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At least 613 records · Page 34Linked to original sources
PubMed2001

Effect of cavity varnish, amalgam liner or dentin bonding agents on the marginal leakage of amalgam restorations.

The purpose of this in vitro study was to compare marginal leakage of Class II amalgam restorations lined with different agents (two new generation dentin bonding systems, a cavity varnish and an amalgam liner). Forty freshly extracted human molar teeth were divided into five groups. Class II preparations were prepared in the mesial and distal surfaces of each molar. While the cavities in two groups were lined with two new generation bonding systems, the other two groups were treated with an amalgam lining material and a cavity varnish. Fifth group was used as control, without any lining. Amalgam* was hand-condensed into each preparation. Specimens were thermocycled, stained and sectioned. Microleakage was graded using a stereomicroscope. Mean microleakage scores for occlusal and cervical margins were calculated and analysed. For the leakage values on occlusal margins, Kruskal-Wallis test indicated no significant difference in all groups. For the leakage values on cervical margins, Kruskal-Wallis test indicated significant difference in four groups when compared with controls (P < 0.001). On the other hand, there was no significant difference between the occlusal and cervical leakage values in each group.

Calcium Fluoride↗
PubMed1998

Effects of various methods of chlorhexidine application on shear bond strength.

Chlorhexidine has been applied on the teeth and over orthodontic appliances during treatment in order to reduce bacterial colonization. The purpose of this study was to determine whether the application of chlorhexidine with or without a sealant, to the etched enamel will affect the shear bond strength and the bracket/adhesive failure modes of orthodontic brackets. A total of 132 extracted third molars were cleaned and then divided into 6 groups of at least 20 teeth each. The teeth were etched with a 37% phosphoric acid gel and a sealant was applied in 5 of the groups. Stainless steel orthodontic brackets were then bonded with the Transbond XT bonding system. The chlorhexidine was applied to the teeth either as a prophylactic paste or as a varnish under the following conditions: (1) as a varnish over the bracket and tooth surfaces after the bonding procedure was completed; (2) as a prophylactic paste containing 0.12% chlorhexidine over the intact enamel i.e., before etching; (3) mixed with the sealant and applied to the etched enamel before bonding, (4) as a varnish applied to the etched enamel with no sealant used; (5) as a varnish over the light cured sealant; and (6) as a varnish over the sealant before the sealant was light cured. All teeth were mounted in phenolic rings and stored in deionized water at 37 degrees C for 48 hours. A Zwick Universal Testing Machine was used to determine shear bond strengths. The residual adhesive on the enamel surface was evaluated with the Adhesive Remnant Index. The analysis of variance and chi square tests were used to compare the six groups. Significance was predetermined at the p < or = 0.05. The findings in this study indicated that shear bond strength was not significantly affected when chlorhexidine was applied; (1) over the bracket and tooth surfaces after the bonding procedure was completed (mean = 12.3 +/- 3.1 MPa), (2) as a prophylactic paste over the unetched enamel surface before the bonding procedure is initiated (mean = 9.6 +/- 2.3 MPa), and (3) when the varnish was premixed with the sealant and applied on the etched enamel surface (mean 11.8 +/- 2.1 MPa). On the other hand, in all the experimental groups in which the chlorhexidine varnish was applied as a layer on the etched enamel surface or over the sealant, shear bond strength values and bracket failure rates were of a magnitude that made them clinically unacceptable.

Acid Etching, Dental↗
PubMed2001

Effects of combined application of antimicrobial and fluoride varnishes in orthodontic patients.

