Pre-eruptive protein-energy malnutrition and acid solubility of rat molar enamel surfaces

Protein Intake and Oral Health in Older Adults-A Narrative Review

Oral health is vital to general health and well-being for all ages, and as with other chronic conditions, oral health problems increase with age. There is a bi-directional link between nutrition and oral health, in that nutrition affects the health of oral tissues and saliva, and the health of the mouth may affect the foods consumed. Evidence suggests that a healthy diet generally has a positive impact on oral health in older adults. Although studies examining the direct link between oral health and protein intake in older adults are limited, some have explored the relationship via malnutrition, which is also prevalent among older adults. Protein-energy malnutrition (PEM) may be associated with poor oral health, dental caries, enamel hypoplasia, and salivary gland atrophy. This narrative review presents the theoretical evidence on the impact of dietary protein and amino acid composition on oral health, and their combined impact on overall health in older adults.

Malnutrition and dental caries: a review of the literature

Protein-energy malnutrition occurs when there are deficiencies in protein, energy foods or both, relative to a body's needs. This paper reviews the association of early childhood malnutrition with: (1) dental caries, (2) enamel hypoplasia, (3) salivary gland hypofunction, and (4) delayed eruption. Studies suggest that caries of the primary dentition is associated with early childhood malnutrition, though the effect on caries of the permanent dentition has essentially not been studied. Enamel hypoplasia, salivary glandular hypofunction and saliva compositional changes may be mechanisms through which malnutrition is associated with caries, while altered eruption timing may create a challenge in the analysis of age-specific caries rates.

Effect of a Brazilian regional basic diet on the prevalence of caries in rats

The aim of the present study was to determine the effect of a regional basic diet (RBD) on the prevalence of caries in the molar teeth of rats of both sexes aged 23 days. The animals were divided into six groups of 10 rats each receiving the following diets for 30 and 60 days after weaning: RBD, a cariogenic diet, and a commercial diet. The prevalence and penetration of caries in the molar teeth of the rats was then analyzed. The RBD produced caries in 37.5% of the teeth of animals fed 30 days, and in 83.4% of animals fed 60 days, while the cariogenic diet produced caries in 72.5% and 77.5% of the teeth of animals fed 30 and 60 days, respectively. Rats fed the RBD for 30 days had caries in the enamel in 38% of their teeth, 48% had superficial dentin caries, and 7.5% moderate dentin caries. The effect of the RBD did not differ significantly from that of the cariogenic diet in terms of the presence of caries in rats fed 60 days. The penetration depth of the caries produced by the RBD was the same as that produced by the cariogenic diet. Our results show that the RBD has the same cariogenic potential as the cariogenic diet. Since the RBD is the only option for the low-income population, there should be a study of how to compensate for the cariogenicity of this diet.

Biological mechanisms of early childhood caries

The present paper reviews biological issues in early childhood caries (ECC) in light of the current understanding of the field. Despite the general global decline in dental caries in the past decades, ECC has become a significant problem in many developing countries and some minority communities in western industrialized nations. Like other types of caries, ECC is caused by mutans streptococci that ferment dietary carbohydrates to produce acid attacks on susceptible teeth over a period of time. However, while the general etiology of ECC appears similar to that of other types of caries, the predisposing factors are still unclear. The biology of ECC may be modified by several factors unique to young children, related to the implantation of cariogenic bacteria, immaturity of the host defense systems, as well as behavioral patterns associated with feeding and oral hygiene in early childhood.

Effects of protein deficiency and diet consistency on the parotid gland and parotid saliva of rats

Protein deficiency results in an increased susceptibility to dental caries, suggesting that oral host-defense properties are compromised. An important component of oral host defense is salivary gland function, which is affected by both protein deficiency and diet consistency. This study describes the effects on rat parotid gland growth and secretory function induced by feeding rats diets of normal (20%) or moderately low (7%) protein content, provided in either a powdered or solid form. In addition, since protein deficiency may result in a secondary zinc deficiency which, in turn, may affect salivary gland function, the effects of these diets on liver zinc concentration were also measured. From 22 to 47 days of age, rats (18/group) were fed the following diets: normal protein, powdered; normal protein, solid; low protein, powdered; and low protein, solid. With each diet consistency, liver zinc was higher for the normal protein group. Within each protein level, liver zinc was higher for the solid diet. This latter observation suggests that food mastication and the resultant stimulation of salivary gland function may also play a role in zinc metabolism. With the normal-protein diet, parotid gland weight was higher for the solid diet; with the low-protein diet, parotid gland weight was similar for both consistencies and did not differ from that of the group fed the "normal protein, powdered" diet. For both consistencies, parotid saliva protein concentration was greater for malnourished rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Saliva composition in Indian children with chronic protein-energy malnutrition

