Total-etch Mode Research Articles

BOND STRENGTH AND MICROMORPHOLOGICAL FEATURES OF DENTIN SUBSTRATES TREATED WITH DIFFERENT ETCHING MODES USING UNIVERSAL ADHESIVE SYSTEM

This in-vitro study assessed bond strength and micromorphological features of dentin substrates treated with different etching modes using universal adhesive system. A total of 28 freshly extracted human molars with coronal dentin caries were used for this study. A total of 80 composite microcylinders with prepared dentin surface containing both sound dentin and carious affected dentin were divided into two main groups (40 each) according to the bonding mode used: Self-etch mode in one step single dose, and total-etch mode in two steps. Each group was then subdivided into two subgroups (20 specimens each) according to the type of dentin substrate used: Sound dentin and caries affected dentin. For the Scanning Electron Microscope (SEM) examinations, the teeth were divided into two main groups (8 each) according to the bonding mode used: Self-etch mode in one step single dose, and total-etch mode in two steps. Each group was then subdivided into two subgroups (4 specimens each) according to the type of dentin substrate used: sound dentin and caries affected dentin. The interfacial zone was examined using SEM at magnification 5000 X. Data was then recorded, tabulated and statistically analyzed. For sound dentin using total-etch mode (24.02 ± 1.03 MPa) showed statistically significantly lower µSBS than that using self-etch mode (28.04 ± 1.30 MPa) at p<0.05. For caries affected dentin using total-etch mode (18.46 ± 0.86 MPa) showed statistically significantly higher mean µSBS than that using self-etch mode (16.48 ± 0.84 MPa) at p<0.05. Independent of the etch mode used for bonding, sound dentin showed statistically significantly higher mean µSBS than that of caries affected dentin at p<0.05. These results were confirmed by the examination of the SEM images which revealed increase in number and length of resin tags for the groups showing high µSBS. In conclusion, using self-etch universal adhesives on sound dentin is considered to be material dependent. And using total-etch mode of universal adhesive on caries affected dentin can enhance bond strength. Moreover, the type of substrate and etching strategies may affect the bonding performance and durability of restorations in dentistry.

Microshear bond strength of universal adhesives to dentin used in total-etch and self-etch modes

Purpose To determine the dentin bonding ability of three new universal adhesive systems under different etching modes using microshear bond strength (μSBS). Materials and methods Futurabond U, Single Bond Universal, and Tetric N-Bond Universal were used in this study. Sixty noncarious human molars were assigned to three groups based on the type of the universal adhesives. Two etching modes (total-etch and self-etch) were employed for each adhesive group. The adhesives were applied on dentin surfaces according to the manufacturer's instructions then composite resin (Z350 XT, nanocomposite) was condensed through a polyethylene tube with a 1 mm internal diameter and 2 mm height attached firmly to dentin surfaces and light cured. All samples were thermocycled for 500 cycles from 5 to 55°C. The μSBS was measured by using universal testing machine at cross-head speed of 0.5 mm/min. The bonded surfaces were examined under a stereomicroscope at magnification ×50 to determine the mode of failure. Dentin slices were prepared for each group to evaluate the resin–dentin interface a resin composite with each adhesive were placed 2 mm thick to form composite core. The segments were sectioned longitudinally and prepared to be examined under scanning electron microscope. Results Among the universal adhesives, Futurabond U and Tetric N-Bond Universal in total-etch mode showed significantly higher μSBS values than in self-etch mode. Single Bond Universal did not show any significant difference in μSBS between the total-etch mode and self-etch mode. Conclusion Performance of universal adhesives was shown to be material-dependent. The results indicate that universal adhesives used on dentine performed better in total-etch mode than self-etch mode.