A randomized prospective clinical study, with 220 patients scheduled for fixed orthodontic therapy, was conducted to test the hypothesis that application of an antimicrobial varnish in combination with a fluoride varnish (group 1) is significantly more efficient in reducing white spot lesions on the labial surfaces than application of the fluoride varnish alone (group 2). The effects of the antimicrobial varnish on the occurrence of gingivitis and plaque formation were also studied. A third aim was to investigate whether white spot lesion development could be predicted early during treatment. The antimicrobial varnish significantly reduced the number of mutans streptococci in plaque during the first 48 weeks of treatment. This effect did not result in significantly less development of white spot lesions on the labial surfaces compared with the group receiving only the fluoride varnish application. There was however a clear trend that the combination of the antimicrobial and fluoride varnishes more effectively reduced the increments of new lesions on the maxillary incisors. It was speculated that this could be due partly to an inhibiting effect of the antimicrobial varnish in an area with low oral clearance (with low pH and loss of fluoride) and partly to an inhibiting effect of the varnish on mutans streptococci. No significant differences between the groups with respect to gingivitis and plaque were found. Lesion development was difficult to predict early after bonding, despite a number of caries-relevant parameters of orthodontic importance. The best predictors for white spot lesions at debonding were visible plaque and mutans streptococci (eg, the level of oral hygiene and thus the cariogenic challenge) around the appliance shortly after bonding.

Adolescent↗
PubMed2002

Effect of fluoride varnish on demineralization adjacent to brackets bonded with RMGI cement.

Far too often a less-than-optimal esthetic result occurs after orthodontic treatment due to demineralization of enamel adjacent to fixed orthodontic appliances in patients with inadequate oral hygiene. In vitro studies have shown that a resin-modified glass ionomer (RMGI) cement and a fluoride varnish might help clinicians combat this problem. The purpose of this study was to evaluate, in vitro, the effect of a fluoride-releasing cavity varnish on inhibition of enamel demineralization adjacent to orthodontic brackets bonded with RMGI and composite resin cements. Brackets were bonded to 48 extracted human third molars. Half were bonded with a composite resin (Transbond, 3M Unitek, Monrovia, Calif) and half with an RMGI (Fuji Ortho LC, GC America, Alsip, Ill). Each group was further divided into 2, with half receiving an application of fluoride-releasing varnish (Duraflor, Pharmascience, Montreal, Québec, Canada). The samples were cycled in an artificial caries solution for an hour twice daily for 31 days. After each caries challenge, the teeth were brushed with a soft toothbrush to simulate normal mechanical wear of the varnish. The loss of fluoride varnish was timed. Teeth were sectioned longitudinally and photographed under polarized light microscopy. Mean lesion depth was measured, and analysis of variance (ANOVA) (P <or=.0001) and the Duncan multiple range test (P <or=.05) indicated significant differences among the groups. Teeth bonded with composite resin showed a 35% reduction in mean lesion depth when fluoride varnish was applied. Teeth bonded with RMGI cement showed no significant differences in lesion depth between varnish and nonvarnish groups. Both RMGI groups had 50% smaller mean lesion depths when compared with the composite resin group without fluoride varnish. Samples bonded with RMGI cement illustrated a wedge effect, with lesion depth shallower near the bracket. A chi-square test showed that the fluoride varnish was lost significantly faster in samples bonded with Fuji Ortho LC (P =.013). Although the fluoride varnish could not prevent demineralization, it appears to be beneficial in reducing lesion formation. Clinicians should consider applying fluoride varnish on areas of enamel that exhibit demineralization or are at risk of demineralization in patients with poor oral hygiene.

Acrylic Resins↗
PubMed2003

Effect of a fluoride varnish on the margin leakage and retention of luted provisional crowns.

STATEMENT OF PROBLEM: Provisional crowns cemented with provisional luting agents are susceptible to washout, margin leakage, and secondary caries when placed for a prolonged period. PURPOSE: This study was conducted to determine the effect of combining a varnish containing 2.26% NaF with 2 provisional luting agents on the margin leakage and retention of provisional crowns. MATERIAL AND METHODS: Acrylic resin provisional crowns were fabricated for 8 shoulder-prepared molars. The eight provisional (N=24) crowns were luted individually with Temp-Bond (TB), Freegenol (FG), or Duraphat (DU). Specimens were thermocycled 500 times (5 degrees and 60 degrees C) with a 1-minute dwell time, stored in 100% relative humidity at 37 degrees C for 6 days, and then immersed in a 0.5% Gentian violet solution for 24 hours. Seven days after cementation, a removal test of the crowns (shear retention test) was conducted with a universal testing machine at a crosshead speed of 5 mm/min. Retention was determined as the maximum recorded force needed for crown dislodgment. DU varnish was applied to the inner surface of the dislodged crowns with no removal of the cement layer TB, FG (N=16). The crowns were relined with a 0.5-mm layer of acrylic resin and luted with a combination of luting agent and DU (TB, FG) N=16. No luting agent (NC) served as the control (N=8). Results were analyzed with the Wilcoxon matched-pairs signed-ranks test. Leakage at the margins was assessed with a 4-level dye penetration scale, and statistical differences were identified with a chi(2) test. All hypothesis testing was conducted at the 95% level of confidence. RESULTS: The mean 7-day retention forces were as follows: 44.5 N (Temp-Bond), 51.6 N (Freegenol), and 35.9 N (Duraphat). There were no significant differences among these values. Duraphat combined with Freegenol decreased the retention of provisional crowns, but Duraphat combined with Temp-Bond increased the retention of provisional crowns by 69-145%. Duraphat alone and in combination with both provisional luting agents significantly reduced margin leakage (P<.05). The least margin leakage was evident when the provisional crowns were luted with Duraphat alone. CONCLUSION: With regard to retention and margin leakage, the results of this study suggest that Duraphat varnish can be successfully used as provisional luting agent for single provisional crowns.

