纤维桩树脂核用于老年残根残冠修复的效果及对生活质量的影响

目的:探讨老年残根残冠应用纤维桩树脂核修复的临床效果及对病人生活质量的影响。方法:抽选我院行纤维桩树脂核修复的79例(86颗)老年残根残冠患者,对其进行3年随访,观察总体及不同牙位修复成功率和修复前、后生活质量的变化。结果:修复后进行3年随访,86颗残根残冠修复总成功率为95.3%,不同牙位修复成功率无显著差异(P0.05),均在94%以上,86颗牙失败4颗(其中2颗并发牙周炎、2颗牙纤维桩脱落,均未出现牙桩折断);修复后患者生活质量总分及各维度评分均明显优于修复前(P0.05)。结论:纤维桩树脂核是一种极为理想的残冠残根修复材料,能显著提高老年患者术后的生活质量,值得临床推广。     

桩—核—冠系列对牙体大面积缺损修复的应用

牙体严重缺损,牙髓不可避免受累,要先作根管治疗然后再根据形态和功能的要求进行牙体修复。60年代以来许多学者开始使用成品牙本质固位钉加银汞或复合树脂修复体修复大面积缺损的牙齿。由于死髓牙本质脱水弹性和张力强度降低,容易引起牙折,常导致修复失败。70年代根管桩加银汞修复体十分盛行,但此种设计远期效果不理想,往往易引起牙根折裂,Sorenser指出经根管治疗的上下后牙未作冠复盖的临床成功率只有50％左右,而作冠复盖的临床成功率达90％以上。因此,经根管治疗的牙齿,大多数临床牙冠缺损严重,用冠类修复能获得较好效果。而桩和核心制作为冠修复打下基础。桩、核可给修复体提供垂直与水平向的支持与固位。桩、核套上全冠修复体,使患牙具有更大防裂能力,同时增加冠外抗力和咬合力的保护,并可预防根面龋。在桩、核上可根据患者条件和需要制作任何一种全冠修复体。目前随着修复材料不断改革提高,对残冠残根的修复带来美好前景。我们对牙体严重缺损保存治疗中桩核的应用作了一些探索,在临床上我们对50多只牙冠大面积缺损的牙齿应用桩核冠系列修复获得了较好效果。     

玻璃纤维桩树脂核和金属铸造桩核修复上颌前牙残根残冠的疗效比较

目的:比较玻璃纤维桩树脂核和金属铸造桩核修复上颌前牙残根残冠的临床疗效。方法:选择2008年1月-2011年12月我院200例上颌前牙残根残冠患者,随机分为观察组与对照组,每组100例,观察组采用玻璃纤维桩树脂核修复,对照组采用金属铸造桩核修复,比较两组患者患齿修复成功率、修复后1、2年咀嚼效能有效率、修复前后患齿健康指数。结果:1观察组患者因牙龈炎、牙龈着色、冠折/根折、全冠松动/脱落、桩核松动/脱落而失败的发生率为2.0%、2.0%、1.0%、2.0%、1.0%,均低于对照组的6.0%、7.0%、5.0%、7.0%、5.0%,观察组总成功率为94.0%,显著高于对照的74.0%,两组数据比较差异均有统计学意义(均P0.05);2观察组修复后1、2年咀嚼功能改善有效率分别为94.0%、86.0%,对照组分别为89.0%、72.0%,比较差异均有统计学意义(均P0.05);3两组患者修复后抗折裂强度、GI、SBI均较修复前明显改善,比较差异有统计学意义(均P0.05),观察组修复后抗折裂强度、GI、SBI较对照组改善更明显,比较差异有统计学意义(均P0.05)。结论:玻璃纤维桩树脂核修复上颌前牙残根残冠具有较高成功率,咀嚼功能改善明显,临床效果优于金属铸造桩核修复。     

