Biomedical subjects
W H Steen
Publications and source records attributed to W H Steen.
A positioning device for the edentulous mandible in extraoral radiography.
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Cavernous hemangioma of the optic disc.
Cavernous hemangioma of the optic disc and retina is a vascular hamartoma composed of clusters of thin-walled saccular aneurysms partially filled with dark venous blood. It is now considered a neuro-oculo-cutaneous syndrome whose mode of inheritance is probably autosomal dominant. This report describes a cavernous hemangioma of the optic disc in a patient without skin or neurological findings. Its clinical appearance, generally benign ocular nature, and occasional association with central nervous system or cutaneous lesions is emphasized.
Granular cell tumor (myoblastoma) of the orbit.
A 43-year-old woman had a three-month history of increasing proptosis and visual loss secondary to an inferior orbital mass. Surgical exploration revealed an encapsulated mass that was excised with good visual recovery. Light microscopy as well as electron microscopy confirmed the diagnosis of granular cell myoblastoma. The tumor's location within the orbit was unusual and its histologic origin was uncertain.
Distribution of missing teeth and tooth morphology in patients with oligodontia.
In a population of 196 patients with isolated oligodontia (/I) and oligodontia as part of a syndrome (/S), the distribution of missing teeth was recorded. Patients with oligodontia/S were missing significantly more teeth than patients with oligodontia/I.
A three-dimensional finite element study on two versus four implants in an edentulous mandible.
The difference in stress distribution in the bone around dental implants was determined under conditions where either two or four implants were placed in the interforaminal region of the mandible. The purpose was also to determine the influence of the height of the mandible on the stress distribution. The stress distribution around the implants was investigated using three-dimensional finite element models of the interforaminal region of two mandibles with two different stages of resorption. It was concluded that there is no reduction of the extreme principal stresses when the load is distributed over an increasing number of implants. There is a tendency for a gradual stress increase as mandibular height decreases.