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T Imfeld

Publications and source records attributed to T Imfeld.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Oral health: self-care and dental care: strategies for the patient and the practice. A continuing education course of the Division for Preventive Dentistry, Periodontology and Cariology, the Dentistry Institute of the University of Zurich in cooperation with the Clinic for Periodontology and Dental Bridgework, the Dental Clinics of the University of Bern and the Study Club ARP of 29 and 30 October 1993 in Zurich-Regensdorf: A factual summary].

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Dental Care↗
PubMed1993

Evaluation of the efficacy of interdental cleaning devices. How to design a clinical study.

A review of the literature was made, focusing on experimental designs used in clinical studies for assessment of the efficacy of interdental cleaning aids with regard to plaque removal and the prevention of caries and gingivitis. After careful consideration of the pros and cons of published procedures, an experimental design for such studies is proposed.

Clinical Trials as Topic↗
PubMed1993

pH changes in human dental plaque from lactose and milk before and after adaptation.

pH changes in human dental plaque in vivo from lactose and milk have been studied in four separate mouthrinse experiments. (1) pH was measured in plaque samples of 12 subjects before and after 6 weeks of frequent daily mouthrinsing with 10% lactose. The pH decreases were significantly more pronounced after the adaptation period than before (p < 0.001), 4 of the 12 subjects showing about the same low plaque pH from lactose as from glucose. (2) Similar to the previous experiment, frequent daily mouthrinsing with low-fat bovine milk in 10 subjects resulted in more pronounced pH decreases in plaque after an adaptation period of 4 weeks (p < 0.001). (3) Single mouthrinses, without any prior adaptation, with bovine standard milk, human breast milk, lactose-hydrolysed bovine standard milk, 5% lactose and 5% sucrose were compared regarding the effect on plaque pH in 7 subjects. All solutions resulted in pH falls. The most pronounced were found with sucrose, followed by the lactose-hydrolysed milk. (4) Bovine standard milk, 5% lactose and 10% sucrose were compared after a single mouthrinse in 5 subjects using interdental plaque pH wire telemetry. Lactose and milk were fermented more slowly than sucrose. In a separate study, acid production from lactose was also measured in two oral strains each of Streptococcus mutans, Streptococcus salivarius and Streptococcus sanguis. The results from these experiments indicated that at least part of the lactose transport and catabolism in all studied streptococcus strains seems to be regulated by inducible enzymes.

Adaptation, Biological↗
PubMed1993

Efficacy of sweeteners and sugar substitutes in caries prevention.

The caries-preventive efficacy of sweeteners and sugar substitutes is not clearly established on an epidemiological scale. A review of cariogenicity assessments in vitro and in vivo as well as of human clinical caries trials, however, clearly demonstrates that the replacement of sugar by such products has a caries-preventive effect. The clinical relevance of some bacteriostatic and/or cariostatic properties ascribed to saccharin, aspartame, and xylitol remains to be corroborated.

Aspartame↗
PubMed1993

Comparison of three different methods for measurement of plaque-pH in humans after consumption of soft bread and potato chips.

Three different techniques for measurement of plaque-pH--the sampling, the microtouch, and the telemetric methods--were compared after subjects had consumed different starch products. Ten volunteers, equipped with partial lower prostheses, incorporating a miniature glass pH electrode, refrained from toothbrushing for 3 days. Four products were tested: (1) soft bread, (2) potato chips, (3) 5% starch, and (4) 5% sucrose. The pH of plaque was measured for 45 min by means of all three of the methods. The results showed that the mean pH at 10 min was 1.5 units lower with the telemetric than with the sampling method and 1.0 unit lower with the telemetric than with the microtouch method. Relatively small differences were found among the effects of the four test products for all three methods, with the clearest distinctions among the pH curves being with the microtouch and telemetric methods. The main conclusions from the present investigation are: (1) that there were large differences in pH levels measured with the sampling, the microtouch, and the telemetric methods, even though they ranked the test products in about the same order, and (2) that the two starchy foods, bread and potato chips, were both easily fermented by dental plaque.

Aged↗
PubMed1993

[Fluoride gels--local application with a tray or a toothbrush?].

