The relationship between calcium and phosphorus concentrations of human saliva and dental plaque.

A direct relationship between inorganic phosphorus concentrations of stimulated parotid saliva and upper posterior plaque was observed in a preliminary investigation with young adults. A similar relationship was demonstrated for inorganic phosphorus concentrations of stimulated mixed saliva and mature plaque in a two-part study with children. A direct relationship between calcium concentrations of saliva and plaque was also observed. The calcium and inorganic phosphorus concentrations of the plaque were directly related to the flow rate of the stimulated mixed saliva.     

Relationship between total and ionized calcium concentrations in human whole saliva and dental plaque fluid.

Ionized and total calcium were determined with an ion-selective electrode in unstimulated whole saliva and in simultaneously collected plaque fluid. The mean ionic and total concentrations in saliva from 20 subjects were 0.53 and 1.03 mmol/l respectively, and in plaque fluid 0.64 and 1.20 mmol/l. The total calcium concentration in saliva was closely related to the total calcium concentration in plaque fluid (r = 0.95, p less than 0.001) as was the ionized calcium concentration in saliva to that of plaque fluid (r = 0.84, p less than 0.001).     

Fluoride concentrations in saliva and dental plaque in young children after intake of fluoridated milk

This study determined fluoride (F) concentrations in whole saliva and dental plaque after intake of fluoridated milk using a randomised crossover experimental design. Eighteen healthy children (6-8 years) were subjected to each of four different 3-day drinking regimens: (a) 200 ml F-free tap water; (b) 200 ml tap water with 1.0 mg F; (c) 200 ml standard milk, and (d) 200 ml standard milk with 1.0 mg F. A washout period of 7 days was organised between the different drinking regimens. All children used F-free toothpaste prior to and during the trial and were instructed to avoid F-rich food and drinks. F concentration in unstimulated whole saliva was determined at baseline and after 15 and 120 min and in plaque samples at baseline and after 2 h. The mean baseline values ranged from 0.01 to 0.02 mg F/l in saliva and between 10.4 and 14.2 mg F/l in dental plaque. A statistically significant (p < 0.05) increase of F was disclosed in saliva 15 min after drinking F-containing milk and water (0.052 and 0.058 mg F/l, respectively). After 2 h, the salivary F(-) concentrations were back to baseline values. In the plaque, however, a statistically significant (p < 0.01) twofold increase was found at 2 h after the intake of fluoridated milk and water, respectively. The results indicate that consumption of fluoridated milk contributes to a F storing process with significantly elevated F concentrations in dental plaque up to 2 h after intake. Further studies are required to determine the 'therapeutic concentration' of F in dental plaque after intake of fluoridated milk.     

Relationship between dental plaque indices and bacteria in dental plaque and those in saliva

A variety of indices has been developed for the quantitation of dental plaque. The aim of this study was to determine the correlation between the L?e plaque index and the number of bacteria on the same tooth. Furthermore, the effect of plaque accumulation on the salivary counts of some dental plaque organisms was estimated. Twenty volunteers were asked to abstain from all oral hygiene for a one-week period. Clinical indices and bacteriological samples were taken at the start and at the end of the experimental period. After an interval of seven days, the experiment was repeated. The relationship between the L?e plaque index and the total bacterial counts on the same area of the tooth was found to be highly significant. After seven days without oral hygiene, the total counts and the Actinomyces viscosus/naeslundii and Streptococcus sanguis counts in dental plaque had increased by approximately two log units, while the Streptococcus mutans counts had increased by more than one log unit. The large increase in the number of bacteria on the teeth was reflected in the salivary counts of the Actinomyces species, but not in the S. sanguis or S. mutans counts. This was due to differences in ecological habitats of these species in the mouth. Highly significant correlations were found between the S. mutans level in dental plaque and the salivary level, and between the S. mutans counts of the subjects in the first and second trials of the experiment.     

