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PubMedDate not supplied

Effect of surface treatment of prefabricated posts on bonding of resin cement.

This in vitro study evaluated the effect of various surface treatments of prefabricated posts of titanium alloy (ParaPost XH), glass fiber (ParaPost Fiber White) and zirconia (Cerapost) on the bonding of two resin cements: ParaPost Cement and Panavia F by a diametral tensile strength (DTS) test. The posts received surface treatments in three categories: 1) roughening by sandblasting and hydrofluoric acid etching; 2) application of primer by coating with Alloy Primer, Metalprimer II and Silane and 3) a combination treatment in the form of roughening (sandblasting or etching) supplemented by the application of a primer or in the form of the Cojet system. After surface treatment, the post was embedded in a cylinder of resin cement (diameter = 4.0 mm, height = 4.0 mm). The surface-treated post was centered in the resin cement-filled mold with the aid of fixation apparatus. Fifteen minutes from the start of mixing the resin cement, the specimen was freed from the mold and stored in water at 37 degrees C for seven days. Following water storage, the specimen was wet-ground to a final length of approximately 3 mm. The DTS of specimens was determined in a Universal Testing Machine. The bonding of resin cement to titanium alloy posts was increased by several surface treatments of the post. However, coating with primers as sole treatment had no effect on bonding. With the DTS method applied, none of the surface treatments had an effect on the bonding to glass fiber posts. The bonding of both resin cements to zirconia posts was improved by Cojet treatment, while sandblasting, followed by silane application, improved bonding of Panavia F.

Acid Etching, Dental↗
PubMed2003

Bond strength of resin cement to dentin and to surface-treated posts of titanium alloy, glass fiber, and zirconia.

PURPOSE: To determine the effect of surface treatments on bond strength of two resin cements (ParaPost Cement and Panavia F) to posts of titanium alloy (ParaPost XH), glass fiber (ParaPost Fiber White), and zirconia (Cerapost), and to dentin. MATERIALS AND METHODS: After embedding, planar surfaces of posts (n = 9 to 14) and human dentin (n = 10) were obtained by grinding. The posts received one of three surface treatments: 1. roughening (sandblasting, hydrofluoric acid etching), 2. application of primer (Alloy Primer, Metalprimer II, silane), or 3. roughening followed by application of primer (sandblasting or etching followed by primer, Cojet treatment). ParaPost Cement and Panavia F were bonded to the post and dentin specimens, and the bonded specimens were placed in water at 37 degrees C for 7 days. The specimens were debonded in shear. RESULTS: Panavia F had significantly higher bond strength to ground ParaPost XH, Cerapost, and dentin than did ParaPost Cement. Most surface treatments resulted in an improved bond strength of resin cements to the posts. Compared to the ground control, Cojet treatment and sandblasting were the most effective treatments. Etching of Cerapost with hydrofluoric acid with and without silane treatment significantly decreased the bond strength of Panavia F to the post. CONCLUSION: The bond strength of resin cements to the posts was affected by the material of the post, the surface treatment of the post, and by the type of resin cement. The bond strength of resin cement to dentin was influenced by the type of resin cement.

Acid Etching, Dental↗
PubMed2004

Finishing and polishing of direct posterior resin restorations.

UNLABELLED: Direct composite resin materials have revolutionized the delivery of minimally invasive treatment in the posterior region. Contemporary resin formulations provide improved strength, wear resistance, and aesthetics. Microhybrid formulations have also been associated with enhanced polishability. Development of an optimal surface polish in turn reduces stain and plaque accumulation, minimizes wear, and enhances the appearance of the definitive restoration. This article presents a simplified technique and protocol for finishing and polishing composite resin materials following restoration of the posterior region. LEARNING OBJECTIVES: This article discusses techniques and a protocol for finishing and polishing posterior direct resin restorations. Upon reading this article, the reader should: Understand the clinical protocol necessary to create direct posterior resin restorations that require minimal finishing. Be able to select appropriate instrumentation for direct posterior resin finishing and polishing procedures. Understand the importance of correct finishing and polishing on plaque accumulation, stain resistance, and wear resistance.

