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PubMed1996

Resin-ionomer and hybrid-ionomer cements: Part I. Comparison of three materials for the treatment of subgingival root lesions.

The purpose of this study was to compare the characteristics of three different restorative materials for the treatment of subgingival root lesions. Eighteen recently extracted teeth were used to test the depth of cure and the surface characteristics of these products. Although none of the materials tested exhibited all of the author's ideal characteristics for a subgingival restoration, one restorative material displayed the most favorable result.

Biocompatible Materials↗
PubMed1997

Microleakage of glass ionomer cement composite resin and glass ionomer resin cement.

An in vitro dye leakage study was performed to compare the sealing ability of glass ionomer, composite resin and glass ionomer/resin cement when used as restorative materials for G.V. Black class V cavities. In this research, standard Class V cavities were prepared in sound premolar teeth extracted for orthodontic reasons. The cavities were randomly divided into 3 groups. After filling the cavities with glass ionomer cement, composite resin and light curing glass ionomer/resin cement, the specimens were immersed in silver nitrate solution. Marginal microleakage at the interface between the cavity wall and restoration was evaluated. The results were analyzed by using Kruskal-Wallis and Mann Whitney U tests. Result of this in vitro study indicate that composite resin and glass ionomer/resin cement provide a better seal than glass ionomer cement.

Aluminum Silicates↗
PubMed1997

Surface texture and enamel-restoration interface of glass ionomer restorations.

The aim of this study was to investigate the surface texture and enamel-restoration interface of Class II glass ionomer restorations in primary molars. A traditional (Chemfil II), a cermet (Chelon-Silver) cement and two light cured glass ionomer cements (Vitremer and Dyract) were used to restore the Class II cavities of 20 primary molars. The surface changes and enamel-restoration interface of restorative materials were evaluated by SEM, after a 12 month period. Microcracks and pores in surface were observed in all of the four different glass ionomer materials. Although, there was no marginal gap formation for Chemfil II, Chelon-Silver and Dyract samples, in 2 samples of Vitremer group gap formation was found with an ion-exchange layer. Also, in Dyract samples wear of restorations was considerable.

Cermet Cements↗
PubMedDate not supplied

Comparison of aesthetic properties of tooth-colored restorative materials.

The objective of this study was to compare the aesthetic properties of color and translucency of Vita shade-based tooth-colored restorative materials, including composite resins, a polyacid-modified composite resin, and resin-modified glass-ionomer cements via clinical discrimination by human evaluators. The hue/chroma, value, and translucency of the five different materials chosen to represent the range of commercially available tooth-colored restoratives were graded by 40 dental personnel against the body of their respective Vita shade tabs using a five-point scale (1 = very poor; 2 = poor; 3 = average; 4 = good; 5 = excellent). Results confirm the clinical observation that the hue/chroma, value, and translucency of the different materials evaluated do not match the Vita shade guide to which they are supposedly keyed. The aesthetic properties of hue/ chroma, value, and translucency for the material evaluated were all shade dependent. Comparison of pooled results revealed that none of the materials had good or excellent ratings and that the composite resins had significantly better hue/ chroma, value, and translucency match to the Vita shade guide than the other materials evaluated.

Color↗
PubMedDate not supplied

Fluoride release from fluoride-containing materials.

This in vitro study evaluated the amount of fluoride released from fluoride-containing materials over a period of 28 days. Six disk samples (2.06 +/- 0.06 cm2) were prepared of each material and divided at random into seven groups: Group 1: Chelon-Fil; Group 2: Chelon-Silver; Group 3: VariGlass; Group 4: Dyract; Group 5: Vitremer; Group 6: Vitremer + Scotchbond Multi-Purpose; Group 7: Fuji II LC. The cements were mixed according to the manufacturers' recommendations, placed in plastic molds, and pressed between two glass plates. Paraffined dental floss was incorporated into the cements during setting to serve as attachments. The materials in Groups 3, 4, and 5 were light cured (Heliolux) in two different positions for 40 seconds each. In Group 6, the adhesive was light cured in two different positions on both sides for 10 seconds each. The samples were stored at 100% relative humidity for 24 hours. Each sample was then suspended in individual plastic tubes containing 5 ml of deionized water and submitted to constant agitation at 25 degrees C. The water was changed every 24 hours. Fluoride release was determined at 1, 2, 3, 4, 5, 7, 14, and 28 days after buffering the solution with equal volume of TISAB. Fluoride release was measured with a fluoride ion-specific electrode (Orion 96-09) and an ionanalyzer (Orion EA 940) previously calibrated with standard solutions containing 0.05 to 5.00 micrograms F/ml. Fluoride release was expressed as ppm in solution and micrograms F/cm2. ANOVA and Student-Newman-Keuls tests were used to evaluate the data. The results revealed that Chelon-Fil released significantly (P < 0.001) more fluoride for the first 7 days than all the other products. This was followed by Fuji II LC, which exhibited significantly more fluoride release than the rest of the materials for the same 7 days. At days 14 and 28, Chelon-Fil, Dyract, and Fuji II LC released similar amounts of fluoride that were significantly greater than the other products. Group 6 (Vitremer + Scotchbond Multi-Purpose) released significantly less fluoride than the other materials at all time intervals. Fluoride release for all products at days 1 and 2 was significantly greater than the rest of the time intervals, except for Chelon-Silver, which released similar amounts of fluoride for days 2, 3, 4, and 5. Although significance for the remaining time intervals varied for all materials, all fluoride release decreased from day 1 to day 28.

