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PubMedDate not supplied

Influence of delayed placement of composites over cured adhesives on dentin bond strength of single-application self-etch systems.

This study examined the relationship between delay in composite placement over cured adhesives and the dentin bond strength of several single-application self-etch adhesive systems. The adhesive system/resin composite combinations used were: Adper Prompt L-Pop/Filtek Z250 (AP), AQ Bond Plus/Metafil C (AQ), Fluoro Bond Shake One/Beautifil (FB), G-Bond/Solare (GB), One-Up Bond F Plus/Palfique Estelite (OF), Xeno IICF Bond/Xeno CF (XE). Bovine mandibular incisors were mounted in self-curing resin and wet ground with #600 SiC to expose labial dentin. The adhesives were applied according to each manufacturer's instructions, and resin pastes were condensed into a mold (ø4x2 mm) immediately, and 1, 2, 5 and 10 minutes after light irradiation of the adhesives. Ten samples per test group were stored in 37 degrees C water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/minute. One-way ANOVA followed by Tukey's HSD test (alpha = 0.05) was done. SEM observations of the dentin surface after the tests were also conducted. Dentin bond strength ranged from 9.5 +/- 2.2 to 14.0 +/- 2.4 MPa for AP, 7.3 +/- 2.2 to 12.2 +/- 3.1 MPa for AQ, 10.0 +/- 3.5 to 16.3 +/- 2.4 MPa for FB, 11.4 +/- 1.5 to 16.3 +/- 1.2 MPa for GB, 14.2 +/- 3.4 to 15.1 +/- 3.0 MPa for OF and 11.5 +/- 2.4 to 15.9 +/- 2.2 MPa for XE. Except for OF, no significant differences were found among the 2 to 10 minute delayed placement groups for the systems used. Significant lower bond strengths were obtained for the immediate placement groups except for OF. From SEM observations, cohesive failure of the dentin surface was more pronounced with the longer delay in placement. The data suggest that delayed composite placement over the cured adhesives are suggested for optimum dentin bond strength of single-application self-etch adhesive systems.

Acid Etching, Dental↗
PubMedDate not supplied

Use of two surface analyzers to evaluate the surface roughness of four esthetic restorative materials after polishing.

This study had two aims: determine how well four esthetic restorative materials lent themselves to polishing and compare the results obtained using two different techniques for evaluating surface roughness. The four materials used were two composites modified by the addition of resin, Dyract AP (Dentsply) and Dyract Flow (Dentsply); one composite designed for posterior restorations, SureFil (Dentsply) and one universal micromatrix composite, Esthet-X (Dentsply). Five test pieces were made with each product by inserting the material into cylindrical molds and polymerizing it layer by layer. A single operator polished the specimens on the same day using the Enhance system (Dentsply) and two aluminum oxide pastes. The surfaces were studied successively by means of two surface analyzers: a high-resolution optical profilometer (Nanosurf 488, SAS Technology) and a mechanical profilometer (Mitutoyo Surftest-SV 402). These measurements gave the mean roughness of the surface (Ra). Ten zones were examined for each specimen, and the specimens were observed under an optical microscope (PMG3 inverted metallographic microscope) at 50x magnification. The qualitative and quantitative analyses of the results showed good surface states for all materials. However, the composites based on nano- and micro-filler technology gave the smoothest surfaces after polishing. A comparison of the values obtained with each method of observation showed that mechanical profilometry tended to show roughness caused by polishing, while optical profilometry brought out roughness due to the structure of the material itself.

Aluminum Oxide↗
PubMedDate not supplied

SEM evaluation of a non-rinse conditioner and a self-etching adhesive regarding enamel penetration.

