Properties of dual-curable luting composites polymerized with single and dual curing modes.

The purpose of this study was to evaluate the influence of visible-light exposure on water absorption, solubility and colour stability of dual-curable luting composites. Using eight dual-curable luting composites (2bond2, Bistite II, G-CERA Cosmotech II, Imperva Dual, Linkmax, Lute-It, Panavia Fluoro Cement and Variolink II), disk specimens were prepared by the following two methods: (i) dual-cured specimens; exposed with visible-light from a light-curing unit, and (ii) chemical-cured specimens; chemically polymerized without exposure. Five specimens were produced for each material and curing mode. Water absorption and solubility were determined according to standardized testing methods, and the data were compared using analysis of variance (ANOVA) and contrasts. With regard to colour stability, the colour difference (DeltaE*) values between 24 h and the other immersion periods (1, 2, 3, 4, 8, 12, 16, 20 and 24 weeks) were calculated and then analysed by repeated measure ANOVA. The dual-cured specimens exhibited significantly lower solubility values than the chemical-cured specimens except for the Lute-It material. The dual-cured Linkmax material exhibited the lowest solubility (0.51 +/- 0.01 microg mm(-3)) and the lowest DeltaE* value after 24 weeks (2.64 +/- 0.39). The dual-curable luting composites should be light-exposed after seating of restorations in order to reduce water absorption and solubility, and to improve colour stability.

In vitro evaluation of the cytocompatibility of a glass-lonomer cement sealer.

The purpose of this study was to evaluate the cytocompatibility of two different types of root canal sealers in cell culture. Human periodontal ligament cells were cultured with set materials from an experimental glass-ionomer cement sealer (KT-308) and a commercially available zinc oxide-eugenol-based sealer (Canals) for 1, 3, and 7 days. Cytotoxic effects were evaluated from the morphological changes under a light microscope. Canals induced severe degenerative alteration of human periodontal ligament cells. In contrast, human periodontal ligament cells adjacent to KT-308 showed normal morphology and growth during the culture period. These results suggest that the glass-ionomer cement sealer, KT-308, is cytocompatible and has good potential as a root canal sealer.

Influence of visible-light exposure on colour stability of current dual-curable luting composites.

This study was conducted to evaluate influence of visible-light exposure on colour stability of dual-curable luting composite. Using six dual-curable luting composites [Bistite II (BI), Clapearl DC (CL), Dicor Light Activated Cement (DI), G-Cera Cosmotech II (GC), Lute-It (LU) and Variolink II (VA), disk specimens were prepared with the following two methods: (i) dual-cured specimens, exposure with visible-light from a photo-curing unit for 120 s and (ii) chemical-cured specimens, chemically cured without exposure. Five specimens were produced for each material and curing mode. After 24 h, all specimens were immersed in distilled water at 37 degrees C for 24 weeks, during which colour accuracy was measured with a dental colorimeter. The colours characterized in the Commission Internationale d'Eclairage (CIE) L*a*b* colour space were first determined 24 h after preparation (baseline colour evaluation), and again after 1, 2, 3, 4, 8, 12, 16 and 24 weeks. The colour difference (Delta E*) values between 24 h and the other immersion periods were calculated, and then analysed by repeated measure analysis of variance (ANOVA). In addition, the Delta E* values after 24 weeks for dual-cured specimens were compared with those for chemical-cured specimens by one-way ANOVA and by contrasts for each composite (P < 0.05). The Delta E* values were influenced by the material and curing mode as well as immersion period (P=0.0001). After 24 weeks the dual-cured specimens showed significantly lower Delta E* values than the chemical-cured specimens, except for the VA material. The CL material exhibited the least colour change (1.9 +/- 0.2) among the dual-cured specimens, and the VA material showed the least (4.5 +/- 0.9) among the chemical-cured specimens after 24 weeks. Dual-curable luting composites should be polymerized with the dual modes to ensure colour stability.

Colour reproducibility of a photo-activated prosthetic composite with different thicknesses.

