Flexural Strength of 3D-Printing Resin Materials for Provisional Fixed Dental Prostheses.

The clinical application of 3D-printed provisional restorations is increasing due to expansion of intraoral scanners, easy dental computer-aided design (CAD) software, and improved 3D printing speed. This study compared flexural strength of 3D-printed three-unit fixed dental prostheses with that of conventionally fabricated and milled restorations. A metal jig of two abutments and pontic space and an indenter for flexural strength measurement were fabricated. A three-unit fixed dental prosthesis was designed and manufactured using three additive manufacturing technologies, with subtractive manufacturing and a conventional method as controls. Digital light processing (DLP) group specimens were prepared from a polymethyl methacrylate (PMMA)-based resin and printed with a DLP printer. Stereolithography (SLA) group specimens were prepared from PMMA-based resin and printed with an SLA printer, and fused deposition modeling (FDM) group specimens were from a polylactic acid-based resin and printed with an FDM printer. Flexural strength was investigated using a universal testing machine, and the results were statistically analyzed. DLP and SLA groups had significantly higher flexural strength than the conventional group (p < 0.001). No significant difference was observed in flexural strength between DLP and SLA groups. The FDM group showed only dents but no fracture. The results of this study suggest that provisional restorations fabricated by DLP and SLA technologies provide adequate flexural strength for dental use.

Evaluating the Minimal Specimens From Endoscopic Ultrasound-Guided Fine-Needle Aspiration in Pancreatic Masses.

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has become one of the most useful diagnostic modalities for the diagnosis of pancreatic mass. The aim of this study was to investigate the role of analyzing the minimal specimens obtained by EUS-FNA for the diagnosis of solid masses of pancreas.This study consisted of retrospective and prospective analyses. The retrospective study was performed on 116 patients who underwent EUS-FNA of solid masses for cytological smear, histological analysis, and combined analysis including immunohistochemical (IHC) staining. In the prospective study, 79 patients were enrolled to evaluate the quality and accuracy of EUS-FNA histological analysis and feasibility of IHC staining.The final diagnoses of all patients included pancreatic cancer (n = 126), nonpancreatic cancer (n = 21), other neoplasm (n = 27), and benign lesions (n = 21). In our retrospective study, the combined analysis was more sensitive than cytological analysis alone (P < 0.01). The overall sensitivity of cytology, histology, and combined analysis was 69.8%, 67.2%, and 81.8%, respectively. In the prospective analysis, 64.2% of all punctures were helpful for determining the diagnosis and 40.7% provided sufficient tissue for IHC staining. Histological analysis was helpful for diagnosis in 74.7% of patients. IHC staining was necessary for a definite diagnosis in 11.4% of patients, especially in the cases of nonmalignant pancreatic mass.Histological analysis and IHC study of EUS-FNA specimens was useful for the accurate diagnosis of pancreatic and peripancreatic lesions. Combined analysis showed significantly higher sensitivity than cytology alone because IHC staining was helpful for a diagnosis in some patients.

Clinicopathologic characteristics of 29 invasive carcinomas arising in 178 pancreatic mucinous cystic neoplasms with ovarian-type stroma: implications for management and prognosis.

Information on the clinicopathologic characteristics of invasive carcinomas arising from mucinous cystic neoplasms (MCNs) is limited, because in many early studies they were lumped and analyzed together with noninvasive MCNs. Even more importantly, many of the largest prior studies did not require ovarian-type stroma (OTS) for diagnosis. We analyzed 178 MCNs, all strictly defined by the presence of OTS, 98% of which occurred in perimenopausal women (mean age, 47 y) and arose in the distal pancreas. Twenty-nine (16%) patients had associated invasive carcinoma, and all were female with a mean age of 53. Invasion was far more common in tumors with grossly visible intracystic papillary nodule formation ≥1.0 cm (79.3% vs. 8.7%, P=0.000) as well as in larger tumors (mean cyst size: 9.4 vs. 5.4 cm, P=0.006); only 4/29 (14%) invasive carcinomas occurred in tumors that were <5 cm; however, none were <3 cm. Increased serum CA19-9 level (>37 U/L) was also more common in the invasive tumors (64% vs. 23%, P=0.011). Most invasive carcinomas (79%) were of tubular type, and the remainder (5 cases) were mostly undifferentiated carcinoma (2, with osteoclast-like giant cells), except for 1 with papillary features. Interestingly, there were no colloid carcinomas; 2 patients had nodal metastasis at the time of diagnosis, and both died of disease at 10 and 35 months, respectively. While noninvasive MCNs had an excellent prognosis (100% at 5 y), tumors with invasion often had an aggressive clinical course with 3- and 5-year survival rates of 44% and 26%, respectively (P=0.000). The pT2 (>2 cm) invasive tumors had a worse prognosis than pT1 (≤2 cm) tumors (P=0.000), albeit 3 patients with T1a (<0.5 cm) disease also died of disease. In conclusion, invasive carcinomas are seen in 16% of MCNs and are mostly of tubular (pancreatobiliary) type; colloid carcinoma is not seen in MCNs. Serum CA19-9 is often higher in invasive carcinomas, and invasion is typically seen in OTS-depleted areas with lower progesterone receptor expression. Invasion is not seen in small tumors (<3 cm) and those lacking intracystic papillary (mural) nodules of ≥1 cm, thus making the current branch-duct intraductal papillary mucinous neoplasm management protocols also applicable to MCNs.

