Effect of Sodium Hypochlorite in Ground Fluorotic Enamel: Shear Bond Strength and Surface Analysis

Evaluate the effect on the shear bond strength (SBS) of 5% NaOCl applied after acid etching on ground anterior teeth with fluorosis and analyze the surface with scanning electron microscopy (SEM), also compare fluorotic and healthy ground enamel by atomic force microscopy (AFM) and Vickers microhardness (VM). For the SBS test 30 anterior teeth with moderate and severe fluorosis according Dean index were selected by an examiner previously calibrated with an expert in fluorosis by using the intraclass correlation coefficient (ICC). With the help of a calibrated high speed diamond bur for veneer preparation and a parallel chamfer high speed diamond bur the vestibular face was prepared with a uniform reduction of .3 mm under water cooling. In one half of the vestibular face of the teeth the conventional adhesive procedure was carried out while in the other half was added an additional step with 5% NaOCl applied for 1 minute and washing after acid etchant. A resin post was adhered in each half and load was applied until fracture. The failure mode was evaluated and a SEM analysis was made. Posteriorly 10 samples of fluorotic and healthy ground enamel were used to measure the nanostructural characteristics by AFM (roughness average and absolute depth profile) and the VM in three operative steps (after ground, after etchant and after deproteinization). The Shapiro-Wilks and Brown-Forsythe methods were used to test the distribution of variables. The Paired Student's t-test was used to compare the differences between mean bond strength (MPa) in the two groups for SBS test. Chi-square analyzes were performed to compare the failure modes between groups. One-way ANOVA analysis and Tukey-Kramer post hoc test were used to compare groups for roughness average, absolute depth profile and Vickers microhardness. A greater SBS (32.17±4.20 MPa) and a surface more homogeneous and less contaminated were observed in the deproteinization subgruoup compared to the conventional subgroup (27.74±4.88 MPa). AFM parameters were greater in fluorosis subgroup than in healthy enamel subgroup. VM was lower in the fluorotic enamel in each operative step in comparation with healthy enamel. The use of 5% NaOCl as a deproteinizing agent after acid etchant in ground fluorotic enamel results in better adhesion, which may imply greater success in adhesive treatments. The ground surface of fluorotic enamel shows higher values of roughness and depth and lower values of VM which proves that there is a more irregular and less hard surface.

Enamel Etching for Universal Adhesives: Examination of Enamel Etching Protocols for Optimization of Bonding Effectiveness

SUMMARY Objective: The purpose of this study was to evaluate whether different enamel etching methods with reduced etching times would improve the bonding effectiveness of universal adhesives. Methods and Materials: Three enamel etching methods, phosphoric acid ester monomer (PPM) etching, phosphoric acid (PPA) etching, and polyalkenoic acid (PLA) etching, and three universal adhesives, G-Premio Bond (GP), Prime&Bond elect (PE), and Scotchbond Universal Adhesive (SU), were evaluated. Initial bond strengths and fatigue strengths of universal adhesives to ground enamel and ground enamel etched for less than one, five, 10, and 15 seconds using different etching methods were determined. The bonded fatigue specimens were loaded using a sine wave at a frequency of 20 Hz for 50,000 cycles or until failure occurred with a staircase method. Atomic force micrograph (AFM) observations along with measurements of surface Ra roughness and modified surface area of enamel with different etching protocols were also conducted. Results: The bond fatigue durability of universal adhesives to enamel with PPA etching from less than one to 15 seconds and PLA etching for 15 seconds was significantly higher than that to ground enamel. The bond fatigue durability to enamel with PPM etching was not increased compared with ground enamel. The surface Ra roughness and surface area obtained with AFM of enamel increased after PPA and PLA etching, and those values were significantly higher than those of ground enamel. Furthermore, surface Ra roughness and surface area with PPA etching were significantly higher than those with PLA etching. However, surface Ra roughness and surface area of enamel with PPM etching were similar to those of ground enamel regardless of etching time. Conclusion: PPA etching for less than one to 15 seconds and PLA etching for 15 seconds improve universal adhesive bonding, surface Ra roughness, and surface area of enamel. However, PPM etching is not effective, regardless of etching time, in improving bonds strengths, increasing surface roughness, and increasing surface area.

Comparing Shear Bond Strength of Two Step vs One Step B onding Agents on Ground Enamel and Dentin: An in vitro Study

ABSTRACT Aim To compare the shear bond strength of Tetric N Bond (Ivoclar Vivadent) and Single Bond Universal Adhesive (3M ESPE, MN, USA) on ground enamel and dentin. Materials and methods A total of 30 extracted human maxillary and mandibular molars and premolars were used for this study and divided into two groups which were treated with Tetric N Bond (Ivoclar Vivaden) t- and Single Bond Universal Adhesive (3M ESPE, MN, USA). The shear bond strength was tested on Universal testing machine (Instron). Results There was statistically significant difference in the shear bond strength among the two groups. Conclusion Based on the results (Tetric N Bond, Ivoclar Vivadent) had higher bond strength than Single Bond Universal Adhesive (3M ESPE, MN, USA) on ground enamel and dentin. How to cite this article Shah DD, Chandak M, Manwar N, Mani S, Mani A, Saini R, Malde R. Comparing Shear Bond Strength of Two Step vs One Step Bonding Agents on Ground Enamel and Dentin: An in vitro Study. Int J Experiment Dent Sci 2014;3(1):1-3.

