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The superior cementation strengths of the adhesive resin cements can now be used in the dental surgery for posts, crowns and bridges and for intra-oral repairs to fractured porcelain fused to metal crowns or bridges, thanks to the availability of miniature sandblasters and portable tin-platers. The author describes the techniques involved.
PURPOSE: The objective of this study was to test the following hypothesis: the silica coating on ceramic surface increases the bond strength of resin cement to a ceramic. MATERIALS AND METHODS: In-Ceram Alumina blocks were made and the ceramic surface was treated: G1--sand-blasting with 110-microm aluminum oxide particles; G2--Rocatec System: tribochemical silica coating (Rocatec-Pre powder + Rocatec-Plus powder + Rocatec-Sil); G3--CoJet System: silica coating (CoJet-Sand) + ESPE-Sil. The ceramic blocks were cemented to composite blocks with Panavia F resin cement (under a load of 750 g/1 min). The cemented blocks were stored in distilled water at 37 degrees C for 7 days and sectioned along the x and y axes with a diamond disk. Samples with an adhesive area of ca 0.8 mm2 (n = 45) were obtained. The samples were attached to an adapted device for the microtensile test, which was performed in a universal testing machine (EMIC) at a crosshead speed of 1 mm/min. RESULTS: The obtained results were submitted to ANOVA and Tukey's test. Mean values of tensile strength (MPa) and standard deviation values were: (G1) 16.8+/-3.2; (G2) 30.6+/-4.5; (G3) 33.0+/-5.0. G2 and G3 presented greater tensile strength than G1. There was no significant difference between G2 and G3. All the failures took place at the ceramic/resin cement interface. CONCLUSION: The silica coating (Rocatec or CoJet systems) of the ceramic surface increased the bond strength between the Panavia F resin cement and alumina-based ceramic.
The aim of this study was to evaluate early tensile bond strengths of three commercial resin cements (a dual-cured and two chemically cured) to bovine dentin. Bonding was performed in two environmental conditions, namely room environment (23 degrees C/50% RH) and oral environment (30 degrees C/80% RH). Tensile bond strengths were recorded at 10 minutes, 1 hour, and 1 day after the bonding procedure was completed and were analyzed using one-way ANOVA, Fisher's PLSD test, and Student's t-test. The results showed that bond strengths were statistically greater for all materials (P < 0.05) over time, except for Bistite Resin Cement between 10 minutes and 1 hour (P > 0.05). Variation between the bonding environments was observed only for Bistite Resin Cement at both 10 minutes and 1 hour, and Panavia 21 at 10 minutes. It was concluded that bond strengths were initially weak for the chemically cured materials, and all materials showed significantly greater bond strengths over the first 24 hours, but bonding environment had little influence.
The present study measured in vitro occlusal wear, quantity of remaining double bonds, and volumetric filler content of eight dual-cure resin cements. Furthermore, the effect of light curing on wear and quantity of remaining double bonds was evaluated. The filler content varied between 31 vol% and 66 vol%. In vitro wear varied between 30 microns and 65 microns, and quantity of remaining double bonds between 19% and 38% when resin cements had been both chemically cured and light cured. When light curing had been omitted, wear varied between 36 microns and 74 microns, and quantity of remaining double bonds between 25% and 56%. One resin cement did not harden when not cured by light. Light curing improved the wear resistance of three resin cements by up to 44% and reduced the quantity of remaining double bonds of six cements by up to 36%. A three-dimensional regression analysis found wear to decrease with decreasing quantity of remaining double bonds and increasing volumetric filler content. A negative correlation was shown between compressive strength and wear.
Plasma arc light units for curing resin composites have been introduced with the claim of relatively short curing times. The purpose of this study was to evaluate the efficiency of two different light sources to polymerize dual curing resin cement beneath porcelain laminate veneers. Twenty extracted healthy human maxillary centrals were used. Teeth were sectioned 2 mm below the cemento-enamel junction and crown parts were embedded into self-cure acrylic resin, labial surface facing up. Cavity preparation was carried out on labial surfaces. These teeth were divided into two groups of 10 each. The resin cement/veneer combination was exposed to two different photo polymerization units. A conventional halogen light (Hilux 350, Express Dental Products) and a plasma arc light (Power PAC, ADT) were used to polymerize resin cement. Ten specimens were polymerized conventionally (40 s) and the other specimens by plasma arc curing (PAC) (6 s). Two samples from each tooth measuring 1.2 x 1.2 x 5 mm were prepared. These sections were subjected to microshear testing and failure values were recorded. Statistically significant differences were found between the bond strength of veneers exposed to conventional light and PAC unit (P < 0.001). Samples polymerized with halogen light showed better bond strength. The results of this study suggest that the curing efficiency of PAC through ceramic was lower compared with conventional polymerization for the exposure durations tested in this study.
