[Nickel allergy and orthodontics]. / Nikkelallergie en orthodontie.

Nickel hypersensitivity is a common problem, especially among young females, with a prevalence of 5 to 10%, increasing to 30%. In comparison with the oral mucosa, skin is more sensitive to an allergic reaction. The oral mucosa is less sensitive to nickel due to the difference in anatomical structure and the presence of pellicle. Nickel is used in many orthodontic appliances. Due to corrosion nickel ions can be released into the oral cavity. The extent of the corrosion of the appliance depends on the pH, the composition of saliva and plaque, temperature and mechanical loading. In spite of the relatively high amount of nickel processed in orthodontic appliances nickel allergies are rare. In cases of nickel-hypersensitivity, nickel-free appliances should be used.

A method to improve the nutritional quality of foods and beverages based on dietary recommendations.

OBJECTIVE: The increasing consumer interest in health prompted Unilever to develop a globally applicable method (Nutrition Score) to evaluate and improve the nutritional composition of its foods and beverages portfolio. METHODS: Based on (inter)national dietary recommendations, generic benchmarks were developed to evaluate foods and beverages on their content of trans fatty acids, saturated fatty acids, sodium and sugars. High intakes of these key nutrients are associated with undesirable health effects. In principle, the developed generic benchmarks can be applied globally for any food and beverage product. Product category-specific benchmarks were developed when it was not feasible to meet generic benchmarks because of technological and/or taste factors. RESULTS: The whole Unilever global foods and beverages portfolio has been evaluated and actions have been taken to improve the nutritional quality. The advantages of this method over other initiatives to assess the nutritional quality of foods are that it is based on the latest nutritional scientific insights and its global applicability. CONCLUSIONS: The Nutrition Score is the first simple, transparent and straightforward method that can be applied globally and across all food and beverage categories to evaluate the nutritional composition. It can help food manufacturers to improve the nutritional value of their products. In addition, the Nutrition Score can be a starting point for a powerful health indicator front-of-pack. This can have a significant positive impact on public health, especially when implemented by all food manufacturers.

Visceral fat accumulation in relation to sex hormones in obese men and women undergoing weight loss therapy.

In 70 healthy obese subjects (37 men and 33 premenopausal women; aged 27-51 yr; body mass index, 28-38 kg/m2), associations between the initial amount of visceral fat and sex hormone levels were studied as well as between changes that occurred in response to a 4.2 mJ/day deficit diet for 13 weeks. Magnetic resonance imaging was used to quantify the visceral fat depot. In women, an abundance of visceral fat was significantly associated with diminished levels of sex hormone-binding globulin and free 17 beta-estradiol/free testosterone (T) ratio and to elevated levels of free T after adjustment for age and total fat mass. In men, no significant relationships could be found between visceral fat accumulation and any of the sex hormones. Mean total fat loss was 11.3 +/- 3.3 (+/- SD) kg. In women, loss of visceral fat was significantly related to rises in the sex hormone-binding globulin level and the free 17 beta-estradiol/free T ratio independent of total fat loss, whereas in men, only the association between visceral fat loss and increased estrone level reached statistical significance. In conclusion, in obese premenopausal women, visceral fat predominance seems to be related to a relatively increased androgenicity. In obese men, sex steroid levels appear not to depend on the amount of visceral fat. In obese women, but not in obese men, visceral fat loss seems to be accompanied by a relative reduction in androgenicity.

Effect of a weight cycle on visceral fat accumulation.

Magnetic resonance imaging was used to study the effect of a single weight cycle on three fat depots: the visceral and subcutaneous abdominal depots and the subcutaneous depot at the trochanter level. Obese subjects (17 men, 15 women) were examined before and after weight-loss intervention and 67 wk after intervention. They lost 12.9 +/- 3.3 (mean +/- SD) kg body wt during intervention and regained 11.9 +/- 5.1 kg during follow-up. Weight regain did not result in greater body fatness than before weight loss (initial fat mass: 34.3 +/- 6.1 kg, final fat mass: 32.8 +/- 7.7 kg; P = 0.047). There was no indication of a preferential deposition of visceral fat after weight regain (initial visceral fat area: 120 +/- 41 cm2, final visceral fat area: 110 +/- 48 cm2; P = 0.087). On the contrary, there was a slight tendency to accumulate subcutaneous fat at the expense of visceral fat. It is concluded that weight loss followed by weight regain neither leads to a greater body fatness nor to a larger amount of visceral fat compared with before weight loss.

