- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Effect of Er:YAG laser on debonding strength of laminate veneers
摘要： Objective: The purpose of this study was to evaluate the debonding strength of laminate veneers after using erbium?doped: yttrium aluminium garnet (Er:YAG) laser. Materials and Methods: A total of 60 bovine mandibular incisor teeth were divided into two groups (n = 30). Cylindrical specimens (0.7 mm × 5 mm) were fabricated from Empress II ceramic. Then, they were cemented to incisors using dual?cured resin cement (Variolink II). In the first group, no laser application was performed. The Er:YAG laser was applied on each laminate veneer at the test group for 9 s by using the scanning method. Shear force to remove the laminate veneers were applied with universal testing machine at a crosshead speed of 1 mm/min. Results: Results of this study exhibited significant differences between the control (27.28 ± 2.24 MPa) and test group (3.44 ± 0.69 MPa) (P < 0.05). Conclusion: This study shows that application of Er:YAG laser decreased the bond strength of laminate veneers.
关键词： Debonding,shear bond strength,scanning method,erbium-doped:yttrium aluminium garnet laser,laminate veneers
更新于2025-09-16 10:30:52
-
Effect of acid etching, Er, Cr: YSGG laser conditioning and combining on shear bond strength of orthodontic metal bracket
摘要： Aim The present study aims to evaluate the shear bond strength and the adhesive remnants index (ARI) of metal brackets. For this purpose, enamel etched with acid, Er; Cr: YSGG (2780 nm) laser, and a combination of them. Methods In this study, 60 human premolars were divided into three groups (acid, Er, Cr: YSGG (2780 nm) laser, and combined etching). Each group contains 20 teeth. For testing of shear bond strength (SBS), the force applied by a universal testing machine. All the samples were examined under a light stereomicroscope to determine the bond failure mode. Results The results revealed that the laser-acid group had the maximum mean shear bond strength while the acid group had the minimum shear bond strength. The values of mean shear bond strength obtained of 25.90, 16.94, and16.60 MPa for laser-acid, laser, and acid, respectively. Laser and acid groups were negligibly different from each other, while they were significantly different from the lasers–acid group (p < 0.05). Regardless of the preparation of the enamel, bond failure occurred predominantly in the enamel-adhesive site. Conclusions Er, Cr: YSGG (2780 nm) laser conditioning in combination with acid led to high shear bond strength, but the hazardous effect on tooth should be considered. The bond failure mode was almost similar among all three groups, where there was no adhesive left on the surface of the tooth.
关键词： Er,Shear bond strength,Orthodontic bracket,Cr: YSGG laser,Acid etching
更新于2025-09-12 10:27:22
-
Assessment of microcracks and shear bond strength after debonding orthodontic ceramic brackets on enamel priorly etched by different Er,Cr:YSGG and Er:YAG laser settings without acid application: An in vitro study
摘要： Background data > Enamel microcrack formation has a high incidence after mechanical debonding of ceramic brackets. This may be due to high delivered shear bond strength values when enamel is priorly etched by phosphoric acid. It is still not well elucidated in the literature if laser etching affects enamel the same way. The aim of the research was to analyze different Er,Cr:YSGG and Er:YAG laser etching settings as an alternative to phosphoric acid, in an attempt to prevent enamel microcrack formation during laser etching and mechanical debonding, while reducing the shear bond strength to the minimal clinical acceptable value. Materials and methods > One hundred and thirty-three teeth were randomly divided into 7 experimental groups according to their etching modalities. Settings used for enamel etching were in Er,Cr:YSGG groups: Er,Cr:YSGG (1.5 Watt, W/20 Hertz, Hz); Er,Cr:YSGG (1.5 W/15 Hz) and Er,Cr:YSGG (2 W/20 Hz) and settings used for enamel etching in Er:YAG groups were: Er:YAG (60 millijoules , mJ), Er:YAG (80 mJ) and Er:YAG (100 mJ). Group C etched with 37% phosphoric acid served as control. Microscopic analysis was performed to assess presence of enamel microcracks. Shear bond strength was evaluated after thermocycling using Weibull survival analysis. Results > All groups showed a reduction in additional microcracks after debonding when compared to control, but only group Er:YAG (60 mJ) exhibited a statistically significant difference. Groups Er:YAG (80 mJ), control and Er:YAG (100 mJ) showed respectively the highest probability of survival at various stress levels followed by groups Er:YAG (60 mJ); Er,Cr:YSGG (1.5 W/15 Hz); Er,Cr:YSGG (2 W/20 Hz) and Er,Cr:YSGG (1.5 W/20 Hz) that presented a relatively considerable risk of failure, even at low stress levels.
