Y. Gao

Bio: Y. Gao is an academic researcher from Sichuan University. The author has contributed to research in topics: Content analysis & Sodium hypochlorite. The author has an hindex of 1, co-authored 1 publications receiving 296 citations.

Irrigation in endodontics.

Abstract: Irrigation is a key part of successful root canal treatment. It has several important functions, which may vary according to the irrigant used: it reduces friction between the instrument and dentine, improves the cutting effectiveness of the files, dissolves tissue, cools the file and tooth, and furthermore, it has a washing effect and an antimicrobial/antibiofilm effect. Irrigation is also the only way to impact those areas of the root canal wall not touched by mechanical instrumentation. Sodium hypochlorite is the main irrigating solution used to dissolve organic matter and kill microbes effectively. High concentration sodium hypochlorite (NaOCl) has a better effect than 1 and 2% solutions. Ethylenediaminetetraacetic acid (EDTA) is needed as a final rinse to remove the smear layer. Sterile water or saline may be used between these two main irrigants, however, they must not be the only solutions used. The apical root canal imposes a special challenge to irrigation as the balance between safety and effectiveness is particularly important in this area. Different means of delivery are used for root canal irrigation, from traditional syringe-needle delivery to various machine-driven systems, including automatic pumps and sonic or ultrasonic energy.

[Effect of porous zirconia ceramics on proliferation and differentiation of osteoblasts].

Abstract: OBJECTIVE To investigate the effect of porous surface morphology of zirconia on the proliferation and differentiation of osteoblasts. METHODS According to different manufacturing and pore-forming methods, the zirconia specimens were divided into 4 groups, including milled sintering group (M-Ctrl), milled porous group (M-Porous), 3D printed sintering group (3D-Ctrl) and 3D printed porous group (3D-Porous). The surface micromorphology, surface roughness, contact angle and surface elements of specimens in each group were detected by scanning electron microscope (SEM), 3D laser microscope, contact angle measuring device and energy-dispersion X-ray analysis, respectively. MC3T3-E1 cells were cultured on 4 groups of zirconia discs. The cell morphology of MC3T3-E1 cells on zirconia discs was eva-luated on 1 and 7 days by SEM. The cell proliferation was detected on 1, 3 and 5 days by cell counting kit-8 (CCK-8). After osteogenic induction for 14 days, the relative mRNA expression of alkaline phosphatase (ALP), type Ⅰ collagen (Colla1), Runt-related transcription factor-2 (Runx2) and osteocalcin (OCN) in MC3T3-E1 cells were detected by real-time quantitative polymerase chain reaction. RESULTS The pore size [(419.72±6.99) μm] and pore depth [(560.38±8.55) μm] of 3D-Porous group were significantly larger than the pore size [(300.55±155.65) μm] and pore depth [(69.97±31.38) μm] of M-Porous group (P < 0.05). The surface of 3D-Porous group appeared with more regular round pores than that of M-Porous group. The contact angles of all the groups were less than 90°. The contact angles of 3D-Ctrl (73.83°±5.34°) and M-Porous group (72.7°±2.72°) were the largest, with no significant difference between them (P>0.05). Cells adhered inside the pores in M-Porous and 3D-Porous groups, and the proliferation activities of them were significantly higher than those of M-Ctrl and 3D-Ctrl groups after 3 and 5 days' culture (P < 0.05). After 14 days' incubation, ALP, Colla1, Runx2 and OCN mRNA expression in 3D-Porous groups were significantly lower than those of M-Ctrl and 3D-Ctrl groups (P < 0.05). Colla1, Runx2 and OCN mRNA expressions in M-Porous group were higher than those of 3D-Porous group (P < 0.05). CONCLUSION The porous surface morphology of zirconia can promote the proliferation and adhesion but inhibit the differentiation of MC3T3-E1 cells.