不同桩核在残根残冠修复中的疗效比较

目的:观察成品螺纹桩、铸造钴铬合金桩核、纤维桩修复残根残冠的临床应用效果.方法:将90例患者90颗残根残冠,随机分成3组,分别采用A组成品螺纹桩,B组铸造钴铬合金桩核,C组纤维桩进行修复,并随诊18个月后,比较3组患者治疗后的成功率.结果:3组患者经过治疗后,成品螺纹桩组的成功率为73.33％,铸造钴铬合金桩核组的成功率为60.00％,纤维桩组的成功率为96.67％,三组差异有统计学意义(P＜0.005).结论:与成品螺纹桩和铸造钴铬合金桩核相比,纤维桩具有更好的粘结性及抗折能力.     

不同粘接剂在纤维桩修复上前牙残冠残根中的临床疗效比较

目的:比较2种不同的纤维桩粘接剂在桩-核-冠修复方法修复前牙残冠残根的临床疗效.方法:对近2年内的78名96例经过完善根管治疗的上前牙残冠、残根的患者,选用2种不同的粘接材料(3M ESPE RelyX Unicem粘接剂和Panavia F粘接剂)对PD(Produits Dentaires SA)纤维桩进行粘接、3M ESPE Kiltek Z350树脂等材料修复,并经过2年的随访观察,评估2种治疗方法的疗效.结果:经过2年的随访调查发现,96例患牙中仅在半年时出现了1例修复体折断(使用Panavia F粘接法),其余95例均未出现纤维桩的松动、脱落,无根折、桩折现象.结论:纤维桩修复残冠、残根是一种操作简便、省时、临床疗效好的修复方法;3Municem和PanaviaF粘接剂均可以有效防止纤维桩在修复上前牙残冠、残根中的松动、脱落现象,均是有效的粘接手段.     

不同桩核修复上颌前牙残根残冠的疗效比较

目的:对比玻璃纤维桩树脂核与铸造金属桩核修复上颌前牙残根残冠的疗效。方法:选取2011年10月至2013年12月在我院口腔科就诊的120例因前牙牙体缺损或者冠折需行桩核冠修复术的患者,随机分为玻璃纤维桩组及铸造金属桩组,每组各60例。玻璃纤维桩组采取玻璃纤维桩核与烤瓷全冠修复术治疗,铸造金属桩组采取钴铬合金铸造桩核与烤瓷全冠修复术治疗。对比2组患者修复治疗的疗效及失败情况。结果:玻璃纤维桩组有1例(1颗)患者因搬迁失访,铸造金属桩组有2例(2颗)患者因金属致敏性导致治疗中断;余117例(179颗)患者中,玻璃纤维桩组共92颗牙,成功率为89.13%,铸造金属桩组共87颗牙,成功率为79.31%,玻璃纤维桩组的明显高于铸造金属桩组;玻璃纤维桩组牙根折裂、桩核松动或脱落的发生率明显低于铸造金属桩组;而桩核折的发生率则明显高于铸造金属桩组,差异有统计学意义(P0.05)。结论:玻璃纤维桩具有美观、抗疲劳、易于操作、患者复诊次数少等优势,且不存在细胞毒性及过敏反应等问题,其修复效果优于铸造金属桩核。     

纤维桩树脂核修复老年残根残冠的疗效及对炎性因子的影响

目的:探讨纤维桩树脂核修复老年残根残冠的疗效及对炎性因子的影响。方法:抽取2012年1月至2013年4月期间行老年残根残冠修复的患者80例,共92颗患牙,按随机数字表法分为研究组和对照组各40例,其中研究组患牙47颗,采用纤维桩树脂核修复;对照组患牙45颗,采用金属铸造桩核修复。收集两组患者的血清和龈沟液样本,采用酶联免疫吸附法(Enzyme-Linked Immunosorbnent Assay,ELISA)分别检测两组的IL-8、IL-6及TNF-α水平。对比两组疗效及炎性因子水平。结果:研究组治疗患牙总体成功率明显高于对照组,失败率明显低于对照组(P0.05);研究组不同牙位的治疗成功率均较对照组高,但差异不明显(P0.05);修复前两组的IL-8、IL-6及TNF-α的水平差异不明显;研究组修复后1周、1个月及1年的IL-8和IL-6水平均明显低于对照组(P0.05),研究组修复后1年的TNF-α水平明显低于对照组(P0.05),两组患者修复后1周和修复后1月的TNF-α水平相差不大(P0.05);重复测量方差分析结果显示,两组IL-8、IL-6及TNF-α的水平均随着修复时间的延长而降低(P0.05)。结论:纤维桩树脂核修复老年残根残冠具有更好的疗效,对降低牙龈沟液中炎性因子水平的作用明显,值得在临床上应用和推广。     

