Study of chemical reactivity and molecular interactions of the hydrochlorothiazide-4-aminobenzoic acid cocrystal using spectroscopic and quantum chemical approaches.

In this study, the molecular, electronic, and chemical properties of the drug hydrochlorothiazide (HCTZ) are determined after cocrystallization with 4-aminobenzoic acid (4-ABA). Analysis has been performed to understand how those variations lead to alteration of physical properties and chemical reactivity in the cocrystal HCTZ-4ABA. IR and Raman characterizations were performed along with quantum chemical calculations. A theoretical investigation of hydrogen bonding interactions in HCTZ-4ABA has been conducted using two functionals: B3LYP and wB97X-D. The results obtained by B3LYP and wB97X-D are compared which leads to the conclusion that B3LYP is the best applied function (density functional theory) to obtain suitable results for spectroscopy. The chemical reactivity descriptors are used to understand various aspects of pharmaceutical properties. Natural bond orbital (NBO) analysis and quantum theory of atoms (QTAIM) are used to analyze nature and strength of hydrogen bonding in HCTZ-4ABA. QTAIM analyzed moderate role of hydrogen bonding interactions in HCTZ-4ABA. The calculated HOMO-LUMO energy gap shows that HCTZ-4ABA is chemically more active than HCTZ drug. These chemical parameters suggest that HCTZ-4ABA is chemically more reactive and softer than HCTZ. The results of this study suggest that cocrystals can be a good alternative for enhancing physicochemical properties of a drug without altering its therapeutic properties.

Spectroscopic assessments on Sm3+ ions doped phospho-borate glasses mixed with fluoride modifiers for the applications of reddish-orange visible light.

Sm3+ions doped Phospho-Borate glasses were synthesized and their physical and spectroscopic parameters were studied to evaluate its potential reddish-orange emission for photonic applications. Structural investigation made through XRD analysis confirms the amorphous nature. The evaluated bonding parameters from the absorption spectral analysis confirm the ionic bonding of the Sm-O network in the prepared glasses. Four emission bands were observed from the luminescence spectra, and the HT 4G5/2 → 6H7/2 is observed at 601 nm. The oscillator strength values elucidate the intensity of the absorption bands, and the PBKZnF:Sm sample exhibits a higher oscillator strength value. The Judd-Ofelt intensity parameters were observed to trail the trend Ω4 > Ω6. > Ω2 for the majority of the samples. The CIE 1931 color chromaticity investigation confirms that the present glass samples are suitable for reddish-orange media. Barium and strontium-incorporated glasses exhibit outstanding lasing potential, which was confirmed through the efficiency of the quantum yield and some of the radiative parameters like effective bandwidth, transition probability and stimulated emission cross-section. Radiative parameters have been calculated from the luminescence spectra. Amid all transitions, 4G5/2 →6H7/2 transition has higher transition probability and higher stimulated emission cross-section values for all the prepared glass samples. Barium-incorporated glass exhibits a higher emission cross-section of 30.55 × 10-22 cm2 and a transition probability of 30.89 s-1 compared to all other glasses. The non-exponential decay profiles of the fabricated samples were plotted by examining the excitation wavelength at 402 nm and emission wavelength at 600 nm. Of all the prepared glasses, the quantum efficiency is found to be higher for the glass sample PBKSrF:Sm (65 %).

Effect of pH on the surface charges of permanently/variably charged soils and clay minerals.

Traditionally, the surface charge number (SCN) of permanently charged soils/clay minerals is believed to be unaffected by environmental pH. However, recent studies have revealed the occurrence of polarization-induced covalent bonding between H+ and the surface O atoms of permanently charged clay minerals. This discovery challenges the traditional notions of "permanently charged soil" and "permanently charged clay mineral". The purpose of this study is to confirm that there are no true "permanently charged clay" or "permanently charged soil". In this study, the SCNs of two permanently charged clay minerals, two variably charged clay minerals, five permanently charged soils (temperate soils), and four variably charged soils (tropical or subtropical soils) were measured at different pH values using the universal determination method of SCN. The results showed that: (1) The SCNs of the permanently/variably charged soils and clay minerals decreased significantly with decreasing pH; (2) the SCN of montmorillonite decreased less with decreasing pH than the SCNs of variably charged minerals, whereas the SCN of illite decreased to nearly the same extent, indicating strong polarization-induced covalent bonding between H+ and the surface O atoms of illite; (3) the SCNs of permanently charged soils decreased to a similar extent as those of variably charged soils with decreasing pH. This study demonstrated that the concepts, "permanently charged clay mineral" or "permanently charged soil", are questionable because of the polarization-induced covalent bonding between H+ and the surface O atoms of clay minerals.

