Experimental study of the damage characteristics of rocks containing non-penetrating cracks under cyclic loading

The damage evolution process of non-penetrating cracks often causes some unexpected engineering disasters.Gypsum specimens containing non-penetrating crack(s)are used to study the damage evolution and characteristics under cyclic loading.The results show that under cyclic loading,the relationship between the number of non-penetrating crack(s)and the characteristic parameters(cyclic number,peak stress,peak strain,failure stress,and failure strain)of the pre-cracked specimens can be represented by a decreasing linear function.The damage evolution equation is fitted by calibrating the accumulative plastic strain for each cycle,and the damage constitutive equation is proposed by the concept of effective stress.Additionally,non-penetrating cracks are more likely to cause uneven stress distribution,damage accumulation,and local failure of specimen.The local failure can change the stress distribution and relieve the inhibition of non-penetrating crack extension and eventually cause a dramatic destruction of the specimen.Therefore,the evolution process caused by non-penetrating cracks can be regarded as one of the important reasons for inducing rockburst.These results are expected to improve the understanding of the process of spalling formation and rockburst and can be used to analyze the stability of rocks or rock structures.

Characterization of alpine meadow surface crack and its correlation with root-soil properties

Quantifying surface cracks in alpine meadows is a prerequisite and a key aspect in the study of grassland crack development.Crack characterization indices are crucial for the quantitative characterization of complex cracks,serving as vital factors in assessing the degree of cracking and the development morphology.So far,research on evaluating the degree of grassland degradation through crack characterization indices is rare,especially the quantitative analysis of the development of surface cracks in alpine meadows is relatively scarce.Therefore,based on the phenomenon of surface cracking during the degradation of alpine meadows in some regions of the Qinghai-Tibet Plateau,we selected the alpine meadow in the Huangcheng Mongolian Township,Menyuan Hui Autonomous County,Qinghai Province,China as the study area,used unmanned aerial vehicle(UAV)sensing technology to acquire low-altitude images of alpine meadow surface cracks at different degrees of degradation(light,medium,and heavy degradation),and analyzed the representative metrics characterizing the degree of crack development by interpreting the crack length,length density,branch angle,and burrow(rat hole)distribution density and combining them with in situ crack width and depth measurements.Finally,the correlations between the crack characterization indices and the soil and root parameters of sample plots at different degrees of degradation in the study area were analyzed using the grey relation analysis.The results revealed that with the increase of degradation,the physical and chemical properties of soil and the mechanical properties of root-soil composite changed significantly,the vegetation coverage reduced,and the root system aggregated in the surface layer of alpine meadow.As the degree of degradation increased,the fracture morphology developed from"linear"to"dendritic",and eventually to a complex and irregular"polygonal"pattern.The crack length,width,depth,and length density were identified as the crack characterization indices via analysis of variance.The results of grey relation analysis also revealed that the crack length,width,depth,and length density were all highly correlated with root length density,and as the degradation of alpine meadows intensified,the underground biomass increased dramatically,forming a dense layer of grass felt,which has a significant impact on the formation and expansion of cracks.

Root pruning is effective in alleviating the inhibition of soybean growth caused by anaerobic stress for a short period

