Higher Shear Bond Strength Values Research Articles

Comparative Assessment of the Shear Bond Strength of Ceramic Brackets Bonded to the Enamel Surface with a Self-adhesive System

Objectives: This study aimed to evaluate the shear bond strength of ceramic brackets bonded to the enamel surface using Vertise Flow, with or without the application of phosphoric acid. Materials and Methods: Forty-five extracted human premolar teeth were randomly assigned to three groups (N=15) based on the adhesive used for bonding: 1) Transbond XT, etch, and bond; 2) Vertise Flow; 3) Etch and Vertise Flow. After a 500-round thermocycling procedure, the shear bond strength was measured using a universal testing machine. The samples were then evaluated under a stereomicroscope to determine failure modes, and the Adhesive Remnant Index (ARI) was measured for each group. The data were analyzed with one-way ANOVA and post-hoc Tamhane at a significance level of P<0.05. Results: The highest shear bond strength values were observed in the Transbond XT (13.5±5.38MPa), acid etch and Vertise Flow (11.2±2.89MPa), and Vertise Flow (6.2±3.16MPa) groups, respectively, in descending order. The Vertise Flow group exhibited a significantly lower shear bond strength value compared to the other two groups, with no significant difference between the latter two. Conclusion: While all three study groups demonstrated clinically acceptable shear bond strength values, Vertise Flow showed lower values compared to the other two adhesives. The Vertise Flow composite resin system, whether used alone or with acid etching, remains a suitable choice for bonding ceramic brackets, offering the advantage of a simplified bonding procedure.

The Effect of Different Chemical Surface Treatments on the Bond Strength of Resin-Matrix Ceramic Repaired with Resin Composite.

This study investigates the effect of different chemical surface treatment protocols with different functional monomers of universal adhesives on the shear bond strength between resin-matrix ceramic and resin composite. Eighty resin-matrix ceramics (Shofu block HC) were built and designed into eight groups of ten specimens and surface treated with HC primer (HC) and/or three universal adhesives (single bond universal [SBU], Scotchbond universal plus [SBP], and Tetric N-bond universal [TNU]) assigning follows; group 1, nonsurface treated; group 2, HC; group 3, SBU; group 4, HC + SBU; group 5, SBP; group 6, HC + SBP; group 7, TNU; group 8, HC + TNU. A template was put on the specimen center, and then pushed packable resin composite. Mechanical testing machinery was used to examine the samples' shear bond strength (SBS) values. To examine failure patterns, the debonded specimen surfaces were examined by a stereomicroscope. The one-way analysis of variance method was used to evaluate the data, and the Tukey's test was used to determine the significant level (p < 0.05). The highest SBS was obtained in group 6 (39.25 ± 1.65 MPa). Group 1 (4.15 ± 0.54 MPa) had the lowest SBS. Group 6 exhibited the highest percentage of cohesive failure patterns (70%). High SBS values were frequently correlated with the surface treatment groups and the cohesive failure patterns. The application of HC primer prior to the universal adhesive is an alternative protocol for enhancing the repair bond strength between resin-matrix ceramic and resin composite interfaces. Moreover, the application of HC primer prior to the SBP is the best strategy for resin-matrix ceramic and resin composite repairs.

Evaluation of the Effect of Different Bonding Systems and Restorative Materials on Shear Bond Strength in the Repair of High-Viscosity Glass Ionomer Cement

Aim: High viscosity glass ionomer cements have been produced to increase the mechanical properties of glass ionomer cements. The aim of this study is to determine the appropriate adhesive system and restorative material that can be used in fracture repair of high viscosity glass ionomer cements. Material and Methods: A total of 140 standard size acrylic blocks were used in the study. 14 groups were formed from randomly selected acrylic blocks, with 10 samples in each group. High viscosity glass iomomer cement was placed in the first 13 groups, and resin-modified glass ionomer cement was placed in the last group. After the thermal cycle aging process was applied to all samples, repair restorations were performed with 4 different adhesive systems, 2 different composite resins and 2 different restorative types of glass ionomer cement. After the repair restorations, thermal cycle aging was applied again and the shear bond strengths were evaluated. One-way analysis of variance and Duncan multiple comparison test were used for statistical analysis. Results: The highest shear bond strength values were obtained by the total etch adhesive system (p&lt;0.001). The lowest shear bond strength values were obtained when high-viscosity glass-iomomer cement without adhesive system was restored with high-viscosity glass iomomer cement (p&lt;0.001). Conclusion: For higher shear bond strength values in the repair of high-viscosity glass ionomer cements should use to total etch adhesive systems and composite resin.