Bis(amino acidato)copper(II) compounds in blood plasma: a review of computed structural properties and amino acid affinities for Cu2+ informing further pharmacological research.

Neutral bis(amino acidato)copper(II) [Cu(aa)2] coordination compounds are the physiological species of copper(II) amino acid compounds in blood plasma taking the form of bis(l-histidinato)copper(II) and mixed ternary copper(II)-l-histidine complexes, preferably with l-glutamine, l-threonine, l-asparagine, and l-cysteine. These amino acids have three functional groups that can bind metal ions: the common α-amino and carboxylate groups and a side-chain polar group. In Cu(aa)2, two coordinating groups per amino acid bind to copper(II) in-plane, while the third group can bind apically, which yields many possibilities for axial and planar bonds, that is, for bidentate and tridentate binding. So far, the experimental studies of physiological Cu(aa)2 compounds in solutions have not specified their complete geometries. This paper provides a brief review of my group's research on structural properties of physiological Cu(aa)2 calculated using the density functional theory (DFT) to locate low-energy conformers that can coexist in aqueous solutions. These DFT investigations have revealed high conformational flexibility of ternary Cu(aa)2 compounds for tridentate or bidentate chelation, which may explain copper(II) exchange reactions in the plasma and inform the development of small multifunctional copper(II)-binding drugs with several possible copper(II)-binding groups. Furthermore, our prediction of metal ion affinities for Cu2+ binding with amino-acid ligands in low-energy conformers with different coordination modes of five physiological Cu(aa)2 in aqueous solution supports the findings of their abundance in human plasma obtained with chemical speciation modelling.

2-Bromo-acetamide.

The title compound, C2H4BrNO, crystallizes in the monoclinic space group P21/c with one mol-ecule in the asymmetric unit. The almost planar mol-ecules are organized via N-H⋯O hydrogen bonds into a ladder-type network, which can be characterized by the graph sets R 2 2(8) and R 2 4(8). In addition, the mol-ecules are connected by C-H⋯O and C-H⋯Br contacts.

Bond Strength Evaluation of Ceramic Restorations with Immediate Dentin Sealing: A Systematic Review and Meta-Analysis.

Statement of the Problem: Immediate dentin sealing (IDS) was introduced to overcome the disadvantages of delayed dentin sealing like pollution of dentin tubules, microleakage, and bond strength destruction over time. The effect of IDS on the bond strength of indirect restorations is still debatable. Purpose: This study was conducted to determine the effect of IDS on the bond strength of ceramic restorations to dentin. Materials and Method: In this systematic review and meta-analysis, the study protocol was registered on the PROSPERO database under the registration number CRD420202014 27. MEDLINE (PubMed), Web of Science, Scopus, and ProQuest databases were searched until January 2021 and updated in January 2022. Worldcat.org and Opengrey.eu, ProQuest dissertation and thesis, and Google Scholar were searched to explore the grey literature. The in vitro studies evaluating the bond strength of ceramic restoration to dentin with and without IDS were included. Seven criteria were assessed to evaluate the risk of bias in the study. Statistical analyses were conducted using RevMan 5.3. The inverse variance method was used to determine the mean difference of micro-tensile bond strength (µTBS) and shear bond strength (SBS). Results: A total of 10 studies (20 datasets) were included in the meta-analysis. Regarding the µTBS analysis, IDS had a significantly higher bond strength than Delayed Dentin Sealing (DDS) (MD:1.16, 95%CI:0.28_2.03, I2=0%). However, no significant difference was found between them in the SBS analysis (MD:0.25, 95%CI: -0.56-1.06, I2=96%). All studies were categorized to have a moderate or high risk of bias. Conclusion: Most in vitro evidence showed favorable results for the effect of IDS on the bond strength and durability of indirect restorations. The adhesive system and the type of ceramic and its treatment before cementation are determining factors. Due to the heterogeneity of the outcomes and studies with a moderate/high risk of bias, the quality of the evidence was low.

