Experts consensus on the procedure of dental operative microscope in endodontics and operative dentistry.

The dental operative microscope has been widely employed in the field of dentistry, particularly in endodontics and operative dentistry, resulting in significant advancements in the effectiveness of root canal therapy, endodontic surgery, and dental restoration. However, the improper use of this microscope continues to be common in clinical settings, primarily due to operators' insufficient understanding and proficiency in both the features and established operating procedures of this equipment. In October 2019, Professor Jingping Liang, Vice Chairman of the Society of Cariology and Endodontology, Chinese Stomatological Association, organized a consensus meeting with Chinese experts in endodontics and operative dentistry. The objective of this meeting was to establish a standard operation procedure for the dental operative microscope. Subsequently, a consensus was reached and officially issued. Over the span of about four years, the content of this consensus has been further developed and improved through practical experience.

Decreased expression of microRNA-30b promotes the development of pulpitis by upregulating the expression of interleukin-6 receptor.

The present study aimed to examine the expression of interleukin-6 receptor (IL-6R) mRNA and protein in pulp tissues, blood and saliva from patients with pulpitis. It also investigated the association between IL-6R and microRNA (miR)-30b, as well as their effects on pulpitis. A total of 28 patients with pulpitis were recruited into the experimental group and 16 subjects with no pulpitis who also underwent tooth extraction were recruited into the control group. Pulp tissues, plasma and saliva were collected from all participants. Reverse transcription-quantitative polymerase chain reaction was used to determine the expression of IL-6R mRNA and miR-30b in all sample types. Western blot analysis was performed to examine the protein expression of IL-6R in pulp tissues, while ELISA was used to determine the contents of IL-6R protein in the plasma and saliva samples. A dual luciferase reporter assay was performed to verify the interactions between IL-6R and miR-30b. The expression of IL-6R mRNA in the pulp tissues, plasma and saliva was significantly increased in patients with pulpitis compared with the control group. Similarly, the IL-6R protein expression in the samples from patients with pulpitis were also significantly increased compared with the control group. Conversely, the expression of miR-30b was significantly reduced in the samples from patients with pulpitis compared with the control group. The dual luciferase reporter assay revealed that miR-30b may bind with the 3'-untranslated seed region of IL-6R mRNA to regulate its expression. The present study demonstrated that the upregulated expression of IL-6R in pulp tissues, plasma and saliva from patients with pulpitis was associated with the downregulation of miR-30b expression. In addition, miR-30b may affect the progression of pulpitis via IL-6R and may be a potential genetic marker for the diagnosis of pulpitis.

Facile Preparation of Nanosilver Particles with Excellent Antimicrobial Activity via Release of Ionic Silver.

Nanosilver particles (SNPs) have been widely exploited in various fields, including the medical sciences due to their excellent inhibitory and bactericidal effects. It is of great importance to prepare SNPs using green synthesis that has environmentally acceptable solvent systems and eco-friendly reducing agents. In the current study, gallic acid was employed as both a reducing agent and a stabilizing agent to synthesize SNPs at mild ambient conditions. The image of transmission electron microscopy (TEM) showed that SNPs exhibited approximately spherical shape with the average diameter of 13.81±2.21 nm. The absorbance peak of obtained SNPs was sharp with the maximum wavelength of 400.5 nm by ultraviolet-visible (UV-vis) spectroscopy, suggesting the formation of small and highly monodispersed SNPs. The antimicrobial potential of the SNPs was evaluated against multiple common pathogenic microbes. The results indicated that the microbial sensitivity to the SNPs was found to vary depending on the microbial species. Among them, the gram-negative bacteria exhibited more sensitive toward SNPs than the gram-positive bacteria. In addition, the N-acetyl-L-cysteine (NAC), a silver ion chelator, pretreatment could protect the E. coli and P. aeruginosa from the SNPs inhibition, while the pretreatment of the L-ascorbic acid, an antioxidant against oxidative stress, did not significantly influence the antibacterial effects of the SNPs. These data suggested that the ionic silver release, but not reactive oxygen species (ROS), played a key role in the antimicrobial effect of the SNPs. To sum up, this study provides an environmentally friendly technique for facile synthesis of SNPs with excellent antibacterial potential.

[Comparative study of root canal morphology of mandibular incisors by cone-beam CT and canal staining and clearing technique].