Effect of different surface roughening treatment on polyether ether ketone and acrylic resin bonding: A pilot study.

As polyether ether ketone (PEEK) is a relatively new material in dentistry, its bonding properties with regard to dental acrylic base materials are not fully known. To ensure the long-term success of removable dentures with a PEEK framework, the base materials must be well bonded to each other. The study aimed to investigate the effects of different kinds of surface roughening treatment on PEEK and acrylic resin bonding. Eighty PEEK specimens (N = 80) were randomly divided into 5 groups (n = 16 per group) and subjected to various surface roughening treatment (control, grinding, sandblasting, tribochemical silica coating (CoJet), and sulfuric acid etching). Heat-polymerized acrylic resin was applied to the treated surfaces of the PEEK specimens. The shear bond strength (SBS) test, environmental scanning electron microscopy (ESEM) analysis and three-dimensional (3D) surface topography analysis were performed. The statistical analysis of the data was conducted using the analysis of variance (ANOVA) and Tukey's multiple comparison test. The one-way ANOVA showed significant differences in the SBS values between the groups (p = 0.001). Sandblasting, tribochemical silica coating and sulfuric acid etching resulted in high SBS values (p = 0.001). The highest SBS values were observed in the sulfuric acid etching group (8.83 ±3.63 MPa), while the lowest SBS values were observed in the control group (3.33 ±2.50 MPa). The additional roughening treatment applied to the PEEK surface increases the bond strength with heat-polymerized acrylic resin.

Comparison of the shear bond strengths of two different polyetheretherketone (PEEK) framework materials and CAD–CAM veneer materials

BackgroundThis study evaluated the shear bond strength (SBS) of two different polyetheretherketone (PEEK) and CAD-CAM materials after aging.MethodsA total of 42 frameworks were designed and milled from 2 different PEEK discs (Copra Peek, P and BioHPP, B). P and B frameworks were divided into 3 subgroups (n = 7). 14 slices were prepared each from feldspathic ceramic (Vitablocs Mark II, VM), hybrid nanoceramic (Cerasmart, CS), and polymer-infiltrated ceramic (Vita Enamic, VE) blocks. After surface preparations, the slices were cemented to P and B surfaces. The samples were subjected to thermal aging (5000 cycles). SBS of all the samples was measured. Fractured surfaces were examined by SEM/EDX analysis. The Shapiro–Wilk, Two-way Robust ANOVA and Bonferroni correction tests were used to analyze the data (a = .05).ResultsFrameworks, ceramics, and frameworks x ceramics had significant differences (p < 0.05). The highest SBS value was seen in B-VM (p < 0.05). VM offered the highest SBS with both P and B. The differences between P-VM, P-CS, P-VE and B-CS and B-VE were insignificant (p > 0.05). According to EDX analysis, ytterbium and fluorine was seen in B content, unlike P. While VM and CS contained fluorine, barium, and aluminum; sodium and aluminum were observed in the VE structure.ConclusionBonding of P and B with VM offers higher SBS. VM, CS and VE did not make any difference in SBS for P, however VM showed a significant difference for B.

The Effect of Surface Treatments on Shear Bond Strength between Orthodontic Metal Bracket and Porcelain Face

The Effect of Surface Treatments on Shear Bond Strength between Orthodontic Metal Bracket and Porcelain Face

