Hydrolysis of functional monomers in a single-bottle self-etching primer--correlation of 13C NMR and TEM findings.

Self-etching primers/adhesives that combine acidic methacrylate monomers with water in a single bottle are hydrolytically unstable and require refrigeration to extend their shelf-lives. This study tested the null hypothesis that one year of intermittent refrigeration of a 4-MET-containing simplified self-etching primer does not result in hydrolytic changes that are identifiable by transmission electron microscopy and (13)C NMR spectroscopy. Human dentin was bonded with UniFil Bond immediately after being unpacked, or after one year of intermittent refrigeration at 4 degrees C. Fresh and aged primers were analyzed by NMR for chemical changes. Ultrastructural observations indicated that there was an augmentation in etching capacity of the aged adhesive that was not accompanied by resin infiltration or effective polymerization. New NMR peaks detected from the aged ethanol-based primer confirmed that degradation occurred initially via esterification with ethanol, followed by hydrolysis of both ester groups in the 4-MET. Hydrolysis of functional methacrylate monomers occurs despite intermittent refrigeration.

Intratumoural expression of thymidylate synthase is an independent predictor of prognosis in patients with squamous cell carcinoma of the tongue: results from a retrospective study.

The aim of this study was to assess the importance of immunohistochemical thymidylate synthase (TS) expression level as a prognostic marker in tongue cancer patients. In 140 patients with primary squamous cell carcinoma (SCC) of the tongue, intratumoural TS expression was evaluated by immunohistochemistry. The level of TS expression was determined by a semiquantitative scoring system, ranging from 1+ to 3+ according to the ratio of TS-positive cells. Of 140 patients, 64 (45.7%), 49 (35.0%) and 27 (19.3%) were assessed as 1+, 2+ and 3+, respectively. Univariate analyses demonstrated that both disease-free survival (DFS) and overall survival (OS) were significantly lower in patients with a TS 3+ tumour than in those with a TS 1+/2+ tumour (DFS: P = 0.0082, OS: P = 0.0100). In a multivariate analysis using the Cox regression model, cervical lymph-node status and TS expression level were selected as independent factors for DFS and OS. Maintenance adjuvant chemotherapy by oral 5-fluorouracil (5-FU) significantly improved DFS and OS in patients with a TS 1+/2+ tumour (DFS: P = 0.0027, OS: P = 0.0398). These data suggest that the level of immunohistochemical TS expression is an independent prognosticator in patients with tongue SCC, and may be useful in the selection of patients who would benefit from oral 5-FU adjuvant chemotherapy.

Water concentration in self-etching primers affects their aggressiveness and bonding efficacy to dentin.

Water is required to ionize acid resin monomers for demineralization of tooth substrates. We tested the null hypothesis that altering the water concentration in two-step self-etching primers has no effect on their aggressiveness and bonding efficacy to dentin. Five experimental self-etching primers were prepared with resin-water-ethanol volume ratios of 9-0-1, 8-1-1, 7-2-1, 5-4-1, and 3-6-1. They were applied to smear-layer-covered dentin, followed by a bonding resin and composite build-ups for microtensile bond testing and TEM examination of tracer penetration. Increasing water concentration from 0-60 vol% improved acidic monomer ionization that was manifested as increasing hybrid layer thickness. However, significantly higher bond strength was observed in the 7-2-1 group, with minimal nanoleakage in the corresponding hybrid layer. When self-etching primers are formulated, a balance must be achieved to provide sufficient water for adequate ionization of the acidic monomers, without lowering the resin concentration too much, to optimize their bonding efficacy to dentin.

Human glutathione S-transferase P1 polymorphism and susceptibility to smoking related epithelial cancer; oral, lung, gastric, colorectal and urothelial cancer.

