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Periodontal ligament (PDL) cells play an important role in mechanosensing and secretion of signaling molecules during bone remodeling. However, the regulatory mechanism is unknown. The aim of the present study is to investigate the expression pattern of periostin and sclerostin in response to orthodontic forces in periodontal ligament cells in vitro. PDL cells were isolated from extracted teeth and treated with compressive forces of 25 gr/cm 2 or equiaxial tension forces at frequency 1 Hz for 0, 24, 48, and 72 h. qRT-PCR was applied to evaluate the gene expressions. The secretion of sclerostin and periostin was assessed using ELISA. DAPI staining was used to evaluate apoptosis. The expression of sclerostin elevated significantly at protein and gene levels under compression forces after 24 h, while the application of tensile forces induced the expression of periostin and its upstream regulator RUNX2 (p < 0.05). Gene expression up-regulation was significant for POSTN and RUNX2 after 48 and 72 h tensile forces. Also, the gene expression of sclerostin reduced in a time-dependent manner after application of tensile force. The compression forces enhanced apoptosis to 7.5 ± 3.5% and induced gene expression of apoptotic markers of CASP9, and BCL2 within 72 h of exposure. Periostin and sclerostin play an important role in orthodontic loads and their expressions are affected oppositely by compressive and tensile forces that might be suggested as a biomarker for assessment of bone remodeling during orthodontic treatment., (© 2023. The Author(s), under exclusive licence to The Society of The Nippon Dental University.)

One critical tactic that leads to a better understanding of the ethical status of dentists is to assess their ethical attitude by using an appropriate scale. This study aimed to design and evaluate the validity and reliability of the ethical attitude of dentists scale (EADS). This study was conducted based on a mixed-method design. The first qualitative part of the study was conducted in 2019 and the items of the scale were produced from the ethical codes compiled in a previous study. In this part, the psychometric analysis was conducted. The reliability was evaluated by Cronbach's alpha coefficient and intraclass correlation coefficient. Factor analysis was used to assess the construct validity (n = 511), and the following three factors were extracted with a total variance of 48.03. 1) Maintaining the standing of the profession in relationships. 2) Providing dental services while maintaining trust in the profession, and 3) Providing information for the benefit of the patient. In confirmatory factor analysis, appropriate values were obtained for the goodness of fit indices, and Cronbach's alpha was 0.68 - 0.84 for the various factors. Based on the results mentioned above, this scale showed an appropriate validity and reliability for measuring the ethical attitude of dentists., Competing Interests: The authors declare no conflict of interests., (Copyright © 2022 Tehran University of Medical Sciences.)

Statement of the Problem: The risk of debonding of the orthodontic eyelets due to blood contamination from the impacted tooth is a clinical problem that orthodontists face routinely., Purpose: This study aimed to assess the effect of hemostatic agents (Viscostat clear and Astringedent X) on shear bond strength (SBS) of orthodontic eyelets bonded with conventional (Transbond XT) and universal adhesive (GC-G Premio bond) adhesives., Materials and Method: In this experimental study, 84 freshly extracted bovine lower incisors were randomly divided into 7 groups namely TBXT, Blood, SEP, VISCO + TBXT, VISCO + SEP, ASTX + TBXT, and ASTX + SEP groups. In the TBXT group, teeth were etched with phosphoric acid gel, and then, the Transbond XT primer was applied and eyelets were bonded with Transbond XT. In the blood group, first, contamination with blood was done followed by the same procedure as TBXT. In other groups, the teeth were etched with phosphoric acid and based on their group allocation, Transbond XT primer (in TBXT groups), GC-G Premio Bond (in SEP groups), ViscoStat Clear gel (in VISCO groups), or Astringedent X (in ASTX groups) were applied. The SBS was measured for each group and the adhesive remnant index (ARI) was determined., Results: The mean SBS was 20.79 MPa in VISCO+SEP group, 19.2 MPa in the TBXT group, 16.06 MPa in the SEP group, 15.43 MPa in VISCO+TBXT group, 9.39 MPa in AST-X+TBXT group, and 1.62 MPa in the blood group. The SBS of ASTX+SEP, blood and TBXT+ASTX groups had significant differences from the SBS of the control group (p< 0.05). The ARI score of 0 had the highest frequency in the blood group., Conclusion: Due to the high coagulative effect of Astringedent X and acceptable SBS of Astringedent X in combination with GC-G Premio bond, this combination can be recommended for exposure of impacted teeth that are at high risk of blood contamination., (Copyright: © Journal of Dentistry.)

Background: The porous surface of acrylic orthodontic removable appliances creates a niche for microbial plaque accumulation, and changes the oral flora by raising cariogenic bacteria including Streptococcus mutans. In this study, we evaluated the mechanical properties and antimicrobial activities of incorporating different concentrations of Curcumin-Nisin-poly(L-lactic acid) nanoparticle (CurNisNps) into orthodontic acrylic resin against Streptococcus mutans and Candida albicans., Methods: Following synthesis and characterization of CurNisNps, acrylic resin specimens with different concentrations of CurNisNps (0, 1, 2, 5, and 10% w/w) were fabricated. Flexural strength values, antimicrobial effects, anti-biofilm potential, and anti-metabolic activity against S. mutans and C. albicans were assessed at different time intervals. Also, the expression of the virulence-factor-related genes of S. mutans and C. albicans was assessed by quantitative real-time polymerase chain reaction following treatment with CurNisNps., Results: Acrylic resin containing 10% CurNisNps (30.76 ± 3.91 MPa) showed flexural failure in comparison with acrylic resin specimens without CurNisNps (50.67 ± 1.82 MPa) as the control group (P < 0.05). There was no significant decrease in the flexural strength values in samples containing 1, 2, and 5% of CurNisNps in comparison to the control group (P > 0.05). Acrylic resin with 5% CurNisNps showed the highest concentration of CurNisNps and clinically accepted flexural strength value (14.89 ± 3.26 MPa, P < 0.05) simultaneously. In the disc agar diffusion assay, 5% CurNisNps showed a high level of inhibitory activity for the test microorganisms. The reduction of growth inhibition zones of the different concentrations of CurNisNps against test microorganisms was positively associated with the time, in such a way that it was reduced significantly after 60 days. The anti-biofilm and anti-metabolic activities of acrylic resin specimens containing a 5% concentration of CurNisNps against S. mutans and C. albicans could significantly decrease the expression levels of gtfB (6.8-fold) and HWP (3.4-fold) in S. mutans and C. albicans, respectively., Conclusions: Our data support that 5% (w/w) of CurNisNps can serve as an excellent orthodontic acrylic resin additive against S. mutans and C. albicans biofilm without adverse effects on its mechanical property., (© 2022. The Author(s).)