Space evidence: an oral interview interview corroboration method research based on generative space analysis

Abstract: Abstract. The oral interview is an essential component of heritage study fieldwork. However, due to the individual memory bias, quick verification of the content's validity about the built environment is required. This paper aims to provide an efficient method for verifying the authenticity of oral interviews by combining architectural heritage data with digital analysis techniques and using spatial analysis as evidence. The method is based on the image pre-processing of existing architectural drawings, the creation of multiple planes and models through parametric variation factors matrix, and the generation of analysis images using daylight analysis algorithms. The Pix2Pix model is also introduced as a basis for tagging the planes and the images of the analysis results according to its principles. Learning by pairing the labeled images enables the computer to generate image analysis based on a given plane figure for fast analysis in the built environment. Following this, the authenticity of the oral interview’s content can be quickly determined. This paper examines the industrial heritage of the Puqi Textile General Factory, which was formed under the idea of rapid construction during the Third Front construction, using the factory ’s built environment and related oral content as the basis for analysis and verification. The findings did not satisfy the poor working conditions described in the oral interviews. Therefore, the authenticity of the oral content is doubtful and requires further verification.

Effectiveness of curcumin against Enterococcus faecalis biofilm

Abstract: Objectives. To evaluate the antimicrobial efficacy of curcumin against Enterococcus faecalis biofilm formed on tooth substrate in vitro. Sodium hypochlorite (NaOCl) and chlorhexidine (CHX) served as standards for comparison. Materials and methods. Biofilms of E.faecalis were formed on instrumented, extracted human teeth (n = 96). At the end of the 2nd day, 2nd and 8th weeks, specimens were treated for 30 min with one of the test solutions or saline (control) and the surviving colony-forming units (CFU/mL) was recorded. Results were analyzed by Kruskal-Wallis test and Dunnet test for pair-wise comparison with Bonferroni correction (p = 0.05). Results. Only NaOCl showed complete eradication of bacteria at all time periods. In the 2-day and 2nd week biofilms, curcumin and NaOCl showed complete inhibition, which was significantly lower than the CFU recovered in the CHX and saline groups (p < 0.05). In 8 week biofilms, samples treated with curcumin showed 553 ± 137.6 CFU/mL, which was significantly higher than NaOCl (0 CFU/mL), but significantly lower than CHX (2551 ± 129.8) and saline control (1.42 1011 ± 2.12 1010; p < 0.05). Conclusions. Sodium hypochlorite (3%) showed maximum antibacterial activity against E.faecalis biofilm formed on the tooth substrate, followed by curcumin and CHX. Considering the potential for undesirable properties of NaOCl, the use of herbal alternatives in endodontics might prove to be advantageous.

Ex vivo evaluation of four final irrigation protocols on the removal of hard‐tissue debris from the mesial root canal system of mandibular first molars

Abstract: Aim To evaluate the efficacy of four final irrigation protocols on the reduction of hard-tissue debris accumulated within the mesial root canal system of mandibular first molars using micro-CT analysis. Methodology Forty mesial roots of mandibular molars with a single and continuous isthmus connecting the mesiobuccal and mesiolingual canals (Vertucci's Type I configuration) were selected and scanned at a resolution of 8.6 μm. Canals were enlarged sequentially using WaveOne Small and Primary instruments activated in reciprocating motion without intracanal irrigation to allow debris to accumulate within the mesial root canal system. Then, specimens were anatomically matched and distributed into four groups (n = 10), according to the final irrigation protocol: apical positive pressure (APP), passive ultrasonic irrigation (PUI), Self-adjusting File (SAF) and XP-endo Finisher (XPF). The final irrigation procedures were performed over 2 min using a total of 5.5 mL of 2.5% NaOCl per canal. Reconstructed data sets were coregistered, and the mean percentage reduction of accumulated hard-tissue debris after the final irrigation procedures was compared statistically between groups using the anovapost hoc Tukey test with a significance level set at 5%. Results Reduction of accumulated hard-tissue debris was observed in all groups after the final irrigation protocol. Overall, PUI and XPF groups had higher mean percentage reductions of accumulated hard-tissue debris (94.1% and 89.7%, respectively) than APP and SAF groups (45.7% and 41.3%, respectively) (P 0.05) or APP and SAF groups (P > 0.05). Conclusions The PUI technique and XP-endo Finisher instrument were associated with significantly lower levels of AHTD compared with conventional irrigation and the modified SAF system protocol in mesial root canals of mandibular molars.