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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this in vitro study, the effect of application techniques on marginal adaptation of thermal cycled class V restorations restored with an actual dentinal adhesive were quantitated using SEM and dye penetration. Under optimal application conditions, excellent results were generated: though a simple bulk insertion technique was used, no difference was found between enamel and dentin margins before and after thermal loading. On the other hand, contamination of the bonding agent with saliva before composite resin insertion dramatically decreased the percentage of "excellent margin" in dentin and in enamel. Similar effects were found after protecting the bonding agent with an insulating gel. No improvement in marginal adaptation was found after reapplication of the bonding agent. The class V inlay did not show better results than the direct filling technique. However, postcured inlays performed better than their non-postcured counterparts. Without etching enamel with a phosphoric acid gel, but by priming its surface, approximately 80% of "excellent margin" were found in enamel before thermal cycling. This percentage decreased significantly after thermal loading. Restorations totally confined to dentin had slightly lower percentages of "excellent margin" than the mixed class V fillings. The results of this study indicated, that by using dentinal adhesives, little changes and deviations from the correct procedure result in significant alterations in marginal adaptation.
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PMID:[The effects of the processing technic on dentinal adhesion]. 152 19

A new functional bonding agent was tested in the placement of mixed class V in vitro restorations. Variable insertion procedures of the composite material were also evaluated. One of the procedures was the direct filling technique, the other were direct immediate composite inlays, cemented with light, chemically or dual cured composite cements. The quantitative SEM marginal analysis results showed a significant superiority (p less than 0.05) of the adhesive inlay restorative procedure over the direct filling technique. Dye penetration confirmed these findings. Among the inlay groups, postcuring and the curing method of the composite cement were crucial for the success.
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PMID:[The optimization of dentin bonding in mixed Class-V cavities]. 173 28

Esthetic restorations for class V lesions extending into root dentin often show marginal discoloration after some time. In this clinical study the long term quality of glass ionomer cement and "sandwich" restorations was compared with each other. In 19 patients 83 class V lesions with the apical margin in dentin were restored with glassionomer cement (I: Fuji II/G-C Dental; II: Ketac Fil/ESPE) or with a glass ionomer liner (III: Lining Cement/G-C Dental; IV: Ketac Bond/ESPE) and laminated with a composite. Where necessary the margins were prepared apically with a butt joint. The observation period between placement and last follow-up check varied between 18 and 44 months. Modified Ryge criteria were used for the clinical assessment of 77 restorations. Marginal quality was assessed in the SEM using replicas. 15.8% of the "sandwich" type and 5% of the glass ionomer cement restorations were lost. All restored teeth remained vital. Clinically the best marginal quality was found with a glass ionomer cement (II) whereas only two thirds of the sandwich restorations and the other glassionomer cement (I) had perfect margins. In the SEM the glassionomer cements had significantly less marginal openings than one of the sandwich restorations (III).
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PMID:[Glass ionomer cement and "sandwich" restorations after two years of clinical service]. 181 14

In 34 extracted molars with class V cavities (coronal margin in the enamel, apical margin in the dentin) a shoulder or a shoulder with bevel were prepared on the apical aspect. The dentin was covered with glass ionomer cement (GIC) and after beveling the neighboring enamel composite material was applied on top with enamel etching. 24 other cavities filled with either composite or glass ionomer cement served as controls. The specimen were exposed to 2000 alternating thermal tests (1 min. at 8 degrees C, 1 min at 60 degrees C) and alternations of the filling margins were recorded quantitatively using replicas in the SEM. After the alternating thermal tests GIC controls showed statistically significant better margin in enamel and dentin with shoulder preparations alone than the combined or pure composite fillings. Combined fillings with beveled apical cavity margins were superior to shoulder preparations alone. Glass ionomer cement seems to be better for the treatment of class V cavities in terms of margin tightness than composite alone or in combination.
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PMID:[Marginal gaps of combined composite and glass ionomer cement fillings in different preparations in vitro]. 263 Feb 63

