The influence of surface modification techniques on the performance of a Y-TZP dental ceramic

OBJECTIVES: The purpose of the current study was to examine the influence of the pre-cementation surface modification techniques, namely alumina abrasion and surface grinding, routinely employed by dental practitioners prior to cementation and placement of crown and bridge restorations on the performance of a Y-TZP dental ceramic. METHODS: Twelve sets of 30 Lava ceramic discs (13 mm diameter, 1.5mm thickness) supplied by the manufacturer were randomly selected. Six groups were abraded utilising 25, 50 and 110 microm alumina and stored dry or in a water bath at 37+/-1 degrees C for 24 h. Four groups were ground utilising a fine or a coarse grit diamond bur, specimens were ground dry or while using water as a coolant. The mean bi-axial flexure strengths, standard deviations and associated Weibull moduli (m) were determined. The surface roughness, hardness and phase composition were assessed utilising profilometry, the Vicker's hardness indentation and X-ray diffraction, respectively. RESULTS: No significant difference (P > 0.05) was identified in the bi-axial flexure strength of the 25, 50 and 110 microm alumina-abraded and the control specimens stored dry and wet for 24h. However, a significant increase in m was identified for the alumina-abraded specimens stored dry (10.7+/-1.9, 10.6+/-1.9 and 10.6+/-1.9) compared with the control (7.5+/-1.3) and the specimens stored in a water bath. In addition, the alumina abrasion regimes reduced the surface roughness compared with the controls. The coarse grinding regime significantly reduced both the bi-axial flexure strength and the associated m compared with the control whilst no significant difference was identified for the fine grinding regimes. The surface modification techniques initiated a phase transformation mechanism and resulted in the formation of a layer of compressive stresses on the surface of the disc-shaped specimens. CONCLUSIONS: The combination of the reduced surface roughness and the formation of a surface layer of compressive stress as a result of the alumina abrasion regimes investigated increased the reliability of the bi-axial flexure strength. The presence of water in the current study did not detrimentally influence the performance of the Y-TZP ceramic under investigation. Coarse grinding significantly reduced the bi-axial flexure strength and m due to the increased surface roughness. The Y-TZP specimens in the current investigation underwent a toughening mechanism as a result of a phase transformation mechanism which generated a transformation compressive stress that opposes the externally applied, crack-propagating tensile stress.     

屈侧网状色素沉着一家系调查

报告屈侧网状色素沉着的一家系调查,该家系4代人中共有15例患者,其中男9例,女6例,多数患者于10岁以后发病,表现为典型的屈侧色素沉着。组织病理检查显示表皮突向下延伸呈细丝状或棒状。     

Splenic flexure cancer survival: a 25-year experience and implications for complete mesocolic excision (CME) and central vascular ligation (CVL)

Background

The management of splenic flexure cancers (SFCs) in the era of complete mesocolic excision (CME) and central vascular ligation (CVL) is challenging because of its variable lymphatic drainage. This study aimed to compare survival outcomes for SFCs and non-SFCs, and better understand the clinicopathological characteristics which may define a distinct SFC phenotype.

Methods

An observational cohort study at Concord Hospital, Sydney was conducted with patients who underwent resection for colon adenocarcinoma (1995–2019). Clinicopathological data were extracted from a prospective database. Overall survival (OS) and disease-free survival (DFS) estimates and their associations to clinicopathological variables were investigated with Kaplan–Meier and Cox regression analyses.

Results

Of 2149 patients with colon cancer, 129 (6%) had an SFC. The overall 5-year OS and DFS rates were 63.6% (95% CI 62.5–64.7) and 59.4% (95% CI 58.3–60.5), respectively. SFCs were not associated with OS (P = 0.6) or DFS (P = 0.5). SFCs were more likely to present urgently (P < 0.001) with obstruction (P < 0.001) or perforation (P = 0.03), and more likely to require an open operation (P < 0.001). These characteristics were associated with poorer survival outcomes. No differences were noted between SFCs and non-SFCs with respect to tumour stage (P = 0.3).

