In vitro evaluation of repair bond strength of composite: Effect of surface treatments with bur and laser and application of universal adhesive

Effects of different surface treatments on surface topography and bond strength in the repair of fiber-reinforced dentin composite

OBJECTIVE

This study aimed to evaluate the effects of different surface treatments on the repair bond strength between a fiber-reinforced dentin composite and a posterior composite.

METHODS

Forty fiber-reinforced dentin composite resin blocks (4 mm × 4 mm × 4 mm) were separated into eight groups (n = 5) according to the surface preparation methods: (G1) negative control group, (G2) adhesive application, (G3) 50% dimethylsulfoxide (DMSO) application, (G4) 50% DMSO + adhesive application, (G5) 37% phosphoric acid etch + adhesive application, (G6) air abrasion + adhesive application, (G7) 37% phosphoric acid etch + 50% DMSO application + adhesive application, and (G8) air abrasion +50% DMSO application + adhesive application group. The composite surfaces were repaired in two layers with a posterior composite. Composite sticks were subjected to a micro tensile bond strength (μTBS) test. Fractured surfaces were evaluated using a stereomicroscope (×25). Short fiber-reinforced composite samples' surfaces were investigated by scanning electron microscope (SEM). Shapiro Wilk, one-way ANOVA, and Tukey HSD tests were used for statistical evaluation.

RESULTS

The highest average (μTBS) values were observed in G8, whereas the lowest mean μTBS values were evident in the G1 group. Statistically significant μTBS values were found in all adhesive-applied groups when compared with the negative control group. Notably, the application of 50% DMSO without adhesive did not lead to a statistically significant increase in μTBS values. SEM images demonstrated that acid etching partially eliminated residues on the composite surface, while air abrasion had a detrimental effect on the integrity of fiber structures.

CONCLUSION

In the repair of fiber-reinforced dentin composite with a posterior composite, adhesive application is an effective approach. The treatment of 50% DMSO without adhesive did not confer a statistically significant advantage, and the supplemental use of acid etch or air abrasion did not show an additional benefit compared to adhesive-only repairs.

CLINICAL SIGNIFICANCE

Adhesive application emerges as a potent and effective strategy for the repair of bur-roughened fiber-reinforced dentin composites. With its limitations, the study highlights the efficacy of adhesive-only repairs without the necessity for additional surface treatments.

The Effect of Mechanical Alteration on Repair Bond Strength of S-PRG-Filler-Based Resin Composite Materials

This study investigates the impact of mechanical alteration on resin composite surfaces and its subsequent effect on repair bond strength. A total of 100 resin composite disks were prepared and were allocated for 24 h or 1 year of artificial aging. Specimens were embedded in epoxy resin, and the composite surfaces were mechanically altered using either diamond burs or air abrasion with aluminum oxide or glass beads. A universal bonding material was applied and a 2 mm circular and 3 mm high repair composite cylinder were prepared using a Teflon mold. Then, the specimens were tested for their shear bond strength, and the de-bonded specimens were observed under a scanning electron microscope to determine the failure pattern. SPSS 26.0 statistical software was used to analyze the data. Two-way ANOVA showed a statistically significant effect of mechanical alteration and aging on the shear bond strength of S-PRG-filler-based resin composite (p < 0.05). Surface modification with a fine diamond bur showed a significantly higher bond strength in both 24-h- and 1-year-aged specimens. Surface modification with alumina significantly increased the bond strength of 1-year-aged specimens; however, it was statistically insignificant for 24 h-aged specimens. Mechanical alteration with a fine diamond bur and 50-micron alumina can improve the repair bond strength of the composite.

Scoping review: Effect of surface treatments on bond strength of resin composite repair

OBJECTIVE

to evaluate the existing evidence on surface treatment techniques employed in resin composite repair and their effect on the repair short- and long-term bond strength.

DATA AND SOURCE

This scoping review was performed under the PRISMA-ScR guidelines for scoping reviews and registered on the Open Science Framework platform.

STUDY SELECTION

A systematic search was conducted in PubMed, Embase, and Scopus and grey literature up to September 2022 without language or date restriction. In vitro studies comparing mechanical surface and/or chemical treatments on repair bond strength of resin composite were included. Studies evaluating experimental adhesive systems or resin composites were excluded. Selection of studies and data extraction were performed. Data from selected studies was qualitatively analyzed.

