Browsing by Author "Alhijji, Saleh"

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    Influence of toothbrush abrasion and surface treatments on the color and translucency of resin infiltrated hybrid ceramics
    (The Korean Academy of Prosthodontics, 2021) Labban, Nawaf; Al Amri, Mohammad; Alhijji, Saleh; Alnafaiy, Sarah; Alfouzan, Afnan; Iskandar, Mounir; Feitosa, Sabrina; Biomedical Sciences and Comprehensive Care, School of Dentistry
    Purpose: The study compared the color change, lightness, and translucency of hybrid resin ceramics exposed to toothbrush abrasion and surface treatment. Materials and methods: Four hybrid ceramics [Lava Ultimate (LU), Vita Enamic (EN), Shofu HC (SH), and Crystal Ultra (CU)] were compared with a glass-ceramic (Vita Mark II) control. One hundred and twenty specimen blocks were prepared using a precision saw machine. Specimens in each material were divided into four subgroups based on the surface treatment (polishing or staining) and a storage medium (water or citric acid). Simulated tooth brushing with a mixture of 100 RDA (radioactive abrasives) with 0.3 ml distilled water was used for 3650 cycles (7300 strokes) for each specimen. Measurements for the color change, lightness, and translucency were measured after toothbrushing using a spectrophotometer. Statistical analysis compared outcomes using paired t-test, ANOVA, and Tukey post hoc test. Results: The maximum color change was identified in SH (stained acid) [1.44 (0.40)], whereas the lowest was identified in EN (polished water) [0.66 (0.16)] material. The maximum and minimum loss of surface translucency was observed in SH (polished water) [12.3 (0.52)] and EN (stained acid) [6.5 (0.55)] specimens, respectively. Lastly, loss of lightness was the highest in VM (polished acid) [69 (0.95)], whereas the lowest was observed in CU (stained water) [56.7 (0.86)]. Conclusion: The comparison presented a significant effect of toothbrush abrasion on translucency and lightness of the hybrid resin ceramics. Color change was not significantly influenced irrespective of the storage medium employed. Surface staining demonstrated the preservation and stability of color and optical properties under the influence of toothbrush abrasion and chemical trauma.
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    Release and MMP-9 Inhibition Assessment of Dental Adhesive Modified with EGCG-Encapsulated Halloysite Nanotubes
    (MDPI, 2023-03-09) Alhijji, Saleh; Platt, Jeffrey A.; Alhotan, Abdulaziz; Labban, Nawaf; Bottino, Marco C.; Windsor, L. Jack; Biomedical Sciences and Comprehensive Care, School of Dentistry
    Degradation of the collagen fibrils at the dentin-resin interface by the enzymatic activity of matrix metalloproteinases (MMPs) has been known to permit some dental restoration complications, such as microleakage, secondary caries, and, ultimately, restoration failures. This study aimed to evaluate a modified adhesive by adding an MMP inhibitor from green tea extract with and without nanotube encapsulation to sustain the drug release. Epigallocatechin-3-gallate (EGCG) and Halloysite nanotubes (HNTs) were prepared to produce three variant combinations of modified adhesive (EGCG, EGCG-encapsulated HNT, and EGCG-free HNT). The drug loading efficiency and EGCG release over time were evaluated using UV-vis spectrometry. MMP-mediated β-casein (BCN) cleavage rate assays were used to determine the ability of the EGCG in eluates of the adhesive to inhibit MMP-9 activities. For up to 8 weeks, HNT encapsulation reduced release to a statistically significant level. MMP-mediated β-casein cleavage rate assays showed a significant decrease for the EGCG groups compared to the non-EGCG adhesive groups. Furthermore, the use of HNT for EGCG encapsulation to modify a dental adhesive helped slow down the rate of EGCG release without impacting its MMP inhibitory capabilities, which may help to maintain the dentin-resin interface's integrity over the long term after dental restoration placement.