The aim of this study was to evaluate and compare the colour stabilities of three types of orthodontic clear aligners exposed to staining agents in vitro. Sixty clear orthodontic aligners produced by three manufacturers (Invisalign, Angelalign, and Smartee) were immersed in three staining solutions (coffee, black tea, and red wine) and one control solution (distilled water). After 12-h and 7-day immersions, the aligners were washed in an ultrasonic cleaner and measured with a colourimeter. The colour changes (ΔE*) were calculated on the basis of the Commission Internationale de I'Eclairage L*a*b* colour system (CIE L*a*b*), and the results were then converted into National Bureau of Standards (NBS) units. Fourier transformation infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) were conducted to observe the molecular and morphologic alterations to the aligner surfaces, respectively. The three types of aligners exhibited slight colour changes after 12 h of staining, with the exception of the Invisalign aligners stained with coffee. The Invisalign aligners exhibited significantly higher ΔE* values (ranging from 0.30 to 27.81) than those of the Angelalign and Smartee aligners (ΔE* values ranging from 0.33 to 1.89 and 0.32 to 1.61, respectively, P<0.05). FT-IR analysis confirmed that the polymer-based structure of aligners did not exhibit significant chemical differences before and after the immersions. The SEM results revealed different surface alterations to the three types of aligner materials after the 7-day staining. The three types of aesthetic orthodontic appliances exhibited colour stability after the 12-h immersion, with the exception of the Invisalign aligners stained by coffee. The Invisalign aligners were more prone than the Angelalign and Smartee aligners to pigmentation. Aligner materials may be improved by considering aesthetic colour stability properties.

The sublabial transsphenoidal approach has been the gold standard for pituitary surgery for many years. However, meta-analysis of the recent literature demonstrates superior outcomes and decreased postoperative complications with the endoscopic approach, potentially justifying a shift toward endoscopic pituitary surgery.

In HPDLFs, MDP and LPS activated NLRP3 inflammasome and induced IL-1β secretion. ASC plays an important role in this inflammatory response.

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Aim To explore the function and mechanisms of NLRP6 (NOD‐, LRR‐ and pyrin domain‐containing 6) in the inflammatory response of human periodontal ligament cells (HPDLCs). Methodology Tissues associated with apical periodontitis were obtained from three patients who underwent endodontic microsurgery. The expression of NLRP6 in 3 human apical periodontitis tissues and HPDLCs was examined by immunohistochemistry and immunofluorescence, respectively. The expressions of NLRP6, Phospho(p)‐ p65, p65, IκB‐α, p‐ IκB‐α, ERK, p‐ ERK, NLRP3, Pro interleukin (IL)‐1β, Pro caspase‐1 and apoptosis‐associated speck‐like protein containing a CARD (ASC) were examined by western blot. The gene expression and secretion of proinflammatory cytokines were detected using quantitative real‐time polymerase chain reaction and enzyme‐linked immunosorbent assay. Data were analysed statistically with independent sample t‐tests. Results NLRP6 was expressed in inflammatory periapical tissues and HPDLCs. Lipopolysaccharide (LPS) from Escherichia coli induced NLRP6 in HPDLCs (P < 0.05). After silencing NLRP6, E. coli LPS‐induced activation of NF‐κB and ERK signalling was enhanced, which was also accompanied by elevated levels of IL‐6 and tumour necrosis factor‐α (TNF‐α) (P < 0.05). Moreover, knockdown of NLRP6 led to up‐regulation of NLRP3, Pro IL‐1β and Pro caspase‐1 (P < 0.05), whereas down‐regulation of ASC (P < 0.05), which may contribute to unchanged levels of IL‐1β in HPDLCs inflammation. Conclusion NLRP6 was functionally expressed in inflamed periapical tissues and HPDLCs. NLRP6 negatively regulated the production of IL‐6 and TNF‐α in HPDLCs inflammation by inhibiting NF‐κB and ERK signal pathways.