Adhesive Luting Systems Research Articles

Metal-Ceramic Resin-Bonded Fixed Partial Dentures After a Mean Observation Time of 7.5 Years.

To generate data on the long-term survival of metal-ceramic resin-bonded fixed partial dentures (RBFPDs). A total of 89 patients received 94 RBFPDs, 5 of whom (women n = 1; men n = 4) received 2 RBFPDs each. All RBFPDs were fabricated as two-retainer end-abutment metal-ceramic restorations. Clinical follow-ups were performed 6 months after cementation and then annually thereafter. The mean observation time was 7.5 years. Cox regression was performed to test the effects of the variables: gender, location, arch, design, use of rubber dam, and adhesive luting system. Survival and success were calculated using Kaplan-Meier curves. As a secondary objective, patient and dentist satisfaction with the esthetics and function of the RBFPDs was evaluated. The significance level was set at α = .05 for all calculations. Estimated Kaplan-Meier failure-free survival was 97.5% (standard error [SE] 1.7) after 5 years and 83.3% (SE 5.3) after 10 years. Calculated intervention-free survival (success) was 90.1% (SE 3.4) after 5 years and 65.5% (SE 6.7) after 10 years. Debonding-free survival was 92.6% (SE 2.9) after 5 years and 80.6% (SE 5.4) after 10 years. Cox regression revealed that none of the four tested variables had a significant effect on the incidence of complications in RBFPDs. Patient and dentist satisfaction with RBFPD esthetics and function was consistently high throughout the observation period. Within the limitations of an observational study, RBFPDs achieved clinically successful outcomes over a mean observational period of 7.5 years.

Fracture resistance of ultrathin occlusal veneer fabricated by different CAD/CAM materials

Purpose The purpose of this in vitro study was to evaluate the fracture resistance of ultrathin occlusal veneer fabricated by different CAD/CAM materials. Methods The occlusal surface of 40 extracted lower premolars was prepared in the enamel layer and restored with occlusal veneers with fissures/cusp thickness of 0.5/1 ml made from two different dental CAD/CAM materials. Groups of the study included the following. Group I: lithium disilicate glass-ceramic n = 20; the group was further divided into two subgroups according to the thickness of each of them. Subgroup A: (n = 10) 0.5 mm and subgroup B: (n = 10) 1 mm. Group II: Cerasmart n = 20 is further divided into two subgroups according to the thickness of each of them. Subgroup A: (n = 10) 0.5mm, subgroup B: (n = 10) 1 mm. Occlusal veneers were etched with ceramic etch (Ips ceramic etching gel/ATZGEL-IVOCLAR AG) and then bonded using an adhesive luting system (G-MULTI PRIMER and G-CEMTM Veneer) light cure adhesive resin cement (G-CEHTM veneer). The prepared teeth were etched using phosphoric gel and bonded using Bisco All bond universal. All specimens were subjected to load till fracture; these loads were recorded and statistically analyzed using the one-way ANOVA. The mode of failure of the specimen was classified; the correlation between fracture strength and mode of failure was analyzed. Results In this study, fracture strengths (mean ± standard deviation) of cerasmart recorded were 0.5 mm (887.71 ± 284.79N), 1 mm (953.73 ± 214.06N), and for lithium disilicate 0.5 mm (455.16 ± 134.96N), 1 mm (768.59 ± 154.08N). Cerasmart had significantly higher fracture strength than lithium disilicate in 0.5 mm thickness, and significantly different fracture strength in 1 mm thickness. Most specimens (31 from 40) had been fractured in the restoration without involving the tooth structure. Conclusion The Cerasmart material could be considered a valid alternative to IPS e.max material.

