Temperature change, dentinal fluid flow and cuspal displacement during resin composite restoration

Dentin-bonding agents and resin composite materials typically require light activation for polymerization. Light curing generates heat, which may influence dentinal fluid flow (DFF) and cuspal displacement. This study investigated the relationship among temperature increase, DFF and cuspal displacement in extracted human maxillary premolars with a mesial occlusal distal (MOD) cavity preparation. Two types of curing light were compared. Temperature changes were measured using thermocouples located on the occlusal cavity floor and at the pulp-dentine junction, during polymerization of bonding agent and resin composite material. DFF and cuspal displacement were measured simultaneously using automated flow measurement apparatus and direct current differential transformers respectively. Temperature increases of up to 15 degrees C were recorded during the restoration procedures. A quartz tungsten halogen (QTH) unit produced a significantly greater temperature increase than a light-emitting diode unit and curing of the bonding agent generated less temperature increase than curing of the resin composite. Heating due to exothermic reaction during polymerization of bonding agent and resin was not significantly different between light sources or between bonding and curing (P > 0.05). The QTH unit produced both greater inward fluid flow and cuspal displacement during the irradiation of bonding agent and resin composite than the light-emitting diode unit. There was not a simple relationship between temperature increase, fluid movement and cuspal displacement. From a clinical point of view, the light-emitting diode unit can be considered preferable to the QTH light, because it caused significantly smaller temperature increase, fluid shift and cuspal displacement.     

Effect of implant support on distal extension removable partial dentures: in vitro assessment

The implants in implant-supported removable partial dentures (RPDs) are placed in the edentulous ridge to stabilize the RPD and minimize the resultant rotational movement. This study investigated the effect of implant placement on RPD stability. A model simulating a mandibular bilateral distal extension missing was fabricated using epoxy resin and silicone impression material as thin (1 mm) and thick (2 mm) soft tissues. Five pressure sensors (PS-10K, Kyowa, Tokyo, Japan) were attached near the left and right first molars (#36 and #46), first premolars (#34 and #44) and medio-lingual alveolar crest. Five bilateral distal extension RPDs with Co-Cr frameworks were conventionally fabricated. After the implants were placed at the bilateral second molar areas, healing caps (4.5 mm high) were connected to the denture base with autopolymerized resin to support the RPD. As in a conventional RPD, sealing screws were placed without connecting them. Loads up to 5 kg were applied, and the pressure and displacement of the RPDs (n = 5) were simultaneously measured and analysed using the Wilcoxen test (alpha = 0.05). There was less pressure on both thin and thick soft tissues, the #36, #46 and the medio-lingual alveolar crest from the implant-supported RPD than from the conventional RPD (P < 0.05). There were no significant differences in pressure on #34 and #44 between the two RPDs (P > 0.05). There was significantly less denture displacement of the implant-supported RPD than of the conventional denture (P < 0.05). Implant support helped prevent the displacement of distal extension RPDs and decreased the pressure on soft tissues.     

不同置换液流量对危重患者连续静脉-静脉血液滤过治疗中去甲肾上腺素清除率的影响

目的探讨不同置换液流量的连续静脉-静脉血液滤过治疗(continuous veno-venous hemofiltration,CVVH)对危重患者血液中去甲肾上腺素清除率的影响。方法 2014年7月到2015年3月,便利抽样法选择在某三级甲等医院ICU住院且伴有急性肾损伤(acute kidney injury,AKI)接受CVVH治疗的多器官功能障碍综合征(multiple organ dysfunction syndrome,MODS)的患者30例为研究对象,所有患者均采用床旁血液净化机进行CVVH治疗,按照住院号单双号将其分为2L/h置换液组和3L/h置换液组,比较不同置换液流量下滤器对血液去甲肾上腺素清除率。结果去甲肾上腺素清除率与滤液中去甲肾上腺素浓度相关[y=2.122+0.067x,R=0.609,P0.01]。3 L/h置换液组滤器去甲肾上腺素清除率[(11.96±5.07)ml/min]大于2L/h置换液组[(7.72±2.50)ml/min],差异有统计学意义(P0.05)。结论 CVVH对去甲肾上腺素的清除率随着置换液流量的增加而增加,对于血流动力学不稳定的患者可选择低流量的置换液。     