This study determined the colour accuracy of a photo-activated prosthetic composite with various thicknesses and shades for the purpose of evaluating the relationship between material thickness variation and colour reproducibility. Four light shades (A1, B1, C1 and D2) and four dark shades (A4, B4, C4 and D4) of a representative photo-activated prosthetic composite (Artglass) for body paste were assessed. The specimens were prepared with thicknesses of 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mm. The L*a*b* colour parameter of each shade was measured using a dental colorimeter (ShadeEye) connected to a computer. The overall colour accuracy of groups of five specimens was compared by means of analysis of variance (ANOVA) and Scheffe's S multiple range test (P=0;05). In addition, L*a*b* colour difference (Delta E*) values between the 3.0 mm thickness and the other thicknesses were calculated. Three-factor ANOVA revealed that all colour parameters were influenced by the thickness as well as by the shade letter and shade tab (P < 0.05). The L* value consistently decreased for all shades as thickness increased, although there was no obvious correlation between the thickness of the material and either the a* or b* values. Among the Delta E* values, the values between the 2.5 and 3.0 mm thicknesses were the lowest, and values were found to be lower than 2.0 for all shades. The colour accuracy of the photo-activated prosthetic composite was related to the thickness of the material regardless of the shade. For acceptable colour reproducibility, a composite material thickness of at least 2.5 mm was found to be required.

[An epidemiologic examination on the prevalence of the periodontal diseases and oral pigmentation in Yusho patients in 2000].

An epidemiologic examination was carried out to reveal the prevalence of the periodontal diseases and oral pigmentation in patients with Yusho in 2000. The results obtained were as follows. 1) 63 patients out of 69 patients with Yusho, who were measured periodontal pocket depth according to Ramfjord' methods, had at least one tooth with periodontal pocket deeper than 3 mm. Similarly, 188 teeth out of a total 285 examined teeth showed periodontal pocket with more than 3 mm depth. 2) In this examination, intraoral sinus tracts stoma were observed in 9 patients out of 70 patients. Radiographic examination and probing examination of pocket depth indicated that periapical lesions were involved in these intraoral sinus tract formation. 3) Oral pigmentation was observed in 46 out of 76 patients with Yusho. In this study, gingival pigmentation was most predominant among oral pigmentation. These results indicated that PCBs had yet affected the mechanism of oral pigmentation and metabolism of alveolar bone.

Curing depth of different shades of a photo-activated prosthetic composite material.

This study determined the depth of cure of different shades of a prosthetic composite material with the aim of evaluating the influence of shade variation on post-curing material properties. Four light shades having small tabs (A1, B1, C1 and D2) and four dark shades having higher tabs (A4, B4, C4 and D4) of a prosthetic composite (Artglass) for body paste based on the Vita Lumin Shade guide were selected. Specimens of each shade were exposed with the proprietary photo-curing unit (UniXS) for periods 20, 30, 60 and 90 s. The curing depth of the material for each shade was determined with a scraping technique described by the International Organization for Standardization (ISO 4049), and average values of groups of five specimens were compared using analysis of variance (ANOVA) and Scheffe's S intervals (P < 0.05). The L*a*b* colour parameters of five specimens after 90 s exposure were measured using a small-area dental colorimeter (ShadeEye) in order to determine the colorimetric differences. Three-factor ANOVA revealed that the depth of cure was influenced by shade letter (A, B, C or D) and shade tab (1 and 2, or 4) as well as by the exposure period (P=0.05). Curing depth of the light shades was consistently greater than that of the dark shades. Among the eight shades selected, B1 shade demonstrated the greatest curing depth, while A4 shade exhibited the lowest curing depth. For all shades, longer exposure increased the depth of cure. All of the light shades exhibited higher L* values than any of the four dark shades. Curing depth of the composite material was found to be related to the Vita shade variation and the exposure period.

Simple technique for pancreatogastrostomy and the histological findings of pancreatogastric anastomosis.