Clinical evaluation of three adhesive systems in class V carious lesions

Purpose The purpose of this study was to evaluate the clinical performance of three types of adhesive systems (Futurabond universal adhesive in a self-etch mode, Tetric N-bond self-etch adhesive, and Single bond universal adhesive in a total etch mode) in class V carious lesions over 1 year. Materials and methods A total of 20 patients with three carious cervical lesions were participated in this study after obtaining informed consent. A total of 60 restorations were placed. The distributions of adhesive materials and the teeth locations were randomized. Cavities were prepared limited to just removal of carious lesions with incisal and gingival margins in enamel and beveling of incisal cavosurface margin. All adhesives were applied following manufacturer's directions. All cavities were restored with Grandio SO composite resin following manufacturer's directions. Finishing and polishing was performed using finishing burs and polishing discs. Each restoration was clinically evaluated at baseline (24 h), 6 months and 1 year for retention, margin integrity, margin discoloration, secondary caries, and postoperative sensitivity using modified United state public health service (USPHS) criteria. Results The recall rate was 100% after 1 year. Also the retention rate for all restorations was 100% after 1 year. Using χ2-test, there was no statistically significant differences between the tested groups at all evaluation periods regarding marginal adaptation, marginal discoloration, and postoperative sensitivity (P > 0.05). None of restoration had secondary caries at any evaluation period. Conclusion Within the limitation of this short-term evaluation, there was no significant clinical difference between adhesives. Clinical significances All tested adhesive systems achieved excellent results after 1 year of clinical service.

Influence of application method on surface free-energy and bond strength of universal adhesive systems to enamel.

The aim of the present study was to determine the influence of different adhesive application methods and etching modes on enamel bond effectiveness of universal adhesives using shear bond strength (SBS) testing and surface free-energy (SFE) measurements. The adhesives Scotchbond Universal, All-Bond Universal, Adhese Universal, and G-Premio Bond were used. Prepared bovine enamel specimens were divided into four groups, based on type of adhesive, and subjected to the following surface treatments: (i) total-etch mode with active application; (ii) total-etch mode with inactive application; (iii) self-etch mode with active application; and (iv) self-etch mode with inactive application. Bonded specimens were subjected to SBS testing. The SFE of the enamel surfaces with adhesive was measured after rinsing with acetone and water. The SBS values in total-etch mode were significantly higher than those in self-etch mode. In total-etch mode, significantly lower SBS values were observed with active application compared with inactive application; in contrast, in self-etch mode there were no significant differences in SBS between active and inactive applications. A reduction in total SFE was observed for active application compared with inactive application. The interaction between etching mode and application method was statistically significant, and the application method significantly affected enamel bond strength in total-etch mode.

Exposed Dentin: Influence of Cleaning Procedures and Simulated Pulpal Pressure on Bond Strength of a Universal Adhesive System

PurposeTo compare various pre-treatments serving as cleaning procedures of dentin on the bond strength of resin composite promoted by a universal adhesive system applied either in the absence or presence of simulated pulpal pressure.Materials and MethodsPrior to application of the adhesive system (Scotchbond Universal) and resin composite (Filtek Z250), ground dentin surfaces were given one of five pre-treatments either without or with simulated pulpal pressure: 1) no pre-treatment, adhesive system in “self-etch” mode, 2) phosphoric acid etching, adhesive system in “total-etch” mode, 3) polishing with pumice on prophylaxis cup, 4) air abrasion with AIR-FLOW PLUS powder, 5) air abrasion with AIR-FLOW PERIO powder; n = 20/group of pre-treatment. After storage (37°C, 100% humidity, 24 h), micro shear bond strength was measured and data analyzed with parametric ANOVA including Bonferroni-Holm correction for multiple testing followed by Student’s t tests (significance level: α = 0.05).ResultsThe ANOVA found type of pre-treatment and simulated pulpal pressure to have no significant effect on dentin bond strength. The explorative post-hoc tests showed a negative effect of simulated pulpal pressure for phosphoric acid etching (adhesive system in “total-etch” mode; p = 0.020), but not for the other four pre-treatments (all p = 1.000).ConclusionAir abrasion with powders containing either erythritol and chlorhexidine (AIR-FLOW PLUS) or glycine (AIR-FLOW PERIO) yielded dentin bond strengths similar to no pre-treatment, phosphoric acid etching, or polishing with pumice. Simulated pulpal pressure reduced the bond strength only when the self-etch adhesive system was used in total-etch mode.

Comparative Evaluation of shear Bond Strength of universal Dental Adhesives -An in vitro study.

