Showing papers in "Caries Research in 2002"

An in vitro oral biofilm model for comparing the efficacy of antimicrobial mouthrinses.

Abstract: The ability of commercial mouthrinses to reduce total viable counts of mixed microbial populations was examined using a previously developed in vitro model of supragingival plaque. Exploratory experiments aimed at fine-tuning the model indicated that optimal correspondence between in vitro and clinical results for chlorhexidine-containing formulations were obtained at a saliva:medium ratio of 70:30 (v/v); moreover, expanding the microbial population from 5 bacterial species to 5 bacterial species + Candida albicans had no noticeable impact on overall results. The efficacies of 12 different mouthrinse proprietary products containing chlorhexidine, hexetidine, octenidine, Triclosan, plant extracts, or aminefluoride/stannous fluoride vis-a-vis biofilm clearance were compared. All mouthrinses promoted a statistically significant reduction in microbial load compared to distilled water. The herbal- and phenolic-based products were substantially less effective than most chlorhexidine-containing mouthrinses, or mouthrinses containing hexetidine or octenidine. No significant difference between the plaque-clearing plaque-clearing abilities of Listerine and Meridol was observed. This polyspecies biofilm model can be a valuable tool for preclinical testing of antiplaque formulations, particularly during the product development stage.

Atraumatic Restorative Treatment: Clinical, Ultrastructural and Chemical Analysis

Abstract: With the purpose of checking, in vivo, the effect of atraumatic restorative treatment (ART) on the remaining demineralized dentin, 12 primary molars with deep occlusal lesions from children with ages ranging from 3 to 7 were evaluated. After lesion excavation, and before glass ionomer cement placement, dentin samples were collected from the pulpal wall of the cavity. After 3 months, the restorations were removed and new samples were collected. Six microareas of each sample were analyzed by X-ray energy dispersion spectrometer. Samples obtained before treatment were infected and intertubular dentin had a loosely organized collagen matrix, with well-defined collagen fibers. Following treatment, in addition to a drastic reduction of the amount of bacteria, the intertubular dentin was denser, with more compact and closely packed collagen fibers. An increased calcium concentration was observed in dentin collected after treatment (p < 0.001), suggesting tissue remineralization, but fluoride was not detected. We conclude that ART allows a one-session approach, with the purpose of creating more favorable conditions for the healing process.

Fluoride is unable to reduce dental erosion from soft drinks.

Abstract: The main aim of the present study was to compare the erosive capabilities of some fruit-flavoured drinks, fresh or saturated with CaF2, with their content of acids and with previous results from some carbonated soft drinks. The other aim was to measure and compare the rates of dissolution of CaF2 in some carbonated and non-carbonated drinks and water. Seven commercially available fruit-flavoured drinks were diluted for drinking. Two human molars, each with two approximately 4 × 4 mm windows, were exposed continuously to 500 ml of each drink with or without prior equilibration with CaF2 under gentle agitation for 48 h. The depths of the erosions were then measured on microradiographs made from sections. Dissolution rate of CaF2 was measured by suspending 0.5 g of the salt in 0.5 litre of the drinks for 2, 10 and 60 min followed by solution analysis. The pH of the drinks was 2.83–3.51. The amount of NaOH required to bring pH to 5.5 ranged from 12–42 mmol/l, which is more than the amount necessary for most carbonated soft drinks. Equilibration with CaF2 gave total fluoride concentrations of 3–8 ppm. The depths of the lesions induced by the drinks without added fluoride were 450–625 µm whilst those developed by the drinks equilibrated with CaF2 were 350–625 µm. The dissolution of CaF2 was faster in the carbonated drinks and in distilled water than in the non-carbonated drinks. In conclusion, non-carbonated fruit-flavoured drinks contain considerable amounts of acids which, in vitro, induce erosions in teeth similar to those induced by carbonated soft drinks. Saturation with CaF2 reduced the in vitro development of erosions by 28% induced by drinks with pH above 3; in drinks with pH below 3, erosions were not affected by pH, despite total fluoride concentrations of up to 20 ppm.