Shear bond strength of calcium silicate-based cements to glass ionomers

BackgroundA shear bond strength between the biomaterial and restorative material is crucial for minimizing bacterial microleakage and ensuring a favorable long-term prognosis for vital pulp therapy. This study aimed to conduct a comparative evaluation of the shear bond strength between calcium silicate-based biomaterials utilized in vital pulp treatment and various glass ionomer cement materials, both with and without the application of adhesive agents.MethodsA total of 270 acrylic blocks, each featuring cavities measuring 4 mm in diameter and 2 mm in depth, were prepared. Calcium silicate-containing biomaterials (ProRoot MTA, Medcem Pure Portland Cement, and Medcem MTA), following manufacturers’ instructions, were placed within the voids in the acrylic blocks and allowed to set for the recommended durations. The biomaterial samples were randomly categorized into three groups based on the restorative material to be applied: conventional glass ionomer cement, resin-modified glass ionomer cement, and bioactive restorative material. Using cylindrical molds with a diameter of 3.2 mm and a height of 3 mm, restorative materials were applied to the biomaterials in two different methods, contingent on whether adhesive was administered. After all samples were incubated in an oven at 37 °C for 24 h, shear bond strength values were measured utilizing a universal testing device. The obtained data were statistically evaluated using ANOVA and post-hoc Tukey tests.ResultsThe highest shear bond strength value was noted in the Medcem MTA + ACTIVA bioactive restorative material group with adhesive application, while the lowest shear bond strength value was observed in the ProRoot MTA White + Equia Forte HT Fil group without adhesive application (P < 0.05).ConclusionActiva Bioactive Restorative may be considered a suitable restorative material in combination with calcium silicate-based biomaterials for vital pulp treatment. The application of adhesives to calcium silicate-based biomaterials can effectively address the technical limitations.

Comparison of shear bond strength and residual adhesive remnants on the enamel surface after debonding of three different orthodontic molar tubes : Ascanning electron microscope study.

The aim for this research was to evaluate and compare the impact, bond strength, and residual adhesive on the enamel surface after debonding of different orthodontic molar tubes. The tested materials were metal, composite, and newly introduced ceramic orthodontic molar tubes. In all, 66first molar teeth were randomly divided into three groups. Metal, glass-fiber composite and ceramic orthodontic molar tubes were bonded and shear bond strength (SBS) tests were performed. The adhesive remnant index (ARI) scores after debonding were recorded and the enamel surfaces were investigated using scanning electron microscopy (SEM) after the adhesives were cleaned. The mean SBS values of the metal and ceramic tube groups were significantly higher than that of the glass-fiber composite tube group. The highest SBS values were recorded for the ceramic tube group (11.09 ± 2.51 MPa). Failure typically occurred at the adhesive-enamel interface in the ceramic group, whereas the majority of the samples in the glass-fiber composite group showed failure at the adhesive-tube base interface according to ARI and SEM investigations. ARI1 and ARI2 scores were commonly observed for the metal tube group. All the molar tubes tested had generated clinically acceptable SBS values; however, the values for glass-fiber composite molar tubes were significantly lower than those for the ceramic and metal molar tubes. If the debonding procedure is performed carefully, the ceramic molar tubes may be an enamel-safe product for patients seeking fully esthetic orthodontic treatment.

Bond Strength of Reline Materials to 3D-Printed Provisional Crown Resins.

(1) Purpose: The aim of the present study was to compare the bond strength between two 3D-printed resins designed for long-term provisional crowns and three different reline materials. (2) Materials and Methods: Rectangular specimens were prepared from two 3D-printed resins (Envision Tech and NextDent C&B) and a conventional self-cure PMMA. Transparent tubes filled with three different reline materials including composite resin, Bis-acryl, and PMMA were bonded to the 3D-printed specimens (n = 11 per group, total of 6 study groups). Tubes filled with PMMA were bonded to the prepared PMMA specimens which served as the control group (n = 11, control group). The specimens were subjected to a shear bond strength (SBS) test, and mode of failure was recorded using light microscopy. Statistical analysis was performed using a one-way ANOVA and post hoc Tukey's tests (alpha = 0.05). (3) Results: The highest SBS value was achieved to both 3D-printed materials with the PMMA reline material. The bond to both 3D-printed materials was lower with Bis-acrylic or composite resin relines in comparison to that with PMMA (p-value < 0.05). No significant difference was found between the control PMMA group and either 3D-printed material when relined with PMMA (p-value > 0.05). (4) Conclusion: The tested 3D-printed resins achieved a clinically acceptable bond strength when relined with PMMA.

Analysis of the bond strength between conventional, putty or resin-modified calcium silicate cement and bulk fill composites.