Bicuspid↗
PubMedDate not supplied

Mechanical properties of new denture resins polymerized by visible light, heat, and microwave energy.

Properties of seven newer resins polymerized using a water bath, microwave energy, or by visible light were measured. Generally, the new resins were harder and less flexible but had lower impact strength than did the heat-polymerized, rubber-modified resin (Lucitone). The light-activated urethane dimethacrylate resin (Triad) was the least flexible. Microwave polymerization improved the modulus of elasticity of two resins, decreased the impact strength of one, and had little effect on the properties of two other resins.

Acrylic Resins↗
PubMed1992

Composite-resin materials and techniques in dentistry.

Important features to consider when selecting composite resins are filler size and amount, radiopacity, and fluoride content. Submicron particles provide the best polishability, and heavily filled resins demonstrate better wear resistance. The radiopacity of the composite resin should slightly exceed that of enamel to allow visualization of the restoration and recurrent decay. Fluoride added to the matrix may arrest the progression of caries. Properly cured composite resins should not cause chronic pulpal irritation; however, infection of the cervical contraction gap resulting from poor bonding to root surfaces may cause pulpal irritation. Techniques to improve curing include incremental build-up, reflective matrices and wedges, and controlling the direction of light vectors. A surface sealant is highly recommended to reduce wear, especially in the posterior region. Porcelain veneers perform better clinically than do composite-resin veneers. Class I and II composite-resin restorations reinforce weakened tooth structure; however, problems with cervical leakage and wear prevent the recommendation of these materials for larger posterior restorations that involve occlusal contacts or that require bonding to root surfaces.

Composite Resins↗
PubMedDate not supplied

Influence of different beverages on the microhardness and surface roughness of resin composites.

This study assessed the influence of different beverages on the microhardness and surface roughness of microfilled (A110, 3M/ESPE), hybrid (Z250 3M/ESPE) and flowable (Flow, 3M/ESPE) resin composites, over time. Twenty-four disc-shaped specimens (10 mm; 2-mm thick) of each resin composite were fabricated, thereby forming three groups (n=24). Knoop microhardness and surface roughness (Ra) were analyzed at predetermined evaluation periods: 24 hours, and 7, 30 and 60 days after specimens fabrication. The 24-hour measurements were recorded after storage in artificial saliva. Next, each group (n=24) was divided into four subgroups (n=6) according to the test beverages: Coca-Cola, sugar cane spirit, coffee and artificial saliva (control). Control specimens were kept in saliva throughout the experiment (60 days). For experimental specimens, a 60-day testing cycle was carried out: specimens were initially stored in saliva for four hours, then submitted to a five-minute immersion in the beverages (Coca-Cola, sugar cane spirit, coffee) intercalated by immersions in saliva three times daily. Microhardness/roughness measurements were done at 7-, 30- and 60-day intervals. Data were submitted to three-way ANOVA and Scheffée test (p<0.05). It was observed that the tested beverages somewhat altered (p<0.05) the composites' microhardness and/or surface roughness. Knoop microhardness-for all resin composites, microhardness remained stable up to the 30-day record, decreasing significantly at the 60-day evaluation. During the interaction beverage X evaluation period, it was observed that the microhardness of materials immersed in coffee and Coca-Cola remained stable up to the seven-day measurement, showing a decrease at the 30-day record and a more accentuated drop at the 60-day evaluation (p<0.05). Specimens immersed in sugar cane spirit exhibited no significant change in microhardness up to the seven-day measurement, increasing significantly at the 30-day record and later decreasing at the 60-day evaluation. Surface Roughness--For all resin composites, surface roughness increased at the seven-day measurement, while decreasing at the 30-day record and even more at the 60-day record. In the interaction beverage X evaluation period, the surface roughness of specimens immersed in test beverages increased at the seven-day measurement, showing a gradual decrease at the following records (30- and 60-day evaluations). The findings of the reported research disclosed that all beverages altered, to some degree, the microhardness and/or surface roughness of the tested resin composites. The alterations' effects ranged from slightly adverse to a markedly negative impact on the composites' microhardness and surface roughness, depending on the characteristics of the materials, type of beverage and the evaluated period. Generally, the greater number of immersions in beverages resulted in a more accentuated impact on the resins' properties.