Evaluation of a Computer Program for Caries Risk Assessment in Schoolchildren

Abstract: The 'Cariogram' is an interactive PC program for caries risk evaluation. It takes into account the interactions between caries-related factors and expresses a graphic assessment of the risk. The aim of this study was to assess the caries risk in schoolchildren using the Cariogram and to evaluate the program by comparing the caries risk assessments with the actual change in DMF. A 2-year prospective study on 446 schoolchildren, 10-11 years old, was conducted. At baseline, data on general health, diet, oral hygiene and use of fluoride were obtained. Saliva analyses included mutans streptococci and lactobacilli counts, buffer capacity and secretion rate. DMFT and DMFS were calculated from records and bitewing radiographs. Scores were entered and caries risk was assessed. Re-examination for caries was done after 2 years. The children were divided into 5 groups according to the assessed caries risk at baseline. Where the Cariogram predicted a 0-20% (high risk), 21-40%, 41-60%, 61-80% and 81-100% (low risk) chance of avoiding new lesions, 8, 35, 42, 73 and 83%, respectively, had no new lesions 2 years later. Logistic regression analyses were carried out. When the Cariogram was included, only two factors, the Cariogram (p < 0.001) and the DMFS at baseline, i.e. past caries experience (p = 0.001), turned out to be significantly associated with caries increment. The Cariogram was the most powerful explanatory variable. When the Cariogram was excluded, lactobacillus count, mutans streptococci, diet intake frequency and DMFS at baseline were significantly associated with caries increment. The Cariogram predicted caries increment more accurately than any included single-factor model. How this finding can be translated into daily practice in the best and most practical way is a matter for future research.

A randomised controlled trial of the efficacy of supervised toothbrushing in high-caries-risk children

Abstract: Scottish children have one of the highest levels of caries experience in Europe. Only 33% of 5-year-old children in Dundee who developed caries in their first permanent molars by 7 brushed their teeth twice a day. High-caries-risk children should benefit if they brush more often with fluoridated toothpaste. The aim of this clinical trial was to determine the reduction in 2-year caries increment that can be achieved by daily supervised toothbrushing on school-days with a toothpaste containing 1,000 ppm fluoride (as sodium monofluorophosphate) and 0.13% calcium glycerophosphate, combined with recommended daily home use, compared to a control group involving no intervention other than 6-monthly clinical examinations. Five hundred and thirty-four children, mean age 5.3, in schools in deprived areas of Tayside were recruited. Each school had two parallel classes, one randomly selected to be the brushing class and the other, the control. Local mothers were trained as toothbrushing supervisors. Children brushed on school-days and received home supplies. A single examiner undertook 6-monthly examinations recording plaque, caries (D(1) level), and used FOTI to supplement the visual caries examination. For children in the brushing classes, the 2-year mean caries increment on first permanent molars was 0.81 at D(1) and 0.21 at D(3) compared to 1.19 and 0.48 for children in the control classes (significant reductions of 32% at D(1) and 56% at D(3)). In conclusion, high-caries-risk children have been shown to have significantly less caries after participating in a supervised toothbrushing programme with a fluoridated toothpaste.

Relationship among dental plaque composition, daily sugar exposure and caries in the primary dentition.

Abstract: The relationship among daily sugar exposure, dental plaque composition and caries patterns in the primary dentition is not known. Three groups of 20 children (18–48 months old) were studied: (1) carie

Caries incidence in young type 1 diabetes mellitus patients in relation to metabolic control and caries-associated risk factors.

Abstract: The aim of this study was to evaluate the caries incidence in a group of young patients with type 1 diabetes mellitus over a 3-year period from the onset of the disease in relation to metabolic contro

Pulpal responses to caries and dental repair.

Abstract: The dentine-pulp complex shows a broad spectrum of responses to caries of the dental tissues, which represents a summation of injury, defence and repair events taking place. The relative importance of these various events will reflect both the extent of disease activity and metabolic state of the tissues. This review examines the interplay between these events and the opportunities for tissue regeneration following caries.

Effects of glucose and fluoride on competition and metabolism within in vitro dental bacterial communities and biofilms.

Abstract: Antimicrobial effects of fluoride in vivo remain contentious Previous studies suggested that 1 m M NaF reduced acid production from glucose, and prevented the enrichment of bacteria

Effectiveness of glass-ionomer (ART) and amalgam restorations in the deciduous dentition: results after 3 years.

