Effect of photopolymerization variables on composite hardness

STATEMENT OF PROBLEM: Variations in light-polymerizing parameters, such as light intensity and light-to-material distance, may affect the physical characteristics of polymerized resin. PURPOSE: The purpose of this study was to characterize the relation between total light energy and the final hardness of 4 composites polymerized under varying conditions. MATERIAL AND METHODS: Four commercial composite restorative resins (Z100, Filtek A110, Tetric Ceram, and Tetric Flow) were used to prepare 4 disk-shaped specimens (6 x 2 mm) for each experimental condition. Photoactivation was carried out with a light device and energy of 22.6, 15.7, 9.0, or 6.7 J/cm(2). Either the light-to-material distance (0, 5, 10, 15 mm) or activation time (40, 28, 16, 12 seconds) was varied. Immediately after polymerization, Barcol hardness was determined on the specimen surface that had been exposed to the light. Analysis of variance (P<.05) and regression analysis were used to examine the data. RESULTS: No significance (P>.05) was found for the overall effect of the experimental variables (polymerization time and distance), but significant differences (P<.01) were found among materials and energy levels. Regression equations for each product and polymerization condition were calculated for hardness as a function of energy. No significant differences were found for slopes within each material. Hardness values were 3.0 to 3.5 for Tetric Ceram, Tetric Flow, and Filtek A110 and approximately 4.9 for Z100. CONCLUSION: The hardness of the products analyzed was related to the total energy used for activation. The effect was independent of the manner in which the amount of energy was modified (light-to-material distance or activation time).     

Clinicopathological features and CD57 expression in renal cell carcinoma in acquired cystic disease of the kidneys: with special emphasis on a relation to the duration of haemodialysis,the degree of calcium oxalate deposition,histological type,and possible tumorigenesis

Enoki Y, Katoh G, Okabe H & Yanagisawa A
(2010) Histopathology 56, 384–394 Clinicopathological features and CD57 expression in renal cell carcinoma in acquired cystic disease of the kidneys: with special emphasis on a relation to the duration of haemodialysis, the degree of calcium oxalate deposition, histological type, and possible tumorigenesis Aims: Acquired cystic disease of the kidney (ACDK) in patients undergoing haemodialysis is known to develop into renal cell carcinoma (RCC), but its pathogenesis remains unclear. The aims were to analyse the histological findings of ACDK‐RCC and to determine its histogenesis. Methods and results: Twenty‐nine RCCs in 23 patients with ACDK were classified into three groups according to the duration of haemodialysis and were analysed for histological type, calcium oxalate (Oxa) deposition, and cyst and atypical cyst (AC) formation. Histologically, 21 tumours were ACDK‐RCC and eight were clear cell carcinoma (CCC). The ratio of ACDK‐RCC and the numbers of cysts and ACs increased as the duration of haemodialysis was prolonged. The degrees of intratumoral Oxa deposition and cyst and AC formation of ACDK‐RCCs were higher than those of CCCs (Oxa, P = 0.028; cyst, P < 0.0001; AC, P = 0.0002). Many ACDK‐RCCs (85.7%) and some CCCs (50%) had characteristics of the thin ascending loop of Henle as assessed by CD57 (HNK‐1) expression, which was rarely expressed in the 29 control cases. Conclusions: ACDK‐RCCs reveal characteristics of Henle’s loop, which may be related to their peculiar pathological features, including intratumoral oxalate deposition and cyst and AC formation.     

The cancer patient with severe mucositis

Oropharyngeal mucositis is a painful, often dose-limiting side effect of both radiotherapy and chemotherapy. To reduce the intensity of pain and prevent systemic infection via the compromised mucosa, agents such as antiseptic mouthwashes, anti-ulcer compounds, sodium bicarbonate, saline, and allopurinol have been traditionally used with limited success. The new agents that show promise are granulocyte macrophage colony-stimulating factor (GMCSF) and granulocyte colony-stimulating factor (G-CSF). However, best results, dosage, and means of administration still have to be determined. Other agents such as sucralfate, tretinoin, glutamine, and misoprostol are also being tested. The results reported from different testing centers are often contradictory and confusing. Basic requirements in prevention and control of mucositis are good oral hygiene, mechanical débridement of the oral tissues, and hydration.     

Vasoconstricting effect of angiotensin II in human hand veins: influence of aging, diabetes mellitus and hypertension.

We examined human hand veins to determine whether venoconstricting response to angiotensin II (Ang II) and noradrenaline (NA) was influenced by aging or such diseases as diabetes mellitus (DM) and hypertension (HT). Twenty healthy male subjects (20-73 years), and 8 male patients with non-insulin-dependent DM and 8 male patients with essential HT were included in this study. A constant dose (50 ng/min) of Ang II or increasing dose (2-256 ng/min) of NA was infused into the dorsal hand vein and its diameter was measured using a linear variable differential transformer. The constant infusion of Ang II caused rapid desensitization or tachyphylaxis. The venoconstriction by Ang II in the 8 elderly subjects (58 to 73 years) was significantly (p<0.05) larger than that in the 8 young subjects (20 to 36 years) from 6 to 18 min after the start of the infusion (after 6 min: 63.6+/-11.6 (mean+/-SD)% vs. 39.9+/-20.8%, 12 min: 34.0+/-11.9% vs. 12.0+/-12.0%). However, the venoconstriction by Ang II in the patients with DM or HT was not significantly different from that in the 9 age-matched control subjects. No significant difference in venoconstrictor response to NA was observed between the young and elderly subjects, nor between the control subjects and the patients with DM or HT. These findings indicated that venoconstrictor response to Ang II might be greater in the elderly but might not be influenced by DM nor HT.     

Dental treatment of a patient with Friedreich's ataxia

The dental treatment of a patient with Friedreich's ataxia is discussed. Despite the patient's systemic conditions, treatment including oral hygiene instructions and an extraction was performed without complications. With knowledge of this disease, in conjunction with medical consultation, these patients can be treated successfully.