Crystal structure and Hirshfeld surface analysis of (E)-N-(2-styrylphen-yl)benzene-sulfonamide.

The crystal structure of the title compound C20H17NO2S features hydrogen-bonding and C-H⋯π inter-actions. Hirshfeld surface analysis revealed that H⋯H, C⋯H/H⋯C and O⋯H/H⋯O inter-actions make a major contribution to the crystal packing. Docking studies were carried out to determine the binding affinity and inter-action profile of the title compound with EGFR kinase, a member of the ErbB family of receptor tyrosine kinases, which is crucial for processes such as cell proliferation and differentiation. The title compound shows a strong binding affinity with EGFR kinase, with the most favourable conformation having a binding energy of -8.27 kcal mol-1 and a predicted IC50 of 870.34 nM, indicating its potential as a promising candidate for targeted lung cancer therapy.

Synthesis, crystal structure and Hirshfeld surface analysis of sulfamethoxazolium methyl-sulfate monohydrate.

The mol-ecular salt sulfamethoxazolium {or 4-[(5-methyl-1,2-oxazol-3-yl)sulf-amo-yl]anilinium methyl sulfate monohydrate}, C10H12N3O3S+·CH3O4S-·H2O, was prepared by the reaction of sulfamethoxazole and H2SO4 in methanol and crystallized from methanol-ether-water. Protonation takes place at the nitro-gen atom of the primary amino group. In the crystal, N-H⋯O hydrogen bonds (water and methyl-sulfate anion) and inter-molecular N-H⋯N inter-actions involving the sulfonamide and isoxazole nitro-gen atoms, link the components into a tri-dimensional network, additional cohesion being provided by face-to-face π-π inter-actions between the phenyl rings of adjacent mol-ecules. A Hirshfeld surface analysis was used to verify the contributions of the different inter-molecular inter-actions, showing that the three most important contributions for the crystal packing are from H⋯O (54.1%), H⋯H (29.2%) and H⋯N (5.0%) inter-actions.

Coupling between 2-pyridyl-selenyl chloride and phenyl-seleno-cyanate: synthesis, crystal structure and non-covalent inter-actions.

A new pyridine-fused seleno-diazo-lium salt, 3-(phenyl-selan-yl)[1,2,4]selena-diazolo[4,5-a]pyridin-4-ylium chloride di-chloro-methane 0.352-solvate, C12H9N2Se2 +·Cl-·0.352CH2Cl2, was obtained from the reaction between 2-pyridyl-selenenyl chloride and phenyl-seleno-cyanate. Single-crystal structural analysis revealed the presence of C-H⋯N, C-H⋯Cl-, C-H⋯Se hydrogen bonds as well as chalcogen-chalcogen (Se⋯Se) and chalcogen-halogen (Se⋯Cl-) inter-actions. Non-covalent inter-actions were explored by DFT calculations followed by topological analysis of the electron density distribution (QTAIM analysis). The structure consists of pairs of seleno-diazo-lium moieties arranged in a head-to-tail fashion surrounding disordered di-chloro-methane mol-ecules. The assemblies are connected by C-H⋯Cl- and C-H⋯N hydrogen bonds, forming layers, which stack along the c-axis direction connected by bifurcated Se⋯Cl-⋯H-C inter-actions.

Influence of diode laser irradiation on microtensile bond strength of etch-and-rinse adhesive to dentin using two different etchants: An in vitro study.