关键词： Shear bond strength,Microcracks,Etching,Erbium laser
更新于2025-09-12 10:27:22
-
Effect of repeated laser surface treatments on shear bond strength between zirconia and veneering ceramic
摘要： Statement of problem. Delamination failure may occur between ceramic frameworks and veneering ceramics, shortening the lifetime of ?xed dental prostheses in load-bearing areas. Purpose. The purpose of this in vitro study was to compare the effect of different repeating CO2 laser treatment methods and conventional approaches on the shear bond strength of zirconia frameworks and veneering ceramics. Material and methods. Zirconia disks (N=110) were prepared and divided into 5 groups: milling without surface treatment (group M), airborne-particle abrasion (group APA), single laser treatment (group LX1), 2 laser treatments (group LX2), and 3 laser treatments (group LX3). The specimens in the ?rst 2 groups were treated before the framework was coated using the spraying technique. Specimens in the remaining groups were coated with veneering ceramic using the spraying process, and then subjected to laser treatment. Surface roughness and topography, interface properties, phase transformation, shear bond strength, and fracture modes were investigated. Outcomes were analyzed using a pro?lometer, a scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD), a stereomicroscope, and a universal testing machine for mechanical testing. Results. The XRD showed that phase transformation from tetragonal to monoclinic occurred after airborne-particle abrasion. This phenomenon was not observed in laser-treated specimens. Groups LX2 and LX3 had the highest surface roughness values, 1.18 ±0.23 mm and 1.21 ±0.22 mm, among all groups, and group LX3 had the highest shear bond strength values for unaged and aged conditions, 32.08 ±2.45 MPa and 31.43 ±2.07 MPa. The mixed-fracture mode was the most common type of fracture observed. Conclusions. The results indicated that the shear bond strength between the zirconia framework and veneering ceramic was higher after laser surface treatments than after milling alone or after airborne-particle abrasion. Laser treatment methods, particularly LX2 and LX3, could be considered reliable approaches for zirconia surface treatment.
关键词： veneering ceramic,laser treatment,zirconia,shear bond strength,surface roughness
更新于2025-09-12 10:27:22
-
Effect of Fiber Laser Irradiation on the Shear Bond Strength between Acrylic Resin and Titanium
摘要： Objectives. The aim of this study is to investigate the shear bond strength of an acrylic resin to titanium after different surface treatment methods. Material and Methods. A total of seventy-two disc-shaped specimens (10 mm × 10 mm × 2 mm) were prepared from titanium alloy. The specimens were randomly allocated to six equal groups: Group S (sandblasting), Group MP (metal primer), Group 10W (fiber laser 10 W), Group 20W (fiber laser 20 W), Group 10WMP (fiber laser 10 W+metal primer), and Group 20WMP (fiber laser 20 W+metal primer). All of the specimens were thermocycled up to 5000 cycles. After thermal cycling, a shear bond strength test was conducted. The shear bond strength data were analyzed with one-way ANOVA and Tukey’s post hoc pairwise comparisons (p < 0 05). Results. While the highest values were determined in Group MP, the lowest values were observed in Group S. Additionally, Group MP exhibited significantly higher shear bond strength values than any of the other groups (p < 0 05) except Group 10WMP. Similar results were observed between Group MP and Group 10WMP (p > 0 05). The groups in which a metal primer was applied (Group MP, 10WMP, and 20WMP) showed significantly higher values than Group S. The shear bond strength values of Group 10W and Group 20W were similar. Conclusions. The application of a metal primer significantly improved the bond strength of acrylic resin to titanium. Fiber laser application may be an alternative method to sandblasting for improving the bond strength of acrylic resin to titanium.
关键词： acrylic resin,fiber laser,titanium,shear bond strength,surface treatment
更新于2025-09-12 10:27:22
-
Influence of Er,Cr:YSGG Laser Dentin Conditioning on the Bond Strength of Bioactive and Conventional Bulk-Fill Dental Restorative Material
摘要： Objective: The aim of the study was to evaluate shear bond strength (SBS) and modes of failure for bioactive (BA) material when bonded to Er,Cr:YSGG lased dentin in comparison with other conditioning regimes. Materials and methods: One hundred twenty extracted teeth were mounted and allocated into eight groups (n = 15) according to the surface conditioning [group 1: Er,Cr:YSGG laser + BA; group 2: Er,Cr:YSGG laser + multi-core (MC); group 3: Er,Cr:YSGG + Ketac Conditioner (polyacrylic acid) + BA; group 4: Er,Cr:YSGG + Ketac Conditioner + MC; group 5: conventional etch and rinse + BA (Control); group 6: conventional etch and rinse + MC (Control); group 7: self-etch + BA; group 8: self-etch + MC]. Based on the type of bulk-?ll material, samples from groups 1, 3, 5, and 7 were bonded to BA and groups 2, 4, 6, and 8 were bonded to conventional MC bulk-?ll material. All specimens were tested for SBS using universal testing machine. Ten samples from each group were assessed for modes of failure. Data were assessed using analysis of variance and Tukey multiple comparisons test. Results: The maximum SBS value was in group 6 (18.96 – 0.315) with etch and rinse dentin conditioning and bonded to MC. The minimum SBS value was exhibited by group 7 (16.04 – 0.854) self-etch conditioning bonded to BA. SBS among group 6 specimens were signi?cantly higher than that of specimens in group 7 ( p < 0.05). Among all groups the most common type of observed failure was adhesive. Conclusions: Dentin surface treatment with Er,Cr:YSGG phototherapy for the adhesive bonding of BA and conventional bulk-?ll resin composite MC showed comparable bond strength outcomes to conventional conditioning techniques. Er,Cr:YSGG laser dentin conditioning of dentin for bonding of bulk-?ll BA materials has potential to be used clinically as it shows potential for adequate adhesive bond integrity.
