Effect of the dentin cleansing techniques on dentin wetting and on the bond strength of a resin luting agent

STATEMENT OF PROBLEM: Remnants of the provisional cement on prepared teeth may have an adverse effect on the performance of the definitive luting agent. PURPOSE: This in vitro study investigated the effect of different dentin cleansing techniques on the bond strength of a resin luting agent and dentin wetting. MATERIAL AND METHODS: Sixty buccal or lingual coronal portions of human molar teeth were mounted, with the buccal or lingual surfaces up, in acrylic resin blocks. The specimens were prepared until the dentin was exposed and a eugenol-containing provisional cement (Temp Bond) was applied to the dentin surfaces. After mechanical removal of the cement with a carving instrument, specimens were divided into 6 groups of 10 specimens each. The dentin surfaces of the specimens were treated with 1 of 5 cleansing techniques: Group S, cleansing agent (Sikko Tim); Group C, cleansing agent (Cavity Cleanser); Group O, rotary instrumentation (OptiClean); Group OS, rotary instrument preceding Sikko Tim; and Group OC, rotary instrumentation preceding Cavity Cleanser. The remaning 10 specimens were untreated and served as controls (CT). An adhesive resin luting agent (Variolink II) was applied to all specimens. Shear bond strength (MPa) was measured using a universal testing machine at a 0.5 mm/min crosshead speed. To measure the contact angle, another 6 groups (n=5) were prepared using the same methods. Contact angle measurements were performed to assess wettability using the Axisymmetric Drop Shape Analysis-Contact Diameter (ADSA-CD) technique. Wettability measurements were made with water. Data were statistically analyzed by 1-way analysis of variance with Tukey HSD tests (alpha=.05). The effect of the dentin cleansing techniques on removing the provisional cement from the dentin surface was examined with scanning electron microscope (SEM). RESULTS: Specimens cleaned with all techniques showed stronger shear bond strength values than control specimens (P<.001), with the exception of C specimens. The surface cleansing techniques tested affected the dentin wetting significantly in comparison with the control group (P<.001), except for the C and the O groups. There was no significant difference in wetting between the groups C and O. The SEM observations demonstrated that the dentin cleansing techniques left differing amounts of provisional cement remnants. CONCLUSION: Specimens treated with only the cleansing agent Sikko Tim showed the highest bond strength, likely due to the solvent effect of Sikko Tim on the removal of provisional cement. The lowest bond strength was obtained with the rotary instrument. It was concluded that the provisional cement could plug the dentinal tubules into which the resin luting agent penetrates.     

TREE牙齿美白胶对牙本质与树脂粘接强度影响的实验研究

目的:比较牙本质经TREE牙齿美白胶漂白后,在不同时间粘接树脂的抗剪强度变化及粘接界面超微形态。方法:18颗恒前磨牙随机分为3组。A组:人工唾液内储存3周后制备牙本质粘接面,粘接树脂。B组:牙齿漂白3周后制备牙本质粘接面,粘接树脂;C组:牙齿漂白3周,人工唾液内储存2周后制备牙本质粘接面,粘接树脂。万能材料实验机测量抗剪强度;扫描电镜观察粘接界面超微形态。结果:抗剪强度:B组(10.74±3.03)MPa与A组(18.61±3.56)MPa及C组(17.21±3.15)MPa有明显差异(均为P<0.05),而A与C组无差异(P>0.05)。粘接界面超微形态:B组树脂突稀少,长度较短并且长短不一。A组与C组树脂突多,但C组树脂突较A组的短小。结论:牙齿经TREE牙齿美白胶漂白后即刻粘接树脂,会降低牙本质与树脂的粘接强度,延迟2周再粘接树脂能够恢复粘接强度。     

Efficacy of various cleansing techniques on dentin wettability and its influence on shear bond strength of a resin luting agent

PURPOSE

To evaluate the shear bond strength of resin luting agent to dentin surfaces cleansed with different agents like pumice, ultrasonic scaler with chlorhexidine gluconate, EDTA and the influence of these cleansing methods on wetting properties of the dentin by Axisymmetric drop Shape Analysis - Contact Diameter technique (ADSA-CD).

