Effect of leukocyte and platelet rich fibrin (L-PRF) on stability of dental implants. A systematic review and meta-analysis

The aim of this study was to assess the impact, if any, of L-PRF application in an implant bed prior to implant placement, focusing on stability by means of implant stability quotient (ISQ) values. The literature was searched in a systematic way by means of the main databases and hand searching of the most relevant journals. The inclusion and exclusion criteria were used to determine the eligible studies included in this review. Only randomised controlled trials (RCT) and controlled clinical trials (CCT) were included. A total of four RCTs were included for data extraction. The risk of bias was deemed moderate to unclear. Meta-analysis was performed to assess the effect of L-PRF, on implant stability, immediately post-insertion in three studies, after one week from the implant placement in three studies and after four weeks for all the included studies. The fixed effects model has shown Hedges g statistic for the one week varying from 0.380 to 1.401 with a pooled figure of 0.764 (95% CI 0.443 to 1.085) and for four weeks varying between 0.74 and 1.1 with a combined effect of 0.888 (95% CI 0.598 to 1.177). The results for both intervals were in favour of the use of L-PRF while the statistical difference immediately post-insertion was not statistically significant. The present systematic review, though acknowledging its limitations, suggests that L-PRF has a positive effect on secondary implant stability and that needs to be correlated to the clinical practice to measure the actual clinical effect by means of reducing treatment times.     

Er，Cr：YSGG激光对牙周炎患牙及健康牙根面的影响

目的：探讨应用RFPT5-14工作尖的Er, Cr: YSGG激光照射对牙周炎患牙及健康牙根面微观结构改变以及粗糙度的影响。方法：选取8颗因牙周炎拔除的患牙，用超声刮治器去除根面牙石，另选取8颗因正畸减数或阻生智齿拔除的健康牙，将每颗牙根面分为4个区域，对应为1~4组，分别进行如下4种处理：（1）不处理；（2）Gracey刮治器进行根面平整30 s；（3）低功率激光照射30 s；（4）高功率激光照射30 s。通过扫描电镜观察表面微观结构，通过三维光学轮廓仪测量表面粗糙度Ra值。结果：手工根面平整组的表面可见玷污层覆盖；激光照射组表面较清洁，可见消融样改变；高功率激光组可见局部有牙本质小管暴露。牙周炎患牙第1组的Ra值为（237.4±20.0） nm，第2~4组的Ra值分别为（135.7±11.9） nm（P=0.01）、（463.6±49.3） nm（P<0.001）和（486.0±59.0） nm（P<0.001）。健康牙第1组的Ra值为（191.4±44.5）nm，第2~4组的Ra值分别为（131.6±21.5） nm（P=0.482）、（463.7±34.6） nm（P<0.001）和（470.3±121.3） nm（P<0.001）。结论：应用RFPT5-14工作尖的Er, Cr: YSGG激光照射可造成牙周炎表面的病变牙骨质及健康牙表面的健康牙骨质微观结构的改变，可以有效减少根面玷污层，并可见有消融样改变。Er, Cr: YSGG激光照射可以增加根面粗糙度，还需进一步实验来评价激光照射后根面的生物相容性。     