Effect of brushing with fluoride toothpastes on the fluoride, calcium, and inorganic phosphorus concentrations in approximal plaque of young adults

A within-subject cross-over study was carried out to examine whether brushing with fluoride toothpastes would alter the composition of approximal plaque. Approximal plaque was collected from 22 subjects following brushing with toothpastes containing sodium fluoride and sodium monofluorophosphate with calcium glycerophosphate and a fluoride-free control toothpaste. Concentrations of plaque calcium, inorganic phosphorus, and fluoride were estimated. Toothbrushing with the fluoride toothpastes resulted in significantly greater concentrations of fluoride in approximal plaque when compared with the control toothpaste. However, there was no significant difference between the two fluoride toothpastes. The use of the sodium monofluorophosphate containing toothpaste resulted in significantly elevated concentrations of calcium and inorganic phosphorus in approximal plaque when compared to both sodium fluoride and control toothpastes. It was concluded that the use of a fluoride toothpaste can alter the chemical composition of approximal plaque.     

幼儿唾液中的钙含量及其与患龋状况的关系

目的 :探讨幼儿唾液中的离子钙、总钙含量及两者比值与患龋状况的关系。方法 :将 99名 3～ 5岁乳牙列期儿童依据龋患程度分为无龋组、龋病低危组与高危组。采用原子吸收光谱仪 (火焰法 )和离子选择性电极对三组儿童唾液中的总钙含量 (Ca)和离子钙含量 (Ca2 + )分别测定 ,并计算两者比值 (Ca2 + /Ca) ,统计分析此三种指标与患龋状况的关系。结果 :受检乳牙列期儿童唾液中离子钙含量为 (0 .15 8± 0 .0 4 3)mmol/L ,总钙含量 (1.4 36± 0 .30 0 )mmol/L ,离子钙 /总钙含量值为 0 .112。三项指标在性别间无显著性差异(P >0 .0 5 )。唾液离子钙与总钙含量在无龋组、龋病低危组、龋病高危组之间无统计学差异 (P >0 .0 5 ) ,但无龋组的离子钙 /总钙比值高于龋病低危组与高危组 ,有显著性差异 (P <0 .0 5 )。结论 :乳牙列期儿童唾液中离子钙或总钙含量并不能反映个体的龋患状况 ,但离子钙与总钙的比值或可作为评价儿童患龋状况的一个参考指标。     

Critical pH in resting and stimulated whole saliva in groups of children and adults

Objective . The concentrations of calcium and phosphate in saliva have significant influence on the protective mechanisms of dental hard tissues within the oral environment. A lower calcium concentration means: 1) a lower thermodynamic driving force for hydroxyapatite precipitation at normal oral pH; 2) a higher driving force for hydroxyapatite dissolution at low pH; 3) a lower critical pH. The aims of this study were to: 1. determine the calcium and phosphate concentrations 2. calculate the critical pH for enamel and 3. determine the driving forces for demineralization and remineralization in a group of children and adults.
Methods . In this comparative study, calcium and phosphate concentrations were measured in the resting and stimulated saliva of child and adult volunteers using a spectrophotometric system used in routine blood analysis. Salivary flow rates were also measured in each group.
Results . The calcium concentrations were lower in children than adults, but the phosphate concentrations were not significantly different. The critical pH was significantly higher for children than adults in both resting and stimulated saliva. Therefore, the thermodynamic driving forces for; (1) demineralisation at low oral pH, is greater , and (2) for remineralisation at normal oral pH, is lower, in children compared to adults.
Conclusion . The results of this study show that from thermodynamic considerations alone, there is increased risk of demineralization in children compared with adults.     

Relationship between the hexosamines of human saliva and dental plaque

Optimum conditions for hydrolysis of submandibular, sublingual, parotid and whole saliva for the estimation of total hexosamine were determined and the Elson-Morgan method adapted for total hexosamine estimation and for estimation of individual hexosamines after column chromatography. Sublingual saliva contained approximately 200 μg total hexosamine/ml, submandibular saliva 15–100 μg/ml, and parotid saliva 50–150 μg/ml. Very little of this hexosamine was lost on incubation with the bacteria of dental plaque. The glucosamine:galactosamine ratio for submandibular saliva was 1.5–4.0 and for sublingual saliva 1.5–2.7. Parotid saliva contained glucosamine almost exclusively, galactosamine being detected only occasionally and in very small quantities.