BackgroundPatient demand for tooth colored restorations and desire for minimally invasive restorations have made composites an indispensable part of the restorative process. An important factor affecting the intra-oral performance of composite restorations is bonding.Material and MethodsNinty six freshly extracted molar teeth were collected and occlusal 3mm is removed using a diamond disc to expose dentine. Following with samples were divided in to two main groups (self-etch & total etch). Each main group is again sub divided in to three groups each according to bonding agent used (Tetric N- Bond Universal, Single Bond Universal, Tetric N Bond Total etch in total etch group and Clear Fill SE in self etch group). Following which bonding protocol is followed according to manufacture instructions, a composite buildup of 2x3 mm is done on each specimen and then specimen were subjected to shear bond test under universal testing machine. All the readings were noted and subjected to statistical analysis using One way ANOVA and Tukey’s posthoc test.ResultsIt showed that there is no significant difference among the groups in both self-etch and total etch modes.ConclusionsIt can be concluded that application of an etching step prior to Universal Adhesives significantly improves their dentine penetration pattern, although this does not affect their mean SBS. The bond strength values of the TBU regardless of application mode were comparable to SBU making them reliable for working under different clinical conditions. Key words:Dentine bonding agents, self-etch mode, total etch mode, shear bond strength.

Effect of silane contamination on dentin bond strength

Statement of problemIntraoral repair of porcelain or other silica-based ceramics typically requires the use of silane in the repair protocol. Some porcelain intraoral repairs also involve bonding to exposed or involved tooth tissues including dentin. A study is needed to evaluate whether the cross-contamination of dentin with silane affects bond strength to this tissue. PurposeThe purpose of this in vitro study was to investigate the effect of silane cross-contamination on dentin bond strength. Material and methodsFlat surfaces of human dentin specimens were created, followed by wet polishing with 320-grit silicon carbide paper. The dentin specimens were divided into 4 groups: group SE (All-Bond Universal Adhesive used in self-etching mode); group SiSE (silane applied to dentin followed by All-Bond Universal Adhesive used in self-etching mode); group ER (All-Bond Universal Adhesive used in total-etch (etch-and-rinse) mode); and group ERSi (Etch and rinse and silane applied to dentin followed by All-Bond Universal Adhesive). The dentin specimens were treated with a universal adhesive (All-Bond Universal) and bonded with a composite resin, using an Ultradent jig mold. Shear bond strength (n=10) was measured after 24 hours of water storage at 37°C. After the shear bond strength test, the dentin sides of fractured specimens in each group were examined with a stereomicroscope at ×15 magnification to determine failure modes. Data were statistically analyzed by 2-way and a 1-way ANOVA followed by post hoc Tukey honest significant difference test (α=.05). Scanning electron microscopy examination was used to evaluate the dentin surface morphology before and after bonding. ResultsThe shear bond strength of composite resin to dentin was not affected adversely when the dentin was contaminated with silane prior to using All-Bond Universal in the self-etch or total- etch (phosphoric acid) mode. SE, 30.3 ±3.8 MPa; SiSE, 32.9 ±3.9 MPa; ER, 34.9 ±3.1 MPa; ERSi: 35.2 ±4.9 MPa (P>.05) ConclusionsUnder the conditions of this study, cross-contamination of dentin with silane before the use of All-Bond Universal in the self-etch or total-etch with phosphoric acid mode did not adversely affect composite resin bond strength to dentin.

Influence of Etching Mode on Enamel Bond Durability of Universal Adhesive Systems.

