A novel cutting machine supports dental students to study the histology of the tooth hard tissue.

Background/purpose: Ground section is the only way to study tooth enamel, and the conventional methods of making ground sections, grinding by hand or using a hard tissue microtome are either too time consuming or money costing. This study aimed to develop and assess a novel cutting machine in making ground sections and learning aid for dental students.

Materials And Methods: By using the novel cutting machine, the students cut the embedding teeth and got 50 μm ground sections efficiently.

Novel Calcium Phosphate Cement with Metformin-Loaded Chitosan for Odontogenic Differentiation of Human Dental Pulp Cells.

Metformin is an old and widely accepted first-line drug for treating type 2 diabetes. Our previous studies demonstrate that metformin can stimulate the osteo/odontogenic differentiation of human-induced pluripotent stem cell-derived mesenchymal stem cells and human dental pulp cells (DPCs). Due to the rapid dilution of metformin from the defect area, the aim of this study was to develop a drug delivery system with controlled release of metformin to promote cell viability and odontogenic differentiation of DPCs favoring dentin regeneration.

Theoretical Insights into Imidazolidine Oxidation of Imidacloprid by Cytochrome P450 3A4.

The metabolic mechanisms for imidazolidine oxidation of imidacloprid (IMI) by cytochrome P450 3A4 (CYP3A4) have been investigated using quantum mechanical/molecular mechanical (QM/MM) calculations. The binding mode of CYP3A4 with IMI is examined by molecular docking in collaboration with molecular dynamics (MD) simulations. The results show that there are six amino acid residues, involving Arg192, Phe195, Ile349, Ala285, Phe284 and Phe88, closely distributed around the IMI.

Alcohol Inhibits Odontogenic Differentiation of Human Dental Pulp Cells by Activating mTOR Signaling.

Long-term heavy alcohol consumption could result in a range of health, social, and behavioral problems. People who abuse alcohol are at high risks of seriously having osteopenia, periodontal disease, and compromised oral health. However, the role of ethanol (EtOH) in the biological functions of human dental pulp cells (DPCs) is unknown.

Physical and chemical properties of an antimicrobial Bis-GMA free dental resin with quaternary ammonium dimethacrylate monomer.

The objective of this study was to evaluate the antibacterial activity, physicochemical properties of the quaternary ammonium dimethacrylate monomer N,N-bis[2-(3-(methacryloyloxy)propanamido)-ethyl]-N-methylhexadecyl ammonium bromide (IMQ-16) containing diurethane dimethacrylate (UDMA)/tricyclodecane dimethanol diacrylate (SR833s) resin system and compare with bisphenylglycidyl dimethacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) resin system. It was hypothesized that the physical and chemical properties of the experimental polymers would be comparable with Bis-GMA/TEGDMA polymer and IMQ-16 monomer could endow the UDMA/SR833s resin with antibacterial activity. Double bond conversion (DC) was measured using Fourier transform infrared spectroscopy (FTIR).

Two-year clinical evaluation of composite resins in non-carious cervical lesions.

Objective: The purpose of this double-blind, randomised trial was to compare the clinical performance of a hybrid composite (Clearfil AP-X, Kuraray, Tokyo) and a nanocomposite (Filtek Z350, 3M ESPE, St. Paul, MN) over a period of 2 years in non-carious class V lesions using a modified US Public Health Service (USPHS) system.

Methods: Forty-six patients with at least one pair of equivalent non-carious cervical lesions under occlusion and a mean age of 44.

[Effects of muramyl dipeptide on the differentiation of human dental pulp cells].

Objective: To investigate the nucleotide-binding oligomerization domain-2 (NOD-2) gene expression in deep caries and the effects of NOD-2 agonist muramyl dipeptide (MDP) on the differentiation of human dental pulp cells (hDPC).

Methods: NOD-2 gene level in deep caries and healthy pulp tissue was determined by real-time quantitative polymerase chain reaction (realtime-PCR). Realtime-PCR, Western blotting and immunofluorescence were performed to evaluate NOD-2 gene and protein expression.

[Application and prospect on the resin-dentin adhesion in the root canal therapy].

The application of adhesive root canal filling materials is the tendency in root canal obturation. The orientation is to develop the adhesive core material and sealer making a whole structure. In this review, we summarized the researches on the resin-dentin adhesion in the root canal obturation.

[Clinical observation on the characteristics of occlusion and tooth abrasion in patients with cracked tooth].