Acrylic Resins↗
PubMed2003

In vitro evaluation of fluoride varnish on overdenture abutments.

STATEMENT OF PROBLEM: No clinical study has evaluated the efficacy of fluoride varnish as a topical fluoride agent for the protection of overdenture abutments from dental caries. PURPOSE: This study assessed the efficacy of a fluoride varnish in protecting overdenture abutments from demineralization in an in vitro environment. MATERIAL AND METHODS: Eighty caries-free, extracted teeth were sectioned and domed immediately below the cementoenamel junction, simulating overdenture abutment preparations. Acid resistant nail varnish was painted on all surfaces except for a window (1 x 4 mm) on the prepared occlusal dentin surfaces. Teeth were randomly divided into 4 groups of 20 specimens: control, washed with deionized/distilled water; Daily Gel, treated with Karigel-N (5,000 ppm) for 4 minutes daily; Weekly Gel, treated with Karigel-N for 4 minutes weekly; and Weekly Varnish, treated with Duraflor (22,600 ppm) weekly. The varnish was removed using a blade 24 hours after each application to simulate the clinical loss of the varnish. Teeth were then placed in a cycle of demineralization (2.2 mMol/L CaCl(2)2H(2)O, 2.2 mMol/L KH(2)PO(4), and 50 mMol/L acetic acid at pH 4.3) for 6 hours and remineralization (1.5 mMol/L CaCl(2)2H(2)O, 0.9 mMol/L KH(2)PO(4), and 150 mMol/L KCl at pH 7.0 for 17 hours) for 21 days. Half the teeth in each group were brushed with no dentifrice for 10 seconds, twice daily. Teeth were sectioned at 100 +/- 10 microm buccolingually and evaluated under polarized light microscopy and contact microradiography. The depth of each lesion and the width of the remineralization bands were measured (mm). Analysis of variance models and T-tests were used to assess the effects of different treatments (alpha=.05). Duncan multiple range tests were then chosen as post hoc tests to evaluate the statistical significance of all pairwise comparisons. RESULTS: The control group had the deepest lesions (mean depth 400 +/- 39 microm). The lesions from the varnish and daily gel groups were significantly shallower than the lesions in both the control group and the weekly gel group. The remineralization bands in the varnish group were 52% wider than the control group bands. However, the daily gel group had the largest increase in band width (117% increase) compared with the control group. There were significant differences between all groups for net depth (lesion depth minus the remineralization band) (P<.0001). Daily application of fluoride gel was significantly more effective than the other treatments tested. Brushing was not a significant factor. CONCLUSION: Within the limitations of this in vitro study, treatment of overdenture abutment with various topical fluorides significantly inhibited demineralization and enhanced remineralization of cut occlusal dentin surfaces. Daily use of Karigel-N was the most effective treatment, followed by the weekly application of Duraflor varnish.

Analysis of Variance↗
PubMed2004

Professional fluoride varnish treatment for caries control: a systematic review of clinical trials.

