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M Toledano

Publications and source records attributed to M Toledano.

At least 37 records · Page 2Linked to original sources
PubMed2000

Principal component analysis and cluster analysis for the characterization of dental composites.

Various experimental dental materials were characterized using chemometric methods. The main aim of the study was to ascertain which composite materials present the best properties for use in restorative dentistry. Bisphenol-alpha-glycidyl methacrylate-based composites containing hydroxyapatite as a filler and a coupling agent were prepared using a photocuring polymerization procedure. Several chemical and mechanical properties of experimental composites were measured and the corresponding data were further studied using principal component analysis and cluster analysis. Results from the characterization allowed the most appropriate materials to be selected. Various composites presented acceptable general properties suggesting their suitability as substitutes for commercial materials in dentistry.

Cluster Analysis↗
PubMed2000

Risk of mortality, cancer incidence, and stroke in a population potentially exposed to cadmium.

OBJECTIVES: To follow up mortality and cancer incidence in a cohort potentially exposed to cadmium and to perform a geographical (ecological) analysis to further assess the health effects of potential exposure to cadmium. METHODS: The English village of Shipham has very high concentrations of cadmium in the soil. A previous cohort study of residents of Shipham in 1939 showed overall mortality below that expected, but a 40% excess of mortality from stroke. This study extends the follow up of the cohort for mortality to 1997, and includes an analysis of cancer incidence from 1971 to 1992, and a geographical study of mortality and cancer incidence. Standardised mortality and incidence ratios (SMRs and SIRs) were estimated with regional reference rates. Comparisons were made with the nearby village of Hutton. RESULTS: All cause cohort mortality was lower than expected in both villages, although there was excess cancer incidence in both Shipham (SIR 167, 95% confidence interval (95% CI) 106 to 250) and Hutton (SIR 167, 95% CI 105 to 253). There was an excess of mortality from hypertension, cerebrovascular disease, and nephritis and nephrosis, of borderline significance, in Shipham (SMR 128, 95% CI 99 to 162). In the geographical study, all cause mortality in Shipham was also lower than expected (SMR 84, 95% CI 71 to 100). There was an excess in genitourinary cancers in both Shipham (SIR 160, 95% CI 107 to 239) and Hutton (SIR 153, 95% CI 122 to 192). CONCLUSION: No clear evidence of health effects from possible exposure to cadmium in Shipham was found despite the extremely high concentrations of cadmium in the soil.

Cadmium Poisoning↗
PubMed1999

Effect of acid etching and collagen removal on dentin wettability and roughness.

It was recently reported that removal of the collagen network from etched dentin does not affect dentin bond strengths. The aim of this study was to determine if the removal of the collagen fibers results in changes in dentin roughness and wettability. Twenty cary-free extracted human third molars were sectioned parallel to the occlusal surface to expose either superficial or deep dentin. Dentin was ground flat through 600-grit SiC abrasive paper under water to provide uniform surfaces. Observed contact angle measurements were performed to assess wettability by using the axisymmetric drop shape analysis technique using water and a water-based primer. Average roughness was determined with a profilometer. The specimens were analyzed just after being ground, after etching with 35% H(3)PO(4) gel for 15 s, and after etching and deproteinization with 5% NaOCl for 2 min. Data were analyzed with two-way ANOVA and Newman-Keuls multiple comparison t test procedure. Etching resulted in an increase in surface roughness and dentin wettability. For deep dentin, collagen removal did not influence the average roughness, but it resulted in a significantly greater degree of wettability. The degree of wettability for deep dentin was greater than for superficial dentin.

Acid Etching, Dental↗
PubMed1999

Laparoscopic treatment vs open surgery in the solution of major incisional and abdominal wall hernias with mesh.

BACKGROUND: Despite being one of the most exact indications, laparoscopic treatment of eventrations and ventral hernias is barely known among the array of laparoscopic techniques. METHODS: A total of 60 patients were assigned at random over a 3-year period to two homogeneous groups to be operated on for major ventral hernias with mesh. Half of them were operated upon laparoscopically and the rest with open surgery. Early and longer-term complications were analyzed, as were operative time and postoperative hospital stays. RESULTS: The two groups were homogeneous in terms of demographic and clinical characteristics. The group that was operated on laparoscopically presented a lower rate of postoperative and longer-term complications; similarly, surgery time was significantly lower (p < 0.05). Hospitalization time was also significantly lower than in the group undergoing conventional open surgery (p < 0.05). CONCLUSIONS: Laparoscopic treatment of postoperative eventration and primary ventral hernia reduces complications and relapse rates, eliminates reintervention through mesh infection, reduces operative time, and considerably shortens the hospital stay.