The composition of paraffin-stimulated and unstimulated whole saliva was compared between two groups of 8-12-year-old Indian children-one group with severe to moderate chronic protein-energy malnutrition (PEM group) and an age- and sex-matched control group with normal protein status or mild PEM. The classification of PEM was based on anthropometric measurements compared with Indian standards. Stimulated saliva was analyzed for the following variables: electrolytes (Na+, K+, Ca2+, Cl-, and PO4(3-)), total protein, hexosamines, fucose, sialic acid, and amylase. Unstimulated saliva samples were analyzed for total protein, salivary and myeloperoxidase, thiocyanate, lactoferrin, lysozyme, a bacteria-agglutinating protein (BAGP), total IgG, total IgA, and specific anti-S. mutans IgA. The results show that the PEM group had a reduced secretion rate of stimulated but not unstimulated saliva. Further, the Ca2+ and Cl- concentrations in stimulated saliva were significantly lower in the PEM group compared with the control group, but the other electrolyte levels were similar. No differences were found in total protein concentration or glycoprotein bound carbohydrates in stimulated saliva between the two groups, but the quantity of total protein secreted per min was reduced by 20% in the PEM group. Significantly lower levels of lactoferrin, BAGP, and anti-S mutans IgA were found in unstimulated saliva from children in the PEM group, but significantly higher levels of total IgG. We conclude that children with severe or moderate PEM, who have reduced secretion rate, buffer capacity, lower Ca2+, and protein secretion in stimulated saliva, also have impaired immunological and agglutinating defense factors in unstimulated saliva.

A longitudinal study of dental caries in the primary teeth of children who suffered from infant malnutrition

A prospective, four-year longitudinal study of 209 Peruvian children was conducted to evaluate the effect of a single malnutrition episode occurring at infancy (i.e., < 1 year of age) on dental caries in the primary teeth. Children were recruited into the study at age 6-11 months after they had suffered from a malnutrition episode and were thus classified by anthropometry as either: (1) Normal; (2) Wasted (low weight for height); (3) Stunted (low height for age); or (4) Stunted and Wasted (S and W). Eruption of the primary teeth was significantly delayed in all malnourished children; however, the effect of stunting--that is, retarded linear growth--was more pronounced and lasted longer than that of wasting or acute malnutrition (i.e., 2.5 vs. 1.5 years, respectively). By age 4 years, children from group 4 (S and W) showed a significantly higher caries experience in the primary teeth than did those in any of the other three groups. In summary, this longitudinal study has confirmed previous studies in animals and indirect epidemiological evidence which had suggested a cause-effect relationship between early malnutrition and increased dental caries.

The effect of prenatal caffeine exposure on the enamel surface of the first molars of newborn rats

Timed-pregnant rats were randomly divided into three groups at day 7 of gestation. A caffeine tablet was implanted subcutaneously in the experimental group and a placebo tablet in the control group. The third group was used as surrogate dams. At birth, eight randomly selected pups born either to the experimental or control dams were placed with surrogate dams that had produced pups on the same day; these were then used in either the experimental or the control group, and so the surrogate dams raised pups that came from either the experimental or control group. At day 22 after birth, the pups were killed, and their first and second maxillary and mandibular molars were removed. They were then placed in a specially designed chamber and exposed to an acid solution. The outflowing acid solution was collected every 20 min and up to 80 min. Then the calcium, phosphorus, and magnesium contents of each fraction were measured. The enamel surfaces of untreated and acid-treated first molars of the caffeine and control groups were examined by scanning electron microscopy. Untreated teeth were powdered and separated into enamel and dentine. Pure enamel samples were examined with a Gandolfi X-ray powder camera to measure the crystallite size. At 20-, 40- and 60-min intervals, calcium and phosphorus contents of the first molars of the caffeine group were significantly higher than those of the control. The enamel surface of the untreated and acid-treated first molars of the caffeine group had significantly different scanning microscopic appearances from those of the non-caffeine untreated and acid-treated control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of maternal caffeine intake during lactation on molar enamel surfaces in new-born rats