Fluoride gels have been used since the 1960s. Most gels are recommended for use in mouth-trays. An alternative is the application on a toothbrush. The present study compared the fluoride concentration in surface enamel and its acid resistance following the application in a tray or on a toothbrush in vitro. In a first experiment 80 halves of molar crowns were used. In group A 20 were coated with fluoride gel. In group B 20 were brushed with gel. 20 each served as water control. The surface fluoride concentration and acid resistance of all samples were assessed using an acid etch technique. In a second experiment 30 halves of molar crowns were used. 10 were mounted in a plaster socket mimicking a dental arch for which a customized miniplast-tray was made. This tray was loaded with 1 g of gel and applied for 3 min on 3 consecutive days. 10 samples were brushed for 3 min on 3 days using 1 g of gel and 10 served as water control. Enamel that had been fluoridated with gel on a toothbrush showed a superior acid resistance. The fluoride concentration in the outer 20 to 25 microns of enamel was higher after gel application on a toothbrush than after tray application.

Acid Etching, Dental↗
PubMed1993

Self-adjusting abrasiveness: a new technology for prophylaxis pastes.

An ideal prophylaxis paste should have both cleaning and polishing properties. Key elements would be abrasive particles that become less aggressive under load. The abrasive perlite, a volcanic glass with a sheetlike geometry, is claimed to have these unique properties. This study evaluated the average particle size, size distribution, and morphology of perlite in raw form, in an unused prophylaxis paste, and a used prophylaxis paste. The surface roughness induced on enamel and dentinal specimens was quantitated after paste application in either a rubber cup or a nylon brush. Flour of pumice, a standard prophylaxis paste, a polishing paste, and water were tested similarly. The luster induced by the tested pastes and controls was assessed. Perlite blunted and disintegrated under load. The perlite-containing prophylaxis paste acted as a fine or superfine prophylaxis paste, although it was ranked as medium, based on the mean particle size of its abrasive in the fresh, unused form. Perlite might provide the properties required for the abrasive material of an ideal prophylaxis paste.

Aluminum Oxide↗
PubMed1993

Comparison of the efficacy of prophylaxis pastes with conventional abrasives or a new self-adjusting abrasive.

A newly developed prophylaxis paste that contains perlite as an abrasive medium (Cleanic) was compared to conventional prophylaxis pastes with regard to relative dentin and enamel abrasion, cleaning ability, and polishing power. Rubber cups and nylon brushes were used as paste carriers. Water, flour of pumice, and the dentin-polishing paste CCS 40 served as controls. The tested prophylaxis pastes, selected according to their popularity among clinicians, were CCS 250, Détartrine Z, Nupro Coarse, and Zircate. The Prophylaxis Paste Index was created to assess the clinical potential of the various prophylaxis pastes more accurately. The Index was computed for dentin as cleaning ability dended by relative dentin abrasion x surface roughness (in Ra) x 10, and for enamel as cleaning ability dended by relative enamel abrasion x surface abrasion (in Ra). On dentin and enamel, Cleanic consistently yielded low relative dentin and enamel abrasion values, a good cleaning ability, and low surface roughness scores with both rubber cups and nylon brushes. Of all tested prophylaxis pastes, Cleanic excelled in the Prophylaxis Paste Index on dentin and enamel and with both rubber cup and nylon brush applications. Therefore, a perlite-containing prophylaxis paste has broad professional therapeutic indications and may be used universally as a single paste to clean and polish both dentin and enamel.

Aluminum Oxide↗
PubMed1992

A critical comparison of dentifrice abrasion scores on dentine recorded by gravimetric and radiotracer methods.

Dentifrice abrasivity on dentine is conventionally ranked by various in vitro methods. The abrasivity of selected dentifrices in Switzerland was ranked in 1985 by the gravimetric and in 1989 by the radiotracer method. Because same-named brands of dentifrices were differently ranked by these methods, Swiss clinicians were unsure which ranking to follow. This paper lists the errors known to occur in both techniques, but unfortunately it is difficult to quantitate the magnitudes of these errors. Consequently, it is impossible to determine which method yields the more reliable results. Thus, researchers should look into the problem of dentifrice abrasion scores and try to formulate tests which could simplify the selection of brand-named dentifrices by clinicians and the consumers.

Densitometry↗
PubMed1992

["Safe for Teeth" confectionery and the International Sympadent Federation].

Preventive cariology has primarily focused on the protection of teeth with fluorides and on oral hygiene. Another important preventive approach, namely diet modification reducing the frequency of consumption of acid-producing carbohydrates has not yet gained enough attention. It can very well be implemented by making available a wide variety of non- or hypo-acidogenic snacks. This paper presents a model system, the Swiss Sympadent Association, initiated and currently used in Switzerland for developing, testing, labelling and promoting "tooth-friendly" foods that do not give rise to intraplaque acid production. Based on the success of the Association in Switzerland, an international extension of this model is well on its way.