MATERIALS AND METHODS

Forty coronal portions of human third molar were prepared until dentin was exposed. Specimens were divided into two groups: Group A and Group B. Provisional restorations made with autopolymerizing resin were luted to dentin surface with zinc oxide eugenol in Group A and with freegenol cement in Group B. All specimens were stored in distilled water at room temperature for 24 hrs and provisional cements were mechanically removed with explorer and rinsed with water and cleansed using various methods (Control-air-water spray, Pumice prophylaxis, Ultrasonic scaler with 0.2% Chlorhexidine gluconate, 17% EDTA). Contact angle measurements were performed to assess wettability of various cleansing agents using the ADSA-CD technique. Bond strength of a resin luting agent bonded to the cleansed surface was assessed using Instron testing machine and the mode of failure noted. SEM was done to assess the surface cleanliness. Data were statistically analyzed by one-way analysis of variance with Tukey HSD tests (α=.05).

RESULTS

Specimens treated with EDTA showed the highest shear bond strength and the lowest contact angle for both groups. SEM showed that EDTA was the most effective solution to remove the smear layer. Also, mode of failure seen was predominantly cohesive for both EDTA and pumice prophylaxis.

CONCLUSION

EDTA was the most effective dentin cleansing agent among the compared groups.     

Effect of surface preparation on bond strength of resin luting cements to dentin

This study examined the effects of using two different burs for dentin surface preparation on the microtensile bond strength (microTBS) of three resin luting cements. Flat, deep dentin surfaces from 45 extracted human third molars were divided into three groups (n = 15) according to bur type: (i) diamond bur and (ii) tungsten carbide bur. The controls were abraded with #600-grit SiC paper. Both burs operated in a high-speed handpiece under water-cooling. Composite blocks were luted onto the dentin using one of three cements: RelyX ARC (ARC, 3M ESPE), Panavia F2.0 (PF, Kuraray) and RelyX Unicem (UN, 3M ESPE) following the manufacturers' instructions. For ARC, the dentin surface was treated with 32% phosphoric acid. The bonded specimens were stored at 37 degrees C for 24 hours and sectioned into 0.9 x 0.9 mm beams for microTBS testing. The data were analyzed using the two-way ANOVA and Student-Newman-Keuls tests. Representative fractured beams from each group were prepared for fractographic analysis under SEM. Two-way ANOVA revealed that the effects of "dentin surface preparation" and "luting cement" were statistically significant (p < 0.001); however, the interaction of these two factors was not significant (p > 0.05). ARC showed no significant difference in microTBS among the three differently prepared dentin surfaces. The microTBS of PF and UN was significantly lower when bonding to dentin prepared with a diamond bur (p < 0.05), compared to the control. For Panavia F2.0, higher bond strengths were achieved on the dentin surface prepared with a tungsten carbide bur. Proper bur selection is essential to optimizing the dentin adhesion of self-etch resin luting cements.     

Effect of saliva contamination on bond strength of resin luting cements to dentin

Objectives

This study examined the effect of saliva contamination on the microtensile bond strength (μTBS) of resin luting cements to dentin.

Methods

For RelyX ARC (ARC, 3M ESPE), dentin surfaces were etched with 32% phosphoric acid. The subgroups were: ARC-control (uncontaminated), ARC-I (saliva contamination, blot-dried), ARC-II (saliva contamination, rinse, blot-dried) and ARC-III (saliva contamination, rinse, re-etch, rinse, blot-dried). For Panavia F 2.0 (PF, Kuraray), the subgroups were: PF-control (uncontaminated), PF-I (saliva contamination, dried), PF-II (saliva contamination, rinse, dried), PF-III (primer, saliva contamination, dried), PF-IV (primer, saliva contamination, dried, primer re-applied) and PF-V (primer, saliva contamination, rinse, dried, primer re-applied). Composite blocks were luted onto dentin using the two cements. Bonded specimens were sectioned into 0.9 mm × 0.9 mm beams for μTBS testing. Representative fractured beams were prepared for fractographic analysis.

Results

For ARC, salivary contamination of etched dentin (ARC-I) significantly lowered bond strength (p = 0.001). Rinsing saliva off with water (ARC-II) restored bond strength to control level. Re-etching dentin surface after rinsing (ARC-III) resulted in the lowest bond strength (p < 0.001). For PF, salivary contamination of dentin before (PF-I) and after application of primer (PF-III and PF-IV) significantly lowered bond strength (p < 0.001). Rinsing saliva off with water and re-application of primer (PF-II and PF-V) improved bond strength.

