ULTRASONIC INVESTIGATION OF THE EYE WITH A NEW CONTACT METHOD AND WITH THREE DIFFERENT REAL‐TIME PRESENTATIONS
The ultrasound examination was carried out by means of a crystal with a 40° sector scan, which was pressed either against the eyelid or directly against the sclera. The real‐time display was obtained by either A‐mode, B‐mode or combined A/B‐mode scanning. In clinical applications, both the resolution capacity and the sensitivity of the device were good. A‐mode scanning gave the greatest accurary in amplitude measurement, while the A/B‐mode yielded the most concrete topographic picture of the target.
DIAGNOSTICS OF DETACHMENT OF THE RETINA BY MEANS OF ULTRASOUND
It is usually easy to diagnose detachment of the retina by means of ophthalmoscopy. On the other hand, it is at times difficult and even impossible to establish whether the detachment is idiopathic or produced by inflammation, tumour or trauma. From the point of view of therapy it is most important to know whether or not there is any tumour tissue behind the detached retina, which, nevertheless, is frequently most uncertain in spite of the use of the ophthalmoscope, transillumination and radioactive phosphorus. Mundth and Hughes (3) as well as Oksala and Lehtinen (4) have recurred to the use of ultrasound in the diagnostics of tumours within the eye. Oksala and Lehtinen were moreover successful in registering the echo of a detached retina with the aid of an ultrasonic equipment, thus being able to establish whether there was fluid (vitreous or blood) or tumour tissue behind the retina. The investigators just mentioned succeeded, solely by the use of this equipment, in determining the localisation of the detachment of retina with an accuracy of some two millimetres. Since the ultrasound easily penetrates both the transparent and the opaque lens, it is possible to determine, by means of an ultrasonic equipment, the site of the retina even in those cases in which we fail to see the eye ground through the ophthalmoscope for some reason. Simultaneously one can say, with a relatively high degree of certitude, whether there is tumour tissue behind the detached retina or not. Since our search of the literature has failed to reveal any reports on the use of ultrasound in the diagnostics of such cases, we describe below a case of our own.
Influence of filler addition, storage medium and evaluation time on biaxial flexure strength and modulus of adhesive systems
Abstract Objective. This study evaluated the effects of filler addition, storage medium and time on biaxial flexural strength and flexural modulus of six adhesive systems. Materials and methods. The adhesives were either unfilled resins: Single Bond, Prime&Bond 2.1 and One-Step; or filled resins: Single Bond Plus, Prime&Bond NT and One-Step Plus. Resin discs of each product (0.5 mm thick × 6.0 mm diameter) were prepared using silicon molds (n = 10). The discs were stored dry, in water, mineral oil or ethanol for 1 week or 3 months before biaxial flexural testing. Data were statistically analyzed by 3-way ANOVA and Tukey's post-hoc test (α = 0.05). The specimens were tested in a universal testing machine at 1.27 mm/min until failure occurred. Results. In general, the storage in ethanol led to significantly lower flexural strength and flexural modulus values than the other storage conditions for all adhesives in both storage periods. Filler addition increased flexural strength and flexural modulus for Prime&Bond NT, when it was stored dry or in water for 1 week. For Single Bond Plus, the filler addition resulted in higher flexural modulus, when it was stored for 1 week in oil and in ethanol. No significant differences in flexural modulus were observed between One-Step and One-Step Plus in any storage medium. Conclusions. Results suggested that filler addition does not necessarily have to increase the flexural strength and flexural modulus. Ethanol and oil storages tended to yield opposite effects.