Methamphetamine abuse: medical and dental considerations

Amphetamines are central nervous system stimulants with high abuse potential and intense physiological and psychological effects. Abuse of methamphetamine--a methyl derivative of amphetamine--has grown to epidemic proportions across the United States. Due to the characteristic signs of methamphetamine abuse that appear in the oral cavity dentists should have a heightened awareness of the medical and dental issues surrounding this dangerous behavior. Moreover, recognition and proper referral to treatment should be a part of every provider's plan for preventing the devastating psychological, oral, and overall systemic effects of methamphetamine abuse.

Bonding of resin to artificially carious dentin

PURPOSE

To evaluate the bond strength of adhesive resins to artificially carious dentin specimens which were previously exposed to an acid buffer solution for various periods.

MATERIALS AND METHODS

Flat dentin disks were obtained from superficial occlusal dentin of extracted human third molars and polished with wet silicon carbide paper. Dentin disks were immersed in acid buffer solution for different periods to create the demineralized dentin layer. The first group of demineralized specimens was used for the evaluation of demineralization depth under SEM and the second group was used for the bond strength measurement. Shear bond strengths mediated by three dentin adhesives (Clearfil SE Bond, OptiBond Solo Plus Total-Etch, and OptiBond Solo Plus Self-Etch) were examined. A 0.75-mm-diameter area of dentin was bonded according to the manufacturers' instructions before placing a 0.5-mm-high resin composite cylinder. The bonds were stressed in shear at a crosshead speed of 1 mm/min. All data were analyzed using ANOVA and LSD multiple comparison test.

RESULTS

Depth of demineralization increased with the prolongation of demineralizing time. After dentin specimens were demineralized for up to 24 h, bond strengths of the self-etching adhesives were significantly higher than those of the total-etch adhesive. However, for longer demineralization periods, no statistical differences in bond strengths were observed. SEM photographs showed that resins cannot thoroughly infiltrate through the whole depth of the demineralized dentin layer.

CONCLUSION

Bond strengths to demineralized, artificially carious dentin were affected by the depth of demineralization and adhesive resins used.

[Lead level, enamel defects and dental caries in deciduous teeth]

OBJECTIVE

To verify the relationship between lead concentration in the enamel of deciduous teeth and the presence of enamel defects and, consequently, with dental caries among preschool children.

METHODS

The sample consisted of 329 preschool children in Piracicaba, State of São Paulo: 132 attending municipal kindergartens close to industrial plants and 197 attending kindergartens in non-industrial areas. This sample belonged to an initial study made between 2000 and 2001, in which the lead concentration was obtained by means of enamel biopsy. Oral clinical examination of the children from both regions was performed to verify the prevalence of enamel defects, using the Developmental Defects of Enamel (DDE) Index of the World Dental Federation (FDI), and of dental caries, using the decayed, missing and filled surfaces (dmfs) index of the World Health Organization. The chi-squared test and relative risk calculation were utilized in relation to a significance level of 5%, considering each region separately.

RESULTS

Among the children from the non-industrial area, there was a higher proportion with dental caries among those with higher lead concentrations in deciduous teeth (p=0.02). This was not, however, observed among the children from the industrial area (p=0.89). There was an increased relative risk (RR) of caries among the children from the non-industrial area, but this was not seen among the children from the industrial area. No relationship was observed between the presence of lead and enamel defects.

CONCLUSIONS

No data was found that would give evidence of a relationship between lead concentration and enamel defects in either of the areas studied. No relationship was found between lead and dental caries in the industrial area, thus emphasizing that more studies of such relationships are needed.

[Clinical aspects of the evolution of dental caries and periodontal disease in patients treated with corticosteroids]

Patients treated with adrenal glucocorticoids may run a higher risk of dental caries, both as a result of their medical condition and of the physical and physiological effects of their pharmacotherapy. Our clinical study reports about patients treated with glucocorticoids who were also having an odonto-periodontal condition. They were examined and we found rampant caries and periodontal diseases. The slow evolution of asymptomatic periodontal disease encouraged destruction of teeth in root caries. The rampant caries were correlated with immunodeficiency and treatment of these caries must take into account the general treatment.