关键词： Er,Cr:YSGG,bioactive material,shear bond strength,failure modes,dentin conditioning
更新于2025-09-11 14:15:04
-
Effect of the Er: YAG laser on the shear bond strength of conventional glass ionomer and BiodentineTM to dentine
摘要： Objectives: The purpose of this study was to determine if Er: YAG laser etching improves the shear bond strength (SBS) of Biodentin? and GC Fuji IX? to dentine. Materials and Methods: Forty human dentine specimens were standardized and embedded in stone. The specimens were randomized into four groups (n = 10). Twenty samples were treated with the Er: YAG laser radiation and 10 of these restored with GC Fuji IX? and 10 with Biodentine?. The remaining 20 specimens acted as controls (no laser treatment); 10 were restored with GC Fuji IX? and 10 with Biodentin?. All samples were then stored in an incubator at 37.5°C and 100% humidity for 7 days. The SBS was determined using a Zwick universal testing machine. A two-way analysis of variance test was used to evaluate the statistical difference in SBS between the groups. An independent sample t?test was used to determine the statistical significance of differences between control and lased groups within the same material. Results: A highly statistically significant difference in SBS was found with the laser treatment (P = 0.0001) and material (i.e., Biodentin? or Fuji IX? (P = 0.0001). The GC Fuji IX? group recorded the highest mean SBS required to dislodge the material from the laser-treated dentine surface (1.77 ± 0.22 Mega-Pascal [MPa]). The mean SBS of Biodentin? to dentine following the laser radiation (1.12 ± 0.16 MPa) was significantly greater compared to the nonlased dentine (0.53 ± 0.09). Pearson Chi?square test indicated a nonsignificant relation between shear strength and mode of failure (P = 0.467). Conclusion: Laser etching of the dentine surfaces yielded a significant increase in the bond strength for both GC Fuji IX? and Biodentin?. The SBS of Biodentin? to dentine is greater than with conventional glass ionomer (Fuji IX?).
关键词： Biodentin?,dentin,shear bond strength,Er: YAG laser
更新于2025-09-11 14:15:04
-
A Modified Photoactivation Protocol Using Two Simultaneous Light-Curing Units for Bonding Brackets to Enamel
摘要： This study investigated the effect of a modified photoactivation protocol using two simultaneous light-curing units on the shear bond strength (SBS) of brackets to enamel. Metal brackets were bonded to bovine incisors using the resin-based orthodontic cement Transbond XT (3M Unitek). Four photoactivation protocols of the orthodontic cement were tested (n=15): Control: photoactivation for 10 s on each proximal face of the bracket at a time; Simultaneous: photoactivation for 10 s on both proximal faces of the bracket at the same time; One side-20s: photoactivation for 20 s at one proximal face of the bracket only; and One side-10s: photoactivation for 10 s only at one proximal face of the bracket. SBS was tested immediately or after 1000 thermal cycles. Adhesive remnant index (ARI) was classified. Data were subjected to two-way ANOVA and Student-Newman-Keuls’ test (α=0.05). Pooled means ± standard deviations for SBS to enamel (MPa) were: 10.2±4.2 (Control), 9.7±4.5 (Simultaneous), 5.6±3.1 (One side-20s), and 4.6±1.9 (One side-10s). Pooled SBS data for immediate and thermal cycled groups were 6.3±2.6 and 8.8±5.2. A predominance of ARI scores 1-2 and 0-1 was observed for the immediate and thermally cycled groups, respectively. In conclusion, simultaneous photoactivation of the orthodontic cement using two light-curing units, one positioned at each proximal face of the bracket, yielded similar bonding ability compared to the conventional light-curing method. Photoactivation of the orthodontic cement at one proximal face of the bracket only is not recommended, irrespective of the light-curing time used.
关键词： composite,polymerization,aging,Orthodontics,shear bond strength
更新于2025-09-04 15:30:14