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Biomedical subjects

E Stender

Publications and source records attributed to E Stender.

At least 19 recordsLinked to original sources
PubMed2004

Comparison of the efficacy of chemomechanical caries removal (Carisolv) with that of conventional excavation in reducing the cariogenic flora.

OBJECTIVES: The usage of minimally invasive procedures and attention to patient comfort are of great importance, especially for dental treatment in small children. This has led to the development of chemomechanical methods for caries removal. The aim of this study was to compare the efficacy of chemomechanical caries removal with that of conventional excavation in reducing the count of the cariogenic flora. DESIGN AND SETTING: Subjects for this study were chosen from children admitted to dental clinic for restorative procedures under general anaesthesia. SAMPLES AND METHODS: Twenty-one children (mean age 43.5 +/- 12.0 months) with early childhood caries were included in this study. Two primary teeth with comparable degrees of carious destruction were chosen in each child (n = 42) for caries removal with Carisolv' or by means of rotary instruments. Samples from carious dentine were taken with a sterile scraping instrument, then all softened dentine was removed and a second sample was taken. All samples (n = 84) were serially diluted and plated on two different nutrient agar plates. RESULTS: After 24 h of incubation, colony forming units were determined for total bacterial counts and lactobacilli. Twelve per cent of the samples from carious dentine contained more than 10(6) bacteria, 23.8% contained more than 10(5) lactobacilli. Both methods of caries removal produced a statistically significant reduction in the bacterial counts (P = 0.0001). In at least 90.5% of the samples taken after the removal, the total bacterial count was below 10(2), and in 95.2% lactobacilli fell below 10(2). CONCLUSION: These results indicate that the efficacy of chemomechanical removal of carious dentine in children by means of Carisolv' is comparable to the results obtained by conventional methods, and thus might serve as a suitable alternative.

Bacteria↗
PubMed2001

Effect of diode laser irradiation on the attachment rate of periodontal ligament cells: an in vitro study.

BACKGROUND: The present study is part of a basic research program investigating the cellular effects of an 810 nm GaAlAs-diode laser on human periodontal tissues. The aim of the investigation was to evaluate the effects of laser treatment of root surface specimens on the attachment of periodontal ligament (PDL) cells in vitro. METHODS: Root specimens were prepared from periodontally diseased teeth. PDL cells were obtained from human third molar ligaments. Cells were cultured under simple, standardized, and reproducible experimental conditions. One hundred fifty root specimens were scaled and root planed with curets followed by air-powder abrasive treatment; 75 were then lased and 75 served as controls. The irradiation time was 20 seconds at a power output of 1 W. The root segments were placed into culture dishes, covered with a solution of PDL cells, and incubated for 72 hours. The specimens were then washed with phosphate buffer to remove cells not attached to the surface, and the adherent cells were stained with methylene blue. Cells were counted using a reflected light microscope and the cell density per mm2 was calculated. RESULTS: The analysis of 150 specimens revealed no significant differences between the groups (P = 0.347, Wilcoxon test). The cell numbers, however, were slightly higher on laser specimens. The mean was 66 cells/mm2 in the laser group and 63.7 cells/mm2 in the control group. CONCLUSIONS: The application of the diode laser at the parameters used did not have a substantially positive effect on the new attachment of PDL cells on the tooth specimens. It remains to be investigated whether the difference detected is really clinically relevant.

Aluminum↗
PubMed2000

In vitro colonisation of acrylic resin denture base materials by Streptococcus oralis and Actinomyces viscosus.

AIM: The aim of the study was to compare the attachment of two typical strains of oral bacteria to four denture base materials. DESIGN: In vitro study. METHOD: Discs of acrylic resin denture base materials (Paladon 65, polished and unpolished; Palapress; Microbase, polished and unpolished, and Triad VLC) were placed into Petri dishes with Schaedler's medium, inoculated with Streptococcus oralis 34 or Actinomyces viscosus T14V. MAIN OUTCOME MEASURES: After 24 h or 48 h the numbers of adhering bacteria were measured. RESULTS: The bacteria adhered to all discs in similar numbers: 3-9 x 10(6)/ml (viable cell count) and 9-22 x 10(8)/ml (total cell count) for T14V, and 2-6 x 10(6)/ml (viable cell count) and 1.5-3 x 10(8)/ml (total cell count) for 34. CONCLUSIONS: Polishing had little effect on adherence. Denture base materials are not resistant against adherence and possible surface damage by oral bacteria. Therefore, thorough oral hygiene is important for denture wearers.

