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At least 577 records · Page 32Linked to original sources
PubMed2005

Effect of resin hydrophilicity on tracer penetration. A preliminary study.

PURPOSE: To evaluate, by transmission electron microscopy, the extent of silver nitrate penetration into four polymerized resin blends with increasing degree of hydrophilicity after a period of 24 hours. METHODS: The uncured resin was polymerized in an experimental composite inlay processing chamber under a pressurized nitrogen atmosphere maintained at 551.6 KPa and light-activated for one complete cycle at 125 degrees C for 10 minutes. The resin blocks were sectioned occluso-gingivally into multiple 0.9 x 0.9 x 5 mm resin beams, and immersed in 50% basic, ammoniacal silver nitrate for 24 hours, exposed to a photodeveloping solution and prepared for transmission electron microscopy. The percentage distributions of silver deposits were compared using Kruskal-Wallis one-way analysis of variance (ANOVA) on ranks and Dunn's multiple comparison tests. RESULTS: No silver uptake occurred in the two most hydrophobic resins (Groups 1 & 2). The percentage distributions of silver deposits in the more hydrophilic Group 3 (6.23 +/- 1.35%) and 4 (5.08 +/- 1.09%) resins were significantly higher (P < 0.05) than were found in the more hydrophobic resins but Groups 3 and 4 were not significantly different from each other. The intensity of silver uptake increased with hydrophilicity of the resin blends. TEM examination revealed two types of silver deposits: fine spotted-type silver grains, and islands of interconnecting electron-dense clusters of silver grains. Phase separation of resin components was observed in Group 4 resin blends.

Analysis of Variance↗
PubMed2005

Effect of polymerization shrinkage on the sealing capacity of resin fillers for endodontic use.

PURPOSE: Recently, highly flowable resin fillers have been proposed for filling root canals using a single-cone approach. The purpose of this study was to test the hypothesis that polymerization shrinkage, which is inherent to this type of filler, can break the close initial contact between the main core and the surrounding dentin even if root dentin infiltration has occurred. MATERIALS AND METHODS: Twenty roots of anterior teeth were prepared chemomechanically and divided into 4 groups of 5 samples each. Groups 1 and 2: hydrophilic resin filler injected and spread, roots sectioned after setting; group 3: hydrophilic resin filler injected and spread, dental substrate dissolved after setting; group 4: hydrophobic resin sealer lentulo-spiraled and spread, roots sectioned after setting (as control). In groups 1, 2, and 3 the material was used following manufacturer's instructions. The section surfaces of groups 1 and 4, and the resin components of group 3 were processed for conventional FE-SEM. The section surfaces of group 2 were observed successively under environmental and high-vacuum conditions. RESULTS: Microscopic examination of the resin-dentin interfaces of groups 1 and 2 showed the existence of resin-dentin interdiffusion zones (RDIZ); however, the close initial contact between the main core and the surrounding dentin was often lost. In group 3, resin tag morphology was well characterized. Identical morphological features were observed in the resin-dentin interfaces in group 4. CONCLUSION: Since the existence of resin tags did not exclude the existence of a gap between the main core and the adjacent RDIZ, our results confirmed the proposed hypothesis.

Composite Resins↗
PubMed2005

GC-MS analysis of penta- and tetra-cyclic triterpenes from resins of Pistacia species. Part II. Pistacia terebinthus var. Chia.

Pistacia species contain oleoresins with bioactive triterpenes. In this study triterpenes, including minor components, were identified and quantified in both neutral and acidic fractions of Pistacia terebinthus var. Chia resin, grown exclusively in Chios island (Greece), collected traditionally, as well as using stimulating agents (liquid collection). It was proved that these two resin samples were composed of several different minor triterpenes, while major constituents were similar but in different proportions. Compounds that differentiated two resin samples of P. lentiscus and P. terebinthus var. Chia, both traditionally collected, were detected, in order to identify the nature of resins present in archaeological materials. In the traditionally collected resin, 37 triterpenes were identified, 12 in the acidic and 25 in the neutral fraction. In the liquid collection resin 10 compounds were identified in the acidic and 23 in the neutral fraction, while 16 compounds were not contained in the traditionally collected resin. The main triterpenes in both resin samples collected traditionally and using stimulating agents were: isomasticadienonic acid (23.6 and 26.3% w[sol ]w of the triterpenic fraction, respectively), 28-norolean-17-en-3-one (16.3 and 17.5% w[sol ]w of the triterpenic fraction, respectively) and masticadienonic acid (5.8 and 6.0% w[sol ]w of the triterpenic fraction). In this study the qualitative and quantitative composition of triterpenes was compared in the Pistacia lentiscus and P. terebinthus var. Chia resin samples collected with the traditional and new liquid techniques, and also triterpenes in resins of P. terebinthus obtained by the traditional technique and using stimulating agents. The aim of the study was also to examine whether the collection technique influenced the triterpenes contained in P. terebinthus var. Chia resin samples.