PURPOSE: To compare the root canal morphology of mandibular incisors by using cone-beam CT (CBCT) and canal staining and clearing technique. METHODS: Sixty-one extracted mandibular incisors with complete dental root and apex which received no endodontic treatment and no post crown restoration were selected. Each tooth was radiographed with CBCT, and the root canal system was stained by canal staining and clearing technique. The consistency of the number of root canal, root canal Vertucci type of mandibular permanent incisors between the two methods were compared, and the differences of the detection rate on root canal branch structure between the two methods were analyzed. The results were statistically analyzed with SPSS 17.0 software package. RESULTS: The Kappa value of single and double root canal types between CBCT and canal staining and clearing technique was 0.847 (P<0.001). The Kappa value of Vertucci root canal types between CBCT and canal staining and clearing technique was 0.861 (P<0.001). The detection rates of root canal branch structure were 8.19% and 22.95%, respectively, with significant difference between the two methods (P=0.025). The canal staining and clearing technique was significantly better than CBCT in detection of root canal branch structure. CONCLUSIONS: CBCT can reflect the root canal types nearly perfectly, but inferior to canal staining and clearing technique in detection of root canal branch structure, CBCT is a relatively accurate clinical diagnosis tool of root canal morphology.

Noninvasive Assessment of Early Dental Lesion Using a Dual-Contrast Photoacoustic Tomography.

Dental hard tissue lesions, including caries, cracked-tooth, etc., are the most prevalent diseases of people worldwide. Dental lesions and correlative diseases greatly decrease the life quality of patients throughout their lifetime. It is still hard to noninvasively detect these dental lesions in their early stages. Photoacoustic imaging is an emerging hybrid technology combining the high spatial resolution of ultrasound in deep tissue with the rich optical contrasts. In this study, a dual-contrast photoacoustic tomography is applied to detect the early dental lesions. One contrast, named B-mode, is related to the optical absorption. It is good at providing the sharp image about the morphological and macro-structural features of the teeth. Another contrast, named S-mode, is associated with the micro-structural and mechanical properties of the hard tissue. It is sensitive to the change of tissue properties induced by the early dental lesions. Experiments show that the comprehensive analysis of dual-contrast information can provide reliable information of the early dental lesions. Moreover, the imaging parameter of S-mode is device-independent and it could measure tissue properties quantitatively. We expect that the proposed scheme could be beneficial for improving safety, accuracy and sensitivity of the clinical diagnosis of the dental lesion.

Anti-inflammatory effects of luteolin on experimental autoimmune thyroiditis in mice.

Hashimoto's thyroiditis (HT) is the most common organ-specific autoimmune disease and is believed to be a predominately T cell-mediated autoimmunity. Signal transducer and activator of transcription (STAT)3 is a crucial transcription factor of T cell-mediated immunity, with key roles in the proliferation and migration of T helper (Th) cells, differentiation of Th cells into Th17 cells, and the balance between Treg cells and Th17 cells. Flavonoid luteolin has been shown to markedly inhibit Tyr705 activation/phosphorylation of STAT3 and exert anti-inflammatory effects in multiple sclerosis. In the present study, the effect of luteolin on experimental autoimmune thyroiditis (EAT) was analyzed in C57BL/6 mice. Hematoxylin and eosin examination showed that luteolin attenuated lymphocytic infiltration and follicle destruction in thyroid glands. Immunohistochemistry results demonstrated that luteolin significantly reduced the phosphorylation of STAT3 within the thyroid. An in vitro study was carried out in a RAW264.7 macrophage cell line. Western blot findings demonstrated that luteolin significantly inhibited interferon-γ-induced increases in cyclooxygenase 2, phosphorylated STAT1 and phosphorylated STAT3 expression levels and the secretion of the proinflammatory cytokine tumor necrosis factor-α in supernatants. The present findings indicated that luteolin may exert potent anti-inflammatory effects on murine EAT, which may provide a novel therapeutic medication strategy for the early intervention of HT.

Analysis of Mtwo rotary instrument separation during endodontic therapy: a retrospective clinical study.

To analyze the incidence of instrument separation (IS) and the factors influencing it, when associated with Mtwo rotary system (VDW, Munich, Germany) during endodontic therapy. A retrospective study involving a total of 24,108 root canals (11,036 endodontic treated teeth) was conducted at Nanjing Stomatology Hospital between January 2011 and March 2013. The information included were tooth type, root canal curvature, number of fractured instruments, length of the separated fragments, and the distance from broken tip to apex. The incidence of IS was observed to be 2.2 % according to the number of teeth and 1.0 % according to the number of root canals. Many of the separated fragments were 2-4 mm in length and the mean length was 3.07 ± 1.46 mm, and 78.4 % of fractures occurred in the apex. The mean length of separated fragments in severely curved canals was maximum, while ultra-severe curved canals was observed to be minimum. Mtwo instruments demonstrated an extremely low fracture rate during endodontic therapy. Molar teeth (especially lower molars) and the degree of canal curvature had a significant effect on the incidence of IS.