年轻患者腰椎间盘Pfirrmann分级与椎间盘膨出及突出的相关性研究

目的通过磁共振成像,观察30岁以下腰痛患者腰椎间盘退行性改变的Pfirrmann分级特征以及相关的其他改变,并评价Pfirrmann分级与椎间盘膨出及突出的相关性。材料与方法回顾性分析83例30岁以下因腰痛行腰椎MRI检查的患者,其中男50例,女33例,平均年龄25岁。由2名影像科医师对MR图像进行分析,观察L1~S1椎间盘信号、椎间盘形态、纤维环撕裂、椎间盘膨出、椎间盘突出、椎体终板及许莫氏结节的改变。椎间盘退行性改变采用Pfirrmann分级。观察指标的相关性分析采用Pearson多元相关分析。结果纳入研究的椎间盘共415个,其中Pfirrmann分级Ⅰ~Ⅱ级退变322个(77.6%),Ⅲ级退变56个(13.5%),Ⅳ级退变33个(7.9%),Ⅴ级退变4个(1.0%);103个椎间盘出现膨出或突出;椎间盘膨出以L4~5椎间盘最多(42.2%),且多合并Ⅲ级退变(51.1%);椎间盘突出以L5~S1椎间盘最多(51.7%),且多合并Ⅳ级退变(46.6%);17例患者出现椎间盘后方高信号区(HIZ),且均位于L4~5、L5~S1椎间盘水平;3例患者出现终板退变。多元相关分析结果显示PfirrmannⅢ级退变与椎间盘膨出有明显相关性(r=0.972;P=0.006),与椎间盘突出无明显相关性(r=0.639;P=0.245);PfirrmannⅣ级退变与椎间盘突出(r=0.999,P=0.000)及HIZ(r=0.919,P=0.028)有明显相关性,与椎间盘膨出无明显相关性(r=0.769,P=0.128)。HIZ与椎间盘膨出(r=0.919,P=0.027)及突出(r=0.935,P=0.020)均有相关性。结论腰椎MRI成像能够清晰显示年轻患者椎间盘早期退行性改变的不同病理阶段;PfirrmannⅢ退变与PfirrmannⅣ级退变分别与椎间盘膨出和椎间盘突出有相关性;年轻患者应及早发现椎间盘早期退变,以对临床评价提供更有价值信息。     

白介素-1β转换酶对退变腰椎间盘组织中细胞凋亡的调节

目的观察白介素-1β转换酶(ICE)在退变腰椎间盘组织中的表达,探讨与细胞凋亡的关系。方法应用免疫组化及流式细胞术测定50例退变腰椎间盘组织和10例正常腰椎间盘组织ICE的表达及细胞凋亡率。结果腰椎间盘组织中ICE的表达部位在软骨细胞的胞浆,退变腰椎间盘组织表达阳性率为90%,高于正常腰椎间盘组织的30%,P<0.01;阳性细胞含量为(78±13)%,高于正常腰椎间盘组织的(25±10)%,P<0.01;相对蛋白含量(FI值)为1.63±0.18,高于正常腰椎间盘组织的0.56±0.09,P<0.01;退变及正常腰椎间盘组织细胞凋亡率为(71±10)%,(20±10)%;ICE表达的FI值与腰椎间盘组织细胞凋亡率呈正相关(r=0.527,P<0.05)。结论ICE参与了腰椎间盘组织中细胞凋亡的调节,并在腰椎间盘退行性变发生和发展中有一定作用。     

