The Chinese journal of dental research : the official journal of the Scientific Section of the Chinese Stomatological Association (CSA)最新文献

Objective: To evaluate the microshear bond strength (μSBS) of resin cement to a lithium disilicate glass ceramic conditioned with different surface treatment procedures.

Methods: Crystallised slices of lithium disilicate glass ceramic were randomly divided into five groups (n = 10) according to different surface treatment procedures: the no surface treatment (NT) group was untreated; the hydrofluoric acid (HF) group was conditioned with 4.5% HF; the silane (S) group was conditioned with a silane coupling agent; the hydrofluoric acid and silane (HFS) group was conditioned with HF followed by the silane coupling agent; and the Monobond Etch & Prime (MEP) (Ivoclar Vivadent, Schaan, Liechtenstein) group was conditioned with the one-step self-etching primer MEP. Resin cement was applied to the ceramic surfaces and irradiated. A μSBS test was performed. Failure analysis, surface roughness tests, surface topography examination and elemental analysis were also conducted. The data were analysed with a one-way analysis of variance (ANOVA) and Tukey honestly significant difference test (P < 0.05).

Results: The MEP group resulted in comparable μSBS to the HFS group (16.9 ± 4.3 MPa and 16.0 ± 2.2 MPa, respectively), but a significantly higher μSBS than the NT (1.0 ± 0.9 MPa), HF (8.9 ± 3.9 MPa) and S (12.6 ± 2.5 MPa) groups. Adhesive failure was mainly observed in the NT and HF groups, while the S, HFS and MEP groups demonstrated the most mixed failure. Though micrographs revealed a roughened surface in the HF group, no significant difference was found with any other groups.

Conclusion: Within the limitations of this study, it can be concluded that the μSBS of resin cement to lithium disilicate glass ceramic etched with MEP is as efficient as that treated with HF and silane.

Objective: To estimate the prevalence and distribution of tooth wear among groups of adolescents and adults in Shanghai, China through an epidemiological survey, and explore the associated factors.

Methods: Multistage, stratified, constant volume and cluster sampling methods were used in an epidemiological survey conducted in Shanghai in 2014. The basic erosive wear examination (BEWE) index was used to screen for tooth wear in different age groups: 12 years, 15 years, 18 to 35 years, 36 to 49 years and 50 to 74 years. A previously published questionnaire collected information including dietary habits, oral hygiene habits and general conditions.

Results: This survey reports the results for 1806 participants in Shanghai. The prevalence of tooth wear was 59.7% in adolescents (BEWE ≥ 1) and 93.1% in adults (BEWE ≥ 2). The prevalence and severity of disease increased with age (P < 0.01). The teeth most susceptible to wear were the central incisors and first molars. Multivariate analysis of covariance (ANCOVA) results showed that soft drinks, alcoholic drinks, pickled vegetables and hard food, gastroesophageal reflux disease (GERD), xerostomia and poor tooth brushing habits were statistically correlated with tooth wear in different age groups.

Conclusion: The prevalence of tooth wear appears to be high in adolescents and adults in Shanghai. Frequent consumption of soft or alcoholic drinks, GERD, xerostomia and poor tooth brushing habits were positively associated with tooth wear in different age groups.

Objective: To compare the efficiency of a new sonic powered irrigation system named EDDY (VDW, Munich, Germany), passive ultrasonic irrigation (PUI) and conventional needle irrigation (CNI) in root canal sealer penetration.

Methods: A total of 45 mandibular premolars were instrumented up to size 30, 0.9 taper and randomly divided into three groups (n = 15) depending on the final irrigation activation technique: EDDY, PUI or CNI. After the final irrigation procedures, the root canals were obturated with labelled sealer mixed with 0.1% rhodamine B. Transverse sections at 3, 5 and 7 mm from the root apex were examined using confocal laser scanning microscopy. The maximum depth and total area and percentage of sealer penetration were measured using ImageJ analysis software (National Institutes of Health, Bethesda, MD, USA).

Results: In the EDDY group, the penetration depth was higher compared to the CNI group in the apical and middle sections and compared to the PUI group in the apical section (P ˂ 0.05). The penetration area in the EDDY group was higher compared to the CNI group in all sections and compared to the PUI group in the coronal section (P ˂ 0.05). The percentage of penetration was higher in the EDDY group compared to the CNI group in all sections and compared to the PUI group in the coronal section (P ˂ 0.05).