Abstract: This study compared the survival of restorations produced through the atraumatic restorative treatment (ART) approach using glass-ionomer with those produced through the traditional approach using ama

Prevalence, Distribution and Background Variables of Smooth-Bordered Tooth Wear in Teenagers in The Hague, The Netherlands

Abstract: The purposes of the study were: (1) to assess the prevalence and distribution of smooth-bordered tooth wear in teenagers, and (2) to investigate the relationship between smooth-bordered tooth wear and social background, dietary pattern, drinking habits, oral hygiene practices and caries prevalence. In The Hague, The Netherlands, a sample of 345 10- to 13-year-olds and 400 15- and 16-year-olds was clinically examined. The criteria for the assessment of smooth-bordered tooth wear ('smooth wear') were in line with the diagnostic criteria for erosion developed by Lussi (1996). In the age group 10-13 years, the percentage of subjects with visible smooth wear (SW1 threshold) was 3% and in 1 subject (0.3%), deep smooth enamel wear was found. Due to the low prevalence, the results for this age group were not analysed further. In the age group 15-16 years, the proportion of subjects with visible smooth wear (SW1 threshold) was 30% and that with at least deep smooth enamel wear (SW2 threshold) 11%. Smooth wear into dentine was found in 1 subject. First molars and upper anterior teeth were affected predominantly. A significant effect on visible smooth wear (SW1 threshold) was found for gender and social background. At mouth level, no significant influence was found for dietary patterns, drinking habits or oral hygiene practices. The caries prevalence was similar in subjects with and without smooth wear.

Effect of a mouthrinse containing selected propolis on 3-day dental plaque accumulation and polysaccharide formation.

Abstract: The aim of this study was to evaluate the effect of a mouthrinse containing propolis SNB-RS on 3-day dental plaque accumulation. Six volunteers took part in a double-blind crossover study performed in two phases of 3 days. During each phase the volunteers refrained from all oral hygiene and rinsed with 20% sucrose solution 5 times a day to enhance dental plaque formation and with mouthrinse (placebo or experimental) twice a day. On the 4th day, the plaque index (PI) of the volunteers was scored and the supragingival dental plaque was analyzed for insoluble polysaccharide (IP). The PI (SD) for the experimental group was 0.78 (0.17), significantly less than for the placebo group, 1.41 (0.14). The experimental mouthrinse reduced the IP concentration in dental plaque by 61.7% compared to placebo (p < 0.05). An experimental mouthrinse containing propolis SNB-RS was thus efficient in reducing supragingival plaque formation and IP formation under conditions of high plaque accumulation.

Relationship between sports drinks and dental erosion in 304 university athletes in Columbus, Ohio, USA

Abstract: Acidic soft drinks, including sports drinks, have been implicated in dental erosion with limited supporting data in scarce erosion studies worldwide. The purpose of this study was to determine the prevalence of dental erosion in a sample of athletes at a large Midwestern state university in the USA, and to evaluate whether regular consumption of sports drinks was associated with dental erosion. A cross-sectional, observational study was done using a convenience sample of 304 athletes, selected irrespective of sports drinks usage. The Lussi Index was used in a blinded clinical examination to grade the frequency and severity of erosion of all tooth surfaces excluding third molars and incisal surfaces of anterior teeth. A self-administered questionnaire was used to gather details on sports drink usage, lifestyle, health problems, dietary and oral health habits. Intraoral color slides were taken of all teeth with erosion. Sports drinks usage was found in 91.8% athletes and the total prevalence of erosion was 36.5%. Nonparametric tests and stepwise regression analysis using history variables showed no association between dental erosion and the use of sports drinks, quantity and frequency of consumption, years of usage and nonsport usage of sports drinks. The most significant predictor of erosion was found to be not belonging to the African race (p < 0.0001). The results of this study reveal no relationship between consumption of sports drinks and dental erosion.

In vivo repeatability and reproducibility of the quantitative light-induced fluorescence method.

