Sugar and dental caries: a review of human studies.

Studies of special population groups, epidemiological surveys, controlled longitudinal studies of humans, and longitudinal studies on the effect of sugar substitutes indicate that frequent or high intake of sugary foods predisposes to dental decay. The relation is not always clear-cut, and most studies have important methodological problems and limitations. Longitudinal measurements of caries increments combined with multiple dietary histories are needed to clarity the association between caries and eating habits. The relative cariogenicity of specific foods can be assessed by a combination of in vitro tests, human in vivo tests, and experimental caries in animals. Human diets, however, vary in food items eaten and the frequency and sequence of eating, and these factors can affect the cariogenicity of a food. Therefore, reported correlations must be interpreted with caution.

Electroencephalographic changes and periodontal status during short-term vitamin B-6 depletion of young, nonpregnant women.

As part of a larger investigation to determine the effect of animal vs. plant proteins on the vitamin B-6 requirement of young women, clinical changes during vitamin B-6 depletion were documented. Eight healthy young women were confined to a metabolic unit and fed a defined formula diet nearly devoid of vitamin B-6 (less than 0.05 mg/d). Serial electroencephalographic (EEG) tracings, peripheral nervous system tests, periodontal evaluations, and biochemical measures of vitamin B-6 status were conducted. Within 12 d on the depletion diet, two of the eight women exhibited abnormal EEG tracings. These changes were readily reversed by repletion of vitamin B-6 at the 0.5-mg/d level. Biochemical measures reflected lowered vitamin B-6 status but were not predictive of the onset of EEG changes. No detectable alterations in oral or periodontal status were found, nor did plaque flora change markedly. This study is the first report of EEG changes occurring in women undergoing vitamin B-6 depletion and the first report to document EEG changes in adults within 12 d on a vitamin B-6-depletion regimen.

Fluoride balance studies in healthy men during bed rest with and without a fluoride supplement..

In a program of studies of disuse osteoporosis, fluoride balances were determined in healthy men during ambulation and then during bed rest for 6 to 17 wk. Control subjects ingested basal diets containing 0.4 mg fluoride per day, whereas experimental subjects received 10-mg fluoride supplements in divided doses with meals. Fluoride and calcium were measured in diets, urine, and feces. Serum analyses included calcium and ionic fluoride. Fluoride balances during both phases were uniformly negative in control subjects (mean -0.46 mg/day) but uniformly positive in supplement subjects (mean +2.58 mg/day). Calcium balances were markedly negative during bed rest in both groups. Serum fluoride concentrations increased proportionally to fluoride intake, averaging 0.016 ppm in the controls and 0.045 ppm in the supplement subjects. The supplement of 10 mg fluoride daily did not protect against bed rest-induced calcium loss, or cause any clinical or laboratory abnormality in any subject.

Fluoride balance studies in ambulatory healthy men with and without fluoride supplements.

Fluoride balances were determined in healthy adult males under metabolic ward conditions. This is the first fluoride study to use the diffusion method in exploring the balances of subjects ingesting basal (i.e., everyday) diets with deionized water for cooking and drinking. Certain groups were given daily supplements of 5 or 10 mg. fluoride as sodium fluoride in divided doses with meals. Fluoride was measured in the diets, sodium fluoride tablets, urine, feces, and serum. Approximately 90% of the fluoride excreted was found in the urine and the remainder in the feces in all groups. In the control subjects, fluoride balances were uniformly negative (mean of -0.40 mg/day); in contrast, balances were uniformly positive (mean of +1.38 and +2.88 mg/day, respectively) in subjects receiving 5 or 10 mg F supplements daily. Serum ionic fluoride concentration increased proportionally to fluoride intake and averaged 0.016, 0.029, and 0.040 ppm in the control, 5-mg and 10-mg groups, respectively. These fluoride supplements did not cause any clinical or laboratory abnormality in any subjects.

Dietary fluoride supplementation for the prevention of caries.

Fluoride supplements are effective in preventing dental caries if conscientiously taken on a daily basis from birth until at least 12 to 14 years of age. The optimal dose depends on the child's age and the existing fluoride concentration in the water supply. A dosage schedule is recommended that decreases the dose of fluoride in infancy and that is inversely related to the concentration of fluoride in the drinking water.

Topical fluoride therapy: discussion of some aspects of toxicology, safety, and efficacy.

