The Effect of Various Lasers on the Bond Strength Between Orthodontic Brackets and Dental Ceramics: A Systematic Review and Meta-Analysis

Background/objective: This systematic review and meta-analysis aimed to assess how laser conditioning affected brackets bonded to dental ceramics' shear bond strength (SBS). Materials and methods: The study was conducted by searching Pubmed/Medline, Scopus, Embase, Web of Science, the Cochrane Library, and Google Scholar up to September 14, 2022. In addition, the reference lists of the relevant articles were checked manually. Articles that compared SBS of laser-treated feldspathic, lithium disilicate, or zirconia surfaces with other standard techniques for bonding metal or ceramic orthodontic brackets were considered. Using a random-effects model, data pooling was carried out as the weighted mean difference (WMD). Results: This study initially contained 1717 reports, and following review, 32 articles were deemed suitable for our meta-analysis. The pooling results showed that the treatments with lasers such as "Er:YAG" [WMD = -1.12 MPa; 95% confidence interval (CI): -1.93 to -0.31], "Er:YAG + Silane" (WMD = -3.08 MPa; 95% CI: -4.77 to -1.40), and "Nd: YAG + Silane" (WMD = -2.58 MPa; 95% CI: -3.76 to -1.40) had statistically significant lower adhesion values compared with controls. Contrarily, "Ti:Sapphire femtosecond" demonstrated significantly higher bonding values (WMD = 0.94 MPa; 95% CI: 0.29-1.60). In contrast, other interventions obtained no statistically significant difference in SBS. Conclusions: Most of the laser groups showed results comparable with those of conventional approaches. Although more research is necessary for definitive conclusions, laser treatment may be an effective option for treating the surfaces of ceramic materials.

Shear Bond Strength between Orthodontic Brackets and Monolithic 4Y-TZP: An In Vitro Study

The aim of this study was to evaluate the effect of different surface treatments on the shear bond strength (SBS) between metal orthodontic brackets and monolithic zirconia surfaces bonded with resin composite. Fifty monolithic zirconia (4Y-TZP) disks were sintered and glazed. Specimens were divided into five groups (n = 10) for different surface treatments: control, nano second fiber laser, sandblasting, grinding and tribochemical coating (CoJet Sand 30-μm). Metal orthodontic brackets were bonded to monolithic zirconia surface by two-component orthodontic adhesive. After 500 cycles of thermocycling, shear bond strength values were measured by a universal testing machine at a cross head speed of 0.5 mm/min. The data was recorded as MPa and statistically analyzed with One-way ANOVA, Levene's LSD tests with Bonferroni corrections. The significance level was α = 0.05. The surface topography of one specimen of each group was evaluated by scanning electron microscopy (SEM). Statistically significant difference was observed among study groups (p = 0.018). The lowest shear bond strength was observed in the control group (3.92 ± 1.9). Tribochemical coating showed the highest bond strength (7.44 ± 2.9), which was statistically different from the control and nano second laser (4.3 ± 1.4) groups but not statistically different from grinding (6.15 ± 3.1) or sandblasting (6.47 ± 3.3). SEM images showed comprehensive results of each surface treatment on monolithic zirconia. All failure modes were recorded as adhesive between the composite resin and monolithic zirconia. Based on the findings of this study, it can be concluded that grinding, sandblasting and tribochemical coating techniques showed clinically acceptable bond strength within the range of 6-8 MPa. These surface treatments can be considered suitable for achieving a durable bond between metal orthodontic brackets and monolithic 4Y-TZP ceramic surfaces.

What Is the Most Effective Technique for Bonding Brackets on Ceramic-A Systematic Review and Meta-Analysis

Background: There has been an increase in demand for orthodontic treatment within the adult population, who likely receive restorative treatments using ceramic structures. The current state of the art regarding the most effective method to achieve an appropriate bond strength of brackets on ceramic surfaces isn’t consensual. This systematic review aims to compare the available surface treatments to ceramics and determine the one that allows to obtain the best bond strength. Methods: This systematic review followed the PRISMA guidelines and the PICO methodology was used, with the question “What is the most effective technique for bonding brackets on ceramic crowns or veneers?”. The research was carried out in PubMed, Web of Science, Embase and Cochrane Library databases. In vitro and ex vivo studies were included. The methodological quality was evaluated using the guidelines for reporting of preclinical studies on dental materials by Faggion Jr. Results: A total of 655 articles searched in various databases were initially scrutinized. Sevety one articles were chosen for quality analysis. The risk of bias was considered medium to high in most studies. The use of hydrofluoric acid (HF), silane and laser afforded the overall best results. HF and HF plus laser achieved significantly highest bond strength scores in felsdphatic porcelain, while laser was the best treatment in lithium disilicate ceramics. Conclusions: The most effective technique for bonding brackets on ceramic is dependent on the type of ceramic.

Effects of Novel versus Conventional Porcelain Surface Treatments on Shear Bond Strength of Orthodontic Brackets: A Systematic Review and Meta-Analysis

BACKGROUND

Despite the importance of identifying proper novel porcelain preparation techniques to improve bonding of orthodontic brackets to porcelain surfaces, and despite the highly controversial results on this subject, no systematic review or meta-analysis exists in this regard.