Dams were fed normal laboratory chow until delivery. At birth, the litters were combined, and eight pups were randomly assigned to each dam. Dams with the recombined litters were divided into two groups. Dams of group 1 were fed a 20% protein diet as a control; dams of group 2 were fed a 20% protein diet supplemented with caffeine (2 mg/100 g of the dam's weight). On day 22, the dams of group 2 were anaesthetized with ether. They were injected with 2 iu of oxytocin in order to collect milk. Blood was collected from pups and dams to determine its caffeine concentration. The first and second molars were removed from each pup's mandible and maxilla. Radiographs were taken of 10 randomly selected first or second molars from each group. Four randomly selected molars from each litter were placed in a specially designed chamber and bathed with a constant flow of acid solution to determine the amount of mineral dissolved from the enamel surfaces. The remaining non-acid exposed molars were pulverized in freezer mills. A small portion of this powder was then analysed for the total amount of minerals. No differences were found in the radiographic density of enamel between the groups. The amount of dissolved calcium, phosphorus and magnesium from enamel surfaces in the caffeine group was consistently greater than that of the non-caffeine group in the first molars, whereas, in the second molars, there was no difference between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of nutritional status on the age distribution of dental caries in the primary teeth

A cross-sectional study of dental caries in the primary teeth as a function of nutritional status was conducted on 1481 children one to 13 years old in Lima, Perú. Forty-one percent of the children were found to be chronically malnourished (stunted), 3% were acutely malnourished (wasted), and 5% were both stunted and wasted. A plot of decayed, extracted, and filled teeth (deft) vs. age resulted in a bell-shaped curve that was shifted to the right by 2.5 years for malnourished groups, compared with normal children (p less than 0.01). The shift to the right of the age distribution of caries was associated with a delay in both the eruption and exfoliation of the primary teeth in malnourished children. Peak caries activity was significantly higher in wasted and in stunted and wasted children, when compared with normal controls. It is concluded that malnutrition delayed tooth development, affected the age distribution of dental caries, and resulted in increased caries experience in the primary teeth.

The dissolution rate of enamel in acid in developing rat incisors

This study was undertaken to determine the changes in this dissolution rate at different developmental stages after different fluoride dietary regimes. Four groups of Wistar rats received water with 0, 25, 50 and 100 parts/10(6) fluoride respectively for 10 weeks. Six exposed windows of 2 mm2 were prepared on the enamel surface of the upper incisors, corresponding to six different developmental stages. The acid-dissolution rates were determined at each window by using 1.4 M sodium acetate-hydrochloric acid buffer (pH 2.3). The rate of enamel dissolution was highest in the matrix-formation stage and dropped sharply in a step-wise fashion towards the stages of secondary mineralization and iron deposition. The dissolution rate in the maturation stage decreased significantly with increasing intake of fluoride. However, in the pigmented enamel, the opposite occurred. The iron pigmentation or the porosity in this region of fluorosed enamel might be responsible for the change in the dissolution rate of the pigmented enamel.

Uptake of 45Ca from a topically-applied monofluorophosphate sodium fluoride calcium hydroxide dentifrice by rat enamel

Relative 45Ca-uptake in vivo was determined by etchings after dentifrice application between 18 and 22 days of age; uptake increased and the Ca and P that dissolved decreased with application time. The mechanism of 45Ca-uptake from the dentifrice may be due to either isotopic exchange or to the precipitation or crystal growth of calcium and phosphate.