The aim of this study was to evaluate the shear bond strength of three different calcium silicate-based cements (CBCs) with two different bulk-fill composite resins (CRs). Plexiglas moulds with a diameter of 4 mm and a thickness of 2 mm were prepared (n = 60). The Biodentine, NeoPutty and MTA Cem LC samples were randomly divided into two subgroups containing 10 samples each. Surfaces of samples were air dried and Single Bond universal adhesive was applied. Cylindrical plastic capsules of 4 mm height and 2 mm inner diameter belonging to Filtek Bulk-fill and EverX Posterior CRs were centred on coating material and polymerized for 20 s. After shear bond strength (SBS) testing, all samples were examined by scanning electron microscopy (SEM) to identify failure patterns. Three samples, one from each group, were prepared to evaluate chemical composition of CBCs and examined with an energy dispersive X-ray spectroscopy for surface elemental analysis. The values obtained from the tests were evaluated as statistically significant (P < 0.05). After SBS testing, the difference between all CBCs was statistically significant in both CRs. According to the findings in this study, it was concluded that MTA Cem LC had highest SBS values in both CRs. © 2023 Australian Dental Association.

Effect of Dentin and Zirconia Surface Treatments with Laser Irradiation Versus Sandblasting on the Bonding Ability of Zirconia.

Objective: This study aimed to investigate the effects of laser irradiation applied to zirconia and tooth surfaces on shear bond strength (SBS) compared with acid etching and sandblasting. Background: The effect of laser irradiation on the bond strength between zirconia and adhesives is a controversial issue for dentin surface treatments. In addition, the effects of different combinations of surface treatments to increase adhesion on both the zirconia and dentin surfaces remain unclear. Materials and methods: A total of 90 tooth samples were assigned into groups according to various pretreatments: control group was left untreated, acid etching, and Erbium, Chromium:Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) laser irradiation group (15 Hz, 2 W). In addition, the zirconia specimens were separated into three groups (n = 10) according to the different surface treatments performed: sandblasting (120 μm Al2O3), Er,Cr:YSGG laser (15 Hz, 2 W), and as untreated surface. The zirconia samples were cemented to the dentin surface using dual-cure resin cement and subjected to an SBS test at a speed of 0.5 mm/min under a universal testing machine until fractures occurred in the bonding surface. Results: The highest SBS values were observed in Group tooth acid (TA)-zirconia Er,Cr:YSGG laser (ZL), followed by Group tooth Er,Cr:YSGG laser (TL)-zirconia sandblasting (ZS) and Group TA-zirconia control (ZC). The lowest SBS values were found in Group TA-ZS. Significant intergroup difference was noted between Group TA-ZL, Group tooth control (TC)-ZC, Group TL-ZS, and Group TC-ZC. However, no significant difference was noted between Group TA-ZL, Group TL-ZS, and Group TA-ZC. Conclusions: Acid etching and laser treatments applied to the dentin and zirconia surfaces were found to be effective techniques for improving the zirconia-dentin bond, respectively. Clinical Trial Registration number: 33216249-604.01.02-E.24308.

Surface Modification Methods of Self-Cured Acrylic Resin Repaired with Resin Composite Using a Universal Adhesive

This research study’s purpose was to evaluate the mechanical and chemical surface treatment methods for self-cured acrylic resin repaired with a resin composite employing a universal adhesive agent. Eighty self-cured acrylic resins were built and designed into eight groups of ten specimens and surface conditioned using sandblasting (SB) and/or with methylmethacrylate monomer (MMA) and/or universal adhesive (UA) as follows: Group 1, non-surface modified; Group 2, SB; Group 3, UA; Group 4, SB + UA; Group 5, MMA; Group 6, SB + MMA; Group 7, MMA + UA; Group 8, SB + MMA + UA. A template was put on the specimen center, and the pushed resin composites. Mechanical testing machinery was used to examine the samples’ shear bond strength (SBS) values. To examine failure patterns, the debonded specimen surfaces were examined using a scanning electron microscope. The one-way ANOVA method was used to evaluate these data, and Tukey’s test was used to determine the significance level (p &lt; 0.05). The highest SBS was obtained in Group 8 (27.47 ± 2.15 MPa); however, it was statistically equivalent to Group 7 (25.85 ± 0.34 MPa). Group 1 (4.45 ± 0.46 MPa) had the lowest SBS, but it was not statistically significant compared to Group 2 (5.26 ± 0.92 MPa). High SBS values were frequently correlated with cohesive patterns. The application of MMA prior to UA is the best method for increasing the SBS between self-cured acrylic resin and resin composite interfaces. However, the use of SB is not significantly different from not using SB.