Aim: The aim of this study was to evaluate the influence of 970 nm diode laser (DL) irradiation on the microtensile bond strength (µTBS) of etch-and-rinse adhesive (ERA) to dentin using phosphoric acid (PA) or alpha-hydroxy glycolic acid (GA) as etchants. Materials and Methods: A total of 32 human third molars were selected and assigned randomly among two different groups and four subgroups based on etching protocols and DL irradiation: PA, PA-DL, GA, and GA-DL. After tooth preparation and subsequent incremental composite build-up, the samples were stored in distilled water for 24 h at 37°C. µTBS values were obtained using the universal testing machine. The failure modes observed in dentin were categorized as adhesive, cohesive within dentin/resin, or mixed. Statistical Analysis: The data were analyzed using one-way analysis of variance, followed by Tukey's post hoc test (P ≤ 0.001). Results: GA showed better or similar bond strength values to PA. Furthermore, irradiation of DL increased the µTBS to dentin when both PA or GA are used as etchants. Conclusion: GA can be used as an alternative etchant to PA. DL irradiation stands as a promising approach for elevating the performance of ERA adhesive systems to dentin.

The association of delivery during a war with the risk for postpartum depression, anxiety and impaired maternal-infant bonding, a prospective cohort study.

OBJECTIVE: To examine the impact of war conditions on maternal mental health postpartum outcomes, specifically depression and anxiety, as well as on maternal-infant bonding (MIB). STUDY DESIGN: A prospective cohort study was performed on women who gave birth in a tertiary medical center during (October-November 2023) and before (March-May 2020) the Israel-Hamas War. All participants completed validated self-reported questionnaires: The Edinburgh Postnatal Depression Scale (EPDS ≥ 10), State-Trait Anxiety Inventory (STAI > 39) and the Postpartum Bonding Questionnaire (PBQ ≥ 26). RESULTS: A total of 502 women were included in the study, with 230 delivering during the war and 272 delivered before. The rates of postpartum depression (PPD) were higher in women delivering during the war (26.6% vs. 12.4%, p < 0.001), while multivariable regression revealing a two-fold higher risk (adjusted OR 2.35, 95% CI 1.16-4.74, p = 0.017). The rate of postpartum anxiety (PPA) risk was also higher (34.3% vs 17.0%, p < 0.001), reaching a trend towards significance when accounting for other risk factors (adjusted OR 2.06, 95% CI 0.97-4.36, p = 0.058). Additionally, delivery during the war was associated with specific factors of impaired maternal-infant bonding (MIB), although it did not increase the overall impaired MIB (PBQ ≥ 26) (10.2 ± 14.1 vs 8.3 ± 6.9, p = 0.075). CONCLUSION: The study revealed an increased risk of PPD, a marginally risk for PPA, and some aspects of impaired MIB among women delivering during the war. Maternal mental illness in the postpartum period has negative impacts on the entire family. Therefore, comprehensive screening and adequate resources should be provided for women delivering in war-conflict zones.

Constructing Molecular Networks on Metal Surfaces through Tellurium-Based Chalcogen-Organic Interaction.

On-surface molecular self-assembly presents an important approach to the development of low-dimensional functional nanostructures and nanomaterials. Traditional strategies primarily exploit hydrogen bonding or metal coordination, yet the potential of chalcogen bonding (ChB) for on-surface self-assemblies remains underexplored. Here, we explore fabricating molecular networks via tellurium (Te)-directed chalcogen-organic interactions. Employing carbonitrile molecules as molecular building blocks, we have achieved extended 2D networks exhibiting a 4-fold binding motif on Au(111), marking a notable difference from the conventional coordinative interaction involving transition metals. Our findings, supported by density functional theory (DFT) and scanning tunneling spectroscopy (STS), show that the Te-carbonitrile interaction exhibits lower stability compared to the metal-organic coordination, and the construction of the Te-directed molecular networks does not alter the electronic properties of the involved molecules. Introducing chalcogen-directed interactions may expand the spectrum of strategies in supramolecular assembly, contributing to the design of advanced molecular architectures for nanotechnological applications.

Phonon-Lithium Ion Interactions: A Case Study of LiM(SeO3)2 (M = Al, Ga, In, Sc, Y, and La).