Influence of elapsed time between airborne-particle abrasion and bonding to zirconia bond strength

ObjectiveThe airborne-particle abrasion of zirconia with alumina particle (APA) has been reported to result in the durable bonding of appropriate adhesive luting systems. However, whether a delay between APA and the application of the adhesive luting material might affect the resulting bond strength and its durability is unknown. MethodsA total of 140 disc-shaped zirconia specimens were divided according to the elapsed time between the APA of zirconia and its bonding into 5 test groups (15 min, 1 h, 4 h, 24 h, and 72 h). The specimens were airborne-particle abraded with 50-μm Al2O3, and then stored at room temperature according to the test group (n = 28/group). Surface free energy (SFE) was measured for 12 specimens per group using a goniometer. For each group 16 Plexiglas tubes filled with composite resin were bonded to the zirconia specimens with an adhesive luting resin (Panavia 21). Tensile bond strength (TBS) was tested for subgroups of 8 specimens after water storage for 3 days and for 150 days with 37,500 thermal cycles. ResultsSFE decreased significantly within 24 h after APA. TBS after 3 days of water storage ranged from 38.3 (1 h) to 28.4 MPa (24 h) and after 150 days with thermocycling from 38.3 (15 min) to 24.8 MPa (24 h). SignificanceBased on these results, the time between the APA of zirconia and the application of adhesive materials should be minimized when bonding nonretentive zirconia restorations clinically.

Effect of proanthocyanidin on push-out bond strength between fiber post and root dentin- An in-vitro study

Aim: The aim of this study was to assess the influence of Proanthocyanidin (PA) application on bond strength of glass fiber posts to root canal dentin using self-etch adhesive luting system. Materials and Methods: Twenty single rooted mandibular premolars, freshly extracted for orthodontic purpose, were decoronated below the cementoenamel junction, and standardized to 14mm in length. Post space preparation was done upto No 3 Peeso reamer during which canals were irrigated with conventional irrigation protocol. Teeth were randomly divided into two groups (n=20 each) Group 1: Pre-treatment with PA and Group 2 served as the control group. Both Groups were restored with fiber posts bonded with RELYX U200 self-etch adhesive system. Teeth were then stored in distilled water for three months at 37° C. One mm slices were obtained and push-out bond strength testing was performed. Failure patterns were assessed under stereomicroscope at 20x magnification. Results: Individual bond strength values were calculated and statistically analysed with the chi-square test and independent-t-test. A statistically significant difference existed between the two Groups (p

Dentin microshear bond strength of various resin luting agents to zirconia-reinforced lithium silicate ceramics

Statement of problemThe performance of adhesive and resin luting cements used to bond zirconia-reinforced lithium silicate (ZLS) ceramics to dentin has not been well established. PurposeThe purpose of this in vitro study was to examine the microshear bond strength (μSBS) of an etch-and-rinse adhesive system, a universal adhesive, and a self-adhesive resin cement that were used to bond ZLS to dentin. Material and methodsVITA Suprinity (VS) and Celtra Duo (CD) blocks were sectioned into 36 and 72 microbars (1×1×3 mm). All VS were crystallized, while half of CD were additionally fired and defined as fired-Celtra Duo (FCD). The others were defined as unfired-Celtra Duo (UCD). Each microbar was cemented to each flat occlusal dentin surface of a human first premolar, following the adhesive luting systems: Scotchbond Multi-purpose (SM), Single Bond Universal (SU) combined with RelyX Ultimate, and RelyX Unicem (U2) (n=12 per group). μSBS at 24 hours was then determined, and the data were analyzed by using 2-way ANOVA and a Tukey post hoc test (α=.05). Failure modes were analyzed under a stereomicroscope at ×40 magnification. ResultsTwo-way ANOVA revealed that the type of ZLS had no influence on μSBS (P=.699). However, the kinds of adhesive luting cements and their interaction had a statistically significant effect on μSBS (P<.001 and P=.002). U2 had a statistically significant lower mean μSBS, regardless of the type of ZLS, than SM and SU (P≤.05), while UCDU2 did not show a statistically significant difference in μSBS from UCDSU (P=.478). ConclusionsResin cement used with an etch-and-rinse and a universal adhesive agent demonstrates higher bond strength for the cementation of zirconia-reinforced lithium silicate ceramics to dentin than a self-adhesive resin cement.

