Factors affecting the adherence energy of experimental resin cements bonded to a nickel-chromium alloy

Effects of air abrasion with alumina or glass beads on surface characteristics of CAD/CAM composite materials and the bond strength of resin cements

Objective

The study aimed to evaluate effects of air abrasion with alumina or glass beads on bond strengths of resin cements to CAD/CAM composite materials.

Material and Methods

CAD/CAM composite block materials [Cerasmart (CS) and Block HC (BHC)] were pretreated as follows: (a) no treatment (None), (b) application of a ceramic primer (CP), (c) alumina-blasting at 0.2 MPa (AB), (d) AB followed by CP (AB+CP), and (e) glass-beads blasting at 0.4 MPa (GBB) followed by CP (GBB+CP). The composite specimens were bonded to resin composite disks using resin cements [G-CEM Cerasmart (GCCS) and ResiCem (RC)]. The bond strengths after 24 h (TC 0) and after thermal cycling (TC 10,000 at 4–60°C) were measured by shear tests. Three-way ANOVA and the Tukey compromise post hoc tests were used to analyze statistically significant differences between groups (α=0.05).

Results

For both CAD/CAM composite materials, the None group exhibited a significant decrease in bond strength after TC 10,000 (p<0.05). AB showed significantly higher bond strength after TC 10,000 than the None group, while CP did not (p<0.05). GBB exhibited smaller surface defects than did AB; however, their surface roughnesses were not significantly different (p>0.05). The AB+CP group showed a significantly higher bond strength after TC 10,000 than did the AB group for RC (p<0.05), but not for GCCS. The GBB+CP group showed the highest bond strength for both thermal cyclings (p<0.05).

Conclusions

Air abrasion with glass beads was more effective in increasing bond durability between the resin cements and CAD/CAM composite materials than was using an alumina powder and a CP.

Impact of different adhesives on work of adhesion between CAD/CAM polymers and resin composite cements

OBJECTIVE

To determine the impact of pre-treatment of adhesive systems on the work of adhesion (WA) between CAD/CAM polymers and resin composite cements and compare with conventional tests of previous studies.

METHODS

Surface parameters were measured by contact angle measurement (2700 measurements) and WA was calculated. Five CAD/CAM polymers were used for fabrication of specimens (n=75/subgroup): artBloc Temp (A), Telio CAD (B), Nano Composite CFI-C (C), exp. CAD/CAM nanohybrid composite (D), and LAVA Ultimate (E). Then, air-abraded specimens were pre-treated (n=15 per group): Ambarino P60 (I), Monobond Plus/Heliobond (II), visio.link (III), VP connect (IV), and no pre-treatment (V). Resin composite cement specimens (n=75) were smoothed out homogeneously on a glass plate (n=15/group): RelyX ARC (RXA), Variolink II (VAR), Panavia F2.0 (PAN), RelyX Unicem (RXU), and Clearfil SA Cement (CSA). Contact angles were determined with 3 drops of distilled water and diiodomethane each. Data were analyzed using Kruskal-Wallis-H test and Spearman-Rho correlation (p<0.05).

RESULTS

CAD/CAM materials (B), (A), and (C) showed higher WA compared to (D) and (E). (II) and (IV) resulted in higher WA than (I), (III) and (V). VAR had the significantly lowest WA, followed by RXU, RXA, CSA and PAN. No correlation occurred between WA and TBS/SBS whereas polar component of surface free energy of CAD/CAM resin and spreading coefficient showed significant positive correlation with TBS/SBS.

CONCLUSIONS

Determination of WA is not a proper method to draw conclusions about the bond between resin materials. Destructive test methods are not dispensable.

CLINICAL SIGNIFICANCE

The successful outcome of fixed dental restorations depends, among others, on the quality of bonding between the tooth and the restoration. Additional pre-treatment of the dental CAD/CAM resin restoration by bonding systems can be recommended for clinical use. Pre-treatment showed a significant impact on the surface properties.

Bond strength of overdenture locator posts cemented with seven luting agents

STATEMENT OF THE PROBLEM

Post retention is crucial factor in restoration survival. Posts are commonly failed due to loss of retention. It is unknown which luting agents would provide the maximum bond strength for Locator overdenture posts.

AIM

The aim of this study was to evaluate the bond retentive strengths of Locator overdenture posts cemented with 7 luting agents.