Acrylic Resins↗
PubMed1996

Dentin bond strength of fluoride-releasing materials.

PURPOSE: To evaluate the shear bond strength to dentin of fluoride-releasing materials. MATERIALS AND METHODS: Human, noncarious extracted permanent molars stored in distilled water were used. Flat buccal and lingual dentin surfaces were ground wet on 600-grit silicon carbide paper. The teeth were then distributed at random into three groups of 8 teeth (16 surfaces) each: Group 1: Compoglass; Group 2: Fuji II LC; Group 3: Dyract. Cylindrical samples of the materials were prepared in plastic molds and bonded to the dentin surface according to the manufacturers' instructions. All samples were placed in distilled water for 24 hours, thermocycled for 500 cycles in distilled water at 6 degrees C and 60 degrees C and sheared with an Instron at a crosshead speed of 0.5 mm/minute. RESULTS: In MPa: Group 1: 16.29 +/- 5.35; Group 2: 15.42 +/- 4.77; Group 3: 15.33 +/- 6.96. ANOVA revealed that there was no statistically significant difference between the groups. Fracture patterns, examined with the SEM, revealed material cohesive failures for all groups.

Analysis of Variance↗
PubMed1997

Changes to Dyract restorative resin immersed in various media.

PURPOSE: To examine changes in weight, strength, fluoride release, and surface changes to the polyacid-modified resin composite Dyract after immersion in various media for periods up to 16 weeks. MATERIALS AND METHODS: Properties investigated were change in weight, strength, release of fluoride ions, and surface changes. Specimens were immersed in reverse osmosis deionized water (ROW) and in acetate buffer solutions containing calcium hydrogen orthophosphate. The acetate media were of pH3, pH5 and pH7. All solutions were maintained at 37 degrees C without agitation. Solutions were changed weekly and retained for fluoride analysis and specimens were weighed each week. After periods of 1, 2, 3, 4, 8, 12 and 16 weeks, some specimens were subjected to shear punch testing and SEM examination. RESULTS: All specimens except those in pH3 medium gained weight for the first 2-5 weeks after which weight was lost until all specimens weighed less than at the commencement of the study. The specimens in pH3 medium lost considerable weight from weeks 1 and 2. SEM examination showed disintegration of the surface of all specimens examined. Fluoride release peaked at 1 week in all specimens except those in pH3 medium. Fluoride release was highest in pH3 media (approximately 46 ppm) after 1 week and remained high for 7 weeks, after which it was reduced to about 50% of the initial release. Specimens stored in ROW and pH5 media released approximately 5 ppm after 1 week, and this was reduced to approximately 1 ppm (pH7) and 2 ppm (ROW) by week 6.

Cariostatic Agents↗
PubMed1997

Dentin bond strength of Dyract Cem.

