The physical mechanisms of ultrasound, namely cavitation and acoustic streaming, generated by the Enac-Osada ultrasonic unit were investigated for effectiveness in disrupting Streptococcus mitis. In addition, the bactericidal effect of ultrasound in the presence of 2.5% sodium hypochlorite was examined. Bacterial suspensions were irradiated directly with ultrasound in simulated root canals, and the viability of bacteria was examined after growth on a blood agar medium under anaerobic conditions at 37 degrees C for 5 days. The results indicated that ultrasound per se failed to disrupt bacteria but resulted in increases in the viable counts; the former was considered to be because of the lack of cavitation and the latter because of the dispersal effects of acoustic streaming. The 2.5% sodium hypochlorite solution demonstrated powerful bactericidal activity.
Zygomycosis is an uncommon polymorphic fungal disease. One clinical subtype, nasofacial zygomycosis, is caused by infectious exposure to the organism Conidiobolus coronatus. A case affecting the nose and lips of a 42-year-old Malay man is reported here. The clinicopathologic features and management of this disease are described, and its differential diagnosis is discussed.
This report details a case of mandibular peripheral ameloblastoma having a clear cell component. The latter consisted of ovoid cells with vacuolated or clear cytoplasm and vesicular or pyknotic nuclei that may be disposed as discrete clusters or show direct transition from typical acanthomatous areas. Comparison of this lesion with other odontogenic and nonodontogenic tumors that contain clear cells is discussed in the context of the differential diagnosis.
Plexiform granular cell odontogenic tumor of the mandible has recently been described. The cardinal histopathologic feature, as its name suggests, is a monophasic plexiform pattern of granular cells; the principal tumor in the differential diagnosis is granular cell ameloblastoma. Unlike the two previously reported cases of plexiform granular cell odontogenic tumor, which occurred as solid tumors in elderly men, the lesion reported here is a unicystic variant occurring in a middle-aged woman.
Two hundred four cases of fibrous lesions of the gingiva were studied histologically for the presence of calcified tissue, the nature of the connective tissue, the type of keratinization, and the degree of epithelial thickness. Initially these lesions were subcategorized into four specific entities, namely fibrous epulis, fibroepithelial polyp, calcifying fibroblastic granuloma, and ossifying fibrous epulis. It was found that 46.5% of the lesions contained calcifications. The connective tissue was represented predominantly by either the collagenous type (50.5%) or the mixed (cellular and collagenous) type (44.6%). It was also found that 36% of the lesions were ulcerated, and, of these, 79.5% were associated with the cellular type of connective tissue and calcifications. In an attempt to subcategorize the fibrous lesions into specific entities, it was found that 32 cases (15.7%) had mixed features. This fact supports the suggestion that these lesions are stages in the spectrum of a single disease process and should collectively be termed fibroblastic gingival lesions. However, it is also suggested that the two terms, namely peripheral fibroma and fibrous epulis with and without ossification, should be retained whereas the usage of other terminologies should be avoided.
The dorsal skin of 18 healthy Sprague-Dawley rats was used to investigate the reaction of connective tissue to buffered and unbuffered glutaraldehyde. Both the agents produced well-circumscribed lesions that underwent resolution within 30 days. Observation also shows that 2.0% buffered and unbuffered glutaraldehyde maintained a relatively inflammation-free status in connective tissue.