Prognostic significance of ATM and cyclin B1 in pancreatic neuroendocrine tumor.

Ataxia telangiectasia mutated kinase (ATM) and cyclin B1 are involved in cell cycle control. The prognostic significance of both molecules has not yet been investigated in pancreatic neuroendocrine tumors. The aim of this study was to evaluate the clinical and prognostic significance of ATM and cyclin B1 in patients with pancreatic neuroendocrine tumors. A total of 107 pancreatic neuroendocrine tumor specimens that were surgically resected were immunohistochemically investigated using the tissue microarray technique. Clinicopathologic results and survival were evaluated retrospectively. High expression of ATM and cyclin B1 was related to well-differentiated endocrine tumors of the World Health Organization (WHO) classification, but not related to TNM stages. The high ATM expression group (ATM ≥ 4) had a significantly smaller tumor size, lower recurrence rate, more number of functioning tumor, and well differentiation of WHO classification. The high cyclin B1 expression group (cyclin B1 ≥ 5) was related to smaller tumor size, less vascular invasion, less recurrence rate, and less death rate. However, cyclin B1 was the only significant factor for survival following multivariate analysis (p = 0.008; OR, 0.54; 95 % CI, 0.35-0.85). The current results suggested that expression of ATM and cyclin B1 may be useful markers to identify patients with poor prognosis who may benefit from close follow-up and aggressive therapy in pancreatic neuroendocrine tumors.

A prospective comparison of liquid-based cytology and traditional smear cytology in pancreatic endoscopic ultrasound-guided fine needle aspiration.

OBJECTIVE: To compare results of liquid-based cytology (LBC) and the conventional smear method (SMEAR) when performing endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for lesions of suspected pancreatic malignancy without an on-site cytopathologist. STUDY DESIGN: Fifty-eight patients were prospectively enrolled between July and December 2009. Aspirates obtained from the first needle pass were randomized either to SMEAR or LBC. Another sample from the second needle pass was allocated to the other method. The rest of the aspirates from the third or later needle passes were used for SMEAR. Diagnostic accuracy was compared and related factors were pursued. RESULTS: Although both methods were 100% specific, LBC was inferior to SMEAR in terms of sensitivity, negative predictive value, and accuracy. However, LBC provided correct diagnoses in 2 out of 3 cases of false negatives for malignancy by SMEAR in which blood was highly contaminated. Although no factor was identified for LBC, low blood contamination and more than 3 needle passes were related with accurate diagnosis in SMEAR. CONCLUSION: LBC was less accurate than SMEAR when performing pancreatic EUS-FNA without an on-site cytopathologist. However, LBC might serve as a good complement to SMEAR if blood contamination is profound.

Oncogenic anaplastic lymphoma kinase (ALK) mutation in neuroblastomas and other pediatric tumors.

Neuroblastoma (NB) is one of the most common malignant pediatric tumors that show aggressive behavior. Most advanced-stage NBs have proven refractory to many treatment modalities, and a fundamental alternative therapy, such as inhibition of biological pathways, is now being explored. Anaplastic lymphoma kinase (ALK) has recently been identified as an activation mutation in familial or high-risk sporadic NBs. We examined the prevalence of the ALK mutation in 54 NB cases (23 pre-treatment cases and 31 cases for which specimens were available before and after treatment) and the presence of the ALK mutation in various pediatric tumors. We detected the ALK mutation (F1174C and R1275Q) in 2 (3.7%) of the 54 NB specimens. Both cases showed poorly differentiated and advanced-stage NBs. No ALK mutations were detected in other pediatric tumors. The frequency of the ALK mutation was somewhat lower than that expected in Korean patients with NBs. The mutation detected in the present study was one of the hotspot mutations, including positions of F1174 and R1275 reported previously. The results of the present study suggest the possibility of potential roles of ALK inhibitors in the therapeutics of a small population of neuroblastoma carrying mutated ALK kinases.

Preoperative evaluation of the longitudinal extent of borderline resectable hilar cholangiocarcinoma by intraductal ultrasonography.

BACKGROUND AND AIM: In patients with hilar cholangiocarcinoma (HC), longitudinal tumor extent is important for curative resection. The purpose of this study was to evaluate the longitudinal extents of HC using transpapillary intraductal ultrasonography (IDUS) for optimal surgical planning. METHODS: From July 2006 to April 2010, a total of 42 patients with borderline resectable HC were enrolled at Samsung Medical Center, a tertiary referral hospital in Seoul, Korea. All patients were evaluated using multi-detector computed tomography (MDCT), endoscopic retrograde cholangiopancreatography (ERCP) and IDUS. The new modified Bismuth Type (MBT) classification, in which the traditional Bismuth type IV stage is divided into stages IVa and IVb, was used to determine whether the tumor invaded the left lateral section. Among the subtypes of HC, the periductal infiltrative type (PDI) and intraductal papillary neoplasm of the bile duct (IPN-B) were compared. The accuracies of CT, ERCP, and IDUS were assessed through comparison with the postoperative histology findings. RESULTS: A total of 42 patients were prospectively enrolled, and the tumor extent could be assessed histologically in 30 patients. The accuracies of CT, ERCP, and IDUS were 66.6%, 60%, and 90%, respectively. The accuracy of IDUS was 85.7% in 21 patients with PDI and 100% in nine patients with IPN-B. CONCLUSIONS: Hilar cholangiocarcinoma staging based on IDUS findings was highly accurate. We therefore highly recommend using IDUS for optimal surgical planning in patients with borderline resectable HC.