PURPOSE: To evaluate the influence of provisional cements and of a dentin bonding agent on the adhesion of a self-curing polyacid-modified resin composite (Dyract Cem) on pressurized human dentin. MATERIALS AND METHODS: Freshly prepared dentin specimens of human teeth were perfused with physiologic saline. Three different types of surface treatment were evaluated. (1) Dyract Cem was applied to freshly prepared dentin without (Group 1.1) or with (Group 1.2) the respective dentin bonding agent (Prime & Bond 2.0) and cured. (2) Freegenol (Groups 2.1 and 2.2) or Temp Bond (Groups 2.3 and 2.4) were applied first on the dentin surface for 24 hours. Only then was Dyract Cem (with or without Prime & Bond 2.0) added onto the dentin after cleaning the dentin surface with pumice. 3) Prime & Bond 2.0 was applied first on the dentin surface and cured. Then Freegenol (Group 3.1) or Temp Bond (Group 3.2) were added for 24 hours. After cleaning with pumice, Prime & Bond 2.0 was applied for a second time on the dentin (= dual application) and finally Dyract Cem was added. As control, a conventional glass ionomer cement (Ketac-Cem Maxicap; Groups 4.1-4.3) was used in a similar way. After 1,500 thermal cycles with constant imitation of intrapulpal pressure, shear bond strengths were measured. Resulting shear bond strength values were displayed by means of a box plot and they were analyzed statistically by Mann-Whitney, Kruskal-Wallis or one way ANOVA tests. RESULTS: Lowest and highest mean shear bond strength values were 0.27 +/- 0.42 MPa (Group 2.4; single use of Prime & Bond 2.0 with prior application of TempBond) and 5.84 +/- 3.36 MPa (Group 3.1; dual use of Prime & Bond 2.0 with intermediate application of Freegenol). A clearly significant difference between groups could only be found when a single or dual use of the dentin bonding agent Prime & Bond 2.0 were combined with either Freegenol (Groups 2.1, 2.2 and 3.1; Kruskal-Wallis: P < 0.01) or Temp Bond (Groups 2.3, 2.4 and 3.2; Kruskal-Wallis: P < 0.001) as additional dentin surface treatment.

Adhesiveness↗
PubMed1997

Bond strengths of resin-modified glass ionomers and polyacid-modified resin composites to dentin.

PURPOSE: To measure the shear bond strength of two resin-modified glass ionomers (Vitremer and Fuji II LC) and two polyacid-modified resin composites (Compoglass and Dyract) when applied to dry dentin, dentin supplied with water pressure from the pulp, and after thermocycling. MATERIALS AND METHODS: Ninety six extracted third molars were used. The root portion was removed just below the cemento-enamel junction and the occlusal enamel was removed from the crown segment. An artificial root portion was made in Plexiglas, cemented to the crown segment and connected to a 36 cm. height water column. The tested materials were applied to the surface of dry dentin, dentin supplied with water pressure from the pulp, and after thermocycling. Shear bond strength was measured for the bonded specimens using an Instron at a crosshead speed of 0.5 mm/minute. RESULTS: There were no significant differences in bond strengths between Fuji II LC, Compoglass, and Dyract, which were significantly greater than that of Vitremer. The bond strengths of all materials were slightly increased or not affected by the presence of water pressure from the pulp. After thermocycling, the bond strengths of Fuji II LC, Compoglass, and Dyract were not significantly affected whereas those of Vitremer were significantly decreased.

Analysis of Variance↗
PubMedDate not supplied

Surface characteristics of tooth-colored restoratives polished utilizing different polishing systems.

The surface characteristics of different tooth-colored restoratives polished with the Enhance system, white stones, and the Super-snap system were evaluated using profilometry and microhardness testing. Surface characteristics of materials cured against a Mylar Uni-strip were used as a control. The results of this study show that the surface characteristics (roughness and hardness) following polishing with different systems are material dependent. The result may be attributed to the discrepancy between filler and matrix hardness of the restorative. Filler content, particle size, and the ability of the polishing system to abrade the filler may also contribute to the observed change in surface characteristics.

Analysis of Variance↗
PubMed1998

Fluoride release from three different types of glass ionomer cements after exposure to NaF solution and APF gel.

The objective of this study was to evaluate the fluoride release from three different types of glass ionomer cements and the fluoride release after exposure to NaF solution and APF gel. After determining the fluoride release during 28 days in artificial saliva, specimens were divided into two groups and exposed to NaF solution and APF gel for 2 min during 20 days. For each material, the release was highest during the first day, but Kromoglass released statistically significantly higher amounts of fluoride than the other. Vitrabond and Dyract followed in order. The differences in all groups were not statistically significant after third day. For statistical analysis: Paired- T Test, Variance Analysis and Duncan's Multiple Range Test were used. After exposure to NaF solution and APF gel all glass ionomer cements were recharged but the specimens exposed to APF gel were statistically significantly more recharged than NaF solution. As a result we conclude that glass ionomer cements can act as a rechargeable slow fluoride release systems and especially in caries active children, topical NaF applications with glass ionomer cements could be recommended as a preventive measure. We conclude that these results should be supported with long term and in vivo studies.

