Casein fraction of cow's milk and sheep's milk are very similar in their immunological behavior. Therefore, in the presence of sheep's milk, precipitation reaction with commercially obtained serum are not specific. Results from comparative immunoelectrophoresis according to Grabar and Williams also are equivocal, for heat and other denaturing factors caused shifts in the pattern of just the small group of differing elecrophoretic bonds present among many identical bonds. Qualitative identification of large amounts of cow's milk added to sheep's milk or of bovine casein to sheep cheese or similar products are possible in principle by two dimensional immunoelectrophoresis or so called crossed immunoelectrophoresis as described by Clarke and Freeman, but this estimation takes a lot of time and is not suitable for analysis of a series of samples. Sufficient sensitivity for certain and semiquantitative statements about the content of cows' milk casein in products from sheep's milk are obtained by the technique of radial double diffusion by Ouchterlony in Agarose gels only by the saturation of commercial anti-bovine-casein-serum by means of a suitable protein-standardized sheep's milk extract and its subsequent work-up and lyophilisation to yield a stable serum.

Animals↗

PubMed1980

[Determination of saxitoxin in canned shellfish (author's transl)].

Poisonings by saxitoxin-containing shellfish occur regularly in shore areas. The reason is increased growth of the dinoflagellates Gonyaulax tamarensis and Gonyaulax catenella. Due to the widespread consumption of canned shellfish these kinds of poisoning also occurs in continental areas. Therefore it is necessary to determine saxitoxin in canned shellfish products. Because of their sensitivity fluorospectrophotometric determinations of saxitoxin are preferred. However, the methods described in the literature can only be applied to fresh shellfish. Consequently a method for the determination of saxitoxin in canned shellfish was developed. This method offers the advantage that parallel with the fluorophotometric determination a biotest with mice can be carried out with the same extract for forensic corroboration of the results. The extent of saxitoxin occurence in Spanish canned shellfish in Austria in the years 1976-1979 is described. Apparently the producers of canned shellfish were able to solve this problem since mid - 1978.

Animals↗

PubMedDate not supplied

Use of variable remineralization periods to improve the abrasion resistance of previously eroded enamel.

The objective of the study was to evaluate the period of remineralization needed to re-establish the resistance of eroded enamel against brushing abrasion. Enamel specimens were prepared from 84 polished bovine incisors. The samples were evenly distributed among 7 groups (A-G) and submitted to ten alternating de- and remineralization cycles which included abrasion by toothbrushing. Demineralization was accomplished by immersing the specimens in the erosive soft drink Sprite Light((R)) for 1 min. Remineralization was performed by storing the samples in artificial saliva for either 0 min (A), 10 min (B), 60 min (C) or 240 min (D). After each remineralization, the specimens were brushed in an automatic brushing machine. Group E (erosion and 240 min remineralization, but no brushing) group F (erosion, but no remineralization and no brushing), and group G (brushing, but no erosion and no remineralization) served as controls. After performing the cycles, loss of enamel was determined by profilometry. The following values (mean +/- SD) were obtained and statistically analyzed (p<0.05): group A (5.16+/-1.26 microm), B (2.47+/-0.68 microm), C (1.72+/-0.75 microm), D (1.11+/-0.42 microm), E (0.81+/-0. 23 microm), F (1.04+/-0.31 microm), G (0.22+/-0.15 microm). Only the differences between groups D, E, and F were statistically not significant. Under the chosen in vitro conditions, it is concluded that abrasion resistance of eroded enamel continuously increases with remineralization time. However, even after a period of 1 h of remineralization, abrasion of previously eroded enamel is increased

Analysis of Variance↗

PubMedDate not supplied

Clinical evaluation of chemomechanical caries removal in primary molars and its acceptance by patients.