Objectives: To investigate the occlusal characteristics and the condition of tooth abrasion in patients with cracked tooth and to discuss the etiology of the cracked tooth and the relationships between occlusal disorder, tooth abrasion and cracked tooth.

Methods: Twenty-seven patients with cracked tooth were selected. The occlusal courses were recorded by T-ScanIII system in intercuspal position, protrusive movement and lateral movement.

Expression of nucleotide-binding oligomerization domain 2 in normal human dental pulp cells and dental pulp tissues.

Introduction: The nucleotide-binding oligomerization domain (NOD) proteins belong to a distinct family of proteins that are implicated in the intracellular recognition of bacterial components. NOD2 appears to be a sensor of bacterial peptidoglycans because it recognizes a minimal motif present in all peptidoglycans. The interaction of NOD2 with downstream signaling molecules ultimately results in the activation of NF-kappaB and production of inflammatory mediators in innate immunity.

[Morphological characteristics of the mandibular first premolars in people from Pearl River Delta region in Guangdong province].

Objective: To investigate the morphological characteristics of the mandibular first premolars in people from Pearl River Delta region in Guangdong province using three techniques, including periapical radiographs, the radiographs with files inserted the canals and the clearing technique.

Methods: A total of 363 extracted mandibular first premolars were collected and numbered. Two preoperative radiographs were taken in buccolingual and mesiodistal directions respectively.

Synthesis and characterization of dimethacrylate monomer with high molecular weight for root canal filling materials.

A new dimethacrylate monomer 9,9'-bis[4-(2'-hydroxy-3'-methacryloyloxy-propoxy)phenyl] fluorene (3) with a molecular weight of 634 was synthesized in 51.4% yield by addition of a glycidyl ether group to 9,9'-bis(4-hydroxyphenyl) fluorene (1) by the reaction of compound 1 with epichlorohydrin, and then introducing the methacrylate moiety by the reaction of the epoxy group with methacrylic acid. The structure of monomer 3 was confirmed by FT-IR, (1)H-NMR, mass spectra and elemental analysis.

[Comparative study of sealing ability and fracture resistance of roots endodontically treated with bonded and unbonded filling materials].

Objective: To compare the sealing ability and fracture resistance of roots endodontically treated with bonded and unbonded filling materials.

Methods: One hundred and fifteen straight mandibular premolar teeth with single canal were divided randomly into 6 experimental groups, with 15 samples each, and 3 control groups. The sealing ability was evaluated using a glucose quantitative microleakage mode and fracture resistance was tested by universal testing machine.

An evaluation of the sealing ability of a polycaprolactone-based root canal filling material (Resilon) after retreatment.

Objective: The aim of this study was to evaluate the sealing ability of Resilon after retreatment.

Study Design: Sixty-six single-rooted mandibular premolars were enlarged to apical size 45 and then obturated with Resilon. The roots were randomly divided into 3 groups (n = 22/group).

Adenovirus-mediated recombinant human bone morphogenetic protein-7 expression promotes differentiation of human dental pulp cells.

Recombinant human bone morphogenetic protein-7 (BMP-7) has been shown to stimulate new reparative dentin formation in animal models. However, little is known about whether BMP-7 could promote the odontoblast-like differentiation and the formation of mineralized nodules in human dental pulp cells. Here, we reported that the infection with adenovirus-BMP-7 (Ad-BMP-7), a BMP-7-expressing adenoviral vector, induced the expression of BMP-7 in primarily cultured human dental pulp cells in the long term with little effect on their proliferation and viability.

[Preparation and stability assessment of a new resin root canal filling material].

Objective: To synthesize a new resin root canal filling material (NRCFM) and evaluate its stability in water and artificial saliva.

Methods: The new root canal filling material was made of thermoplastic elastomer (TPE), ethylene vinyl acetate (EVA) and activity fillers. The NRCFM's stability in water and artificial saliva with different pH values was assessed using gravimetric analysis, ICP and FE-SEM.

[Effects of adenovirus-mediated human bone morphogenetic protein-7 on proliferation and differentiation of human dental pulp cells].

Objective: To investigate the effect of adenovirus expressing human bone morphogenetic protein-7 (hBMP-7) on proliferation and differentiation of human dental pulp cells.

Methods: The replication-deficient adenoviral vector encoding hBMP-7 gene was constructed by using homologous recombinant modality. The efficiency of transfection was evaluated by fluorescent microscopy and flow cytometry.