Effect of EDTA and Phosphoric Acid Pretreatment on the Bonding Effectiveness of Self-Etch Adhesives to Ground Enamel

Objectives: This in vitro study determined the effect of enamel pretreatment with phosphoric acid and ethylenediaminetetraacetic acid (EDTA) on the bond strength of strong, intermediary strong, and mild self-etching adhesive systems.Methods: Ninety sound human premolars were used. Resin composite cylinders were bonded to flat ground enamel surfaces using three self-etching adhesive systems: strong Adper Prompt L-Pop (pH=0.9–1.0), intermediary strong AdheSE (pH=1.6–1.7), and mild Frog (pH=2). Adhesive systems were applied either according to manufacturer instructions (control) or after pretreatment with either phosphoric acid or EDTA (n=10). After 24 hours, shear bond strength was tested using a universal testing machine at a cross-head speed of 0.5 mm/minute. Ultra-morphological characterization of the surface topography and resin/enamel interfaces as well as representative fractured enamel specimens were examined using scanning electron microscopy (SEM).Results: Neither surface pretreatment statistically increased the mean shear bond strength values of either the strong or the intermediary strong self-etching adhesive systems. However, phosphoric acid pretreatment significantly increased the mean shear bond strength values of the mild self-etching adhesive system. SEM examination of enamel surface topography showed that phosphoric acid pretreatment deepened the same etching pattern of the strong and intermediary strong adhesive systems but converted the irregular etching pattern of the mild self-etching adhesive system to a regular etching pattern. SEM examination of the resin/enamel interface revealed that deepening of the etching pattern was consistent with increase in the length of resin tags. EDTA pretreatment had a negligible effect on ultra-morphological features.Conclusions: Use of phosphoric acid pretreatment can be beneficial with mild self-etching adhesive systems for bonding to enamel. (Eur J Dent 2010;4:418-428)

Effect of Configuration Factor on Shear Bond Strengths of Self-etch Adhesive Systems to Ground Enamel and Dentin

Clinical Relevance Despite recent improvements in self-etch bonding systems, a two-step etch and rinse system gave consistently higher shear bond strengths to both ground enamel and dentin and would be the best system to use clinically.

Effects of Surface Texture and Etching Time on Roughness and Bond Strength to Ground Enamel

Aim The aim of this study was to assess the influence of surface texture and etching technique on surface roughness (Ra) and bond strength (BS) to enamel and to determine if a correlation exists between them. Methods and Materials Fifty enamel blocks were either roughened with 600-grit SiC paper or polished with diamond pastes. After establishing ten test groups (n=5), the initial Ra measurements, rough (R) and smooth (S) enamel surfaces were etched according to the following protocols: Group 1(R)/Group 2(S)- 35% phosphoric acid gel (H3PO4) for 15 seconds; Group 3(R)/Group 4(S)- 35% H3PO4 for 60 seconds; Group 5(R)/Group 6(S)- Clearfil SE Bond primer for 20 seconds; Group 7(R)/Group 8(S)- self-etching primer (SEP) for 60 seconds; Group 9(R)/ Group 10(S)- 35% H3PO4 for 15 seconds + SEP for 20 seconds. After treatments, a new Ra measurement was performed and enamel surfaces were bonded with either Single Bond (Group 1 to Group 4) or Clearfil SE Bond (Group 5 to Group 10). Afterwards, specimens were prepared for the microtensile test. Ra values were analyzed using repeated-measures analysis of variance (ANOVA) and the BS values were analyzed using a two-way ANOVA and Tukey test (5%). Correlation between BS and Ra values was assessed using the Pearson's test. Results The application of SEP produced the lowest Ra values. No significant difference was detected between the BS values of polished and rough surfaces. No correlation was observed between Ra and BS values. Even though etching enamel with the SEP resulted in a surface with less roughness, similar BS values were observed for both self-etching and etch-and-rinse techniques. Conclusion Within the limits of this study increasing the etching time or combining both etching techniques failed to improve the BS using SEP or etch-and-rinse systems. Clinical Significance Based on the findings of this study, there is no clinical justification for increasing the etching time or for combining the use of a SEP following the use of a 35% H3PO4 etchant to achieve a greater BS to ground enamel. Citation Reis AF, Aguiar FHB, Pereira PNR, Giannini M. Effects of Surface Texture and Etching Time on Roughness and Bond Strength to Ground Enamel. J Contemp Dent Pract 2009 July; (10)4:017-025.

Two-year Water Degradation of Self-etching Adhesives Bonded to Bur Ground Enamel

Clinical Relevance All the adhesives tested showed no difference in bond strength after 24-hours of water storage. After two years of water storage, the bonds produced by some self-etch adhesives were significantly reduced.

The Influence of Temperature of Three Adhesive Systems on Bonding to Ground Enamel

Clinical Relevance The temperature of adhesive systems must be considered an important factor for the good clinical performance of bonding procedures.