Chemical composition, surface roughness, and ceramic bond strength of additively manufactured cobalt-chromium dental alloys.

STATEMENT OF PROBLEM: Selective laser melting (SLM) additive manufacturing (AM) technology is a current option to fabricate cobalt-chromium (Co-Cr) metal frameworks for dental prostheses. However, the Co-Cr alloy composition, surface roughness, and ceramic bond strength values that SLM metals can obtain are not well-defined. PURPOSE: The purpose of this in vitro study was to compare the chemical composition, surface roughness, and ceramic shear bond strength of the milled and SLM Co-Cr dental alloys. MATERIAL AND METHODS: A total of 50 disks of 5 mm in diameter and 1 mm in thickness were fabricated by using subtractive (control group) and AM with each of following SLM providers: SLM-1 (EOS), SLM-2 (3D systems), and SLM-3 (Concept Laser). The milled disks were airborne-particle abraded with 100-µm aluminum oxide particles. All the specimens were cleaned before surface roughness (Ra), weight (Wt%), and atomic (At%) percentages were analyzed. Three-dimensional profilometry was used to analyze the topographical properties of the surface parameters Ra (mean surface roughness). The chemical composition of Co-Cr alloy specimens was determined by using energy dispersive X-ray (EDAX) elemental analysis in a scanning electron microscope (SEM). Thereafter, the specimens were bonded to a ceramic (Dentine A3 and Enamel S-59; Creation CC) interface. Specimens were stored for 24 hours at 23 °C. The bond strength of the SLM-ceramic interface was measured by using the macroshear test (SBT) method (n=10). Adhesion tests were performed in a universal testing machine (1 mm/min). The Shapiro-Wilk test revealed that the chemical composition data were not normally distributed. Therefore, the atomic (At%) and weight percentages (Wt%) were analyzed by using the Kruskal-Wallis test, followed by pairwise Mann-Whitney U tests between the control and AM groups (AM-1 to AM-4). However, the Shapiro-Wilk test revealed that the surface roughness (Ra) and ceramic bond strength data were normally distributed. Therefore, data were analyzed by using 1-way ANOVA, followed by the post hoc Sidak test (α=.05). RESULTS: Significant differences were obtained in Wt%, At%, and Ra values among the Co-Cr alloys evaluated (P<.05). Furthermore, the control group revealed significantly lower mean ±standard deviation Ra values (0.79 ±0.11 µm), followed by AM-3 (1.57 ±0.15 µm), AM-2 (1.80 ±0.43 µm), AM-1 (2.43 ±0.34 µm), and AM-4 (2.84 ±0.27 µm). However, no significant differences were obtained in the metal-ceramic shear bond strength among the different groups evaluated, ranging from mean ±standard deviation 75.77 ±11.92 MPa to 83.65 ±12.21 MPa. CONCLUSIONS: Co-Cr dental alloys demonstrated a significant difference in their chemical compositions. Subtractive and additive manufacturing procedures demonstrated a significant influence on the surface roughness of the Co-Cr alloy specimens. However, the metal-ceramic shear bond strength of Co-Cr alloys was found to be independent of the manufacturing process.

Atypical Enostoses-Series of Ten Cases and Literature Review.

Bone islands (BI; enostoses) may be solitary or occur in the setting of osteopoikilosis (multiple bone islands) and are sometimes associated with Gardner's Syndrome (osteopoikilosis and colonic polyposis). Characteristic features of bone islands are (1) absence of pain or local tenderness, (2) typical radio dense central appearance with peripheral radiating spicules (rose thorn), (3) Mean CT (computerized tomography) attenuation values above 885 Hounsfield units (HU) (4) absence of uptake on bone scan and (5) radiographic stability over time. However, when enostoses display atypical features of pain, unusual radiographic appearance, aberrant HU, increased radiotracer uptake, and/or enlargement, they can be difficult to differentiate from more sinister bony lesions such as osteoblastic metastasis, low grade central osteosarcoma, osteoid osteoma and osteoblastoma. In this retrospective case series, the demographic, clinical, radiographic, treatment and outcome for ten patients with eleven atypical bone islands (ABI) are presented, some showing associated pain (5), some with atypical radiographic appearance (3), some with increased activity on BS (4), some with documented enlargement over time (7), one with abnormal CT attenuation value, some in the setting of osteopoikilosis (2), one in the setting of Gardner's Syndrome and one osteoid osteoma simulating a bone island. This series represents the spectrum of presentations of ABI. Comprehensive review of the literature reveals that the previous largest series of ABI showing enlargement as the atypical feature was in younger patients with jaw BI. Hence, this represents one of the largest series reported of ABI of all types in adults.

Primary Ewing sarcoma of the adrenal gland: A rare cause of abdominal mass.

Ewing sarcoma is a malignant tumor that more commonly affects the long bones. Primary Ewing sarcoma of the adrenal gland is a rare diagnosis. We report an unusual case of primary Ewing sarcoma of the adrenal gland in a 34-year-old man who initially presented with abdominal as well as flank pain and abdominal mass. Computed tomography and magnetic resonance imaging showed a heterogeneous, hemorrhagic right adrenal mass with inferior vena cava extension and thrombosis. Thus, a major open surgery including right adrenalectomy, right nephrectomy, inferior vena cava thrombectomy with resection, and a retroperitoneal lymph node dissection was necessitated. Early recognition with radiological imaging and treatment of extraosseous Ewing sarcoma of the adrenal gland with a multimodality approach reduces morbidity and mortality.

Experiences with the Mass Distribution of LPG Stoves in Rural Communities of Ghana.

