The critical barrier to progress in dentine bonding with the etch-and-rinse technique

Objectives

The lack of durability in resin-dentine bonds led to the use of chlorhexidine as MMP-inhibitor to prevent the degradation of hybrid layers. Biomimetic remineralisation is a concept-proven approach in preventing the degradation of resin-dentine bonds. The purpose of this study is to examine the integrity of aged resin-dentine interfaces created with a nanofiller-containing etch-and-rinse adhesive after the application of these two approaches.

Methods

The more established MMP-inhibition approach was examined using a parallel in vivo and in vitro ageing design to facilitate comparison with the biomimetic remineralisation approach using an in vitro ageing design. Specimens bonded without chlorhexidine exhibited extensive degradation of the hybrid layer after 12 months of in vivo ageing.

Results

Dissolution of nanofillers could be seen within a water-rich zone within the adhesive layer. Although specimens bonded with chlorhexidine exhibited intact hybrid layers, water-rich regions remained in those hybrid layers and degradation of nanofillers occurred within the adhesive layer. Specimens subjected to in vitro biomimetic remineralisation followed by in vitro ageing demonstrated intrafibrillar collagen remineralisation within hybrid layers and deposition of mineral nanocrystals in nanovoids within the adhesive.

Conclusions

The impact was realized by understanding the lack of an inherent mechanism to remove water from resin-dentine interfaces as the critical barrier to progress in bonding with the etch-and-rinse technique. The experimental biomimetic remineralisation strategy offers a creative solution for incorporating a progressive hydration mechanism to achieve this goal, which warrants its translation into a clinically applicable technique.     

p53基因抑制涎腺腺样囊性癌细胞端粒酶及增殖活性

目的研究外源性野生型p53基因对涎腺腺样囊性癌细胞的抑制作用。方法构建携带野生型p53基因的腺病毒表达载体，以脂质体法转染涎腺腺样囊性癌SACC-83细胞，RT-PCR检测p53基因表达；采用TRAP—PCR—ELISA法检测转染细胞端粒酶活性，荧光素酶分析法检测人端粒酶逆转录酶基因（hTERT）肩动子的转录；流式细胞术、软琼脂集落实验及裸鼠成瘤实验观察细胞生物特性的变化。结果外源性野生型p53基因导入使p53基因在涎腺腺样囊性癌细胞SACC-83中表达增强，其端粒酶活性降低、hTERT启动子转录抑制；转染细胞出现G1期阻滞，软琼脂集落形成率减少，裸鼠成瘤能力降低。结论腺病毒载体介导的外源性野生型p53基因可以抑制涎腺腺样囊性癌细胞端粒酶活性及细胞恶性表型。     

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目的探讨螺旋CT三维重建技术在埋伏尖牙正畸牵引中的应用价值。方法2006年3月至2007年12月,南京大学医学院附属口腔医院正畸科对12例颌骨内尖牙埋伏阻生患者进行螺旋CT检查、颌面骨三维重建,并与曲面断层X线片进行对比观察。结果CT三维重建能对颌骨内埋伏阻生尖牙准确定位,与颌骨内的实际情况所见完全一致,极大的提高了埋伏尖牙正畸牵引的成功率,有效地缩短了患者的治疗时间,减少了患者的痛苦。结论螺旋CT三维重建影像可以直观地显示埋伏阻生尖牙在颌骨内的生长情况,对上颌骨埋伏阻生尖牙的定位、治疗方案的制定具有重要指导作用。     

NF-κB信号转导通路和肿瘤发生、转移关系的研究进展

大量研究表明,NF-κB信号转导通路可以促进肿瘤的发生.许多炎症因子、致癌剂、促癌剂和肿瘤微环境都可以激活NF-κB.NF-κB蛋白本身和其调控的蛋白与肿瘤的发生、增殖、抗凋亡、侵袭、血管生成和转移有关.在多种肿瘤中NF-κB都处于持续性激活状态.本文就NF-κB信号通路和肿瘤发生和转移之间关系的研究新进展做一综述.     

Beyond冷光牙齿漂白技术对人牙髓影响的组织病理学研究

目的 探讨Beyond冷光牙齿漂白技术对牙髓的影响.方法 选择因正畸要拔除的40颗活髓牙,对照组(10颗)不做任何处理拔除,其余30颗采用Beyond冷光漂白后分别即刻拔除(15颗)和漂白七天后拔除(15颗).40颗牙齿均制作病理切片,镜下观察牙髓组织形态.结果 所有活髓牙漂白前后均未发现有任何临床症状.漂白后即刻拔除组、七天后拔除组以及对照组在镜下均表现为正常的牙髓组织结构,漂白组较对照组牙髓组织无明显改变.结论 Beyond冷光牙齿漂白技术对活髓牙牙髓无明显不良影响,是一项安全可靠的漂白技术.     