Fluoride releasing materials: their anti-cariogenic properties tested in in vitro caries models

The anti-cariogenic properties of three fluoride-releasing materials on root surfaces were evaluated using two different caries models. Standardized cavities were prepared in dentin specimens and restored with either glass-ionomer, resin-modified glass-ionomer, polyacid-modified resin composite or resin composite material. Two groups of 56 specimens were demineralized using a microbial caries model for three days, while another 56 specimens were demineralized using a chemical demineralization model for three days. Lesions around the restorations were measured with a confocal laser scanning microscope. Glass ionomers demonstrated significant anti-cariogenic properties when exposed to the chemical model. However, no significant anti-cariogenic properties were observed with the microbial caries model. In conclusion, the fluoride releasing materials showed different anti-cariogenic properties in root surfaces under the different caries models, suggesting that caution should be exercised when trying to extrapolate the results of in vitro studies to the clinical situation.

Relationship between S. mutans and the autofluorescence of carious dentin

PURPOSE

To investigate the relationship between the presence of S. mutans and the autofluorescent signal detected in carious dentin, using confocal laser-scanning microscopy.

METHODS

Experiment 1:15 visually caries-free freshly extracted premolars were coated with varnish except for two 2 mm x 2 mm windows; five were subjected to a 15-day bacterial artificial caries system using Streptococcus mutans while 10 underwent a 7-day controlled, lactic acid (0.5 M, pH 2.7) demineralization protocol. At the end of both periods, all teeth were longitudinally sectioned and the 20 bacterial and 40 acid-induced artificial lesions were examined by confocal laser-scanning microscopy. The media containing the S. mutans was also examined for autofluorescence. Experiment 2: 20 750 microm-thick caries-free coronal dentin disks were prepared from 10 healthy premolars. Ten underwent a demineralization protocol using 0.1 M EDTA (pH 4.8) for 21 days. All 20 were finally subjected to the same artificial bacterial caries system as above for 15 days and then examined for autofluorescence using confocal laser-scanning microscopy.

RESULTS

Experiment 1 results showed that acid-demineralized lesions did not generate any autofluorescence. Lesions created by the bacterial system did exhibit autofluorescence. The media with or without S. mutans did not exhibit autofluorescence. Experiment 2: bacteria-induced lesions on dentin that had previously been acid-demineralized generated a visibly stronger autofluorescence signal than those lesions grown on sound dentin. It is hypothesized that dentin demineralization during the carious process exposes more matrix to a bacteria-matrix interaction, thus generating or refining the matrix chromophore responsible for the autofluorescence signal detected in carious dentin.

Sugars and dental caries

A dynamic relation exists between sugars and oral health. Diet affects the integrity of the teeth; quantity, pH, and composition of the saliva; and plaque pH. Sugars and other fermentable carbohydrates, after being hydrolyzed by salivary amylase, provide substrate for the actions of oral bacteria, which in turn lower plaque and salivary pH. The resultant action is the beginning of tooth demineralization. Consumed sugars are naturally occurring or are added. Many factors in addition to sugars affect the caries process, including the form of food or fluid, the duration of exposure, nutrient composition, sequence of eating, salivary flow, presence of buffers, and oral hygiene. Studies have confirmed the direct relation between intake of dietary sugars and dental caries across the life span. Since the introduction of fluoride, the incidence of caries worldwide has decreased, despite increases in sugars consumption. Other dietary factors (eg, the presence of buffers in dairy products; the use of sugarless chewing gum, particularly gum containing xylitol; and the consumption of sugars as part of meals rather than between meals) may reduce the risk of caries. The primary public health measures for reducing caries risk, from a nutrition perspective, are the consumption of a balanced diet and adherence to dietary guidelines and the dietary reference intakes; from a dental perspective, the primary public health measures are the use of topical fluorides and consumption of fluoridated water.

[Structural disorder of dental enamel caused by antineoplastic agents--case report]

Cancer is the second most common cause of mortality in childhood. Complex therapy decreases the rate of mortality, but chemotherapy and irradiation may, however, create acute and long-term side effects. Although immuno- and myelo-suppressive side effects of anti-neoplastic therapy are unavoidable, their detrimental impact on oral health can and should be avoided contributing to a better quality of life of these children.