OBJECTIVE

To comparatively summarize the effects of all the available porcelain surface treatments on the shear bond strength (SBS) and adhesive remnant index (ARI) of orthodontic brackets (metal, ceramic, polycarbonate) bonded to feldspathic porcelain restorations. Search Methods. A search was conducted for articles published between January 1990 and February 2021 in PubMed, MeSH, Scopus, Web of Science, Cochrane, Google Scholar, and reference lists. Eligibility Criteria. English-language articles comparing SBS of feldspathic porcelain's surface preparation methods for metal/ceramic/polycarbonate orthodontic brackets were included. Articles comparing silanes/bonding agents/primers without assessing roughening techniques were excluded. Data Analysis. Studies were summarized and risk of bias assessed. Each treatment's SBS was compared with the 6 and 10 MPa recommended thresholds. Studies including comparator (HF [hydrofluoric acid] + silane + bonding) were candidates for meta-analysis. ARI scores were dichotomized. Fixed- and random-effects models were used and forest plots drawn. Egger regressions and/or funnel plots were used to assess publication biases.

RESULTS

Thirty-two studies were included (140 groups of SBS, 82 groups of ARI). Bond strengths of 21 studies were meta-analyzed (64 comparisons in 14 meta-analyses). ARIs of 12 articles were meta-analyzed (28 comparisons in 8 meta-analyses). Certain protocols provided bond strengths poorer than HF + silane + bonding: "abrasion + bonding, diamond bur + bonding, HF + bonding, Nd:YAG laser (1 W) + silane + bonding, CO₂ laser (2 W/2 Hz) + silane + bonding, and phosphoric acid + silane + bonding." Abrasion + HF + silane + bonding might act almost better than HF + silane + bonding. Abrasion + silane + bonding yields controversial results, being slightly (marginally significantly) better than HF + silane + bonding. Some protocols had controversial results with their overall effects being close to HF + silane + bonding: "Cojet + silane + bonding, diamond bur + silane + bonding, Er:YAG laser (1.6 W/20 Hz) + silane + bonding." Few methods provided bond strengths similar to HF + silane + bonding without much controversy: "Nd:YAG laser (2 W) + silane + bonding" and "phosphoric acid + silane + bonding" (in ceramic brackets). ARIs were either similar to HF + silane + bonding or relatively skewed towards the "no resin on porcelain" end. The risk of bias was rather low. Limitations. All the found studies were in vitro and thus not easily translatable to clinical conditions. Many metasamples were small.

CONCLUSIONS

The preparation methods HF + silane + bonding, abrasion + HF + silane + bonding, Nd:YAG (2 W) + silane + bonding, and phosphoric acid + silane + bonding (in ceramic brackets) might provide stronger bonds.

Shear bond strength between gingival composite resin and glazed gingival porcelain for implant-supported prostheses

This study determined the shear bond strength (SBS) between an indirect gingival composite resin and glazed gingival porcelain after various surface treatments. A total of 176 porcelain disks with natural glazing were used and assigned to one of four groups: no surface treatment, airborne-particle abrasion, hydrofluoric acid etching, or a combination of airborne-particle abrasion followed by hydrofluoric acid etching. Each group was divided into two subgroups: one subgroup was unprimed, and the other was silanized. An indirect composite resin was then bonded to the porcelain disks. Half of the specimens in each group (n = 11) were exposed to 5000 thermocycles. SBSs were measured, and data were analyzed with the Kruskal-Wallis and Steel-Dwass tests. Among silanized specimens, those treated with the combination of airborne-particle abrasion and hydrofluoric acid etching exhibited the highest bond strengths both before and after thermocycling. However, the SBS values of the silanized and unprimed hydrofluoric acid etched specimens did not differ significantly. Airborne-particle abrasion followed by hydrofluoric acid etching with silane application yielded stronger, more durable bonds between the indirect gingival composite resin and glazed gingival porcelain.

Bond strength of metal brackets to feldspathic ceramic treated with different surface conditioning methods: an in vitro study

Purpose:

To compare MEP which is originally manufactured for increasing bond strength between organic resins and ceramic with conventional surface treatment methods in preparation of leucite-reinforced FC surfaces regarding shear bond strength (SBS) of stainless steel brackets and the mode of bond failure.

Materials and methods:

Forty specimens that were fabricated from FC material and glazed were randomly assigned to four surface conditioning methods: (1) CoJet Sand; (2) MEP; (3) HF acid etching followed by silane coupling agent; (4) Diamond bur followed by silane coupling agent. The SBS was determined using universal testing machine. Bond failure sites were classified according to Adhesive Remnant Index (ARI).

Results:

No statistically significant difference (p less than 0.05) was found in SBS between the groups while significant intergroup differences were detected concerning ARI scores (p less than 0.001). Group 1 had ARI score 1 and 2 indicating mode of failure at the adhesive interface with greater percentage of the adhesive left on bracket base. The other groups had higher frequency of ARI score 3 and 2. The quantity of the ARI retained on the ceramic surface was highest in Group 3, followed by Group 4 and Group 2.