Female↗
PubMed1999

Microleakage of Class V resin-modified glass ionomer and compomer restorations.

STATEMENT OF PROBLEM: Resin-modified glass ionomers and polyacid-modified resin composites (compomers) have been introduced to provide esthetic restorations. However, there is concern about the marginal sealing ability of these materials, especially at the dentin (cementum) aspects of restorations. PURPOSE: This in vitro study evaluated the microleakage of Class V restorations made with resin-modified glass ionomers or a compomer. MATERIAL AND METHODS: Thirty noncarious human molar teeth were used. Standardized kidney-shaped Class V cavity preparations were placed in the buccal and lingual surfaces at the cementoenamel junction. Teeth were randomly assigned to 3 experimental groups of 10 teeth each and restored as follows: group 1, Fuji II LC; group 2, Vitremer; and group 3, Dyract. In all cases, the manufacturers' instructions were strictly followed. All materials were placed in a single increment. Unfinished restorations were immediately coated with the respective manufacturers' sealer or varnish and this was either light cured for 20 seconds or allowed to air-dry. After 24 hours, teeth were finished to contour and to the cavosurface margins, coated with nail varnish except for 1 mm around the restoration margin, thermocycled (1000x, 5-55 degrees C) and placed in a solution of 2% basic fuchsin dye for 24 hours at room temperature. The staining along the tooth restoration interface was recorded. RESULTS: Kruskal-Wallis 1-way analysis of variance revealed significant differences among all restorative materials for the overall, occlusal, and gingival scores (P =.03, P =.01, P =.01, respectively). Occlusal and gingival scores for each matched pair of restorative materials using the Wilcoxon test showed statistically significant differences between Fuji II LC glass ionomer cement and Dyract composite, both for the occlusal (P =.005) and gingival (P =.005) margins and also as an overall evaluation (P =.01), with Fuji II LC showing the least dye penetration. Vitremer revealed dye penetration scores not significantly different from Fuji II LC glass ionomer cement or Dyract composite. CONCLUSION: Resin-modified glass ionomers showed less or similar microleakage than the polyacid-modified composite resin tested.

Analysis of Variance↗
PubMed1999

Bracket bonding with 15- or 60-second etching and adhesive remaining on enamel after debonding.

The purposes of this study were to (1) evaluate the shear bond strength of brackets fixed to enamel that has been etched for 15 or 60 seconds, (2) correlate etch time with amount of resin remaining on the enamel after debonding; and (3) evaluate enamel morphology after acid etching. Sixty recently extracted human premolars were randomly divided into two groups. Group 1 was etched for 15 seconds, and group 2 for 60 seconds. A 37% phosphoric acid solution was used for etching. The brackets were Mini-Taurus, and the bonding system was Mono-Lok2. After bonding, the teeth were held at 37 degrees C and 100% humidity for at least 48 hours. To debond, a blade was placed at the ligature groove of the bracket. The force in Newtons required to dislodge the bracket was measured, employing a crosshead speed of 1 mm/min. Bond strength was calculated on the basis of bracket area. Immediately after removal of the bracket, the teeth were rinsed and dried using an air-water syringe, and the adhesive remnant index (ARI) was assessed. Enamel surfaces were analyzed using a scanning electron microscope (SEM). The results showed that shear bond strength was greater (p=0.016) when the enamel was etched for 60 seconds, and the amount of adhesive remaining on the teeth was also greater (p=0.001). There was no significant correlation between shear bond strength and the ARI calculated in the total sample (n=60, r=0.017; p>0.05). SEM evaluation revealed that the shorter etching time created a less retentive enamel surface. Absolute enamel loss also decreased.

Acid Etching, Dental↗
PubMed1999

Acid-etching and hydration influence on dentin roughness and wettability.