Dental plaque contained 0.3% total hexosamine on a wet weight basis which consisted of glucosamine, galactosamine and muramic acid in the approximate ratios 8:2:1. The muramic acid arises from the bacterial cell walls and the large excess of the other hexosamines indicates that they are present in the plaque matrix, not in the bacteria. It is postulated that the hexosamines of dental plaque arise from the salivary glycoproteins which consist mainly of blood-group substances.     

Fluoride, calcium and inorganic phosphorus concentrations in approximal plaque collected from young adults 1 and 24 h after toothbrushing with fluoride toothpastes.

A within-subject double-blind cross-over study was carried out to examine whether the chemical composition of approximal plaque was altered 1 and 24 h after brushing with fluoride toothpaste. Three fluoride toothpastes were tested, containing either sodium monofluorophosphate with calcium glycerophosphate supplement and calcium carbonate abrasive, a combination of sodium monofluorophosphate and sodium fluoride with the same supplement and abrasive or sodium fluoride with a silica abrasive. A fluoride-free toothpaste with a silica abrasive acted as the control. 19 subjects used the toothpastes separately in randomised order for 1 week each prior to collection of plaque. Contralateral half-mouth approximal plaque samples were collected 1 and 24 h after the last use of each toothpaste. Fluoride, calcium and inorganic phosphorus concentrations of plaque were estimated. The results indicated that brushing with toothpastes containing fluoride and/or calcium supplements resulted in increased concentrations of these constituents in approximal plaque 1 h after brushing. These elevated levels of inorganic ions were not observed in the samples collected 24 h after brushing. It was concluded that the potentially beneficial effect of a raised concentration of fluoride and calcium in approximal plaque observed soon after brushing is lost during the following 24 h.     

含钙、氟的漱口液对唾液和菌斑中氟浓度的影响

目的:测定正常人应用加入钙离子的含氟漱口液漱口后菌斑和唾液中的氟离子浓度,并探讨其防龋作用。方法:成人自愿者15名,使用0.2%NaF 2?Cl2漱口液漱口1min,分别收集漱口后1h和2h的唾液和菌斑,用氟离子选择性电极测定氟离子浓度,并与基线水平以及0.2%NaF漱口液相比较。结果:两种漱口液漱口后1h和2h,牙菌斑及唾液中氟浓度较基线水平有显著性增高(P<0.05),尤其是0.2%NaF 2?Cl2漱口液差异较明显。结论:在相同的氟离子浓度条件下,加入钙离子的含氟漱口液可以增加菌斑和唾液中的氟离子释放,延长了氟作用时间,提高防龋效果。     

Variability of calcium and phosphorus concentrations in dental plaque collected from human anterior teeth.

Samples of dental plaque were collected from single interdental spaces on the labial aspect of upper and lower anterior teeth and the calcium and phosphorus concentrations measured in each sample. The significant difference previously reported between concentrations in plaque from upper and lower anterior teeth was confirmed. Despite a trend towards higher concentrations in the midline, no significant difference was found in either calcium or phosphate concentrations in plaque from single upper interdental spaces. In the lower interdental spaces the highest concentrations of calcium and phosphate were found in plaque between central and lateral incisors whereas the lowest concentrations in plaque were between lateral incisors and canines. Only the difference in calcium concentration was statistically significant.     

