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PubMed2005

Discoloration of restorative materials after bleaching application.

OBJECTIVE: The esthetic application of bleaching materials has gained popularity, with consequences for teeth and restorative materials. The aim of this investigation was to evaluate the influence of different bleaching agents with varying peroxide concentrations on restorative materials. METHOD AND MATERIALS: The color behavior, Vickers hardness, and surface roughness were determined on different restorative materials and bovine enamel. Cylindric samples of two fine hybrid composites, one microfilled composite, one compomer, and one ormocer were bleached for two 2-hour periods with three commercial and three experimental bleaching agents with varying peroxide concentrations. The properties were determined before and after bleaching. As a control, all materials were investigated without bleaching after a 14-day storage. RESULTS: The restorative materials showed maximum changes in Vickers hardness of 44, maximum changes in surface roughness of between 0.2 and 0.7 microm, and a maximum discoloration of deltaE = 6.8. A statistically significant deterioration of hardness, combined with the highest discoloration, was found for the microfilled composite and the compomer. Different bleaching systems showed varying effects on surface roughness. CONCLUSION: Bleaching resulted in a deterioration of the restorative materials, indicated by a decrease of hardness and an increase in surface roughness. Generally, bovine enamel showed significantly higher discoloration compared to the restorative materials.

Animals↗
PubMedDate not supplied

Influence of dietary solvents on strength of nanofill and ormocer composites.

The objective of this study was to determine the influence of dietary solvents on the shear punch strength of nanofill (Filtek Supreme [FS], 3M-ESPE) and ormocer (Admira [AM], Voco) composites. The strength of these materials was also compared to a minifill composite (Z250 [ZT], 3M-ESPE), a compomer (F2000 [FT], 3M-ESPE) and a highly viscous glass ionomer cement (Ketac Molar Quick [KM], 3M-ESPE). Thirty-two specimens (8.7 mm diameter and 1-mm thick) of each material were made, randomly divided into four groups of eight and conditioned for one week as follows-Group 1 (control): distilled water at 37 degrees C; Group 2: 0.02M citric acid at 37 degrees C; Group 3: 50% ethanol-water solution at 37 degrees C and Group 4: heptane at 37 degrees C. After conditioning, the specimens were restrained with a torque of 2.5 Nm and subjected to shear punch strength testing using a 2-mm diameter punch at a crosshead speed of 0.5 mm/minute. The shear punch strength of the specimens was computed and data subjected to ANOVA/Scheffe's tests at significance level 0.05. With the exception of AM, the strength of all materials was not significantly influenced by dietary solvents. For AM, conditioning in heptane resulted in significantly higher shear strength values. The strength of the nanofill and ormocer composites was lower than the minifill composite but higher than the compomer and highly viscous glass ionomer cement investigated.

Analysis of Variance↗
PubMed2005

Longevity of bonds made by composite and polyacid-modified resins to dentin using a dual-cured adhesive system.

PURPOSE: To evaluate the microtensile bond strengths (MTBS) of a dual-cured dentin adhesive bonded to dentin using a light-cured resin-based composite (composite) or a polyacid-modified resin-based composite (compomer), and to investigate the effect of water aging on the bond strengths of these systems. METHODS: Flat dentin surfaces prepared from extracted human third molars were bonded with Prime&Bond NT Dual-Cured version (PBNT). Resin build-up crowns were constructed incrementally with two different materials: a composite (Z250) or a compomer (Dyract AP). When Dyract AP was used as the restorative material, half of the specimens were etched with 36% phosphoric acid, and the other half of the specimens were not etched. After storage in water for 24 hours or for 6 months, the teeth were sectioned to obtain bonded 1.3 mm2 beams containing the bonded interface. Each beam was tested in tension in an Instron machine at 0.5 mm/minute. Results were analyzed by multiple ANOVA and Student-Newman-Keuls multiple comparison tests. RESULTS: The group PBNT/Dyract AP bonded to acid-etched dentin showed the highest bond strength, in the 24-hour evaluation. Bond strength values decreased significantly after aging. The groups treated with PBNT in light-cured, dual-cured and self-cured modes performed equally well in the 24-hour evaluation. After 6 months of water aging, bond-strengths of the light-cured groups remained stable. By contrast, decreases in the bond strengths of the self-cured groups were observed.