Conclusion:

MEP can be a suitable alternative for bonding metal brackets to FC surface.

In Vitro Analysis of Quality of Dental Adhesive Bond Systems Applied in Various Conditions

Introduction: There are several methods of reducing a microleakage, and one of them is choosing appropriate adhesive material. The aim of the work was the in vitro analysis of 4 bonds: 3M ESPE “Single bond”, Dentsply “Prime and Bond Active”, Coltene “One Coat 7 Universal”, and Kuraray “Clearfil Universal Bond Quick”. Material and methods: 136 healthy molar teeth were collected and randomly split into 4 groups and Vth Class cavities were prepared. Chosen adhesives were used in four groups of teeth with the same composite. Teeth were the thermocycled, sealed, covered with lacquer, and submerged in 1% methylene blue solution for 24 h. After the thermocycling, the vertices of each tooth were sealed using dental wax. Each tooth was then fully covered with lacquer. All teeth were then submerged into 1% methylene blue solution for 24 h in room temperature. In the next step they were transversely cut through a center of restoration. The Olympus BX43 microscope was used to photograph each cut tooth. With the usage of Olympus stream software, measurement of the dye’s leakage was performed. Results. The statistical analysis proved that the most effective material when applied to ideally prepared cavity surface was Dentsply “Prime and Bond Active”. The second material was 3M ESPE “Single Bond”, third—Coltene “One Coat 7 Universal” and fourth—Kuraray “Clearfil Universal Bond Quick”. The most effective material applied to a too-dry surface was Dentsply “Prime and Bond Active”, second—3M ESPE “Single Bond”, third—Coltene “One Coat 7 Universal” and fourth—Kuraray “Clearfil Universal Bond Quick”. When it comes to too damp surfaces the best results were obtained with Dentsply “Prime and Bond Active” then Coltene “One Coat 7 Universal”, 3M ESPE “Single Bond” and Kuraray “Clearfil Universal Bond Quick”. Conclusion: The level of cavity dampness influences the quality of adhesives. Better results are obtained with over-dried surfaces than over-damp, which is connected with the dilution of the material.

The effects of different surface treatments on the shear bond strengths of two dual-cure resin cements to CAD/CAM restorative materials

PURPOSE

The aim of the present study was to investigate the effects of surface treatments on the bond strengths between polymer-containing restorative materials and two dual-cure resin cements.

MATERIALS AND METHODS

In the present study, rectangular samples prepared from Lava Ultimate (LU) and Vita Enamic (VE) blocks were used. The specimen surfaces were treated using CoJet sandblasting, 50 µm Al₂O₃ sandblasting, % 9 HF (hydrofluoric) acid, ER,Cr:YSGG laser treatment, and Z-Prime. Dual-cure resin cements (TheraCem and 3M RelyX U 200) were applied on each specimen's treated surface. A micro-tensile device was used to evaluate shear bond strength. Statistical analysis was performed using the SAS 9.4v3.

RESULTS

While the bond strength using TheraCem with LU or VE was not statistically significant (P=.164), the bond strength using U200 with VE was statistically significant (P=.006). In the TheraCem applied VE groups, Z-Prime and HF acid were statistically different from CoJet, Laser, and Sandblast groups. In comparison of TheraCem used LU group, there was a statistically significant difference between HF acid and other surface treatments.

CONCLUSION

The bonding performance between the restorative materials and cements were material type-dependent and surface treatment had a large effect on the bond strength. Within the limitations of the study, the use of both U200 and TheraCem may be suggested if Z-prime was applied to intaglio surfaces of VE. The cementation of LU using TheraCem is suitable after HF acid conditioning of the restoration surfaces.

Bond Strength of Metal and Ceramic Brackets on Resin Nanoceramic Material With Different Surface Treatments

Objective

This study aimed to evaluate the effects of different surface conditoning methods on surface texture and shear bond strength (SBS) of brackets bonded to resin nanoceramic material.

Methods

Ceramic specimens were divided into two groups as metal brackets and ceramic brackets. In each group, the following five subgroups were conditoned with orthophosphoric acid (OPA), hydrofluoric acid (HFA), silica coating with Cojet, Nd: Yag laser, and Femtosecond (Fs) laser. Extra samples were used for scanning electron microscopy and 3D profilometer evaluation.

Results

All surface conditioning methods caused optimum or higher SBS. Metal brackets had higher SBS than porcelain brackets, but this difference reached statistical significance only in Fs laser group. OPA caused surface modification comparable to HFA because of polymer content of resin nanoceramic. Although Fs laser and Cojet conditioning caused optimum or higher SBS, surface damage of these methods to the resin nanoceramic specimens clearly seen on 3D profilometer.

Conclusion

HFA and Nd: Yag laser are effective surface conditioning methods for resin nanoceramics. OPA combined with silane application caused optimum SBS and can be used as an alternative to HFA. Surface texture changes should be considered to determine surface damage while deciding the optimum surface conditioning method for ceramics other than SBS.