放射直视影像在口腔固定修复中的临床应用评价

目的：探讨放射直视影像（radiovisiography,RVG）在口腔固定修复中的应用价值。方法：对拟行口腔固定修复中的全冠及桩核冠修复的患牙术前进行RVG投照,对RVG图像进行分析,分别测量牙冠各部位的厚度以及牙根的长度、角度、根管各部位的直径,从而对活髓牙牙体预备中并发症的预测和预防以及桩间隙制备时器械的选择和桩的设计。结果：67颗活髓牙中7例前牙需要术前进行根管治疗,1例术中发生针尖大小的穿髓点,予dycal垫底后保留活髓。因为术前及早的预测穿髓事件的发生,病人均满意及理解。拟行桩核冠修复的21颗患牙无一例发生根管侧穿,观察3月未发现有一例根折。结论：RVG能快速,经济,直观的给临床口腔修复医师提供牙体全面的信息,有利于并发症的预防及治疗方案的选择。     

金属桩与玻璃纤维桩对老年上颌前牙残根残冠修复的临床疗效比较

目的:探讨金属桩与玻璃纤维桩对老年上颌前牙残根残冠修复的临床疗效。方法:收集我院口腔科收治的上颌前牙残根残冠修复患者40例,随机分为玻璃纤维桩组和金属桩组,每组各20例,玻璃纤维桩组患者给予玻璃纤维桩进行残根残冠修复,金属桩组给予金属桩进行残根残冠修复,治疗结束后1年随访,对所有患者的牙龈指数(GI)、修复齿出血指数(SBI)、不良反应发生率、患者修复效果以及患者疗效进行检测并比较。结果:与治疗前相比,两组患者的牙龈指数(GI)以及修复齿出血指数(SBI)均下降(P0.05);与金属桩组相比,玻璃纤维桩组患者的牙龈指数(GI)以及修复齿出血指数(SBI)较低(P0.05),不良反应发生率较低(P0.05),颜色匹配率以及边缘适合率较高(P0.05),两组患者修复体完整例数百分率比较无明显差异(P0.05),玻璃纤维桩组患者的治疗成功率较高(P0.05)。结论:玻璃纤维桩在老年上颌前牙残根残冠修复的应用与金属桩组相比临床效果较好。     

牙体大面积缺损修复中玻璃纤维桩与双固化桩核材料联合制作桩核的应用

为探讨牙体大面积缺损修复对玻璃纤维桩与双固化桩核材料联合制作桩核的应用效果,回顾性分析本院2011年2月~2012年2月收治的170例(229颗牙)大面积牙体缺损患者的临床资料,均实施桩核修复治疗,并按照所使用的材料分为铸造金属桩核组83例(109颗牙)和玻璃纤维桩联合双固化桩核材料组87例(120颗牙)。修复结束后随访36个月,了解两组的修复效果,并进行比较。经随访,玻璃纤维桩联合双固化桩核材料组的修复成功率显著高于铸造金属桩核组,p0.05,对2组患者修复失败的原因进行分析,包括松动脱落、牙龈炎、桩断裂、牙龈着色以及牙根断裂。其中,玻璃纤维桩联合双固化桩核材料组未出现牙龈着色和牙根断裂病例。所有修复失败的病例均接受重新修复,所有牙根均得到保留。表明牙体大面积缺损修复中实施玻璃纤维桩联合双固化桩核材料桩核修复可以获得良好的修复效果。     