Li ion diffusion is fundamentally a thermally activated ion hopping process. Recently, soft lattice, anharmonic phonon, and paddlewheel mechanism have been proposed to potentially benefit the ion transport, while the understanding of vibrational couplings of mobile ions and anions is still very limited but essential. Herein, we accessed the ionic conductivity, stability, and especially, lattice dynamics in LiM(SeO3)2 (M = Al, Ga, In, Sc, Y, and La) with two different types of oxygen anions within a LiO4 polyhedron, namely, edge-shared and corner-shared with MO6 polyhedra, the prototype of which, LiGa(SeO3)2, has been theoretically reported before with the similar structural features to NASICON and later experimentally synthesized with the room temperature conductivity ∼0.11 mS cm-1. It is interesting to note that LiM(SeO3)2 with a higher Li phonon band center shows higher Li conductivity, which is in contradiction to the conventional understanding of the importance for soft lattice to superionic conductors. The anharmonic and harmonic phonon interactions as well as the couplings between the vibration of the edge-bonded or corner-bonded anion in Li polyanions and the Li ion diffusion have been studied in detail. With transition metal M changing from La, Y, In, Ga, Al, and Sc, anharmonic phonons increase with reduced activation energy for Li diffusion. The phonon modes dominated by the edge-bonded oxygen anions contribute more to the migration of the Li ion than those dominated by the corner-bonded oxygen anions because of the greater atomic interaction between the Li ion and the edge-bonded anions. Thus, rather than the overall lattice softness, attention shall be given to reduce the frequency of the critical phonons contributing to Li ion diffusion as well as to increase the anharmonicity, i.e., through asymmetric Li polyhedra, for the design of Li ion superionic conductors for all-solid-state batteries.

Chalcogen bonds enable efficient photoreduction of sulfur-containing heterocycles.

Chalcogen bonding interactions have attracted significant attention in a broad chemistry community, with a particular focus on their ability to stabilise the key transition states in various organic synthetic routes. In this work, we demonstrate that they can also be harnessed in selective photoredox reactions, which cannot be otherwise achieved with alternative approaches to photoreduction. We demonstrate this concept through the photoreduction of the sulfur-containing DNA nucleoside precursor thioanhydrouridine to 2'-deoxy-thiouridine, revealing the previously unrecognized role of bisulfide in this process. Based on quantum chemical simulations, we identify a stable chalcogen-bonding complex of the hydrosulfide anion and thionhydrouridine (HS-…S contacts), which enables directional photoinduced electron transfer, resulting in the formation of non-canonical DNA nucleoside. We also disprove the possibility that photoreduction of thioanhydronucleosides could be initiated by hydrated electrons generated from irradiated bisulfide anions which do not interact with the chromophore. Finally, we show that selective photoreduction mediated by chalcogen bonds can only occur for chromophores, which exhibit sufficiently long excited-state lifetimes in the locally-excited states to undergo transition to the productive charge transfer state. These findings can be further used in the design of similar photoredox reactions which can employ the potential of chalcogen bonding interactions.

Comparison of bond failure with resin-modified glass ionomer cement and visible light-cured composite bonding systems in orthodontic patients: A split-mouth randomized controlled trial.

BACKGROUND: Resin-modified glass ionomer cement (RMGIC) is considered a fluoride-releasing bonding agent. OBJECTIVES: The aim of the study was to evaluate the rate of bracket bond failure with light-cured composite (LCC) and RMGIC, and to evaluate factors that contribute to the rate of bracket failure with both bonding agents. MATERIAL AND METHODS: A randomized controlled trial was conducted on a sample size of 33 patients. The patients were randomly allocated for bonding with visible LCC (control group) or RMGIC (intervention group) using the lottery method. The study was double-blinded. The rate of bracket bond failure was assessed after a follow-up of minimum 3 months and evaluated using the survival regression analysis, taking into account the effects of bonding agents and other factors influencing bracket bond failure. RESULTS: A total of 33 participants were recruited for the study, and 66 quadrants for the intervention and control groups were randomly selected and analyzed. The data was normally distributed and the mean age of the subjects was comparable between both bonding systems. The results of the regression analysis indicated that there was no statistically significant difference between the rate of bracket bond failure with RMGIC and LCC (p = 0.081). However, after analyzing the mean days of survival, it was found that bracket survival was negligibly low with RMGIC, with a mean of 216.00 ±133.72 days as compared to LCC, with a mean survival of 224.11 ±124.59 days. No adverse effects were observed during the course of the trial. CONCLUSIONS: There was no difference in the rate of bracket bond failure between the intervention and control groups. The survival rate of brackets treated with RMGIC was found to be comparable to that of LCC, with a minimal difference.