Gas Chromatography-Mass Spectrometry↗
PubMed2005

Permeability of adhesive resin films.

The purpose of this study was to quantify the permeability of adhesive resin films to water by measuring convective flow across thin films. Cured resin films were prepared with the use of five commercially available adhesive resins and an experimental resin. Two types of resin films were prepared from solvated comonomer blends within each product; resin films made before or after evaporation of solvent (10 s of drying with air-syringe). The permeability of the resin films was measured 30 min or 24 h after polymerization by placing the films in a split-chamber device. Fluid filtration rate through the resin films was measured with the use of 20 cm of water pressure. Osmotically induced water movement was measured by applying hypertonic aqueous solutions of CaCl2 or HEMA to the resin films. The results showed that evaporation of solvent before polymerization reduced the permeability of adhesive resin films, compared to permeabilities obtained without solvent evaporation. The cured adhesive resin films were all permeable to water, but to varying degrees.

Adhesives↗
PubMed1997

Dental application of polyfunctional urethane comonomers to composite resin veneering materials.

Urethane monomer/diluent monomer mixtures were used in dental composite resin veneering materials filled with various ratios of powder (filler)/liquid (comonomer), P/L. Hardness values of unfilled resins containing benzoyl peroxide only (BP0; 0.5 wt%), and filled resins (included trimethylol propane trimethacrylate (TMPT) composite filler) were tested. Significant increases in hardness were obtained with the use of TMPT composite filler in the resins. Also, their modulus values measured by bend test showed an increasing trend, compared to a commercial composite resin veneering material (a control sample; CONT) with a lower filler content (50 wt%). The DME-DPMDC/HPDM comonomer (dimethacryloxyethyl diphenylmethane-4,4'-dicarbamate/hydroxypropyl dimethacrylate), which showed a smaller fraction of surface porosity, gave greater mechanical strength values at P/L ratios of 0.55 (17.8 wt% filler content) to 1.20 (27.3 wt%) than a CONT resin. The coefficient of thermal expansion was smaller in urethane-based filling materials than a CONT resin. Also, greater activation energy of thermal decomposition was observed in the resin samples with P/L ratio 0.75 to 1.20 than in a CONT resin. Thermally-induced decomposition occurred with smaller weight loss in the experimental filled resins than in a CONT resin.

Journal Article↗
PubMed1994

Development of a radiopaque, autopolymerizing dental acrylic resin.

PURPOSE: Current prosthetic acrylic resins are radiolucent and cannot be imaged using standard radiographic techniques. If accidentally impacted or ingested, delays in localizing or removing the foreign body may be life-threatening. The purpose of this study was to evaluate the influence of an experimental radiopaque additive, triphenyl bismuth (TPB), on polymethyl methacrylate resins formulated for dental use. We also investigated methods to improve TPB-containing resin microbeads and optimize processing variables for specimen fabrication in autopolymerizing resin systems. MATERIALS AND METHODS: Selfcured samples of experimental resins were prepared containing 0% to 27% TPB and were tested according to American National Standards Institute/American Dental Association and International Organization for Standardization performance standards. A control group and two commercial provisional crown and bridge resins were used for comparison. RESULTS: The standard of radiopacity (> or = aluminum radiopacity) is met at TPB levels of > or = 14.5%. The control resin had a greater transverse deflection compared with the TPB-resin groups, but deflection was within standard limits for all resins. Polishability, color stability, and solubility were unaffected by TPB, whereas sorption decreased, although not significantly, at higher TPB levels. Translucency decreased at 27% TPB, and specimens containing 0% to 20% TPB were transparent. A tendency to entrain air bubbles, because of the hydrophobicity of TPB, resulted in increased susceptibility to brittle failure at the higher TPB levels. Solubility slightly exceeded American Dental Association standards for all TPB-resins and the control. All other performance standards were acceptable for resins containing 0% to 20% TPB. CONCLUSIONS: At concentrations that provide a diagnostic level of radiopacity, TPB does not significantly alter required performance and processing properties. Thus, TPB is capable of commercially acceptable performance as a radiopacifying additive for dental acrylics.