Acrylic Resins↗
PubMed1999

The influence of oral bacteria on the surfaces of resin-based dental restorative materials--an in vitro study.

Three tooth-coloured, resin-based restorative materials (Charisma, Dyract, and Pertac) were exposed to typical oral bacteria (S. mutans, S. oralis and A. naeslundii) over a period of up to 35 days. The three strains of bacteria all colonised the resin-based materials within a few hours and formed thick bacterial films. Determination of the bacterial glucose consumption and lactate production during the incubation period showed no difference from the controls which contained no resin samples. Following the experimental exposure, the materials were examined by scanning electron microscopy (SEM) for possible surface damage and roughness was measured in a perthometer. Little damage to the resin-based composite material surfaces (Charisma, Pertac) could be observed, whereas the polyacid-modified composite material (Dyract) showed greater damage. There was a significant difference in the resin surface roughness after exposure to S. mutans and to A. naeslundii. The study clearly showed that the bacteria used strongly adhered to the resin-based restorative materials. As a consequence of bacterial colonisation and/or poor oral hygiene, damage to the restorative materials might develop. This suggests the need for dentists to evaluate personal oral hygiene, along with general indications and economic factors, in selecting materials for restorations, since the known anti-bacterial properties of amalgam are considerable.

Actinomyces↗
PubMed1998

Retentive strengths of cast gold crowns using glass ionomer, compomer, or resin cement.

PURPOSE: The retention forces of a newly developed compomer cement (Dyract Cem), a glass ionomer cement (Ketac Cem Aplicap), and a resin cement (F21) were examined. MATERIAL AND METHODS: Cemented cast gold crowns were removed along the path of insertion with a Zwick universal testing device. The impact of both a cured and a noncured additional bonding layer that were applied to the inner surface of the crowns was examined across the Dyract Cem group. RESULTS: The mean adhesive strength was measured at 2.36 +/- 0.69 N/mm2 in the Ketac Cem group, at 0.60 +/- 0.28 N/mm2 in the F21 group, and at 1.85 +/- 0.94 N/mm2 in the Dyract Cem group, respectively. The application of an additional bonding layer to the inner surface of the crowns did not significantly improve the retentive strength of Dyract Cem; the respective mean strengths were observed at 1.46 +/-0.33 N/mm2 for the uncured and at 1.70 +/- 0.76 N/mm2 for the cured bonding layers. CONCLUSIONS: Dyract Cem and Ketac Cem showed significantly higher retentive strengths than F21 (p < 0.001, Wilcoxon test, 5% level). No significant difference was found in bond strength between Ketac Cem and Dyract Cem.

Adhesiveness↗
PubMed1990

[Investigation of accuracy of fit of partial crowns with different shaped margins].

The marginal adaptation of partial crowns with different types of finish line preparations was determined by means of dye penetration tests. The best marginal sealing was found for the featheredge-like preparation, followed by the shoulder preparation and the chamfer preparation with or without bevel. The scanning electron microscopic evaluation revealed that a finishing of the restoration margins during the setting of the luting material resulted in a better marginal sealing than a finishing after the cementation.

Adult↗
PubMed1990

[Non-precious metal dental alloys in laboratory tests--critical judgement of results].

An in vitro corrosion investigation of 15 dental NEM alloys respecting the solubility of Ni and Co and the surface destruction shows that results can be interpreted only in combination of visual and SEM investigations. With these results it is possible to make a selection for clinical application. The inverse voltammetry is a sensitive quantitative method for very small amounts of ions in solutions.

Chromium Alloys↗