Although ingestion of an acute toxic dose of fluoride is extremely rare in dental treatments, practitioners should be familiar with the signs and symptoms and with emergency measures of treating accidental overdosage. The amount of fluoride ingested chronically from the use of self-applied topical fluoride can be reduced to safe limits by instructing parents to dispense small amounts of toothpaste for their young children and to ensure that fluoride dentifrices and mouthrinses are fully expectorated. Similarly, when custom-fitted trays are used, only minimal amounts of fluoride gels are necessary. The minimal amount of such gels that can be dispensed appears to be influenced by their viscosity. Clinical efficacy does not support a reduction in the concentration of fluoride in commercial dentifrices.

Current regulations and recommendations concerning water fluoridation, fluoride supplements, and topical fluoride agents.

In recent years, an increase in the prevalence of dental fluorosis, mostly of the very mild to mild category, has been seen in the United States. This paper therefore discusses the safety of dental fluoride products, primarily with respect to the risk of dental fluorosis due to chronic ingestion of these products by pre-school children. No change is indicated in the optimal fluoride level (0.7 to 1.2 ppm) for water fluoridation. A reduction in the dosage of fluoride supplements is recommended for children aged from three to six years (14.5 to 22 kg body weight) residing in communities with less than 0.7 ppm F. Physicians, pharmacists, and dentists need to be better educated in correctly prescribing fluoride supplements; such prescriptions should be based on the fluoride concentration of the domestic water supply and the child's weight/height/age. No change is recommended in the concentration of fluoride used in dentifrices and mouthrinses. The US Food and Drug Administration should require more explicit labeling of fluoride products with regard to avoidance of ingestion, use of small amounts, and need for supervised use by pre-school children. The efficacy of water fluoridation, fluoride supplements, and topical fluoride agents has been amply documented elsewhere.

A theoretical study of in vivo lesion repair using a controlled-release device.

A theoretical model of lesion remineralization predicts that in vivo caries repair can be effected in a five-day period by means of a controlled- and sustained-release device containing calcium, phosphate, and fluoride. The calculations detail an 80% repair before the remineralization process stops. However, the fluoridated hydroxyapatite formed is calculated to be about 20% more resistant to future attack than is hydroxyapatite, making effective repair complete. Optimal flux (W) conditions for repair of 100 microns lesions are WCa = 1.0 X 10(-6) kg/m2s, stoichiometric phosphate, and WF = 2.0 X 10(-9) kg/m2s.

The effect of mouthrinse containing calcium glycerophosphate on the chemical composition and development of plaque in humans.

Children rinsed twice daily with one of two concentrations of calcium glycerophosphate or a placebo. Plaque was collected at two-week intervals for eight weeks, and Löe and Silness Indices determined. Results indicate a lower index rating and a higher phosphorus content for experimental groups than for the control at the four-week examination.

Susceptibility of some plaque microorganisms to chemotherapeutic agents.

Investigators have used chemotherapeutic agents topically for plaque control without knowing the drug concentration necessary to inhibit the growth of odontopathic microorganisms. S mutans, S sanguis, A viscosus and A naeslundii are important components of the plaque flora. The minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) of niddamycin, vancomycin, bacitracin, and kanamycin were determined for each organism in liquid culture. These antibiotics were selected because of their low absorption from the gastrointestinal tract. Niddamycin, vancomycin, and bacitracin had the lowest MIC, from 0.2 to 10 units/ml. Kanamycin was inhibitory only at much higher concentrations (130 to 500 units/ml). The corresponding MBC was generally higher than the MIC. A viscosus was the most resistant organism tested. These data are important in designing controlled release devices for delivering a suitable antibiotic on a continuous basis intraorally.

Staining reaction of dental plaque after various extraction procedures.

After water and dilute alkali extraction, a sample of dental plaque that was stained by the PA-CrA-silver technique showed staining intracellularly on the cell wall and extracellularly. When more prolonged and stronger alkali extraction was used, reacting material was retained on the cell wall and intracellualarly. There was a noticeable loss of extracellular reacting material.

The effect of previous diet on plaque pH response to different foods.