Adhesion of restorative and protective materials to dentin is an important requirement for operative and preventive dentistry. Wettability and roughness are dentin substrate conditions that are critical to establishing good adhesion. This study examined superficial and deep dentin for variations in water contact angle measurements and roughness for polished, etched, dehydrated, and rehydrated states. Superficial and deep dentin disks from 6 non-carious third molars were prepared for AFM (Atomic Force Microscope) observation, roughness measurement, and contact angle measurements following specific treatments: hydrated and polished, etched (10% H3PO4), dehydrated (desiccator for 24 hrs); and rehydrated (in water for 24 hrs). Contact angles were measured by means of the ADSA (Axisymmetric Drop Shape Analysis) technique with filtered and purified water of surface tension 72.79 ergs/cm2. The AFM was used to quantify the intertubular roughness. Mean and SD of roughness and contact angle were calculated for each dentin state, and two-way Repeated Measures ANOVA with Tukey's HSD multiple comparisons were performed at p < 0.05. Wetting and roughness both increased after etching, with roughness tending to increase further while wettability dramatically decreased after desiccation. After rehydration, water contact angle values were equivalent to those of the etched condition. Although intertubular roughness did not depend on depth, lower water contact angles were found for deep dentin. Depth and dehydration resulted in altered dentin substrates with exposed hydrophobic moieties that could interfere with bonding to hydrophilic primer coats.

Acid Etching, Dental↗
PubMed1999

An ultra-morphological characterization of collagen-depleted etched dentin.

PURPOSE: To evaluate the ultramorphology of superficial and deep dentin after etching with 35% phosphoric acid (H3PO4) and after etching with 35% H3PO4 followed by deproteinization with 5% sodium hypochlorite (NaOCl). MATERIALS AND METHODS: Two dentin disks (superficial and deep dentin) were obtained from each of 10 extracted human third molars by slow-speed sectioning. Dentin was polished with wet 600-grit SiC abrasive paper for 1 min to provide smooth surfaces. The occlusal surface of each disk was etched with 35% H3PO4 for 15 s and thoroughly rinsed. The specimens were kept moist and analyzed using Atomic Force Microscopy (AFM). Half of the specimens were deproteinized by rubbing with 5% NaOCl for 2 min, followed by a 30 s rinse with deionized water. After AFM analysis of the deproteinized specimens, all disks were fixed in a solution of glutaraldehyde and paraformaldehyde, dehydrated in ethanol and dried in hexamethyldisilazane. The dentin disks were then mounted on aluminum stubs for field-emission scanning electron microscope (FESEM) observation. RESULTS: The surface of etched dentin displayed a granular layer of silica, which did not reach the peritubular collagen area. The silica was more uniformly distributed in superficial dentin than in deep dentin. In spite of the silica deposition, the intertubular porosity remained unobstructed when observed at high magnification. Under a lateral view, intertubular dentin was demineralized to a depth of 2.0 to 2.5 microns for superficial dentin, and 2.5 to 3.0 microns for deep dentin. Deproteinization with 5% NaOCl removed the exposed collagen both for superficial and deep dentin. The number of open tubules was greater for deep dentin. Deproteinization of superficial dentin revealed an extensive labyrinth of lateral secondary tubules and anastomoses, which opened on the intertubular region and on the peritubular area close to the surface. This phenomenon decreased the area of exposed intertubular dentin as compared to etched specimens. In deproteinized deep dentin, the lateral anastomotic tubules were not consistently observed on the intertubular area, but were easily depicted on the peritubular area.

Acid Etching, Dental↗
PubMed1998

Monitoring of evoked potentials during spinal cord ischaemia: experimental evaluation in a rabbit model.

OBJECTIVES: Somatosensory evoked potentials (SEPs), spinal evoked potentials (Spinal-EPs), and motor-evoked potentials (MEPs) were monitored in a rabbit model of spinal cord ischaemia to evaluate their accuracy and relationship to clinical status. METHODS: A modified rabbit spinal cord ischaemia model of infrarenal aortic occlusion for 21 min was employed (30 rabbits). After baseline SEPs, Spinal-EPs, and MEPs were obtained, evoked potentials were recorded continuously during and after clamping of the aorta (30 min). Neurological outcome at 24 h was correlated with evoked potentials, and histopathological findings. RESULTS: Fifteen animals became paraplegic. MEPs were always abolished after clamping of the aorta while Spinal-EPs and SEPs remained. The sensory evoked potentials (SEPs and Spinal-EPs) were the least sensitive to spinal cord ischaemia, and their presence had no correlation with the final clinical status (50% of false negatives). This was consistent with histopathological examination that showed damage almost entirely confined to the anterior horn, while the dorsal columns were generally well preserved. High spine MEPs evoked by twitch stimulation was the best predictor of clinical outcome (0% of false negatives, 0% of false positives). CONCLUSIONS: SEPs and Spinal-EPs cannot be used as safe monitors of ischaemia of the spinal cord. High spine MEPs evoked by twitch stimulation was the most useful for real-time evaluation of spinal cord ischaemia, and the best predictor of neurologic outcome during reperfusion.