Conclusion

Saliva contamination during luting deteriorated the bond quality of resin cements. Decontamination by rinsing with water was most effective in restoring the bond strength of RelyX ARC. Decontamination by water-rinsing and primer re-application after rinsing improved the bond strength of Panavia F 2.0.     

Effect of surface treatment and luting agent type on shear bond strength of titanium to ceramic materials

PURPOSEThis study aimed to compare the effect of different surface treatments and luting agent types on the shear bond strength of two ceramics to commercially pure titanium (Cp Ti).MATERIALS AND METHODSA total of 160 Cp Ti specimens were divided into 4 subgroups (n = 40) according to surface treatments received (control, 50 µm airborne-particle abrasion, 110 µm airborne-particle abrasion, and tribochemical coating). The cementation surfaces of titanium and all-ceramic specimens were treated with a universal primer. Two cubic all-ceramic discs (lithium disilicate ceramic (LDC) and zirconia-reinforced lithium silicate ceramic (ZLC)) were cemented to titanium using two types of resin-based luting agents: self-cure and dual-cure (n = 10). After cementation, all specimens were subjected to 5000 cycles of thermal aging. A shear bond strength (SBS) test was conducted, and the failure mode was determined using a scanning electron microscope. Data were analyzed using three-way ANOVA, and the Tukey-HSD test was used for post hoc comparisons (P < .05).RESULTSSignificant differences were found among the groups based on surface treatment, resin-based luting agent, and ceramic type (P < .05). Among the surface treatments, 50 µm air-abrasion showed the highest SBS, while the control group showed the lowest. SBS was higher for dual-cure resin-based luting agent than self-cure luting agent. ZLC showed better SBS values than LDC.CONCLUSIONThe cementation of ZLC with dual-cure resin-based luting agent showed better bonding effectiveness to commercially pure titanium treated with 50 µm airborne-particle abrasion.     

不同树脂粘固剂对瓷与牙本质粘接强度的比较研究

目的 评价不同种类树脂粘固剂与瓷-牙本质粘接强度的差异,以期为临床提供参考.方法选取无龋坏青年人前磨牙制备牙本质粘接面,铸造直径为3 mm、高为3 mm的圆柱状瓷块(IPS e.max Press)80个,分为A、B、C、D、E 5组.分别选用树脂粘固剂A(Variolink Ⅱ)、B(MultilinkAutomix)、C(Multilink Sprint)、D(Rely X Unicem)和E(BisCem)将瓷块粘固于牙本质粘接面上,每组制成16个试样.37℃水储24 h后每组8个试样直接测试剪切粘接强度,另8个试样进行5000次冷热循环后测试粘接强度,扫描电镜观察粘接面形态.对同种粘固剂冷热循环前后的粘接强度进行双样本t检验.结果冷热循环前A组粘接强度[(22.3±3.9)MPa]最大,B组[(18.1±3.5)MPa]次之,再次为D组[(14.1±2.3)MPa]和E组[(11.7±4.2)MPa],C组[(11.3±3.6)MPa]最小.冷热循环后A组粘接强度[(17.8±2.3)MPa]仍最大,B组[(14.4±3.5)MPa]和D组[(13.2±2.5)MPa]次之,再次为E组[(8.9±3.2)MPa],C组[(7.0±2.4)MPa]最小.与冷热循环前相比,冷热循环后A、B、C 3组粘接强度均下降,差异有统计学意义(P<0.05);D组和E组粘接强度下降不明显(P>0.05).结论以全酸蚀粘接技术为基础的树脂粘固剂的粘接强度大于以自酸蚀粘接技术为基础的树脂粘固剂和自粘接型树脂粘固剂.     