The A/G polymorphism at nucleotide 313 in the glutathione S-transferase P1-1 (GSTP1) gene was examined in patients with different types of smoking-related cancers (oral, lung, gastric, colorectal and urothelial cancers) and healthy control individuals. This polymorphism results in an amino acid substitution from isoleucine to valine at residue 105, which reduces catalytic activity of the enzyme. In control individuals, 23.8% of individuals had GSTP1 AG or GG genotype. This rose to 37.3% [n = 83, odds ratio = 1.93 (1.05-3.58), P = 0.035] in oral cancer patients. No increase in the frequency of the GSTP1 AG or GG genotype was obtained in lung, gastric, colorectal or urothelial cancers in this Japanese population. After grouping by smoking status, no consistent difference was observed between smoking patients and corresponding control individuals for the frequency of the GSTP1 A/G polymorphism for any cancer. However, a moderate risk (odds ratio = 2.78; 95% confidence interval 1.06-7.51) was associated with this polymorphism in the non-smoking group of oral cancer patients. The results suggest the GSTP1 polymorphism at nucleotide 313 may be associated with susceptibility to oral squamous cell carcinoma in the Japanese population.

Genetic properties for the suppression of development of putative preneoplastic glutathione S-transferase placental form-positive foci in the liver of carcinogen-resistant DRH strain rats.

The post-initiation stage of hepatocarcinogenesis was investigated in carcinogen-resistant inbred DRH rats and the parental strain, carcinogen-sensitive Donryu rats. Male rats at 5 weeks of age from both strains were treated with N-nitrosodiethylamine (200 mg/kg i.p.) followed by feeding with a diet containing 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) from 2 weeks later and were then subjected to partial hepatectomy at 1 week later. At 8 weeks after the start of treatment, the mean area occupied by glutathione S-transferase placental form (GST-P)-positive lesions was about 30% in Donryu rats but less than 4% in DRH rats despite the presence of comparable numbers of foci in the livers of both strains. These observations suggested that clonal expansion of GST-P-positive foci in DRH rat liver was significantly suppressed under these conditions. Furthermore, this genetic property was dominantly inherited in the F1 rats by crosses of DRH and carcinogen-sensitive inbred F344 rats; that is, the induction of GST-P mRNA in the livers of F344 x DRH F1 rats was dominantly suppressed after administration of 3'-Me-DAB for 8 weeks as compared with parental F344 rats under the same conditions. We compared the intrinsic properties related to growth potential of liver cells between adult DRH and Donryu rats. DRH rat liver showed retarded and/or reduced DNA synthesis after partial hepatectomy or a single i.v. injection of lead nitrate and lower activity of telomerase induced by 3'-Me-DAB administration for 1 week, as compared with the Donryu rat liver. The intrinsic properties observed in this study may be related, at least in part, to the low incidence of liver tumors induced by hepatocarcinogens in DRH rats.

Ultrasonographic study of the relation of metastatic nodes to the carotid artery.

Ultrasonographic studies of the neck were performed in four patients with metastatic lymph nodes that exhibited limited mobility or fixation to the surrounding tissues on palpation to obtain information about the relationship of nodes to the carotid artery. Comparison of the ultrasonograms with the operative findings disclosed that when a metastatic lymph node adhered to the carotid artery, the lymph node pulsated with flattening of the carotid artery and the echoes between the metastatic lymph node and carotid artery were attenuated.

Optimizing filler content in an adhesive system containing pre-reacted glass-ionomer fillers.

OBJECTIVES: (1) To evaluate the optimal concentration of the calcium type pre-reacted glass-ionomer (PRG-Ca) fillers in experimental light-activated adhesives for bonding to tooth substrates and fluoride release; (2) to evaluate the polymerization reactivity of these experimental filled adhesives; and (3) to examine the ultrastructure of the resin-dentin interface bonded with the commercial version of this self-etching adhesive (Imperva Fluoro Bond, Shofu Inc., Kyoto, Japan). MATERIALS AND METHODS: PRG-Ca fillers were prepared from the acid-base reaction of calcium type fluoroaluminosilicate glass with poly(acrylic acid) in water. Different experimental light-cured adhesives were prepared, with 0-57wt% PRG-Ca fillers and 3wt% aerosil silica incorporated in a resin matrix. Twenty-four hours shear bond strengths to bovine enamel and dentin were assessed using the adhesive with/or without accelerated aging. The cumulative amount of fluoride released from the cured adhesives and differential scanning calorimetry (DSC) measurements were also conducted. 180-grit SiC paper polished human dentin disks were treated with Imperva Fluoro Bond that contains 17wt% PRG-Ca fillers and prepared for TEM examination. RESULTS: Increase in PRG-Ca filler content of experimental adhesives was highly correlated with the decrease in bond strengths to dentin (r=-0.96 to -0.99), the increase in cumulative fluoride release, (r=0.97) and the decrease in polymerization energy (cal/g) of the adhesives (r=-0.99) (p<0.001). A PRG-Ca content of 17wt% provided optimal bond strength to enamel and dentin after accelerated aging and fluoride release. TEM showed that salt-like matrices were present around the hydrogels and remnant glass cores of the PRG-Ca fillers. The commercial self-etching primer completely dissolved the smear layer and formed 2 micrometer thick hybrid layers in intact dentin. SIGNIFICANCE: The use of silanized PRG-Ca fillers provides good adhesion and a source of fluoride release in a commercially available self-etching adhesive system.