Bond strength of adhesive luting systems to human dentin and their durability

Statement of problemThe durability of adhesive bonding systems to dentin is of importance for restoration longevity; therefore, new adhesive systems should be tested in vitro with long-term artificial aging before clinical application. PurposeThe purpose of this in vitro study was to investigate the bonding durability of 3 dual-polymerizing resins and 1 autopolymerizing resin to human dentin with their specific self-etching primers or adhesives. Material and methodsAcrylic resin tubes filled with composite resin were bonded to human dentin disks using either an autopolymerizing resin system (Panavia 21) or dual-polymerizing resin systems (Panavia V5, RelyX Ultimate, and Variolink Esthetic DC) together with the system-specific primer or adhesive. Tensile bond strength was tested after 3 days of water storage or after 150 days of water storage with 37 500 thermocycles (5 °C to 55 °C). The failure mode was evaluated by using a light microscope. In addition, representative specimens were examined by using a scanning electron microscope. ResultsAfter 3 days, the median tensile bond strengths ranged from 18.8 to 29.1 MPa. After artificial aging for 150 days, the median tensile bond strengths ranged from 14.7 to 25.6 MPa. The dual-polymerizing resins showed significantly higher bond strength than the autopolymerizing resin (P≤.05). Artificial aging with thermocycling had no statistically significant influence on tensile bond strength for the adhesive resin systems tested (P>.05). The failure mode was mainly adhesive for the autopolymerizing resin, whereas it was mainly cohesive for the dual-polymerizing resins. ConclusionsThe 3 tested dual-polymerization resin systems provided durable bond strengths to dentin which were higher than those of the autopolymerizing resin.

Fatigue resistance of ultrathin CAD/CAM ceramic and nanoceramic composite occlusal veneers

ObjectiveThe fracture resistance of different ultrathin occlusal computer-aided design/computer-aided manufacturing (CAD/CAM) veneers was investigated under cyclic mechanical loading to restore combined enamel-dentin defects. MethodsEighty-four molars were reduced occlusally until extensive dentin exposure occurred with a remaining enamel ring. Twenty-four molars were ground flat for examination of highly standardized specimens, of which 8 were treated with uniformly flat 0.3mm IPS Empress CAD and 0.3 and 0.5mm IPS e.max CAD restorations. Sixty-four molars were anatomically prepared until dentin exposure and were restored using occlusal veneers with fissure/cusp thicknesses of 0.3/0.5mm from 3 different dental CAD/CAM materials: IPS Empress CAD, IPS e.max CAD and Lava Ultimate CAD/CAM. Teeth were etched with 37% phosphoric acid, and occlusal veneers were bonded using an adhesive luting system (Syntac Primer, Adhesive, Heliobond and Variolink II). Specimens were placed under cyclic mechanical loading in a chewing simulator (1 million cycles at 50N) and were examined for cracks after each cyclic loading sequence. The anatomical 0.3/0.5mm IPS e.max CAD specimens experienced an additional 1 million cycles at 100N. Kaplan–Meier survival curves and log-rank tests were used for data analysis. ResultsAll highly standardized and 0.3/0.5mm IPS e.max CAD specimens tolerated cyclic loading. One anatomical Lava Ultimate CAD/CAM and 10 IPS Empress CAD specimens showed cracks. SignificanceUltrathin occlusal veneers of lithium disilicate ceramic and nanoceramic composite showed remarkably high fracture strength under cyclic mechanical loading. These veneers might be a tooth substance preserving option for restoring combined dentin–enamel defects.

Effect of Decontamination and Cleaning on the Shear Bond Strength of High Translucency Zirconia.