Antitumor effect of TRAIL on oral squamous cell carcinoma using magnetic nanoparticle-mediated gene expression.

We developed a new magnetic nanovector to improve the efficiency and targeting of transgene therapy for oral squamous cell carcinoma (OSCC). Positively charged polymer PEI-modified Fe(3)O(4) magnetic nanoparticles were tested as gene transfer vectors in the presence of a magnetic field. The Fe(3)O(4) nanoparticles were prepared by a co-precipitation method and had good dispersibility in water. These nanoparticles modified by PEI were combined with negatively charged pACTERT-EGFP via electrostatic interaction. The transfection efficiency of the magnetic nano-gene vector with the magnetic field was determined by a fluorescence-inverted microscope and flow cytometry. The results showed significant improvement compared with the control group (p < 0.05). The magnetic complexes also exhibited up to 6-times higher transfection efficiency compared with commonly used PEI or lipofectin. On the basis of these results, the antitumor effect with suicide gene therapy using pACTERT-TRAIL in vitro and vivo was evaluated. In vitro apoptosis was determined with the Annexin V-FITC Apoptosis Detection Kit. The results suggested that PEI-modified Fe(3)O(4) nanoparticles could mediate the killing of Tca83 cells. Furthermore, treatment with pACTERT-TRAIL delivered by magnetic nanoparticles showed a significant cytostatic effect through the induction of apoptosis in a xenograft model. This indicates that magnetic nano-gene vectors could improve the transgene efficiency for Tca83 cells and could exhibit antitumor functions with the plasmid pACTERT-TRAIL. This may be a new way to treat OSCC.

Use of CBCT to investigate the root canal morphology of mandibular incisors.

PURPOSE: To investigate the root canal morphology of mandibular incisors using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: A total of 353 patients with 1,412 healthy, well-developed mandibular incisors were enrolled. Radiographic examination by CBCT was conducted as part of their routine examination, diagnosis and treatment planning. The following observations were made using CBCT: (1) the number of roots; (2) the number of canals; (3) canal configuration according to Vertucci's classification; (4) the position of root canal bifurcations. RESULTS: Two canals were found in 10.9 % of mandibular central incisors, 25.5 % of lateral incisors and in 18.2 % of all the 1,412 mandibular incisors. Significantly, more lateral incisors possessed two canals than central incisors (p < 0.05). Of the teeth with two canals, type III incisors were the most prevalent, followed by types II, IV and V. Furthermore, 37.7 % of teeth were found to have root canal bifurcations that were at or near to the cortical-middle third junction regions of the roots. CONCLUSION: Routine mode CBCT imaging was clinically useful for detection of two canals and determines the position of root canal bifurcations in mandibular incisors.

[A comparative study of the cytotoxicity of five dental bonding agents to human periodontal ligament cells].

PURPOSE: To compare the cytotoxicity of 5 different dental bonding agents to human periodontal ligament cells(HPDLCs). METHODS: Primary cultured HPDLCs were exposed to different concentrations (100%,50% and 25%) of Super Bond, Clearfil SE Bond, G-Bond, Single Bond2, and Adper Easy One for different times (24 h, 48 h and 72 h). Cytotoxicity of 5 different agents to HPDLCs were observed by MTT method. The data was analyzed using SPSS 19.0 software package. RESULTS: Cytotoxicity of 5 dentin bonding agents to HPDLCs were Super Bond0.05). CONCLUSIONS: Cytotoxicity of 5 dentin bonding agents are different. Cytotoxicity of Super-bond C&B,G-Bond and Clearfil SE Bond are weak, while cytotoxicity of Single Bond2 is the strongest among the 5 agents. Supported by Medical Leading Talents and Innovation Team Project of Jiangsu Province (LJ201110) and Natural Science Foundation of Jiangsu Province (SBK201340904).

A new dental curriculum for chinese research universities.