过屈跪位与俯卧位下L4/L5椎板间隙形态差异及其在经椎板间入路经皮内窥镜下椎间盘切除术治疗腰椎椎间盘突出症中的意义

目的测量患者全麻后过屈跪位下L4/L5椎板间隙高度和宽度,探讨其在过屈跪位下行经椎板间入路经皮内窥镜下椎间盘切除术(PEID)治疗L4/L5腰椎椎间盘突出症(LDH)中的意义。方法 2014年4月—2016年6月,采用PEID治疗L4/L5 LDH患者81例,手术体位为过屈跪位41例(过屈跪位组),俯卧位40例(俯卧位组)。用C形臂X线机正位透视测量患者摆好手术体位后L4/L5椎板间隙的高度和宽度,并进行组间比较。记录所有患者手术前后下肢痛、腰痛疼痛视觉模拟量表(VAS)评分及Oswestry功能障碍指数(ODI),评价手术疗效。结果所有患者手术均顺利完成,随访 6个月。过屈跪位组L4/L5椎板间隙高度大于俯卧位组,差异有统计学意义(P 0.05);2组L4/L5椎板间隙宽度差异无显著统计学意义(P 0.05)。所有患者术后下肢痛和腰痛明显缓解,所有患者下肢痛、腰痛VAS评分及ODI均较术前显著改善。结论患者在过屈跪位下可显著减小腰椎曲度、增加椎板间隙高度,使经皮内窥镜系统工作通道在椎管内的活动度及安全操作空间增加,减少椎板骨质切除。过屈跪位下行PEID治疗L4/L5 LDH安全、有效。     

基于CT HU值的单节段腰椎间盘突出症患者腰椎椎体骨密度分布的研究

目的 探讨单节段腰椎间盘突出症患者腰椎椎体之间和椎体内不同区域骨密度的分布特点及其临床意义。方法 回顾性研究。纳入2013年1月—2020年12月在河北医科大学第三医院脊柱外科单节段腰椎间盘突出症患者100例,其中男、女各50例,年龄21~69岁。100例患者按年龄分为21~30岁、31~40岁、41~50岁、51~60岁、61~70岁5个年龄组,均接受腰椎后路减压椎间融合术治疗。在L₁~S₁椎体CT正中矢状位影像选择松质骨范围最大的区域测量其HU值,进而将L_1~5椎体自上而下三等分,分别测量每一等份内松质骨的HU值;基于腰椎MRI,采用Pfirrmann分级标准评估椎间盘退变程度。对比5组患者基线资料;比较不同年龄组间及同一年龄组内L_1~5不同椎体间的松质骨HU值,分析同一腰椎节段上、中、下不同区域椎体松质骨HU值;观察不同Pfirrmann分级的腰椎间盘上位与下位椎体松质骨HU值的变化趋势。结果 各年龄组间患者的性别分布、体质量指数、病变节段、术前腰椎侧凸角等基线资料比较,差异均无统计学意义（P值均>0.05）。骨密度HU值在L_1~5各椎体之间并未表现出梯度差异,随着年龄增长L_1~5椎体HU值表现出下降趋势。L_1~5椎体内部存在骨密度梯度变化,上、中、下1/3椎体松质骨HU值依序增大,但差异均无统计学意义（P值均>0.05）。100例500个椎间盘中,Pfirrmann分级Ⅰ级4例、Ⅱ级204例、Ⅲ级186例、Ⅳ级93例、Ⅴ级13例;上位椎体和下位椎体松质骨HU值随着椎间盘退变分级的升高而减小,而上、下位椎体松质HU值差值则逐渐增大,差异均有统计学意义（F=21.46、5.25、20.39,P值均<0.01）。结论 单节段腰椎间盘突出症患者腰椎不同椎体之间骨密度无梯度差异,而各腰椎椎体内部骨密度HU值表现出从头端向尾端增加的趋势。骨密度下降以及上下相邻椎体松质骨骨密度梯度的较大差值对于椎间盘退变可能具有病因学意义。     

