Effect of silane reaction time on the repair of a nanofilled composite using tribochemical treatment

Purpose: To investigate the influence of silane reaction time on the repair strength of an aged nanofilled composite and to characterize the bonding mechanism. Materials and Methods: Nanofilled composite disks (n = 110, Filtek Supreme XT) were aged for 90 days in water. After tribochemical treatment (CoJet-Sand), the specimens were assigned to 5 groups (n = 22), primed with silane (Espe-Sil), and left to react for 1, 2, 3, 4, and 5 min. A thin layer of adhesive (Visio-Bond) was applied and a new composite with the same dimension was placed and cured. Non-aged specimens immediately layered and cured using the incremental technique served as controls. After aging (30 days in water plus 5000 thermal cycles), the interface was subjected to a shearing force until failure. Failure mode was evaluated under a stereomicroscope and scanning electron microscopy (SEM). Additional aged and treated surfaces were evaluated for morphology as well as elemental and molecular composition using SEM/EDX and ATR-FTIR. Results: The mean shear bond strength (SBS) of the repaired specimens was 53.9 ± 8.6 MPa, with no significant difference among the various reaction times, but significantly lower compared to the control (88.1 ± 12.5 MPa). Tribochemical treatment created an irregular surface morphology with particles imbedded in the aged surface. Interfacial SEM/EDX analysis showed a 5-μm non-uniform high atomic number zone rich in Al and Si. Conclusion: Tribochemical treatments for repairing composite using a short silane reaction period (1 min) are equally effective as the prolonged reaction periods (2 to 5 min), yielding interfacial shear strength of ~60% of unrepaired material

The effect of enriching denture adhesives with chlorhexidine diacetate on the proliferation of Candida albicans: an in vitro analysis

Denture adhesives are widely used in dentistry. The growth of Candida albicans on the denture base is common on both jaws, particularly in elderly patients. A strong correlation has been found between the growth of Candida albicans and dentures, potentially leading to denture stomatitis. Recent studies show that the addition of chlorhexidine diacetate (CHDA) to denture adhesives can have a protective effect against denture stomatitis. The aim of this research is to examine the antifungal properties of three denture adhesives when CHDA is added. We hypothesize that the addition of CHDA to denture adhesives will result in antifungal activity against Candida albicans. Three denture adhesive materials (Corega, Protefix and Kukident) were prepared with and without the addition of CHDA in order to measure whether CHDA increased the resistance of the adhesives to the growth of Candida albicans. Dynamic and static intercellular changes were assessed through direct contact test (DCT) and confocal microscopy. The tested materials were evaluated immediately after setting and at 14 days post-setting. When combined with CHDA, all three denture adhesive materials decreased Candida albicans growth compared to the control (p less than 0.0001). This inhibition of growth was more prominent in the first 24 h. The confocal microscopy results supported the DCT findings. The addition of CHDA to denture adhesive pastes inhibits growth of Candida albicans, and may potentially reduce the incidence of denture stomatitis. Further studies are warranted