(1) Background: This study evaluated the bonding performance of high translucency zirconia after diverse surficial decontamination and cleaning procedures. (2) Methods: High translucency zirconia (LavaTM Esthetic) specimens (2.0 mm × 20 mm × 10 mm) were exposed to different surface treatments prior to bonding to CoCr cylinders (d = 5 mm, height = 3 mm). All surfaces were sandblasted (40 µm aluminum oxide, 2 bar) and treated with alcohol (al), saliva (s), saliva + water (sw), or saliva + NaOCl + water (sn) before bonding was performed with the following adhesive luting systems: RelyXTM Unicem 2 (RX), ScotchbondTM Universal (SBU) + RelyXTM Ultimate (RU) or Monobond Plus (MP) + Multilink® Automix (ML). After 24 h, thermocycling (TC:12,000 × 5 °C/55 °C) and 90 days of storage at 37 °C in distilled water, the shear bond strength (SBS) was evaluated according to ISO/TS 11,405:2015. Failure modes along bonding areas were characterized. Means and standard deviations (n = 10 per group) were determined and statistically analyzed with one-way ANOVA/Bonferroni (α = 0.05). (3) Results: The SBS after 24 h varied between 3.5 (sRX) and 69.4 MPa (snMP + ML). Values from 0 (sRX) to 70.3 MPa (swRX) were found after TC. Data after 90 days of storage showed the lowest values for sRX (0 MPa) and the highest values for alSBU + RU (75.5 MPa). Adhesive failure was noted at all aging conditions. (4) Conclusions: SBU + RU or RX and MP + ML including saliva decontamination of the ceramic surface with water or NaOCl + water allow efficient bonding to LavaTM Esthetic.

Fracture resistance of ceramic and polymer-based occlusal veneer restorations

ObjectivesThe purpose of this in vitro study was to evaluate the influence of thermodynamic loading on the durability and fracture resistance behavior of occlusal veneers fabricated from different biomedical dental CAD/CAM materials. MethodsThe occlusal surfaces of 64 extracted premolars were prepared in the enamel layer and restored with occlusal veneers with a fissure/cusp thickness of 0.5/0.8mm made from four different dental CAD/CAM materials: group LD lithium disilicate (e.max CAD), group LS zirconia-reinforced lithium silicate (Vita Suprinity), group PI polymer-infiltrated ceramic (Vita Enamic), and group PM polymethylmethacrylate PMMA (Telio CAD). The prepared teeth were etched with phosphoric acid. The occlusal veneers were then bonded using an adhesive luting system (Multilink Primer A/B and Multilink Automix luting resin). Half of the specimens were subjected to thermodynamic loading in a chewing simulator (1.2 million cycles at 98N). All specimens were quasi-statically loaded until fracture. The statistical analysis was made using the t-test and one-way ANOVA followed by the Tukey HSD test (α = 0.05). ResultsAll aged specimens survived the thermodynamic loading. Thermodynamic loading significantly raised the fracture resistance in groups LS, PI, and PM (P < 0.03). Occlusal veneers made from lithium disilicate and zirconia-reinforced lithium silicate recorded higher fracture resistance than those made from polymer-infiltrated ceramic and PMMA resin. ConclusionsAll tested dental CAD/CAM biomaterials exhibited a fracture resistance considerably exceeding the average occlusal force in the posterior dentition. Therefore, they might present a viable long-term treatment for restoring the occlusal surfaces of posterior teeth.

The influence of intrinsic water permeation on different dentin bonded interfaces formation

ObjectivesTo determine the effects of intrinsic wetness on the formation of dentin bonding interfaces of four resin cement systems bonded to dentin under different pulpal pressures. MethodsThirty-six freshly extracted third molars were selected and processed for dentin μTBS. The teeth were randomly assigned into 12 experimental groups, according to the adhesive luting system [Adper Single Bond Plus (3M ESPE) combined with two luting agents RelyX ARC (3M ESPE) and heated Filtek Z250 Universal Restorative (3M ESPE), Clearfil CD Bond (Kuraray) combined with Clearfil Esthetic Cement (Kuraray), and RelyX Unicem 2 Automix (3M ESPE)] and pulpal pressure (0, 5, and 20cm of simulated pulpal pressure). Leucite-reinforced glass-ceramic slabs (IPS Empress CAD, Ivoclar Vivadent) of 3mm thickness were bonded to dentin. The samples were stored in distilled water for 24h and then sectioned in X/Y directions across the adhesive interface to obtain specimens with a cross section of 0.8±0.2mm2. All sticks were fractured by tension at a crosshead speed of 1.0mm/min and the data were submitted to Kruskal-Wallis and Mann-Whitney Tests (α=0.05). Ultrastructural analysis of the interfaces was performed using Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscopy (SEM). ResultsThe statistical analyses showed that pulpal pressure decreased μTBS for all groups. Significantly higher μTBS values were obtained in heated Z250 group restored without any pulpal pressure. CLSM showed that the uptake of water through the dentin tubuli and their anastomosis of lateral branches during the adhesive luting procedures prevented adequate formation of the dentin bonding interfaces. SEM showed that the luting film created is material- dependent and all adhesive failure occurred at the resin-dentin interface. ConclusionThe constant intrinsic wetness replenishment prevents adequate formation of the hybrid layer. Clinical significanceIntrinsic moisture during adhesive luting procedures significantly affects the interaction between luting materials and dentin subtract and decreases the quality and bonding strength of the resin-dentin bond.