Conclusion: In the present study, sealer penetration was superior in the EDDY group than the CNI group in the apical section. In the middle and coronal sections, sealer penetration was similar for the EDDY and PUI groups.

The endoplasmic reticulum has emerged as a modulator that is essential for cellular homeostasis and human health. It is an extensive membranous organelle that acts as a hub for the physiological and pathological processes. In recent years, it has become a topic of interest in studies on the relationship between endoplasmic reticulum homeostasis and system diseases. Periodontal disease is a prevalent chronic disease that affects tooth-supporting tissues, initiated by the interaction between pathogenic bacterial infection and immune defence and resulting in tooth loss. The endoplasmic reticulum participates in the responses to the fluctuating microenvironments in periodontal pathogenesis and regulates periodontal homeostasis. In this review, we present an overview of the significance of endoplasmic reticulum regulation as a multidimensional mediator in periodontal disease and highlight the potential strategies for periodontal regeneration.

Objective: To develop a novel chondrocyte condensation culture strategy recapitulating developmental condensation and construct self-organised cartilaginous tissue for cartilage regeneration.

Methods: Cell-condensation aggregate (CCA) was generated using the condensation culture method by sequential cell seeding. The chondrification capacities and biocompatibilities of CCA were assessed by comparison with the cell-scaffold complex (CSC), which was constructed by cell-scaffold coculture. Preclinical studies including implantation into nude mice subcutaneously and cartilage defect repair in rabbits were performed.

Results: CCA constructed by condensation culture exhibited a morphology of self-organised cartilaginous tissue. Meanwhile, the condensation culture inhibited or abolished expression of HOX genes including HOXC4 and HOXD8, which was partially consistent with developmental HOX gene expression patterns and associated with enhanced regeneration capacities. Compared with CSC, CCA showed a higher capacity for chondrification and regeneration of rabbit cartilage defects.

Conclusion: The therapeutic assessments indicate that CCA is an efficient therapeutic tool for cartilage regeneration, providing a new strategy for tissue engineering by mimicking developmental events.

Objective: To determine the crosstalk of osteogenesis and osteoclastogenesis of alveolar bone in lipopolysaccharide (LPS)-induced periodontitis in mice.

Methods: A representative periodontitis model was established by treating mice with LPS, and osteoblasts and osteoclasts were cultured. Osteoblasts and osteoclasts were cocultured to determine the effects of LPS on the crosstalk of osteogenesis and osteoclastogenesis. Quantitative polymerase chain reaction (qPCR) was performed to determine the expression of osteoclastogenesis makers underlying the potential mechanisms.

Results: The morphological and pathological changes in alveolar bone were observed in LPSinduced mice and LPS dose-dependently suppressed osteogenesis. The mRNA expression of cathepsin K, as a marker of osteoclasts, was accordingly downregulated in the coculture. The mRNA expression of osteoprotegerin was increased, while that of receptor activator of nuclear factor-κB ligand (RANKL) was decreased with an increased concentration of LPS. Moreover, the mRNA expression of toll-like receptor 4 (TLR4) was upregulated by LPS, whereas TLR4 knockout partially recovered osteoclast differentiation in the upper layer of the coculture.

Conclusion: LPS dose-dependently suppressed osteogenesis but had a bidirectional effect on osteoclastogenesis. The combined effects of LPS on osteogenesis, osteoclastogenesis and their crosstalk via TLR4 account for alveolar bone loss in periodontitis.

Objective: To explore the potential therapies for infantile haemangiomas by targeting survivin, a member of the inhibitor of apoptosis protein family, using its specific small molecule inhibitor YM155.

Methods: The expression of survivin in human haemangioma tissue was explored using immunohistochemistry and immunohistofluorescence. Cell cycle analysis and EdU assays were used to measure cell proliferation. Heochst33342 and Annexin V/PI double staining were performed to measure cell apoptosis. The capacity for self-renewal and multilineage differentiation potential of haemangioma stem cells (HemSCs) were measured by clone formation assays and multiple differentiation assays. Murine haemangioma models were established to explore the therapeutic efficacy of YM155 in vivo.