The purpose of this study was to evaluate the clinical efficiency and patient acceptance of the chemomechanical caries removal agent Carisolvtrade mark in deciduous teeth. Contralateral primary molars of sixteen 7- to 9-year-old patients (32 teeth) were treated with the air-motor and with Carisolv, respectively. Patients replied to a pre- and a postoperative questionnaire. Complete caries removal (CCR) was accomplished in all air-motor sessions. It was not achieved within the time limit of 15 min in 6 (37.5%) Carisolv sessions. Air-motor CCR time ranged between 6 and 18 s (mean: 11.81 s ). Carisolv CCR time, where accomplished within 15 min, ranged between 6 min 46 s and 13 min 57 s (mean: 6 min 51 s). Preoperatively, the majority of the children reported disliking the drilling, and that they would visit the dentist more often and prefer sitting in the chair longer if they could avoid it. Postoperatively, the majority of the children reported disliking the taste of Carisolv, estimated Carisolv to have taken longer, would not recommend it to their friends, and preferred the air-motor. In conclusion, Carisolv, although a step forward in terms of solution volume required, is not in a position to replace rotary instruments for caries removal: it did not remove decay completely in one third of our sample; it was much slower than the air-motor; it had a chlorine taste/odor our patients disliked.

Air Abrasion, Dental↗

PubMedDate not supplied

Influence of olive oil emulsions on dentin demineralization in vitro.

The effect of two different concentrations of olive oil emulsions on development of artificial caries-like dentin lesions under severe demineralizing conditions was investigated. Bovine dentin samples (n = 180) were ground flat, polished, divided into four groups, and subjected to three demineralization cycles per day. Samples were stored in one of the following solutions for 5 min prior to demineralization in a buffer solution (pH 5): Group 1: 50% oil emulsion (olive oil and distilled water); group 2: 5% oil emulsion; group 3: distilled water; and group 4: 1,500 ppm sodium fluoride. Daily up to 9 days, lesion depth (ld) and mineral loss (deltaZ) were determined by means of microradiography and analyzed by ANOVA and Tukey's studentized range test (p < or = 0.05). Lesion depth increased with time for all groups. Mineral loss increased in groups 1-3. A small but significant decrease in mineral loss was observed following treatment with lipid emulsions as compared to treatment with distilled water, but fluoride treatment was considerably more effective. Mean mineral loss (means +/- SD in vol% x microm) averaged over the study period was 4,368 +/- 1,599, 4,536 +/- 1,823, 4,849 +/- 1,798, and 789 +/- 177 for group 1, 2, 3, and 4, respectively. Ratio (deltaZ/ld) remained constant around 30 vol% for groups 1-3, but decreased for group 4. In conclusion, externally provided lipids have the potential to reduce dentin demineralization in vitro.

Analysis of Variance↗

PubMedDate not supplied

Systemic versus topical fluoride.

The actual mechanism of fluoride action is still a subject of debate. A dogma has existed for many decades, that fluoride has to be ingested and acts mainly pre-eruptively. However, recent studies concerning the systemic effect of fluoride supplementation concluded that the caries-preventive effect of fluoride is almost exclusively posteruptive. Moreover, epidemiologists have cast doubt on the validity of the 'old' studies dealing with fluoride use. The concept of the posteruptive fluoride effect is supported by in vitro and in situ investigations demonstrating that the mode of action of fluoride can be attributed mainly to its influence on de- and remineralization kinetics of dental hard tissues. Therefore, topical fluoride application (e.g. in the form of fluoridated dentifrices) should be encouraged. There are still important questions open that need to be answered despite existing knowledge about the caries-preventive effect of fluoride.

Administration, Oral↗

PubMedDate not supplied

Individual vitality pattern of in situ dental biofilms at different locations in the oral cavity.

The aim of the study was to examine the three-dimensional vitality structure of dental biofilms grown simultaneously at different locations in the oral cavity over a 48-hour period. Eight healthy volunteers wore special acrylic appliances. On each buccal side of the upper and the lower jaw three glass slabs were inserted, allowing for growth of a biofilm mimicking approximal plaque. After 48 h, the specimens were removed and biofilms were stained using two fluorescent dyes which selectively stain vital bacteria green and dead bacteria red. Under the confocal laser scanning microscope optical sections of 1 microm throughout the biofilm were made. To assess the vitality values (proportion of vital bacteria) of the whole biofilm as well as the vitality distribution in the different plaque sections an image analysis program was used. Plaque from the different locations revealed mean vitality values between 64.4 and 75.7% in the upper jaw and between 64.3 and 76.8% in the lower jaw, which were not statistically different. However, a great variation of the vitality values for the different layers and among the 8 subjects was found. Nevertheless, the analysis of the data of each single volunteer revealed a very similar vitality pattern in all twelve locations.