Waist-hip ratio is a poor predictor of changes in visceral fat.

Magnetic resonance imaging was used to study the effect of weight loss on three fat depots: the visceral and subcutaneous abdominal depots and the subcutaneous depot at trochanter level. Changes in fat depots were compared with changes in circumference measures and the waist-hip ratio (WHR) in obese men (n = 38) and women (n = 40). Mean weight loss was (mean +/- SD) 12.9 +/- 3.5 kg (P < 0.001). The proportional reduction of fat was largest in the visceral depot (men 40%, women 33%). Less fat was lost subcutaneously, especially at trochanter level (men 29%, women 26%). WHR decreased significantly in both sexes (P < 0.001). Change in WHR was not significantly related to the absolute reduction in visceral fat. Total body-fat loss showed a stronger association with subcutaneous fat loss than with visceral fat loss. The findings suggest that fat distribution may change with weight loss, particularly by the loss of visceral fat, but changes in WHR are not appropriate for evaluating changes in this fat depot.

Amount of fat in the diet affects bioavailability of lutein esters but not of alpha-carotene, beta-carotene, and vitamin E in humans.

BACKGROUND: Fat-soluble vitamin E and carotenoids are regarded as being protective against chronic diseases. Little is known about the effect of dietary fat on the bioavailability of these compounds. OBJECTIVE: The objective of this study was to assess the effect of the amount of dietary fat on plasma concentrations of vitamin E and carotenoids after supplementation with these compounds. DESIGN: During two 7-d periods, 4 groups of 14-15 volunteers received daily, with a low-fat hot meal, 1 of 4 different supplements: vitamin E (50 mg), alpha- plus beta-carotene (8 mg), lutein esters (8 mg lutein), or placebo. The supplements were provided in a low- or high-fat spread supplied in random sequence during either of the 2 experimental periods. RESULTS: As anticipated, plasma concentrations of vitamin E, alpha- and beta-carotene, and lutein were significantly higher in the supplemented groups than in the placebo group. The amount of dietary fat consumed with the hot meal (3 or 36 g) did not affect the increases in plasma concentrations of vitamin E (20% increase with the low-fat spread and 23% increase with the high-fat spread) or alpha- and beta-carotene (315% and 139% with the low-fat spread and 226% and 108% with the high-fat spread). The plasma lutein response was higher when lutein esters were consumed with the high-fat spread (207% increase) than with the low-fat spread (88% increase). CONCLUSION: Optimal uptake of vitamin E and alpha- and beta-carotene requires a limited amount of fat whereas the amount of fat required for optimal intestinal uptake of lutein esters is higher. 2000;71:-93.

Visceral fat accumulation measured by magnetic resonance imaging in relation to serum lipids in obese men and women.

In 91 apparently healthy obese subjects (45 premenopausal women and 46 men) the associations between specific fat depots and serum lipids were studied. Magnetic resonance imaging was used to quantify fat depots at abdominal and hip level. In women, an accumulation of visceral fat was associated with a less favourable lipid profile, even after adjustment for age and body fat percentage: higher triglycerides levels (P less than 0.001), lower levels of HDL-cholesterol (P less than 0.01) and a diminished HDL-cholesterol/LDL-cholesterol ratio (P less than 0.01). In men, however, the significant inverse relationship between an abundance of visceral fat and the HDL-cholesterol/LDL-cholesterol ratio and the significant positive correlations with total-, LDL-cholesterol and triglycerides disappeared after adjustment for age and fat percentage. Within each sex, subcutaneous fat neither at abdominal level nor at hip level was significantly related to serum lipids. It is concluded that there are gender differences in the associations between visceral fat accumulation and serum lipids.

Relationship between visceral fat and PAI-1 in overweight men and women before and after weight loss.