The leakage of pancreatic juice is the most serious complication after pancreatoduodenectomy. In an attempt to lessen the incidence of this complication, we have developed a simple technique for the anastomosis of pancreatogastrostomy. Since March 14, 1995, we have already performed surgical procedures on 8 cases of pancreatogastrostomy using this technique and as yet have never experienced fatal complications. We report the autopsy findings of pancreatogastric anastomosis histologically. The specimen taken from the anastomosis reveals good mucosal continuity. This result suggests the importance of reliable sutures between the pancreatic parenchyma and the full thickness of the gastric wall for the anastomosis of pancreatogastrostomy.

Angiogenesis inhibitor TNP-470 prevents implanted liver metastases after partial hepatectomy in an experimental model without impairing wound healing.

The ability of the angiogenesis inhibitor TNP-470 to prevent liver metastasis after partial hepatectomy, and whether TNP-470 impairs liver regeneration or skin wound healing, was evaluated. Following the injection of VX2 carcinoma cells into the portal vein of rabbits, half of the animals underwent resection of the middle hepatic lobe (hepatectomized group) and half did not (non-hepatectomized group). TNP-470 (50 mg) was infused continuously into the portal vein in both groups for 7 days, while controls received only water. The hepatectomized TNP-470-treated group had significantly fewer tumours (mean(s.e.m.) 23.3(12.3)) than the hepatectomized control group (123.7(24.4)). There was no significant difference in the 5-bromo-2'-deoxyuridine labelling index of regenerated hepatocytes between the TNP-470-treated and control groups. Wound healing in TNP-470-treated animals was not impaired. Intraportal infusion of TNP-470 prevents the recurrence of liver metastasis after partial hepatectomy without impairing healing or liver regeneration.

[Effects of angiogenesis inhibitor TNP-470 to suppress the recurrence in the liver remnant after partial hepatectomy for liver metastases in rabbits].

We investigated the effects of an angiogenesis inhibitor, TNP-470, in suppressing the recurrence in the liver remnant after partial hepatectomy for VX2 liver metastases model of rabbits. After inoculation of 1 x 10(6) VX2 tumor cells via the portal vein, the medial lobe of the liver was resected. Then, TNP-470 (7 mg/body/day) was infused (Group 1), or distilled water (Group 2), continuously via the mesenteric vein for a week. The control group received only infused distilled water via the mesenteric vein. Fourteen days after the tumor inoculation, there were 66.0 +/- 20.2 (mean +/- SD) metastatic colonies on the liver surface of control group, against 23.3 +/- 24.0 and 123.7 +/- 47.9 colonies in Group 1 and Group 2, respectively. There were significant differences between control group and Group 2, and between Group 1 and Group 2. We consider that the liver regeneration following hepatectomy might provoke tumor growth of occult metastases in the liver remnants. TNP-470 suppressed these growth by its anti-neovascular activity. And this effect reduced the number of metastatic colonies. Fourteen days after hepatectomy, the weights of the liver were no different among 3 groups. The BrdU Labeling Index was also no different between Group 1 and Group 2. TNP-470 did not suppress the regeneration of the liver remnant. We consider that the systemic side effects of TNP-470 might be made minimal, because this agent affects only on endothelial cells. These results suggest that the angiogenesis inhibitor TNP-470 is beneficial to suppress hepatic recurrence after partial hepatectomy for liver metastases without suppression of liver regeneration.

Intra-arterial administration of the angiogenesis inhibitor TNP-470 blocks liver metastasis in a rabbit model.

