Chinese Journal of Dental Research, 03/2023

Maintaining the viability and avoiding necrosis of dental pulp are crucial to preserving the structural integrity and functioning of teeth. In recent years, cell-based regenerative endodontics has emerged as a promising approach to achieve this goal and has gained increasing attention in scientific research; however, in the confined space of the root canal system, hypoxic conditions can be both beneficial and detrimental, as they may promote angiogenesis in the graft to some extent but also lead to tissue necrosis if prolonged. Dental pulp stem cells (DPSCs) have been verified as multipotent cells that can promote angiogenesis and are therefore ideal candidates for realising real dental pulp regeneration within root canals. Thus, we focus on the underlying mechanisms of DPSCs to promote angiogenesis and summarise some preclinical studies and clinical trials involving transplanting of DPSCs to achieve real dental pulp regeneration, in the hope that this intractable source of perplexity in regenerative endodontics may be resolved sooner. Keywords: angiogenesis, dental pulp stem cell, pulp regeneration, pulp repair, regenerative endodontics

Nanotechnology is a rapidly evolving field with numerous biological applications and is becoming increasingly significant due to its immense potential to enhance the properties of orthodontic and biomaterials. It is employed in various emerging areas of orthodontics, focusing on improving the performance of diverse orthodontic appliances and accessories, as well as nanoelectromechanical systems (NEMS) and nanorobots. Nevertheless, the biocompatibility and cytotoxicity of nanomaterials in orthodontic applications require further investigation. This paper reviews the latest applications of nanomaterials in orthodontics, elucidates their unique features and synergistic applications in orthodontics, and outlines prospective developments in the field. Keywords: clinical application, nanomaterials, orthodontics

Objective: To explore the high-efficiency and low-risk prevention and treatment strategies for stem cells from human exfoliated deciduous teeth (SHED) for high-altitude cerebral oedema. Methods: A low-pressure and low-oxygen tank mimicking high-altitude conditions was used to establish the high-altitude cerebral oedema animal model. The preventive effects of SHED for cerebral oedema were then evaluated by haematoxylin and eosin (H&E) and histological staining. In vitro, SHED was co-cultured with BV-2 to analyse the effects of SHED by western blot and immunofluorescence staining. Results: SHED can prevent and treat cerebral oedema in a high altitude rat animal model. Mechanistically, SHED treatment can protect brain cells from apoptosis induced by high altitude condition. Moreover, SHED treatment can inhibit M1-type polarisation and promote M2-type polarisation of microglia cells via the suppression of hypoxia inducible factor (HIF)- 1α-mediated extracellular signal-regulated kinase (ERK) signalling activated in high altitude condition. Conclusion: SHED treatment can relieve high-altitude cerebral oedema via inhibiting HIF- 1α-mediated ERK signalling, which indicates that SHED is a promising alternative strategy to prevent and treat high-altitude cerebral oedema. Keywords: cerebral oedema, microglia, polarisation, SHED, stem cells

Objective: To evaluate the saliva level of α1 and β1 adrenergic receptors (ARs) in oral lichen planus (OLP) patients. Methods: This case-control study included unstimulated saliva samples from 33 OLP patients (14 erosive, 19 non-erosive) and 33 healthy controls. All participants were evaluated on psychological conditions via the Depression, Anxiety and Stress Scale – 21 items (DASS 21). The saliva levels of α1 and β1 ARs was measured by enzyme-linked immunosorbent assay (ELISA). Data were analysed with a t test using SPSS 25 (IBM, Armonk, NY, USA). Results: The saliva levels of α1 and β1 ARs of OLP patients (both erosive and non-erosive forms) were significantly higher than in healthy controls. Stress levels in patients with both forms of OLP were significantly higher than in the healthy group. There was a positive correlation between salivary α1 and β1 ARs and stress, and this positive correlation was also seen for saliva β1 ARs between anxiety or depression. The saliva level of α1 ARs was inversely correlated with unstimulated salivary flow rates (r = −0.246; P = 0.046). Conclusion: This study indicated that OLP patients with both erosive and non-erosive forms have higher psychological stress and saliva levels of α1 and β1 ARs than healthy controls; however, the role of α1 and β1 ARs as salivary markers with regard to the development, severity of symptoms and outcome of OLP needs further investigation. Keywords: adrenergic receptors, oral lichen planus, saliva, stress

