Lung mineral fibers of former miners and millers from Thetford-Mines and asbestos regions: a comparative study of fiber concentration and dimension

Fiber dimension and concentration may vary substantially between two necropsy populations of former chrysotile miners and millers of Thetford-Mines and Asbestos regions. This possibility could explain, at least in part, the higher incidence of respiratory diseases among workers from Thetford-Mines than among workers from the Asbestos region. The authors used a transmission electron microscope, equipped with an x-ray energy-dispersive spectrometer, to analyze lung mineral fibers of 86 subjects from the two mining regions and to classify fiber sizes into three categories. The most consistent difference was the higher concentration of tremolite in lung tissues of workers from Thetford-Mines, compared with workers from the Asbestos region. Amosite and crocidolite were also detected in lung tissues of several workers from the Asbestos region. No consistent and biologically important difference was found for fiber dimension; therefore, fiber dimension does not seem to be a factor that accounts for the difference in incidence of respiratory diseases between the two groups. The greater incidence of respiratory diseases among workers of Thetford-Mines can be explained by the fact that they had greater exposure to fibers than did workers at the Asbestos region. Among the mineral fibers studied, retention of tremolite fibers was most apparent.     

Mineralogy of lung tissue in dental laboratory technicians' pneumoconiosis.

This article reports on a case of pneumoconiosis in a dental laboratory technician with a history of respiratory exposure to dental materials. Special attention is paid to the mineralogical analysis of the lung biopsy. The abundance of chromium, cobalt, and silica particles suggests that the dental technician's pneumoconiosis is the result of the combined effects of hard metal dusts and silica particles generated during finishing dental frameworks. Adequate technical protection such as a local ventilation system should be considered in dental laboratories to prevent respiratory exposure of dental technicians to airborne contaminants.     

Extension of Pindborg tumor to the maxillary sinus: a case report

The calcifying epithelial odontogenic tumor is a benign epithelial odontogenic lesion that accounts for less than 1% of all odontogenic tumors. It is most frequently seen in the posterior areas of the mandible. Extension of this lesion to the maxillary sinus is extremely rare. In this paper, we report the fourth of such cases which has been reported, up to now. This tumor was encased between the right maxillary lateral and canine roots with extension to the maxillary sinus. Histologically, the tumor is composed of sheets of epithelial cells with eosinophilic or clear cytoplasm, intercellular bridges, nuclear pleomorphism, but no mitotic figures, amorphous eosinophilic and calcified materials were seen within the sheets of epithelial cells.     

Presence of Visceral Larva Migrans in the Urinary Bladder of a Woman in Khorramabad,Iran

The presence of Visceral Larva Migrans (VLM) in a patient is reported. A 57-year- old woman suffering from right upper abdominal and suprapubic pain referred into a clinic in Khorramabad, Lorestan Province, Iran. A cystoscopy was performed and biopsy was taken. The light microscopic study showed a couple of larvae as well as mononuclear inflammatory cell- infiltration. Because occurrence of VLM is potentially problem in rural areas, it is recommended that an educational program to be initiated to prevent and control VLM infection in both rural and urban people. Clinicians also should consider the clinical features of visceral larva migrans.     

On the Morphological Deviation in Additive Manufacturing of Porous Ti6Al4V Scaffold: A Design Consideration

Additively manufactured Ti scaffolds have been used for bone replacement and orthopaedic applications. In these applications, both morphological and mechanical properties are important for their in vivo performance. Additively manufactured Ti6Al4V triply periodic minimal surface (TPMS) scaffolds with diamond and gyroid structures are known to have high stiffness and high osseointegration properties, respectively. However, morphological deviations between the as-designed and as-built types of these scaffolds have not been studied before. In this study, the morphological and mechanical properties of diamond and gyroid scaffolds at macro and microscales were examined. The results demonstrated that the mean printed strut thickness was greater than the designed target value. For diamond scaffolds, the deviation increased from 7.5 μm (2.5% excess) for vertical struts to 105.4 μm (35.1% excess) for horizontal struts. For the gyroid design, the corresponding deviations were larger, ranging from 12.6 μm (4.2% excess) to 198.6 μm (66.2% excess). The mean printed pore size was less than the designed target value. For diamonds, the deviation of the mean pore size from the designed value increased from 33.1 μm (−3.0% excess) for vertical struts to 92.8 μm (−8.4% excess) for horizontal struts. The corresponding deviation for gyroids was larger, ranging from 23.8 μm (−3.0% excess) to 168.7 μm (−21.1% excess). Compressive Young’s modulus of the bulk sample, gyroid and diamond scaffolds was calculated to be 35.8 GPa, 6.81 GPa and 7.59 GPa, respectively, via the global compression method. The corresponding yield strength of the samples was measured to be 1012, 108 and 134 MPa. Average microhardness and Young’s modulus from α and β phases of Ti6Al4V from scaffold struts were calculated to be 4.1 GPa and 131 GPa, respectively. The extracted morphology and mechanical properties in this study could help understand the deviation between the as-design and as-built matrices, which could help develop a design compensation strategy before the fabrication of the scaffolds.     

Keratocystic odontogenic tumor: a 10-year retrospective study of 83 cases in an Iranian population

A retrospective analysis was conducted on patients diagnosed with and treated for keratocystic odontogenic tumor (KCOT) at Mashhad School of Dentistry between 1996 and 2006. The patients comprised 44 men and 30 women with a mean age of 27.08 years. Among the total of 83 lesions, 56 (67.5%) occurred in the mandible and 27 (32.5%) in the maxilla. Swelling tended to be the most common complaint (45.8%), while 24.1% of the lesions were diagnosed incidentally. Six patients (8.1%) with a total of 15 lesions had nevoid basal cell carcinoma syndrome; 28 lesions (33.7%) were associated with an impacted tooth, and 12 (14.5%) presented daughter cysts. Sixty-six KCOTs were treated by enucleation [5 recurrences (7.6%)], 6 by marsupialization [2 recurrences (33.3%)] and 11 by marsupialization followed by enucleation (no recurrences). KCOTs in the mandible showed a higher recurrence rate than those in the maxilla (10.7% vs 3.7%). Although the demographics of Iranian patients are closely similar to those of other nationalities, in this series KCOTs tended to develop in younger patients with a peak in teenagers. The posterior region of the mandible showed the highest likelihood of KCOT occurrence and recurrence. Marsupialization followed by enucleation resulted in the lowest recurrence rate.