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Inhibition of enamel demineralization by a bioerodible fluoridated resin
Abstract
To investigate the efficacy of a bioerodible fluoridated resin on inhibition of enamel demineralization.
Eighteen extracted permanent molars were sectioned mesiodistally to obtain 36 caries-free enamel surfaces. Each sample was prepared by painting an acid-protective varnish, excluding a 2 x 8 mm window on either the buccal or lingual surface. The windows of exposed enamel were randomly divided into three separate groups (n = 12). Group 1 received an application of a 5% (by weight) sodium fluoride varnish. Group 2 had an experimental 5% sodium fluoride bioerodible resin applied to the window. Group 3 was left untreated and acted as a control. The samples were then exposed to an artificial caries challenge for 17 days, until a visible white spot lesion had been created on the control group. The samples were brushed for 1 minute daily. Following the acid challenge, the teeth were sectioned longitudinally to obtain 100 microm sections. Sections were then photographed under polarized light. Quantitatively the areas of the lesions were measured by utilizing a computerized imaging system. Finally, a comparison was made between mean lesion sizes of the sample groups in order to determine their respective efficacy of enamel demineralization inhibition.
The mean areas (microm)2 of the artificial lesions (+/- SD) were: bioerodible fluoridated resin 3,785 +/- 1,794; fluoride varnish 7,362 +/- 2,853, and control 11,398 +/- 4,238. ANOVA was performed and identified a significant variance (P < 0.001). Tukey's multiple comparison test demonstrated that bioerodible fluoridated resin had significantly less enamel demineralization than the fluoride varnish and control groups (P < 0.05). The fluoride varnish group demonstrated significantly less enamel demineralization than the control group (P < 0.05).
... In a similar study conducted by Mazzavi et al,10 who evaluated the efficacy of a bioerodible fluoridated resin on the inhibition of demineralization and compared it with sodium fluoride varnish, found that bioerodible resin group demonstrated less demineralization compared with the sodium fluoride varnish group. They also concluded that the bioerodible resin used in their study was a potential alternative to topical fluoride in the prevention of caries. ...
A carious lesion is the accumulation of numerous episodes of de- and remineralization, rather than a unidirectional demineralization process. Tooth destruction can be arrested or reversed by the frequent delivery of fluoride or calcium/phosphorous ions to the tooth surface. The present study compared and evaluated the remineralization potential of sodium fluoride and bioactive glass delivered through a bioerodible gel system.
Longitudinal sections of artificial carious lesions, created at the gingivofacial surface of 64 pri-mary maxillary incisors were photographed under a polarized light microscope and quantified for demineralization. The sec-tions were repositioned into the tooth form and randomly mounted in sets of four that simulated an arch form. The teeth were divided into 4 groups: 1) sodium fluoride films, 2) bioactive glass films, 3) control films placed interproximally and 4) non-treatment group. Following exposure to artificial saliva for 30 days, the lesions were again photographed and quantified as above. The recorded values were statistically analyzed using Student's paired t-test for intragroup comparison, one-way ANOVA and Post-Hoc Tukey's test for pairwise comparison.
The sodium fluoride and bioactive gel groups showed significant remineralization compared with the control groups (P < 0.001).
Bioerodible gel films can be used to deliver remineralizing agents to enhance remineralization.
To examine the remineralization effects of a bioerodible fluoridated resin.
36 extracted permanent molars were suspended into an artificial caries solution to create an artificial caries-like lesion. Teeth were sectioned longitudinally to obtain 100 microm sections containing the artificial caries-like lesion, then photographed with polarized light microscopy in an imbibition media of water, representing a minimum of 5% pore volume. An acid-resistant varnish was applied to the surfaces of the sections, leaving only the natural external tooth surface and caries-like lesion exposed. The external tooth surface of 12 samples had 5% sodium fluoride varnish applied, 12 samples had 5% sodium fluoride bioerodible resin applied, and the remaining samples acted as controls. The sections were returned to the tooth, placed in an artificial saliva solution and brushed daily for 30 days. The sections were removed and photographed under polarized light as before. Using a computerized imaging system, the area of the body of the lesion was measured, comparing the same section before and after the 30-day experimental period to evaluate the remineralization process.
The mean percent area remineralization (+/-SD) was: bioerodible fluoridated resin 44.1 +/- 12.1; fluoride varnish 19.1 +/- 9.2; control 2.4 +/- 3.4. ANOVA indicated a significant variance among groups (P < 0.001). Tukey's multiple comparison test demonstrated the fluoridated resin to enhance remineralization significantly greater (P < 0.001) than the fluoride varnish and control and the fluoride varnish to enhance remineralization significantly greater (P < 0.002) than the control.
The time of contact between the product and enamel surface is important in ensuring the efficacy of fluoride varnishes. Thus, some alternatives could avoid fluoride loss to saliva and improve the anticariogenic action of the product. This study evaluated the effect of an experimental coat on the anticariogenic action of fluoride varnishes.