The use of glass-ionomer cement in restorative dentistry has seen a revival because of its capacity for being etched and bonded to composite resin. Past investigators compared an etched cement surface with an unetched surface that was set against a smooth surface. Clinically, however, a glassy smooth surface is not produced when the cement is used as a base. Using Scotchbond bonding resin, we developed this two-part study to evaluate the tensile bond strengths of P-30TM composite resin to several glass-ionomer cements that were (a) unetched but allowed to set in air and (b) etched for 30 s with orthophosphoric acid, and to compare them with the cohesive strength of the respective cement. Using a silver nitrate staining technique, we also evaluated the microleakage of class V cavities restored with SiluxTM composite resin under a base of etched or unetched Ketac Bond cement. Although there were significant differences among three cements between their cohesive strength and the resin bond strength after the two surface treatments (p less than 0.01), the bond to the unetched surface was generally similar to that of the etched surface of the cement. The remaining groups showed no statistical difference. The microleakage was similar in the two groups. SEM micrographs showed a rough topography of the unetched cement that resembled that of the etched surface. This in vitro study suggests that acid-etching a glass-ionomer base for resin-bonding may not be necessary for specific materials. Further clinical evaluation is recommended to validate this observation intra-orally.
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PMID:Effect of etching glass-ionomer cements on bond strength to composite resin. 268 6

Sera from 35 patients with biopsy-proven diffuse proliferative (WHO class IV) or membranous (WHO class V) lupus nephritis were analyzed for the presence and size of circulating immune complexes. Elevations of the C1q solid-phase assay (C1qSP) for immune complexes were found in sera from all patients with diffuse proliferative nephritis, with a mean +/- 1 SEM of 166.8 +/- 42.0 micrograms/AHG-equivalents/ml serum, and in 71.4% of the patients with membranous nephritis (83.1 +/- 26.7, p = 0.06). Using the WHO criteria for subclasses of membranous lupus nephritis, we also designated renal biopsies as nonproliferative (WHO classes Va and Vb) or proliferative (WHO classes IV and Vc). Employing the latter groupings, we observed significant differences between C1qSP results of patients with nonproliferative (30.3 +/- 8.8) and proliferative (172.8 +/- 36.8, p less than 0.001) lupus nephritis. These data suggest that the presence of C1q-binding material in serum is pathophysiologically related to proliferative glomerular lesions, and that levels of C1qSP binding reflect renal lesions in SLE patients. Sucrose density gradient ultracentrifugation was performed on each serum, and gradient fractions analyzed for C1qSP-binding and total IgG, using techniques to minimize losses of immune complexes. The predominant peak of C1qSP activity sedimented with the 6.6S monomeric IgG. The 6.6S C1q-binding IgG was increased only in 1 of 10 patients with membranous lupus nephritis without proliferative changes, and was elevated in 16 of 25 patients with proliferative lesions (WHO classes IV and Vc). A significant negative correlation was found between the presence of this C1q-binding material and subepithelial electron-dense deposits, suggesting that the presence of this material contributed to the absence of subepithelial immune deposits. Large-molecular-weight C1qSP-binding material was also present, mainly in sera from patients with proliferative lesions. Furthermore, highly positive correlations were found between immune deposits in interstitial blood vessels and peritubular areas, and the concentrations of C1qSP-binding IgG and rapidly sedimenting IgG in density gradient analysis. Overall, these findings are consistent with the hypotheses that circulating immune complexes contribute to the pathogenesis of glomerulonephritis and interstitial nephritis in patients with SLE, and that 6.6S C1q-binding IgG plays a role in the proliferative lesions of lupus glomerulonephritis.
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PMID:Relationship between renal pathology and the size of circulating immune complexes in patients with systemic lupus erythematosus. 310 94

Three commercial dentin bonding systems were analyzed by tensile bond testing, area analysis of fractured surfaces, and SEM analysis of the tooth-resin interfaces. Tensile bond strengths in megapascals(SD) were Tenure-Marathon V ([T-M]; 8.86[3.02]), new system with low-viscosity resin ([K-LVR-P]; 6.50[2.01]), and new system without low-viscosity resin ([K-P] = 7.28[1.75]), which were significantly greater than Scotch-bond 2-P50 ([SB-P50]; 3.96[1.02]). Gaps that ranged up to 5.6 microns (mean for the group) were observed around most of the restorations at dentin surfaces and less so at enamel surfaces, where some of the restorations remained free of gaps. The gaps near the dentin margin were significantly smaller for K-LVR-P than for SB-P50. The tensile test revealed mixed failure modes in all systems, and in the cross sections of class V restorations, the gaps were confined to the dentin-resin junction.
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PMID:Bond strength, interfacial characterization, and fracture surface analysis for a new stress-breaking bonding agent. 880 51

