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Biomedical subjects

D Heidemann

Publications and source records attributed to D Heidemann.

At least 19 recordsLinked to original sources
PubMed1998

Erbium:YAG laser application in caries therapy. Evaluation of patient perception and acceptance.

OBJECTIVES: In previous studies it has been demonstrated that the Er:YAG laser can be used to prepare cavities efficiently and without thermal damage to the adjacent dental hard and soft tissues. To investigate the patients' response to Er:YAG laser preparation of teeth, a prospective clinical study was performed in five dental hospitals. METHODS: To evaluate patients' perception and response to cavity preparation a direct comparison was made between conventional mechanical preparation and Er:YAG laser preparation of caries in dental hard tissues. Half of the preparations were completed by the laser alone with standardized parameters, with the other half being mechanically prepared. The sequential order of treatment was randomized, and clinical parameters such as depth and location of the cavities were carefully balanced. A three-score evaluation scheme of patient responses was used: comfortable, uncomfortable, very uncomfortable. In addition the patients were asked to decide which was the more uncomfortable form of treatment and the preferred treatment for future caries therapy. RESULTS: The study included 103 patients with 206 preparations distributed amongst 194 teeth. All teeth gave vital responses (ice test) before and after both types of treatment. The laser treatment was found to be more comfortable than the mechanical treatment, with high statistical significance. During treatment, the need for local anaesthesia was 11% for mechanical preparation compared to 6% during laser application. It was found that 80% of the patients rated the conventional preparation as more uncomfortable than the laser treatment and 82% of the patients indicated that they would prefer the Er:YAG laser preparation for further caries treatment. CONCLUSIONS: The application of the Er:YAG laser system is a more comfortable alternative or adjunctive method to conventional mechanical cavity preparation.

Adult↗
PubMed1990

[Amalgam?].

Explore the source record for details and available documents.

Body Burden↗
PubMed1989

[Root canal filling--manual and mechanical methods].

A satisfactory apical seal can be achieved with all the methods listed in this article. The result depends on the experience and skill of the operator using his or her standard method. One single method, however, does not always adequately meet the requirements arising from the morphology of the canals, the alignment of the tooth in the dental arch, jaw opening, and the conditions governing the preparations of the root canal. The time saving aspect favors the use of engine-driven instruments. The use of thermomechanical methods and the injection method is limited in the posterior jaw area. Similar to preparation, all methods present difficulties in handling certain situations, such as narrow, curved canals, or wide open foramina in straight canals. The so-called standard methods of manual techniques provide reliable good results in almost any situation.

Dental Pulp Cavity↗
PubMed1989

[Contact pattern of cultivated gingiva cells on different substrates].

The question of contact with the surface of biomaterials has not been fully elucidated. The importance of the surface structure continues to be discussed in terms of the roughness profile. However, it can be demonstrated that surface structure alone is not the crucial parameter for the adhesion or the lack of adhesion of cells. Probably factors like serum coating of a substrate and fibronectin formation of cells are at least as important, if not decisive preconditions for cell adhesion and in particular for the active spreading of cells in contact with biomaterials.

Biocompatible Materials↗
PubMed1989

[Axial compressive strength of amalgam fillings in correlation with cavity preparation].

UNLABELLED: Different types of cavities were prepared in 96 model teeth: simple preparations without ledges and with Amalgapins, slots or a post; proximal box preparations with an occlusal ledge, and box preparations with or without Amalgapins or slots. The amalgam fillings were subjected to axial load by means of a Zwick machine until the filling or the tooth fractured. RESULTS: --Occlusal ledges and box preparations allow high load values. --Surprisingly high loads can be placed on simple preparations without ledges but with a post. --Preparations without ledges but with Amalgapins or slots rate lowest. --In box preparations and preparations with ledges, Amalgapins or slots fail to offer any significant increase in compressive strength.

Dental Amalgam↗
PubMed1987

Corneal ulcer due to Listeria monocytogenes.

We present a patient with a corneal ulcer due to Listeria monocytogenes, which has not previously been considered to be a feature of human listeriosis. The ulcer responded to topical and subconjunctival gentamicin and cephaloridine. Subsequent management was complicated by the development of a fibrinous pupillary membrane leading to pupillary block requiring iridotomy and later vitrectomy with trabeculectomy. Listeria monocytogenes may be confused with diphtheroid contaminants seen in corneal ulcer scrapings and is probably underreported as a cause for microbial keratitis.

Aged↗
PubMed1985

Specular microscopic follow-up of corneal grafts for pseudophakic bullous keratopathy.

Pseudophakic bullous keratopathy (PBK) has become the leading indication for penetrating keratoplasty. In our initial fifty patients having keratoplasty for PBK there was gradual loss of clear grafts in patients with retained intraocular lenses (IOLs). Specular microscopy was performed on donor tissue, and periodically postoperatively, for 130 grafts for PBK. The highest cell loss at one year was in eyes with retained iris support (39.2%) or anterior chamber (37.2%) IOLs. Cell loss in grafts with removed iris support IOLs (21.3%) was significantly less. When iris support IOLs were exchanged for anterior chamber (AC) IOLs, the cell loss at one year (27.1%) was intermediate. We recommend that iris support IOLs be removed at keratoplasty. Exchange for an AC IOL should be considered depending on the visual needs of each patient. Removal of AC IOLs should be based on consideration of prior tolerance and position of the implant.

Aged↗
PubMed1985

Potent antileukemic activity of the novel cytostatic agent avarone and its analogues in vitro and in vivo.

Avarone and avarol are novel cytostatic agents which have potent antileukemic activity both in vitro and in vivo (mice). Cell culture experiments revealed that the cytostatic activity of these two compounds on L5178Y mouse lymphoma cells was 13- to 14-fold higher than that determined for HeLa cells and 40- to 43-fold higher than that for human melanoma cells. Nontumor cells (human fibroblasts and human gingival cells) were highly resistant against the two compounds. The inhibitory potency of avarone on L5178Y cells (50% inhibitory concentration, 0.62 microM) was significantly higher than the avarol activity (50% inhibitory concentration, 0.93 microM). Modification of the molecule at the quinone ring or the double bond in the terpenoid skeleton resulted in a significant loss of activity. In vivo studies with L5178Y cells in the ascites of mice confirmed the strong antileukemic effect determined in vitro. At doses of 10 mg/kg given i.p. once daily for 5 days to mice bearing approximately 10(8) leukemia cells, avarone was found to be curative in about 70% of the mice (20% for avarol). The optimal daily i.p. dose of avarone increased life span over controls by 146% when treatment was begun 1 day after tumor implantation and by 87% when treatment was delayed until day 8. Avarol, although active, was less effective. Based on the determined log10 kill values, avarone can be classified as a highly active and avarol as a markedly active cytostatic agent. The efficacy of the two compounds is also emphasized by the therapeutic index of 11.7 for avarone and of 4.5 for avarol. The two agents were determined not to be either direct mutagens or premutagens in the Ames test.

Animals↗