This study evaluated the effect of a non-rinse conditioner (NRC) associated with two adhesive systems, Prime & Bond NT and Prime & Bond 2.1. The study also evaluated a self-etching adhesive, comparing it with the 37% phosphoric acid effects related to the regularity and infiltration depth of adhesives in human tooth enamel via observation using Scanning Electronic Microscopy (SEM). Fifteen third molars were longitudinally sectioned into four parts by means of a mesio-distal cut and facio-lingual cut. All pieces were flattened with silicon carbide paper, randomly separated and divided into five groups where the enamel surfaces were treated with different materials according to the manufacturers' instructions as follows: Group 1-Prime & Bond NT (Dentsply); Group 2-37% phosphoric acid + Prime & Bond NT; Group 3-Non-Rinse Conditioner (Dentsply) + Prime & Bond NT; Group 4-NRC + Prime & Bond 2.1 (Dentsply); Group 5-Prompt L-Pop (3M ESPE). All teeth were covered with Dyract AP (Dentsply). Specimens were decalcified, metalized and the inner portions of Dyract were observed in SEM and evaluated by calibrated examiners to evaluate resin penetration on enamel. Resin penetration was ranked from 0 = no penetration, to 3 = maximum penetration. The Kruskal-Wallis and Mann-Whitney U tests (p<0.05) showed only three statistically homogeneous groups: {1}, {2,3} and {4,5}. The authors concluded that Prime & Bond NT showed the lowest penetration, NRC showed similar effects compared to phosphoric acid when associated with Prime & Bond NT, and concluded that Prompt L-Pop showed similar effects to NRC, which was associated with Prime & Bond 2.1.

Acetone↗
PubMed1995

Resin-modified glass ionomer cements: fluoride release and uptake.

The aim was to study the short- and long-term fluoride release from resin-modified glass ionomer cements (GIC). The aim was also to determine the effect of fluoride treatment of 9-month-old specimens, consistency of the mix, and pH of the environment on the fluoride release. GIC test specimens were continually exposed to running water, and the fluoride release was measured periodically by storing the specimens in 5 ml deionized water for 1 week and measuring the fluoride content of the solution. After 24 h, 1 month, 9 months, and 11 months in running water four of the six resin-modified GICs released as much as or more fluoride than the auto-curing GIC tested for comparison. Fluoride treatment after 9 months also increased the fluoride release of these four brands, as was the case with the conventional GIC. At 24 h and 1 month two of the resin-modified GICs released smaller amounts of fluoride than the other materials, and the fluoride treatment used on those had no or only a minimal effect. Thin consistency of a mix resulted in higher fluoride release for one resin-modified material than a thick mix. Low pH increased the fluoride release for all materials.

Acrylic Resins↗
PubMed1995

Strength and setting behavior of resin-modified glass ionomer cements.

Diametral tensile strength (DTS), fracture strength, and Vickers microhardness were tested in three resin-modified glass ionomer cements (GICs), one chemically set GIC, and one dental composite. For the DTS studies test discs were immersed in deionized water at 37 degrees C for 10 min, 1 day, and 28 days, respectively. Cured discs were also implanted in back muscles of rats for 28 days before testing. The effects of light irradiation time and delayed curing on the DTS of the cements were also studied. Significantly higher strength was observed in the resin-modified GICs in comparison with the chemically set GIC at all observation period. K71 showed the highest strength among the GICs. No strength reductions were detected after 28 days for the specimens in vivo. An illumination time of 20 sec was enough to obtain final strength in the PFA and K71 specimens, and 40 sec was needed in the VI specimens. The strength of the resin-modified GICs when light-cured was significantly higher than when the same cements were allowed to set without irradiation. The microhardness of the light-cured GICs was similar to that of the dental composite. Considering the improved fracture strength and surface hardness, it was concluded that the resin-modified GICs present an interesting material for further development.

Acrylic Resins↗
PubMed1999

Resin content in cement liquids of resin-modified glass ionomers.

Qualitative and quantitative analyses were conducted on four kinds of resin-modified glass ionomer (RMGI) cement liquids, LC, LC II, LC III (hereinafter referred to as LCs) and VM, using HPLC and laser Raman spectroscopic methods. HPLC revealed that among the RMGI liquids LCs contain 31-32% HEMA (2-Hydroxyethyl methacrylate), and VM contains 18% of the same. The composition of RMGI cement liquids varied significantly between manufacturers. In Raman spectroscopic analyses, the spectra of liquids of various ratios of polyacrylic acid and HEMA were measured, and calculations were made on the peak intensity ratios of C=C stretch vibration to C=O stretch vibration, common in both HEMA and polyacrylic acid. The composition ratio of polycarboxylic acid to HEMA of commercial glass ionomer cements was assessed by the regression curve generated by a combination of peak intensity ratios and composition ratios. In addition, Raman spectroscopy was able to identity the differences in form of the methacryloyloxy group.

