Colour stabilities of three types of orthodontic clear aligners exposed to staining agents

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 （△E＊） 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 AE＊ values （ranging from 0.30 to 27.81） than those of the Angelalign and Smartee aligners （AE＊ values ranging from 0.33 to 1.89 and 0.32 to 1.61, respectively, P〈O.05）. IFT-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.

Survival and prognostic factors of non-small cell lung cancer patients with postoperative locoregional recurrence treated with radical radiotherapy

Background: Locoregional recurrence remains the challenge for long-term survival of non-small cell lung cancer(NSCLC) patients after radical surgery, and curative-intent radiotherapy could be a treatment choice. This study aimed to assess the survival and prognostic factors of patients with postoperative locoregionally recurrent NSCLC treated with radical radiotherapy.Methods: We reviewed medical records of 74 NSCLC patients with postoperative locoregional recurrence who received radical radiotherapy between April 2012 and February 2016 at Sun Yat-sen University Cancer Center(Guangzhou, China). The efficacy and safety of radical radiotherapy were analyzed. The probability of survival was estimated using the Kaplan-Meier method and compared using the log-rank test. The Cox proportional hazards model was used to identify prognostic factors.Results: Grade 3/4 adverse events included neutropenia(8 cases, 10.8%), esophagitis(7 cases, 9.5%), pneumonitis(1 case, 1.4%), and vomiting(1 case, 1.4%).The 2-year overall survival, progression-free survival, local recurrencefree survival(LRFS), and distant metastasis-free survival(DMFS) rates of all patients were 84.2,42.5,70.0, and 50.9%,respectively. Univariate and multivariate analyses showed that a higher biological effective dose(BED) of radiation was associated with longer LRFS [hazard ratios(HR)=0.317,95% confidence interval(CI) = 0.112-0.899, P = 0.016] and that wild-type epidermal growth factor receptor(EGFR) was associated with longer DMFS compared with EGFR mutation(HR = 0.383,95% CI=0.171-0.855, P = 0.019).Conclusions: Radical radiotherapy is effective and well-tolerated in NSCLC patients with postoperative locoregional recurrence. High BED is a predictor for long LRFS, and the presence of wild-type EGFR is a predictor for long DMFS.

非小细胞肺癌术后局部复发患者接受根治性放疗的生存及预后因素

背景与目的局部复发是影响根治性手术后非小细胞肺癌(non?small cell lung cancer,NSCLC)患者长期生存的重要因素之一,而根治性放疗可作为解决这一问题的可选治疗方案。本研究旨在评价接受根治性放疗的NSCLC术后局部复发患者的生存和预后因素。方法回顾2012年4月至2016年2月期间,在中山大学肿瘤防治中心接受根治性放疗的74例NSCLC术后局部复发患者的病历资料,分析根治性放疗的疗效和安全性。采用Kaplan-Meier法估算患者生存率,并用log-rank检验进行比较,采用Cox回归模型进行单、多因素分析。结果 3/4级不良事件包括中性粒细胞减少(8例,10.8%)、放射性食管炎(7例,9.5%)、放射性肺炎(1例,1.4%)和呕吐(1例,1.4%)。所有患者的2年总生存率、无进展生存率、局部无复发生存(local recurrence?free survival,LRFS)率和无远处转移生存(distant metastasis?free survival,DMFS)率分别为84.2%、42.5%、70.0%和50.9%。单因素和多因素分析显示,较高的生物等效剂量(biological effective dose,BED)与较长的LRFS相关(风险比[hazard ratios,HR]=0.317,95%置信区间[confidence interval,CI]:0.112–0.899,P=0.016),与表皮生长因子受体(epidermal growth factor receptor,EGFR)突变型患者相比,EGFR野生型患者的DMFS较长(HR=0.383,95%CI:0.171–0.855,P=0.019)。结论对于NSCLC术后局部复发患者应用根治性放疗治疗是安全有效的。BED与LRFS呈正相关,EGFR野生型患者DMFS较长。