家蚕滞育激素-性信息素合成激活肽基因表达的调节

滞育激素和性信息素合成激活肽是两个重要的昆虫神经肽,这两个神经肽由一个基因编码．利用分子杂交和ＲＴ－ＰＣＲ技术,确定了滞育激素－性信息素合成激活肽基因表达的调节不属于转录后的调节,推定为翻译后形成一个大的前体多肽再剪接为几个成熟的神经肽分子．     

Postreproductive lifespans are rare in mammals

A species has a post‐reproductive stage if, like humans, a female entering the adult population can expect to live a substantial proportion of their life after their last reproductive event. However, it is conceptually and statistically challenging to distinguish these true post‐reproductive stages from the usual processes of senescence, which can result in females occasionally surviving past their last reproductive event. Hence, despite considerable interest, the taxonomic prevalence of post‐reproductive stages remains unclear and debated. In this study we use life tables constructed from published data on wild populations of mammals, and statistical measures of post‐reproductive lifespans, to distinguish true post‐reproductive stages from artefacts of senescence and demography in 52 species. We find post‐reproductive stages are rare in mammals and are limited to humans and a few species of toothed whales. By resolving this long‐standing debate, we hope to provide clarity for researchers in the field of evolutionary biology and a solid foundation for further studies investigating the evolution and adaptive significance of this unusual life history trait.     

转基因植物转录后基因沉默的特点、机理及应用

自在转基因植物中发现转基因沉默现象以来 ,很多学者对该现象进行了广泛的研究 ,认为其作用机制有三种 :位置依赖性基因沉默、转录水平基因沉默、转录后水平基因沉默。目前主要集中于转录后水平基因沉默的研究 ,通过研究发现它具有广泛性、可传导性及特异性的特点 ,并对其机制提出了一些假说。最近 ,人们还发现转录后水平基因沉默与植物抗病毒能力有联系。本文对转基因植物转录后基因沉默的特点、机理及应用方面的进展作了综述     

Post‐fledging survival of altricial birds: ecological determinants and adaptation

For altricial young, fledging is an abrupt step into an unknown environment. Despite increasing numbers of studies addressing the post‐fledging period, our current knowledge of the causes and consequences of post‐fledging survival remains fragmentary. Here, we review the literature on post‐fledging survival of juvenile altricial birds, addressing the following main questions: Is low post‐fledging survival a bottleneck in the altricial reproductive cycle? What is known of proximate and ultimate causal factors such as trophic relations (food and predation), habitat conditions, or abiotic factors acting in the post‐fledging period? We analyzed weekly survival estimates from 123 data series based on studies of 65 species, covering weeks 1–13 post‐fledging. As a general pattern, survival of fledglings was low during the first week post‐fledging (median rate = 0.83), and improved rapidly with time post‐fledging (week 4 median rate = 0.96). For ground‐nesting species, survival immediately after leaving nests was similar to egg‐to‐fledging survival. For species breeding above‐ground, survival during the first week post‐fledging was substantially lower than during both the nestling period and later post‐fledging stages. Thus, the early post‐fledging period is a bottleneck of markedly elevated mortality for most altricial species. Predation was the main proximate cause of mortality. Various factors such as habitat, annual and seasonal variation in the environment, and the physical condition of fledglings have been found to affect post‐fledging survival. Individual survival depended strongly on physical traits such as mass and wing length, which likely influence the ability of fledglings to escape predation. Trophic relationships at various levels are the main ultimate driver of adaptation of traits relevant to survival during the pre‐ and post‐fledging periods. Spatiotemporal dynamics of food resources determine the physical development of juveniles and, in turn, their performance after fledging. However, predators can cause quick and efficient selection for fledgling traits and adult breeding decisions. Parental strategies related to clutch size and timing of breeding, and the age and developmental stage at which young fledge have substantial effects on post‐fledging survival. The intensity and duration of post‐fledging parental investment also influences fledgling survival. Post‐fledging mortality is therefore not a random and inevitable loss. Traits and strategies related to fledging and the post‐fledging stage create large fitness differentials and, therefore, are integral, yet poorly understood, parts of the altricial reproductive strategy.     