Surface Optimization of Noble-Metal-Free Conductive [Mn1/4Co1/2Ni1/4]O2 Nanosheets for Boosting Their Efficacy as Hybridization Matrices.

Conductive 2D nanosheets have evoked tremendous scientific efforts because of their high efficiency as hybridization matrices for improving diverse functionalities of nanostructured materials. To address the problems posed by previously reported conductive nanosheets like poorly-interacting graphene and cost-ineffective RuO2 nanosheets, economically feasible noble-metal-free conductive [MnxCo1-2xNix]O2 oxide nanosheets are synthesized with outstanding interfacial interaction capability. The surface-optimized [Mn1/4Co1/2Ni1/4]O2 nanosheets outperformed RuO2/graphene nanosheets as hybridization matrices in exploring high-performance visible-light-active (λ >420 nm) photocatalysts. The most efficient g-C3N4-[Mn1/4Co1/2Ni1/4]O2 nanohybrid exhibited unusually high photocatalytic activity (NH4 + formation rate: 1.2 mmol g-1 h-1), i.e., one of the highest N2 reduction efficiencies. The outstanding hybridization effect of the defective [Mn1/4Co1/2Ni1/4]O2 nanosheets is attributed to the optimization of surface bonding character and electronic structure, allowing for improved interfacial coordination bonding with g-C3N4 at the defect sites. Results from spectroscopic measurements and theoretical calculations reveal that hybridization helps optimize the bandgap energy, and improves charge separation, N2 adsorptivity, and surface reactivity. The universality of the [Mn1/4Co1/2Ni1/4]O2 nanosheet as versatile hybridization matrices is corroborated by the improvement in the electrocatalytic activity of hybridized Co-Fe-LDH as well as the photocatalytic hydrogen production ability of hybridized CdS.

Structural Snapshots, Trajectory and Thermodynamics of the Reversible µ-1,2-Peroxo/µ-1,1-Hydroperoxo Dicopper(II) Interconversion.

Hydrogen bonds involving the oxygen atoms of intermediates that result from copper-mediated O2 activation play a key role for controlling the reactivity of Cux/O2 active sites in metalloenzymes and synthetic model complexes. However, structural insight into H-bonding in such transient species as well as thermodynamic information about proton transfer to or from the O2-derived ligands is scarce. Here we present a detailed study of the reversible interconversion of a µ1,2-peroxodicopper(II) complex ([1]+) and its µ1,1-hydroperoxo congener ([2]+) via (de)protonation, including the isolation and structural characterization of several H-bond donor (HBD) adducts of [1]+ and the determination of binding constants. For one of these adducts a temperature-dependent µ1,2-peroxo/µ1,1-hydroperoxo equilibrium associated with reversible H+-translocation is observed, its thermodynamics investigated experimentally and computationally, and effects of H-bonding on spectroscopic parameters of the CuII2(µ1,2-O2) species are revealed. DFT calculations allowed to fully map and correlate the trajectories of H+-transfer and µ1,2-peroxo→µ1,1-peroxo rearrangement. These findings enhance our understanding of two key intermediates in bioinspired Cu2/O2 chemistry.

Is bracket bonding with guided bonding devices accurate enough for crowded dentition?