Adult↗

PubMedDate not supplied

Profilometric and microradiographic studies on the effects of toothpaste and acidic gel abrasivity on sound and demineralized bovine dental enamel.

The objective of this study was to assess the abrasive effects of toothpastes and acidic F gels on sound and demineralized enamel. Pairs of enamel specimens were cut from bovine incisors, embedded in epoxy resin and polished. An artificial subsurface lesion of 80-90 microm depth was created in one specimen from each pair. The samples were covered with adhesive tape, thereby exposing the enamel for abrasivity testing. All samples were divided into six groups of 15 and brushed with a slurry (1:3) of F gel or toothpaste and human saliva. Brushing with water (control) or with slurry was carried out (16,000 strokes) using a medium toothbrush (load 275 g) mounted in a brushing machine. Abrasion was evaluated using laser profilometry, and was about 50% less on sound than on demineralized enamel (p < 0.001). In the latter, brushing with water (0.09 +/- 0.03 microm) or with fluoride-free gel (0.08 +/- 0.03 microm) resulted in negligible wear. With a medium-abrasive paste (1.76 +/- 0.85 microm) and an acidic F gel (2.48 +/- 0.72 microm), brushing abrasion was significantly greater (p < 0.001) than with a low-abrasive paste (0.84 +/- 0.38 microm). The greatest wear (16.6 +/- 10.8 microm) was observed with high-abrasive paste (p < 0.001), and here transversal microradiography revealed a complete loss of the pseudointact surface after brushing. In vitro formed caries-like lesions can be abraded (by toothbrushing) more easily than sound enamel; hence, initial white spot lesions should preferably be brushed with oral hygiene products of low abrasivity.

Amines↗

PubMedDate not supplied

Influence of two dentin bonding systems on the demineralization of the root surface.

It has been assumed that dentin adhesives can prevent root surface caries. The aim of this study was to determine the caries-protective effect of two different dentin bonding systems on the demineralization of root surfaces in vitro. The root surfaces of 60 freshly extracted caries-free human molars were thoroughly cleaned and polished, thereby removing the cementum. The teeth were then coated with acid-resistant nail varnish, exposing two rectangular windows of 6 mm2 each. One window served as an untreated control, while the other window was treated with a dentin bonding system. The specimens were distributed among the following experimental groups--Group 1: Syntac, Heliobond (no air thinning); Group 2: Syntac, Heliobond (as recommended); Group 3: Syntac, without Heliobond; Group 4: Prime & Bond 2.0 (no air drying); Group 5: Prime & Bond 2.0 (as recommended); Group 6: Prime & Bond 2.0 (dentin pretreated with 36% phosphoric acid). Subsequently, all specimens were demineralized for 6 days with acidified gel (HEC, pH 4.8, 37 degrees C). From each tooth, three dentinal slabs were cut perpendicular to the polished surface of the windows. The slabs were ground to a thickness of 80 microns and imbibed with water. The depth of the respective demineralized areas was determined using a polarized light microscope. All control specimens exhibited lesions with a mean depth of 67 microns. In Groups 2, 3, and 5 the lesion depth was reduced significantly, while in Groups 1, 4, and 6 no lesions could be detected. It was concluded that the demineralization of the root surface can be impeded by application of the dentin adhesives tested.

Acrylates↗

PubMedDate not supplied

Brushing abrasion of luting cements under neutral and acidic conditions.