Analysis of Variance↗
PubMed2002

In vitro study of penetration of flowable resin composite and compomer into occlusal fissures.

UNLABELLED: The penetration of a sealant into the tooth fissures can establish longer retention time for a pit and fissure sealant restoration. AIM: This in vitro study was to evaluate the penetration ability of two low-viscosity resin materials, a composite and a compomer, applied with and without their bonding agents in comparison to an unfilled resin sealant. METHODS: Forty premolars with shallow/wide (group I) and forty with deep/narrow occlusal fissures (group II) were used. Each group was divided into five subgroups (A-E). The teeth in the subgroups were sealed as follows: A - Delton LC Clear (unfilled resin); B - Dyract flow (compomer); C - Prime&Bond NT (bonding agent) and Dyract flow; D - Tetric flow (resin composite); E - Syntac Sprint (bonding agent) and Tetric flow. Longitudinal sections were cut along the mesiodistal direction of fissures and examined under a videomicroscope. The resin penetration was rated according to the scale "low", "medium", "high", indicating penetration up to one third and two thirds of fissure depth and to the fissure bottom, respectively. RESULTS: These revealed the following: a) the penetration of all sealants was higher in shallow/wide than in deep/narrow fissures; b) the low-viscosity resin materials provided higher penetration than the unfilled resin sealant in shallow/wide fissures, whereas the unfilled resin achieved superior penetration rates in deep/narrow ones; c) the combination of a hydrophilic sealant (Dyract flow) with a hydrophilic bonding agent (Prime&Bond NT) significantly promoted the penetration depth in deep/narrow fissures. CONCLUSION: The penetration ability of all sealants was higher in shallow/wide than in narrow/deep fissures; low-viscosity resin composite and compomer provided higher penetration efficiency than the unfilled resin sealant in shallow/wide fissures, whereas the unfilled resin achieved superior penetration rate in deep/narrow ones. The combination of a hydrophilic sealant with a hydrophilic bonding agent significantly enhanced the penetration depth in deep/narrow fissures.

Journal Article↗
PubMed1989

Microleakage with Gluma: effects of unfilled resin polymerization and storage time.

An earlier study showed that the Gluma Bonding System permitted more microleakage than other dentin bonding agents. In that study, the unfilled resin was not polymerized prior to placement of the composite resin, as per manufacturer's instructions. The unfilled resin was cured in the other test groups. To evaluate the effect of unfilled resin polymerization on microleakage, Class V cavity preparations were made in sound extracted teeth. Composite resin restorations were placed using the Gluma Bonding System and a microfilled composite resin. In some samples, the unfilled resin was cured prior to placement of the composite. In others, the unfilled resin and composite were polymerized simultaneously. The samples were stored for either 24 hours or 30 days, then thermocycled. Microleakage was evaluated with a silver nitrate staining method. Specimens in which the unfilled resin had not been cured separately and which had been stored for 24 hours had the most leakage. Significantly less microleakage occurred when the unfilled resin was polymerized separately and/or when storage time was 30 days. To reduce microleakage with the Gluma Bonding System, the authors recommend polymerization of the unfilled resin before placement of the composite.

Aldehydes↗
PubMed2005

Temporary restorative resins using non-phthalate ester plasticizers.

OBJECTIVE: This study examined temporary restorative resins that use non-phthalate ester plasticizers. METHODS: Three non-phthalate plasticizers were tested: tri-ethyl citrate (TEC), tri-butyl citrate (TBC), and di-butyl sebacate (DBS). The experimental resins were compared with resins that use a phthalate ester plasticizer (di-butyl phthalate, DBP) and commercial products (Dura Seal, Plast Seal, and Fit Seal). For the experimental resins, the ratio of plasticizer to PMMA/MMA resin was varied from 30 to 60% (wt). The mechanical properties of the experimental resins were evaluated using a modified diametral compressive strength and the resistance to explorer insertion. RESULTS: The strengths of the experimental resins with plasticizer concentrations ranging from 40 to 50% (TEC, TBC, and DBP) or from 30 to 40% (DBS), by weight, were equivalent to the strengths of commercial temporary restorative resins. A similar tendency was seen for the resistance to explorer insertion. CONCLUSIONS: The results suggest that new temporary restorative resins can be prepared by choosing the appropriate proportions of resin monomer and non-phthalate ester plasticizer.