Animals↗
PubMed1998

Interaction between iron metabolism and 2,3,7,8-tetrachlorodibenzo-p-dioxin in mice with variants of the Ahr gene: a hepatic oxidative mechanism.

The binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) with the aryl hydrocarbon (AH) receptor and subsequent changes in gene expression have been studied intensively, but the mechanisms by which these lead to toxicity are unclear. We investigated the influence of iron, previously implicated in TCDD-induced hepatic porphyria, in mice with alleles of Ahr that encode receptors with varied affinity for TCDD. The administration of iron to Ahrb-1 C57BL/6J (AH-responsive) mice before a single dose of TCDD (75 micrograms/kg) markedly potentiated not only the hepatic porphyria but also general hepatocellular damage and elevation of plasma hepatic enzymes. The formation of hydroxylated and peroxylated derivatives of uroporphyrins formed from uroporphyrinogen and the induction of a mu-glutathione transferase (GST) were consistent with the operation of an oxidative mechanism. In a comparison of C57BL/6J mice with Ahrb-2 BALB/c (AH-responsive) and Ahrd SWR and DBA/2 (AH-nonresponsive) mice, iron overcame the weak hepatic porphyria and toxicity responses in BALB/c and SWR strains but not in DBA/2. CYP1A isoforms are strongly implicated in the mechanism of porphyria, but activities were lowered by 20-30% with iron treatment, and a comparison of levels between strains did not fully account for the resistance of DBA/2 mice. Studies with the use of gel shift assays and cytosolic aconitase of the capacity of the iron regulatory protein controlling the translation of some iron metabolism proteins showed a significant difference between C57BL/6J and DBA/2 mice after the administration of TCDD. We conclude that iron potentiates both the hepatic porphyria and toxicity of TCDD in susceptible mice in an oxidative process with disturbance of iron regulatory protein capacity. Iron even overcomes the AH-nonresponsive Ahrd allele in the SWR strain but not in DBA/2 mice, which remain resistant.

Alleles↗
PubMed1998

[Microsurgical approach and graft anastomosis to the trunk of the facial nerve in the Wistar rat].

An experimental model was developed for the purpose of investigating neural regeneration of the facial nerve in Wistar rats. The anatomic references used to locate the facial nerve at its exit from the skull base are described. A detailed description of the microsurgical anastomosis of cryopreserved nerve allografts is given. The major advantages and disadvantages of rat models compared with other animal models for experimental studies of the facial nerve are discussed.

Anastomosis, Surgical↗
PubMed1996

Influence of enamel prophylaxis on wettability of three commercially available orthophosphoric acids.

An in vitro study was performed to assess the wettability of orthophosphoric acid after different procedures for cleaning the enamel surface. Ninety noncarious third molars were randomly distributed into three groups with different enamel surface treatments: an air-powder polisher unit, prophylaxis pastes, and no enamel surface cleaning. Three commercially available orthophosphoric acids were used, and there were 10 teeth in each group. Acid viscosity values and contact-angle measurements were obtained. Each enamel surface was also examined with the scanning electron microscope. Results suggested that the surface treatment with which the best spreading of the acid solution was attained was the air-powder polisher. The least spreading of the acid was obtained with prophylaxis pastes, in which contact angles were even higher than those obtained on the untreated enamel surface. The 3M acid solution was the one that showed the best spreading onto the enamel surface.

Acid Etching, Dental↗
PubMed1996

An in vitro comparison of micro leakage in three glass ionomer cements used as retrograde filling materials.

The aim of this study was to evaluate the sealing ability of conventional self-cured glass ionomer cement, silver glass ionomer cement and light-cured glass ionomer cement as retrofilling materials. Micro-leakage was assessed by introducing the samples into a 1 per cent solution of methylene blue for eight days at a constant temperature of 37 degrees C. Dye penetration was greater when silver glass ionomer cement was used in comparison to the other two materials tested; the difference was statistically significant. Conversely, the sealing ability of light-cured glass ionomer cement was significantly higher than that of conventional glass ionomer cement. The condition of the dentine-filling material interface and the marginal adaptation of the glass ionomer cements under study were assessed using scanning electron microscopy.