This study was aimed at evaluating the relationship between visceral fat accumulation and plasma plasminogen activator inhibitor-1 (PAI-1) levels in healthy, obese men and women undergoing weight loss therapy. The subjects, 25 men and 25 premenopausal women, aged between 26 and 49 years, with an initial body mass index between 28 and 38 kg/m2, received a controlled diet for 13 weeks providing a 4.2 MJ/day energy deficit. Magnetic resonance imaging was used to measure visceral and subcutaneous abdominal fat. Our results show that before weight loss visceral fat was significantly correlated with PAI-1 in men (r = 0.45; p<0.05), but not in women (r = -0.15; ns). The association between visceral fat and PAI-1 in men remained significant after adjustment for age and total fat mass, and multiple linear regression analysis showed a significant independent contribution of visceral fat to plasma PAI-1 levels. Both visceral fat areas and PAI-1 levels decreased significantly with weight loss in both men and women. Changes in visceral fat area were related to changes in PAI-1 in women (r = -0.43; p = 0.05) but not in men (r = -0.01; ns); however, this association in women disappeared after adjustment for total fat mass. We conclude that there is a relationship between visceral fat and PAI-1 in obese men but not in obese women, and that PAI-1 levels decrease substantially (52%) by weight loss, but this change is not related to changes in visceral fat mass per se.

Effect of consumption of phenols from olives and extra virgin olive oil on LDL oxidizability in healthy humans.

A high intake of olive oil has been proposed as an explanation for the low incidence of coronary heart disease in Mediterranean countries, but it is unclear whether olive oil offers specific benefits beyond a low content of saturated fat. Some types of extra virgin olive oil are rich in non-polar phenols, which might be taken up by plasma LDL particles and protect these from becoming atherogenic by oxidative modification. In a pilot study we found that consumption of 47 g fortified olive oil containing 31 mg phenols significantly increased the lag time of LDL oxidation from 112 +/- 5 min before to 130 +/- 7 min 2 h after the meal. However, this study was not controlled, and in the current study we therefore investigated whether olive oil phenols increase the lag time of LDL oxidation in postprandial samples when compared with a control group. Twelve healthy men and women consumed four different olive oil supplements with a meal on four separate occasions: one similar to the supplement in the pilot study (positive control); one containing mainly non-polar olive oil phenols; one containing mainly polar olive oil phenols; and one without phenols (placebo). Lag time significantly increased 2 h after the meals with the positive control (8 +/- 2 min), the polar phenols (8 +/- 2 min), and the placebo (8 +/- 2 min), but not after the non-polar phenols (-0.4 +/- 3 min). Increases were not statistically different between supplements. These results indicate that the lag time of LDL-oxidation is increased after consumption of a meal. This increase is probably due to non-specific meal or time effects and not to phenols from olives or olive oil. Furthermore, these findings stress the need for adequate controlled studies to avoid misinterpretations of the data.

A single dose of tea with or without milk increases plasma antioxidant activity in humans.

OBJECTIVE: To investigate the effect of black and green tea consumption, with and without milk, on the plasma antioxidant activity in humans. DESIGN: In a complete cross-over design, 21 healthy volunteers (10 male, 11 female) received a single dose of black tea, green tea (2 g tea solids in 300 ml water) or water with or without milk. Blood samples were obtained at baseline and at several time points up to 2 h post-tea drinking. Plasma was analysed for total catechins and antioxidant activity, using the ferric reducing ability of plasma (FRAP) assay. RESULTS: Consumption of black tea resulted in a significant increase in plasma antioxidant activity reaching maximal levels at about 60 min. A larger increase was observed after consumption of green tea. As anticipated from the higher catechin concentration in green tea, the rise in plasma total catechins was significantly higher after consumption of green tea when compared to black tea. Addition of milk to black or green tea did not affect the observed increases in plasma antioxidant activity. CONCLUSIONS: Consumption of a single dose of black or green tea induces a significant rise in plasma antioxidant activity in vivo. Addition of milk to tea does not abolish this increase. Whether the observed increases in plasma antioxidant activity after a single dose of tea prevent in vivo oxidative damage remains to be established. European Journal of Clinical Nutrition (2000) 54, 87-92

Body impedance is largely dependent on the intra- and extra-cellular water distribution.