Alcoholic Beverages↗
PubMed2005

[Isolation and purification of total tubeimosides from Bolbostemma paniculatum by macroporous resin].

OBJECTIVE: To select the optimum purification process of all tubeimosides from Bolbostemma paniculatum by macroporous resin. METHOD: Static absorption test and deabsorption test were carried out to screen the best macroporous resin for all tubeimosides. The single factor test, orthogonal experimental designs and variance analysis were applied to optimize the manipulation parameters of macroporous resin. RESULT: The macroporous resin NKA possessed the strongest absorption ability to all tubeimosides among the 9 resins studied, in addition to an easy de-absorption property. The optimum absorption conditions were A2B3C1, namely concentration of feed 30 mg x mL(-1), diameter: height of the chromatography column 1:7, the weight ratio of raw material and resins 1:2. CONCLUSION: The above experimental results can provide experimental basis for large-scale purification process of all tubeimosides.

Cucurbitaceae↗
PubMedDate not supplied

Long-span, fixed-movable, resin-bonded fixed partial dentures: a retrospective, preliminary clinical investigation.

PURPOSE: Long-span, resin-bonded fixed partial dentures (FPDs) have been associated with higher debonding rates than short-span prostheses. The use of modified nonrigid connectors that allow movement between the abutments in long-span resin-bonded prostheses may reduce harmful interabutment forces that stress the metal framework and resin-bonded interface. This preliminary investigation aimed to evaluate the longevity of long-span resin-bonded FPDs of 4 or more units with a modified nonrigid connector and increased extension of the retainer framework around the major abutment. MATERIALS AND METHODS: Thirty-eight patients attended a clinical examination; each had been provided with 1 or more resin-bonded FPD of 4 or more units (43 prostheses). For each patient, the following data were recorded: gender, age, cementation date, and endodontic treatment, if performed. Data regarding the occurrence of any debondings and patient expectations were also recorded. RESULTS: The mean service life for the 43 prostheses was 46.9 months (SD 22.0), with a range of 12 days to 87 months. Three prostheses had debonded, resulting in a clinical retention rate of 92.2%. CONCLUSION: Long-span resin-bonded FPDs incorporating nonrigid connectors that allow independent movement between the major and minor retainer, combined with increased framework extension on the major abutment, appear successful in the short term. Further research is required to determine their long-term efficacy.

Adult↗
PubMedDate not supplied

In vitro study of the adherence of Candida albicans to acrylic resins: relationship to surface energy.

PURPOSE: This study aimed to determine whether small variations in the composition of the polymethylmethacrylate (PMMA) of widely used dentures produce differences in the degree of Candida albicans adherence and to relate any differences found to the surface energy of the resins, which appears to play a major role in the initial phases of microorganism adhesion. MATERIALS AND METHODS: A reference strain of C albicans (18.804 ATCC) and 11 different PMMAs (Vacalon, Inkotherm 85, Veracril, Probase Cold, Inkotherm Press, Inkotherm 85 T, Ruthinium, Vertex, SR Ivocap, Idoacryl, Lucitone) were used. Fifty specimens (15 x 10 x 1 mm) of each type were prepared. C albicans adhesion was determined by microorganism count under fluorescent optical microscope, and the surface energy of the resins was calculated by the contact angle method. P < .05 was regarded as significant. RESULTS: C albicans adhesion on the resins ranged from 7.12 cells/mm2 to 330.8 cells/mm2, with statistically significant (P > .05) differences in some cases. Despite small variations in the composition of the resins, their surface energy values were very similar (38.78 to 41.2 mJ/m2), and no relationship was found between C albicans adhesion and surface energy. CONCLUSION: The adhesion of C albicans to different resins varied in vitro, possibly as a result of the action of residual postpolymerization products. According to these results, variations in surface energy that result from differences in the composition of the different PMMA resins appear to have no influence on the adhesion of C albicans or, therefore, on the onset of denture stomatitis.