BACKGROUND: This research aimed to study whether bracket bonding using guided bonding devices (GBDs) is accurate enough for crowded dentitions in vitro. METHODS: Fifteen three-dimensionally (3D) printed resin model sets were included and divided into three groups: mild, moderate, and severe crowding. The resin models were scanned and virtually bonded with brackets. Corresponding GBDs were generated and 3D printed. Subsequently, the brackets were bonded to the resin models on a dental mannequin using the GBDs. The models with bonded brackets were scanned, and comparisons were made between the positions of the actually bonded and the planned ones to evaluate possible deviations. RESULTS: There was no immediate bonding failure in any group. The bonding duration tended to increase with crowding severity (P > 0.05). Almost all linear and angular deviations in all groups were below 0.5 mm and 2°, respectively, and no statistically significant difference was found among the different crowding degrees (P > 0.05). In all groups, the brackets tended to deviate lingually and had buccal crown torque. Brackets in the groups with mild and severe crowding showed a tendency for mesiobuccal rotation. CONCLUSION: GBDs provide high bracket bonding accuracy for dentitions with different crowding degrees and, thus, could hopefully be applied to uncrowded and crowded dentitions alike.

Comprehensive clinical evaluation of indirect and direct bonding techniques in orthodontic treatment: a single-centre, open-label, quasi-randomized controlled clinical trial.

BACKGROUND: Few prospective investigations have compared direct and indirect techniques through comprehensive and detailed clinical evaluations, considering the impact of all factors. OBJECTIVES: This study aimed to compare and evaluate direct and indirect bonding methods at a single institution and to clarify the selection criteria for the bonding method. MATERIALS AND METHODS: This single-centre, quasi-randomized controlled clinical trial included 153 patients who required fixed orthodontic treatment. They were randomly divided into indirect and direct binding groups by the project lead (K.K.), who was blinded to all clinical data, and performed the allocation using medical record numbers. The chair time for bracket bonding, discomfort during bracket bonding, oral hygiene after bonding, number of bracket failures, number of intentional bracket reattachments, post-treatment occlusal index, and total treatment time were assessed. Outcomes were compared using a two-sample t-test or Mann-Whitney U test (P < .05). RESULTS: Fifty-eight patients were included in the indirect bonding group (20 male, 38 female; mean age: 20.63 ±â€…5.69 years) and 66 (14 male, 52 female; mean age: 23.17 ±â€…8.83 years) in the direct bonding group. Compared to the direct bonding group, the indirect bonding group had shorter chair time (P < .001), a shorter total treatment period (P < .01), and a better final occlusal relationship (P < .001). The number of bracket detachments was higher (P < .001) in the indirect bonding group, but the number of intentional reattachments was lower (P < .001). CONCLUSION: Indirect bonding may improve the efficiency of orthodontic treatment. HARMS: No harm was observed during the study. TRIAL REGISTRATION NUMBER: This trial was approved by the Ethics Review Committee of Okayama University (approval number: d10001), UMIN registration number 000022182.

Synergistic effects of bacteria, enzymes, and cyclic mechanical stresses on the bond strength of composite restorations.

Predicting how tooth and dental material bonds perform in the mouth requires a deep understanding of degrading factors. Yet, this understanding is incomplete, leading to significant uncertainties in designing and evaluating new dental adhesives. The durability of dental bonding interfaces in the oral microenvironment is compromised by bacterial acids, salivary enzymes, and masticatory fatigue. These factors degrade the bond between dental resins and tooth surfaces, making the strength of these bonds difficult to predict. Traditionally studied separately, a combined kinetic analysis of these interactions could enhance our understanding and improvement of dental adhesive durability. To address this issue, we developed and validated an original model to evaluate the bond strength of dental restorations using realistic environments that consider the different mechanical, chemical, and biological degradative challenges working simultaneously: bacteria, salivary esterases, and cyclic loading. We herein describe a comprehensive investigation on dissociating the factors that degrade the bond strength of dental restorations. Our results showed that cariogenic bacteria are the number one factor contributing to the degradation of the bonded interface, followed by cyclic loading and salivary esterases. When tested in combinatorial mode, negative and positive synergies towards the degradation of the interface were observed. Masticatory loads (i.e., cycling loading) enhanced the lactic acid bacterial production and the area occupied by the biofilm at the bonding interface, resulting in more damage at the interface and a reduction of 73 % in bond strength compared to no-degraded samples. Salivary enzymes also produced bond degradation caused by changes in the chemical composition of the resin/adhesive. However, the degradation rates are slowed compared to the bacteria and cyclic loading. These results demonstrate that our synergetic model could guide the design of new dental adhesives for biological applications without laborious trial-and-error experimentation.