Medications: impact on dental diagnosis and treatment planning

Today, many patients regularly take prescription and over-the-counter medications that may be a risk factor for periodontal disease and caries. The sugar in many medications presents a serious caries challenge, which, in some cases, is compounded by an acidic pH. Attitude-altering medications may inhibit compliance with oral hygiene. Many medications cause xerostomia, which can lead to root surface caries and candidiasis. In many cases, these drugs cannot be substituted and dosages cannot be reduced, so it is essential to detect adverse conditions early and begin oral hygiene treatment planning to prevent more severe dental conditions from developing. This article discusses the impact of medications on treatment planning for patients who have clinical manifestations of dental problems that are attributed to medications.

[Dental changes in patients treated with calcium antagonists]

For a period of 7 years the dental status of 160 patients has been investigated and followed. These patients have been treated with calcium channel blockers and selected in age between 22 and 50 years. Their diagnoses are: m. hypertonicus I-II stage--106, WPW-syndrome--10, stenocardia--18, atrial extrasystolia--26. Duration of treatment--from 1 to 7 years (corinfar, nifedipin, adalat--tabl. 40 mg, taken peroral or chewed, respectively suck; isoptin, verapamil--tabl. 40 mg, diltiazem--tabl. 30 mg, taken peroral. A control group of 60 clinically well people at age from 20 to 48 years was investigated. Under continuous treatment with calcium antagonist (> 1 year) the examined patients are found to have considerable decalcination of the dental enamel and caries more frequent (87.5%) compared to the group of clinically healthy people (65%), also increased number of caries in the same patient in comparison to his dental status before starting the therapy in 108 of 160 (67.5%). The differences in the results are statistically significant (p < 0.001). The number of the discovered caries in patients treated with calcium channel blockers and in the studied groups is also large (4 to 2 on average, i.e. two times more). The results allow to recommend a continuous stomatological control for patients treated with calcium antagonists.

Efficacy of sterilisation methods and their effect on enamel demineralisation

The aim of this project was to determine the effectiveness of sterilisation methods for dental enamel for use in intra-oral cariogenicity tests, and their possible effect on the degree of demineralisation of enamel. Bovine incisors were cut vertically into five portions and each assigned to one of five groups. Group 1 was used as a control while the other four groups were subjected, respectively, to gamma irradiation ( congruent with 25kGy), steam autoclaving (121 degrees C for 15 min), sodium hypochlorite (12% w/v for 24h) and povidone-iodine (7.5% w/v for 24h). Total viable counts of microorganisms remaining following sterilisation of the specimens were performed following incubation of the specimens for 24h at 37 degrees C. Caries-like lesions were produced in each specimen using an acidic buffer solution (pH4.5). Sections were cut from each specimen, ground to 80-microgram thickness, and microradiographed. Mineral loss and lesion depth were quantified using transverse microradiography. Statistical analysis was by ANOVA. Dunnett's and Tukey's tests. Microbial growth (Staphylococcus aureus and bacilli) was observed only in control specimens in both brain heart infusion broth and on blood agar plates. The sterilisation methods affected the enamel surface as follows: gamma irradiation (cream discolouration), NaOCl (bleaching), and povidone-iodine (white spot-like lesion). Compared with the control, there was no significant difference in mineral loss and lesion depth with any of the groups, but the numerical values of mineral loss and lesion depth in groups can be ranked as follows: gamma irradiation <povidone-iodine <control <autoclave <NaOCl. In conclusion, the four sterilisation methods were all effective to sterilise enamel, but gamma irradiation proved the most acceptable method for enamel to be used in cariogenicity tests having the least adverse effect.