The current dental curriculum in China was developed from the system in the Soviet Union in the 1950s. This curriculum is outdated and must be reformed to keep pace with the developments of modern dental education. The new dental educational system should be customized to China's needs: care for a large population with poor overall oral health, operating within a government-owned, centralized health care delivery system. Chinese research universities have a mission to produce competent dentists who will also be educators and researchers. To efficiently train academic dentists who can also meet the clinical needs of today's Chinese population, a new dental curriculum was developed at the Institute and Hospital of Dentistry, Nanjing University Medical School. This curriculum has four main features: 1) a two-year general higher education plus five-year dental education ("2+5") model; 2) improved integration of didactic and practical learning; 3) improved integration of dental education with research training; and 4) improved overall sequencing of the entire curriculum. This article describes the details of this new dental curriculum.

[Detection and analysis of comE and luxS genes in quorum sensing signal pathway from Streptococcus oralis].

OBJECTIVE: To detect and analyze two important genes, comE and luxS, in quorum sensing signal pathway from Streptococcus oralis (S. oralis). METHODS: The total genomic DNA of S. oralis NH521 (a clinically isolated strain) was firstly extracted. The comE and luxS genes were then amplified by polymerase chain reaction (PCR) and further sequenced. The obtained sequences were compared with related sequences in GenBank. RESULTS: Target bands of both comE and luxS genes were detected by electrophoresis. The obtained gene sequences were similar to the corresponding sequences from another S. oralis strain (luxS, 95.0%; comE, 99.6%); however, comparing to gene sequences of another species Streptococcus mutans, comE was more divergent (12.7%) than luxS gene (74.1%). CONCLUSION: This study successfully amplified and sequenced comE and luxS genes from S. oralis NH521 strain. The luxS gene accumulated more mutations than comE gene did between two S. oralis strains, but comE gene is more divergent than luxS gene between two Streptococcus species.

[Analysis of mandibular bone mineral density of senile osteoporosis patients].

OBJECTIVE: To investigate the mandibular bone mineral density (BMD) change of senile osteoporosis patients and the relationship between the mandible bone loss and systemic bone loss. METHODS: Forty senile osteoporotic patients (group A), 40 non-osteoporosis control elders (group B) and 40 healthy youths (group C) were included in this study. Standard digital panoramic tomography (SDPTG) was taken for each participant. Cortical width (CW), panoramic mandibular index (PMI), alveolar bone density and alveolar bone height were measured on the SDPTG. Lumbar and hip BMD were measured with dual energy X-ray absorptiometry (DXA). RESULTS: Close relationship was found between CW (3.57 +/- 0.82) and systemic BMD for osteoporosis patients (P < 0.05). All the SDPTG indices including CW, PMI, alveolar bone density and alveolar bone height were different for osteoporosis patients from the healthy youths (P < 0.05). The osteoporosis patients had thinner CW (3.57 +/- 0.82) and smaller PMI (0.29 +/- 0.06) than non-osteoporosis control elders (CW: 4.07 +/- 0.75, PMI: 0.32 +/- 0.07, P < 0.05). The alveolar bone density (105.40 +/- 20.48) and alveolar bone height (10.42 +/- 1.82) of the non-osteoporosis control elders reduced compared with the healthy youths (alveolar bone density: 117.10 +/- 22.23, alveolar bone height: 11.69 +/- 1.63, P < 0.05). CONCLUSIONS: The senile osteoporotic patients had significant mandibular cortical bone loss.

[Evaluation of mandibule bone loss of periodontitis with standard digital panoramic tomogram].

OBJECTIVE: To compare the mandibular indices differences between periodontitis and non-periodontitis subjects by digital panoramic tomograms in order to find a simple and effective method to evaluate the density of alveolar bone and study the relativity between local bone loss and systemic bone loss. METHODS: Standard digital panoramic tomograms of sixty periodontitis subjects and sixty non-periodontitis subjects were taken. Density and height cortical width (CW) and panoramic mandibular index (PMI) of alveolar bone were measured on the digital panoramic tomograms. SPSS 12.0 was used for statistics analyses. RESULTS: The periodontitis subjects had lower height of alveolar bone (8.76 mm vs. 11.85 mm, P=0.000), lower density of alveolar bone (106.08 vs. 113.33, P=0.034), thinner cortical width (3.80 mm vs. 4.27 mm, P=0.008), while the difference of PMI between the two groups was not significant (P>0.05). The relativity between both density and height of alveolar bone with CW was significant (P<0.05), but not significant with PMI (P>0.05). CONCLUSION: The optical method is a simple and effective method to measure the density of the alveolar bone. Compared with the non-periodontitis subjects, the periodontitis subjects not only have alveolar bone changed significantly but also have thinner cortical width.