Influence of ceramic thickness and polymerization mode of a resin luting agent on early bond strength and durability with a lithium disilicate-based ceramic system

STATEMENT OF PROBLEM: Attenuation of polymerization light energy by translucent all-ceramic materials may result in insufficient polymerization of underlying resin luting agents and inadequate early bond strength and durability. There is little information regarding the selection of an appropriate polymerization mode for cementing translucent all-ceramic restorations. PURPOSE: The purpose of this study was to evaluate the influence of ceramic thickness and polymerization mode on the early bond strength and bond durability of a lithium disilicate-based ceramic system. MATERIAL AND METHODS: The occlusal surfaces of 120 extracted, intact, human third molars were sectioned to expose a flattened area of dentin. The surface was etched with 32% phosphoric acid, and a single-step adhesive (One-Step) was applied to the etched dentin surfaces. Ceramic specimens (Empress 2), 6 mm in diameter and 1 mm, 1.5 mm, or 2 mm thick (n=40 per group), were fabricated using fluoropolymer resin matrixes. Each specimen was ground flat. Following hydrofluoric acid etching and silane treatment, ceramic discs of each thickness were further divided into 2 groups (n=20 per group) and bonded to the dentin surfaces with a dual-polymerized resin luting agent (Illusion), either with a catalyst (dual polymerization) or without a catalyst (light polymerization). A shear bond test was performed after 10 minutes (n=10) or after 24 hours following 1000 thermal cycles between 5 degrees C and 55 degrees C and a dwell time of 30 seconds (n=10). Debonded dentin surfaces were examined with SEM. The data were analyzed with 3-way analysis of variance (ANOVA) (alpha=.05). RESULTS: The shear bond strengths ranged between 13.2 +/- 4.1 MPa and 15.9 +/- 2.0 MPa. Three-way ANOVA revealed that ceramic thickness, polymerization mode, storage time, or combinations of these parameters did not influence shear bond strength. The location of failure for all specimens was adhesive, between the dentin surface and bonding agent. CONCLUSION: Both light polymerization and dual polymerization provided similar early shear bond strengths for the lithium disilicate-based ceramic system (Empress 2). The bond strength was not dependent on the thickness of the ceramic material tested. Durability of the bond was similar for both of the polymerization modes.     

In vitro shear bond strength of resin-based luting cements to dentin

The aim of this study was to determine how resin cement, self-adhesive resin cement, and resin-modified glass ionomer cement affected shear bond strength to dentin. Sixty composite resin disks (3 mm in diameter x 3 mm in length) were prepared and divided into four groups (n = 15): Group 1, composite disk bonded to dentin with composite resin and a bonding agent; Group 2, composite disk bonded to dentin with a self-adhesive resin cement; Group 3, composite disk bonded to dentin with a different self-adhesive resin cement; and Group 4, composite disk bonded to dentin with a resin-modified glass ionomer cement. The composite resin was loaded into a syringe (internal diameter 3 mm), photocured in an oven, and cut into 3 mm slices with a low-speed saw. The samples were bonded to dentin per the manufacturer's instructions. All specimens were stored in distilled water (at 37 degrees C) for 24 hours. The shear bond strength test was conducted using a universal testing machine at a crosshead speed of 0.5 mm/min until failure. Conventional resin cement and a bonding agent exhibited significantly higher shear bond strength values than all other materials tested.     

Effect of thermocycling on the bond strength of a glass-infiltrated ceramic and a resin luting cement

The aim of the present study was to evaluate the effect of thermocycling on the bond strength between the surface of the glass-infiltrated alumina ceramic In-Ceram (VITA) and the Panavia F resin cement (Kuraray CO.). Four 5x6x6mm In-Ceram blocks were obtained. One of the 6x6mm faces of each block was conditioned with Cojet - System (tribochemical silica coating, ESPE-3M) and then luted under a constant 750g pressure with Panavia F cement to another identical face of a resin composit block (Clearfil AP-X, Kuraray) obtained by reproduction of the ceramic one from Express (3M) addition curing silicone impressions. The four sets so formed by ceramic, luting cement and resin have been each one serially sectioned in 20 sticks so that the adhesive surface in each presented 1mm2 of area. The samples were divided in 2 groups (n=10): G1- stored for 7 days in deionized water at 36 ± 2oC; G2 - thermocycled 1500 times between 5 and 55oC dwell times. The microtensile tests were accomplished in an universal testing machine (EMIC) at a crosshead speed of 0,5 mm/min. The results showed that the mean tensile bond strength values (MPa) for the group G2: (22,815 ± 5,254) had not statistically differ of the values of group G1: (25,628 ± 3,353) (t = 1,427; gl = 18; p-value = 0,171), at the level of a= 5%. It can be concluded that the thermocycling technique used in the present experiment had not produced statistically significant differences between the bond strength results of the specimens obtained by the two used techniques.     