A case of cystic lymphangioma extending from the neck to the tongue. Management of the lesion remaining after surgery.

A case of cystic lymphangioma in a child is reported. The lesion extended bilaterally from the neck to the tongue. Complete removal of the tumour in the floor of the mouth and the tongue was impossible. Later, swelling in these regions caused dyspnoea. The residual lesion was treated by external irradiation (60 Co total dose of 30 Gy). During a three-year follow-up period, no recurrence of the swelling, respiratory distress, or side-effects of radiation were observed.

Fas antigen expression and outcome of oral squamous cell carcinoma.

Paraffin sections of biopsy specimens obtained from 46 patients with oral squamous cell carcinomas were stained with both anti-peptide antibody against human Fas antigen and monoclonal mouse antibody against human proliferating cell nuclear antigen (PCNA). The patients received chemotherapy with a combination of carboplatin and peplomycin sulfate or mitomycin C and peplomycin sulfate before surgery. The relation between the expression of Fas antigen and the clinical features of each case was examined. The correlation between PCNA and Fas antigen expression was also studied. The mean PCNA labeling index of the 22 Fas-negative cases was 46.9%, which was significantly higher than that of the 24 Fas-positive cases (39.5%). Strong correlations were found between the expression of Fas antigen and the response to chemotherapy, tumor recurrence, and survival. The Fas-negative group had only a minor response to chemotherapy and a poor outcome, whereas the Fas-positive group had a better response to chemotherapy and a good outcome. Although lymph node metastasis was significantly related to survival, there was no correlation between Fas antigen expression and lymph node metastasis. The Kaplan-Meier survival curve of patients positive for Fas antigen was significantly better than that of patients negative for Fas antigen. Our results suggest that Fas antigen expression is an independent predictor of outcome whose usefulness should be evaluated in prospective studies.

Effect of 4-acryloxyethyltrimellitic acid in a self-etching primer on bonding to ground dentin.

To develop a self-etching primer for ground dentin, 4-acryloxyethyltrimellitic acid (4-AET) was newly synthesized, and the effect of concentrations varying from 0 (control) to 56.5 wt% 4-AET in the water/ HEMA primer on bonding to the dentin was investigated. Bond strength to the dentin was significantly affected by the inclusion of 4-AET in the primer which also contained N,N-di(hydroxyethyl)-p-toluidine (DEPT) when compared with the control (0% 4-AET) (p < 0.01). The optimum 4-AET-concentration and the mean bond strength (SD) were found to be 6.5 wt%: 24.2 (3.6 MPa, 37.4 wt%: 25.3 (4.4) MPa, 47.2 wt%: 26.9 (11.6) MPa and 54.4 wt%: 29.7 (12.9) MPa. The role of DEPT in the 4-AET/HEMA primer was assessed, and the optimum DEPT-concentration was found to be 0.154 and 0.307 mol%. Regarding the hypothetical bonding mechanism to dentin, it was thought that the ionized 4-AET in water/HEMA would penetrate into dentin substrates, and DEPT as an accelerator in situ would facilitate photo-polymerization at the dentin-resin interface, and result in increased bond strength to ground dentin.

Effects of aminobenzoic acid derivatives with 4-AET/HEMA in self-etching primer on bonding to ground dentin.

