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Biomedical subjects

U Blunck

Publications and source records attributed to U Blunck.

8 recordsLinked to original sources
PubMed1991

[Effects of dentin bonding agents on the proximal margins of ceramic inlays].

Ceramic inlays have shown good marginal seal as long as the margins of the cavities are located in enamel. The purpose of this study was to investigate the marginal seal of ceramic inlays with the cervical margins situated in dentin and to determine the effectiveness of dentin bonding agents. Sintered ceramic inlays were adhesively luted either without dentin bonding agents or with the use of Gluma or Miragebond. After thermocycling and incubation in a colored dye the penetration depth of the dye was measured on sequential sections. The used dentin bonding agents did not improve marginal seal. The glass ionomer cement base was able to prevent further penetration in most of the cases when deep leakage occurred. Unless a tight marginal seal in dentin can be achieved, the indication for adhesively luted inlays must be limited to cavities with margins located in enamel.

Ceramics↗
PubMed1990

[Time of extraction and cavity position in in-vitro tests of dentin adhesives].

Cylindrical cavities were prepared in different tooth segments (coronal, cervical and radicular) and at different times (1 hour, 1 day, 1 week and 1 month) after extraction into face-ground dentin surfaces of extracted teeth. The cavities were filled with composite resin materials using different dentin adhesives. Before and after thermocycling (TC) the marginal adaptation was evaluated using defined criteria. The statistical evaluation did not show any significant differences (p greater than 0.01) after TC within the different groups of dentin adhesives. For in vitro tests of dentin adhesives neither the position nor the time of extraction decisively influences the process.

Composite Resins↗
PubMed1989

[Comparison of two cavity preparations to examine the efficacy of dentin adhesives].

Cylindrical cavities and class V cavities were treated with six different dentin adhesives before filling them with composites. Cavity margins were studied quantitatively with defined criteria before and after alternating thermal stress tests in a scanning electron microscope. In both cavity preparations groups of dentin adhesives with significantly different efficacies (p 0.05) were identified. The efficacy of dentin adhesives and their effect on marginal adaptation of composite materials in dentin can be determined rather easily in cylindrical cavities.

Composite Resins↗
PubMed1989

Quantitative margin analysis in the scanning electron microscope.

Interface between restorative materials and tooth hard substances must be morphologically as perfect as possible to avoid plaque accumulation and subsequent secondary caries or pulpal diseases. Therefore the marginal behavior of restorations is an important parameter to predict their longevity. Morphologically, the quality of margins is characterized by different well defined criteria. Using a replica technique it is possible to assess the complete marginal circumference of restorations in the SEM. Margins of restorations show a large variety of their morphology. This publication describes a method to quantify the quality of dental restorations. The restoration margins are traced on the SEM screen with a digitizer and an interface to measure the margin's length. Simultaneously the margin quality is assessed and assigned to the corresponding lengths. The % distribution of the quality criteria for each restoration is then calculated. Using a comparative light microscope, the replicas are aligned and mounted identically in the SEM for longitudinal studies. The results presented are limited to tests for the accuracy of the method. Using 5 criteria to characterize the margin quality, it was found that the difference between two measurements by the same operator, 4 weeks apart was 3% +/- 2.6%. The largest difference for one group was 9%. In another accuracy test where 4 criteria for margin characterization were used, the difference between two measurements was 1.9% +/- 0.9%. The largest difference between two groups found was 3.4%. This method can be used for longitudinal studies in vivo, but also for in vitro screening tests with new materials.

Dental Restoration, Permanent↗