Abstract: In vivo repeatability and reproducibility of the quantitative light-induced fluorescence (QLF) method were tested with respect to three variables: lesion area, and average and maximum changes in lesion fluorescence. To test the image-capturing stages, three analysts each captured images of 15 incipient smooth surface lesions in vivo, and the images were analysed by one of the analysts. To test the analytical stage of the method, three analysts analysed the images of 15 in vivo incipient smooth surface lesions. For the image-capturing stage, inter-examiner reliability showed an intra-class correlation coefficient (r) between 0.95 and 0.98. For the analytical stage, intra-examiner reliability for all three analysts showed a value of r between 0.93 and 0.99. Inter-examiner reliability showed a value of r between 0.95 and 0.99. It was concluded that the in vivo repeatability and reproducibility of the QLF method are excellent.

Residual Caries Detection Using Visible Fluorescence

Abstract: This study investigated the ability of a new fluorescence method to detect residual caries in vitro. Gross caries was removed from 40 teeth with D2 caries. Samples were excited with violet-blue light

Antibacterial activity of restorative dental biomaterials in vitro.

Abstract: This study investigated the antibacterial effects against Streptococcus mutans of a fine-hybrid resin composite (FH-RC; Tetric ceram), an ion-releasing resin composite (Ariston pHc), a self-curing glass ionomer cement (SC-GIC; Ketac-Molar), a resin-modified GIC (RM-GIC; Photac-Fil), and a zinc oxide eugenol cement (ZOE; IRM). In a novel assay, bacterial suspensions were placed into narrow 20-µl conical cavities within the materials. After 0, 4, 8, 24, 48 h and 1 week of incubation, the suspensions were removed from the restoratives and the numbers of viable bacteria were determined. After incubation periods of 8 h or more, all restorative materials except the FH-RC showed significant growth inhibition when compared with controls. The strongest antibacterial activity was observed with ZOE. The inhibitory effect of Ariston pHc was similar to that of the SC-GIC and the RM-GIC. In the second assay, growth inhibition was evaluated in liquid cultures by incubating eluates of the materials with suspensions of S. mutans. Bacterial growth was determined up to 6 h by measuring absorption at 600 nm. The most marked inhibitory effect was again observed with ZOE. The SC-GIC caused a significant inhibition at all time intervals but the FH-RC, the RM-GIC and Ariston pHc exhibited no significant antibacterial effects. It is recommended to employ more than one method for assessing the antibacterial potential of restorative materials. Long-term clinical trials are necessary to determine whether the antimicrobial effects of dental materials are able to reduce the risk of secondary caries formation.

Light-induced fluorescence studies on dehydration of incipient enamel lesions.

Abstract: Changes in the hydration state of enamel affect its optical qualities, such as light scattering and fluorescence. In this study, the rate of fluorescence loss was measured when incipient enamel lesions with different de-remineralization history were left to dehydrate. Four groups of lesions were studied. In groups A, B and C, the lesions were prepared in vitro in an acid-gel system. Group A was kept as control, and groups B and C were remineralized (4 weeks) without and with 1 ppm F in solution, respectively. Group D consisted of natural incipient lesions. Enamel fluorescence was measured for all lesions immediately after removal from water and subsequently at short intervals for 30 min. The change in fluorescence with dehydration varied between the groups. In lesions from groups A and B, it followed a double exponential decrease, while in lesions from groups C and D, it followed a mono-exponential decrease. In all groups, the fluorescence of sound surfaces declined mono-exponentially. The ‘fractional fluorescence difference’, defined as (Lsound – Lcarious )/Lsound, became constant after periods of dehydration of about 5, 5, 20 and 5 min for groups A to D, respectively. The observation of the change of fluorescence with dehydration should be taken into consideration when planning studies that use fluorescence as an assessment method. However, it might also be used to gain insight into the properties for fluid transport inside the various lesions, relevant to de-remineralization or fluoride treatments.

Validity and Reproducibility of a Laser Fluorescence System for Detecting the Activity of White-Spot Lesions on Free Smooth Surfaces in vivo

Abstract: The aim of the study was to determine the reproducibility and validity of DIAGNOdent in detecting active and arrested caries lesions on free smooth surfaces. Volunteers were selected from state school

Plaque fluoride concentrations are dependent on plaque calcium concentrations.

Abstract: Despite the 1,000-fold difference between the fluoride concentrations ([F]) in dentifrices and fluoridated drinking water, clinical and epidemiological studies have shown that they have similar carios

Remineralisation of enamel lesions with daily applications of a high-concentration fluoride gel and a fluoridated toothpaste: an in situ study.