Effect of pulpal pressure on the microtensile bond strength of luting resin cements to human dentin

ObjectivesThe objectives of this study were to examine the effect of pulpal pressure on the microtensile bond strength (mTBS) of luting resin cements to human dentin and the permeability of dentin surfaces pre-treated with an adhesive and a self-etching primer.MethodsCylindrical composite blocks were luted with resin cements (RelyX ARC, 3M ESPE: ARC; Panavia F, Kuraray Medical Inc.: PF; RelyX Unicem, 3M ESPE: UN) in the absence or presence of simulated pulpal pressure. The application of Adper Single Bond 2 (3M ESPE) and ED primer 2.0 (Kuraray) was performed under 0 cm H₂O. After each resin cement was applied, the pulpal pressure group was subjected to 20 cm H₂O of hydrostatic pressure for 10 min during the initial setting period. Testing for mTBS was performed on 0.9 mm × 0.9 mm sectioned beams after 24 h water-storage. Scanning electron microscopy was performed to investigate the fractured surfaces after mTBS testing and additional dentin surfaces that were treated by an etchant, ED primer 2.0 and UN. Fluid permeability was measured on dentin surfaces that were applied with Adper Single Bond 2 and ED primer 2.0.ResultsApplication of pulpal pressure reduced mTBS significantly in groups ARC and PF. Porous bonding interfaces due to water permeability through the cured adhesive were observed on fractured surfaces. Dentin surfaces that were applied with the adhesive and the primer were more permeable than smear layer-covered dentin. The mTBS of UN was significantly lower than ARC and PF regardless of the absence/presence of pulpal pressure.SignificanceFluid permeation during the initial setting period deteriorated the bonding quality of resin cements.     

过硼酸钠内漂白对牙本质与树脂粘接强度影响的实验研究

目的比较牙本质经过硼酸钠漂白后在不同时间粘接树脂,其抗剪强度变化及粘接界面的超微形态。方法18颗恒前磨牙随机分为3组。A组为对照组：人工唾液内3周后制备牙本质粘接面,粘接树脂。B组：牙齿漂白3周后制备牙本质粘接面,粘接树脂;C组：牙齿漂白3周,人工唾液内储存2周后制备牙本质粘接面,粘接树脂。电子万能材料实验机测试抗剪粘接强度;扫描电镜观察粘接界面超微形态。结果①抗剪强度测试结果：A组：18.61±3.56MPa;B组：12.10±2.64MPa;C组：16.78±2.84MPa。②统计学分析：单因素方差分析表明三组样本均数之间存在统计学差异（P〈0.05）。各样本均数的两两比较（SNK-q法）结果显示A与B组,B与C组的抗剪强度值差别有统计学意义（P〈0.05）,而A与C组的抗剪强度值之间无统计学差异（P〉0.05）。③粘接界面的SEM观察结果：A组粘接界面上可见大量的树脂突渗入牙本质小管内,树脂突的长度较长并且均匀。B组粘接界面上的树脂突稀少,长度较短并且长短不一。C组粘接界面可见有较多的树脂突,长度均匀但较为短小。结论过硼酸钠漂白后牙本质的粘接时间对牙本质与树脂的粘接强度有影响：牙齿漂白后即刻粘接树脂,会降低牙本质与树脂的粘接强度,而漂白后延迟2周再粘接树脂能够恢复牙本质与树脂的粘接强度。     

The effects of luting resin bond to dentin on the strength of dentin supported by indirect resin composite.

OBJECTIVES: The purpose of this study was to evaluate the effects of thickness and adhesion of three resin cements on the fracture resistance of indirect resin composite bonded to dentin. METHODS: A disk of resin composite used for indirect restorations was bonded to a disk of bovine dentin using three kinds of resin cements with various bonding procedures. The bonding procedures were planned into five groups according to the materials and methods, and subsequently subdivided into three groups according to the cement thickness (50, 150 and 500 microm) in each bonding procedure. The thickness of the resin cement and that of the resin composite disk was changed simultaneously while maintaining a total specimen thickness of 2 mm. The prepared specimens were then stored in water at 37 degrees C for 24h at which time they were trimmed to a size of 2 x 2 x 8 mm. The trimmed specimens were subjected to a three point bending test and the fracture load determined. The tensile bond strength of each bonding procedure was measured and the correlation to the fracture load evaluated. RESULTS: The fracture load was affected by the dentin bond strength. The effect of cement film thickness on the fracture load was negligible. SIGNIFICANCE: When an indirect restoration is adhered to the tooth substrate, the adhesion of the luting cement to the tooth substrate is very important for the fracture resistance of indirect resin composite.     