In this study we investigated the effect of previous diet on the response of plaque pH to three test foods. The study population consisted of 11 dental students. Plaque pH was measured, by means of the touch electrode method, on the first two upper molars. The study was conducted at two sessions, one week apart. Subjects followed a 48-hour high-sugar diet before the first test session and a 48-hour low-sugar diet before the second test session. During both 48-hour periods, students refrained from all oral hygiene practices and fluoride utilization. At each session, three foods were ingested at one-hour intervals: cola, beer, and chocolate bar. pH measurements at baseline and at selected times after food ingestion were recorded and analyzed. Multivariate analysis of variance revealed significant independent effects of food, previous diet, and their interaction on plaque pH. After the same foods were ingested, plaque pH response after a previous high-sugar diet was significantly more acidic than after a previous low-sugar diet.

Levans: I. Fractionation, solution viscosity, and chemical analysis of levan produced by Streptococcus salivarius.

Levan produced by Streptococcus salivarius was fractionated into a series of 20 fractions of varying molecular weight. The range of intrinsic viscosities of the fractions was 0.07 to 0.18 dl/gm in water and 0.20 to 0.29 dl/gm in dimethyl sulfoxide. The molecular weight of the unfractionated leval determined by light scattering was 31.5 times 10-6. Small amounts of fatty acids and protein were found associated with levan.

Effect of dichloromethylene diphosphonate on fluoride balance in healthy men.

Healthy men with a daily intake of 0.37 mg fluoride were given dichloromethylene diphosphonate (Cl2MDP) or a placebo during a period of ambulation followed by bed rest. In both groups, serum ionic fluoride was unchanged, and fluoride balances were negative, but Cl2MDP significantly reduced loss of fluoride in the treated groups.

Indices to measure gingival bleeding.

Gingival bleeding is an objective, easily assessed sign of inflammation that is associated with several periodontal diseases. Many bleeding indices have been devised; some assess bleeding as simply present or absent, whereas others use grading in an attempt to assess severity of bleeding. The choice of which index to use depends on whether the purpose is an epidemiological survey, a clinical study, diagnosis and treatment, or patient motivation. Bleeding may be elicited manually with toothpicks, dental floss or a periodontal probe, but a controlled-force probe, although more expensive, causes less trauma and less false-positive bleeding from healthy tissues. As a predictor of periodontal disease progression, bleeding on probing has low sensitivity owing to a high frequency of false-positive responses, but has high specificity in that failure to bleed indicates health. There is evidence that smokers have less, or delayed, gingival bleeding when compared with non-smokers; therefore smoking needs to be controlled for in studies of gingival bleeding. Measurement of gingival bleeding tendency should be an integral part of a comprehensive oral examination. In clinical practice, the use of a graded bleeding index is more likely to identify sites that are at risk of further destructive activity. For monitoring individual patients, both for response to initial therapy and during maintenance, a modified Sulcus Bleeding Index (mSBI) with three bleeding scores is recommended in preference to dichotomous scoring of bleeding.

Bactericidal action of bicarbonate ion on selected periodontal pathogenic microorganisms.

Organisms representative of soil, skin and fecal flora and of supragingival and subgingival flora were tested for inhibition of growth and killing by various salts (NaHCO3, NaCl, MgSO4). The antimicrobial activities of KHCO3, NaF, sodium lauryl sulfate (SLS) and chloramine T were also compared with that of NaHCO3, and the rate at which NaHCO3 exerts its bactericidal effect was studied. Suspected periodontal pathogens were more susceptible to salts than were control non-oral bacteria. Supragingival plaque organisms showed intermediate susceptibility. Periodontal pathogens were more susceptible to NaHCO3 than to NaCl; NaHCO3 and KHCO3 showed similar activity against all strains tested. Accordingly, the antibacterial activity of NaHCO3 is not simply an osmotic effect and is due to the bicarbonate ion. NaF, SLS and chloramine T had greater antimicrobial activity than NaHCO3. Supragingival bacteria required at least 6-hour exposure to 1.0 M NaHCO3 to produce 99% lethality (decrease colony-forming units by 2 log10), whereas selected periodontal pathogens were killed more rapidly (30-120 minutes). The higher the concentration of bicarbonate, the faster the lethality. Morphologic examination by transmission electron microscopy of organisms exposed to bactericidal salt concentrations revealed marked fibrillar condensations within the cytoplasm and shrinkage of the cytoplasm from the outer membrane. For NaHCO3 to be clinically effective, a high concentration must be introduced into the periodontal pocket and maintained there long enough to kill periodontal pathogens. Furthermore, NaHCO3 must be reapplied often enough to prevent recolonization by these pathogens. An advantage of NaHCO3 over NaF, SLS and other antimicrobial agents is its safety, availability and low cost.