The effect of chronic clonidine administration on salivary glands and caries in the rat

Clonidine is a widely prescribed, centrally acting antihypertensive with proposed pharmacologic mechanisms of stimulation of central postsynaptic alpha(2)-adrenergic receptors and agonist activity at presynaptic alpha(2)-adrenergic receptors, interfering with peripheral regulation of norepinephrine and acetylcholine release. Both of these mechanisms are capable of adversely influencing salivary output and composition, potentially leaving an individual with increased caries risk. The purpose of the present study was to determine the effect of chronic administration of clonidine on saliva, salivary glands, and caries in rats. Sprague-Dawley rat pups were infected with Streptococcus sobrinus, given Diet 2000 and 10% sucrose water ad libitum, and either desalivated, or treated with clonidine HCl (125 or 250 microg/kg administered daily for 28 days by means of osmotic minipumps), or assigned as controls. There were no statistical differences in stimulated parotid or submandibular gland salivary output or sublingual gland weights among the groups. The weight of the submandibular glands as a percent of total body weight was significantly decreased in animals that received clonidine when compared with controls. Sulcal caries scores in both clonidine groups and smooth surface caries scores in the high clonidine group were increased when compared with control animals. Positive control animals (desalivated) had significantly higher caries scores than all other groups. These data show that chronic administration of clonidine significantly decreases submandibular gland weight and increases susceptibility to dental caries.

Reproducibility of quantitative measurement of white enamel demineralisation by image analysis

The reproducibility of measuring artificial enamel white spot lesions from captured photographic images using computerised image analysis was assessed. Enamel lesions were induced on the buccal surface of 22 human teeth over periods of 3, 7 and 14 days. Standardised photographs were taken from above and below the occlusal plane. These were repeated after 2 weeks. The photographs were converted into TIFF images and mean grey scale levels of the areas of etched enamel were measured using computerised image analysis. Assessment of repeat readings of the same slide showed good reproducibility for photographs taken below the occlusal plane. The limits of agreement showed reasonable agreement between readings carried out on two slides of the same tooth. Capturing TIFF images via 35-mm film and measuring grey scale levels by computerised image analysis is a useful method of quantitative study of early enamel demineralisation. This may be developed for application in the clinical setting.

Effects of caffeine and theophylline on the development of dental caries in rats

The purpose of this study was to evaluate the influence of caffeine and theophylline on the development of dental caries in rats. Six Wistar dams (spf), mutans streptococci free, were obtained, each with six male pups. The dams were infected by Streptococcus sobrinus 6715 and divided into three groups which received during the lactating period: (1) diet 2000; (2) diet 2000 plus caffeine (2 mg/100 g) and (3) diet 2000 plus theophylline (0.57 mg/100 g). After weaning, the pups were infected by S. sobrinus, placed in a König-Höfer programmed feeder machine, and received 17 meals daily at hourly intervals, for five weeks. During this time the pups were fed with the same diet that their dams were. The percentage of S. sobrinus relative to total flora was significantly higher in the theophylline group. The results for slight (Ds) and moderate (Dm) dentine lesions, for smooth-surface and sulcal scores were statistically higher for the theophylline group than the other groups. Salivary assays did not demonstrate significant inorganic alterations in salivary composition. Caffeine and theophylline groups showed the highest ulcer score. It is concluded that caffeine does not affect the cariogenic potential of the diet, however theophylline can increase the development of dental caries, and this effect may be related to organic alterations of salivary composition.

Histological features of artificial secondary caries adjacent to amalgam restorations

Artificially induced carious lesions on either side of in vitro un/restored amalgam cavities were examined to establish the degree of randomness of caries development. Class I cavities were cut in 132 extracted premolars: twelve teeth were not restored, and 120 teeth were restored with one of 20 different restoration combinations of silver amalgam, base and varnish. After ageing for periods of 3 months and 1 year, the 12 unrestored teeth and 80 of the restored teeth were subjected to an in vitro bacterial challenge for 36 days, while the other 40 specimens were challenged in acidified broth (pH 4.0). Sections were then prepared for polarized light microscopy. Carious lesion configuration on either side of the cavity was noted, and outer, wall and dentine lesions measured. Data underwent Fisher's exact test, a chi-squared goodness of fit test and a Student's paired t-test with P<0.05. Except for dentine lesions, acid broth and unrestored specimens showed carious lesions having similar size and occurrence on either side of the cavity. Two unrestored cavities showed caries resistance. Restored, bacterially challenged specimens were significantly different regarding total and wall lesion distribution and wall lesion width and area on either side of the cut cavity. Acid broth challenge will promote regular caries development at the tooth-restoration interface. The random caries pattern which developed in restored bacterially challenged specimens indicates that the tooth-restoration interface forms a diverse environment providing sites of varying susceptibility to caries.