The influence of convergence angle and dentin micromorphology on shear bond strength of adhesive resin luting cement

PURPOSE: To determine the influence of convergence angles and axial planes on shear bond strength between dentin and adhesive composite resin luting cement, and its relation to dentin micromorphology. MATERIALS AND METHODS: The four axial planes of 60 intact extracted mandibular molars were prepared at either 4 or 20 degrees to the longitudinal tooth axis. A Teflon cylindrical mold (1.6 mm) was filled with Rely X-ARC, bonded to Single Bond treated dentin surface and tested for shear bond strength after 7 days. Three SEM micrographs (5000X magnification) were taken from each surface after removing the bonding layer. The tubule circumference was marked using Adobe Photoshop. Micromorphology parameters were analyzed with the MATLAB program. A Mixed Effect Linear Model and linear regression were performed to analyze the influence of tubule density, tubule area, tubule circumference, and residual dentin thickness on shear bond strength. RESULTS: The shear bond strength was not significantly different between axial planes (p > 0.05), but was significantly higher at 4 degrees than at 20 degrees (p = 0.009). A significant positive correlation was found between shear bond strength and tubule area (R = 0.43, p = 0.003) or tubule circumference (R = 0.42, p = 0.003), confirming the importance of resin penetration into the tubules. No correlation was found between shear bond strength and tubule density (R = 0.22, p > 0.05) or residual dentin thickness (R = -0.22, p > 0.05). More round and more elliptic tubule orifices characterized dentin prepared at 4 and 20 degrees, respectively. CONCLUSION: Regional variations in tubule cross-section appearance can modify the bond strength of adhesive resin luting cements.     

Effect of polymerization mode of adhesive and cement on shear bond strength to dentin

PURPOSE: To investigate the shear bond strength to dentin when two resin adhesive systems in light-cure, dual-cure, and auto-cure modes were used with three resin cements. This was done to determine the degree of compatibility that exists when resin products with different polymerization mechanisms are used together. METHODS: Three hundred non-carious human molars were divided into 30 test groups in which Prime & Bond NT and ScotchBond Multi-Purpose were used as adhesives with Calibra, Nexxus and Variolink cements to attach Rexillium III posts to flattened dentin surfaces. Debonding was achieved with an Instron testing machine and mean shear bond strengths were determined for each test group. The data were subjected to three-way ANOVA and post-hoc LSD testing to determine whether significant differences existed between the test groups. RESULTS: Bond strengths achieved were affected by the adhesive, the cement, and the cement curing mode. In general, the auto-cure application of the three cements demonstrated reduced shear bond strengths, both with respect to the different adhesives and their curing modes as well as compared to the dual-cure technique of the same cement. Additionally, Prime & Bond NT demonstrated considerably more variability than ScotchBond Multi-Purpose when used with both dual-cure and auto-cure varieties of the three cements. The bond strengths of resin cements depend on the curing mode of the cement and the adhesive. Unlike with direct light-cured resin composites, combining adhesive systems and dual-cured resin cements from different manufacturers may be contraindicated.     

Tensile bond strength of two ceramic and three resin composite inlay materials placed using a resin luting agent.

The tensile bond strength of inlay materials to dentin was evaluated. Five materials, two direct resin composite inlay products, one hybrid resin composite, a preformed ceramic block, and a conventional porcelain material were bonded to bovine dentin and bonded together using a dual-polymerizing resin luting agent. Specimens were tested with and without thermocycling. Some bar-to-bar bonding groups fractured through the bar. Significantly higher (P < .05) bar-to-bar bonds were recorded than the bar-dentin bonds, irrespective of the inlay materials. VitaDur N showed the lowest bar-to-bar failure values (7.6 MPa) compared to the four other inlay materials (14.4 MPa to 22.2 MPa), but had the highest dentin bond strength (4.5 MPa). Unexpectedly, thermal loading increased the bond strength to bovine dentin, although this was only statistically significant for VitaDur N. The dentin bond strength of Charisma (1.4 MPa) was inferior (P < .02) to all other materials (2.6 MPa to 4.5 MPa) when thermocycled before testing.