RESULTS

A total of 76 studies were included in the qualitative analysis. Among the mechanical treatments, alumina blasting was the most frequently used, followed by silica coating and diamond bur. As for chemical treatments, dentin bonding systems were the most frequently evaluated, followed by universal adhesive systems and silane/ceramic primer. The combination of mechanical and chemical pre-treatments increased the repair bond strength of resin composite in both short- and long-term simulated aging scenarios. The evidence obtained from the included studies was classified as moderate quality, mainly due to the medium risk of bias observed across most of the studies.

CONCLUSION

The techniques used to treat the surface of resin composites for repair are diverse. Incorporating a combination of mechanical and chemical pre-treatments resulted in superior repair bond strength of resin composite materials under both short- and long-term simulated aging conditions.

CLINICAL SIGNIFICANCE

The analysis of evidence revealed significant variability among protocols for repairing resin composites. Utilizing both mechanical and chemical pre-treatment methods is important for enhancing the bond strength of resin composites during both short- and long-term simulated aging situations.

Evaluation of repair bond strength of a dental CAD/CAM resin composite after surface treatment with two Er,Cr:YSGG laser protocols following artificial aging

The aim of the present study was to evaluate the impact of two Er,Cr:YSGG laser surface treatments on the repair bond strength of a dental CAD/CAM resin composite (Brilliant Crios) after artificial aging. Twenty-four resin-based CAD/CAM blocks were cut and 48 rectangular slabs (3 x 12 x 14 mm) were prepared. Preliminary SEM observations indicated the most favorable laser settings regarding surface modification of the tested restorative material. The CAD/CAM specimens were then divided into 4 groups (n=12) based on their surface pretreatment: no treatment, air abraded with 50-μm Al2O3 particles, and laser irradiated with two different protocols using Er,Cr:YSGG laser with average power 3.5 and 4.5 W, pulse repetition rate 35 and 50 Hz, and pulse energy 100 and 90 mJ, respectively. After surface treatments each group followed a bonding protocol with silane and a flowable resin composite was used to prepare 48 microrods. Half of the microrods of each group were subjected on shear bond strength (SBS) test (chisel-shaped blade, load cell of 500 N, crosshead speed of 1 mm/min) after 24 h, while the other half underwent artificial aging (15,000 cycles, 5-55 °C) and then SBS test. The debonded specimens were examined under an optical microscope to determine the failure mode. All specimens were also evaluated using SEM to assess the surface topography after the treatments. The results showed that SBS significantly decreased after thermocycling in all the experimental groups (p<0.05). Control group presented much lower SBS values than the other groups after both 24 h and thermocycling (p<0.05). The highest values of SBS exhibited air-abrasion group (p<0.05), followed by the two laser groups, which did not differ to each other (p>0.05). The results of the current study indicated that Er,Cr:YSGG laser irradiation can be an alternative treatment for repairing the tested resin-based CAD/CAM restorative material.

Analysis of the Temperature Elevation of the Dual-Wavelength Diode Laser and the Er, Cr: YSGG Laser in Oral Soft Tissue Incisions

Introduction: Lasers are one of the most advantageous tools that have been used in a variety of medical fields. Soft tissue management is an important part of oral and maxillofacial surgery. There are different surgical procedures for management; one of them is laser surgery. The purpose of this study was to compare the dual-wavelength diode laser and the Er, Cr: YSGG laser to choose the most effective laser for a soft tissue incision in oral and maxillofacial surgery regarding temperature elevation. Methods: A dual-wavelength diode laser (810 and 980 nm) with 1.5 W and 2.5 W power outputs and an Er, Cr: YSGG (2780 nm) with 2.5 W and 3.5 W power outputs were used to make 50 incisions in six freshly dissected sheep tongues. The temperature means were measured at initial, maximum temperatures, as well as the temperature rise (difference between initial and maximum), and all were compared between the groups of soft tissue. Results: The lowest mean temperature rise was observed with a 2.5 W Er, Cr: YSGG laser, and the highest mean temperature rise was observed with a 2.5 W diode laser, and all samples from the two lasers showed a statistically significant difference (P<0.05) in the temperature rise except the 1.5 W diode, which is higher but not statistically significantly different from the 3.5 W Er, Cr: YSGG laser (P=0.100). Conclusion: The power output of 2.5 W of an Er, Cr: YSGG laser produced low levels of temperature rise compared to a diode laser and produced surgical incisions with a lower probability of heat damage to surrounding tissues.