3D quantification of clinical marginal and internal gap of porcelain laminate veneers with minimal and without tooth preparation and 2-year clinical evaluation.

The aims of this clinical study were to compare internal three-dimensional (3D) adaptation of porcelain laminate veneers (PLV) with minimal tooth preparation and without tooth preparation (prepless) and to evaluate the clinical outcomes at baseline and following 6, 12, and 24 months after luting. Thirty-one prepless PLV and 31 PLV with minimal tooth preparation were fabricated using lithium disilicate glass-ceramic material and placed in 12 patients (8 women, 4 men; 18 to 40 years old). All PLV were luted with an adhesive luting system (Variolink veneer). A silicone replica was obtained to measure internal adaptation of each PLV using a low viscosity polyvinyl siloxane impression material just before luting. Silicone replicas were scanned in x-ray micro computerized tomography (micro CT). Clinical evaluations took place at baseline (2 days after luting) and following 6, 12, and 24 months after luting. Marginal integrity, marginal discoloration, secondary caries, tooth sensitivity, and fracture were evaluated following FDI criteria. Replica scores were analyzed using Mann-Whitney U and Student's t test (α = .05). Kaplan-Meier statistical analysis was done for the survival rate of PLV. FDI criteria scores were analyzed using Pearson's chi-square test (α = .05). The median marginal gaps for PLV-without-tooth-preparation and PLV-with-minimal-tooth-preparation groups were 100 μm and 140 μm respectively. There was a statistically significant difference between the two groups with respect to marginal gap (P = .04). The mean internal adaptation for the PLV-without-tooth-preparation group was 217.17 ± 54.72 μm, and was 170.67 ± 46.54 μm for the PLV-with-minimaltooth- preparation group. There was a statistically significant difference between the two groups (P = .001). Based on FDI criteria, 100% of the PLV were rated satisfactory during the 2-year period. In this in-vivo study, mean and median values of marginal gap and internal adaptation for PLV with minimal tooth preparation and PLVs without tooth preparation were within a clinically acceptable range. A 100% success rate was recorded for all PLV during the 2-year period.

The effect of silane applied to glass ceramics on surface structure and bonding strength at different temperatures.

PURPOSETo evaluate the effect of various surface treatments on the surface structure and shear bond strength (SBS) of different ceramics.MATERIALS AND METHODS288 specimens (lithium-disilicate, leucite-reinforced, and glass infiltrated zirconia) were first divided into two groups according to the resin cement used, and were later divided into four groups according to the given surface treatments: G1 (hydrofluoric acid (HF)+silane), G2 (silane alone-no heat-treatment), G3 (silane alone-then dried with 60℃ heat-treatment), and G4 (silane alone-then dried with 100℃ heat-treatment). Two different adhesive luting systems were applied onto the ceramic discs in all groups. SBS (in MPa) was calculated from the failure load per bonded area (in N/mm2). Subsequently, one specimen from each group was prepared for SEM evaluation of the separated-resin–ceramic interface.RESULTSSBS values of G1 were significantly higher than those of the other groups in the lithium disilicate ceramic and leucite reinforced ceramic, and the SBS values of G4 and G1 were significantly higher than those of G2 and G3 in glass infiltrated zirconia. The three-way ANOVA revealed that the SBS values were significantly affected by the type of resin cement (P<.001). FIN ceramics had the highest rate of cohesive failure on the ceramic surfaces than other ceramic groups. AFM images showed that the surface treatment groups exhibited similar topographies, except the group treated with HF.CONCLUSIONThe heat treatment was not sufficient to achieve high SBS values as compared with HF acid etching. The surface topography of ceramics was affected by surface treatments.