Carboxylic Acids↗
PubMed1999

Release and recharge of fluoride by restorative materials.

This study investigated the release and recharge of fluoride by restorative materials. Resin-modified glass ionomers (RGIs), polyacid-modified composite resins (PMCRs) and resin composite containing fluoride were used for comparison of fluoride release. Non-fluoride-releasing resin composite was used as a control. The amounts of fluoride release from RGIs and PMCRs remarkably increased in the citrate-phosphate acid buffer compared with distilled water. The amounts of fluoride recharged in RGIs increased with the concentration of NaF solution, but those of PMCRs exposed to all concentrations of NaF solutions were less than 1.5 ppm. Neither resin composite containing fluoride and non-fluoride-releasing resin composite gave any evidence of recharge. RGIs and PMCRs affected by acid buffer solution could not recharge much fluoride even if they were immersed in the 1000 ppmF NaF solution. The results suggested that the matrix of RGIs and PMCRs functioned as a reservoir of fluoride, but the functions were lost by acid attack.

Adsorption↗
PubMed2004

Bond strength of permanent cements in cementing cast to crown different core build-up materials.

The purpose of this laboratory investigation was to evaluate the bond strength of permanent cement (Duo-cement Kit, Meron, Durelon) to commonly used core build-up materials (President, Dyract AP, Ionofil, Vitremer). Sixty specimens (five of each product) were fabricated as a canine core build- up. Full crown castings were made to fit each core specimen. Full crown castings were cemented to core samples and stored at 37 degrees C and 100% humidity for 10 days. After storage, the bond strength was measured with a Haunsfield tensometer in tensile mode at a crosshead speed of 5 mm/min. Statistical evaluation was performed with univariate analysis of variance (P<0.001). The cement types affected the bond strength of full crown castings to core materials (F: 14.80; P<0.001). The interaction between the cement and core materials was significant (F: 3.69; P<0.01). According to the Duncan's test it was found that the values of Duo-cement were statistically different from the other cements.

Analysis of Variance↗
PubMed2004

An ultrastructural analysis of the prototype single-step adhesive applied on enamel and dentin surfaces.

A new type of self-etching agent, the single-step adhesive, was developed. The purpose of this study was to investigate the difference in the ultrastructural features of enamel and dentin surfaces following application of the prototype single-step adhesive (EXM618, 3M, MN, USA). Extracted caries-free human premolars were used in this study. Occlusal enamels of teeth--to be used as cut surface specimens--were removed perpendicular to the long axis of the specimens. The mesial and distal surfaces of these teeth, on the other hand, were used as uncut surface specimens in the test. In addition, Mega Bond (Kuraray Medical Inc., Tokyo, Japan) and Xeno CFII Bond (Dentsply Sankin, Tokyo, Japan) were used as controls. After covering half of the tooth surfaces with nail varnish (for control), the other half of each surface was treated with one of the three test adhesives--EXM618, Mega Bond, or Xeno CFII Bond--according to the manufacturer's recommendations. Conditioned enamel and dentin surfaces (i.e., decalcified depth and rugged surface) were observed with a scanning confocal laser microscope (SCLM 1100, Olympus, Tokyo, Japan; henceforth abbreviated as SCLM). Based on the findings of this study, the prototype single-step adhesive EXM618 appears to be suitable for use in dental clinics.

Acid Etching, Dental↗
PubMed2004

Effects of dietary acids on surface microhardness of various tooth-colored restoratives.

The aim of this in vitro study was to investigate if surface microhardness of Fuji IX GP, Vitremer, Dyract AP, and Prodigy is influenced by conditioning in aqueous solutions of lactic, orthophosphoric, citric, and acetic acids against bidistilled water (which was used as control). The pH values of acids used in this study were representative of dietary acids. All specimens were stored in bidistilled water for one week and then conditioned in the respective test solutions for another week. Citric (p<0.05) and acetic acids reduced, while lactic and orthophosphoric acids (p<0.05) increased the microhardness of both Fuji IX GP and Vitremer. On the other hand, microhardness of both Dyract AP and Prodigy was significantly reduced by all acidic media (p<0.05). The observed differences in the surface microhardness of various tooth-colored restorative materials conditioned in several media varied not only with the pH but also the nature of the acidic solution, and with the composition of the evaluated material.