The effect of different energy levels of the Er: YAG laser on the repair bond strength of a nanohybrid composite resin

This study evaluates the durability of repair microshear bond strength (µSBS) of nanohybrid composite resins which surfaces are treated with different laser parameters and bur. A total of 240 nanohybrid composite resin disk shaped specimens were prepared. Then, specimens were divided into eight test groups as regards to surface treatment types (Erbium (Er:YAG) laser with seven different parameters and bur). Half of the specimens in each group were subjected to 5000 thermal cycling (TC) and the other half to 20,000 TC. Universal testing machine was used for µSBS test. The data were analyzed with a two-way analysis of variance and Tukey test. Among the specimens treated with ER:YAG laser+5000 TC, we detected the highest mean µSBS test values in the subgroups L200 and L250. Among the specimens treated with ER:YAG laser+20,000 TC, the highest mean µSBS test values were seen in the L200 subgroup. The µSBS values after the 20,000 TC were significantly lower than those after 5000 TC for all different treatment types. Thermal cycling and laser energy levels have effects on repair µSBS. Considering the bond strength and durability it seems more effective to use Er:YAG laser at 200 mJ. To repair an aged nanohybrid composite resin, Er:YAG laser surface treatments may provide some benefits by acquiring a reliable bond strength with durability. This study may give information on which parameters are more suitable to use Er:YAG laser for the repair of nanohybrid composite resins.

Evaluation of the Combination of CO2 Laser and Bifunctional Bonding Agents for Composite Resin Repairs After 1 Year of Aging

Objective: to evaluate the bond strength of repairs to composite resin restorations treated with CO₂ laser and bifunctional monomers after 1 year of aging. Background: Adequate bond strength between a composite restoration and resin repair agent can be achieved through mechanical and/or chemical treatment. However, the longevity of such repairs is unknown. Methods: Resin blocks (volume: 125 mm³) were created. Failure surfaces were either not treated or were treated before the repair with a universal adhesive, a silane bonding agent and/or CO₂ laser. The blocks were distributed into six groups (n = 6 per group): resin+resin group (RRG), universal adhesive+resin group (ARG), silane+universal adhesive group (SAG), laser+silane+universal adhesive group (LSAG), laser+universal adhesive group (LAG), and laser+silane group (LSG). After treatment, repairs were made with another resin composite. "Sticks" (1.0 mm² in area and 1.0 cm in length) were cut from the specimens in each group and immersed in distilled water at 37°C. Microtensile bond strength was evaluated after 1 year of aging. Bond strength values were compared using the Kruskal-Wallis test and Dunn's test. Results: Bond strength was significantly higher in the LSAG compared with the RRG, adhesive system, LSG, whereas statistically similar results were found for the SAG, LSAG, and LAG. Bond strength was lowest in the RRG. The LSAG and LAG presented predominantly cohesive fractures. Conclusions: The bond strength of composite resin repairs was satisfactory over time. Treatment with CO₂ laser contributed to the maintenance of bond strength during the 1-year storage period and bifunctional monomers present in the universal adhesive on the irradiated repair surface were of fundamental importance to the maintenance of bond strength values, as demonstrated by microtensile bond test and fracture pattern analysis.

Effect of Different Surface Treatments on the Long-Term Repair Bond Strength of Aged Methacrylate-Based Resin Composite Restorations: A Systematic Review and Network Meta-analysis

This systematic review and network meta-analysis is aimed at investigating the effect of common surface treatments on the long-term repair bond strength of aged resin composite restorations and to rank and compare these surface treatments. In vitro studies evaluating the methacrylate-based resin composites subjected to rigorous aging protocols before and after being repaired with a new composite were included. A frequentist network meta-analysis was carried out using a random effects model. P scores were used to rank the efficacy of the surface treatments. Also, the global and node-split inconsistencies were evaluated. Web of Science, PubMed/Medline, Scopus, and Embase databases were searched until July 07, 2022. Twenty-six studies were included in the meta-analysis. The results showed that the application of silane and a total-etch (shear MD 32.35 MPa, 95% CI: 18.25 to 46.40, P score 0.95; tensile MD 33.25 MPa, 95% CI: 25.07 to 41.44; P score 0.77) or a self-etch (shear MD 38.87 MPa, 95% CI: 21.60 to 56.14, P score 0.99; tensile MD 32.52 MPa, 95% CI: 23.74 to 41.29; P score 0.73) adhesion protocol subsequent to the roughening with diamond bur produced the highest (micro)tensile and (micro)shear bond strengths compared to diamond bur alone as the control group. There was no difference between self- and total-etch adhesive protocols. Mechanical surface treatments yielded greater bond strength when used alongside the chemical adhesive agents. Further, it is possible to achieve acceptable repair bond strength using common dental clinic equipment. Therefore, clinicians could consider repairing old resin composites rather than replacing them.