Four resin based materials (Compolute Aplicap, ESPE; Variolink Ultra, Vivadent; C&B Metabond, Parkell and Panavia 21, Kuraray), two carboxylate cements (Poly-F Plus, Dentsply DeTrey and Durelon Maxicap, ESPE), two glass-ionomer cements (Fuji I, GC and Ketac-Cem Aplicap, ESPE), one resin-modified glass ionomer cement (Vitremer, 3M) one polyacid-modified resin composite (Dyract Cem, Dentsply DeTrey) and one zinc phosphate cement (Harvard, Richter & Hoffmann) were investigated according to their brushing resistance after storage in neutral and acidic buffer solutions. For this purpose 24 cylindrical acrylic molds were each filled with the materials. After hardening, the samples were stored for seven days in 100% relative humidity and at 37 degrees C. Subsequently, they were ground flat and polished. Then each specimen was covered with an adhesive tape leaving a 4 mm wide window on the cement surface. Twelve samples of each material were stored for 24 hours in a buffer solution with a pH of 6.8. The remaining 12 samples were placed in a buffer with a pH of 3.0. All specimens were then subjected to a three media brushing abrasion (2,000 strokes) in an automatic brushing machine. Storage and brushing were performed three times. After 6,000 brushing strokes per specimen, the tape was removed. Brushing abrasion was measured with a computerized laser profilometer and statistically analyzed with ANOVA and Tukey's Standardized Range Test (p < or = 0.05). The highest brushing abrasion was found for the two carboxylate cements. The lowest brushing abrasion was found for one resin based material, Compolute Aplicap. With the exception of three resin-based materials, a lower pH led to a higher brushing abrasion.

Analysis of Variance↗

PubMedDate not supplied

Fracture toughness of pin-retained class 4 restorations.

Standardized class 4 cavities were prepared in bovine incisors and restored with a microfilled composite resin. The composite restorations were retained either by acid etching technique (AET) alone or by acid etching technique in combination with a self-threading retentive pin. Pins covered with a bonding/opaquer coating (PCR pin) and uncovered pins (FO pin) were used. After having been aged for 3 days, the fracture resistance of the restorations was determined with a Universal Testing Machine. The restorations were loaded at an angle of 45 degrees. The restorations retained by AET and a PCR pin showed the highest failure load. The restorations accomplished with AET and a FO pin yielded the lowest fracture load. The fracture toughness of the restorations retained by AET and a PCR pin was slightly but statistically significant, higher compared to the restorations exclusively attached by acid etching technique. It was concluded that there was only a small increase of fracture toughness of large class 4 composite restorations if the acid etching technique was combined with the application of bonding/opaquer-covered retentive pins.

Acid Etching, Dental↗

PubMedDate not supplied

Microscopic studies of accessory canals in primary molar furcations.

The purpose of this study was to evaluate the incidence of accessory canals in the furcation region of human primary second molars. Forty freshly extracted teeth were radectomized and furcations were separated. The severed pulp chamber floors were decalcified and dehydrated. Paraffin embedding followed and cross-cut serial sections were taken from the specimens. Microscopic examination of each section followed. Sixteen out of twenty (80 percent) of the maxillary and fifteen out of twenty (75 percent) of the mandibular primary second molars demonstrated accessory foramina in the furcation area. 17.3 percent of the accessory foramina were found in the pulp chamber floor and 82. 7 percent were observed interradicular, close to the periodontal ligament. Thirty percent of the primary second molars demonstrated accessory canals, running from the pulp chamber to the periodontal ligament. Within the limitations of a microscopic investigation it is assumed that accessory furcation canals might be responsible for interradicular bone pathology in case of pulpal inflammation or necrosis.

Decalcification Technique↗

PubMedDate not supplied

Diffusion behavior of eugenol from zinc oxide-eugenol mixtures through human and bovine dentin in vitro.

The objective of this in vitro study was to evaluate the long-term diffusion behavior of eugenol from different zinc oxide-eugenol mixtures through thin dentin layers. In 24 freshly extracted, caries-free human teeth standardized cavities were prepared exhibiting a dentin surface area of 7 mm2. The remaining thickness of the dentin close to the pulp chamber amounted to at least 0.2 mm. In a second experiment standardized dentin disks (0.2 mm thick) were prepared from 24 bovine incisors. The disks were embedded in epoxy resin, thus exposing a resin-free, standardized area of 7 mm2. Specimens from both experiments were inserted into a screw cap of a vial. Cp-Cap, Temp Bond, and two zinc oxide-eugenol mixtures (P/L ratios of 10:1 and 2:1) were applied to each of six specimens from both experiments. The opposing surface was in contact with 1 ml of Ringer solution. After 1 day, 7 days, and 21 days respectively, the amount of penetrated eugenol was determined with High-Performance Liquid Chromatography (HPLC). In both experiments we found a persistent release and diffusion of eugenol, irrespective of the applied material. However, for the second experiment, we saw more pronounced diffusion rates. Furthermore, the materials showed significant differences, particularly for low versus high P/L ratios.

Adolescent↗