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In-vitro assessment of modified resin adhesive-tooth interfaces

Objectives: This research aimed to characterize the interfacial characteristics of modified dental resin-based adhesive systems bonded to sound and carious dental tissue. The modification included the incorporation of matrix metalloproteinase (MMP) inhibitors within the primers of these adhesives. Materials and methods: Two MMP inhibitors (BB94 and GM6001) were added to three adhesive primers, Optibond FL “OB” (Kerr, USA), Prime&Bond NT “PB” (Dentsply, USA) and G-Bond “GB” (GC, UK) and bonded to sound dentine. The inhibitory effect of the modified adhesive on recombinant MMPs and on sound dentine MMPs was assessed using FRET-based measurement of MMP activity and substrate zymography, respectively. Micro-tensile bond strength and micro-permeability were used to evaluate the modified adhesives’ physical properties. Micro-Raman spectroscopy analysis was validated on carious dentine and it was used to evaluate the interface between the modified OB primer and caries-affected dentine. The inhibitory effect of the modified adhesive on caries-affected dentine was studied using in-situ zymography. Results: The fluorometric assay and zymography showed that modified adhesives had high affinity toward both synthetic FRET-peptides and dentine powder substrates, respectively. The immediate micro-tensile bond strength was enhanced for OB (48.0 MPa ± 20.3 SD for BB94 and 42.0 MPa ± 18.7 SD for GM6001) and GB (34.8 MPa ± 19.2 SD for BB94 and 41.7 MPa ± 17.6 SD for GM6001). However, no changes were detected between the control and the inhibitor groups following 3-month storage. Additionally, the micro-permeability of PB and GB showed less dye seepage, to the “hybrid layer” and to the “adhesive”, respectively. The caries-infected dentine was defined significantly by the KHN (< 20.6), AF (> 14.4 A.U.) and by the relative contribution of the mineral (< 36.4%), Porphyrin fluorescence (> 25.3%) and Infected dentine signal (> 0.3%) Raman clusters. The caries-affected dentine-adhesive interface exhibited more hydrophobic resin (32.8% ± 3.9 SD) that maintained over four-week aging. Conclusions: The addition of MMP inhibitors to contemporary dental adhesive systems resulted in modified adhesives that had an enhanced dentine-adhesive interface with inhibited MMP activity. Such properties enhance the clinical performance of adhesive systems.
Date January 2013
CreatorsAlmahdy, Ahmed
PublisherKing's College London (University of London)
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation

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