MATERIALS AND METHODS

One hundred and five single rooted human teeth were decoronated and randomly assigned to 7 groups (n = 15). Post spaces were prepared with Locator post drills to the depth of 6 mm. The Locator posts were cemented with Variolink II, RelyX ARC, Multilink N, RelyX Unicem, ParaCore, or MultiCore Flow resin luting agents. Zinc phosphate cement was served as control group. Specimens were stored in water at 37°C for 24 hours. Each specimen was loaded in tension in an Instron universal testing machine. The maximum force required to dislodge each Locator post was recorded. Means and standard deviations were calculated and data were statistically analyzed with one-way analysis of variance (ANOVA).

RESULTS

The highest mean bond strength value for Locator posts was recorded for MultiCore(®) Flow group (mean = 550.1 N), while the lowest mean value was for RelyX Unicem(™) resin cement group (mean = 216.8 N). A statistically significant difference in mean locator overdenture post bond strength was observed between the 7 cement types (p < 0.0001). ParaCore(™) and MultiCore(®) Flow groups had significantly higher bond strength than all other groups, but they were not differed from each other.

CONCLUSION

Bond strength of Locator overdenture posts were influenced by the type of luting agents. MultiCore Flow and ParaCore resin cements offered the greatest retention.

CLINICAL SIGNIFICANCE

The type of luting agents had a significant effect on the retention of Locator posts. The use of Core buildup resin cements as luting agent with Locator post demonstrated the greatest retention.

Shear bond strengths of various luting cements to zirconia ceramic: surface chemical aspects

OBJECTIVES

To measure the shear bond strengths of various luting cements to a sandblasted zirconia ceramic and to determine the surface energy parameters of the luting cements.

METHODS

Two conventional glass ionomer cements, two resin-modified glass ionomer cements, two compomer cements, and two adhesive resin cements were prepared and bonded to sandblasted zirconia (Lava). All bonded specimens were stored in water at 37°C for 48 h and then half of them additionally thermocycled 10,000 times prior to the shear bond strength test (n=10). Surface roughness (R(a)) values and surface energy parameters of the eight luting cements and polished zirconia ceramic were evaluated using a profilometer and contact angle measurements, respectively (n=10). The bond strength and surface roughness data were statistically analysed using non-parametric and parametric procedures, respectively (α=0.05). Relationships between surface energy parameters and measured shear bond strengths were investigated using the Spearman rank correlation test.

RESULTS

Panavia F 2.0 and Principle produced higher bond strengths than the other cements, with no significant changes before and after thermocycling. Fuji I, Ketac Cem Easymix, and Ionotite F yielded near-zero or zero values after thermocycling. All debonded specimens showed adhesive failure. Mean R(a) values ranged from 0.104 to 0.167 μm. We found the base (hydrogen bond accepting) components of the luting cements significantly affected the bond strengths both before and after thermocycling.

CONCLUSION

It is recommended that the surface energy parameters of luting cements be considered in evaluating their adhesive properties with zirconia ceramic.

Durability of the bond between resin composite cores and prefabricated posts

OBJECTIVES

This study evaluated the effect of post surface treatment and of storage condition on the bond between resin composite cores (Clearfil Core) and posts of titanium alloy (Fysika), silica-zircon fiber reinforced epoxy resin (SiliciumPost), and zirconia (CosmoPost).

MATERIAL AND METHODS

In the experimental groups, the coronal part of each post received sandblasting or tribochemical silicate-coating (CoJet) treatment. The coronal part of each post was embedded in a cylinder of resin composite core material with the aid of a fixation apparatus. After 15 min, the specimen was freed from the mold and stored in de-ionized water. The axial tensile strength (ATS) of posts was determined in a Universal Testing Machine when extracting the posts from the resin composite cores after: 1) 14 d water storage at 37°C, 2) 14 d water storage at 37°C followed by thermal cycling (6,000 cycles between 5°C and 55°C), or 3) 1 year water storage at 37°C. The results were statistically analyzed by three-way factorial ANOVA and Newman-Keuls' multiple range test.

RESULTS

The ATS values were generally higher for Fysika posts and SiliciumPost posts than for CosmoPost posts. Surface treatment effectively improved the ATS values of Fysika posts and SiliciumPost posts, but not those of CosmoPost posts. Thermal cycling or long-term water storage had only minimal effect on the ATS values of the posts.

CONCLUSION

Bonding of resin composite cores to the posts depended more on the material of the post and the surface treatment of posts than on the storage condition.

Effect of pH on the Wettability and Fluoride Release of an Ion-releasing Resin Composite

The effect of pH on the wettability and fluoride release of Ariston pHc was examined. It was determined that this material might interfere with plaque adhesion in the oral environment.