Shear bond strength of porcelain laminate veneers to enamel, dentine and enamel–dentine complex bonded with different adhesive luting systems

Shear bond strength of porcelain laminate veneers to enamel, dentine and enamel–dentine complex bonded with different adhesive luting systems

Shear bond strength of porcelain laminate veneers to enamel, dentine and enamel–dentine complex bonded with different adhesive luting systems

ObjectivesThe aim of this study was to evaluate the shear bond strength of porcelain laminate veneers to 3 different surfaces by means of enamel, dentine, and enamel–dentine complex. MethodsOne hundred thirty-five extracted human maxillary central teeth were used, and the teeth were randomly divided into 9 groups (n=15). The teeth were prepared with 3 different levels for bonding surfaces of enamel (E), dentine (D), and enamel–dentine complex (E–D). Porcelain discs (IPS e.max Press, Ivoclar Vivadent) of 2mm in thickness and 4mm in diameter were luted to the tooth surfaces by using 2 light-curing (RelyX Veneer [RV], 3M ESPE; Variolink Veneer [VV], Ivoclar Vivadent) and a dual-curing (Variolink II [V2], Ivoclar Vivadent) adhesive systems according to the manufacturers’ instructions. Shear bond strength test was performed in a universal testing machine at 0.5mm/min until bonding failure. Failure modes were determined under a stereomicroscope, and fracture surfaces were evaluated with a scanning electron microscope. The data were statistically analysed (SPSS 17.0) (p=0.05). ResultsGroup RV-D exhibited the lowest bond strength value (5.42±6.6MPa). There was statistically no difference among RV-D, V2-D (13.78±8.8MPa) and VV-D (13.84±6.2MPa) groups (p>0.05). Group VV-E exhibited the highest bond strength value (24.76±8.8MPa). ConclusionsThe type of tooth structure affected the shear bond strength of the porcelain laminate veneers to the 3 different types of tooth structures (enamel, dentine, and enamel–dentine complex). Clinical significanceWhen dentine exposure is necessary during preparation, enough sound enamel must be protected as much as possible to maintain a good bonding; to obtain maximum bond strength, preparation margins should be on sound enamel.

Durability of four composite resin cements bonded to dentin under simulated pulpal pressure

Objectives This study aimed to investigate the durability of four adhesive luting systems bonded to dentin with and without simulated hydrostatic pulpal pressure (PP). Methods Composite blocks were bonded to dentin with four adhesive systems: Multilink Automix (MA), Multilink Sprint (MS), Clearfil Esthetic cement (CE) and RelyX ARC (RAC) under either a PP of 0 or 15 cm H 2O. After 3 d water storage at 37 °C or thermal cycling (TC), of 30 d with 5000 TC or 90 d with 15,000 TC micro-tensile bond strength (μTBS) was tested. Failure analysis of the bonding interface was performed using a scanning electron microscope (SEM). Results Independent of PP application groups MA and RAC showed significantly higher μTBS than CE and MS ( P ≤ 0.05). A significant decrease in μTBS was found for RAC and MS when subjected to PP ( P ≤ 0.05), whereas CE and MA showed no significant difference ( P > 0.05). TC had no significant influence on the μTBS in RAC, MA and CE without PP application ( P > 0.05), whereas CE with PP and MS showed a significant decrease in μTBS ( P ≤ 0.05) when subjected to TC. Significance Based on these results, there were significant differences between materials. Pulpal pressure and artificial aging also seem to have an effect on in-vitro evaluation of bonding durability. If considered relevant to the materials’ service performance then these conditions should be applied in the materials’ testing.