Three Hundred and Fifty-Three Consecutive Patients with Permanent Transvenous Pacemakers

The safety and convenience of the tronsvenous approach to long-term endocardial pacing are well established, but its principal drawback is electrode displacement. The reported incidence of this complication varies between 3.0% fo 36.7%, and is highest in the early post-implantation period before endocardiaL fixation of the electrode tip. Recently Brewster and Evans determined that the electrode displacement rate in 21 published series averaged 14.3% However, the Inter Society Committee on Heart Diseases (ICHD) report on pacemakers states that a rate of early displacement greater than 5% calls for a critical review of results. The training and expertise of the persons inserting the pacemaker electrodes undoubtedly are major factors which determine the proper transvenous placement of permanent cardiac electrodes. This paper deals with our clinical experience of 353 patients who received permanent transvenous peacemakers during the period September 1, 1974 through March 1. 1979 with emphasis on problems and complications encountered and overall results.     

巨大型腰椎椎间盘突出症的外科治疗

目的：探讨巨大型腰椎椎间盘突出症的发病特点及手术疗效。方法回顾分析5年来手术治疗的腰椎椎间盘突出症患者共1441例,将其分为巨大型172例、普通型1269例,随访记录其发病年龄、性别、症状特点、突出形态、手术方式、手术并发症、术后疗效、术后复发率等,并行统计学对比分析2组在各方面的异同。结果1441例患者资料完整,总体男女比2．99∶1,平均年龄43．4岁。2组之间比较：平均年龄2组之间差异无统计学意义（ P＞0．05）;性别比例均为男性好发,巨大型组男女比明显低于普通型组（P＜0．05）;平均病程巨大型组明显短于普通型组（P＜0．05）;巨大型组与普通型组相比,双侧症状更多、肌力下降者更多、马尾综合征更多、中央型比例更高、椎间盘脱出者更多（P＜0．01）;巨大型组中实施双侧减压明显高于普通型组（P＜0．01）;手术并发症发生率,包括术中脑脊液漏发生率、切口感染率、深部感染率2组之间差异无统计学意义（P＞0．05）;手术优良率分别为94．12％、93．78％,2组之间差异无统计学意义（P＞0．05）;术后复发率巨大型组明显低于普通型组（P＜0．05）。结论巨大型腰椎椎间盘突出症与普通型相比有截然不同的临床特点,其手术治疗可达到等同于普通型的良好疗效,术后复发率低于普通型腰椎椎间盘突出症。     

Hip displacement in relation to age and gross motor function in children with cerebral palsy

Purpose

Hip dislocation in cerebral palsy (CP) is a serious complication. By radiographic screening and prophylactic surgery of children at risk most dislocations can be prevented. CPUP, the Swedish CP registry and follow-up program, includes annual radiographic examinations of children at Gross Motor Function Classification System (GMFCS) levels III–V. Data from CPUP were analysed to assess the risk of hip displacement in relation to GMFCS levels and age.

Methods

All children at GMFCS levels III–V (N = 353) whose first radiographic screening occurred before 3 years of age were followed between the ages 2–7 years. Migration percentages (MPs) were recorded annually (1,664 pelvic radiographs) and analysed using discrete time survival analysis.

Results

The risk of hip displacement between 2 years and 7 years of age was significantly (p < 0.05) higher for children at GMFCS level V during the entire study period. The risk was highest at 2–3 years of age and decreased significantly (p < 0.001) with each year of age (OR = 0.71, 95 % CI 0.60–0.83). The cumulative risk at age 7 years for those at GMFCS V for MP ≥ 40 % was 47 % (95 % CI 37–58). The corresponding risk at GMFCS IV was 24 % (16–34) and at GMFCS III 23 % (12–42).

Conclusions

Children at GMFCS V have a significantly higher risk of hip displacement compared with children at GMFCS III–IV. The risk is highest at 2–3 years of age. The results support a surveillance program including radiographic hip examinations as soon as the diagnosis of severe CP is suspected.