Cermet Cements↗
PubMed1995

Short-term changes in lymphocytes after placement of silver amalgam restorations in healthy subjects.

OBJECTIVES: The purpose of this study was to evaluate the changes in lymphocyte subpopulations that have led to immune system alterations after amalgam restorations were placed. METHODS: A controlled, quasi-experimental pretest-posttest design was used to investigate the immune effects of silver amalgam restorations in a sample of 60 individuals (30 experimental and 30 control subjects) aged 18 to 21 y. Two blood samples were obtained 15 d apart from each participant. In each experimental subject, two amalgam restorations were placed in posterior teeth immediately after the first blood sample was collected. The changes in lymphocyte subpopulations in the two groups were compared by multivariate analysis. RESULTS: There was a greater change in T8 lymphocytes in experimental than in control subjects; increases in B, DR, NK, and CD45R lymphocytes were smaller in experimental than in control subjects; the changes in T3 and T4 lymphocytes did not differ significantly between the two groups. SIGNIFICANCE: Despite the statistical significance of some differences between the two groups, the differences are not considered to be clinically relevant for the 2 wk time period after placement.

B-Lymphocytes↗
PubMed1995

[Gastrointestinal hemorrhage secondary to heterotopic jejunal pancreas].

A case of heterotopic pancreas located in the small intestine is herewith presented. The 19-years male patient had been admitted three times since 1991 for an anemic syndrome secondary to melena. The origin of the hemorrhage was not determined with the studies performed (intestinal transit, opaque enema, esophagogastroscopy, colonoscopy and gammagraphy with technetium 99). On the last admission a vascular lesion low flow was observed on arteriography of the upper mesenteric artery on the mesenteric edge of the proximal jejunum. Following laparotomy a small tumor was found in the jejunum and 5 cm of the intestine including the tumor was resected. The anatomic pathologic results demonstrated a heterotopic pancreas.

Adult↗
PubMed1995

Environmental microbial contamination. Pilot study in a dental surgery.

Environmental contamination by bacterial aerosols occurs every day in the dental surgery. The aim of this study was to determine bacterial levels in five different areas of a dental surgery during ultrasonic scaling procedures using bacterial cultures. Two areas with markedly different amounts of infective aerosols were identified. The role of the air conditioning system was also assessed. There was evidence that the air conditioning system could act as a vehicle for the transmission of microorganisms.

Aerosols↗
PubMed1991

HIV-associated non-Hodgkin's lymphomas: clinical characteristics and outcome. The experience of the French Registry of HIV-associated tumors.

From 1/87 to 12/89, the French Registry of HIV-associated tumors recorded 131 cases of intermediate- and high-grade non-Hodgkin's lymphomas (NHL). There were 47 small non-cleaved Burkitt-type lymphomas (SNCL), 32 immunoblastic lymphomas (IL) and 52 diffuse large-cell or predominantly large-cell lymphomas (LCL). There were differences in the clinical patterns of the histological subtypes. Isolated extranodal presentation was less frequent in SNCL (2/47) than in IL (13/32) and LCL (17/49) (p less than 0.0001). In the latter two groups, the central nervous system was the principal site of extranodal involvement (16/30), 87% of SNCL, patients had no previous manifestations of AIDS whereas 40% of IL and LCL patients presented full-blown AIDS (p less than 0.01). At the time of NHL diagnosis, the median blood CD4 lymphocyte count was higher in SNCL (266/microL) than in LCL (125/microL, p less than 0.05) and IL (80/microL, p less than 0.01), 69% of stages I/II patients, 31% of stages III/IV, and 33% of stage ie patients achieved complete remission (CR), p less than 0.05. Overall median survival time was 5 months. There was no statistical difference in CR and survival rates among histological types. The two-year actuarial survival rate was 25% (median 8 months) for initially asymptomatic patients or those with persistent generalized lymphadenopathy (PGL) and 9% (median 3 months) for those previously with AIDS-related complex (ARC) and AIDS patients (p less than 0.001). Response to treatment was the other predictor factor. The two-year survival rate was 42% (median 16 months) for patients who achieved CR, and 5% (median 3 months) for those who did not.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