Vital microorganisms in early supragingival dental plaque and in stimulated human saliva

The aim of this study was to compare the percentage of vital microorganisms (= microbial vitality) of saliva with that of supragingival plaque both collected at various times during the early phases of de novo plaque formation. Between intervals of optimal oral hygiene, 14 healthy participants refrained from all oral hygiene measures for periods of 1, 4, 8 and 72 h. Stimulated whole saliva was collected at the beginning (= baseline) and the end of each period. Vestibular plaque was removed from teeth 13–16, and 23–26. Analysis of the pooled plaque (p) and saliva (s) samples comprised the total number of bacterial counts and colony-forming units to estimate the percentage of viable microorganisms (PE_p; PE_S). The microbial vitality (VF_p; VF_S) was determined by using a fluorescence staining to differentiate vital from dead bacterial cells. The bulk of the PE_S values reached 5–30%. At baseline VF_S ranged between 70% and 90%. The VF_S values recorded at baseline or in the presence of 1 h and 4 h-old plaque, were significantly (α= 0.05) higher than the corresponding VF_p values ranging from 5% to 30%. It was concluded that there is a considerable discrepancy between the microbial vitality of a very early dental plaque and that of whole surrounding saliva sampled at the same time. Unfavourable local environmental conditions prevailing at cervical tooth surfaces are suggested to restrain the survival of the majority of the first bacteria adhering to a particular tooth area during the early phases of supragingival plaque formation.     

The kinetics of inorganic phosphate in human dental plaque and saliva.

The kinetics of inorganic phosphate (P_i), Na and K in plaque fluid and changes in the composition of the residual 24 h human dental plaque was studied following rinsing with water, 20 per cent sucrose, 0.12 M and 0.5 M phosphate. Rinsing with sucrose solution reduced plaque P_i to a greater extent than water, and the effect was demonstrable 10 min later. The main effect of both on plaque P_i was due to the exposure of plaque to a P_i-free solution. Rinsing with P_i elevated plaque fluid P_i but the effect was short-lived and not detectable 15 min later irrespective of the concentration used. Changes in the Na and K concentrations in plaque fluid after sucrose could not be related to the effects of bacterial metabolism. Phosphate added to sucrose and ingested simultaneously was cleared from the saliva at a time when substantial amounts of carbohydrate remained. The effect of sucrose in lowering plaque fluid P_i was prevented by 0.12 M P_i introduced separately after the sucrose and was reversed by 0.5 M P_i. It was concluded that the local effect of raising plaque P_i would not contribute significantly to inhibition of acid production, desorption of protein from enamel hydroxyapatite or buffering and that when P_i was introduced into plaque separately from, and after, sucrose the elevated plaque fluid P_i could exert a short-lived local effect, by mass action, on the dissolution and remineralization of enamel.     

Correlation in inorganic ion concentration between saliva and plaque fluid

The composition and the concentration of inorganic ions in dental plaque significantly influence the initiation and the development of dental caries through altering the degree of saturation of the aqueous phase surrounding the dental enamel. In order to know how plaque is affected by saliva, the composition and the concentration of inorganic ions in saliva and plaque fluid were investigated. The ionic concentrations of sodium and chlorine had similar values between plaque fluid and saliva. However, the concentrations of the inorganic ions such as ammonium, potassium, magnesium, calcium, and phosphate were significantly different between plaque fluid and saliva. This meant that the saliva and plaque fluid were different in its inorganic composition presumably reflected by the metabolic activity of bacteria in the plaque. On the other hand, as for the correlation coefficients between plaque fluid and saliva composition, statistically significant correlation was observed in ions such as sodium, ammonium, potassium, magnesium, and chlorine but not in calcium, phosphate, or in pH values. This was possibly due to the fact that saliva was the main source of supply of these ions. However as for calcium and phosphate, no close correlation was found possibly because they could be supplied also through tooth enamel dissolution. The discrepancy of the results with former studies on this point was speculatively explained by,the difference of the plaque age used. It was considered reasonable that the pH value was independent, as it is mainly decided by the activity of the bacteria in the plaque.     