Acid Etching, Dental↗
PubMed2005

The weight change of various light-cured restorative materials stored in water.

This study investigated weight changes of seven different light-cured composite restorative materials, one polyacid glass ionomer compomer, and one light-cured glass-ionomer cement following short-term and long-term storage in water. Two packable composites, three universal (hybrid) composites, one microglass composite, one polyacid glass ionomer resin composite (compomer), one microhybrid low-viscosity (flowable) composite, and one light cured glass ionomer composite cement were evaluated in this study. The weight changes of these specimens were measured daily (short-term storage), and they were measured after six weeks (long-term storage) using an electronic analytical balance. A significant difference was found in Ionoliner, Dyract AP, Opticor flow, Charisma, and Solitare 2, but no significant difference was found in the others (Filtek Z 250, Filtek P60, TPH Spectrum, and Valux Plus). Weight change showed a tendency to increase with the time of water storage. The greatest weight change occurred in light-cured glass ionomer composite cement (Ionoliner), which is followed in order by the weight changes in Dyract AP, Opticor Flow, Charisma, Solitare 2, Filtek Z250, Filtek P60, TPH Spectrum; Valux Plus had the least amount of change.

Absorption↗
PubMed2005

Colour stability of tooth-coloured restorative materials.

The colour stability of the surface and in-depth (2 mm) layer of two resin composites, a laboratory second-generation resin composite and a compomer were evaluated after 24 and 360 hours of water aging under dark and UV light conditions. The influence of various polymerization techniques on color changes was also evaluated. Color differences (deltaE*) showed higher color changes under UV light exposure than under dark storage, both at 24- and 360-hour evaluations. Color changes were statistically higher at the 360-hour assessment, in both conditions of maintenance. Compomer was the least color stable of the materials tested. Additional polymerization significantly decreased the colour change of both composite resins.

Acrylic Resins↗
PubMedDate not supplied

Effects of pH on the microhardness of resin-based restorative materials.

This study determined the effect of pH on the microhardness of commonly used resin-based restorative materials which included a resin composite (Esthet-X, Dentsply), a new generation compomer (Dyract Extra, Dentsply) and a giomer (Beautifil, Shofu). Fifty-four specimens (3-mm wide x 3-mm long x 2-mm deep) were made for each material. The specimens were divided into six equal groups and conditioned in the following solutions at 37 degrees C for one week: 0.3% citric acid at pH 2.5, sodium hydroxide-buffered citric acid at pH 3, 4, 5, 6 and 7. After conditioning, the specimens were subjected to hardness testing using a digital microhardness tester (load 500gf; dwell time 15 seconds). Data was analyzed using one-way ANOVA and Scheffe's test at a significance level of 0.05. The effects of pH on the microhardness of resin-based restoratives were material dependent. The compomer and giomer materials were more affected by acids of low pH than the composite material that was evaluated.

Acrylic Resins↗
PubMed2005

The color differences between different thicknesses of resin veneered over amalgam.