Enamel bovine blocks were selected by evaluating surface microhardness and randomized into five groups (n=24): placebo, Duraphat, Duraphat with coat, Duofluorid and Duofluorid with coat. Twelve blocks from each group were used to analyze calcium fluoride (CaF2) formed on enamel after treatment. The other 12 blocks were subjected to pH cycling for 7 days. The varnishes were kept on enamel for 6 h. Next, the percentage change of surface microhardness (%SMHC) and mineral loss (DeltaZ) were calculated. CaF2 retained and fluoride present in the pH-cycled solutions were also measured.
The use of the coat did not decrease %SMHC and DeltaZ, but all fluoride varnishes had better results when compared to the placebo (ANOVA and Kruskal-Wallis, respectively). The values from CaF2 formed were higher compared to the values of CaF2 retained (non-paired t test, p<0.05). There was a trend to decrease the amount of F in the solutions at the end of pH cycling (Kruskal-Wallis, p<0.05).
Although the experimental coat increased the formation of CaF2 on the enamel surface, it did not significantly improve the anticariogenic action of fluoride varnishes.
Abstract – Effect of applications of a sodium fluoride varnish, Duraphat®, on progress of initial caries lesions was studied in 11–13-year-old children. All 60 children included in the study had high caries activity and life-long exposure to fluoridated drinking water. The varnish was applied semiannually using the half mouth technique, and annual clinical and radiographic examinations were made for 3 years. The treatment had little effect on the progress of initial caries lesions present before the first application of varnish. The progress of caries lesions formed during the study was inhibited more distinctly, and the difference between test and control side in the rate of progress of caries lesions was highly statistically significant. Use of fluoride varnish seems to help to prevent further development of early caries lesions.
Abstract 251 9–12-yr-old children completed a 3-yr, double-blind, clinical trial of two caries preventive fluoride programs. Caries increments and progression patterns were compared in two groups of children who rinsed every fortnight with a 0.2% NaF solution or received biannual topical applications with a fluoride varnish (Fluor-Protector). Clinically recorded mean DPS increments were 3.3 ± 0.2 (SE) in the rinse group and 3.5 ± 0.2 in the varnish group. In both groups nearly half of these increments were recorded in the occlusal surfaces of second molars. The mean incremental DPS recorded radiographically on approximal surfaces of posterior teeth were 1.1 ± 0.2 and 1.5 ± 0.2 in the rinse and varnish group, respectively. None of the inter-group differences were statistically significant (p>0.05). Detailed analyses of the radiographic scores revealed a similar and extremely slow caries progression in the two study groups and they strengthened the conclusion of equal clinical efficacy of the two treatments. None of the fluoride programs had been able to change pre-established patterns of caries development among the children.
During recent years, the spectrum of methods of increasing the fluoride concentration in enamel has rapidly expanded. Regarding the agents to be applied topically to the teeth, studies by Muhlemann [1967], Mar-thaler et al. [1970], and Schmidt [1970] have indicated that the cumulated length of time over which the agent is in contact with the teeth is important for the cariostatic effectiveness. Therefore, a fluoride varnish with prolonged application time seemed to be of special clinical interest.
Previous studies have shown that topical application of the fluoride varnish Duraphat reduces caries incidence. The aim of the present study was to compare the caries inhibiting effect of a new fluoride varnish (Carex) containing 1.8% fluoride (F) with that of Duraphat (2.26% F). Informed consent was obtained from the guardians of 495 children 10-12 yr old in Voss Dental Health District (low F area). The children were randomly allocated to two groups. One group of subjects received 6-monthly application of Duraphat (n = 185), the other Carex (n = 165). Ethical considerations precluded the use of a placebo varnish. All participants received dental examinations including one pair of posterior bitewing radiographs and necessary dental care annually. One trained examiner interpreted bitewing radiographs blindly. Total 3-yr net DFS increment for 24 posterior approximal surfaces was 2.63 (SD = 3.81) in the Duraphat group and 2.12 (SD = 3.50) in the Carex group. DMFS increments based on 40 posterior occlusal and approximal surfaces were 5.21 (SD = 5.79) and 4.04 (SD = 4.92), respectively. Thus the results indicate a comparable efficacy for Carex and Duraphat at the caries activity level exhibited by these study participants.
One hundred and sixty 11-year-olds were randomly allocated to two experimental groups, one test (group 1) and one control group (group 2), for a 3-year clinical test comparing different modes of fluoride varnish treatment. In the test group, children received Duraphat varnish treatments 3 times a week, once a year. The children in group 2 were treated with Duraphat every 6 months. During the experimental period, children in group 1 received 9 fluoride varnish applications, and in group 2, 6 applications. Four bitewing radiographs were taken in each child each year for the measurements of the incidence and progression of proximal caries. Repeated fluoride varnish treatment with Duraphat, 3 times a week once a year, appears to inhibit proximal caries progression and development since the children in this group showed even a lower caries status, 1.3 +/- 0.3 DS, at the end of the study compared to 1.6 +/- 0.2 DS at the outset. In group 2, the children increased their caries status from 1.7 +/- 0.2 to 2.4 +/- 0.4 DS during the experimental period. The caries difference was statistically significant (p less than 0.05) between the two groups. A health economic comparison of the two modes of application showed 30% lower costs for the children in the test group based on time used for preventive measures and assumed filling therapy.