A comparison of bond strength and adhesive remnant index of 3D-printed and metal orthodontic brackets attached using different adhesives

Abstract Introduction The aim of this in vitro study was to evaluate the shear bond strength (SBS) and adhesive remnant index (ARI) scores of two different adhesive applications of aesthetic brackets produced from permanent crown material using 3D-printing technology. Methods Sixty maxillary premolar teeth extracted for orthodontic reasons were divided into two main groups according to the type of bracket (metal brackets n=30, 3D-printed brackets n=30) and further divided into two subgroups according to the type of adhesive (flowable composite, Tokuyama SuperLow; non-flowable composite; 3M Transbond XT). SBS and ARI score evaluations were conducted in the experimental and control subgroups (n=15). Statistical analysis was performed by a one-way analysis of variance, a post-hoc test, and Fisher’s exact test. Statistical significance was accepted as P &lt; 0.05. Results The bond strength of the specimens was significantly affected by the type of composite and bracket type (P &lt; 0.001). However, the SBS values were within or above the desired range for orthodontic treatment in all groups. The highest SBS value was obtained in the Metal Bracket-Transbond XT group (15.03 ± 6.66), while the lowest SBS value was observed in the 3D-Printed Bracket-Transbond XT group (7.91 ± 3.07). It was noted that of all materials evaluated, the most common non-enamel-damaging adhesive–cohesive fractures were in 3D-Printed Bracket Tokuyama SuperLow group (n=13). Conclusions It is recommended that 3D-printed orthodontic brackets have sufficient and acceptable SBS levels for clinical applications and bonding using non-flowable adhesives to produce high SBS values and using flowable adhesives generating high ARI scores.

What is the most effective technique and composite for bonding aligner attachments to primary enamel?

Objectives: This in vitro study evaluated the shear bond strength (SBS) of aligner attachments bonded to primary teeth with different techniques and composites. Material and Methods: Eighty attachments were prepared using five composites: An aligner composite (GC aligner connect [GAC]), two flowable restorative composites (G-aenial universal injectable and Estelite universal super low flow), and two one-step orthodontic composites integrated with primer (GC ortho connect flow and GC ortho connect). Aligner and restorative composites were applied with self- or total-etch (SE or TE) modes of universal adhesive (G-Premio Bond). Self-adhering composites integrated with primer were applied after acid etching. Excessive composites were removed with tungsten carbide burs after the polymerization of resin attachments. All primary teeth were exposed to thermocycling. Bond strength was determined with a universal testing machine. Remnant resin attachment was scored with the resin attachment remnant index. Kruskal–Wallis, Mann–Whitney, and Chi-square tests were used for statistical analyses. Results: The self-etching technique demonstrated lower SBS values compared to total-etching and self-adhering groups regardless of composite type. The highest SBS was found with aligner composite (GAC) and the total-etching technique. Self-adhering composites showed sufficiently high SBS values comparable with GAC and TE bonding techniques. The amount of remnant attachment was significantly higher in the total-etching and self-adhering groups compared to SE bonding with GAC (P &lt; 0.05). Conclusion: Self-adhering orthodontic composites can be preferred to simplify the bonding of aligner attachments to primary enamel after acid etching.

Effect of different interfacial surface treatments on the shear bond strength of veneering ceramic and zirconia core

BackgroundSeveral interfacial surface treatments of zirconia surfaces have been proposed to improve adhesion to ceramic veneering. However, information regarding the durability and effect of such treatments on the bond strength following such treatments is lacking.Aim of the studyThis study aimed to evaluate the shear bond strength between veneering ceramic and zirconia core after different interfacial surface treatments.Materials and methodsFifty-two discs (8 mm in diameter and 3 mm in height) were fabricated from zirconia blanks using a microtome cutting machine. Zirconia discs were divided into four groups (n = 13). Group I was subjected to air-borne abrasion using (Al2O3), group II was coated by bioglass, group III was coated with ZirLiner, and group IV was subjected to wash firing (sprinkle technique). A cylinder (4 mm in diameter and 3 mm in height) of veneering ceramic was fired on top of the zirconia core. Shear bond strength (SBS) between zirconia core and veneering ceramic was evaluated by using a universal testing machine. The data was collected and statistically analysed using One-Way ANOVA followed by multiple pairwise comparisons using Bonferroni adjusted significance level. The failure modes were assessed using a stereomicroscope for each group.ResultsThe highest mean bond strength was recorded in group III (17.98 ± 2.51 MPa), followed by group II (15.10 ± 4.53 MPa), then group I 14.65 ± 2.97 MPa. The lowest mean bond strength was recorded in group IV (13.28 ± 3.55 MPa).ConclusionsSurface treatments had an effect on the zirconia-veneer shear bond strength. Liner coating revealed the highest shear bond strength values, significantly higher in comparison to wash firing (sprinkle technique) .