PURPOSE: The retention forces of a newly developed compomer cement (Dyract Cem), a glass ionomer cement (Ketac Cem Aplicap), and a resin cement (F21) were examined. MATERIAL AND METHODS: Cemented cast gold crowns were removed along the path of insertion with a Zwick universal testing device. The impact of both a cured and a noncured additional bonding layer that were applied to the inner surface of the crowns was examined across the Dyract Cem group. RESULTS: The mean adhesive strength was measured at 2.36 +/- 0.69 N/mm2 in the Ketac Cem group, at 0.60 +/- 0.28 N/mm2 in the F21 group, and at 1.85 +/- 0.94 N/mm2 in the Dyract Cem group, respectively. The application of an additional bonding layer to the inner surface of the crowns did not significantly improve the retentive strength of Dyract Cem; the respective mean strengths were observed at 1.46 +/-0.33 N/mm2 for the uncured and at 1.70 +/- 0.76 N/mm2 for the cured bonding layers. CONCLUSIONS: Dyract Cem and Ketac Cem showed significantly higher retentive strengths than F21 (p < 0.001, Wilcoxon test, 5% level). No significant difference was found in bond strength between Ketac Cem and Dyract Cem.
Reliable adherence of resin-based cements is of prime importance for the longevity of cemented restorations. The present study investigated whether a relationship exists between adherence energy to a metal substrate and the degree of cross-linking and wetting characteristics of resin-based luting agents. The adherence energies between a sand-blasted metal surface and a series of experimental resin cements were measured by means of the wedge test. The degree of cross-linking was calculated from the monomer composition of the resin cements. The measured wetting characteristics were work of adhesion and surface tension, and their dispersive and polar components. Adherence energy varied between 22 and 81 J/m2 and was influenced by the nature of the resin cements: Those with a low degree of cross-linking resulted in high adherence values. Furthermore, resin cements whose monomers were relatively polar gave rise to high adherence values. Although other metals may not behave in exactly the same way, these results may help in the formulation of new, more retentive resin cements.
PURPOSE: To evaluate the pulpal responses to a newly-developed MMA-based self-etch resin cement, when used as a luting agent for indirect resin composite restoration, and to compare the results with those obtained from a total-etch luting agent, glass-ionomer cement, and amalgam restoration. METHODS: 120 cervical cavities were prepared in monkey teeth and divided into four equal groups according to the restorative materials used: (1) the cavities were restored with resin composite inlays using a self-etch resin cement as a luting agent (M-Bond); (2) the cavities were also restored with resin composite inlays but using a total-etch resin cement as a luting agent (Super-Bond C & B); (3) the cavities were directly restored with glass-ionomer cement (Fuji II); or (4) the cavities were directly restored with amalgam (Dispersalloy). The restored teeth were extracted at 3, 30, or 90 days after restoration, then fixed in 10% neutral buffered formalin. The specimens were prepared using routine histopathological procedures. Five microm-thick sections were stained with hematoxylin and eosin or Brown & Brenn gram stain for bacterial observations. Histological responses in the pulpal tissue and bacterial penetration were observed under a light microscope and evaluated using standard scores. The results were statistically analyzed using the Kruskal-Wallis test (P< 0.05). RESULTS: At all time intervals, no significant differences of pulpal inflammatory responses between M-Bond and Super-Bond C&B were observed (P> 0.05). Both resin cements showed no serious pulpal responses, such as necrosis or abscess formation. In general, both MMA-based resin cements showed similar pulpal responses to those of glass-ionomer cement except for congestion of pulpal blood vessels at 3 days after restoration in which glass-ionomer cement exhibited a lower level than that of the MMA-based resin cements. For the group restored with amalgam, at 3 days after restoration, severe odontoblastic disorders and blood vessel congestions with a large infiltration of inflammatory cells were detected. At 30 and 90 days after restoration, slightly inflammatory irritations were observed irrespective of the materials used. Reparative dentin formation and bacterial penetration were found mostly in the group restored with amalgam.