Abstract: The inhibition of enamel demineralisation and the enhancement of remineralisation are positively but not linearly related to the concentration of fluoride, especially when high fluoride concentrations are used. The aim of this in situ experiment was to determine the maximum amount of enamel remineralisation that can be achieved with daily applications of very high concentrations of fluoride. For this purpose we compared the efficacy of a daily application of fluoridated topical gel (12500 ppm F, partly as NaF, Olafluor and Dectafluor, pH 4.5) in combination with a fluoridated toothpaste (1450 ppm F as NaF), with fluoridated toothpaste alone. Participants (n = 26, with partial dentures) were fitted with a demineralised enamel specimen (mean mineral loss of 1674 vol%.micro m) and were instructed to use one of the two fluoride treatments. After 4 weeks of treatment, the specimens were retrieved, a section was cut and analysed with microradiography. The remainder of each of the specimens was used for analysis of the 'loosely bound' and 'bound' fluoride. Fluoride was measured with gas-liquid chromatography. After 4 weeks in the mouth, the original lesion was reduced in size by 54% in the toothpaste + gel group (n = 14) and by 44% in the toothpaste-only group (n = 12), but the difference between the groups was not statistically significant. The mineral content profiles showed remineralisation of the lesions throughout the depth of the lesion. The enhancement of remineralisation by the high amounts of fluoride was most pronounced in the surface layer. For both the 'loosely bound' and 'bound' fluoride, a statistically significant increase in fluoride concentration could be found in the toothpaste + gel group. In the 4-week in situ period the use of high amounts of fluoride resulted in a maximum remineralisation rate. This is illustrated by an increase in remineralisation and higher fluoride concentrations in the toothpaste + gel group compared to the toothpaste-only group.

Remineralization of Advanced Root Dentin Lesions in vitro

Abstract: The possibility for remineralization of advanced root dentin lesions was investigated in vitro. Lesions were produced in acidic buffer solution with 0.1 and 0.5 ppm fluoride, for 3 and 5 weeks, respec

Further modification to soft drinks to minimise erosion. A study in situ.

Abstract: Soft drinks have been successfully modified to reduce enamel erosion The aim of this study was to further modify an original low erosive blackcurrant drink product by the addition of a gum, to manipulate more favourably other drink parameters The study was a single-blind, randomised four treatment crossover design involving 12 healthy volunteers During 10 working-day study periods, subjects wore enamel samples in the mid palatal region of a removable appliance Specimens were taped to expose a 2-mm enamel window The drinks under test were: (1) Orange juice, (2) Original blackcurrant drink, (3) Water, and (4) Experimental blackcurrant drink Drinks were imbibed at 250-ml volumes 4 times a day during appliance wearing from 0900 to 1700 Appliances were removed at lunchtime Measurements of specimens were made at baseline, 2, 5 and 10 days using a profilometer One 5-day and one 10-day specimen from each subject during each treatment were ultrasonicated Significant differences, in erosion between drinks, were seen at days 5 and 10 Comparisons of preselected pairs of drinks of interest showed significantly reduced erosion by the two blackcurrant drinks compared to orange juice with no significant differences from water The original blackcurrant drink produced significantly less erosion than the experimental drink Ultrasonication removed enamel from the Orange juice specimens but very little from those exposed to water and the two blackcurrant drinks Extrapolating the effects of both blackcurrant drinks suggested that alone they should not cause significant clinical erosion in a lifetime's intake of 1 litre per day

In vitro acid resistance of CO2 and Nd-YAG laser-treated human tooth enamel.

Abstract: The purposes of this study were to test the effectiveness of laser treatment (pulsed CO2 and pulsed Nd-YAG) on in vitro acid resistance of human enamel. Thirty enamel surfaces were prepared from 10 extracted permanent premolars (3 surfaces per tooth). Two experimental surfaces on each tooth were irradiated with either CO2 or Nd-YAG lasers. All specimens were demineralized in 10 ml lactate buffer for 24 or 72 h after laser treatment. After 24-hour acid treatment the mean concentration of calcium that dissolved into the lactate buffer in the CO2 laser group was significantly less than in the control group, while the dissolved calcium concentration in the Nd-YAG laser group did not differ from the control group (p > 0.05). The erosion depth in the CO2 laser group was significantly shallower than in the Nd-YAG laser group (p 2 laser-treated tooth enamel was more resistant to acid challenge than was Nd-YAG laser-treated enamel, given the same fluence, but neither type of laser increased acid resistance of subsurface enamel.