Impact of a High-Power Light-Emitting Diode Unit With Reduced Curing Times on the Shear Bond Strength of Orthodontic Brackets and Their Adhesive Remnant Index Scores.

This study aims to evaluate the curing time minimally required for bonding stainless-steel (SS) brackets using a high-power light-emitting diode (LED) light curing unit (LCU) and examine the debonded enamel surface for adhesive remnant. Based on the LED LCU and curing time employed, 80 human maxillary first premolar teeth were equally segregated into four groups. Three groups were cured using a high-power LED unit (Guilin Woodpecker Medical Instrument Co., Ltd., Guilin, Guangxi, China) for one, two, and three seconds. The fourth group served as a control and was bonded with another intensive LED unit (Elipar™ S10 LED Curing Light; 3M, Saint Paul, Minnesota, United States) for 20 seconds. Transbond™ XT Light Cure Adhesive (3M, United States) adhesive was used for bonding the SS brackets. All the samples were exposed to shear bond strength (SBS) testing after a 24-hour immersion period in distilled water at 37°C. A stereomicroscope was used to examine and score the adhesive remnant on the debonded surface using a modified adhesive remnant index (ARI). Kruskal-Wallis-ANOVA and post-hoc Mann-Whitney U tests for multiple pairwise comparisons were performed to analyze the data. Time and intensity significantly affected the SBS (P<0.001). A higher SBS value (16.04 megapascals (MPa)) was obtained in the six-second group when compared to the three-second (11.58 MPa), one-second (10.69 MPa), and 20-second control (13 MPa) groups. The ARI was significantly affected by the curing method. Higher SBSs were recorded for the six-second group using the high-power LED. A greater ARI score is associated with a reduced curing duration and vice versa.

Comparative Evaluation of Shear Bond Strength of Glass Ionomer Cement, Composite and Compomer in Primary Teeth: An In Vitro Study

Background: Because the main dislodging pressures at the tooth restoration interface have a shearing effect, shear bond strength is crucial for the restorative material clinically. Therefore, greater shear bond strength suggests improved material to tooth bonding. Glass ionomer cement and composite is the most popularly used restorative material. Composite resins have better mechanical properties and esthetics than many other types of cement, but they need bonding agents as they are hydrophobic and hence fail to adhere to the teeth. Compomers are polyacid modified resin composites. Compomer and composite resin have similar physical properties, as they are thought to bond to dentin by micromechanical bonding. As resin composites are used in this, the polymerized acid monomer shows acidity when it comes in contact with the saliva and there is a reaction of fluoride-containing basic glass resulting in the cariostatic effect. Aim: The purpose of this study was to evaluate and compare the shear bond strength of Glass Ionomer Cement (Fuji IX GP), Composite Resin (Filtek Z-250) and Compomer, (Compoglass, Ivoclar). Material and Method: An in-vitro, experimental study was conducted on 30 freshly extracted over-retained deciduous molars. Samples were randomly divided into three groups depending on the material to be used. Flat dentinal surface on tooth was prepared over which restorative materials were placed. The prepared specimen was subjected to shear test and the value obtained was compared. Descriptive statistical analysis was performed to calculate the mean shear bond strength of each group. Result: It was observed from the study that the composite resin had the highest shear bond strength value (17.13 ± 1.54), followed by compomer (11.32 ± 1.05) whereas GIC showed the least shear bond strength (6.56 ± 0.87). Conclusion: It was concluded that composite restorative materials show higher shear bond strength than glass ionomer cement and compomer in primary molars, but shear bond strength of compomer was higher than that of glass ionomer cement.