Household air pollution (HAP) is a leading cause of morbidity and mortality worldwide. To limit HAP exposure and environmental degradation from biomass fuel use, the Government of Ghana promotes liquefied petroleum gas (LPG) use in rural Ghana via the Rural LPG program (RLP). We assessed the experiences of the RLP in 2015, 2 years after its launch. A mixed methods approach was used involving Focus Group Discussions (19) and in-depth interviews (25). In addition, a survey questionnaire was administered to elicit socio-demographic characteristics, household cooking practices and stove use patterns of 200 randomly selected respondents. At about 9 months after LPG acquisition, < 5% of LPG beneficiaries used their stoves. Some of the reasons ascribed to the low usage of the LPG cookstoves were financial constraints, distance to LPG filling point and fear of burns. Community members appreciate the convenience of using LPG. Our results underscore a need for innovative funding mechanisms contextualized within an overall economic empowerment of rural folks to encourage sustained LPG use. It emphasizes the need for innovative accessibility interventions. This could include establishing new LPG filling stations in RLP beneficiary districts to overcome the barriers to sustained LPG use.

Biliary-Pleural Fistula following Portal Vein Embolization for Perihilar Cholangiocarcinoma.

Biliary-pleural fistula (BPF), an abnormal communication between the biliary tract and pleural space, is a rare but potentially life-threatening complication following percutaneous biliary intervention. We report a case of BPF following portal vein embolization (PVE) in a 79-year-old woman with obstructive jaundice secondary to perihilar cholangiocarcinoma. The patient successfully underwent right-sided PVE; however, the patient developed a symptomatic right-sided bilious pleural effusion the following day. Despite aggressive drainage of the pleural effusion with a large-bore chest tube and maximal medical management, the patient died from respiratory failure and pneumonia. Although rare, knowledge of this complication is important when performing PVE in patients with biliary obstruction because it can be life-threatening. Early recognition and management of this complication are crucial to avoid a poor outcome.

Müllerian Remnant Cyst as a Cause of Acute Abdomen in a Female Patient with Müllerian Agenesis: Radiologic and Pathologic Findings.

We report a case of a 17-year-old female with Müllerian agenesis who presented with right sided abdominal pain clinically suspicious for acute appendicitis. Multimodality imaging workup revealed a heterogeneous cystic right upper quadrant mass with surrounding fluid and inflammatory changes. Surgical resection of this mass was performed and a histopathologic diagnosis of a hemorrhagic Müllerian remnant cyst was made, which to the best of our knowledge has never been described in a patient with Müllerian agenesis.

P53 nuclear stabilization is associated with FHIT loss and younger age of onset in squamous cell carcinoma of oral tongue.

BACKGROUND: Squamous cell carcinoma of tongue (SCCT) is expected to harbor unique clinico-pathological and molecular genetic features since a significant proportion of patients are young and exhibit no association with tobacco or alcohol. METHODS: We determined P53, epidermal growth factor receptor, microsatellite instability, human papilloma virus infection and loss of heterozygosity status at several tumor suppressor loci in one hundred and twenty one oral SCCT (SSCOT) samples and analyzed their association with clinico-pathological features and patient survival. RESULTS: Our results revealed a significantly higher incidence of p53 nuclear stabilization in early (as against late) onset SCCOT. FHIT loss was significantly associated with p53 nuclear stabilization and the association was stronger in patients with no history of tobacco use. Samples harboring mutation in p53 DNA binding domain or exhibiting p53 nuclear stabilization, were significantly associated with poor survival. CONCLUSION: Our study has therefore identified distinct features in SCCOT tumorigenesis with respect to age and tobacco exposure and revealed possible prognostic utility of p53.

Detection of retinal changes in Parkinson's disease with spectral-domain optical coherence tomography.

PURPOSE: This pilot study investigated whether high-resolution spectral-domain optical coherence tomography (SD-OCT) could detect differences in inner retinal layer (IRL), peripapillary retinal nerve fiber layer (RNFL), and macular thickness between patients with Parkinson's disease (PD) and controls. METHODS: Both eyes of patients with PD and age-matched controls were imaged with the Heidelberg Spectralis(®) HRA + OCT. RNFL, IRL, and macular thickness were measured for each eye using Heidelberg software. These measurements were compared with validated, published normal values for macular and RNFL thickness, and compared with matched controls for IRL thickness. RESULTS: Eighteen eyes from nine subjects with PD and 19 eyes of 16 control subjects were evaluated using SD-OCT. The average age of PD patients was 64 years with a range of 52-75 years. The average age of controls was 67 years with a range of 50-81 years. No significant reduction in IRL thickness was detected between PD patients and age-matched controls at 13 points along a 6 mm horizontal section through the fovea. No significant difference in RNFL thickness was detected between PD patients and published normal values. Overall average RNFL thickness was 97 µm for PD patients, which exactly matched the normative database value. However, significant differences in macular thickness were detected in three of nine subfields between PD subjects and published normal values. In PD subjects, the outer superior subfield was 2.8% thinner (P = 0.026), while the outer nasal and inner inferior subfields were 2.8% (P = 0.016) and 2.7% (P = 0.001) thicker compared to published normal values. CONCLUSION: In this pilot study, significant differences in macular thickness were detected in three of nine subfields by SD-OCT. However, SD-OCT did not detect significant reductions in peripapillary RNFL and IRL thickness between PD patients and controls. This suggests that macular thickness measurements by SD-OCT may potentially be used as an objective, noninvasive, and easily quantifiable in vivo biomarker in PD. Larger, longitudinal studies are needed to explore these relationships further.