Acetic Acid↗
PubMed2005

Fluoride release/uptake of glass-ionomer cements and polyacid-modified composite resins.

The aim of this study was to investigate the fluoride release and fluoride recharge behaviors of two conventional glass-ionomer cements (GICs) and two polyacid-modified composite resins (PMCRs) after exposure to mouthwash and toothpaste. Fluoride released from the materials was measured at 1st, 2nd, 3rd, 4th, 7th, 14th, 21st, and 28th days. At 28th day, the specimens were divided into three groups. Specimens in the control group were stored in deionized water. For the other two groups, the specimens were exposed to 0.05% NaF solution and fluoridated toothpaste for one month. After refluoridation, fluoride amount was measured at 30th, 31st, 32nd, 36th, 44th, 52nd, and 60th days. All materials released fluoride. The highest amount of fluoride was obtained during the first 24 hours, and there was a statistically significant difference between the amounts of fluoride released from GICs and PMCRs (p < 0.0001). After exposure to mouthwash and fluoridated toothpaste, all materials were recharged and continued releasing fluoride. While the amount of fluoride release from the materials increased after reflouridation, the increase was higher in GICs.

Cariostatic Agents↗
PubMed1997

Resin-ionomer and hybrid-ionomer cements: part II, human clinical and histologic wound healing responses in specific periodontal lesions.

Twenty-five subjects with a total of 50 subgingival restorations participated in this study. At the beginning of the investigation, nine teeth that were considered hopeless because of the extent of their pathology were selected for extraction to evaluate histologically the restorations and their effect on the adjacent tissues. The purpose of this article is to demonstrate the responses to the clinical applications as well as to the placement of resin-ionomers in subgingival lesions. Clinical and histologic evidence of epithelial and connective tissue adherence to resin-ionomer restorative materials was observed during the healing process.

Adult↗
PubMed1997

Clinical evaluation of hybrid ionomer restoratives in Class V abrasion lesions: two-year results.

Eighty Class V abrasion cavities were selected, and 20 cavities were restored with one of three resin-modified glass-ionomer materials (Fuji II LC, Photac-Fil, and Vitremer) or a polyacid-modified resin composite (Dyract). The restorations were clinically evaluated after 1 and 2 years with the US Public Health Service criteria. The results revealed a statistically significant difference in the percentage of restorations rated Alfa for color match at 2 years. No statistically significant difference was found in the percentage of alfa rating for anatomic form. Restorations of all materials showed some marginal discrepancies that were not statistically significant.

Compomers↗
PubMedDate not supplied

Fluoride release from some dental materials in different solutions.

Most of the data reported on release of fluoride from dental materials are based upon measurements made in deionized water and artificial saliva, which do not simulate the dynamics of caries development. So, the purpose of this study was to determine the level of fluoride released from different restorative materials in storage solutions, considering the caries process (pH-cycling). Six cylindrical samples of each material (Chelon-Fil, Dyract, Variglass, Vitremer, and Tetric) were prepared and suspended individually in 2.0 mL of each studied solution. The studied media were deionized water, artificial saliva, and solutions for pH-cycling (demineralizing solution--pH 4.3 and remineralizing solution--pH 7.0). All solutions were changed daily over 15 days. Fluoride release was determined after buffering the solutions with an equal volume of TISAB. The fluoride release was higher in pH-cycling than in the other solutions (P < 0.05), and changes of the rank order of fluoride release from the studied materials occurred when the different media were considered (P < 0.05). The data suggest that the comparison of fluoride released from dental materials is dependent on the medium used in the evaluation.

Acrylic Resins↗
PubMedDate not supplied

Bond strength of composite to enamel and dentin using Prime & Bond 2.1.

A laboratory study was conducted to determine the bond strength of composite to enamel and dentin using a one-component dental adhesive system (Prime & Bond 2.1) with three application regimens ranging from four to seven procedural steps. In addition, the effect of acid conditioning of dentin on bond strength was evaluated. Enamel bond strengths ranged from 29.2 to 29.8 MPa, and dentin bond strengths ranged from 18.6 to 21.3 MPa. Enamel bond strengths were significantly higher (P = 0.000) than dentin values. There was no significant difference (P > 0.05) among the bond strengths in either the enamel or dentin groups using the three application regimens. Nor did acid conditioning of dentin increase bond strengths (P = 0.683).