Citrates↗
PubMed1998

Retention of posts with resin, glass ionomer and hybrid cements.

OBJECTIVES: To measure and compare the retention of serrated root canal posts cemented with glass ionomer, resin and resin-modified glass ionomer (hybrid) cements. METHODS: Fifty single-rooted human teeth were decoronated, treated endodontically and then embedded in resin blocks. Standard post-holes, 10 mm long, were prepared to receive 1.5 mm serrated stainless steel posts. Five equal-sized groups of roots had posts cemented using either a glass ionomer cement, one of two resin cements or one of two resin-modified glass ionomer luting cements. The cements were prepared and used according to the manufacturers' instructions. The tensile force required to dislodge the cemented posts in a testing machine was recorded. Statistical analysis was performed using Student's t-test and Mann-Whitney U-tests at the 99.9% confidence level. RESULTS: Statistical analysis revealed that posts cemented with resin A were significantly better retained (340.06 N+/-23.13 N) than those cemented with resin B (212.56 N+/-67.62 N), or either of the two resin-modified glass ionomer cements (53.90 N+/-28.42 N, 25.97 N+/-14.70 N), but not statistically better than posts cemented with the glass ionomer cement (286.16 N+/-38.71 N). The retention of posts cemented with either resin B or the glass ionomer cement was significantly better than with either hybrid cement. There was no significant difference in retention between the hybrid cements. CONCLUSION: The performance of the resin-modified glass ionomer cements was significantly below that of alternative cements in this study. Possible explanations for this finding are discussed. Dentists should be cautious in adopting this new cementing regime.

Cementation↗
PubMed2002

Oxidative pyrolysis of organic ion exchange resins in the presence of metal oxide catalysts.

Pretreatment of the organic ion exchange resins by oxidative pyrolysis is effective for volume reduction before vitrification. In this work, pyrolysis of two nuclear-grade resins, Purolite NRW100 (cationic) and NRW400 (anionic), was examined using a laboratory-scale theromgravimetric analyzer (TGA) in air. It was shown that the cationic resin was harder to degrade and was less volatile compared to anionic resin. Off-gas data revealed the presence of SO2, CO2, CO, and H2O during oxidative pyrolysis of cationic resin from 30 to 800 degrees C. Trimethylamine, CO2, CO, and ethyl formate were found in the case of anionic resin. In addition, oxidative pyrolysis of the mixed resins (50/50 wt.%) showed the existence of the gases nearly at the temperatures where the gases would evolve if the results of two different resins were superimposed. Several metal salts including CuSO4*5H2O, CuO, and FeSO4*7H2O, as well as the ions Cu2+ pre-loaded on the resins had a catalytic effect on the oxidative pyrolysis of cationic resins, in which the decomposition of functional groups and polymer matrices was enhanced. Such catalytic effect was highlighted by a large decrease in activation energy calculated according to a degradation mechanism involving four consecutive reactions.

Catalysis↗
PubMed2006

Characterization of nano-clay reinforced phytagel-modified soy protein concentrate resin.

Phytagel and nano-clay particles were used to improve the mechanical and thermal properties and moisture resistance of soy protein concentrate (SPC) resin successfully. SPC and Phytagel were mixed together to form a cross-linked structure. The Phytagel-modified SPC resin (PH-SPC) showed improved tensile strength, modulus, moisture resistance, and thermal stability as compared to the unmodified SPC resin. The incorporation of 40% Phytagel and 20% glycerol led to an overall 340% increase in the tensile strength (over 50 MPa) and approximately 360% increase in the Young's modulus (over 710 MPa) of the SPC resin. Nano-clay was uniformly dispersed into PH-SPC resin to further improve the properties. The PH-SPC (40% Phytagel) resin modified with 7% clay nanoparticles (CPH-SPC) had a modulus of 2.1 GPa and a strength of 72.5 MPa. The dynamic mechanical properties such as storage modulus together with the glass transition temperature of the modified resins were also increased by the addition of clay nanoparticles. The moisture resistance of the CPH-SPC resin was higher as compared to both SPC and PH-SPC resins. The thermal stability of the CPH-SPC resin was seen to be higher as compared to the unmodified SPC.