Attitudes toward Post‐Trial Access to Medical Interventions: A Review of Academic Literature,Legislation, and International Guidelines

There is currently no international consensus around post‐trial obligations toward research participants, community members, and host countries. This literature review investigates arguments and attitudes toward post‐trial access. The literature review found that academic discussions focused on the rights of research participants, but offered few practical recommendations for addressing or improving current practices. Similarly, there are few regulations or legislation pertaining to post‐trial access. If regulatory changes are necessary, we need to understand the current arguments, legislation, and attitudes towards post‐trial access and participants and community members. Given that clinical trials conducted in low‐income countries will likely continue, there is an urgent need for consideration of post‐trial benefits for participants, communities, and citizens of host countries. While this issue may not be as pressing in countries where participants have access to healthcare and medicines through public schemes, it is particularly important in regions where this may not be available.     

Paternity analyses in wild‐caught and laboratory‐reared Caribbean cricket females reveal the influence of mating environment on post‐copulatory sexual selection

Polyandry is ubiquitous in insects and provides the conditions necessary for male‐ and female‐driven forms of post‐copulatory sexual selection to arise. Populations of Amphiacusta sanctaecrucis exhibit significant divergence in portions of the male genitalia that are inserted directly into the female reproductive tract, suggesting that males may exercise some post‐copulatory control over fertilization success. We examine the potential for male–male and male–female post‐copulatory interactions to influence paternity in wild‐caught females of A. sanctaecrucis and contrast our findings with those obtained from females reared in a high‐density laboratory environment. We find that female A. sanctaecrucis exercise control by mating multiple times (females mount males), but that male–male post‐copulatory interactions may influence paternity success. Moreover, post‐copulatory interactions that affect reproductive success of males are not independent of mating environment: clutches of wild‐caught females exhibit higher sire diversity and lower paternity skew than clutches of laboratory‐reared females. There was no strong evidence for last male precedence in either case. Most attempts at disentangling the contributions of male–male and male–female interactions towards post‐copulatory sexual selection have been undertaken in a laboratory setting and may not capture the full context in which they take place – such as the relationship between premating and post‐mating interactions. Our results reinforce the importance of designing studies that can capture the multifaceted nature of sexual selection for elucidating the role of post‐copulatory sexual selection in driving the evolution of male and female reproductive traits, especially when different components (e.g. precopulatory and post‐copulatory interactions) do not exert independent effects on reproductive outcomes.     

Population level correlation between pre-alighting and post-alighting host plant preference in the Glanville fritillary butterfly

1. In many populations of the Glanville fritillary butterfly Melitaea cinxia, ovipositing females exhibit a post‐alighting preference for one of the potential host plant species available. The work reported here aimed to establish whether females with different post‐alighting preferences can discriminate between their host plant species prior to alighting, and whether pre‐alighting and post‐alighting preferences are correlated at the population level. 2. Alighting and oviposition events were recorded for groups of females from six populations in greenhouse and field experiments. 3. Landing frequencies did not change with experience, indicating that M. cinxia females did not learn from previous encounters with host plants. 4. Females from populations exhibiting post‐alighting preference searched efficiently for their host plants in the sense that they landed mainly on the species on which they oviposited predominantly. Pre‐alighting and post‐alighting preferences were correlated at the population level. 5. The correlation between pre‐alighting and post‐alighting preferences helps to explain why in nature, where the host plants often occur in distinct patches, females are more likely to colonise habitat patches in which their preferred host plant is abundant.     