Conclusion

SFCs have a distinct phenotype, the individual characteristics of which are associated with poorer survival. However, the survivals of SFCs and non-SFCs are similar, possibly because the most important determinant of outcome, tumour stage, is no different between the groups. This may have implications for the surgical approach to SFCs with respect to standardization of CME and CVL surgery for these cancers.     

横结肠癌网膜弓淋巴结转移的预后价值

目的:探讨横结肠癌网膜弓淋巴结转移的预后价值。方法:采用倾向评分匹配及回顾性队列研究方法。收集2010年11月至2017年11月福建医科大学附属协和医院收治的371例横结肠癌病人的临床病理资料;男202例,女169例;中位年龄为58岁,年龄范围为21~92岁。病人均由同一组外科医师施行全结肠系膜切除+网膜弓淋巴结清扫术...     

颈椎生理曲度改变的X线表现及其临床意义

目的 分析颈椎生理曲度改变的X线表现及其临床意义.方法 125例临床怀疑颈椎生理曲度异常的病例均摄颈椎正侧位、双斜位片,摄片时患者头颈部体位为立位听鼻线平行于水平面.在颈椎侧位片上测量椎体前缘序列弧线的弧弦距.结果 在125例中,颈椎生理曲度轻度变直见于76例（60.8%）,颈椎生理曲度明显变直或消失32例（25.6%）,颈椎生理曲度呈节段性向后凸出13例（10.4%）,以及颈椎椎体间发生局限性偏移或错位4例（3.2%）.结论 颈椎生理曲度改变的X线表现,在排除外伤等其他因素后,可提示颈椎病的诊断.     

Ectopic Pancreas in the Duodenojejunal Flexure—Computed Tomographic and Endoscopic Ultrasonographic Images

Ectopic pancreas is a rare entity where the pancreatic tissue has no anatomic and vascular contact with the main body of the pancreas and has its own duct system and vascular supply. A detailed clinical report with contrast-enhanced computed tomography (CT) and endoscopic ultrasonography (EUS) imaging findings of a 40-year-old male came with vague symptoms. CT showed a well-defined homogeneously enhancing mass lesion in the duodenojejunal (DJ) flexure. EUS revealed a well-defined hypoechoic mass lesion in the submucosal layer of the DJ flexure. Surgical resection of the mass was performed, and histopathological examination of specimen confirmed the pancreatic tissues. Here, we have described the CT and EUS imaging features which can help to differentiate the ectopic pancreas from the gastrointestinal submucosal tumours.     

Atmospheric moisture effects on the testing rate and cementation seating load following resin-strengthening of a soda lime glass analogue for dental porcelain

Objectives

To investigate if resin-cementation of a soda lime glass dental analogue could elucidate information regarding the pattern of resin-reinforcement when coated in an environment actively scavenged of moisture.

Methods

192 soda lime disc-shaped specimens (alumina particle air abraded, hydrofluoric acid-etched and silane coated) were randomly assigned to eight groups (n = 24 per group) prior to resin-coating at seating loads of 5 N (Groups A–D) and 30 N (Groups E–H) in an environment where moisture was actively scavenged and maintained below 15 ppm. Following one week storage the discs were tested in biaxial flexure at crosshead rates of 0.01, 0.1, 1 and 10 mm/min. Analysis of group means was performed utilising a general linear model univariate analysis and post hoc all paired Tukey tests (P < 0.05).

Results

The general linear model univariate analysis identified the mean biaxial flexure strength (BFS) was significantly influenced by the factors resin-cementation seating load (P < 0.001) and crosshead speed of the applied load (P < 0.001) with a significant interaction (P = 0.008) between both factors. The linear logarithmic regression curves fitted to the group mean BFS data plotted against the crosshead speed highlighted significant differences between the pattern of resin-strengthening for the cementation loads and testing conditions.