STATEMENT OF PROBLEM: Composites and compomers are popular in dental practice. However, little is known about their esthetic appearance as veneering restorative materials over amalgam restorations. PURPOSE: This in vitro study was designed to assess the color differences of composite and compomer restorative materials, placed in thicknesses of 1 mm and 2 mm over amalgam. MATERIAL AND METHODS: Thirty six cylindrical Teflon molds were filled with amalgam (13 mm diameter, 2 mm thickness) and stored at 37 degrees C and 100% relative humidity for 7 days. Nine veneers (for each thickness of 1 and 2 mm) were fabricated from four types of tooth-colored restorative material, Dyract AP (DYR), Compoglass F (COMP), Herculite XRV (XRV), and Vitalecense (VIT), over amalgam specimens using Teflon-split molds and following the manufacturers' instructions. A spectrophotometer was used to measure the color difference DeltaE* between the two thicknesses. RESULTS: Color difference DeltaE* values for 1 mm thickness veneers [XRV (2.52), Comp (5.46), VIT (6.73), and DYR (6.88)] were statistically significantly higher than the 2 mm thickness [XRV (1.32), Comp (3.24), VIT (4.89), and DYR (4.83)]. Although the XRV material had the lowest DeltaE* values, no statistically significant difference was found between the two thicknesses. The color measurements at L*, a*, and b* showed most materials became darker in color at either thickness. CONCLUSION: The thicker veneer specimens were found to be closer in color to the controls than the thinner specimens. Only XRV had color differences (DeltaE*) small enough to be considered clinically acceptable (2.52 and 1.32 at 1 mm and 2 mm, respectively). CLINICAL IMPLICATIONS: In this in vitro study the color of XRV was affected the least when veneered on amalgam. Opaquers may be needed to be used with thinner veneers to minimize the effect of amalgam background.

Analysis of Variance↗
PubMed1995

Marginal sealing ability of three cervical restorative systems.

The purpose of this in vitro study was to evaluate the enamel and dentinal marginal sealing ability of three different cervical restorative systems. Class V preparations were made at the cementoenamel junction of 36 freshly extracted premolars. The teeth were randomly divided into three groups of 12 and restored with either a polyacid-modified resin composite ("compomer"), resin composite, or resin-modified glass-ionomer cement. The restored teeth were stored in saline at 37 degrees C for 1 week, thermally stressed for 500 cycles, and subjected to dye penetration testing. The results showed that there was no significant difference in dentinal margin sealing ability among the three materials evaluated. When the margins were in enamel, the resin composite restorations had significantly less leakage than did compomer or resin-modified glass-ionomer cement restorations. The marginal sealing ability of all three materials was significantly poorer in dentin than in enamel.

Analysis of Variance↗
PubMed1996

Clinical evaluation of Dyract in primary molars: 1-year results.

PURPOSE: To evaluate the 1-year clinical performance of Dyract in primary molars. MATERIALS AND METHODS: 55 children (aged 4-9 years) received 1-3 restorations (n = 91) utilizing Dyract, a new restorative material combining properties of both glass ionomers and composites. RESULTS: The so-called compomer material showed good handling characteristics and a survival rate of 97% after 1 year. Nevertheless, the material demonstrated an average wear of 190 microns during 1 year, with 67% of the restorations having occlusal wear of less than 200 microns. The combination of a low failure rate and the ease of application makes the compomer material very suitable for application in the primary dentition.

Child↗
PubMed1997

Effect of cavity design on microleakage of resin-modified glass ionomer restorations.

PURPOSE: To investigate cavity sealing with resin-modified glass ionomer cements (RGIC) and a compomer relative to the design of Class V cavities crossing the CEJ. MATERIALS AND METHODS: Three types of cavities, 6 x 3 x 1.5 mm, were prepared buccally in human molars. Type 1: semicircular with 90 degrees cavo-surface angle; Type 2: as type 1, but with bevelled enamel margin; Type 3: V-shaped. The cavities were restored with the compomer Dyract (DYR), with one of the RGIC, Fuji II LC (FUJ), Photac-Fil (PHF) or Vitremer (VIT), or with the bonded resin composite system Gluma-CPS/Pekafill (GLP) as a reference. Six restorations in each group were finished immediately after curing and thermocycled 1500 between 5 degrees C and 55 degrees C. For Type 1 restorations, another set of six samples was stored in 23 degrees C water for 24 hours. After thermocycling and water storage, respectively, the specimens were immersed in 0.1% fuchsin. Two sections were made through the restoration to register microleakage on the four surfaces produced as depth of dye penetration coronally and apically by scores 0 (no) to 4 (beyond deepest part of cavity). The results were statistically analyzed by cavity type, site, and restorative material using Kruskal-Wallis ANOVA and Wilcoxon's two sample test at P = 0.05. RESULTS: When compared with water storage, thermocycling had no effect on dye penetration with FUJ and PHF, yet more pronounced microleakage at the enamel site was noted with DYR and VIT, and apically with DYR and GLP. Type 1 restorations leaked more than type 2 and 3 cavities for FUJ, VIT and GLP.