The aim of this paper was systematically to evaluate the caries-preventive effect of professional fluoride varnish treatments. A search of the literature for articles published between 1966 and August 2003 was carried out in electronic databases, reference lists of articles, and selected textbooks in accordance with the strategy of the Swedish Council on Technology Assessment in Health Care. Out of 302 identified papers, 24 randomized and controlled clinical trials comparing fluoride varnish with placebo, no active treatment or other fluoride preventive regimens of at least 2 years' study duration were included. The trials that met the inclusion criteria were assessed independently and systematically by at least two reviewers and scored from A to C according to predetermined criteria for methodology and performance. The main outcome measure was the preventive fraction expressed as a percentage. The results displayed limited evidence (evidence level 3) for the caries preventive effect of topical applications of fluoride varnishes in permanent teeth. The average prevented fraction was 30% (0-69%) when compared with untreated controls. Inconclusive evidence (evidence level 4) was found for fluoride varnish treatment in the primary dentition and in adults. This systematic review reinforces the need for future dinical research of high quality, incorporating modern concepts of dinical performance and evaluation to assess dental caries control using professional fluoride varnish.

Adolescent↗
PubMed1999

Fluoride concentration in whole saliva and separate gland secretions after topical treatment with three different fluoride varnishes.

Fluoride concentration in whole saliva and in separate gland secretions was determined after a single application of each of 3 different fluoride varnishes with contrasting levels of fluoride in a randomized crossover design. The study group comprised 8 healthy schoolchildren aged 10-12 years treated with A: Bifluorid 12 (6% F); B: Duraphat (2.26% F); and C: Fluor Protector (0.1% F). Unstimulated and stimulated whole saliva, as well as stimulated parotid and submandibular-sublingual saliva, were collected at baseline and 1, 6, 12, and 24h after the varnish treatments. The fluoride concentrations were determined with an ion-selective electrode. Time- and dose-dependent concentration curves were obtained in all the collected secretions, A > B > C. In whole saliva, the fluoride levels were significantly elevated (P<0.01) 1 h after the A and B varnish applications compared with baseline, while the increase was insignificant for varnish C. Similar patterns were unveiled in the parotid and submandibular-sublingual secretions, although the increase in fluoride concentration was modest. The elevated levels did not exceed 6 h for any of the varnish tested. The results of this study suggest a correlation between the concentration of fluoride of the varnish and fluoride levels obtained in saliva after application.

Calcium Fluoride↗
PubMed1990

The use of 'Fluor Protector', a fluoride varnish, as a caries prevention method under orthodontic molar bands.

The aim of this study was to determine whether Fluor Protector, a fluoride varnish, applied to molars before orthodontic banding could prevent white spot formation. In the in vitro study 93 human premolars were used, divided in five different groups, representing different clinical situations. Each tooth was sliced in half, one as a control and the other as a test specimen. All tooth halves were stored in a demineralizing solution, in an attempt to induce white spot formation. In the in vivo study 104 molars (52 controls and 52 tests) of 28 orthodontic patients were involved. The 'split-mouth technique' was used. After evaluation of the results of both studies, it is evident that Fluor Protector is very effective in the prevention of white spot formation under molar bands.

Dental Caries↗
PubMed2000

Retrograde seal in ultrasonically prepared canals.

The sealing ability of various retrofilling materials was compared. The root canals of 85 single-rooted teeth were cleansed and obturated with gutta-percha without sealer using lateral condensation. The apical 3 mm of the roots were resected and divided into positive control, negative control, and five experimental groups. The experimental teeth received root-end cavity preparation to 3 mm depth using an ultrasonic retroprep tip. The retrocavities were dried and divided into five groups to receive the following materials: amalgam with varnish, amalgam with Clearfil Liner Bond II, thermoplasticized gutta-percha (TGP) with sealer, Ketac-fil, and Super-EBA. After immersion in India ink for 7 days, the roots were demineralized, cleared, and evaluated for dye leakage under a stereomicroscope. Statistical analysis showed that Super-EBA, Ketac-fil, and TGP with sealer demonstrated less leakage than amalgam with varnish and amalgam with Clearfil Liner Bond II (p < 0.05). Super-EBA also leaked significantly less than Ketac-fil or TGP sealer (p < 0.05). No significant difference was found between Ketac-fil and TGP or between the two groups filled with amalgam (p > 0.05).