PURPOSE: The effect of self-etching primer on the adhesion of tri-n-butylborane (TBB)-initiated resin cement to enamel has not been determined. This study evaluated the effectiveness of the self-etching primer by measuring the tensile bond strength between enamel and TBB-initiated methyl methacrylate (MMA) resin containing 4-methacryloxyethyl trimellitate anhydride (4-META). MATERIALS AND METHODS: The self-etching primers were an aqueous mixture of 30 wt% methacryloxyethyl phosphate, 35 wt% 2-hydroxyethyl methacrylate, and ferric chloride. The concentration of ferric chloride was varied from 0 to 7 wt%. The bovine enamel surface was treated with self-etching primer for 30 s. After drying, a stainless steel rod was bonded to the enamel using TBB-initiated 4-META/MMA resin cement. The tensile bond strengths were measured after 1 day of immersion in 37 degrees C water and after thermal cycles between 4 degrees C and 60 degrees C. The resin-enamel interface was observed under field-emission scanning electron microscopy (FE-SEM). RESULTS: The self-etching primer containing 5 wt% ferric chloride (Phosmer-5Fe) yielded the highest mean bond strength and significantly higher bond strengths than phosphoric acid etching after 1 day of immersion. After 5000 thermal cycles, the bond strength with Phosmer-5Fe was still significantly higher than that with phosphoric acid etching. FE-SEM images revealed tight bonding between the resin and enamel in the specimens of Phosmer-5Fe primer treatment. CONCLUSION: The self-etching primer treatment may be an alternative to phosphoric acid etching for the adhesion of TBB-initiated 4-META/MMA resin cement to enamel.
Reported studies have implicated eugenol in the reduction in retention of restorations luted with chemically cured composite resin cement. This study investigated the effect of residual eugenol in the root canal on the retention of ParaPost dowels cemented with Panavia EX composite resin. An attempt was also made to identify and to determine the most effective cleansing procedure. Findings of this study demonstrated a substantial decrease in retention of posts luted with Panavia composite resin cement in the presence of eugenol. Irrigation with ethyl alcohol (ethanol) or etching with 37% phosphoric acid gel was found to be effective in restoring the resistance to dislodgment of the posts, but alcohol produced the most consistent and reliable results.
Questions over the usefulness of a self-etching primer with resin adhesive in the bonding of orthodontic brackets remain unsolved. The purpose of this study was to determine the effects of using Multibond, a new methyl methacrylate (MMA)-based resin cement with self-etching primer, on the shear bond strength of orthodontic brackets compared with Superbond C&B, which is a well-known MMA-based resin cement containing phosphoric acid etching. Metal or plastic brackets were bonded to etched or self-etching primed bovine teeth using Superbond C&B or Multibond. The shear bond strengths were measured after immersion in water at 37 degrees C for 24 hours. Data were analyzed by two-way analysis of variance and Scheffe's test. The surface appearances of the teeth after phosphoric acid etching or self-etching priming were observed by field-emission scanning electron microscopy (FE-SEM). Metal brackets bonded with Multibond had a significantly lower shear bond strength than metal brackets bonded with Superbond C&B. No significant differences in shear bond strength were observed between Multibond and Superbond C&B when plastic brackets were bonded to the enamel. The shear bond strength of metal brackets bonded with Multibond was comparable with that of plastic brackets bonded with Superbond C&B. Adhesive remnant index score showed a tendency of more residual resin cement remaining on the teeth when metal brackets were bonded with Multibond. FE-SEM observation revealed less dissolution of the enamel surface resulting from treatment with Multibond self-etching primer as compared with phosphoric acid. Thus, the Multibond system may be a candidate for bonding orthodontic brackets with the advantage of minimizing enamel loss.
The color accuracy of resin composite cements and their corresponding try-in pastes was assessed. Three shades of three brands were compared using the cements alone and in contact with a standard porcelain disk. There were significant differences in color between resin cements and their corresponding try-in pastes. The addition of a 1-mm-thick porcelain disk greatly reduced the apparent color differences. The color of resin cements changed over time, but not significantly. Baseline measurements of resin cement colors were compared and measurements made after 24 hours of storage. Color changes were statistically significant but not perceptible, and all samples became slightly darker with age.
The purpose of this study was to test the feasibility of adapting a new microtensile testing technique to measure resin cement bond strengths to the cervical, middle, and apical thirds of root canals. Post spaces were created in extracted human teeth, and the roots were ground flat on one side to expose the canal and permit ideal placement of one of two resin cements (Panavia 21 or C&B Metabond). After 48 h of storage, serial 1-mm-thick cross-sections were cut to create 6-10 specimens per root. The first three specimens were from the cervical third, the next three were from the middle third, and the last three were from the apical third of the root. Each 1 x 1 x 8 mm specimen was pulled to failure in a miniature testing machine. The results indicated that both resin cements produced high bond strengths (12-23 MPa), and that bond strengths to the apical third were significantly higher (p < 0.05) than to the cervical or middle third with either cement. This new method shows promise for evaluating resin bond strengths within root canals.