Analysis of Variance↗
PubMed1997

The marginal seal of various restorative materials in primary molars.

The use of resin composite restorations in posterior teeth has become an accepted clinical procedure. Microleakage at the posterior composite/tooth interface is a major problem. The in vitro quality of the marginal seal was tested in eighty teeth extracted for orthodontic reasons using a glass-ionomer cement reinforced with amalgam, two light self-curing glass-ionomer cements and a compomer. All the teeth were subjected to thermocycling to simulate clinical situation. Compomers showed the best mechanical and esthetic properties combined with a good marginal seal.

Compomers↗
PubMed2002

Enzymatic responses of human deciduous pulpal fibroblasts to dental restorative materials.

The purpose of this study was to evaluate the responses of succinic dehydrogenase (SDH) and alkaline phosphatase (ALP) activities of human deciduous teeth pulpal fibroblasts (HDPF) to dental restorative materials. Tested materials included Z100 (3M), Dyract (Dentsply), FujiII (GC), and FujiIILC (GC). IRM (Dentsply) and culture medium (MD) alone were used as positive and negative controls, respectively. Specimens 6 mm (diameter) x 3 mm were prepared in accordance with manufacturers' instructions. For light-cured materials, specimens were light cured for 40 s on both sides under a celluloid strip. For chemical-cured materials, specimens were allowed to set at room temperature for 15 min. The specimens were immersed in 1 mL of culture medium without serum for 24 h at room temperature. The extracts were filtered through 0.22-mm filters. HDPF (10,000 cells/well) was incubated with 100 microL of extract and 20 % FBS in a 96-well plate for 24 h in a 37 degrees, 5 % CO(2) incubator. Six wells per material were prepared. Optical density (OD) of SDH and ALP of HDPF were measured by a spectrophotometer. The means were analyzed by ANOVA and then a Duncan Test. The ranking of OD of SDH was IRM < FujiIILC < FujiII = Z100 < Dyract < MD (p < 0.05). The ranking of OD of ALP was IRM < Z100 = Dyract < FujiII < FujiIILC < MD (p < 0.05). The result showed that all of the tested restorative materials were cytotoxic to human deciduous pulpal fibroblasts. The cytotoxicity of resin-modified glass ionomer cements (FujiIILC) was stronger than that of traditional glass ionomer cements (FujiII) and composite resin (Z100), and that of compomer (Dyract) was the weakest. On the contrary, ALP activities of resin-modified glass ionomer cements (FujiIILC) and composite resin (Z100) were higher than those of traditional glass ionomer cements (FujiII), while those of compomer (Dyract) were the lowest. It is concluded that, in this study, FujiIILC was the most cytotoxic material and the least inhibitive of ALP activities, Dyract was the weakest cytotoxic material and had the highest inhibition of ALP activities. The rankings of the MTT assay and the ALP assay were not consistent.

Alkaline Phosphatase↗
PubMed2007

Changes in scattering and absorption properties of esthetic filling materials after aging.

OBJECTIVES: Assuming that color changes after aging are related to changes in translucency of materials, the purpose of the present study was to determine the correlation between the changes in color and the changes in scattering and absorption properties after accelerated aging with representative dental esthetic restorative materials: glass ionomer, resin-modified glass ionomer, compomer, and resin composite. METHODS: Color was measured according to the CIELAB color scale in the transmittance and reflectance modes and used to calculate changes in color (deltaE*(ab)), color coordinates (deltaL*, delta a*, and delta b*), translucency parameter (deltaTP), scattering coefficient (deltaS), absorption coefficient (deltaK), and light reflectivity (deltaRI) after accelerated aging. Simple correlations between each pair of the changes in optical values were calculated, and multiple regression analysis was used to determine the parameters influencing the changes in color and color coordinates (p = 0.05). RESULTS: In the resin composite and compomer, deltaS, deltaK, and deltaRI values were approximately zero, whereas deltaS was as high as 8.9 in the glass ionomer. For most comparisons, correlation coefficient (r) was between 0.700 and 0.997. DeltaL* was found to have a major influence on color changes, and deltaS, deltaTP, and deltaRI influenced deltaL*. Therefore, changes in scattering and absorption properties, after aging, were closely correlated with changes in color and color coordinates, especially in glass ionomer-based filling materials.