Site-specificity of mineral ions in 2-day dental plaque obtained from children and young adults

The aim of this study was to determine the variation in mineral ions (Ca and P) concentrations in 2-day dental plaque taken from different areas of the deciduous and the permanent dentition that may be related to the caries status of tooth surfaces obtained from children and young adults. We also compared those minerals between the deciduous and the permanent dentition. Plaque samples were collected from eight dentition sites, including the upper-anterior-buccal (UAB) and -lingual (UAL), lower-anterior-buccal (LAB) and -lingual (LAL), upper-posterior-buccal (UPB) and -lingual (UPL), lower-posterior-buccal (LPB) and -lingual (LPL) regions. Significant differences among these eight different sites were determined from Ca and P ions concentrations, as well as the Ca/P ratio, calculated by ANOVA. Plaque associated with the LAL region closest to the main salivary ducts and that is less prone to caries, had significantly higher levels of Ca, P ions concentrations, a higher Ca/P ratio than any other dentition areas in both children and young adult subjects. Statistical differences were seen in minerals between children and young adults. Ca ion concentrations in dental plaque from young adults were significantly higher than those of children at the LAL site. Statistical analysis of the relationships between Ca and P ions showed that there were strong associations between Ca and P ions, especially in the UPB, LAL and LPL regions where there is a high exposure to saliva. We conclude that there is a site-specificity of plaque mineral content in both children and young adults, which may reflect the differences in exposure to saliva, resulting in differences in the local cariostatic challenge.     

The relationship between inorganic ion composition of saliva and dental caries prevalence in children]

In order to know the relationship between inorganic ion composition of saliva and dental caries prevalence, saliva from children was studied. The saliva samples were collected from 30 subjects aged 3 to 18 years. Each inorganic ion concentration and pH of saliva was measured and their relationship to dental caries was studied. The results were as follows: 1. Significant relationship was noted between ammonium ion concentration and caries prevalence. It was suggested that the ammonium ion was derived from decomposition of urea or amino acids. 2. Although a significant relationship was also noted between potassium ion concentration and caries prevalence, its direct process is unknown. 3. The sodium ion concentration in saliva increased with age, which implies its relationship to the development of the hormonal system.     

Partial recording of gingivitis and dental plaque in children of different ages and in young adults

In epidemiologic studies, total recordings of the amount of dental plaque and the degree of gingival inflammation tend to be too time-consuming. Various partial recording methods have accordingly been suggested. However, the validity of these methods when applied to different age groups has not been investigated sufficiently. The aim of the present study was to test whether different systems for partial recording of plaque and gingivitis can take the place of a full-mouth recording in children of different ages and in young adults. Ninety children, divided into three age groups (4-6, 7-9, 14-16 yr), and 30 adults (20-22 yr) were examined. The degree of gingival inflammation was recorded using the Gingival Index and the amount of dental plaque using the Plaque Index. Two partial recording methods were tested. One of these covered the teeth suggested by Ramfjord, modified for children with a primary dentition, and the other the front segment of the maxilla. The results were compared with those from an examination of all tooth surfaces. In all age groups excellent agreement was found between the partial recording method suggested by Ramfjord and a full-mouth recording of both the gingival state and the amount of dental plaque. Examination of the maxillary front segment was less accurate and resulted in a systematic underestimate.     

The relationship between 48-h dental plaque accumulation in young human adults and the concentrations of hypothiocyanite, 'free' and 'total' lysozyme, lactoferrin and secretory immunoglobulin A in saliva.

Samples of resting and stimulated whole saliva and stimulated parotid saliva were collected from 40 young adults. One week later, after 48 h on a standardized diet without oral hygiene, all available plaque was collected for dry weighing. An inverse relationship was found between the 'free' lysozyme concentration in stimulated parotid saliva and plaque dry weight (r = -0.46, p less than 0.01). There were no other statistically significant correlation coefficients between concentrations of individual salivary constituents and plaque dry weight. However, cluster analysis of constituents in resting whole saliva revealed three groups of subjects with different salivary profiles, and in particular with different concentrations of both IgA and hypothiocyanite. Subsequent analysis revealed differences in plaque dry weight between the groups, demonstrating the potential biological significance of cluster membership based on salivary factors.