Risks for oral health with the use of antidepressants

In this article, attention is focused on oral pathology, particularly dental caries, caused by hyposalivation as a consequence of (long-term) use of antidepressants. Changes in clinical psychiatric practice and increasing numbers of prescriptions of antidepressants in primary care and specialty care settings have made awareness of this risk even more relevant than in the past. Normal physiology of salivary glands and changes in the secretion of saliva during use of antidepressants are described. Monitoring, prevention, and treatment of hyposalivation induced by antidepressants are encouraged as an adjunct in the clinical management of depression.

Medications as a risk factor for caries and periodontal disease

Since our population is aging, patients will present to our offices with more medications than in the past. Although these medications may benefit their general health, they may adversely affect their dental health. Although most medications discussed increase the risk for caries and periodontal disease, a few may actually decrease the risk.

Influence of maternal lead ingestion on caries in rat pups

Lead is one of the most toxic and pervasive pollutants in society, and although there has been some lowering of blood lead levels in recent years, the levels continue to be of concern for African Americans, central city residents, residents in the Northeast region of the United States, persons with low income, and those with low educational attainment. Notably, these are the persons and the region where the highest prevalence of dental caries is observed. Information relating lead toxicity to oral health is sparse, but the preponderance of epidemiological data shows a relation between lead in the environment and the prevalence of dental caries. Using our well-defined rat caries model we found that pre- and perinatal exposure to lead results in an almost 40% increase in the prevalence of caries and a decrease in stimulated parotid function of nearly 30%. Levels of lead in milk from lead-treated dams were approximately 10 times as high as the corresponding blood lead levels, suggesting that lead is being concentrated by mammary glands. These findings may help in part to explain the comparatively high levels of dental caries observed in the inner cities of the United States where exposure to lead is common. Environmental sources of lead include drinking water, lead-based paint and, to a lesser extent, automobile and industrial emissions. In humans lead is accumulated and stored in bones (half-life of approximately 62 years), and even maternal exposure to lead decades before pregnancy can subsequently result in exposure of the developing fetus to elevated levels of lead. Moreover, lead concentration in maternal blood has been shown to increase during pregnancy and lactation because of mobilization of stored lead from bone, and typically, lead is found in milk at a higher concentration than the level found in maternal plasma at the same time point.

Caries-inducing activity of the hydrogenated derivative of an isomaltooligosaccharide mixture in rats

The caries-inducing activity of the hydrogenated derivative of an isomaltooligosaccharide mixture (IMO-H) was evaluated in vitro for its acidogenicity and in vivo an experimental caries system with specific-pathogen-free (SPF) rats. Streptococcus sobrinus 6715 (serotype g) did not produce a significant amount of acid from IMO-H, whereas Streptococcus mutans MT8148 (serotype c) gradually produced a small amount of acid, although the degree was less than that of sucrose. In vivo experiments were conducted on rats which were provided with the test sugars at two different times: at the time of organism inoculation, and after the organisms had become completely established. IMO-H did not induce significant dental caries in rats infected with the S. sobrinus 6715 or S. mutans MT8148R strain.

In vitro cariogenicity of trans-galactosyl-oligosaccharides

Trans-galactosyl-oligosaccharides (TOS) are a class of oligosaccharides produced by transgalactosylation of lactose. TOS are used as bifidogenic factors in human and animal nutrition. TOS can be present in the oral cavity and form a risk of caries. All oral bacteria tested were able to degrade and ferment both TOS and galactosyllactose (GLL), one of its components. Growth was improved compared with carbohydrate-free media and acid was produced after 24 h incubation of the bacteria with TOS and GLL. Degradation patterns, using HPAEC, showed degradation of most components. GLL was degraded only partially. Rapid acidification was only observed for Streptococcus mutans, resulting in a pH of 5.4 within 30 min. All other strains fermented TOS and GLL only slowly. Plaque formation could not be detected on both substrates. It can be concluded that TOS and GLL present only a small risk of caries formation, unless proven otherwise in animal studies.

