ABSTRACT
This study aimed to fabricate nano-hydroxyapatite (nHA) grafted/non-grafted E-glass-fiber-based (nHA/EG) and E-glass fiber (EG) orthodontic retainers and to compare their properties with commercially available retainers. Stainless-steel (SS) retainers and everStick Ortho (EST) were used as control groups. The retainers were evaluated with Raman spectroscopy and bonded to bovine teeth. The samples were fatigued under cyclic loading (120,000 cycles) followed by static load testing. The failure behavior was evaluated under an optical microscope and scanning electron microscope. The strain growth on the orthodontic retainers was assessed (48h and 168h) by an adhesion test using Staphylococcus aureus and Candida albicans. The characteristic peaks of resin and glass fibers were observed, and the debonding force results showed a significant difference among all of the groups. SS retainers showed the highest bonding force, whereas nHA/EG retainers showed a non-significant difference from EG and EST retainers. SS retainers' failure mode occurred mainly at the retainer-composite interface, while breakage occurred in glass-fiber-based retainers. The strains' adhesion to EST and EG was reduced with time. However, it was increased with nHA/EG. Fabrication of nHA/EG retainers was successfully achieved and showed better debonding force compared to other glass-fiber-based groups, whereas non-linear behavior was observed for the strains' adhesion.
ABSTRACT
At present, bioactive glasses (BAGs) are demonstrating promising results in the remineralization of hard tissues. Their bioactive properties can potentially overcome the demineralization effect accompanying orthodontic treatment. This review aimed to evaluate the effectiveness of bioactive glass enhanced orthodontic bonding resins on enamel remineralization, in addition to their antibacterial, ion release and acid neutralization effect. Four databases (PubMed, MEDLINE, Web of Science and Scopus) were searched. Two hundred and fifty-one full-text articles were screened independently, out of which seven studies satisfied the inclusion criteria. Quality appraisal was performed by two independent reviewers. Methodologies used to assess the anti-demineralization effect included Micro-Computed Tomography, Polarized Light Microscopy and Hardness Testing (Knoop and Berkovich). All seven articles confirmed the superior remineralization effect of BAG orthodontic bonding resins compared to their non-BAG counterparts. A proportional relationship was proved between BAG concentrations and increased anti-demineralization effect. The addition of antibacterial agents to BAG does not necessarily improve its anti-demineralization effect. Although studies have confirmed the effectiveness of BAG orthodontic bonding resins on enamel remineralization, there was a degree of heterogeneity across studies due to the lack of an in vitro studies standardized protocol.
Subject(s)
Glass/chemistry , Microscopy, Polarization , X-Ray MicrotomographyABSTRACT
INTRODUCTION: Steam heat sterilization could be one of the factors that affects the dimensional accuracy of surgical guides, leading to an error during guided implant surgery. OBJECTIVE: The purpose of this study was to investigate the effect of steam heat sterilization on the dimensional changes of surgical guides. MATERIALS AND METHODS: A total of 27 surgical guides, which were made by either Formlabs printer (Formlabs Inc., Somerville, MA) or Simplant (DENTSPLY Implants NV, Hasselt, Belgium), were scanned using an intraoral scanner before and after sterilization. The dimensional changes at the center of the implant sleeves were analyzed using the computer-aided design interactive software for 65 implant sites before and after steam heat sterilization at 121°C for 20 minutes. RESULTS: There was no significant difference between the mean x, y, and z axes of the center of the sleeves when measured before and after sterilization (P values were 0.37, 0.24, and 0.29, respectively). Nonparametric analysis showed no significant difference between the mean deviations of either surgical guide (P = 0.908). CONCLUSION: Steam heat sterilization has a nonsignificant effect on the dimensional changes of the tested surgical guides.