Diffusion of small ionic species in human saliva, plaque fluid and plaque residue in vitro.

The tracer diffusion of small ionic species was investigated in water, saliva, dental plaque fluid and in plaque residue packed by a range of g forces. Diffusion rate of NaCl was similar in water, saliva and plaque fluid. The rate of CaCl2, NaH2PO4, Na2HPO4 and Na2SO4 was less in both saliva and plaque fluid. Diffusion rate of all ionic species tested was significantly less in plaque residue, most of all for CaCl2. In plaque fluid, plaque residue and water, an inverse linear relationship was found between log diffusion coefficients and log molecular weights. Increasing the tortuosity of the diffusion path, by packing plaque residue, further reduced the diffusion rate of NaH2PO4 and NaHCO3. In terms of three-dimensional diffusion, in plaque fluid, NaH2PO4, Na2HPO4 and CaCl2 diffused a distance of 300 microns within 25 s, whereas in plaque residue the equivalent diffusion times were 1.5-5.7 min. The unique retardation of CaCl2 in plaque residue implicated both non-specific and specific binding interactions.

Inhibition by acarbose, nojirimycin and 1-deoxynojirimycin of glucosyltransferase produced by oral streptococci.

Acarbose is known to inhibit glucoamylase, maltase and sucrase. Our aim was to test whether it would also inhibit glucosyltransferase (GTF), to determine the type of inhibition and to compare the inhibitor potency of acarbose with that of nojirimycin and deoxynojirimycin, two other glucosidase inhibitors. Enzyme inhibition was measured either by chemical assay or by incorporation of radioactivity into product. Acarbose effectively inhibited the synthesis of polysaccharide by GTF from strains of Streptococcus mutans and Streptococcus sanguis, but not by fructosyltransferase from Streptococcus salivarius. Acarbose and 1-deoxynojirimycin were more potent inhibitors of GTF than maltose, nojirimycin or various amino sugars. The mechanism of action of these compounds is consistent with competitive inhibition.

Characterization of a trypsin-like protease from the bacterium Bacteroides gingivalis isolated from human dental plaque.

A trypsin-like, membrane-bound protease from Bacteroides gingivalis was solubilized by Triton X-100 and partially purified by a combination of DEAE-Sepharose and aminophenylmercuric Sepharose chromatography, by taking advantage of the thiol group on the enzyme. The purified enzyme hydrolysed the synthetic substrates benzoyl-L-arginine-p-nitroanilide (L-BAPA), benzoyl-D,L-arginine-beta-naphthylamide (BANA) and tosyl-L-arginine methyl ester, as well as bovine serum albumin and ovalbumin, but not tosyl-L-lysine methyl ester. The enzyme activity was enhanced by SH-reagents and was inhibited to different degrees by SH-inhibitors, chelators and microbial low-molecular-weight inhibitors such as leupeptin, antipain and chymostatin. These microbial inhibitors could be of practical use as ligands for affinity chromatography for further purification. The possible involvement of the protease in periodontal diseases is also discussed.

Comparison of trends in the prevalence of caries and restorations in young adult populations of several countries.

We compared DMFT (decayed, missing and filled teeth) values of young adult populations (about 18- to 21 yr old) obtained over two decades in five industrialized countries (Denmark, Finland, Israel, Japan, U.S.A.). Trends of the active disease factor (D) and treatment factor (F) within and between these countries during two decades were also compared. No uniform trend in caries prevalence data, based on total DMFT scores, was found. In some countries DMFT scores declined (Denmark, U.S.A.), in some they remained relatively static (Finland), and in some they increased during the last 20 yr (Israel, Japan). However, DMFT scores did not always correlate with untreated lesions, D, which decreased remarkably in Denmark and Finland and moderately in the U.S.A., remained stable in Japan, but increased in Israel. Similarly, treatment of caries, F, varied in different countries, increasing dramatically in Finland and Japan and moderately in Israel, remaining static in Denmark, and decreasing in the U.S.A. These trends appear to be influenced largely by the extent of caries-preventive measures (particularly fluorides) in the respective countries, and to a lesser degree by sugar utilization and the availability of dental personnel. This age population has not been studied in a comparative fashion previously. This study also emphasizes the importance of looking not only at DMFT scores but at the trends in meeting treatment needs, D vs F scores.