This study determined the shear bond strength of resin composites to primary dentin using three dentin adhesives and the presence or absence of a hybrid zone. The buccal and lingual surfaces of 40 recently extracted noncarious primary teeth were ground flat with SiC paper ending with the 600 grit. The teeth were divided at randomly into eight groups of five teeth (10 surfaces) each: 1) Unetched dentin, dry dentin, All-Bond 2/Bis-Fil P; 2) Unetched dentin, moist dentin, All-Bond 2/Bis-Fil P; 3) Dentin etched for 15 sec with 10% phosphoric acid, dry dentin, All-Bond 2/Bis-Fil P; 4) Dentin etched for 15 sec with 10% phosphoric acid, moist dentin, All-Bond 2/Bis-Fil P; 5) Dentin etched with 10% maleic acid for 15 sec, dry dentin, Scotchbond Multi-Purpose/Z100; 6) Dentin etched with 10% maleic acid for 15 sec, moist dentin, Scotchbond Multi-Purpose/Z100; 7) Dentin etched with 10 citric acid/3% ferric chloride, dry dentin, Amalgambond Plus/Z100; 8) Dentin etched with 10 citric acid/3% ferric chloride, moist dentin, Amalgambond Plus/Z100. All teeth were thermocycled 1000x (5 and 55 degrees C, 30-sec dwell time), and shear bond strength testing was conducted using an Instron (crosshead speed 0.5 mm/min). Failure sites after debonding were examined with the SEM. For each group, one additional tooth was used to prepare two class V cavities (one facial and one lingual) restored according to the specification in each group, sectioned buccolingually and examined with the SEM. The results, in MPa, were: 1) 12.55 +/- 5.97; 2) 10.41 +/- 6.16; 3) 9.94 +/- 7.26; 4) 12.25 +/- 4.70; 5) 13.02 +/- 8.01; 6) 16.51 +/- 8.62; 7) 12.51 +/- 8.95; 8) 17.93 +/- 6.44. ANOVA and Student-Newman-Keuls tests showed no statistically significant differences. SEM evaluation showed that the smear layer was removed in all groups exposing primary dentin tubules infiltrated by resin. A resin-reinforced hybrid layer was readily seen in all specimens.
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PMID:A comparison of three resin bonding agents to primary tooth dentin. 920 Jan 96

The purpose of this study was to evaluate the effects of CO2 laser on dentin of class V cavities of extracted human molar teeth using a scanning electron microscope. SEM showed a smooth area with concentric lines formed by melting with subsequent recrystallization of dentin, areas of granulation, vitrified surface, numerous cracks, and irregular areas of descamative dentin. These data indicate that CO2 laser (4 and 6 watts) produces dentin alterations and limit its clinical applications.
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PMID:Effect of CO2 laser on Class V cavities of human molar teeth under a scanning electron microscope. 920 51

This study investigated the influence of "softstart-polymerization" on the clinical performance and marginal integrity of polyacid-modified resin restorations (PMR) in class V cavities. Eighty PMR restorations were placed in 20 patients [40 Dyract (DY); 40 Hytac (HY)] with (npat = 10) and without preparation (npat = 10). Restorations were light cured for 40 s either conventionally (CP) or with a lower light intensity for the first 10 s (SSP). Each patient received four restorations (DY-CP, DY-SSP, HY-CP, HY-SSP), which were examined clinically according to modified USPHS criteria, and by quantitative SEM-analysis after 7 days (baseline), 6 months and 1 year. Statistical analysis was performed using the Mann-Whitney-U test (P < or = 0.05) and error rates method. Clinically, no restoration showed recurrent caries or crevices. After 1 year, margins of 24-47% of the HY- and 36-53% of the DY-restorations were rated "Bravo". Marginal discoloration occurred in 20-37% in HY- and in 18-21% in DY-restorations. The error rates method revealed no significant differences between materials or between polymerization modes with and without preparation. Pairwise testing showed that without preparation, the marginal adaptation to dentin was significantly worse compared to enamel for HY with both polymerization modes, for DY with SSP. With preparation, no significant differences were found. Cavity preparation may have an influence on differences in marginal quality between enamel and dentin.
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PMID:Clinical performance of polyacid-modified resin restorations using "softstart-polymerization". 1080 12


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