrated significantly better marginal adaptation than those fabricated using the conventional lost-wax technique. Although differences in marginal adaptation were observed between the two methods, all recorded marginal-gap values were within clinically acceptable limits. The findings also confirmed an effect of finish-line thickness on marginal adaptation. The defense session was attended by a number of academics, researchers, students, and interested participants, as well as the researcher’s colleagues and family members. [gallery ids="52646"] https://youtu.be/HLGWXdwNyaM