Susceptibility of Streptococcus mutans and Streptococcus sobrinus to cell wall inhibitors and development of a novel selective medium for S. sobrinus.

Abstract: Representative strains of Streptococcus mutans and Streptococcus sobrinus showed differences in susceptibility to members of the monobactam group of β-lactam anti

Effect of Cervitec on mutans streptococci in plaque and on caries formation on occlusal fissures of erupting permanent molars.

Abstract: The aim of this study was to evaluate the effect of Cervitec on the abundance of mutans streptococci (MS) in occlusal dental plaque and on 2-year caries increment of partly erupting first permanent molars. Sixteen healthy schoolchildren aged 6-8 years, with at least 2 sound contralateral partly erupted permanent molars, received diet counselling and daily parental supervised toothbrushing with a fluoride dentifrice. Stimulated saliva samples were collected at baseline and after 1 year to evaluate MS levels. In a split-mouth design, Cervitec varnish was applied to one of the teeth at baseline and after 3 and 6 months, while the other tooth in the same jaw was a control. At the 9-month follow-up the teeth were in occlusal contact. At this time, varnish was not applied. At 3 and 6 months after the first application of varnish a significant suppression of MS was observed in plaque. Caries investigations, performed at baseline and every 3 months during the 2 years after the start of the study, showed that all the teeth treated with the varnish were free of caries after 2 years, whereas 8/16 control teeth developed incipient caries. In conclusion, our results suggest that treatment with Cervitec reduces MS in plaque on erupting permanent molars and can lead to a significant decrease in caries incidence.

Prospective study of the effect of post-brushing rinsing behaviour on dental caries.

Abstract: Previous studies have indicated that rinsing the mouth with a beaker of water after toothbrushing may compromise the caries reducing effect of fluoride toothpaste. A 3-year clinical trial of daily supervised brushing with fluoride toothpaste at school was used to test the effect of post-brushing rinsing with water on caries increment. A total of 407 children, mean age 11.8 years, attending three schools in Kaunas, Lithuania were enrolled following informed consent of the children and their parents. Caries was recorded at baseline and annually for 3 years. During the study, children in two schools (A and B) performed daily supervised brushing with a 1,500-ppm fluoride toothpaste. Children in school A rinsed their mouths thoroughly with a beaker of water after toothbrushing whereas children in school B were only permitted to spit out once after brushing. Furthermore, the children in these schools were supplied with toothpaste and toothbrushes for use at home and in school. A third school (C), without daily brushing and without supply of toothpaste, served as control. Compliance with the protocol was consistently better in school B. After 3 years 276 children were available for examination. Three-year DMFS increments, including non-cavitated lesions (mean, 95% CI), were: school A, 6.8 (5.3; 8.3); school B, 6.2 (4.6; 7.8), and school C, 12.4 (10.6; 14.1). Mean increments for schools A and B did not differ significantly but were both significantly lower than those of school C (p< 0.001). It is concluded that post-brushing rinsing with water, under the conditions of this study, does not significantly affect the caries reducing effect of a fluoride toothpaste.

Fluoride concentration and pH of iced tea products.

Abstract: The objective of this study was to determine the fluoride concentration and pH of 44 iced tea samples and hence to assess the possible role of these beverages as systemic fluoride source as well as their potential cariogenic and erosive character. Ten tea samples were available as a granular instant powder, and 34 as ready-to-drink liquid products. The iced teas contained different types of sugar alone or in combination with maltodextrin, glucose syrup and noncaloric sweeteners. In one product, only acesulfame and aspartame were established. All samples contained lemon juice or citric acid as an additive. The pH ranged from 4.04 to 2.63 and the titrated amount of base to pH 7.0 from 0.75 to 2.39 mmol NaOH/50 ml. The fluoride concentrations measured were 2.0 ppm in another 2 products. In conclusion, most of the iced teas studied contained considerable fluoride concentrations. If infants ingest larger amounts of them because of their sweet taste, there is a risk of uncontrolled overdosing as a result of additional fluoride intake from other sources at the same time. Furthermore, the majority of the products revealed a highly cariogenic character and finally, all the iced teas appear to be acidic enough to cause dental erosion if these refreshments were excessively consumed from nursing bottles.