Comparing the shear bond strength of veneering materials to the PAEKs after surface treatments

BackgroundThis study aimed to evaluate the impact of various surface treatments on the shear bond strength (SBS) of polyetheretherketone (PEEK) and polyetherketoneketone (PEKK) polymers to indirect laboratory composite (ILC) and lithium disilicate ceramic (LDC) veneering materials.MethodsPolymer specimens (7 × 7x2 mm) were sectioned from PEEK and PEKK discs (N = 294) and randomly allocated to 7 groups (n = 20); untreated (Cnt), plasma (Pls), 98% sulfuric acid (Sa), sandblasting with 110 µm Al2O3 (Sb), tribochemical silica coating with 110 µm silica modified Al2O3 (Tbc), Sb + Sa, Tbc + Sa. Scanning electron microscopy assessments were performed on one sample of each treatment group, and veneering materials were applied to the remaining specimens (n = 10). The specimens were subjected to the SBS test after being soaked in distilled water (24 h, 37 °C). Three-way ANOVA, independent sample t-test, and Tukey HSD test were performed for statistical analyses (α = .05).ResultsThe surface treatment, polymer, veneering material types, and their interactions were significant on SBS results according to the 3-way ANOVA (p < 0.001). The SBS values of ILC veneered groups were significantly higher than LDC groups, regardless of surface treatment and polymer type (p < 0.05). The highest SBS values were obtained for Sa-applied ILC veneered PEEK (21.55 ± 1.45 MPa) and PEKK (17.04 ± 1.99 MPa) polymer groups (p < 0.05).ConclusionThe effect of surface treatment and veneering materials may be significant on the SBS values of PAEKs. Therefore, the application parameters of surface treatments should be more specified for the applied veneering material and polymer type.

&lt;i&gt;In Vitro&lt;/i&gt; Evaluation of the Effects of Different Chemical Solvent Agents on Shear Bond Strength of Ceramic Orthodontic Brackets

In this study, the effects of different chemical solvents such as acetone, ethanol, dimethyl sulfoxide (DMSO), peppermint oil, and hot water on the shear bond strength (SBS) of mechanically and chemically bonded ceramic brackets were examined. Their use for facilitation of the debonding process in practice was evaluated regarding the purposes of this study. One hundred and thirty-two human premolar teeth extracted for orthodontic purposes were randomly divided into 11 groups. SBS were applied using a universal test machine. The amount of residual adhesives was determined through adhesive remnant index scoring. Scanning electron microscopy (SEM) images were examined to determine the effects of solvents on the enamel surface. In all test groups, the highest SBS values were found in the ethanol 5- and 15-minutes groups. SEM examination showed micro-cracks in all groups. Increased SBS values were also found in 5- and 15-minutes groups of hot water and DMSO, while both peppermint oil groups had similar SBS values as the control group. SBS values of both acetone 5- and 15-minutes groups were found to be lower than the control and other groups. Acetone application for 5 or 15 minutes before debonding of ceramic brackets could be an alternative clinical approach to prevent enamel damage and facilitate debonding.

Effectiveness of surface polishing after debonding of metal brackets from different CAD-CAM materials.

The purposes of this study were to compare and evaluate the surface texture of different restorative computer-aided design and computer-aided manufacturing (CAD/CAM) materials before bonding and after debonding of metal orthodontic brackets. Atotal of 60rectangular ceramic test specimens (n = 20 in each group) were prepared using feldspathic ceramic blocks (FLD; served as control), hybrid ceramic blocks (HC), and lithium disilicate ceramic blocks (LDC). Surface roughness (Ra) analysis was conducted using aprofilometer before bonding the metal brackets. After the debonding and polishing procedures, asecond surface roughness analysis was conducted on each specimen. The shear bond strength (SBS) test was applied to each specimen using auniversal test machine for debonding the metal brackets. The debonded specimens were examined under astereomicroscope and scored using a4-step adhesive remnant index (ARI). The Ra and SBS values and the ARI scores were saved, and the data were analyzed statistically at asignificance level of 0.05. One specimen from each group was examined under atomic force microscopy to visualize surface roughness. Furthermore, one specimen from each group was additionally prepared for scanning electron microscopy analysis. Statistically significant differences in SBS measurements were observed between all three groups. The highest SBS values were obtained from the FLD group, the lowest from the LDC group. The HC group showed significantly (P = 0.001) lower Ra values than the LDC and FLD groups after debonding and polishing. No significant differences were observed in the ARI scores between the groups. Hybrid ceramics could be asuitable alternative for fixed restorations in adult patients receiving subsequent treatments with fixed orthodontic appliances.