Conclusions

The decrease in resin-penetration expected within the ‘resin-ceramic hybrid layer’ following removal of the 30 N seating load was proposed as the modifying resin-strengthening parameter. These observations are supported by the viscoelastic and creep behaviour of resins at slow testing rates which becomes the dominant or determining phenomenon.     

腹腔镜辅助Soave手术治疗小儿结肠脾曲综合征的临床体会

目的:探讨腹腔镜辅助Soave手术治疗小儿结肠脾曲综合征的治疗效果与安全性。方法:回顾分析2005²012年为52例结肠脾曲综合征患者行腹腔镜辅助Soave手术的临床资料。患儿均以反复便秘为主要临床表现,钡剂灌肠检查脾曲较肝曲升高>1.52012年为52例结肠脾曲综合征患者行腹腔镜辅助Soave手术的临床资料。患儿均以反复便秘为主要临床表现,钡剂灌肠检查脾曲较肝曲升高>1.5².0椎体,脾曲夹角<45度,横结肠扩张,降结肠冗长。结果:52例手术均获成功,手术时间802.0椎体,脾曲夹角<45度,横结肠扩张,降结肠冗长。结果:52例手术均获成功,手术时间80⁹5 min,平均(88±5.32)min;术中出血量295 min,平均(88±5.32)min;术中出血量2⁵ ml,平均(3±0.78)ml;切除肠管225 ml,平均(3±0.78)ml;切除肠管22⁴2 cm,平均(36±2.26)cm;术后24 h肠鸣音恢复,肛门排气或排便,术后恢复饮食时间142 cm,平均(36±2.26)cm;术后24 h肠鸣音恢复,肛门排气或排便,术后恢复饮食时间1² d。术后体温≤37.5℃。腹部切口甲级愈合率100%。术后肛周轻度污粪2例,无一例发生切口感染、结肠回缩、夹层感染、切口疝等并发症。术后随访82 d。术后体温≤37.5℃。腹部切口甲级愈合率100%。术后肛周轻度污粪2例,无一例发生切口感染、结肠回缩、夹层感染、切口疝等并发症。术后随访8⁸5个月,平均(62±5.42)个月,效果满意;随小儿年龄的增长,大便次数逐渐减少,远期大便285个月,平均(62±5.42)个月,效果满意;随小儿年龄的增长,大便次数逐渐减少,远期大便2⁴次/d。结论:腹腔镜辅助Soave手术具有操作简单、创伤轻、出血少、并发症少、安全、切口美观等优点,是治疗小儿结肠脾曲综合征的理想术式。     

结肠脾曲肿瘤左半结肠切除术与扩大右半结肠切除术临床对比研究

目的探讨左半结肠切除术（LC）对比扩大右半结肠切除术（RC）对结肠脾曲肿瘤患者疗效状况。 方法回顾性分析2010年10月至2012年10月成都市第七人民医院进行手术治疗的结肠脾曲肿瘤患者90例,其中行LC手术42例（LC组）,行RC手术48例（RC组）。观察两组患者手术情况（R0切除率、手术死亡率、手术时间、术中出血量、淋巴结清扫数情况）,以及术后排气时间、住院时间、阳性淋巴结和二次手术状况,随访分析手术后并发症、平均生存期及1、3、5年生存率,ELISA法检测手术前后患者血清白细胞介素6、10（IL-6、IL-10）及γ-干扰素（IFN-γ）质量浓度的改变。 结果两组患者R0切除率、手术死亡率、手术时间、术中出血量、淋巴结清扫数、术后排气时间、住院时间和二次手术对比差异无统计学意义。LC组患者并发症率为16.67%,RC组为18.75%,差异无统计学意义。术后两组患者血清IL-10、IL-6质量浓度较术前降低,IFN-γ较术前升高,差异均有统计学意义（P<0.05）;RC组患者平均生存期和1、3年生存率高于LC组,差异有统计学意义（Log-rank=12.027、13.491,P=0.038、0.014）。 结论RC手术长期疗效略优于LC手术,结肠脾曲肿瘤患者手术前确定淋巴结回流路径和肿瘤血供评估将更有利于患者选取合适手术方式。