The purpose of this study was to determine the enamel bond durability of three universal adhesives in different etching modes through fatigue testing. The three universal adhesives used were Scotchbond Universal, Prime&Bond Elect universal dental adhesive, and All-Bond Universal light-cured dental adhesive. A single-step self-etch adhesive, Clearfil S3 Bond Plus was used as a control. The shear bond strength (SBS) and shear fatigue strength (SFS) to human enamel were evaluated in total-etch mode and self-etch mode. A stainless steel metal ring with an internal diameter of 2.4 mm was used to bond the resin composite to the flat-ground (4000-grit) tooth surfaces for determination of both SBS and SFS. For each enamel surface treatment, 15 specimens were prepared for SBS and 30 specimens for SFS. The staircase method for fatigue testing was then used to determine the SFS of the resin composite bonded to the enamel using 10-Hz frequencies for 50,000 cycles or until failure occurred. Scanning electron microscopy was used to observe representative debonded specimen surfaces and the resin-enamel interfaces. A two-way analysis of variance and the Tukey post hoc test were used for analysis of the SBS data, whereas a modified t-test with Bonferroni correction was used for the SFS data. All adhesives in total-etch mode showed significantly higher SBS and SFS values than those in self-etch mode. Although All-Bond Universal in self-etch mode showed a significantly lower SBS value than the other adhesives, there was no significant difference in SFS values among the adhesives in this mode. All adhesives showed higher SFS:SBS ratios in total-etch mode than in self-etch mode. With regard to the adhesive systems used in this study, universal adhesives showed higher enamel bond strengths in total-etch mode. Although the influence of different etching modes on the enamel-bonding performance of universal adhesives was found to be dependent on the adhesive material, total-etch mode effectively increased the enamel bond strength and durability, as measured by fatigue testing.

Influence of different etching modes on bond strength and fatigue strength to dentin using universal adhesive systems

ObjectivesThe purpose of this study was to determine the dentin bonding ability of three new universal adhesive systems under different etching modes using fatigue testing. MethodPrime & Bond elect [PE] (DENTSPLY Caulk), Scotchbond Universal [SU] (3M ESPE), and All Bond Universal [AU] (Bisco) were used in this study. A conventional single-step self-etch adhesive, Clearfil Bond SE ONE [CS] (Kuraray Noritake Dental) was also included as a control. Shear bond strengths (SBS) and shear fatigue strength (SFS) to human dentin were obtained in the total-etch mode and self-etch modes. For each test condition, 15 specimens were prepared for the SBS and 30 specimens for SFS. SEM was used to examine representative de-bonded specimens, treated dentin surfaces and the resin/dentin interface for each test condition. ResultsAmong the universal adhesives, PE in total-etch mode showed significantly higher SBS and SFS values than in self-etch mode. SU and AU did not show any significant difference in SBS and SFS between the total-etch mode and self-etch mode. However, the single-step self-etch adhesive CS showed significantly lower SBS and SFS values in the etch-and-rinse mode when compared to the self-etch mode. Examining the ratio of SFS/SBS, for PE and AU, the etch-and-rinse mode groups showed higher ratios than the self-etch mode groups. SignificanceThe influence of different etching modes on dentin bond quality of universal adhesives was dependent on the adhesive material. However, for the universal adhesives, using the total-etch mode did not have a negative impact on dentin bond quality.

BOND STRENGTH AND INTERFACIAL MORPHOLOGY OF A MULTIMODE ADHESIVE RESIN CEMENT TO ENAMEL AND DENTIN

Introduction: Resin cements are used for cementation of indirect restorations. A high-quality adhesion to tooth structure is primordial for the success of indirect cemented restorations. Objectives: Were to assess the shear bond strength of RelyX ultimate adhesive resin cement to both enamel and dentin when used in different application modes (self-etch and total-etch) and to study resin-tooth interfaces using SEM. Materials and methods: 40 enamel specimens and 40 dentin specimens were used in this study. Each substrate specimens were randomly divided into four groups of 10 specimens each according to resin cement applied: Enamel groups: Group A1: RelyX ultimate as total-etch; Group A2: RelyX ultimate as self-etch; Group A3: Variolink II; Group A4: Multilink automix. Dentin groups: Group B1: RelyX ultimate as total-etch; Group B2: RelyX ultimate as self-etch; Group B3: Variolink II; Group B4: Multilink automix. Resin cements were built over the surfaces following manufacturer's instructions in a plastic tube. All specimens were thermocycled (500 cycles, 5°/55°C, 15 sec dwell time) then shear bond strength was measured in MPa and data were analyzed using F-test (ANOVA) and Post Hoc test. Three specimens from each group were further sectioned, gold sputtered and evaluated under SEM. Results: All enamel groups showed a statistically significant difference for shear bond strength with P <0.001. Group A1 revealed the highest mean value of 35.60 MPa. While for dentin, there was no statistically significant differences among groups with P=0.053. Interfacial morphology of RelyX ultimate in total-etch mode showed better interface morphology and improved tag length compared to respective self-etch counterpart. Conclusions: An etching step prior to multi-mode adhesive resin cement increased its bond strength values and improved its penetration pattern to both enamel and dentin, also length of resin tags formed by total-etch adhesives seems not to play an important role in determining bond strength. Keywords: Resin cements, Adhesives, Multi-mode, dental substrates, bonding, interface.