Microtensile Repair Bond Strength of a Composite After Accelerated Artificial Aging: Effect of the Air Abrasion, Bur, Er:YAG Laser, Two-Step Self-etch Bonding, and Universal Bonding Repair System

Introduction: Repair of old composite restorations is a conservative approach. This study sought to compare the effects of two adhesive systems on the bond strength of repaired composites prepared by three different surface treatments: erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation, air-abrasion, and bur preparation. Methods: Eight microhybrid (Polofil Supra, VOCO, Germany) composite resin blocks were fabricated. The blocks were aged and assigned to four groups as stated by the surface treatment: (I) air-abrasion (50 µ aluminum oxide particles), (II) diamond bur (fine grit), (III) Er:YAG laser (3 W output power, 300 mJ energy) and (IV) control. After surface treatment, the blocks were acid-etched and salinized. Each group was divided two subgroups, and the Clearfil SE Bond or All-Bond Universal was applied on their surface. Composite resin was bonded to the aged composites. The blocks were cut into eight samples, and the microtensile bond strength (MTBS) was measured. Results: The maximum MTBS was noted in the air-abrasion (25.1+6 MPa) group, followed by the Er:YAG laser (21.2+4.7 MPa). The mean MTBS in laser and air-abrasion groups was significantly higher than that in other groups (P<0.05). The mean MTBS was not significantly different between the laser and air-abrasion groups (P>0.05). Composite resin conditioning by All-Bond Universal in laser and air-abrasion groups yielded significantly higher MTBS than the Clearfil SE Bond (P<0.05). Conclusion: All surface treatments created acceptable bond strength. The surface treatment of the aged composite by the Er:YAG laser or air-abrasion along with the application of silane and All-Bond Universal provide high bond strength.

Effect of surface treatment with laser on repair bond strength of composite resin to ceramic

BACKGROUND

Small chipping or fracture of ceramic restorations may be repaired by composite resin instead of replacing the restoration. This method is faster and cheaper compared to restoration replacement. Several strategies have been suggested to obtain a high repair shear bond strength (SBS). This study aimed to assess the efficacy of some new ceramic surface treatments (laser and universal adhesive) to enhance the repair bond strength of composite resin to ceramic compared to the conventional method.

MATERIALS AND METHODS

This in vitro study evaluated 80 IPS Empress Esthetic ceramic plates in eight groups (n = 10). The ceramic surface was polished with 320-grit silicon carbide paper under running water, rinsed with water spray for 10 s and dried. The samples were then divided into two subgroups for mechanical surface preparation with hydrofluoric (HF) acid and Er: YAG laser (2 W, 200 m J, 10 Hz, 10 s). Each group was divided into two subgroups for use/no use of silane. The conventional or universal adhesive was then applied on the samples in each subgroup. Composite cylinders were bonded to the ceramic surface using plastic tubes. The samples were stored in distilled water at 37°C for 24 h and subjected to an SBS test. Data were analyzed using one-way ANOVA (P < 0.05).

RESULTS

The interaction effect of variables on SBS was significant. Maximum SBS was noted in HF acid + silane + conventional adhesive group (mean: 12.0481 MPa). Minimum SBS was noted in the laser + conventional adhesive group (mean: 2.5766 MPa). Surface treatment with HF acid yielded significantly higher SBS than laser (P < 0.001). The interaction effect of conventional/universal adhesive and use/no use of silane on SBS was statistically significant.

CONCLUSION

The repair SBS was higher in groups treated with HF acid compared to laser. Ceramic surface treatment with HF plus silane plus conventional adhesive yielded a higher SBS as well as HF plus Universal adhesive. Thus, the application of silane as a separate step can be omitted in the repair of ceramic restorations with universal adhesives.

Surface treatments on repair bond strength of aged resin composites

Aims:

The aim was to evaluate the effect of different surface treatments on the repair shear bond strength of aged resin composites.