We evaluated the best route of administration of TNP-470, an angiogenesis inhibitor, by comparing the anti-tumour effects and toxicity following injection via the hepatic artery, the portal vein, or the jugular vein in a rabbit model of liver metastases. Following the injections of 1 x 10(6) VX2 carcinoma cells into the portal vein of rabbits, 50 mg of TNP-470 was injected continuously into the hepatic artery, portal vein, or jugular vein for 7 days. The number of tumours on the surface of the liver was counted 14 days following the start of the infusion, and the serum glutamic-oxaloacetic transamine (GOT), glutamic-pyruvic transaminase (GPT) and total bilirubin concentrations were examined. In addition, a coloured silicon rubber was injected into the vessels of the liver to visualise the capillary networks around the tumours and assess the degree of suppression of angiogenesis by TNP-470. The mean number of tumours following intra-arterial injection (17.5 +/- 2.9) was significantly less than the control (237.0 +/- 34.0) (P < 0.05). The mean numbers of the tumours following intraportal (89.1 +/- 16.0) and intravenous (140.6 +/- 31.2) injection were both less than the controls (215.3 +/- 45.5, 284.8 +/- 55.4 respectively), but the differences were not significant. We conclude that intra-arterial injection of TNP-470 is the most effective method for preventing liver metastases in this model.

[Inhibition of liver metastases in rabbits by arterial infusion of angiogenesis inhibitor, TNP-470].

We examined the prevention of liver metastases by arterial infusion of the angiogenesis inhibitor, TNP-470, in Japanese White Rabbits; 1.0 x 10(6) of VX2 carcinoma cells were injected into the mesenteric vein for tumor inoculation. Then the rabbits were divided into the following two groups. Group 1: 2 ml of distilled water was continuously injected into the common hepatic artery of control for 7 days. Group 2: 50 mg of TNP-470 solved in 2 ml of distilled water was continuously administered into the common hepatic artery for 7 days. On day 14, the number of metastases on each liver surface was counted. The mean number of metastases were 237.0 +/- 133.26 and 24.4 +/- 15.05 in Group 1 and 2, respectively. There was a significant difference between the two groups (p < 0.05). We found no side effects of TNP-470 such as body weight loss or liver disfunction. Microphil was injected into the common hepatic artery to observe the neovasculature. The proliferation of tumor vessels was suppressed in Group 2. We considered that arterial infusion of TNP-470 is effective to prevent liver metastases, because the blood supply to liver metastases is well developed from the hepatic artery, and TNP-470 is directly effective on the endothelium itself, and inhibits neovascularization.

[Recurrence and survival rate of advanced gastric cancer after preoperative EAP-II intra-arterial infusion therapy].

Ninety-eight patients with advanced gastric cancers underwent gastrectomy from Jan. 1989 to Dec. 1991. For these patients, preoperative intra-arterial injection therapy using EAP-II (etoposide 100 mg, epirubicin 20 mg, carboplatin 100 mg) was given to 24 patients. In this report, the recurrence and survival rate of these patients were investigated. After curative resection, the survival rate of patients with EAP-II 36 months after operation was 76.9%, while that of patients without EAP-II was 78.6%. There were no significant differences between these two groups. Two peritoneal carcinomatoses and two liver metastases were seen in patients with EAP-II (recurrence rate, 30.7%). Eight recurrences were observed in patients without preoperative injection therapy (peritoneal dissemination, 4; local recurrence, 3; lymph node recurrence, 1). Previously, we reported that drugs were remarkably accumulated in gastric cancer tissue and regional lymph nodes after EAP-II intra-arterial injection therapy. This high accumulation might cause no local or lymph node recurrence was seen in patient with EAP-II. Thus, it was concluded that preoperative EAP-II intra-arterial injection may prevent local and lymph node recurrences, and that further study of the combination and dose of anti-cancer drug needed to improve the postoperative survival rate in advanced gastric cancer patients.

[Intermittent intra-arterial infusion chemotherapy of 5-FU and carboplatin for unresectable liver metastases].

Intermittent intra-arterial infusion chemotherapy (5-FU: 500 mg and carboplatin; 100 mg per week) using an implantable access was performed for 19 patients with unresectable liver metastasis of colon cancer (17 cases) and gastric cancer (2 cases). Survival time ranged from 12 to 641 days, and the average was 281.4 days with 50% survival at 276 days. Of 19 cases, one access was infected, two cases had catheter obstruction, and two cases had nausea and vomiting.