Dental Amalgam↗
PubMed1980

Fluoride uptake by cavity walls following application of Duraphat around amalgam restorations.

This study aimed to assess possible fluoride uptake by cavity walls following a single application of Duraphat around class V or I amalgam restorations which were inserted in seventeen human premolars in vitro and in vivo. Six cavities were lined with one layer of Copalite before insertion of the restorations. After a week in vivo and 12--24 h in vitro, 200--300 micrometers thick longitudinal sections passing through the cavities were prepared. By electron probe microanalysis F concentrations ranging from 2000 to 6000 ppm were measured near the surface of the cavity walls. Copalite seemed to inhibit F uptake. The study indicates that F ions released from the Duraphat varnish have been taken up by the cavity walls. Such uptake may influence development of secondary caries (wall lesions) in connection with amalgam restorations.

Child↗
PubMed1990

Long-term use of dentine adhesive as an interfacial sealer under Class II amalgam restorations.

An in vitro study was carried out to evaluate the long-term sealing properties of a light-cured dentine adhesive in Class II amalgam restorations. The restorations were subjected to repeated vertical occlusal loads and a number of thermocycling procedures. The results demonstrated significant advantages of using a dentine adhesive as an interfacial sealer in order to reduce microleakage, compared to a conventional Copal varnish.

Composite Resins↗
PubMed1996

Secondary caries formation in vitro around glass ionomer-lined amalgam and composite restorations.

The aim of this in vitro secondary caries study was to examine the glass-ionomer liner's effect on wall-lesion inhibition when a conventional and a light-cured glass ionomer liner was placed under amalgam and composite resin restorations. Class V preparations in extracted upper premolars were used and ten restorations were used for each of the following groups: (i) two layers of copal varnish and amalgam; (ii) conventional glass-ionomer and amalgam; (iii) light-cured glass-ionomer and amalgam; (iv) bonding agent and light-cured composite resin; (v) conventional glass-ionomer, bonding agent and light-cured composite resin; (vi) light-cured glass-ionomer, extended 0.3 mm short of the enamel margin bonding agent and light-cured composite resin; and (vii) light-cured glass-ionomer, extended 1 mm short of the enamel margin, bonding agent and light-cured composite resin. The teeth were thermocycled and artificial caries were created using an acid-gel. The results of this study showed that artificial recurrent caries can be reduced significantly (P < 0.05) with a glass-ionomer liner under amalgam restorations. The results also showed that when the light-cured glass-ionomer liner was placed 0.3 mm from the cavosurface margin under composite resin restoration, the artificial recurrent caries reduced significantly (P < 0.05).

Acids↗
PubMed1980

Stump the experts.

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Dermatitis, Contact↗
PubMed2000

Candida albicans colonization of surface-sealed interim soft liners.

PURPOSE: This in-vivo investigation evaluated the effect of 2 denture sealer agents on the microbial colonization of a newly placed soft interim denture liner during a period of 14 days. MATERIALS AND METHODS: An interim soft denture liner (Coe-Soft; GC America, Alsip, IL) was coated with 2 different denture surface sealants (Palaseal [Heraeus Kulzer, Irvine, CA] and Mono-Poly [Plastodent, New York, NY]). Three rectangular wells of 1 cm wide x 2 cm long x 2 mm deep were placed in the intaglio of 10 maxillary complete dentures and filled with the soft liner material. The soft liner surface was treated with Palaseal (first well) and Mono-Poly (second well), and the unsealed (third well) was used as a control. These were exposed to the oral cavity for 14 days. The effect the sealant had in the prevention of Candidal colonization in vivo of the soft liner material was evaluated. Microbiological specimens were recovered from all samples and cultivated. Microbiological data from the control and 2-test samples in each denture were tabulated, and statistical analyses were performed. RESULTS: This investigation showed clear differences (p <.001) between the sealed and unsealed soft liners. The sealed material showed significantly less colonization by yeast and bacteria. Intercomparison of the surface denture sealers, Palaseal versus Mono-Poly, showed no statistically significant differences (p < .005) in total yeast or bacterial colonization. CONCLUSION: Coating of Coe-Soft denture liner with either Palaseal or Mono-Poly significantly decreased yeast and bacterial colonization. .

Adult↗