In vitro evaluation of push-out bond strengths of various luting agents to tooth-colored posts

STATEMENT OF PROBLEM

Different compositions of tooth-colored posts may influence the bonding capacity of various luting agents to these posts. An appropriate understanding of these interactions is presently unavailable.

PURPOSE

This study initially evaluated the effects of various pretreatment procedures on bond strengths to zirconium-oxide posts using a phosphate-methacrylate resin luting agent. Following that investigation, the bond strengths of various luting agents to tribochemically coated glass-fiber-reinforced composite (FRC) resin and zirconium-oxide posts were investigated.

MATERIAL AND METHODS

Two hundred zirconium-oxide posts (CosmoPost) divided into 10 groups (n=20) were luted into artificial post spaces prepared with drills provided by the manufacturer. In 4 groups the posts were luted with phosphate-methacrylate resin agent (Panavia F) after receiving one of the following pretreatment procedures: no treatment (control); airborne-particle abrasion; silica coating and silanization with an intraoral airborne-particle-abrasion device (CoJet); or silica coating and silanization with a laboratory airborne-particle-abrasion device in combination with airborne-particle abrasion (Rocatec). The other zirconium-oxide posts in the 6 remaining groups were silica coated (CoJet), silanated, and luted with 1 of 6 different luting agents (Multilink, Variolink, PermaFlo DC, RelyX Unicem, Clearfil Core, and Ketac Cem). Additionally, 60 FRC posts (FRC Postec) were silica coated (CoJet), silanated, and luted with 1 of the 6 resin luting agents (Panavia F, Multilink, Variolink, PermaFlo DC, RelyX, and Clearfil Core). Push-out tests were performed to evaluate the bond strengths between luting agents and posts. Qualitative scanning electron microscopy (SEM) analyses were performed to evaluate the effects of the pretreatment procedures on the surface of the zirconium-oxide posts. Data were analyzed using analysis of variance (ANOVA) followed by the post hoc Tukey B test (alpha=.05).

RESULTS

Bond strengths to the posts were significantly affected by the type of luting agent and the type of post (P<.001; 2-way ANOVA). Bond strengths of all luting agents to the FRC posts were significantly higher than to the zirconium-oxide posts (P<.01), except for Multilink and PermaFlo DC, which demonstrated higher bond strength values to the zirconium-oxide posts (P<.001). Pretreatment procedures significantly increased the bond strength of Panavia F to the zirconium-oxide posts (P<.05). SEM analyses revealed distinctive irregularities on the surface of the pretreated zirconium-oxide posts compared to the untreated posts.

CONCLUSION

Bond strengths of luting agents to tooth-colored posts are significantly affected by the type of luting agent and the type of post. All investigated pretreatment procedures of zirconium-oxide posts significantly increased the bond strength of Panavia F.

Resin composites: Strength of the bond to dentin versus surface energy parameters

OBJECTIVES

The strength of the bond to dentin treated with two adhesive systems was investigated. The bond was tested with six resin composites. It was hypothesized that the surface energy parameters of composite and adhesive-treated dentin would influence the bond strength.

METHODS

The investigated adhesive systems were Prompt L-Pop and OptiBond FL, which were used as recommended. The bond strengths were tested in shear. The dispersive, the acid, and the base component of the surface energy were determined from measurements of the contact angle of four test liquids placed on the composites and on the adhesive-treated dentin. Relationships were investigated by regression analysis.

RESULTS

The strength of the bond to dentin varied with the resin composite and with the adhesive system. The bond strength with both adhesive systems increased with the base component of the surface energy of the resin composites. Dentin treated with OptiBond FL had higher surface energy and gave higher bond strengths than was the case with Prompt L-Pop.

SIGNIFICANCE

It is advisable to use a resin composite that is compatible with the adhesive system.

Effect of adhesive resin cement on design of partial veneer crowns

STATEMENT OF PROBLEM

Procedures involved in the tooth preparation, impression, and casting of partial veneer three-quarter crowns are considered to be complex.

PURPOSE

This study assessed whether a simplified partial veneer crown design, when cemented with a 4-META adhesive resin, had a comparable resistance to displacement forces compared with a conventionally prepared partial veneer crown cemented with a traditional luting agent.

MATERIAL AND METHODS

Conventional partial veneer crowns were prepared on 20 natural premolars, and 20 other premolars received modified partial veneer crown tooth preparations without proximal grooves. Artificial crowns were made for these teeth with Students alloy. Half the crowns in each of the 2 groups were luted with 4-META resin; the other half were luted with a zinc phosphate cement. Loads required to displace the partial veneer crowns were recorded after 24 hours and thermocycling, then the mode of separation was recorded for each crown. Average force required to displace partial veneer crowns for the 4 groups were subjected to 2-way analysis of variance and Scheffé test.