Fluoride and pilocarpine reduce the risk of caries produced by chronic clomipramine treatment in rats

The effects of chronic clomipramine treatment on the incidence of caries in the rat and their prevention by fluoride and pilocarpine were investigated. One hundred and twenty male Wistar rats were divided into six groups, five experimental groups, one control group and treated with 50 mg/kg/day of clomipramine, 10 ppm fluoride in drinking water, and 5 mg/kg/day of pilocarpine. All animals were infected with Streptococcus sobrinus 6715 and fed a cariogenic diet ad libitum for 42 days. Water and food consumption, weight gain, salivary flow rate, amylase activity, protein and fluoride concentration in saliva, and caries scores were determined in all animals. Whereas clomipramine significantly increased the fluoride and protein concentration in saliva, pilocarpine only decreased fluoride concentration. Animals treated with clomipramine developed 40% more sulcal caries than nontreated animals. Administration of fluoride (10 ppm) in drinking water and chronic oral administration of pilocarpine prevented the increased risk of developing caries associated with chronic treatment with clomipramine.

Effects of carbamide peroxide whitening agents on enamel surfaces and caries-like lesion formation: an SEM and polarized light microscopic in vitro study

Whitening enamel with carbamide peroxide (CP) to remove cosmetically displeasing stains has become common-place in dental practice. This in vitro study evaluated CP treatment effects on enamel surface morphology and caries-like lesion susceptibility. Tooth quarters were prepared from 10 caries-free human molars following a fluoride-free prophylaxis. The tooth quarters were assigned to the following treatment groups: 1) Distobuccal-10 percent NW gel (Nite White, Discus Dental); 2) Distolingual-10 percent PL paste (Platinum, Colgate); 3) Mesiobuccal-16 percent NW gel; and 4) Mesiolingual-Control. Following the manufacturers' recommended treatment, each quarter was sectioned with one portion prepared for SEM and the other portion for caries-like lesion formation. Intact enamel surfaces were present with all treatments. Enamel prism markings with exaggerated prism peripheries and mild to moderate prism core loss were seen with both 10 percent NW and 16 percent NW gels, but was more prominent with 16 percent NW gel. Amorphous surface layers with occasional exposure of indistinct prism markings occurred with 10 percent PL paste. Body of lesion mean depths were 135 microns control, 159 microns 16 percent NW, 144 microns 10 percent NW, and 122 microns 10 percent PL. Lesion depths were significantly different (p < 0.05 DMR paired design) between 10 percent PL and 16 percent NW, and between control and 16 percent NW. Whitening enamel surfaces in vitro with 10 percent carbamide peroxide paste containing dicalcium phosphate dihydrate (Colgate-Platinum) produced an amorphous surface layer and reduced caries susceptibility when compared with 16 percent carbamide peroxide gel (Nite White).

Human fluorosis in Morocco: analytical and clinical investigations

A clinical investigation of human chronic fluorosis, known as "Darmous" in Morocco, was carried out in Youssoufia city and its region. Fluoride concentrations were also measured in soil and water from this area and in urine collected from the surveyed persons; soil and to a lesser extent water were rich in fluoride (948.6 +/- 356.2 micrograms/g and 1.03 +/- 0.19 micrograms/ml, respectively). Fluoride concentrations in urine were heterogenous and varied from 0.17 to 47.5 micrograms/ml. There was a good correlation between these values and the age of the sampled persons. This study revealed that 14% of the urine samples were at or above the maximum fluoride concentration in urine from non-intoxicated individuals (ie 10 micrograms/ml). Dental caries, teeth loss and teeth pigmentation and deviation were the most frequent dental effects in this area. Skeletal effects were mostly joint pain and exostosis. With the exception of dental caries, teeth and bone abnormalities were more frequent and pronounced in people living in the rural area.