Acrylic Resins↗
PubMed2006

Review on fluoride-releasing restorative materials--fluoride release and uptake characteristics, antibacterial activity and influence on caries formation.

OBJECTIVES: The purpose of this article was to review the fluoride release and recharge capabilities, and antibacterial properties, of fluoride-releasing dental restoratives, and discuss the current status concerning the prevention or inhibition of caries development and progression. METHODS: Information from original scientific full papers or reviews listed in PubMed (search term: fluoride release AND (restorative OR glass-ionomer OR compomer OR polyacid-modified composite resin OR composite OR amalgam)), published from 1980 to 2004, was included in the review. Papers dealing with endodontic or orthodontic topics were not taken into consideration. Clinical studies concerning secondary caries development were only included when performed in split-mouth design with an observation period of at least three years. RESULTS: Fluoride-containing dental materials show clear differences in the fluoride release and uptake characteristics. Short- and long-term fluoride releases from restoratives are related to their matrices, setting mechanisms and fluoride content and depend on several environmental conditions. Fluoride-releasing materials may act as a fluoride reservoir and may increase the fluoride level in saliva, plaque and dental hard tissues. However, clinical studies exhibited conflicting data as to whether or not these materials significantly prevent or inhibit secondary caries and affect the growth of caries-associated bacteria compared to non-fluoridated restoratives. SIGNIFICANCE: Fluoride release and uptake characteristics depend on the matrices, fillers and fluoride content as well as on the setting mechanisms and environmental conditions of the restoratives. Fluoride-releasing materials, predominantly glass-ionomers and compomers, did show cariostatic properties and may affect bacterial metabolism under simulated cariogenic conditions in vitro. However, it is not proven by prospective clinical studies whether the incidence of secondary caries can be significantly reduced by the fluoride release of restorative materials.

Cariostatic Agents↗
PubMed2001

Suitability of a shear punch test for dental restorative materials.

OBJECTIVE: The aim of the study was to evaluate the suitability of a shear punch test for determining the mechanical properties of dental restorative materials. The method was evaluated by measuring and comparing the shear punch strength of seven different restorative materials, that is amalgam, composite resin, compomer, composite containing pre-reacted glass ionomer filler, resin modified glass ionomer, glass ionomer and polycarboxylate cement. METHOD: The effects of specimen restraining conditions, specimen thickness and test speed on the shear punch strength were evaluated using polycarboxylate cement and two different equipment set-ups. Using the preferred testing regime as determined in the preliminary experiments, the shear punch strength of seven different materials were measured and compared. Twenty disc specimens, 0.5mm thick and 10mm diameter, were prepared for each material, restrained within the test equipment and tested at a speed of 1.0mm/min. RESULTS: The shear punch strength increased as the torque used for restraining a specimen was increased. There was no difference in shear punch strength for specimens of different thickness. The greatest shear punch strength was obtained at the test speed of 1.0mm/min. The shear punch strength values decreased in the order composite>composite containing pre-reacted glass ionomer filler>amalgam>compomer>resin-modified glass ionomer>glass ionomer>polycarboxylate. A difference in the shear punch strength for seven different kinds of restorative materials clearly emerged. Specimen fracture occurred by circumferential cracking for the shear-punch test. However, for some glass ionomer and amalgam specimens radial cracking was also observed. SIGNIFICANCE: This study suggests that the simple test described is suitable for standardization purposes.

Analysis of Variance↗
PubMed2005

UK dentists' attitudes and behaviour towards Atraumatic Restorative Treatment for primary teeth.