RESULTS

The 2 groups luted with 4-META resin and the group with proximal grooves luted with zinc phosphate were not significantly different. However, they were all greater than the group without proximal grooves luted with zinc phosphate cement.

CONCLUSION

Forces required to displace partial veneer crowns prepared in a traditional manner and those teeth prepared without proximal grooves were similar if the artificial crowns were luted with adhesive resin cement.

Dental luting agents: A review of the current literature

STATEMENT OF PROBLEM

The practice of fixed prosthodontic has changed dramatically with the introduction of innovative techniques and materials. Adhesive resin systems are examples of these changes that have led to the popularity of bonded ceramics and resin-retained fixed partial dentures. Today's dentist has the choice of a water-based luting agent (zinc phosphate, zinc polycarboxylate, glass ionomer, or reinforced zinc oxide-eugenol) or a resin system with or without an adhesive. Recent formulations of glass ionomer luting agents include resin components (resin-modified glass ionomers), which are increasingly popular in clinical practice.

PURPOSE

This review summarizes the research on these systems with the goal of providing information that will help the reader choose the most suitable material.

MATERIAL

The scientific studies have been evaluated in relation to the following categories: (1) biocompatibility, (2) caries or plaque inhibition, (3) microleakage, (4) strength and other mechanical properties, (5) solubility, (6) water sorption, (7) adhesion, (8) setting stresses, (9) wear resistance, (10) color stability, (11) radiopacity, (12) film thickness or viscosity, and (13) working and setting times. In addition, guidelines on luting-agent manipulation are related to available literature and include: (1) temporary cement removal, (2) smear layer removal, (3) powder/liquid ratio, (4) mixing temperature and speed, (5) seating force and vibration, and (6) moisture control. Tables of available products and their properties are also presented together with current recommendations by the authors with a rationale.

Surface energy characteristics of adhesive monomers

OBJECTIVES

The aim of the investigation was to determine the surface free-energy components of potentially adhesive monomer mixtures.

METHODS

Four liquids with known components of surface free-energy were used as reference. Small drops of the liquids were placed on the polished surfaces of four types of solid (metal, porcelain, resin composite and hydrocarbon), and the contact angles were measured. By means of the fundamental equations for wetting, the three components of the surface free-energy of the four solids were calculated. Small drops of various monomeric mixtures were then placed on the four solid surfaces, and on the basis of the previously calculated components of surface free-energy of the solids, the surface energy characteristics of the monomeric mixtures were determined. The relationships between contact angles and composition, and between surface tension and composition, were studied by regression analyses. Comparisons between values were carried out by means of Neuman-Keuls' multiple range test at a level of statistical significance of p = 0.05.

RESULTS

Statistically significant differences between the monomeric mixtures as regards the wetting of the four solids were observed. These differences reflected differences in the acid or base component of the surface free-energy of the monomers. In particular, monomeric mixtures containing HEMA, MAN or 4-META exhibited a significant acid component of the surface free-energy.

SIGNIFICANCE

Knowledge of the surface free-energy components of monomers throws light on the mechanisms associated with the adhesion of resin composites, including resin cements. A better understanding of the interfacial interactions may act as guide in a research aimed at developing resin materials of increased adhesion to metal, porcelain or resin composite.

Bonding of resin cements to a metal substrate: influence of pretreatment on the adherence energy

The adherence of resin cements to restoration as well as tooth structure is of prime importance for the longevity of cemented restorations. It was the aim of the study to investigate the effect of an acid and a base primer on (i) surface polarity of a nonprecious alloy and on (ii) adherence energy of resin cements bonded to the alloy. The beams were pretreated with a 3% acetone solution of either maleic acid or N,N-diethanol-p-toluidine, and the solvent evaporated. The polarity was determined by means of measurements of contact angles. The adherence energy was measured by means of the wedge test, according to which 2 beams were glued together with the resin cement. A wedge was introduced between the joined beams to create a fissure, and on the basis of the length of the fissure, the adherence energy was calculated. It was found that the polar component of the surface free energy of the alloy increased as a consequence of the pretreatments. The results also showed that the pretreatments gave rise to an increase in adherence energy of 11-15 J/m2, equivalent to relative increases of 22-54%. The observed increases in adherence energy may be due to an increase in polar interactions at the interface between adhesive and substrate.