Acrylic Resins↗
PubMedDate not supplied

Volumetric polymerization shrinkage of resin composites under simulated intraoral temperature and humidity conditions.

This study measured the volumetric shrinkage of resin composites polymerized under temperature and humidity conditions simulating the oral cavity and compared them to those occurring under ambient room conditions. Small, semispherical specimens of a microhybrid (Z100), microfill (Filtek A110) and flowable microhybrid (4 Seasons Flow) resin composite were manually formed and light activated for 40 seconds using a halogen light-curing unit (Spectrum Curing Light). The volumetric polymerization shrinkage of 10 specimens of each brand of resin composite was measured using a drop shape analysis unit (Drop Shape Analysis System, model DSA10 Mk2) under each of two temperature/relative humidity conditions: room conditions (22 +/- 2 degrees C and 60 +/- 5%) and those simulating intraoral conditions (35 degrees C and 92 +/- 5%). Mean volumetric shrinkage values were calculated for each resin composite and the data were analyzed using two-way analysis of variance and t-test (a=0.05) to determine if significant differences existed between the amount of volumetric polymerization shrinkage that occurred under ambient room conditions and that which occurred under simulated intraoral conditions. Mean volumetric shrinkage values measured for the resin composites were: 2.26 +/- 0.04% (ambient) and 2.61 +/- 0.04% (intraoral) for Z100; 1.96 +/- 0.04% (ambient) and 2.28 +/- 0.04% (intraoral) for Filtek A110 and 4.53 +/- 0.06% (ambient) and 5.34 +/- 0.05% (intraoral) for 4 Seasons Flow. For each resin composite, statistical analysis indicated that the amount of volumetric shrinkage measured under simulated intraoral conditions was significantly greater than what was measured under ambient room conditions (p<0.0001).

Body Temperature↗
PubMed2005

A four-year clinical evaluation of a highly filled hybrid resin composite in posterior cavities.

PURPOSE: To evaluate the four-year performance of a highly filled resin composite in Class II and Class I cavities. MATERIALS AND METHODS: Each of 63 participants received at least one pair of restorations of the same size: one resin composite (Tetric Ceram) and one calcium aluminate cement. Seventy-one pairs were placed. The restorations were evaluated clinically according to slightly modified USPHS criteria at baseline, after 6 months, 1, 2, 3, and 4 years. At 3 years, the calcium aluminate cement material showed an inacceptable clinical cumulative failure frequency of 57% and its evaluation was discontinued. RESULTS: Postoperative sensitivity was reported for 5 restorations (2 resin composite, 3 calcium aluminate cement). At 4 years, a cumulative failure frequency of 7.5% was observed for the resin composite material. Reasons for failure were partial material fracture (2), cusp fracture (2) and endodontic treatment (1). CONCLUSION: An annual failure rate of 1.9% for the resin composite material provided a good clinical performance during the 4-year period, which fulfills the ADA criteria for posterior resin composite materials.

Adult↗
PubMed2006

Compatibility between an all-in-one self-etching adhesive and a dual-cured resin luting cement.