Cariogenic Agents↗
PubMed1992

[Dental status in relation to age: research in Switzerland 1980-1990].

The number of missing teeth in relation to the patients' age was assessed in fourteen studies of the oral status of different patient groups performed in Switzerland and published between 1980 and 1990. The prognosis of the future development of the average dentition made by Marthaler in 1978 proved to hold true.

Age Factors↗
PubMed1991

Cariogenicity of Milchschnitte (Ferrero GmbH) and apple in program-fed rats.

The cariogenicity of Ferrero Milchschnitte and apple was tested in rats using a frequency-controlled feeding machine. Twelve litters of Osborne-Mendel rats orally infected with Streptococcus sobrinus OMZ-176 and Actinomyces viscosus Ny-1 were used. Four treatment groups were tested: (1) cooked starch/sucrose 1:1 as positive control; (2) Ferrero Milchschnitte; (3) apple; (4) gastric intubation only as negative control. Groups 1-3 were additionally fed by gastric intubation with essential nutrients. Rats on Milchschnitte and apple had less fissure and smooth-surface caries than rats on a starch/sucrose diet, but significantly more than the negative controls. The Milchschnitte group exhibited less plaque extent than the positive and the negative control. The apple group showed a higher plaque extent and massively extended erosions on molar surfaces. The CFU means of S. sobrinus were decreasing from treatment 1-4. Although differences between treatments were not significant, they were associated by concomitantly decreasing caries incidence. The test foods were also assessed using intraoral plaque-pH telemetry in 6 human volunteers. Both Milchschnitte and apple were acidogenic in human telemetry. They can therefore not be regarded as safe for teeth.

Animal Feed↗
PubMed1991

Enamel remineralization: how to explain it to patients.

The term remineralization of initial enamel caries is frequently used, but mainly at research conferences and in lecture rooms. Clinicians avoid discussing remineralization and white-spot enamel lesion formation with patients because details of the processes are complex. Patients, therefore, incorrectly assume that cavitation occurs right at the onset of caries and that a restoration must be placed to halt further progression of the lesion. Although laboratory and clinical studies have shown that initial white-spot enamel lesions can remineralize, patients have little or no access to this information. The schematic diagrams in this paper explain the diffusion of organic acids from plaque between enamel crystals, the partial loss of mineral from enamel crystals, and subsequent demineralization and remineralization that produces the white-spot lesion. Further, these diagrams may help clinicians explain remineralization as simply as possible to patients who present with white-spot enamel lesions.

Dental Caries↗
PubMed1991

[The hydrodynamic behavior of dentinal tubule fluid under occlusal loading].

In an in-vitro study, the fluid movements were quantitatively recorded in natural teeth incorporated rigidly in a closed measuring system and exposed to an occlusal load of 122.6 N. Fluid movements under load are the result of elastic deformations of the tooth. Occlusal loads which were repeated within a short period of time caused a reversible plastic deformation. In comparison to the unfilled tooth the placement of an MOD restoration combined with a glass ionomer cement base caused the following alterations in fluid movements: composite inlay -24.7%, ceramic inlay +34.7%, MOD amalgam -3.1%; the placement of the base per se induced a reduction of -12.7%. In this in-vitro study, the physical properties of the restorative materials governed the magnitude of the fluid movements under load. The results are in contradiction to clinical findings and favor the pulpitis-related genesis of postoperative sensitivity. The intratubular and intrapulpal fluid movements under occlusal load simply seem to trigger the pain sensation.

Biomechanical Phenomena↗
PubMed1990

[Cremation and the environmental mercury burden].

The dental status of 130 deceased Zurich people was evaluated from radiographs of their maxillary and mandibular dentitions taken during their autopsies. A mean mass of mercury of 2.49 +/- 0.37 g was calculated per dentate deceased based on the analysis of 134 extracted premolars and molars with amalgam restorations. The mercury contamination due to cremation in 1988 in Switzerland was calculated to vary between 45.8 and 79.0 kg, based on both the data from the sample analyzed and the fact that 55.5% of Swiss funerals were cremations, the average age of death was 73 and that 70% of the people of that age retained some of their teeth. Mercury contamination by cremation, therefore comprised only 0.61 to 1.53% of the total mercury contamination produced by all waste incineration methods. The minimal contribution to the mercury contamination due to cremation can thus not be used as an argument to ban the use of dental amalgams.

Air Pollutants↗