Marginal adaptation of three self-adhesive resin cements vs. a well-tried adhesive luting agent

This in vitro study compared the marginal adaptation of three self-adhesive composite cements with the clinically well-tried dentin adhesive system Panavia F 2.0. A total of 32 Empress 2 all-ceramic MOD-inlays (eight in each group) were luted using the self-adhesive composite cements Maxcem, Multilink Sprint, and RelyX Unicem Clicker; Panavia F 2.0 served as a clinically well-tried control. Each luted inlay underwent long-term water storage of 90 days as well as additional mechanical and thermal loading to simulate oral service. Marginal integrity was evaluated in both dentin and enamel finishing lines using scanning electron microscopy (SEM) and dye penetration tests. Dye penetration was lowest for Panavia followed by RelyX Unicem. Maxcem and Multilink showed a considerable dye penetration of up to 60%. After aging, SEM analysis revealed a reduction of "perfect margin" areas for Multilink Sprint and RelyX Unicem in enamel and for Maxcem and Multilink in dentin. Compared with the well-tried system Panavia--which was assumed as the golden standard of adhesive luting systems--only the self-adhesive luting agent RelyX Unicem showed similar results of marginal adaptation after long-term water storage.

The Influence of Adhesive Luting Systems on Bond Strength and Failure Mode of an Indirect Micro Ceramic Resin-based Composite Veneer

This study evaluated the bond strength and failure mode of enamel/resin-based composite veneers bonded with three different dual cured resin adhesive systems. Standard preparations for laminate veneer restorations were made on 30 human central incisors using depth cutting burs (0.5 mm depth at the incisal area and 0.3 mm at the gingival area). Thirty indirect laminates were prepared using a highly filled polymeric material (GC Gradia) according to the manufacturer's instructions. After sandblasting the fitting surfaces, the specimens were randomly divided into three groups (ten per group) based on the type of resin cement luting systems; Excite/Variolink II, Single Bond/Rely X Veneer Cement, and Clearfil New Bond/Panavia F. The specimens were stored in water at 37 degrees C for 48 hours. Fracture testing was performed using a universal testing machine where the load was applied from the incisal direction at 135 degrees to the long axis of the tooth (0.5 mm/min). The one-way analysis of variance (ANOVA) and Chi-Square tests were used for statistical analysis at a significance level of p > 0.05. The ANOVA showed no significant difference was found among the groups (P > 0.05). Indirect veneers showed mean enamel bond strength of 114.4 +/- 48 N, 159.7 +/- 83.4 N, and 126.1 +/- 51.7 N with Variolink II, Rely X veneer cement, and Panavia F, respectively. The Chi-Square tests showed no significant difference regarding the failure mode frequencies in different types of failure in the three groups (p>0.05). The failure mode analysis showed mainly adhesive failure in the resin cement/laminate interface in all groups. There was no significant difference in bond strength of veneers with the three different resin cements tested. In addition, there was no significant difference in the frequency of the failure mode in each type of failure among the three test groups. The failure analysis revealed mainly an adhesive failure at the resin cement/veneer interface. The results of this study suggest the use of Excite/Variolink, Single Bond/RelyX, or Clearfil New Bond/Panavia F are all appropriate choices for luting of indirect micro ceramic resin-based composite veneers in terms of bond strength and failure mode.

Bond strength of glass–ceramics on the fluorosed enamel surfaces

Objectives Effect of different adhesive luting systems on the shear bond strength of IPS Empress 2 ceramic restorations to fluorosed enamel surface was investigated. Methods Forty-eight ceramic discs (2 mm × 3 mm; IPS Empress 2) were fabricated. Twenty-four non-carious extracted human molar teeth with fluorosis and 24 without fluorosis were cleaned with pumice using a plastic brush and then they were divided into two main groups. The IPS Empress 2 ceramic discs were luted to the teeth of four subgroups with two different adhesive luting systems, Variolink 2/Excite DSC (etch-and-rinse) and Clearfil Esthetic Cement/ED Primer II (self-etch), thermocycling was performed 5000 times. Shear bond strengths were tested using Shimadzu Universal Testing Machine until failure. An optical microscope and image analyzer were used at 10× and 1000× magnification to analyze the surfaces for adhesive, cohesive and mixed failure percentages. Data was analyzed with one-way ANOVA and Tukey test at a significance level of p < 0.05. Results Mean shear bond strength data of the groups in MPa were; Variolink 2/Excite DSC on fluorosed enamel: 18.3 ± 3.08, Variolink 2/Excite DSC on non-fluorosed enamel: 18.79 ± 2.65, Clearfil Esthetic Cement/ED Primer II on fluorosed enamel: 8.43 ± 2.45, Clearfil Esthetic Cement/ED Primer II on non-fluorosed enamel: 13.53 ± 1.68. Mixed failure was the most prevalent type of failure in moderate fluorosed and non-fluorosed teeth with etch-and-rinse dentin bonding system, and in fluorosed teeth with self-etch dentin bonding system. Conclusions The use of an etch-and-rinse adhesive luting procedure produced higher bond strengths of glass–ceramics bonded to fluorosed and non-fluorosed enamel surfaces than the self-etch bonding system.