Does 2% chlorhexidine digluconate cavity disinfectant or sodium fluoride/hydroxyethyl methacrylate affect adhesion of universal adhesive to dentin?

The objectives of this study were to investigate the adhesion of a universal adhesive used either in total-etch (TE) or self-etch (SE) mode with and without 2% chlorhexidine digluconate cavity disinfectant (CHX) or sodium fluoride/hydroxyethyl methacrylate (NaF/HEMA) to dentin. Dentin surfaces of extracted human non-carious third molar teeth (N = 18) were exposed and randomly assigned to two groups. Half of the teeth were conditioned with TE and the others with SE adhesive mode. The teeth were then randomly divided into two groups where half were cleaned with 2% CHX (Cavity Cleanser, Bisco, CC) and the other half with NaF/HEMA (Aqua Prep F, Bisco, APF). Control groups in TE (C1) and SE (C2) adhesive system did not receive any cavity disinfectant. Dentin surfaces were conditioned with universal adhesive (Single Bond Universal, SBU) and resin composite blocks (3 M Z550) were bonded incrementally on the conditioned dentin using a mold. The teeth were stored in water for 48 h, and from each tooth, beam-shaped specimens (1 mm2) were prepared (n = 14, per group). Microtensile bond strength (MBS) was measured using a universal testing machine (1 mm/min). Data (MPa) were analyzed using one-way ANOVA and Tukey’s test (α = 0.05). Two-parameter Weibull distribution values including the Weibull modulus, scale (m), and shape (0) values were calculated. Mean MTBS results (MPa) showed significant difference between the experimental groups (p = 0.001) and were in descending order as follows: C1-CC (32.8 ± 6.4)a < C1 (24.4 ± 5.2)b < C2 (21.1 ± 4.8)b < C1-APF (19.3 ± 4.4)b < C2-CC (14.1 ± 4.1)c < C2-APF (8.1 ± 2.1)d. C1 and C2 presented non-significant bond strength of the resin composite bonded with SBU (p > 0.05). CC application significantly increased the bond strength in TE mode, but significant reduction was observed when used in SE mode (p < 0.05). The use of APF did not significantly decrease the bond strength in TE mode, but significant reduction was observed when used in SE mode. Considering Weibull parameters, characteristics of adhesion seem to be less reliable for C2-CC (m = 3.86) and more reliable for C1-CC (m = 6.77). Failure types were predominantly adhesive between the dentin and the adhesive resin. Mixed failures were more common for both C1 and C2 and total etch-CC combination.

Two-year clinical trial of a universal adhesive in total-etch and self-etch mode in non-carious cervical lesions

ObjectivesTo compare the clinical performance of Scotchbond™ Universal Adhesive used in self- and total-etch modes and two-bottle Scotchbond™ Multi-purpose Adhesive in total-etch mode for Class 5 non-carious cervical lesions (NCCLs). Methods37 adults were recruited with 3 or 6 NCCLs (>1.5mm deep). Teeth were isolated, and a short cervical bevel was prepared. Teeth were restored randomly with Scotchbond Universal total-etch, Scotchbond Universal self-etch or Scotchbond Multi-purpose followed with a composite resin. Restorations were evaluated at baseline, 6, 12 and 24 months for marginal adaptation, marginal discoloration, secondary caries, and sensitivity to cold using modified USPHS Criteria. Patients and evaluators were blinded. Logistic and linear regression models using a generalized estimating equation were applied to evaluate the effects of time and adhesive material on clinical assessment outcomes over the 24 month follow-up period. Kaplan–Meier method was used to compare the retention between adhesive materials. ResultsClinical performance of all adhesive materials deteriorated over time for marginal adaptation, and discoloration (p<0.0001). Both Scotchbond Universal self-etch and Scotchbond Multi-purpose materials were more than three times as likely to contribute to less satisfying performance in marginal discoloration over time than Scotchbond Universal total-etch. The retention rates up to 24 months were 87.6%, 94.9% and 100% for Scotchbond Multi-purpose and Scotchbond Universal self-etch and total-etch, respectively. ConclusionsScotchbond Universal in self- and total- etch modes performed similar to or better than Scotchbond Multipurpose, respectively. Clinical significance24 month evaluation of a universal adhesive indicates acceptable clinical performance, particularly in a total-etch mode.