细胞外基质PDMS硬度对牙髓干细胞增殖和成骨分化的影响

目的: 研究细胞外基质聚二甲基硅氧烷（polydimethylsiloxane,PDMS）硬度对牙髓干细胞（DPSCs）增殖和成骨分化的影响及其机制。方法: 收集南京医科大学附属常州市第二人民医院因正畸而拔除的前磨牙作为实验材料,分离、培养DPSCs,制作PDMS基质。根据不同硬度,将PDMS基质分为A组（基料/固化剂=10∶1,硬度135 kPa）、B组（基料/固化剂= 20∶1,硬度54 kPa）和C组（基料/固化剂= 30∶1,硬度16 kPa）,另设不含PDMS基质的对照组,在各组基质上培养DPSCs细胞,采用CCK-8法检测各组DPSCs细胞培养至1、3、5、7天时的增殖率,采用茜素红染色鉴定各组DPSCs细胞成骨效果,采用蛋白免疫印迹法（Western blot）检测各组DPSCs细胞中骨钙素（OCN）、RUNX2、细胞外因子1（Wnt1）、β连环素（β-catenin）蛋白表达量。采用SPSS 22.0软件包对数据进行统计学分析。结果: 茜素红染色结果显示,A组DPSCs细胞形态发生明显变化,排列具有明显方向性,由多角形、梭形逐渐变为方形,出现钙化小结节,B组钙化小结节明显少于A组,C组钙化小结节明显少于B组,对照组钙化小结节极少。B组DPSCs细胞各时刻增殖率及OCN、RUNX2、Wnt1、β-catenin蛋白表达量均显著低于A组（P<0.05）,C组DPSCs细胞各时刻增殖率及OCN、RUNX2、Wnt1、β-catenin蛋白表达量显著低于B组（P<0.05）,对照组DPSCs细胞各时刻增殖率及OCN、RUNX2、Wnt1、β-catenin蛋白表达量显著低于C组（P<0.05）。结论: 较硬细胞外基质可能通过激活Wnt/β-catenin信号通路,促进牙髓干细胞增殖和成骨分化,这可为牙周组织工程新材料的研发提供理论基础。     

龋病防治的临床难度评估

龋病是发生于牙体硬组织的慢性感染性疾病,具有发病率高、治疗率低等特点,严重危害口腔和全身健康。加强和完善龋病的规范化治疗是全人群、全生命周期龋病管理面临的关键问题。因此,在龋病诊断和分类的基础上,建立龋病防治临床难度评估系统,主要包括龋病风险评估和龋病治疗难度评估,可为龋病管理提供有效的依据。本文围绕龋病防治难度评估系统,从龋病的诊断和分类、龋病风险评估和龋病治疗难度评估等龋病防治临床管理的重要组成部分进行归纳与阐述。     

Work-related skin and airway symptoms among Swedish dentists rarely cause sick leave or change of professional career

Dentistry usually is 'wet work' with risk of damage to the skin barrier, and the hands may be exposed to skin irritants and contact-sensitizing substances used in dental materials or gloves. Airway irritants may also be present. This study assessed the consequences of work-related skin and airway symptoms among dentists in terms of contact with health authorities, sick leave, or changes in the professional career. A questionnaire on these factors was answered by more than 3000 Swedish dentists. Only 6% of the respondents had consulted a physician, although 22% had noted work-related skin symptoms. In 2% the skin symptoms had caused sick leave, and about 2% had reported their skin symptoms as an occupational disease. Two per cent had consulted a physician owing to work-related airway symptoms, which is a minor part of the 13% who had experienced such symptoms when in contact with dental materials. Twenty-five dentists (<1%)had been on sick leave because of work-related airway symptoms. Only 19 dentists reported change of activities or occupation owing to work-related skin or airway symptoms, and in most cases these symptoms only contributed to their decision. In summary, whereas sick leave in dentists because of musculoskeletal problems may be common, the present study shows that this is not the case for workrelated skin or airway symptoms, and such symptoms seldom affect the dentists' professional career.     

Risk of bleeding after dentoalveolar surgery in patients taking anticoagulants

To avoid increasing the risk of thromboembolic events, it is recommended that treatment with anticoagulants should be continued during dentoalveolar operations. We have evaluated the incidence of bleeding after dentoalveolar operations in a prospective study of 206 patients, 103 who were, and 103 who were not, taking anticoagulants. Seventy-one were taking thrombocyte aggregation inhibitors and 32 vitamin K antagonists. Patients were treated according to guidelines developed at the Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands. The operations studied included surgical extraction (when the surgeon had to incise the gingiva before extraction), non-surgical extraction, apicectomy, and placement of implants. Patients were given standard postoperative care and those taking vitamin K antagonists used tranexamic acid mouthwash postoperatively.