The efficacy of Duraphat varnish applications performed two or four times a year was compared in a 2-yr clinical trial. 254 children aged 9-13 yr and having higher than average DMFS values participated in the study. The children were randomly divided into two treatment groups. Clinical and radiographical examinations were performed at baseline and after 2 yr by one dentist. For the group receiving applications every 3 months, the 2-yr DMFS increment was 2.90 (SD 4.45) and for the group receiving applications every 6 months, 2.92 (4.47). There were no significant differences in DMFS increments between the groups for any type of tooth surfaces. Neither was there any difference between the groups when the children were divided into two subgroups on the basis of baseline DMFS values. The increments for the children with high (greater than or equal to 10) baseline DMFS values were 4.25 (4.81) and 4.30 (5.53) in the groups receiving applications four times and twice a year, respectively. The results suggest that fluoride varnish applications performed more frequently than twice a year may not provide additional caries protection in a population with relatively low caries activity.
The caries-preventive effect of Duraphat® lacquer versus fluoride mouthrinses was evaluated in a 5-year clinical trial. The lacquer group received Duraphat application every 6th month and a placebo rinse every 2nd week during the school year. The fluoride rinse group received a 0.2% sodium fluoride rinse every 2nd week during the school year and a placebo lacquer every 6th month. All children received regular dental examination and treatment in clinics established by the municipality in which the study took place. Fluoride content of the drinking water varied between 0.1 and 0.2 ppm F––. Caries was recorded clinically and radiographically and increments calculated after 3 and 5 years. On teeth erupted at baseline the clinical caries increment after 5 years was 2.96 DMF-S in the lacquer group and 2.77 DMF-S in the fluoride rinse group, evaluated for the 248 3rd grades completing the study. Caries increment in teeth erupting during the trial was 2.20 DMF-S in the lacquer group and 2.30 DMF-S in the fluoride rinse group. The corresponding figures for radiographic caries increment were 1,01 and 0.82 DMF-S for teeth erupted at baseline, and 0.59 and 0.45 DMF-S for teeth erupting during the trial. None of the differences were statistically significant. Mean time needed to apply the lacquer was approximately 4 min, when working with a chairside assistant and 6 min, when working without a chairside assistant.Copyright © 1986 S. Karger AG, Basel
The present study was carried out to examine the effect of application of a fluoride varnish (Duraphat) on experimentally produced caries in vivo. After a 4-wk period of cariogenic challenge on homologous pairs of premolars, Duraphat was applied on one of the teeth while the other was extracted and saved as a control. The Duraphat treated teeth remained in a cariogenic environment for a new period of 2 wk prior to extraction. All the control teeth displayed the classical characteristics of active incipient subsurface carious lesions. The Duraphat treated lesions showed an increase in surface porosity relative to their controls while the subsurface porosity was dramatically reduced. When examined in the SEM, the corresponding surface appeared smooth with a leveling out of the original surface irregularities. High power microscopy disclosed, however, a distinct network of intercrystalline spaces. Application of Duraphat prior to reestablishment of cariogenic challenge apparently gives rise to a marked redistribution of minerals in active initial carious lesions.
The aim of this study was to compare the effect of fortnightly rinsing with a 0.2% fluoride solution and two fluoride varnishes. A total of 204 ten- to 13-year-old children, in 24 school classes, participated in the study. The school classes were randomly divided into three groups. The first group rinsed with the fluoride solution every second week during the school year, and the second and third groups received semiannual applications of Duraphat® or Fluor Protector®, respectively. Clinical and radiographical examinations were performed at the baseline and after 2 years. The mean caries increments were adjusted for initial DMFS values and age. The increment in the Duraphat group was significantly lower than that in the rinsing group (p < 0.01) and in the Fluor Protector group (p < 0.05). The difference between the rinsing and Fluor Protector group was not statistically significant. The results suggest that the replacement of teacher-supervised fluoride rinses by semiannual application of Duraphat is worth considering.Copyright © 1987 S. Karger AG, Basel
The purpose of this study was to evaluate the separate effect of fluoride dentifrice, fluoride mouthrinsing and fluoride varnish on approximal dental caries. All 252 13-14-yr-old children at an elementary school were selected at random and divided among four groups for a 3-yr longitudinal study. Group 1 received a fluoride dentifrice for home care and a fluoride mouthrinse once a week. Group 2 received a fluoride dentifrice for home care and a placebo mouthrinse once a week. Group 3 received a fluoride dentifrice for home care and a fluoride varnish once every 3 months. Group 4 received a placebo dentifrice for home care and a fluoride rinse once a week. Fluoride rinsing did not give any additional effect compared with placebo-rinsing when a fluoride dentifrice was used for home care. Fluoride varnish gave a significant caries reduction compared with fluoride rinsing.