Materials and Methods:

Forty cylindrical-shaped specimens were treated from each material: Tetric Evo Ceram, Neo Spectra, and Filtek Ultimate Universal Restorative and allocated into four groups according to the surface treatment planned to use: Group 1: diamond, Group 2: silica coating, Group 3: carbide burs, and Group 4: control group. Following the surface treatment, composites were repaired with flowable resins. The shear bond strength was tested using a universal testing machine at a crosshead speed of 0.5 mm/min. The fracture mode was assessed under 50× magnification. The data were analyzed statistically using a two-way analysis of variance (ANOVA) test followed by a one-way ANOVA test. Multiple comparison procedures were performed using Tukey’s test. The level of significance was set at P < 0.05.

Results:

The lowest mean value of the shear bond strength was for the Filtek Ultimate Universal Restorative in the control group, whereas the highest mean value was in the silica group. Silica and carbide groups had significantly higher mean values of the shear bond strength than diamond and control groups in Tetric EvoCeram and Filtek Ultimate Universal Restorative. In contrast, in Neo Spectra St HV, the carbide group had a higher mean value but was not statistically significant.

Conclusion:

Combinations of mechanical and chemical retentive systems enhance the shear bond strength of the repair composite to the aged composite. Among the different surface treatments employed in this study, silica and carbide groups show higher repair bond strength of new composite to aged composite.

In vitro evaluation of shear bond strength of orthodontic metal brackets to aged composite using a self-adhesive composite: Effect of surface conditioning and different bonding agents

OBJECTIVES

Bracket bonding to composite surfaces is increasing. This study sought to assess the effect of different adhesives (acid etchant+Transbond XT™, acid etchant+Vertise Flow™, Vertise Flow™) with different surface treatments (no preparation, bur, sandblasting, Er:YAG laser) on shear bond strength (SBS) of metal brackets to aged composite.

MATERIALS AND METHODS

In this in vitro, experimental study, Filtek™ Z250 composite discs were fabricated (10×4mm). After thermocycling (10,000 cycles between 5-55°C), the samples were randomly divided into three groups (n=48) based on the type of adhesive namely acid etchant+Transbond XT™, Vertise Flow™, and acid etchant+Vertise Flow™. Samples in each group were randomly divided into four subgroups (n=12) based on the surface treatment including no-treatment, diamond bur, sandblasting and Er:YAG laser. Samples in each group were randomly divided into three subgroups (n=12) based on the type of adhesive namely acid etchant+Transbond XT™, Vertise Flow™, and acid etchant+Vertise Flow™. After bracket bonding to composite discs, the samples underwent thermocycling (5000 cycles between 5-55°C), and their SBS was measured in a universal testing machine. The samples were then inspected under a stereomicroscope at x10 magnification to determine their mode of failure and adhesive remnant index (ARI).

RESULTS

No significant difference was noted in SBS between adhesives in no-preparation and laser groups (P>0.05). In all adhesive groups, sandblast had highest SBS, but it was not significantly different in Vertise Flow™ groups, with and without etching. The SBS provided by acid etchant+Transbond XT™ was significantly higher than that of the other two adhesives (P<0.05). The SBS of sandblasted samples was significantly higher compared with other surface treatments in all adhesive subgroups (P<0.05).

CONCLUSION

Bracket bonding to aged composite using Vertise Flow™ with or without surface treatment can serve as an alternative to the conventional orthodontic adhesives.

Universal dental adhesives: Current status, laboratory testing, and clinical performance

Increasing demand for simplified and user-friendly adhesive systems has led to the development of a new class of adhesives termed as Universal Adhesives (UAs). The term "Universal" reflects manufacturers' claims that these adhesives can be applied with any adhesion strategy and offer the versatility of use with a variety of direct and indirect restorative materials. The aim of this review was to synthesize the literature regarding the current status of UAs, their adhesion potential to various substrates and their performance in different restorative situations. In vitro studies, clinical trials and systematic reviews were identified utilizing controlled vocabulary and keyword searches in Medline and EMBASE databases. About 282 studies (272 in vitro studies; 11 clinical studies) were included. Available laboratory and clinical evidence does not support the claim that UAs can be used with any adhesive strategy. Although, they can chemically bond to various tooth and direct/indirect restorative substrates, the stability of this bond is material-dependent and subject to hydrolytic degradation. Hence, additional measures are still needed to ensure long-term durability. which undermines the versatility of UAs. The lack of long-term data regarding the clinical performance of UAs further complicates clinical decision-making. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2121-2131, 2019.