Dental caries, gingival health, and oral hygiene of long term survivors of paediatric malignant diseases

Fifty two children who had had cancer and been treated with chemotherapy, and who were long term event free, were examined for caries prevalence, gingival health, and oral hygiene and compared with a control group. A higher dental caries prevalence for the 14-17 year age group was noted. The restorative index was significantly lower in the age group 10-13. There were no significant differences in gingival index, plaque index, or toothbrushing frequency. It is concluded that these patients should be considered as at high risk for caries after cancer treatment. Professional dental follow up should be integrated in the medical follow up.

Dental caries and dental anomalies in children treated by chemotherapy for malignant disease: a study in the north of England

Fifty-two children in remission from childhood cancer and 41 siblings underwent a full clinical and radiographic dental examination. All the children had received chemotherapy. The leukaemic patients had received radiotherapy also, but not involving the jaws. There was no significant difference in dental caries experience between the treated children and the siblings, but significantly more dental anomalies were detected radiographically in the treated group.

The effect of EHDP concentration on enamel demineralization in vitro

The depth of caries lesions produced in bovine enamel situated in an unstirred 0.1 mol/L lactic acid buffer at pH 4.5 has been studied as a function of time and of concentration of the inhibitor ethane-1-hydroxy-1, 1-diphosphonate, EHDP. At concentrations of EHDP up to 5 mmol/L, the lesion progress decreased with increasing concentration of inhibitor. At higher concentrations, the opposite effect was observed. At low inhibitor concentration (0.1 mmol/L), the lesion depth to the third power varied linearly with time. At intermediate concentrations (0.25-5 mmol/L), the square of the lesion depth varied linearly with time. At high inhibitor concentrations (25-100 mmol/L), the lesion depth varied linearly with time. It was also shown that the rate of dissolution of calcium hydroxyapatite crystals was retarded by low concentrations of EHDP, but accelerated by high concentrations of EHDP. The results are related to a physico-chemical model describing lesion formation.

In vitro remineralization of caries lesions treated with surface-active phosphates

Intact human enamel was demineralized in vitro to obtain artificial caries lesions. Part of the lesions was then treated with different surface-active compounds and remineralized with a remineralizing solution. The other part of the lesions was de- and remineralized in the same way, but was not treated with a surface-active compound. The results indicate that none of the surface-active compounds do affect the remineralization of the caries lesions. Possible applications of the tested compounds in combination with fluoride, for the prevention of dental caries, are discussed.

Remineralization of bovine incisor root lesions in vitro: the role of the collagenous matrix

This study deals with the role of collagen in the remineralization of bovine incisor root lesions. The degradability of the collagenous matrix after in vitro remineralization was also investigated. The root surfaces were exposed to 0.1 M acetic acid, pH 4.0, to produce erosive lesions or to 0.1 M lactic acid, 0.2 mM methane hydroxy diphosphonate, pH 5.0, to produce subsurface lesions. After demineralization, the roots were subjected to remineralization, with or without prior treatment with a bacterial collagenase to remove accessible collagen. Remineralization was carried out in solutions with a Ca/Pi molar ratio of 1.67, and [Ca]. [Pi] concentration products of 0.6, 1.35 or 2.4 mM2, with all solutions having an ionic strength of 0.15 M, and a pH of 7.0. After remineralization, the roots that were not treated with collagenase were incubated with the enzyme. The results indicate that remineralization of erosive lesions is surface-controlled and that of subsurface lesions diffusion-controlled. For both lesion types it was shown that the removal of collagen before remineralization did not affect the rate of mineral deposition in the root lesions. Nevertheless, remineralization in those lesions where accessible collagen had not been removed resulted in a significant reduction in the amount of degradable collagen. The observations of this study suggest that remineralization did not occur by nucleation of mineral on the organic matrix but rather by growth of residual crystals in the partially demineralized root tissue.