Acidulated Phosphate Fluoride↗
PubMedDate not supplied

Repair of new-generation tooth-colored restoratives: methods of surface conditioning to achieve bonding.

The shear bond strength of repaired resin-modified glass-ionomer cements and polyacid-modified composite resins after different methods of surface conditioning was studied. For the resin-modified glass-ionomer cement, none of the surface treatment methods had a significantly higher repair bond strength than the control. For the polyacid-modified composite, the application of low-viscosity resin after treatment with maleic acid, polyacrylic acid, and air abrasion appeared to be of paramount importance, for it enhanced bonding of the repaired specimens.

Acrylic Resins↗
PubMedDate not supplied

Resin-infiltrated dentin layer formation of new bonding systems.

The purpose of this study was to evaluate the resin-dentin interfacial morphology and shear bond strength of several new and experimental dentin bonding systems classified as single-bottle/total etch, multi-step/total etch, and self-etching. Class 1 and 5 cavities were prepared from freshly extracted permanent molars and restored with composite resin. Each bonded sample was cross sectioned and one-half was completely demineralized and deproteinized, while the other half was polished along the cut surface to permit measurement of the thickness of resin-infiltrated dentin layer (RIDL) within intertubular dentin (iRIDL) and around the peritubular walls (pRIDL) of resin tags by SEM. Shear bond strength was measured for all the systems 2 minutes after photocuring. SEM showed iRIDL and resin tags of different morphology depending on material and dentin location. The iRIDL was thinner in superficial dentin and thicker in deep dentin. Peritubular RIDL (pRIDL) was thinner than intertubular RIDL. Bond strength measurements varied from 12 to 21 MPa, depending on the materials used. Self-etching primer systems exhibited the highest bond strength, although one of the one-step/total etch systems also yielded very high values. The contribution of pRIDL to adhesion onto superficial dentin is limited by the small number of tubules. Single-component bonding agents produced SEM morphology and bond strengths similar to those of multi-step systems. Self-etching systems, despite their limited RIDL thickness, produced the highest immediate bond strengths. Bond strength did not correlate well with the thickness and morphology of RIDL.

Adult↗
PubMed1998

Bond strength to dentin with artificial carious lesions: influence of caries detecting dye.

PURPOSE: To evaluate the influence of dyes for caries detection on tensile bond strength of adhesive materials to artificial carious dentin. MATERIALS AND METHODS: Buccal and lingual enamel of human molars were removed leaving intact dentin surfaces. The entire surface of each specimen was covered with nail varnish, keeping a window area of 4 x 4 mm. Artificial carious lesions were induced with acidified gel. Three dyes (0.5% basic fuchsin; Caries Finder and Cari-D-Tect) were used according to manufacturers' recommendations. Specimens were etched with 35% phosphoric acid for 20 s, washed and dried, leaving a wet dentin surface. The adhesive system (Prime & Bond 2.0) was applied in two layers and light-cured. Restorative materials (TPH Spectrum, Dyract, Advance) were bonded using a 3-mm diameter inverted-cone mold. Control groups were made without dye. Eight samples were tested for each group. After 24 hrs of storage in distilled water, the samples were debonded using a testing machine at 0.5 mm/min crosshead speed. RESULTS: ANOVA and Tukey-Kramer test showed that TPH Spectrum (0.73 MPa) and Dyract (0.74 MPa) had similar bond strengths, and both were higher than Advance (0.0 MPa), which was statistically different (P < 0.01). The use of the dyes did not cause any changes in tensile bond strength for any tested materials.

Analysis of Variance↗
PubMedDate not supplied

Color attributes and accuracy of Vita-based manufacturers' shade guides.

The shades of several tooth-colored restoratives are now keyed to the Vita Lumin shade guide. The purpose of this study was to determine whether manufacturers' shade guides had color attributes that were similar to the Vita Lumin guide to which they are supposedly keyed. The overall color accuracy between the different guides was also compared via colorimetry. Results showed that none of the manufacturers' shade tabs evaluated had all L*, a*, and b* values that were identical to their respective Vita shade tabs. For the shades evaluated, manufacturers' tabs were generally darker than their corresponding Vita shade tabs. When shade guides were compared, the color accuracy of Z100 and Fuji II LC shade guides was significantly better than that of Durafill VS and TPH. Dyract's shade guide was the most accurate and was significantly better than the shade guides of Fuji II LC, Durafill VS, and TPH. The accuracy of manufacturers' shade guides was not consistently product dependent but was shade dependent.

Analysis of Variance↗