The effect of 6-monthly application of 40% chlorhexidine varnish on the microflora and dental caries incidence in a population of children in Surinam.

Abstract: This study is aimed at determining whether a commercially available varnish, containing 40% chlorhexidine, is able to reduce the numbers of mutans streptococci and lactobacilli in saliva, in a moderately caries-active population in Surinam. 238 children, ages 13-14 years, were selected from different schools in Paramaribo, Surinam. From these children, total dental status was recorded and saliva samples were taken. At baseline and every 6 months, a 40% chlorhexidine varnish (EC40) was applied. The control group received a neutral gel that did not contain chlorhexidine. The numbers of salivary mutans streptococci and lactobacilli were calculated by standard methods, and the caries status was recorded every 12 months. The study lasted 30 months. The results indicate that chlorhexidine varnish did not decrease the numbers of cariogenic bacteria, nor did it decrease caries progression. Moreover, in this population with a low dental health care, children with lactobacilli present in the saliva above our detection level, the chlorhexidine varnish even tended to increase caries progression, possibly due to selection of aciduric and acidogenic oral bacterial species. We therefore conclude that 40% chlorhexidine varnish is not likely to decrease caries in children in a high-treatment-need population without treatment of the sources of infection.

Dental Caries and Developmental Defects of Enamel in Relation to Fluoride Levels in Drinking Water in an Arid Area of Sri Lanka

Abstract: The study was conducted to assess caries and developmental defects of enamel in relation to fluoride levels in drinking water and the association between caries experience and the severity of diffuse

Changes in lactate and other ions in plaque and saliva after a fluoride rinse and subsequent sucrose administration.

Abstract: The purpose of this study was to examine plaque and saliva composition after a fluoride rinse and subsequent sucrose application. Fifteen subjects accumulated plaque for 48 h, and then rinsed with a fluoride rinse based on 228 microg/g (ppm) Na2SiF6 and some received no rinse. After 60 min, upper and lower buccal molar plaque samples and 1-min saliva samples were collected. The subjects then rinsed with 10% g/g sucrose solution, and 7 and 15 min later, a second and a third set of samples were collected. Plaque fluid and clarified saliva were then recovered from these samples by centrifugation, and the remaining plaque acid extracted. The plaque fluid, centrifuged saliva, and plaque extract samples were then analyzed using micro techniques for pH, free calcium, phosphate, organic acids (plaque fluid and saliva only) and fluoride. Considering both the fluoride rinse and no-rinse groups, the most notable compositional changes in saliva 7 min after the sucrose rinse were pH -0.40 unit, free calcium 0.42 mM, lactate 5.2 mM, phosphate -1.3 mM, and fluoride 2.8 microM; while in plaque fluid, the corresponding changes were pH -1.59 unit, free calcium 1.5 mM, lactate 35 mM, phosphate -1.6 mM and fluoride -26 microM. After sucrose rinsing, undersaturation was found with respect to dicalcium phosphate dihydrate in saliva and plaque fluid and with respect to tooth enamel in some plaque fluid samples. Plaque fluid composition appeared to be strongly influenced by salivary clearance, diffusive loss of ions into the water phase of the rinse, and lower jaw pooling of the sucrose and fluoride components of the rinses. After the experimental rinse, the fluoride concentration in plaque fluid [86 +/- 22 mM (upper molar site), 162 +/- 150 mM (lower molar site)], saliva (26 +/- 18 mM), and whole plaque [99 +/- 97 microg/g (upper molar site), 197 +/- 412 microg/g (lower molar site)] was comparable to the values in previous studies using this rinse. These very high plaque fluid fluoride concentrations, compared with the 'no-rinse' samples, induced an approximately 0.3-unit increase in the plaque fluid pH 7 min after the sucrose rinse, a small decrease (approximately 20%) in lactate production and a modest increase in enamel saturation. Although these changes were all statistically significant, no correlation was found between the decrease in lactate concentration and plaque fluid fluoride, pH or whole plaque fluoride.