The effect of the inclusion of aminobenzoic acid derivatives (ABAD) in a self-etching primer comprising 4-acryloxyethyltrimellitic acid (4-AET), HEMA and water on shear bond strength to ground dentin was investigated. The mean bond strengths to dentin were significantly increased by the inclusion of 0.307 mol% ABAD in the 4-AET/HEMA primer, when compared with the control (0 wt% ABAD) (p < 0.01). A particularly high value (38.0 MPa) of shear bond strength was obtained in the use of the primer containing p-nitroanthranilic acid (p-NAA). It seemed to assume that the effect of p-NAA could be caused by the strong electron-withdrawing group of -NO2. From SEM observation, it was found that bonding resin appeared to adhere strongly to the ground dentin without formation of any resin-tags in the dentinal tubules. It was thought that the ABAD with 4-AET/HEMA could perform facilitating photo-polymerization at the bonding interface, and resulted in increased bond strength to ground dentin, and that the bond strength could be affected by the electronegativities of substitutional groups of ABAD.

Effects of radical polymerizable spirocyclic monomers with new polymerization initiator systems on adhesion.

To develop a non-polymerization shrinkage adhesive resin, the effects of the contents varying 0-20 wt% radical polymerizable spirocyclic monomers of 2-methylene-1, 4, 6-trioxyaspiro [4, 6] undecane (MTSU) and 2-methylene-8, 9-benzo-1, 4, 6 trioxyaspiro [4, 4] nonane (BTSN) together with three kinds of initiator systems in adhesive resin on bonding to both Ni-Cr alloy and unetched enamel were investigated. Tensile bond strength to either Ni-Cr alloy or unetched enamel was affected by the inclusion of MTSU or BTSN, and indicated that increased contents of MTSU or BTSN resulted in decreased bond strength to the metal in the negative correlations. Regarding the bond strength to Ni-Cr alloy, however, the effective concentration of BTSN was found to be 5 wt%, and the mean bond strength was 58.5 and 58.6 MPa, respectively. The data of differential scanning calorimeter measurement, on the other hand, showed that the copolymerization of MTSU with conventional methacrylate monomers was not completely achieved.

Use of lyophilized porcine skin to the oral wound. Clinical application and experimental evaluation as a temporary dressing material.

In order to cover the defect of the oral mucosa temporarily, we used lyophilized porcine skin (LPS) in 10 cases. The use of LPS seemed to be effective from the following points of view; alleviation of postoperative pain and as a protection against exogenous irritants. A fixation method, that is, a continuous locked suture, was devised technically to prevent the LPS from tearing by suturing. With this simple method, the patient maintained good oral hygiene and had only a slight discomfort. Histological examination using Japanese white rabbits showed no apparent difference in wound healing between this method and interrupted suture with tie-over compression. Re-epithelialization of the wound in the non-dressed (control) group was recognized earlier than that in the LPS-covered group.

Histologic evaluation of tumor persistence at the surgical margins in oral cancer: an evaluation of all surgical margins using paraffin-embedded sections and its usefulness and limitations.

An evaluation of frozen sections at all surgical margins (Mohs' surgery) was attempted in three patients, in order to determine whether or not a tumor persisted at the surgical margins following surgery for carcinoma of the oral cavity. However, sectioning from the fresh tissue was difficult, and moreover, duration of the surgery was lengthened. It thus seems that this method is not suitable for a routine evaluation of the surgical margins. Based on this, surgical specimens after formalin fixation were evaluated in eight patients. The use of paraffin-embedded sections compensates the disadvantages in using frozen sections. On the other hand, when a residual tumor is detected, any additional excision should be delayed. In two patients, who were evaluated using paraffin-embedded sections, a persistent tumor was detected. In another patient a recurrent tumor developed, despite having completely tumor-free margins. In this patient, the growth of the tumor appeared to be discontinuous. When skip lesions are histologically suggested, adjuvant therapy including radiotherapy should be considered, even when a persistent tumor is not evident. A reliable evaluation of all surgical margins is difficult in either a T4 tumor or in a malignant tumor of the gingiva and hard palate. Microscopic evaluation of all surgical margins using paraffin-embedded sections is considered to be practical in helping to elucidate the microscopic extent of a tumor, although there are several limitations in its application.