Electrical impedance measurements were performed in fasting blood samples and analysed in relation to packed cell volume and calculated intra- and extra-cellular water distribution. The total blood impedance was shown to be strongly dependent on the ratio of intra-cellular water to total water (r = 0.97, P less than 0.0001). In a group of 515 subjects, with a large variation in age and body composition, the relation between the body impedence corrected for fat-free mass and body height (the specific body impedance) and the calculated ratio of intra-cellular water to total body water, was found to be similar to that in blood. From these observations a regression model was developed and applied to body compositional data of several groups of subjects before and after weight loss caused by water losses. It was possible to calculate at a group level the losses of intra- and extra-cellular water, which confirms the applicability of the model. It is concluded that the validity of the predicted fat-free mass or total body water from body impedance is largely dependent on the water distribution in the measured subjects. This means that age- and sex-specific prediction formulas have to be used for the assessment of the body composition and that the bio-electrical impedance method is only with caution applicable in subjects with a disturbed water distribution as in oedema, pregnancy and dehydration.

In obese subjects the body fat percentage calculated with Siri's formula is an overestimation.

By means of theoretical calculations it is shown that the chemical composition of the fat-free mass is affected by the amount of fat in the body. With increasing fatness the relative amounts of minerals and protein in the fat-free mass will decrease and the relative amount of water will increase. These changes in the chemical composition of the fat-free mass are confirmed by data from the literature. Because minerals and protein are the most dense components in the fat-free mass, and water is the less dense component, the density of the fat-free mass will decrease with increasing body fatness. As a consequence, the normally used computation formula for the calculation of the body fat percentage from whole-body density (Siri's equation) will systematically overestimate the real body fat percentage by as much as 2-4 per cent in severely obese subjects. This overestimation is large enough to correct for in studies on energy metabolism and body composition.

The effect of a natural high-fibre diet on faecal and biliary bile acids, faecal pH and whole-gut transit time in man. A controlled study.

Dietary fibre possibly protects against colonic cancer by effects on bile acid metabolism. We investigated the effect of a natural high-fibre diet on secondary bile acid formation. Twelve healthy subjects on an habitual low-fibre diet (for 4 weeks) consumed a high-fibre menu for 10 weeks (experimental group). A control group of 10 subjects consumed their regular high-fibre diet during this period. Faecal and biliary acid composition, faecal weight, faecal pH and gut transit time were studied before and after 6 and 10 weeks of fibre addition. Changes in the experimental group were compared to changes in the control group. The concentration, but not the excretion, of the secondary faecal bile acids was reduced in the experimental group. Faecal weight increased, faecal pH dropped and gut transit time was not altered. The biliary deoxycholic acid content decreased and the cholic acid content increased after 6 weeks, but returned to baseline values after 10 weeks of fibre addition. This study shows that a natural high-fibre diet lowers secondary faecal bile acid concentration through an increase in stool weight. The 7 alpha-dehydroxylation of primary bile acids is probably not or only transiently inhibited.

Modulating effects of indoles on benzo[a]pyrene-induced sister chromatid exchanges and the balance between drug-metabolizing enzymes.

The modulating effects of indole-3-carbinol (I3C) and indole-3-acetonitrile (I3A) on sister chromatid exchange (SCE) induction by benzo[a]pyrene (B[a]P) was studied. Pretreatment of cultured primary chick-embryo hepatocytes with I3C and I3A resulted in a decrease in the number of B[a]P-induced SCEs for both compounds in co-cultured V79 Chinese hamster cells. At 25 µg/ml I3C caused a twofold increase in UDP-glucuronyltransferase (UDPGT) activity. No induction of glutathione-S-transferase was found. When I3A was used (35 µg/ml), UDPGT was increased twofold whereas again no increase in glutathione-S-transferase activity was observed. When induction ratios between UDPGT activity and cytochrome P-450 content were studied, induction with both I3C and I3A resulted in ratios (UDPGT activity/cytochrome P-450 content) comparable with the control situation, whereas induction with 3-methylcholanthrene (3-MC) resulted in a considerable decrease in this ratio. Pretreatment with I3C resulted in a considerable increase in the total conversion of B[a]P into water-soluble metabolites. When the relative amounts of the individual metabolites were compared with those obtained after 3-MC pretreatment no significant differences could be observed. The results indicate that modulating effects of indoles are not directly related to induction of cytochrome P-450-associated enzymes.