PURPOSE: To determine if bonding incompatibility between a single-step self-etching adhesive and a dual-cured luting cement is prevented by addition of deprotonizing anion exchange resin powder to the amine component of the resin cement. MATERIALS AND METHODS: iBond adhesive (IBO) (Heraeus Kulzer) and the dual-cured resin cement Twinlook (TWI) (Heraeus Kulzer) were used with base pastes, containing 0, 1, 2, and 4 wt% anion exchange resin (AER) in OH- form. Conventional shear bond strength (SBS) was determined on human dentin. After application of IBO, a cylindrical mold was clamped on the treated surface and bulk filled with TWI. SBS was measured after 24 h in 37degrees C water at a crosshead speed of 1 mm/min. The following curing protocols were investigated: Group 1: IBO not light cured, TWI redox cured; group 2: IBO light cured, TWI redox-cured; group 3: IBO light cured, TWI dual cured (n=8). The data were statistically analyzed using ANOVA and Duncan's post-hoc test at alpha < 0.05. RESULTS: The mean SBSs (MPa) with original TWI in groups 1, 2, and 3 were 12.7aA, 16.4bA, and 24.7cA. The corresponding figures for 1% AER were: 16.6aB, 23.0bB, 22.8bA; for 2% AER: 16.8aB, 22.6abB, 24.6bA; and for 4% AER: 16.2aAB, 22.5bB, 24.7bA. Different small and capital letters denote significant differences by treatment group and by AER content, respectively. CONCLUSION: Addition of anion exchange resin to the amine component of the dual-cured resin cement enhances the bond strength to dentin upon redox curing by prevention of amine neutralization through functional acid monomers from an all-in-one adhesive, mainly when the adhesive or the luting cement were not light cured.

Analysis of Variance↗
PubMed2006

Influence of opalescence and fluorescence properties on the light transmittance of resin composite as a function of wavelength.

PURPOSE: To determine the influence of opalescence and fluorescence properties on the light transmittance of resin composites as a function of wavelength (410-750 nm). METHODS: Spectral distribution of seven resin composites of A2 shade was measured according to the CIELAB color scale relative to the standard illuminant D65 in the reflectance and transmittance modes. Opalescence spectrum (OPS) was calculated as the subtraction spectrum (i.e., the spectrum measured in the transmittance mode subtracted at each wavelength from the spectrum measured in the reflectance mode). UV component of the illuminant was included and excluded to calculate the fluorescence spectrum (FLR and FLT in the reflectance and transmittance mode, respectively). Contrast ratio (CR) was calculated as the ratio of reflectance over a black background and over a white background. The total transmittance spectral distribution (TSD) value was used as the parameter to indicate masking ability of the resin composites over background color. Multiple regression analyses were performed among TSD and other optical parameters at the significance level of 0.05. RESULTS: In all the resin composites and wavelength range, correlation between CR and TSD was very high (r = -0.99). Correlations between each parameters varied by the wavelength range of fluorescence (410-500 nm) and no-fluorescence (510-750 nm). Correlation between OPS and TSD varied by the wavelength range (r = -0.86 to -0.94, P< 0.05). Fluorescence of resin composites increased the TSD values. Based on this in vitro study, the influence of opalescence and fluorescence of resin composite varied by the wavelength.

Composite Resins↗
PubMed1991

Degree of composite resin polymerization with visible light and argon laser.

A study was conducted to compare the degree of resin polymerization achievable using conventional visible light techniques and argon lasing. High performance liquid chromatography was used to extract unpolymerized resin from microfilled and small particle composite resin samples following photoactivation with visible light and the argon laser. It was determined that a significantly greater degree of microfilled resin polymerization was achievable following argon lasing compared to exposure to conventional visible light techniques. Although the small particle composite resin samples were polymerized as well as, or slightly better, with the argon laser, the differences were found to be insignificant. As a result, the argon laser should be considered a potentially advantageous method of initiating the polymerization of dental composite resin restorations.

Argon↗
PubMed1991

Dental composite resin porosity and effect on water absorption.