Absorption↗
PubMed2002

Cytotoxicity of resin-based restorative materials on human pulp cell cultures.

OBJECTIVE: The objective of this study was to determine the cytocompatibility of 5 different extracts of resin-based restorative materials (2 resin-modified glass ionomer cements, 1 compomer, and 2 composite resins) on human pulp cells. STUDY DESIGN: Set specimens from 2 resin-modified glass-ionomer cements (Fuji II LC and Fuji IX), 1 compomer (Dyract), and 2 composite resins (Tetric and Superfil) were eluted with culture medium for 2 and 5 days. The effects of resin-based restorative materials on human pulp cells were evaluated with cytotoxicity and mitochondrial activity assays. RESULTS: The results showed that the eluates from resin-modified glass-ionomer, compomer, and composite resins were cytotoxic to primary human pulp cells. In addition, Superfil, Fuji IX, and Tetric demonstrated an inhibitory effect on mitochondrial activity of human pulp cells. It was found that composite resin Superfil was the most toxic restorative material among the chemicals tested. CONCLUSION: The influence of the cytotoxicity depended on the materials tested. Compomer or light-curing resin-modified glass ionomer may initially react more favorably to pulp cells.

Analysis of Variance↗
PubMed2001

Effects of two silane coupling agents, a bonding agent, and thermal cycling on the bond strength of a CAD/CAM composite material cemented with two resin luting agents.

STATEMENT OF PROBLEM: Surface treatment of CAD/CAM-generated composite material is important for a strong bond of resin luting agents to composite material. Purpose. This study evaluated the shear bond strengths of 2 dual-cured resin luting agents to a CAD/CAM composite material and the effect of silane coupling agent and bonding resin on the bond strength. MATERIAL AND METHODS: Rectangular- and disk-shaped CAD/CAM composite materials were untreated or treated with 1 of the 2 silane coupling agents or bonding resin and then cemented together with 1 of the 2 dual-cured resin luting agents. Half of the specimens were stored in water at 37 degrees C for 24 hours, the other half thermocycled 50,000 times before shear bond strength testing. Shear bond strengths were measured with a servohydraulic mechanical testing machine, and results were analyzed with 2-way analysis of variance. RESULTS: Surface treatment by silane coupling agent improved the shear bond strength when compared with nontreatment. Specimens treated with bonding resin showed significantly greater shear bond strength than the untreated groups. However, all specimens had the same adhesive failures at the composite-luting agent interface as untreated groups. When the CAD/CAM composite material was treated with 1 of the 2 silane coupling agents, no significant differences in bond strength were noted between water storage alone and after 50,000 thermocycles. For the 2 groups treated with bonding resin or silane coupling agent and cemented with 1 of the 2 dual-cured resin luting agents, there were significant increases in bond strength after 50,000 thermocycles, compared with specimens that were not subjected to thermal cycling. On the other hand, for the 2 untreated groups, there were significant decreases in bond strength after thermocycling. After 50,000 thermocycles, all specimens treated with silane coupling agent and then cemented with 1 of the 2 resin luting agents showed cohesive failures within the composite material. CONCLUSION: The application of a silane coupling agent to the CAD/CAM composite surface provided the highest bond strength between the resin luting agent and composite after long-term thermal cycling.

Adhesiveness↗
PubMed2005

Effect of curing environment on mechanical properties and polymerizing behaviour of methyl-methacrylate autopolymerizing resin.

Methyl-methacrylate autopolymerizing resin is used for multiple applications. Therefore, the mechanical properties of autopolymerizing resin should be assessed comprehensively including strength, stiffness and hardness. Any methods that effectively improve these mechanical properties are desirable. The objective of this study is to examine the effects of the curing environment: air or water with/without pressure, and air or water temperature during polymerization, on the strength, stiffness and hardness of autopolymerizing resin. In addition, we examined the polymerizing behaviour associated with the mechanical properties. Autopolymerizing methyl-methacrylate resin (Unifast II) was polymerized under the following conditions: in air and water with/without pressure at 10, 23, 30, 40, 60 and 80 degrees C. The resin specimens were subjected to a transverse test (three-point flexural test) and micro-Brinell surface hardness test. Fractured surfaces of the specimens after the transverse test were examined using a scanning electron microscope (SEM). The transverse strength and transverse modulus increased with increasing curing temperature in both wet and dry conditions. Pressured wet conditions increased transverse strength and transverse modulus over non-pressured wet and dry conditions. The resin polymerized in dry conditions showed higher surface hardness than the one polymerized in wet conditions at matching temperature. The SEM images of fractured surfaces cured at lower temperature exhibited porosity within the polymer base and cracks between the base and poly-methyl-methacrylate (PMMA) particulates. Surfaces of the resin polymerized in wet conditions were characterized with PMMA particulates having rougher surfaces suggestive of water incorporation. Raising temperature and pressuring during polymerization increase strength and stiffness of autopolymerizing resin. However, wet condition reduces surface hardness of resin compared with dry condition. These altered mechanical properties are associated with polymerization behaviour of the resin.