The Effect of Different Dental Adhesive Systems on Hybrid Layer Qualities

The study aimed to evaluate the quality of the hybrid layer form by three different adhesive systems. Class V cavities were prepared on the buccal surface of fourty extracted human premolars. The prepared teeth were randomly assigned into four groups according to the adhesive system and application mode. The systems were: Optibond S (OS, total-etch); Optibond Versa (OV, two-bottles, self-etch); Single Bond Universal (SBU, one-bottle, self-etch) and Single Bond Universal with etchant (SBU + etchant). All cavities were restored with composite (Filtek Z350XT). The samples were sectioned, polished and pretreated to remove minerals, protein and water prior to SEM evaluation. From the images, thickness of the hybrid layers was measured. Present of resin tags and adaptation failure were also recorded. The data obtained were analyzed using ANOVA, Dunnett’s T3, Kruskal-Wallis and Mann-Whitney tests. OS group showed the highest average hybrid layer thickness (4.34 μm), followed by SBU + etchant (3.06 μm), OV (1.91 μm) and SBU (0.95 μm). Both adhesive and cohesive failures were observed in SBU group. Present of prominent resin tags were seen in both OS and OV groups. In conclusion, all the investigated adhesive systems were able to perform distinguishable actions as shown in micro-morphological alteration and hybrid layer thickness. Two-bottles, self-etch adhesive (OV) was proven to produce negligible adaptation failure compared to other adhesive systems in the present study. Combined all-in-one adhesive (SBU) was found to render a superior bonding performance in total-etch mode comparing to self-etch mode.

The physical characteristics of resin composite–calcium silicate interface as part of a layered/laminate adhesive restoration

ObjectivesTo compare in-vitro micro-shear bond strengths (μSBS) of resin composite to calcium silicate cement (Biodentine™) vs. glass ionomer cement vs. resin modified glass ionomer cement (RM-GIC) using an adhesive in self-etch (SE)/total etch (TE) mode after aging three substrates and bond and characterizing their failure modes. MethodsResin composite was SE/TE bonded to 920 standardized disks of Biodentine™, GIC & RM-GIC. Dividing samples into two groups, the first underwent early (t=0min, 5min, 20min, 24h) or delayed (t=2wk, 1 month, 3 months, 6 months) substrate aging before bonding and μSBS (t=24h) testing. In the second, adhesive was applied after either early (t=5min) or delayed (t=2wk) substrate aging and then tested after bond aging (t=2wk, 1 month, 3 months, 6 months). The failure modes were identified using stereomicroscope. SEM images of selected samples were analyzed. ResultsNo significant differences were observed between (SE)/(TE) bonding modes (P=0.42). With substrate aging, a significant reduction in μSBS occurred between early and delayed time intervals for Biodentine™ (P=0.001), but none for the GIC/RM-GIC (P=0.465, P=0.512 respectively). With bond aging, there was no significant difference between time intervals for all groups, except at 6 months for the GIC (P<0.05). Modes of failure were primarily cohesive within all the substrates (68.82%) followed by adhesive failure at the resin–substrate interface (21.71%). SignificanceBiodentine™ is a weak restorative material in its early setting phase. Placing the overlying resin composite as part of the laminate/layered definitive restoration is best delayed for >2wk to allow sufficient intrinsic maturation to withstand contraction forces from the resin composite. A total-etch or self-etch adhesive may be used.