Tooth wear, solubility and fluoride concentration of molar-tooth surfaces in rats maintained on simultaneous or separate intake of food and fluoridated drinking water

Eighty rats, 20 days old, were fed a hard pellet diet and deionized or fluoridated (25 parts/10(6) F-) drinking water respectively for 40 days. Half were maintained on simultaneous food and water intake for 3 h, daily, and the remainder on separate intake of food for 3 h followed by drinking water for 3 h, daily. Scanning electron micrographs of the occlusal surface of right maxillary first molars were used for scoring wear. The mandibular and left maxillary molar surfaces were used for solubility and fluoride concentration determinations. Intake of food and water separately did not affect wear significantly, whereas solubility and fluoride concentration of the molar surfaces were significantly increased. Wear, solubility and fluoride of the molar surfaces respectively were highly significantly increased in the rats provided with fluoridated water. Increase in fluoride uptake is due in part at least to the increase in sites available for uptake due to tooth wear. Acid dissolution of worn tooth-surface enamel is greater than that of intact enamel.

The effect of malnutrition on caries development and saliva composition in the rat

The purpose of this study was to investigate the effect in rats of malnutrition on caries development and on some antibacterial substances in saliva. By gastric intubation, two groups of ten rats each were fed a liquid basic diet (100% diet), and two similar groups were fed the basic diet diluted with an equal volume of water to contain 50% of the nutrients of the basic diet (50% diet). One group on undiluted and one group on the diluted basic diet were offered sucrose as a supplement by mouth 17 times daily, using a programmed feeding machine, and the other two groups were offered starch in a similar manner. The extent and depth of the caries lesions were five times greater in the low-nourished (50% diet) sucrose group in comparison with the group given the undiluted diet supplemented with sucrose. The 50% diet group ate more frequently from the offered supplement. The 50% diet induced lower salivary lactoperoxidase activities, and there was an additive effect of starch as supplement. Higher concentrations of sIgA were found in the saliva of animals fed the 50% diet supplemented with sucrose than in those fed sucrose and the 100% diet. Significantly greater levels of sIgA and IgG were found in the saliva from the 50% diet-sucrose group than in the 50% diet-starch group. Plaque scores differed slightly but not significantly between the groups. The starch group receiving 100% diet showed a slightly lower level of S. mutans infection as compared with the 50% diet-starch group; the caries scores in the starch groups did not differ.

Effect of casein and whey-protein solutions on caries experience and feeding patterns of the rat

Casein (bovine milk phosphoprotein) at 2 per cent (w/v) in drinking water reduced the extent of fissure and smooth-surface caries of male Sprague-Dawley rats consuming a solid cariogenic diet. Whey protein (the non-phosphorylated protein group of bovine milk) also at 2 per cent (w/v) in the drinking water produced a smaller reduction and only of fissure caries. There was no significant difference in salivary-gland function (as determined by protein concentration), or in the amount or frequency of cariogenic diet consumed. The finding that a 2 per cent solution of whey protein reduced the extent of fissure caries in animals consuming a solid diet containing 26 per cent whey protein suggests that the anticariogenic action is mediated by the protein being in solution. These results suggest a topical anticariogenic action for dietary protein.

The production of developmental defects of enamel in the incisor teeth of penned sheep resulting from induced parasitism

Thirty-four sheep were infected with nematode parasites (Trichostrongylus spp. and Ostertagia circumcincta) during central incisor formation. The tooth enamel was examined for defects of mineralization at eruption and compared with that of 14 control sheep. The type and number of parasites given, the duration of the infection and the age of the sheep were varied. Sheep receiving high doses of parasites e.g. 200,000 T. vitrinus + 20,000 O. circumcincta showed severe systemic effects (debilitation, scouring and weight loss) which were of short duration (7-10 days) as the infections were terminated by anthelmintic treatment. Hypoplastic enamel (a break in continuity) was induced in all 5 sheep infected at 8 1/4-9 months of age and demarcated opacities (an alteration in the translucency) in 3 out of 4 sheep infected at 10 months of age. Sheep given 150,000 or 40,000 T. colubriformis showed less obvious systemic effects although the weight loss continued in some sheep for up to 54 days. Although opacities of the enamel in the form of parallel lines, sometimes with localized increase in width or with a diffuse opacity superimposed, were seen by microscopic examination (X 10) of teeth in this group, many of the teeth from the control sheep showed similar lesions. Only the hypoplastic lesions can be attributed with confidence to the experimental manipulations.