Surface Roughness, Bond Strength And Hardness Of 3D-Printed Resins Fabricated By Different Vat Polymerization Techniques
Dr. İrem Beril Yesil, Dr. Nursena Oztemel, Assoc. Prof. Almira Ada Diken Turksayar
Biruni University
Objectives
The aim of this study was to evaluate the surface roughness (Ra), shear bond strength (SBS), and Vickers hardness (VHN) of 3D-printed resins fabricated by different vat polymerization techniques.
Materials and Methods
40 disk-shaped specimens (Ø10×2-mm) were divided into four groups; 3D-printed resins (Stereolithography; SLA and Digital Light Processing; DLP and Liquid Crystal Display; LCD) and milled polymethylmethacrylate (Ivory CAD, MP) (n=10). After polishing all specimens with 600-800-1000 grit abrasive papers, the Ra was measured by using a non-contact profilometer. Composite resin was then applied to the specimen surface using a polytetrafluoroethylene mold. All specimens were then thermocycled. (5-55°C, 5000 cycles). SBS was measured using a universal testing machine at a crosshead speed of 1 mm/min. VHN measurements were then performed. The data obtained were analyzed using 1-way ANOVA test followed by Tukey HSD for Ra and Vickers hardness values, while Tamhane’s T2 tests were used for SBS values (a=.05).
Results
There was a significant difference between the groups in terms of SBS (p=0.02) and VH (p<0.001) while Ra (p=0.148) values were nonsignificant. Ra was above the clinically acceptable threshold of 0.2 μm in all groups. DLP (68.90 MPa) and LCD (70.63 MPa) specimens had higher and similar SBS (p= 1.000) while MP (46.23) specimens had statistically lower SBS. DLP (33.87) had higher VH than all groups (p<0.01) other than SLA (P=.831), while MP (21.75) had lower VH than all groups (p<0.01) other than LCD (24.94) (P=.143).
Conclusions
The SBS and VHN of 3D-printed resins were affected by different vat polymerization techniques. In terms of SBS and VHN, 3D-printed resins fabricated by the DLP technique were more successful. Additional surface treatments are required to reduce the Ra values in all of the milled and printed specimens.