Susceptibility of the collagenous matrix from bovine incisor roots to proteolysis after in vitro lesion formation

The susceptibility of the organic matrix from permanent bovine incisor roots to proteolytic breakdown after in vitro lesion formation was investigated. Root surfaces were exposed to 0.1 M acetic acid, pH 4.0, to produce erosive lesions or to 0.1 M lactic acid, 0.2 mM methane hydroxy diphosphonate, pH 5.0, to produce subsurface lesions. After demineralization, the roots were treated with a bacterial collagenase. The quantity of enzyme-degradable collagen in the root tissue was found to be proportional to the calcium released during demineralization, until a plateau value was reached at calcium concentrations in solution of 3.3 mM at pH 4.0 and 2.7 mM at pH 5.0. The degradability of collagen was found to be substantially less in subsurface lesions than in erosive lesions. The presence of cementum-free areas did not affect the results. These findings suggest that the mineral component of the roots is composed of several fractions which differ in their solubility properties in weak acids.

Prevention of sucrose-induced demineralization of tooth enamel by chewing sorbitol gum

Measurements were made of the effect of chewing sorbitol gum on the intra-oral demineralization induced by rinsing with 10% sucrose solutions. Blocks of bovine enamel were covered with a layer of Streptococcus mutans IB1600, and mounted on palatal appliances that were worn by five subjects for defined periods of time. Enamel demineralization was determined by following changes in iodide penetrability (delta Ip) of the enamel surfaces. Delta Ip increased to a maximum of about 15 units between 30 and 45 min, while the pH of the S. mutans plaque dropped to below 4 by 15 min. Plaque pH returned to 4.9 by 60 min. Chewing sorbitol gum after the sucrose rinse minimized further increases in delta Ip and brought about a more rapid return of the S. mutans plaque pH toward neutrality. The effect of chewing gum was greater when chewing was initiated earlier so that, when gum was given at five min after the sucrose rinse, demineralization was only 37% of that obtained without gum. The findings confirm earlier reports on the effect of gum on plaque pH, and directly demonstrate the profound protective effects that chewing sorbitol gum can have on tooth enamel.

Dental and metabolic effects of lactitol in the diet of laboratory rats

1. Because so little is known about the properties of lactitol as a possible alternative bulk sweetener to sucrose, it was tested in two large-scale experiments in laboratory rats. Matched groups of caries-active Osborne-Mendel rats were fed on uniform diets containing lactitol and compared with a sucrose control in both experiments, plus a xylitol control in the first experiment. 2. In the early stages of the experiments weight gains and food utilization were better on the sucrose than on the lactitol regimens. Body-fat storage was higher on the sucrose than on the polyol regimens. 3. At the end of 8 weeks the mandibular molars were examined for dental plaque accumulation and dental caries. The dental caries scores when 160 g sucrose/kg in the diet was replaced by lactitol were lower by a highly significant margin, bringing them down to the same low level as those on a 160 g xylitol/kg regimen. 4. Testing lactitol in a manufactured food product, shortbread biscuits, in comparison with ordinary sucrose biscuits, showed differences in plaque scores (significant) and caries levels (highly significant), with 60% fewer lesions on the lactitol regimen. 5. The results confirm the low cariogenic potential of lactitol, but show metabolic differences compared with sucrose.

Effect of disease severity and pharmacotherapy of asthma on oral health in asthmatic children

Oral health was studied in a group of asthmatic children (n = 61). The children were divided in two groups, 5-10 and 11-18 yr of age. The individuals with asthma were further subgrouped with respect to the disease severity. Severe asthma was defined as more than 10 asthmatic attacks per year. This patient group had daily medication compared to children with moderate asthma (less than 10 asthmatic attacks/yr) who medicated temporarily. 55 age matched children from the same area made up the control group. All children were examined clinically and two bitewing radiographs were taken. The results showed no statistically significant differences concerning caries prevalence and gingival condition in asthmatic children compared to a healthy control group. The study shows that neither the asthma per se nor the disease severity affected the caries prevalence and gingival condition in asthmatic children.

Hydrogen selenide poisoning: an illustrative case with review of the literature

Hydrogen selenide is a non-metallic compound currently receiving attention in both medicine and electronics. Toxicity results in multiple symptoms, the most characteristic of which is a garlicky odor of the breath. A young woman exposed repeatedly to hydrogen selenide gas developed gastrointestinal complaints, dental caries, conjunctivitis, nail deformities, and garlicky breath. Other reported cases are discussed along with various proposed treatments.