High and dry: post‐fire tree seedling establishment in subalpine forests decreases with post‐fire drought and large stand‐replacing burn patches

Aim Climate warming and increased wildfire activity are hypothesized to catalyse biogeographical shifts, reducing the resilience of fire‐prone forests world‐wide. Two key mechanisms underpinning hypotheses are: (1) reduced seed availability in large stand‐replacing burn patches, and (2) reduced seedling establishment/survival after post‐fire drought. We tested for regional evidence consistent with these mechanisms in an extensive fire‐prone forest biome by assessing post‐fire tree seedling establishment, a key indicator of forest resilience. Location Subalpine forests, US Rocky Mountains. Methods We analysed post‐fire tree seedling establishment from 184 field plots where stand‐replacing forest fires were followed by varying post‐fire climate conditions. Generalized linear mixed models tested how establishment rates varied with post‐fire drought severity and distance to seed source (among other relevant factors) for tree species with contrasting post‐fire regeneration adaptations. Results Total post‐fire tree seedling establishment (all species combined) declined sharply with greater post‐fire drought severity and with greater distance to seed sources (i.e. the interior of burn patches). Effects varied among key species groups. For conifers that dominate present‐day subalpine forests (Picea engelmannii, Abies lasiocarpa), post‐fire seedling establishment declined sharply with both factors. One exception was serotinous Pinus contorta, which did not vary with either factor. For montane species expected to move upslope under future climate change (Larix occidentalis, Pseudotsuga menziesii, Populus tremuloides) and upper treeline species (Pinus albicaulis), establishment was unrelated to either factor. Greater post‐fire tree seedling establishment on cooler/wetter aspects suggested local topographic refugia during post‐fire droughts. Main conclusions If future drought and wildfire patterns manifest as expected, post‐fire tree seedling establishment of species that currently characterize subalpine forests could be substantially reduced. Compensatory increases from lower montane and upper treeline species may partially offset these reductions, but our data suggest important near‐ to mid‐term shifts in the composition and structure of high‐elevation forests under continued climate warming and increased wildfire activity.     

Evolution of precopulatory and post‐copulatory strategies of inbreeding avoidance and associated polyandry

Inbreeding depression is widely hypothesized to drive adaptive evolution of precopulatory and post‐copulatory mechanisms of inbreeding avoidance, which in turn are hypothesized to affect evolution of polyandry (i.e. female multiple mating). However, surprisingly little theory or modelling critically examines selection for precopulatory or post‐copulatory inbreeding avoidance, or both strategies, given evolutionary constraints and direct costs, or examines how evolution of inbreeding avoidance strategies might feed back to affect evolution of polyandry. Selection for post‐copulatory inbreeding avoidance, but not for precopulatory inbreeding avoidance, requires polyandry, whereas interactions between precopulatory and post‐copulatory inbreeding avoidance might cause functional redundancy (i.e. ‘degeneracy’) potentially generating complex evolutionary dynamics among inbreeding strategies and polyandry. We used individual‐based modelling to quantify evolution of interacting precopulatory and post‐copulatory inbreeding avoidance and associated polyandry given strong inbreeding depression and different evolutionary constraints and direct costs. We found that evolution of post‐copulatory inbreeding avoidance increased selection for initially rare polyandry and that evolution of a costly inbreeding avoidance strategy became negligible over time given a lower‐cost alternative strategy. Further, fixed precopulatory inbreeding avoidance often completely precluded evolution of polyandry and hence post‐copulatory inbreeding avoidance, but fixed post‐copulatory inbreeding avoidance did not preclude evolution of precopulatory inbreeding avoidance. Evolution of inbreeding avoidance phenotypes and associated polyandry is therefore affected by evolutionary feedbacks and degeneracy. All else being equal, evolution of precopulatory inbreeding avoidance and resulting low polyandry is more likely when post‐copulatory inbreeding avoidance is precluded or costly, and evolution of post‐copulatory inbreeding avoidance greatly facilitates evolution of costly polyandry.