Objective: To compare the effects of different treatment methods used for the enamel damage, on the shear bond strength (SBS) and fracture mode of orthodontic brackets.
Materials And Methods: Freshly-extracted 140 premolars were randomly allocated to seven groups: Group I was considered as the control of other groups. The remaining groups were exposed to demineralization. In group II, brackets were directly bonded to the demineralized enamel surface. CPP-ACP paste (GC Tooth Mousse), fluoride varnish (Bifluorid 12), microabrasion with a mixture prepared with 18% hydrochloric acid and fine pumice powder, microabrasion with an agent (Opalustre) and resin infiltrant (Icon®) were applied in Groups III, IV, V, VI and VII, respectively. The specimens were tested for SBS and bond failures were scored according to the Adhesive Remnant Index (ARI). Analysis of variance and Tukey tests were used to compare the SBS of the groups. ARI scores were compared with G-test. The statistical significance was set at p < 0.05 level.
Results: Statistically significant differences were found among seven groups (F = 191.697; p < 0.001). The SBSs of groups I (mean = 18.8 ± 2.0 MPa) and VII (mean = 19.1 ± 1.4 MPa) were significantly higher than the other groups. No statistically significant difference was found between groups IV (mean = 11.5 ± 1.2 MPa) and V (mean = 12.6 ± 1.5 MPa). The differences in ARI scores of the groups were statistically significant (p < 0.01).
Conclusions: All demineralization treatment methods improve bonding to demineralized enamel. Resin infiltrant application after demineralization showed similar bond strength values as intact enamel.
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http://dx.doi.org/10.3109/00016357.2014.982703 | DOI Listing |
ACS Appl Mater Interfaces
December 2024
Department of Aerospace Engineering, Iowa State University, Ames, Iowa 50014, United States.
Using an interatomic potential that can capture the tetrahedral configuration of water molecules (HO) in ice without the need to explicitly track the motion of the O and H atoms, coarse-grained (CG) atomistic simulations are performed here to characterize the structures, energy, cohesive strengths, and fracture resistance of the grain boundaries (GBs) in polycrystalline ice resulting from water freezing. Taking the symmetric tilt grain boundaries (STGBs) with a tilting axis of ⟨0001⟩ as an example, several main findings from our simulations are (i) the GB energy, , exhibits a strong dependence on the GB misorientation angle, θ. The classical Read-Shockley model only predicts the - θ relation reasonably well when θ < 20° or θ > 45° but fails when 20° < θ < 45°; (ii) two "valleys" appear in the -θ landscape.
View Article and Find Full Text PDFJ Stomatol Oral Maxillofac Surg
December 2024
Reader, Department of Periodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai 600077, Tamil Nadu, India.. Electronic address:
Purpose: This in-vitro study aimed to compare the shear bond strength (SBS) of cobalt-chromium (Co-Cr) crowns on Corticobasal® implant abutments, evaluating the effects of two surface treatments and two luting agents.
Materials And Methods: Thirty Co-Cr crowns were fabricated using CAD-CAM technology with a direct metal laser sintering process and divided into three groups based on surface treatment: Group I (untreated), Group II (sandblasted with 50 μm Al₂O₃), and Group III (Er: YAG laser etching). Each group was further subdivided based on luting cement: Sub group A (GC Fuji Plus) and Sub group B (Rely X U200).
Appl Ergon
December 2024
Faculty of Health Sciences and Medicine, Bond University, Gold Coast, QLD, 4226, Australia; Tactical Research Unit, Bond University, Gold Coast, QLD, 4226, Australia.
Introduction: The aim of this review was to identify, collect, appraise, and synthesise research profiling paramedic job tasks, injuries sustained, and current fitness levels, to guide optimal workplace performance and enhance injury mitigation efforts.
Methods: Following the Preferred Reporting Items for Scoping Reviews, four databases (PubMed, SPORTdiscus, CINAHL, and Embase) were searched using key search terms (derivatives of 'paramedic' and 'injury', 'physical fitness' and 'tasks'). Identified records were screened against eligibility criteria with remaining studies critically appraised.
Heliyon
December 2024
Department of Advanced General Dentistry, Faculty of Dentistry, Mahidol University, Bangkok, 10400, Thailand.
Objective: The purpose of this study was to examine the effect of several antiseptic mouthwashes on the dentin microtensile bond strength of self-etch adhesive, considering the influence of rinsing with water.
Methods: Forty flat dentin surfaces were produced by sectioning sound extracted third molars. They were randomly divided into four main groups: (1) artificial saliva (control); (2) 1 % hydrogen peroxide; (3) 0.
Nanotechnology
December 2024
Donghua University, 1882 West Yan'an Road, Shanghai, 200051 , CHINA.
To advance the industrialization of flexible strain sensors, an innovative flexible sensing fiber was developed through a sophisticated wet spinning process. Silver trifluoroacetate (C2AgF3O2) and graphene oxide (GO) were combined with thermoplastic polyurethane (TPU) to prepare the fibers via wet spinning. Ascorbic acid (L-AA) was used to in situ reduce the silver trifluoroacetate and graphene oxide within the polyurethane, causing the growth of silver nanoparticles to bond with reduced graphene oxide, forming a dual conductive pathway.
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