Results: Strong staining of survivin in stromal cells was observed in the proliferative haemangioma tissue. In vitro studies demonstrated that YM155 induced cell cycle arrest and proliferation suppression of HemSCs, and also caused cell apoptosis at a higher concentration. YM155 impaired the self-renewal capacities and damaged multiple differentiation potentials of HemSCs. Importantly, YM155 suppressed blood vessel formation and cell proliferation, and induced cell apoptosis in murine haemangioma models.

Conclusion: The present study demonstrated that targeting survivin using its specific suppressant, YM155, prevented the progression of infantile haemangioma by suppressing cell proliferation, inducing cell apoptosis and disrupting the differentiation potential of HemSCs. These results indicate a novel and promising therapeutic approach for the treatment of infantile haemangioma.

To describe the current scientific knowledge concerning stem cells obtained from the pulp of discarded primary teeth and to discuss their contribution to dental tissue engineering, a narrative review of the relevant literature published in the past decade (2010-2019) in the PubMed database was conducted. The promise that stem cells from human exfoliated deciduous teeth (SHED) hold as a viable biological option to heal diseased dental organs has been the focus of research over the past decade. New ways of inducing higher levels of differentiation through various bioactive agents and scaffolds have been pursued. Attention has also been paid to the regeneration potential of the discarded pulp tissue that originates from high caries risk or inflamed teeth. In conclusion, the field of stem cell engineering is constantly evolving, and although there is still much to learn about the behaviour of SHED, there are endless opportunities for their exploitation in dental regeneration.

Objective: To compare the accuracy of electronic apex locators in the presence of blood and CBCT images obtained with two different voxel sizes (0.125 mm and 0.25 mm) in determining root canal length up to the perforation area.

Methods: Forty extracted, single-rooted human teeth were selected and an artificial root perforation (0.4 ± 0.1 or 1.0 ± 0.2 mm diameter) was created in the middle third of the root. The actual root canal length up to the perforation area was determined under a stereomicroscope. CBCT images were obtained with a voxel size of 0.125 mm and 0.25 mm. The root canal length up to the perforation area was measured on CBCT images and recorded as the radiographic length. The teeth were embedded in alginate and root canal length up to the perforation area was measured using two different EALs (DentaPort ZX [Morita, Tokyo, Japan] and Gold Reciproc motor [VDW, Munich, Germany]) and recorded as the electronic length.

Results: In teeth with an artificial root perforation 0.4 mm in diameter, the measurements obtained with DentaPort ZX were more accurate than with the Gold Reciproc motor (P ˂ 0.05), and on CBCT images, more accurate measurements were obtained with a voxel size of 0.125 mm compared to 0.25 mm (P ˂ 0.05). In teeth with an artificial root perforation 1.0 mm in diameter, the radiographic length was closer to actual length than the electronic length (P ˂ 0.05).

Conclusion: In artificial root perforations with a diameter of 0.4 mm, CBCT gives more reliable results than EALs. Both EAL and CBCT measurements were closer to actual length in artificial perforations that were 1.0 mm in diameter.

Objective: To evaluate the outcome of systematic video training on tooth preparation in veneer restoration and the practicability of the application of the digital evaluation system of scan design and assessment software.

Methods: Ten residents were selected from a group enrolled on the first-year programme for the National Standard Training of Dentistry in the Department of Prosthodontics, College of Stomatology, Ninth People's Hospital Affliated with Shanghai Jiao Tong University, School of Medicine. First, each student prepared five teeth based on their knowledge and clinical experience, and then received systematic video training on veneer preparation. Before and after the training, the evaluation of the effects of training was conducted on the prepared teeth by measuring the continuity of the finishing line and tooth reduction amount automatically using the prepCheck 2.0 (Dentsply Sirona, Charlotte, NC, USA) CAD/CAM system.

Results: The results showed a significant difference in the quality of finishing line continuity pre- and post-training. Furthermore, the data for tooth reduction after training, which met standard values, improved remarkably, increasing from 32.40 ± 7.82% to 60.50 ± 5.48%.

Conclusions: Video training could significantly enhance the quality of tooth preparation for veneers. Moreover, the digital evaluation system could serve as an ideal alternative for tooth preparation evaluation for preclinical students, offering new insights for clinical education.