No abstract

Metal oxide-based electrochemical sensors, despite their robust redox activity, lack sufficient conductivity to overcome their sluggish kinetics. Herein, we propose a unique self-assembled hybrid configuration based on redox-active Co3O4 hexagons (Co3O4-HX) and the highly conductive, few-layer-thick Ti3C2T x sheets. The self-assembly approach enabled the compact interfacial formation and moderate intercalation of Ti3C2T x sheets, allowing the Co3O4/Ti3C2T x composite (Co3O4–MX) to exhibit a synergetic improvement in the charge-transfer rate and oxidation current response toward isoprenaline (ISPT), a neurotransmitter drug. The hybrid composite when devised as an electrochemical sensor gives rise to a 7.9-fold higher oxidation current response to 0.65 μM ISPT than its pristine Co3O4 counterpart. The improved charge kinetics and generation of a superior oxidation current emphasized the critical role of Ti3C2T x as an interactive substrate in the Co3O4–MX hybrid. The analytical detection capability assessed via differential pulse voltammetry (DPV) confirmed the sensor’s high selectivity and marked stability both in low and high concentration ranges of ISPT ((0.01 to 0.33 μM) and 0.5 to 0.9 μM) with a limit of detection (LOD) of 3 × 10–3 μM (for low concentrations). Importantly, the fabricated sensor could detect ISPT from harsh biological environments such as human urine samples with a recovery rate of 99%. Moreover, the sensor exhibited a stable working response during its prolonged storage of 30 days in an aqueous PBS system. The proposed route of using MXenes as a conductive substrate paves the way for developing a robust metal-oxide-based redox-active hybrid system for the sensitive detection of important therapeutic compounds.

The aim was to have a three-dimensional evaluation of radiographic changes after indirect pulp capping (IPC) with silver diamine fluoride (SDF) with or without potassium iodide (KI) and resin modified glass ionomer cement (RMGIC) in deep carious young permanent molars using cone beam computed tomography (CBCT). 108 first permanent molars with deep occlusal cavitated caries lesions, in forty-nine 6–9-year-old children, were randomly allocated to one of 3 groups (n=36) and treated with SDF+KI, SDF and RMGIC as IPC materials. CBCT scans were taken at 0 and at 12-months to assess tertiary dentin formation (volume and grey level intensity), increase in root length, and pathological changes as secondary caries, periapical radiolucency, internal resorption and obliteration of the pulp. The three-dimensional image analysis procedures were performed using ITK-SNAP and 3D Slicer CMF. Comparisons were made using analysis of variance with a fixed effect for treatment and random effects for patient, and patient-by-treatment to account for within-patient correlations. A two-sided 5% significance level was used. There were no significant differences among the three groups regarding tertiary dentin volume (p=0.712) and grey level intensity (p=0.660), increase in root length (p=0.365), prevention of secondary caries (p=0.63) and periapical radiolucency (p=0.80) in the analysed 69 CBCT scans. The study did not find differences among the groups regarding quality and quantity of tertiary dentin formed, increase in root length, absence of secondary caries and other signs of failure as shown by CBCT. Clinical Significance: The results show no significant differences in radiographic outcomes (quality and quantity of tertiary dentin formed, increase in root length, absence of secondary caries and other signs of failure) when using SDF+KI, SDF and RMGIC in IPC. The results of this study can help guide treatment decision making regarding use of SDF and SDF+KI as IPC materials in deep cavitated lesions.

Objective: To assess and compare the transverse dental arch relationship and occlusion in surgically repaired unilateral cleft lip and palate Egyptian children with those of healthy comparable non-cleft children. Study design: Comparative cross-sectional. Thirty-one non-syndromic children with repaired unilateral cleft lip and palate (UCLP) and mean age 7.35 ± 1.52 years together with thirty-one healthy, comparable, non-cleft children were recruited from Faculty of dentistry, Alexandria University. For each subject, sagittal molar and cuspid occlusion were measured using dental study casts. The buccolingual dental arch relationships were determined using modified Huddart/ Bodenham scoring system. Results: Mesial step terminal plane and class III cuspid relation were significantly higher in UCLP children in the age group 4-5 years. Class III permanent molar and cuspid relations were significantly higher in UCLP children in both age groups 6-7 and 8-9 years. Modified Huddart/Bodenham showed a significantly more negative total arch constriction score in 6-9 year old UCLP children. Conclusions: There was a predilection for most of UCLP children to have mesial step terminal plane in primary dentition, class III permanent molar relation in mixed dentition and Class III cuspid relations. Modified Huddart/ Bodenham scores revealed that UCLP children suffered from constricted maxillary arch especially in the canine region.