Acid Etching, Dental↗
PubMed1999

Volumetric microleakage assessment of glass-ionomer-resin composite hybrid materials.

OBJECTIVE: This study was intended to quantify the marginal leakage of three glass-ionomer-resin composite hybrid materials and compare it with the leakage exhibited by a glass-ionomer cement and a bonded resin composite system. METHOD AND MATERIALS: Standardized Class V cavities were prepared on root surfaces of 105 extracted human teeth, randomly assigned to five groups of 21 each, and restored with either Ketac-Fil Aplicap, Z100/Scotchbond Multi-Purpose Plus, Vitremer, Photac-Fil Aplicap, or Dyract. The teeth were thermally stressed for 500 cycles and stained with methylene blue. The microleakage was quantified spectrophotometrically, and the data were statistically analyzed with Friedman's test. RESULTS: There were no significant differences in microleakage among the five groups. Restorations of all tested materials showed some marginal leakage in Class V cavities. CONCLUSION: The microleakage performance of glass-ionomer-resin composite hybrid materials was similar to those of a conventional glass-ionomer and a bonded resin composite system.

Chi-Square Distribution↗
PubMedDate not supplied

Conservative interproximal box-only polyacid modified composite restorations in primary molars, twelve-month clinical results.

The treatment of proximal caries has changed during the last decade. The present study evaluates a recently developed material, applied in box-only preparations in primary molars. At the twelve-month evaluation of this clinical study, it became obvious that Dyract can be an alternative for Tytin in the primary dentition, though there is some change in color of the Dyract material. In time, the marginal adaptation of Dyract seems to improve. The preparation time for both materials is comparable. The total treatment time of box-only Dyract restorations (including an occlusal sealant), however, is longer compared to conventional class II Tytin restorations. Although in both groups radiolucencies were found at the baseline radiograph evaluation, no sign was found of secondary caries. One recurrent caries lesion was found adjacent to a Dyract restoration. It should be emphasized that one-year data do not indicate the longterm success of restorations.

Child↗
PubMed1998

Effect of cement space and delayed placement on the seating of crowns luted with Vitremer, Fuji Duet and Dyract Cem.

PURPOSE: To determine the effects of cement space and delayed placement on the post-cementation elevation of crowns luted with two resin-modified glass ionomer luting cements (Vitremer, Fuji Duet) and a self-curing polyacid-modified composite resin luting cement (Dyract Cem). MATERIALS AND METHODS: The investigation was conducted in two parts: (1) A loading apparatus was employed to simulate the seating of a crown on a die. Six dies, differing in the amount of cement space allowed from 6-52 microns, were used. The loading apparatus allowed for a test cement to be placed in the crown, and subsequent activation of the apparatus lead to seating of the die into the crown. After seating, post-cementation crown elevation was measured. The cements Phosphacap, Vitremer, Dyract Cem and Fuji Duet were used. Each cement was tested 10 times at each of the six cement spaces. The post-cementation crown elevation data was analyzed by one- and two-way ANOVA tests, and Tukey's HSD test. (2) The cements Vitremer, Fuji Duet and Dyract Cem, were tested in a similar fashion to Part 1, except activation of the loading apparatus was delayed. Three cement spaces (6, 29 and 52 microns) and three delay periods (60, 120 and 180 seconds) were investigated. Each cement was tested five times. The post-cementation crown elevation data was analyzed by one- and two-way ANOVA tests, and Tukey's HSD test. RESULTS: The amount of cement space provided and the cement used significantly affected post-cementation crown elevation (P = 0.001). Where cementation was delayed, post-cementation crown elevation was significantly affected by both the cement used and the amount of cement space provided (P = 0.001). Delayed placement of Dyract Cem had no significant effect on post-cementation crown elevation (P = 0.01). Post-cementation crown elevation when Vitremer was used was significantly affected by both the amount of cement space and delayed placement (P = 0.01). A 180-second delay in placement of Vitremer resulted in significantly worse post-cementation crown elevation (P = 0.01). Seating was not possible 120 seconds after Fuji Duet had been mixed.

Analysis of Variance↗