Objective: To investigate the dental caries status and periodontal status of disabled children and adolescents aged 0 to 18 years in China and provide suggestions for future policies. Methods: The cross-sectional survey included disabled children and adolescents aged 0 to 18 years in welfare institutions across 10 provinces in eastern, central and western regions in China, between November 2013 and May 2015. Oral health examination included dental caries status and periodontal status. The mean score for decayed, missing and filled teeth (dmft/ DMFT) due to caries in primary/permanent dentition, gingival bleeding rate and calculus rate were recorded and statistically evaluated. Data analysis was performed using SPSS 24.0 software (IBM, Armonk, NY, USA), and the level of statistical significance was P < 0.05. Results: The mean dmft/DMFT values of for groups aged 0 to 5, 6 to 12 and 13 to 18 years were 1.48 ± 3.00, 2.19 ± 2.94 and 1.78 ± 2.93, respectively. The mean scores for the groups aged 0 to 5 (P < 0.05) and 13 to 18 years (P < 0.01) showed a significant difference among different disability types. A significant difference between sexes was found only in the group aged 0 to 5 years (P < 0.05). Gingival bleeding rates were 13.70% for the group aged 0 to 5 years, 24.81% for the group aged 6 to 12 years and 42.06% for the group aged 13 to 18 years, and calculus rates were 5.48%, 22.41% and 47.62% for the three age groups, respectively. The gingival bleeding rate for all three age groups showed a significant difference between different disability types (P < 0.01), whereas calculus rates a showed significant difference only in the groups aged 6 to 12 and 13 to 18 years (P < 0.01). Conclusion: The prevalence of dental caries, gingival bleeding and calculus in disabled children and adolescents in China is high. Disability type was strongly associated with oral health status. Specially designed oral health education and training are necessary for clinical professionals and caregivers.

Objective: To test the null hypothesis that dentine treatment with silver diamine fluoride (SDF), a potent antimicrobial agent, following use of proteolytic and chelating agents does not influence the wettability of an epoxy resin (AH Plus, Dentsply Sirona, Charlotte, NC, USA) and a tricalcium silicate sealer (BioRoot RCS, Septodont, Saint-Maur-des-Fossés, France). Methods: Seventy-two intraradicular dentine specimens were divided into six groups based on the final irrigation solutions used: 2.5% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid (EDTA) (NaOCl-EDTA) (group 1); NaOCl-EDTA-NaOCl (group 2); NaOCl-EDTA followed by 3.8% SDF, NaOCl-EDTA-SDF (group 3); NaOCl-EDTA-NaOCl-SDF (group 4); SDF (group 5) and saline (group 6). After irrigation, the specimens were divided into subgroups according to the sealer used, AH Plus or BioRoot RCS. Contact angles were measured using a contact angle analyser. The data were analysed using an independent t test, one-way analysis of variance (ANOVA) and Tamhane T2 post hoc test, with the level of significance set at P < 0.05. Results: In the epoxy resin sealer group, dentine surfaces treated with only SDF showed the lowest contact angle. This was significantly less than the groups in which NaOCl was used as the final irrigant (P < 0.05). In the tricalcium silicate–based sealer group, the groups treated with SDF showed significantly greater contact angles when compared to the control group (P < 0.05). Conclusion: It was concluded that SDF conditioning of dentine favours the wettability of epoxy resin sealer but is detrimental to the wettability of tricalcium silicate sealer. Keywords: bioceramic sealer, contact angle, epoxy resin sealer, ethylenediaminetetraacetic acid, silver diamine fluoride, sodium hypochlorite