Accuracy of Dental Replica Models Using Photopolymer Materials in Additive Manufacturing: In Vitro Three-Dimensional Evaluation.

PURPOSE: To evaluate the accuracy (trueness and precision) of dental replica models produced by using photopolymer materials in additive manufacturing. MATERIALS AND METHODS: A complete arch model was scanned using an extraoral scanner (Identica Blue) and established as reference. For the control group, 10 stone models were acquired through the conventional method from the reference model. For the experimental groups, digital data were acquired using an intraoral scanner (CEREC Omnicam), and 10 stereolithographic apparatus (SLA) models and 10 PolyJet models were made. All models were scanned with an extraoral scanner. Three-dimensional analysis software was used to measure differences between the 3D scanned images in root mean square values. The ISO-5725-1 specification was followed to measure trueness and precision between two 3D scanned data. Trueness was calculated by overlapping scanned data with the reference model and precision by performing pairwise intragroup comparisons. Also the ratio of region out of tolerance (> ±50 µm) was measured. One-way ANOVA and Tukey's post hoc analysis were applied. RESULTS: There was no statistically significant difference in trueness between the stone and the SLA models (p > 0.05). Dental replica models using photopolymer materials showed statistically significantly better precision than that of the stone model (p < 0.05). Regarding tolerance, no statistically significant difference was observed between the stone and the SLA models (p > 0.05). CONCLUSIONS: Although the dental replica models using photopolymer materials did not show better trueness than the conventional stone models, there was no significant difference between the SLA and the stone models. Concerning precision, dental replica models using photopolymer materials presented better results than that of the conventional stone models. In sum, dental replica models using photopolymer materials showed sufficient accuracy for clinical use.

Accuracy (trueness and precision) of dental models fabricated using additive manufacturing methods.

OBJECTIVE: This study evaluated the accuracy (trueness and precision) of dental models fabricated using additive manufacturing (AM) methods such as PolyJet and fused deposition modeling (FDM). MATERIALS AND METHODS: 10 stone models were acquired for the control group by scanning a complete arch model. For the experimental groups, 10 PolyJet models and 10 FDM models were fabricated from digital impressions using an intraoral scanner. All 30 models were then scanned, and root mean square values were measured using three-dimensional (3D) analysis software. RESULTS: Trueness did not significantly differ between the stone and PolyJet models. The precision of the AM models was significantly higher than that of the stone models. The layer thicknesses of the FDM models were greater than those of the PolyJet models. CONCLUSION: The results of this study show that it might be possible for the dental models fabricated using additive manufacturing methods to be used in clinical settings.

The effect of poly(ADP-ribosyl)ation inhibition on the porcine cumulus-oocyte complex during in vitro maturation.

Poly(ADP-ribosyl)ation (PARylation) plays important roles in DNA repair, apoptosis, transcriptional regulation, and cell death, and occurs via the activity of poly(ADP-ribose) polymerases (PARPs). Previous studies have shown that PARylation affects mouse and porcine pre-implantation development and participates in mechanisms of autophagy. However, there have not yet been reported the role of PARylation during in vitro maturation (IVM) of porcine oocytes. Thus, we investigated the effect of PARylation inhibition on this process; cumulus-oocyte complexes (COCs) were cultured with 3-aminobenzamide (3-ABA, PARP inhibitor) during porcine IVM. Full cumulus expansion was significantly reduced (10.34 ± 1.23 [3-ABA] vs. 48.17 ± 2.03% [control]), but nuclear maturation rates were not changed in the 3-ABA treatment group. Especially, we observed that cumulus cells were little expanded after 22 h in 3-ABA treated COCs. The mRNA expression levels of oocyte maturation- and cumulus expansion-related genes were evaluated at 22 and 44 h. GDF9, BMP15, COX-2, and PTX3 expression were upregulated at 44 h, whereas the levels of HAS2 and TNFAIP6 were downregulated in the 3-ABA treated group. Furthermore, 3-ABA treatment significantly decreased the developmental rate (28.24 ± 1.06 vs. 40.24 ± 3.03%) and total cell number (41.12 ± 2.10 vs. 50.38 ± 2.27), but increased the total apoptotic index (6.44 ± 0.81 vs. 3.08 ± 0.51) in parthenogenetically activated embryos. In conclusion, these results showed that PARylation regulates cumulus expansion through the regulation of gene expression and affects developmental competence and quality in parthenogenetic embryos.

Sirtuin inhibition leads to autophagy and apoptosis in porcine preimplantation blastocysts.

Sirtuins are nicotinamide adenine dinucleotide dependent class III histone deacetylase proteins that play a crucial role in several cellular processes, including DNA repair, apoptosis, and lifespan. Previous studies have shown that sirtuin inhibition leads to embryonic developmental arrest and oxidative stress in porcine and murine. However, sirtuin-mediated mechanisms have not been examined in porcine preimplantation blastocysts. We therefore investigated the relationship between sirtuins and autophagy. Embryos were cultured with 100 µM sirtinol (SIRT1/2 inhibitor) in NCSU-23 media after in vitro fertilization. Treatment with sirtinol significantly reduced the rates of morula (21.34 ± 1.84 vs. 11.89 ± 2.01), blastocyst development (17.18 ± 1.81 vs. 9.00 ± 2.02), and total cell number (50.80 ± 1.47 vs. 37.71 ± 1.79), compared to controls, with an associating decrease the levels of Sirt2 transcript. Sirtinol treatment induced autophagy through an increase in LC3 transcript and LC3 protein. BECLIN1 and ATG5 expression showed a slight increase in treated group. Finally, treatment with sirtinol dramatically increased TUNEL indices (6.55 ± 0.84 vs. 11.44 ± 0.81) and fragmentation indices (0.33 ± 0.05 vs. 1.40 ± 0.30). BCL2L1 expression was lower, while Caspase-3 expression was significantly elevated in the sirtinol-treated group. Therefore, these findings suggest that sirtuins may elicit their effects through modifying autophagy and apoptosis, leading to developmental arrest and reducing the quality of porcine preimplantation embryos.