Repair of a cleft palate in a child with hemophilia A.

The repair of a cleft palate in a child with severe hemophilia A was performed under replacement of factor VIII. The plasma level, over 50% of the normal value, was maintained during surgery. The estimated blood loss during surgery was 15 ml. In order to control postoperative bleeding, it is recommended that the factor VIII level be maintained above 30% for two weeks.

[A case of erythroplakia of the palate, tongue and gingiva].

A case of a 58-year-old man with erythroplakia, which occurred in the palate, tongue and gingiva, is reported. The histological diagnosis of a biopsy specimen was carcinoma in situ. The patient was treated with irradiation (60Co, 5060 cGy) and chemotherapy (5-FU, arterial infusion, 6400 mg). The erythema completely disappeared following a 6-week therapy, and no atypical cells were histologically recognized. There were no signs suggesting recurrence or metastasis during the follow-up period of 5 months.

Cysts of the oral mucosa in newborns: a clinical observation.

Nodules or cysts of the oral mucosa occurred with an incidence of 88.7 per cent in 541 Japanese newborn infants. No infant was over 8 days old. This incidence is higher than that reported in Caucasian and Negro newborns. It may be suggested that the frequency of visible nodules have a close relation to growth and development in the fetal life, because the cysts seen in newborns can be recognized histologically in most fetuses, as demonstrated in other papers. Although a variety of terminology for these nodules have been used, these oral cysts can be classified as follows: gingival cyst in the newborn (dental lamina cyst) and median palatal mucosal cyst (Epstein's pearl).

[Interference in endotoxin and fungal polysaccharide assays from blood products and antimicrobial agents].

A conventional chromogenic limulus test (CCLT, normal plasma value: less than 10 pg/ml) detects both of endotoxin and beta-1,3-glucan, while a chromogenic endotoxin-specific test (EST: less than 3 pg/ml) detects only endotoxin. Two sources of pseudo-positive result in CCLT and/or EST were studied; (1) factor G-activating material found in blood products, which is indicative of fungal infections, and (2) interaction in diazo-coupling process of the tests by antibiotics or sulfonamides. CCLT and EST values obtained from 13 vials of blood products including human albumin, antithrombin III, and antihemophilic globulin were 284.6 +/- 284.6 pg/ml and 20.2 +/- 26.4 pg/ml (mean +/- SD), respectively. High CCLT values accompanied by low EST values indicate factor G-activating material in the blood products rather than endotoxin. Sample blanks of 42 plasma specimens obtained from 19 patients were 23.7 +/- 34.7 pg/ml by CCLT and 19.2 +/- 31.5 pg/ml by EST. All the patients were administered Sulfamethoxazole/Trimethoprim (SMX/TMP), Aztreonam (AZT), Ceftazidime (CAZ), Imipenem/Cilastatin (IPM/CS), or Silver sulfadiazine. SMX/TMP, AZT, CAZ, IPM/CS, and Cefmenoxime were demonstrated to react with the diazo-coupling reagents used in CCLT and EST, and to cause false-positive result in the tests. Thus the investigation of blood product and sample blank is required for the assay of endotoxins or fungal polysaccharides using CCLT and EST.

[The causes of abnormal coagulation system in the early phase of burns].

The relationship between abnormality in blood coagulation and Burn Index (B.I.) were examined in 174 patients treated in our department for trauma during past 7 years. Platelet counts decreased rapidly and became minimal at 3rd or 4th hospital day, but PT, APTT, fibrinogen and FDP were abnormal in many cases over 30% BSA only within 24 hours after thermal injury. The platelet counts at 3rd hospital day and PT within 24 hours were well correlated with Burn Index (platelet vs. B.I. r = 0.665, p less than 0.01; PT vs. B.I., r = 0.587, p less than 0.01). And PT was also well correlated with plasma total protein (r = 0.686, p less than 0.01). AT-III, plasminogen and alpha 2 PI had also a tendency of interrelation to plasma protein level. These data suggest that systemic intravascular coagulation does not commonly complicate immediately after thermal injury, although consumption of coagulation factors are mainly occurred at the site of burn and correlated with the loss of plasma protein.