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Background Human dental pulp stromal cells (hDPSCs) are promising sources of mesenchymal stem cells (MSCs) for bone tissue regeneration. Circular RNAs (circRNAs) have been demonstrated to play critical roles in stem cell osteogenic differentiation. Herein, we aimed to investigate the role of circAKT3 during osteogenesis of hDPSCs and the underlying mechanisms of its function. Methods We performed circRNA sequencing to investigate the expression profiles of circular RNAs during osteogenesis of hDPSCs. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to detect the expression pattern of circAKT3 and miR-206 in hDPSCs during osteogenesis. We knocked down circAKT3 and interfered the expression of miR-206 to verify their regulatory role in hDPSC osteogenesis. We detected hDPSCs mineralization by alkaline phosphatase (ALP) and Alizarin Red S (ARS) staining and used dual-luciferase reporter assay to validate the direct binding between circAKT3 and miR-206. To investigate in vivo mineralization, we performed subcutaneous transplantation in nude mice and used hematoxylin and eosin, Masson’s trichrome, and immunohistochemistry staining. Results Totally, 86 circRNAs were differentially expressed during hDPSC osteogenesis, in which 29 were downregulated while 57 were upregulated. circAKT3 was upregulated while miR-206 was downregulated during hDPSC osteogenesis. Knockdown of circAKT3 inhibited ALP/ARS staining and expression levels of osteogenic genes. circAKT3 directly interacted with miR-206, and the latter one suppressed osteogenesis of hDPSCs. Silencing miR-206 partially reversed the inhibitory effect of circAKT3 knockdown on osteogenesis. Connexin 43 (CX43), which positively regulates osteogenesis of stem cells, was predicted as a target of miR-206, and overexpression or knockdown of miR-206 could correspondingly decrease and increase the expression of CX43. In vivo study showed knockdown of circAKT3 suppressed the formation of mineralized nodules and expression of osteogenic proteins. Conclusion During osteogenesis of hDPSCs, circAKT3 could function as a positive regulator by directly sponging miR-206 and arresting the inhibitive effect of miR-206 on CX43 expression.

The study aimed to assess trials investigating the effect of PBMT on mini-implant stability. Electronic searches of seven databases and manual search were conducted up to May 2020. Randomized controlled trials and controlled clinical trials evaluating the effect of PBMT on mini-implant stability were included. The risks of bias of individual studies were performed using ROB 2.0 and ROBINS-I-tool based on different study design. Meta-analysis was conducted to compare mini-implant stability exposed to PBMT with control ones at different time points after implantation. Among the 518 records initially identified, seven studies were included in this study. Six studies investigated low-level laser therapy (LLLT) and one study evaluated light-emitting diode (LED) therapy. Two studies were eligible for meta-analysis, which showed that LLLT significantly improved mini-implant stability 60 days after initial implantation (MD - 3.01, 95% CI range [- 4.68, - 1.35], p = 0.0004). High energy density of LLLT began to show beneficial effect on mini-implant stability as early as 3 days after implantation, while the significant effect of low energy density displayed later than 30 days after insertion. LED therapy could improve mini-implant stability after 2 months post-insertion. In conclusion, PBMT appears to be beneficial in ameliorating mini-implant stability. High energy density of LLLT might exert more rapid effect than low energy density. More high-quality clinical trials are needed to further demonstrate PBMT' effects on orthodontic mini-implants.

Clear aligners have been frequently applied in orthodontic clinic practice. However, its effect on oral health-related quality of life (OHRQoL) compared with fixed appliance treatment (FAT) remains inconclusive. This systematic review aimed to compare the impacts of clear aligner treatment (CAT) with FAT on patients' OHRQoL. Electronic searches of databases (PubMed, Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, Embase, Medline, two Chinese databases and six grey literature databases) were conducted up to July 2019. Randomized controlled trials, controlled clinical trials, cohort studies and cross-sectional studies comparing the impact of CAT and FAT on OHRQoL with validated instruments were included. Extraction of data and assessment of the risk of bias were conducted using ROBINS-I-tool, Newcastle-Ottawa Scale and ROB 2.0 based on study design. Of the 1112 records initially identified, 2 studies were included in this review. One study evaluated OHRQoL at the last debonding appointment, while the other made evaluation at the early stage of treatment. In the aspect of functional dimensions, both studies reported less eating disturbance in CAT patients than FAT ones. Based on currently limited information, the effect of CAT on the overall OHRQoL compared to FTA was still inconclusive. In individual dimensions, however, weak evidence supported that CAT might cause less eating disturbance than FAT. More high-quality clinical trials using validated OHRQoL instruments are needed to draw more reliable conclusions in the effect of CAT and FAT on OHRQoL.