Dental caries and chemical warfare within the mouth

To date, it appears that the dentists' war against dental caries has no end in sight due to the fact that dentists lack any genuine offensive firepower. Make no mistake, the defense has drastically improved as dentists have shifted the focus more toward the preventive aspects of dental care. But defense by itself cannot defeat the enemy; at best, it can maintain the status quo. In order to defeat the enemy, one must study and understand the enemy, to know its strengths and weaknesses, and to strike at those points of vulnerability. The aim of this research is to identify and characterize genes that are responsible for observed virulence factors in Streptococcus mutans, which is the primary pathogen involved in the development of dental caries. Once there is a more defined understanding of the many virulence factors of S. mutans, there will be a much more valuable insight into its role in the ecology of the oral cavity. Eventually, this knowledge could enable dentists to convert the bacterial "weaponry" into its own arsenal, which could then be innovatively employed as preventive, diagnostic, and therapeutic agents to treat oral bacterial-related diseases.     

切牙先天缺失患者颅颌面形态分析

目的 了解福建地区切牙先天缺失患者的颅颌面形态特征,探讨切牙先天缺失对颌面部生长发育的影响.方法 将78例切牙先天缺失患者分为3组:L1组,先天缺失1颗下切牙;L2组,先天缺失2颗下切牙;U2组,先天缺失2颗上颌侧切牙;12例个别正常牙合作为对照组.对受试者头颅侧位片进行头影测量分析.结果 与对照组比较,L1组ANB增大(P＜0.05),其余指标无明显差异;L2组ANB、SNA、UL-EL增大,N-S-Ar减小(P＜0.05);U2组H角、L1-NB、MP-SN、N-ANS、NA-PA、N-Me、N-S-Ar减小,SNB增大,U1-L1增大(P＜0.05).结论 下颌切牙先天缺失患者上颌骨相对前突,上颌侧切牙先天缺失患者下颌前突,呈Ⅲ类骨型趋向.上、下切牙缺失对颅颌面结构具有不同的影响.     

冠状切口在颧骨复合体骨折中的应用

目的探讨颧骨复合体骨折复位和固定术中应用冠状切口入路的手术适应证、手术方法及减少并发症的措施。方法84例颧骨复合体骨折的患者应用单纯冠状切口为36.9%、冠状切口 下睑缘切口为32.1%、冠状切口 下睑缘切口 前庭沟切口为16.7%和冠状切口 前庭沟切口为14.3%。术中患者均使用微型钛板或小型钛板坚强内固定。对于眶底骨折出现眼球内陷的患者以羟基磷灰石人工骨进行眶底重建。结果84例患者均未发生手术后切口感染,术后随访3个月到2年,无面神经永久性损伤,术后所有咬合关系紊乱的患者均达到功能性咬合。通过训练后张口度得到满意恢复。8例患者术后患侧颧弓处仍稍显膨隆。术后眼球内陷只有1例仍大于3mm,其余均恢复满意。结论颧骨复合体骨折使用头皮冠状切口时,熟练掌握颞部的解剖层次是至关重要的,仔细保护神经及血管结构可减少手术并发症。     

全冠边缘材料与位置对人牙周组织的影响

目的 探讨全冠边缘材料和位置对人牙周组织的影响.方法 对需作全冠或双端固定桥修复并符合纳入标准的20例患者的30颗牙,在牙体预备前、全冠或双端固定桥黏固后7～8周,分别记录其颊侧牙龈的菌斑指数(PLI)、牙周探诊深度(PD)、龈沟出血指数(SBI),并测量其龈沟液(GCF)量、龈沟液的天冬氨酸转氨酶活性(AST活性).全冠或固定桥黏固前后分别测量冠边缘间隙.暂时冠和全冠黏固后对患者各行1次口腔健康教育.结果 全冠黏固后7～8周,全冠对应牙龈的PD、 SBI≥2频率、GCF量及AST活性没有明显变化, PLI≥1的频率明显下降.结论 具有良好的口腔卫生习惯、制作精良的全冠黏固后7～8周,金属边缘、烤瓷边缘、平龈冠边缘、龈下冠边缘均不会引起人牙龈的不良反应.