Combined mandibular vertical ramus and body step osteotomies for correction of unusual skeletal and occlusal anomalies.

A technique is described involving the combined use of mandibular ramus osteotomies and body step osteotomies. The combined use of these osteotomies enables the surgeon to solve some of the most complicated skeletal and occlusal problems. The method has proved to be safe in that no complications have occurred in the 7 patients reported.

Long-term results of segmental repositioning of the maxilla in cleft palate patients without previously grafted alveolo-palatal clefts.

Eleven patients (9 UCLP, 2 BCLP) were treated with segmental osteotomies with or without osteotomies at the Le Fort I level and simultaneous bone grafting of the alveolo-palatal clefts at adult age. These patients were clinically and radiographically evaluated after a mean follow-up period of 59 months (range 39-110 months). One patient showed complete dentoalveolar relapse, whereas the skeletal stability after miniplate fixation proved to be adequate in all cases. Only one patient presented with a persisting oro-nasal fistula. In six cases, the alar base asymmetry had improved to such an extent that further nasal corrections were not necessary. The procedure described is a reliable technique to graft the alveolo-palatal cleft and reposition the dentoalveolar segments simultaneously in those adult cleft palate patients who had no previous alveolar bone grafting.

The prevention of relapse after maxillary osteotomies in cleft palate patients.

The use of segmental osteotomies to treat surgically severe malocclusion in cleft patients is discussed. The coordinated approach by orthodontist and surgeon is advocated and the advantage of such an approach is stressed. The method allows for the simultaneous correction of the skeletal deformity and closure of residual oro-nasal perforation. The relapse tendency in both antero-posterior and transverse dimensions appeared to be minimal as found in this study of 18 patients.

Surgical orthodontic treatment of anterior skeletal open bite using small plate internal fixation. One to five year follow-up.

Thirty-eight patients with skeletal open bite were studied retrospectively to assess stability of surgical-orthodontic treatment when small plate internal fixation was used. 86% of the sample population showed stable clinical results. Follow-up was from 1-5 years. Only 1 patient experienced skeletal relapse (3%) and 5 patients (13%) dento-alveolar relapse. Fifty percent of relapses were due to transverse relapse of orthodontically expanded maxillary arches. No relapse was seen with surgically assisted orthodontic expansion or surgical expansion at the time of osteotomy. Stable results can be achieved in treating skeletal open bite when small plate internal fixation is used and proper consideration given to the cause of skeletal open bite when planning treatment.

Late management of secondarily grafted clefts.

34 patients (40 sides) received alveolo-palatal bone grafts for closure of the residual cleft, thus guiding a lateral incisor or canine into the arch. Long-term follow-up shows that in 41% of the patients uninterrupted arches were achieved with a normal relationship by orthodontic treatment only. 38% needed segmental osteotomies to eliminate the edentulous space, and in only 20% were bridges made to restore the dental arch. 9 (25%) patients still required a Le Fort I advancement osteotomy, despite optimal orthodontic treatment. The use of segmental osteotomies for eliminating edentulous spaces in cleft palate patients is discussed, and their advantage in relation to nasal base support is emphasized. It should be the aim to achieve in every cleft palate patient a complete archform without the need for bridges or removable prostheses. A rational orthodontic-surgical approach to the cleft, lip and palate patient is suggested with respect to naso-maxillary growth and development.

[Diagnosis of dento-skeletal deformities]. / Diagnostiek van dento-skelettale afwijkingen.

The diagnosis of dento-skeletal deformities is discussed. The suggestion has been made to use a simple classification, which leaves room for a descriptive diagnosis. The descriptive diagnosis should include aspects related to the maxillofacial skeleton, the soft tissues and the dentoalveolar part. A soft tissue analysis will help to assess the main deformity which is often a combination of factors, frequently located in both jaws. A recommendation is made to include a physical therapist, speech therapist and psychologist in the team.