The aims of this study were: 1) to characterize the solubility and water absorption of different composite resins used as dental restorative materials; 2) to analyse their surface morphology using S.E.M. The resins tested were a mixture of glycidyl methacrylate (Bis-GMA) and TEGMA filled with silane-coated particles of inorganic fillers, and Bis-GMA and urethane resin. Cylindrical samples of composite resin were polymerized and stored in distilled water and weighed after different times. SEM analysis demonstrated voids and porous in several samples. The present study shows that dental restorative composite loose a small percentage of their components during storage time and that the type of resin, the nature of fillers and the methods of polymerization greatly influence water uptake and solubility of dental composite resin materials. These findings could explain the loss of anatomic form and the occlusal degradation of dental composites in "in vivo" conditions.

Absorption↗
PubMedDate not supplied

Penetration of etched enamel and dentin cavity surfaces by bonding agent/composite resin.

Mechanical and adhesive advantage of resin bonding agents depend upon the ability to penetrate microspaces created with acid-etchants and close adaptation to cavity surfaces. As a replicating material, these resins may reveal morphologic characteristics of the cavity surfaces not seen by direct scanning electron microscope (SEM) investigation. The purpose of this study was to describe, with the SEM, the resin replications of acid-etched cavity walls of Class V cavity preparations in the labial and lingual surfaces of extracted premolar teeth. Cavities were prepared in the gingival third of these surfaces in 26 freshly extracted human premolar teeth using fissure burs in water-cooled, high-speed handpieces. The cavosurface margins were bevelled. The preparations were washed in tap water, dried, etched for 20 seconds with 35% phosphoric acid, coated with light-cured bonding agent and filled with light-cured composite resin in two applications. The teeth were dissolved in acid and the cavity walls of the composite examined in the SEM. Features observed included: (a) Type II resin penetration of interrod regions, (b) resin penetration of the lamellae to the dentino-enamel junction (DEJ), (c) a 10-20 microns step in surface contour at the DEJ, with penetration of terminal tubule branches, (d) insular regions of deep dentin tubule penetration and (e) 100-300 microns deep, 10-30 microns incremental microlamellar penetrations into the enamel at the DEJ corresponding to enamel tufts.

Acid Etching, Dental↗
PubMed1990

[Composite resin inlays and onlays].

The establishment and development of composite resins has led to their use as a posterior restorative material. Although posterior composites have evolved considerably, both clinical studies and experience have confirmed that several problems still remain concerning their clinical properties and the relative complexity of handling the material. In order to resolve these problems, two different manufacturers have introduced composite resin systems for the fabrication of direct or indirect resin inlays and onlays which are cemented into the acid-etched preparation with a modified composite resin. Both systems are based on the same concept: the polymerization of the resin takes place out of the mouth in a special oven where a specific heat-curing procedure is followed. There is an essential difference between the two systems. When the direct resin system is used, the inlay is formed and partly light-cured into the tooth preparation, then it is removed for further polymerization. When the indirect system is used the procedure takes place in the lab where the inlay is formed on the die. This article presents both systems, the step-by-step procedure that has been followed in several clinical cases as well as their advantages and disadvantages.

Bicuspid↗
PubMed1990

[Fatigue properties of junction of crown and bridge resin and metal frame. 1. Effects of retention beads and adhesive].

The bending fatigue test of crown and bridge resin facing metal frame was carried out under a scanning electron microscope, and the fracture and propergation behavior of junction was studied. The resin facing metal frame with retention beads had a static breaking stress of about 100 kgf/mm2. The resin facing metal frame, when bonded with adhesive, had the stress of about 36 kgf/mm2. The specimens with retention beads and bonded with adhesive were not destroyed at cycles of 10(6) under the bending fatigue stress of below 40% and 50% of the static breaking stress, respectively. Marginal micro gaps between resin and metal frame with retention beads were observed before the fatigue test, and were increased with the number of cycles. Then fracture of the specimen occurred from the resin of the retention beads side. In the specimen bonded with adhesive, marginal micro gaps between resin and metal frame were observed during the fatigue test, and the partially cohesive fracture occurred.

Composite Resins↗