PURPOSE: 1) To determine the surface energy characteristics of three variously treated post materials and two resin cements, and 2) to investigate if previously measured bond strengths between cements and treated posts could be related to the surface energy characteristics of the posts and cements. MATERIALS AND METHODS: The post materials were those of ParaPost XH, ParaPost Fiber White, and Cerapost, and the resin cements were ParaPost Cement and Panavia F. The post materials were surface treated by grinding, sandblasting, CoJet, or with Alloy Primer. Droplets of four reference liquids were placed on the surfaces and the contact angles measured. On this basis the dispersive, acid, and base components of the surface free energy of the materials were calculated. Then the thermodynamic work of adhesion between resin cements and treated post surfaces was calculated, as well as its dispersive and polar components. RESULTS: It was found that the surface energy characteristics varied significantly between the investigated surfaces. The previously measured bond strengths correlated statistically significantly (p < 0.02) to the dispersive component of the work of adhesion between posts and cements (r = 0.53), to the dispersive component of the surface free energy of the posts (r = 0.54), and to the contact angle determined with ethylene glycol as reference liquid (r = -0.52), but not to other surface energy characteristics. CONCLUSION: In spite of the significant correlations, the "explained" part of the variation in bond strength did not surpass 30%. This means that factors other than surface energy characteristics of adherend and adhesive play a role in determining the strength of the bond.
OBJECTIVES: Fluoroaluminosilicate glass and poly(acrylic acid) in small water phase was incorporated into resin composite cements to reduce or prevent secondary caries around luted restorations. The purpose of this study was to investigate the physical properties and the amounts of fluoride released from four types of visible light-activated resin cements. METHODS: A powder was composed of silanized SiO2 filler and 4.5 wt.% (G-4.5), 9.5 wt.% (G-9.5) or 19.5 wt.% (G-19.5) fluoroaluminosilicate glass and 0.5 wt.% reducing agent. The 45.25 wt.% triethylene glycol dimethacrylate (TEGDMA), 45.25 wt.% 2-hydroxyethyl methacrylate (HEMA), 9 wt.% poly(acrylic acid) solution in water and 0.5 wt.% camphorquinone were contained in a liquid. The powder and liquid were mixed at a 3:1 ratio by weight and the three types of specimen disks were cured using a photo-curing lamp. The TEGDMA-based composite cement was used as control (G-0). The specimens were immersed in water at 37 degrees C for 24 h or 6 months and compressive strength (CS) and diametral tensile strength (DTS) were evaluated for the four experimental materials. Disks prepared from the four resin cements were also immersed in deionized distilled water at 37 degrees C, and the fluoride released was measured over a period of 24 weeks. RESULTS: G-9.5 specimens showed almost the same CS and DTS as G-4.5 and G-0 specimens and significantly higher values for both parameters than G-19.5 specimens after 6 months of water storage. The amount of fluoride released from the three fluoride-containing resin cements continued to increase over the entire experimental period. The fluoride release rates of G-9.5 and G-19.5 resin cements were almost the same and were significantly greater than that of the G-4.5 resin cement. SIGNIFICANCE: G-9.5 containing 9.5 wt.% fluoroaluminosilicate glass may be a clinically useful resin cement due to its favorable physical properties and fluoride release.
The purpose of this study was to measure the bond strength of dual-cure resin cement at different regions of root canal dentin using three kinds of curing method. Thirty-six extracted bovine teeth were used. Each root was sectioned vertically into halves. Their pulpal dentin walls were polished flat and then applied with two dual-cure resin cements (Bistite II, Panavia F), and divided into three curing strategy groups: multi-direction light, one-direction light and no-light. The bonded specimens were sectioned perpendicularly to the long axis of the root into approximately 0.7 mm thick slabs within two-third of the root from the coronal end, and prepared for microtensile bond strength (muTBS) test. Knoop hardness of the cements was also measured. Within each curing strategy for both dual-cure resin cements, there were no significant differences between the muTBS values at the coronal third and mid third regions. The effect of curing method on bond strength and KHN was found to be dependent on the material.
This case describes intentional replantation with rotation of a complete vertically fractured root using adhesive resin cement. The fractured root was fixed with adhesive resin cement extra-orally. The tooth was replanted into the socket with rotation in order to avoid contact with the area where the periodontal ligament of the root surface was lost and the area where the alveola bone was lost along the fracture line. At follow-up 18 months later, the tooth was asymptomatic and radiographically showed an increase in the density of the alveolar bone, and the periodontal pockets were improved.
Some physical properties of zinc phosphate, zinc polycarboxylate, and a resin cement of thick consistency suitable for cementation of orthodontic bands were evaluated. A new technique for evaluating the setting time is described. The setting times for resin and zinc polycarboxylate cements were about the same but less than that for zinc phosphate. The properties of percent solubility and compressive strength were significantly superior for resin cement.