Influence of light-activated and auto- and dual-polymerizing adhesive systems on bond strength of indirect composite resin to dentin

Clinicians must be aware of the bonding effectiveness of auto- and dual- polymerizing adhesive systems before choosing the material and technique of cementing inlay/onlays to dentin. An inadequate choice may compromise the success of indirect restorations. This study compared the microtensile bond strength (MTBS) of indirect composite resin bonded to dentin by light-activated, autopolymerizing, and dual-polymerizing adhesive systems. Occlusal dentin surfaces of 36 human third molars were exposed and flattened. Teeth were assigned to 1 of the following 6 groups (n=6) of adhesive luting systems: 2 dual-polymerizing systems (Scotchbond Multipurpose Plus/Rely X [SBMP] and Prime & Bond NT Dual Cure/Enforce [PBDC]); 1 autopolymerizing system (ED Primer/Panavia F [EDP]); and 3 light-activated systems (control groups) (Adper Single Bond/Rely X [SB], Prime & Bond NT/Enforce [PB], and Clearfil SE Bond/Panavia F [CF]). The restorative materials were applied according to manufacturer's directions. A 2-mm-thick prepolymerized composite resin (Clearfil APX) disc was cemented with the resin cements on the bonded dentin. Teeth were stored in water at 37 degrees C for 24 hours. Afterwards, teeth were sectioned both mesial-distally and buccal-lingually to obtain multiple bonded beam specimens with 0.8 mm(2) of cross-sectional area. Each specimen was tested in tension at a crosshead speed of 0.5 mm/min until failure. Data (MPa) were analyzed by 1-way analysis of variance and the Tukey post hoc test (alpha=.05). Failure patterns of tested specimens were analyzed using scanning electron microscopy. Mean MTBS values (MPa) for experimental groups were as follows: SBMP, 32.89 +/- 3.26(a); SB, 26.74 +/- 7.45(ab); PB, 26.11 +/- 4.48(ab); CF, 25.30 +/- 6.42(ab); EDP, 16.82 +/- 5.53(bc); PBDC, 11.20 +/- 5.89(c) (P<.001). Groups with similar lowercase letters were not significantly different. Failure pattern of fractured specimens varied according to the polymerization mode. The autopolymerizing system and one of the dual-polymerizing systems were as effective as the light-activated systems in bonding indirect composite restorations to dentin.

A comparative study of marginal microleakage using three different cements in ceramic crowns

OBJECTIVE: To evaluate the marginal microleakage of IPS-Empress 2 all-ceramic crowns using three different cements. METHODS: Twenty-four IPS-Empress 2 all-ceramic crowns were built and luted onto standardly prepared human upper third molars using three different cements. All samples were thermocycled then submerged in 2% fuchsin for 24 hours. The marginal microleakage at tooth-cement and ceramic crown-cement interfaces was observed using light stereomicroscopy. RESULTS: The Panavia F adhesive luting system demonstrated the least microleakage(0.90+/-0.75, 0.46+/-0.37). Dyract compomer cement showed an intermediate level of microleakage (4.71+/-1.68, 5.28+/-1.48). Harvard zinc phosphate cement was associated with severe microleakage in all specimens( 6.99+/-0.04, 6.99+/-0.04). THe differences in microleakage among the three cements was highly significant(P<0.01). CONCLUSION: Panavia F adhesive luting system was the most effective dental cement to prevent microleakage. It can be used for IPS-Empress 2 posterior all-ceramic crowns.