BACKGROUND: Atraumatic Restorative Treatment (ART) was introduced a decade ago as a minimal intervention treatment for caries in unindustrialised countries, but UK general dental practitioners (GDPs) may also be using this technique. OBJECTIVE: This study aimed to determine the materials and techniques used by a group of UK GDPs to treat caries in primary teeth. METHOD: A questionnaire, designed to determine GDPs' use of materials and techniques in the restoration of caries in primary teeth, was distributed to 600 GDPs in Scotland and England, with an explanatory letter and reply-paid envelope. The questionnaire included colour illustrations of two carious cavities in primary molar teeth and a request that respondents draw the cavity outline that they would use on the illustrations. The cavity outlines were assessed independently by two examiners. All other data were collated and analysed. RESULTS: 390 usable replies were received, a response rate of 65%. Of the respondents, 99% treated child patients and 42% of respondents were aware of ART. For treatment of a small Class II cavity, 37% drew a cavity outline without extension beyond removal of caries and a majority suggested use of an adhesive material (51% glass ionomer, 13% compomer). For cavity preparation, 47% of respondents used a drill, 10% an excavator and 41% used both. For treatment of a large occluso-lingual cavity, again most used an adhesive technique (44% glass ionomer, 12% compomer) for its restoration, while 50% used a drill, 7% an excavator and 42% used both for cavity preparation. CONCLUSION: Most respondents used adhesive materials for restoration of caries in primary molars, but, despite 42% of respondents stating that they were aware of the treatment, "true" ART was adopted by fewer than 10% of respondents.

Attitude of Health Personnel↗
PubMed2004

The effect of formocresol on bond strength of adhesive materials to primary dentine.

The aim of this study was to evaluate the effect of formalin cresol on bonding of two compomers (Prime & Bond and Dyract, Futurabond and Glasiosite to primary dentine. Eighteen non-carious primary mandibular molar teeth were used. The two materials were placed onto the tooth surfaces before being sheared with a knife-edged blade with a crosshead speed of 1 mm min(-1). Two randomly selected teeth from each group were evaluated by scanning electron microscopy (SEM). The statistical analysis (paired t-test and Student's t-test) revealed that shear bond strength was significantly higher in the formocresol-applied group than in the group that was not applied formocresol (P < 0.05), but there was no significant difference between the restorative materials. SEM analyses also supported the results obtained. In conclusion, if compomers are used after endodontic processes which require the application of formocresol in primary teeth, dentinal bonding would not be decreased, but on the contrary, increase.

Dentin↗
PubMed2004

Calculation of colour resulting from composite/compomer layering techniques.

This study determined the influence of optical properties of constituent layers on the colour of double-layer aesthetic filling materials. Multiple regression equations for the Commission Internationale de I'Eclairage (CIE) L*, a* and b* of layered materials were calculated from the optical values of the covering and underlying layers. Specimens (10 mm diameter, 1 mm thickness) of two light-cured resin composites and one compomer of seven to 11 shades were used. CIE L*, a* and b* values of each specimen were measured with a colour spectrophotometer backed by a standard white background. The scattering coefficient (S), absorption coefficient (K), contrast ratio (C) and translucency parameter (T) were calculated. Double-layered specimens were formed in optical contact by joining two different shades from the same material, or resin composite as covering with a compomer underlying layer. Each of the L*, a* and b* of layered material was used as a dependent variable, and 14 optical values of underlying and covering layers were used as independent variables in forward regression analysis (P = 0.01). CIE L* after layering had a positive correlation with S of covering layer (correlation coefficient; beta = 0.79-0.91, P < 0.01) and a correlation with L* of underlying layer (beta = 0.14-0.16). CIE a* after layering had a correlation with a* of covering layer (beta = 0.83-0.94) and a correlation with a* of underlying layer (beta = 0.30-0.56). CIE b* after layering had a correlation with b* of covering layer (beta = 0.77-0.90) and a correlation with T of covering layer (beta = 0.40-0.59). The layered colour of these materials can be predicted by the derived regression equations within the limitations of this study. CIE L*, a* and b* values of double-layer material are mainly influenced by S, CIE a* and b* of covering layer, respectively.

Colorimetry↗