Acrylic Resins↗
PubMed1995

Tensile properties of resin-infiltrated demineralized human dentin.

The ability of adhesive resins to restore the physical properties of demineralized dentin has not been well-documented. The unfilled resins that are used for adhesion have relatively low moduli of elasticity and limited ability to increase dentin stiffness, although they may increase the ultimate tensile strength of dentin. This study tested the hypothesis that resin infiltration of demineralized dentin can restore its tensile properties to those of mineralized dentin. Small (ca. 0.5 mm thick x 0.5 mm wide) specimens of demineralized human dentin were infiltrated with one of five different dentin bonding resins over many hours, to determine how these resins altered the tensile properties of dentin. Tensile stress and strain were measured in these and control (mineralized and demineralized) specimens until their ultimate failure. The results indicate that some adhesive resins, after infiltrating demineralized dentin, can restore and even exceed the ultimate tensile strength of mineralized dentin. These resins increased the modulus of elasticity of resin-infiltrated dentin to values equal to or greater than those of the resins but far below those of mineralized dentin. Although the conditions in this experiment were far removed from the manufacturer's recommendations or clinical practice, the results support the potential of resin infiltration for reinforcing dentin.

Acid Etching, Dental↗
PubMed2006

Effect of resin coating on adhesion of composite crown restoration.

The purpose of this study was to evaluate the effect of a resin coating technique on the microtensile bond strength (microTBS) of resin cement to dentin in composite crown restorations. Crown preparations were done on human molars. A resin coating material, Hybrid Bond, was immediately applied to the prepared dentin and light-cured, while the tooth without resin coating acted as the control. An impression of the resin-coated tooth was taken, and a composite crown fabricated on the working cast. The composite crown was then bonded with a resin cement, Chemiace II. MicroTBSs were measured at a crosshead speed of 1 mm/min, and the resin-coated group yielded significantly higher microTBSs than the non-coated group (p < 0.05). In terms of microTBS values between the axial and occlusal surfaces, no regional differences in resin-dentin bond strength were detected (p < 0.05). It was concluded that resin coating with Hybrid Bond significantly improved the microTBS of resin cement to dentin in composite crown restorations.

Analysis of Variance↗
PubMed2000

Resin-modified glass-ionomer restorations and in vitro secondary caries formation in coronal enamel.

OBJECTIVE: The purpose of this laboratory study was to compare the effects of a resin-modified glass ionomer and a resin composite restorative material on secondary caries formation in coronal enamel. METHOD AND MATERIALS: Twelve caries-free molars were sectioned into tooth quarters. Coronal cavities were prepared and then restored with either a resin-modified glass-ionomer material (mesiobuccal and mesiolingual tooth quarters), or a resin composite (distobuccal and distolingual tooth quarters). Caries like lesions were created, and secondary caries was examined by polarized light microscopy following lesion initiation and progression periods. RESULTS: The resin-modified glass-ionomer specimens had significantly shallower primary surface lesions at both the lesion initiation (35% shallower) and progression (45% shallower) periods than did the resin composite specimens. There were significantly fewer wall lesions (3-fold and 2-fold fewer following lesion initiation and progression, respectively) in the resin-modified glass-ionomer group than in the resin composite group. CONCLUSION: Resin-modified glass-ionomer restorations reduce the susceptibility of unrestored adjacent enamel surfaces and cavosurfaces to a constant cariogenic challenge. The caries resistance imparted to the surface enamel and cavosurface is most likely due to the fluoride release from the resin-modified glass-ionomer material.

Composite Resins↗