Soybean is an important upland crop,but its productivity is often limited by anaerobic stress caused by waterlogging.The ability to adjust root growth under environmental constraints is an important physiological trait for adapting to an everchanging environment,and root pruning is an artificial technique for regenerating the root system.In the present study,we investigated whether root pruning in soybean can effectively alleviate the inhibitory effects of anaerobic stress.Soybean plants were affected by anaerobic stress at the germination,vegetative stage 1(V1),and reproductive stage 1(R1)stages,and then the plants were treated with root pruning just after the stress treatment.Soybean plants at the germination stage were treated with root cap and tip removals after hypoxia(N_(2)treatment).Root cap removal was more effective in suppressing the inhibitory effects of hypoxia than root tip removal(5 mm from the tip).The shoot dry weights of the soybean plants with and without root cap removal after hypoxia were 51.2 and 73.8%of the control,respectively,while the root dry weights of plants with and without root cap removal after hypoxia were 43.2 and 62.8%of the control,respectively.As root cap removal effectively enhanced soybean growth after anaerobic stress,the root cap may be the candidate tissue for the stress memory mechanism.When soybean plants at the V1 stage of growth were affected by anaerobic stress,the branch number,pod weight in the main stem,root length,and root surface area of the soybean plants treated with anaerobic stress at the R1 stage significantly decreased compared with those of the control.In contrast,root pruning(2 mm from the tip)immediately after the stress treatment enhanced root growth,branch number,and pod weight.The branch number,pod weight,root length,and root surface area of the plants treated with root pruning were 1.13,1.14,1.12,and 1.13 times higher than those of plants treated with anaerobic stress.Plasmolysis was observed in the root meristem,columella,and cortical cells in soybean roots subjected to anaerobic conditions.However,damage was not observed in the newly emerged roots after root pruning in plants treated with anaerobic stress.These results suggested that root pruning is effective in enhancing soybean growth after anaerobic stress.This effectiveness may be due to the regeneration and elongation of healthy lateral roots during the recovery period.When soybean plants were affected by anaerobic stress at the R1 stage,root pruning just after the stress treatment was ineffective.Thus,suppressing the growth reduction due to anaerobic stress at reproductive stages using only root pruning may be difficult.

iRoot SP辅助单尖充填技术一次性根管治疗牙隐裂伴牙髓炎的临床效果

目的探讨iRoot SP辅助单尖充填技术一次性根管治疗牙隐裂伴牙髓炎的临床效果。方法选取2019年6月至2021年10月于本院就诊的70例(70颗牙)牙隐裂伴牙髓炎患者作为研究对象,采用随机数字表法将其分为对照组与试验组,各35例(35颗牙)。对照组采用常规多次根管治疗结合热牙胶垂直加压充填技术,试验组采用iRoot SP辅助单尖充填技术一次性根管治疗。比较两组的术后24 h疼痛情况、根管充填时间、临床疗效、咬合力、松动度及牙龈指数。结果试验组术后24 h的总疼痛率为5.71%,低于对照组的25.71%,差异具有统计学意义(P<0.05)。试验组的根管充填时间短于对照组,差异具有统计学意义(P<0.05)。两组的治疗总有效率比较,差异无统计学意义(P>0.05)。治疗后7 d,两组的咬合力均升高,松动度及牙龈指数评分均降低,差异具有统计学意义(P<0.05);治疗后7 d,试验组的咬合力高于对照组,牙龈指数评分低于对照组,差异具有统计学意义(P<0.05)。结论iRoot SP辅助单尖充填技术一次性根管治疗牙隐裂伴牙髓炎的临床效果较好,可缩短根管填充时间,减轻术后疼痛程度,改善牙齿咬合力、松动度及牙龈指数。

预制裂纹的预备后椭圆形根管牙根有限元模型构建及分析

目的分析椭圆形根管牙根两种预备形态下,根管壁微裂纹对牙根受力的影响。方法选择椭圆形根管的前磨牙20颗,器械扩大预备根管、制造微裂纹并染色,切片后显微镜下观察牙本质微裂纹的产生及分布。据此构建两种预备形态下预制裂纹的牙根模型,评估受力时微裂纹处及牙根的应力分布。结果椭圆形根管牙根的微裂纹总是出现在颊舌侧,由根管壁向牙根表面扩展,与有限元分析所展示的应力集中在根管壁颊舌侧的规律一致。微裂纹使根管壁的应力集中点向裂纹尖端处转移,且在尖端极小区域内出现近5倍的应力剧增,使微裂纹极易沿尖端方向扩展,尤其在牙体长轴方向。结论微裂纹的存在不改变椭圆形根管牙根颊舌侧应力集中的特点,但微裂纹的产生使其尖端极小区域内出现剧增的应力集中,这可能是微裂纹迅速扩展为牙根纵裂的机制,临床操作需提高警惕。

齿根裂纹扩展对轮齿时变啮合刚度变化关系的分析

针对齿根裂纹扩展与时变啮合刚度的理论值与实际值偏差较大的问题,该文基于能量法对传统的时变啮合刚度模型进行优化,以获得理论时变啮合刚度的变化规律与实际情况接近。在传统理论时变啮合刚度理论模型的基础上,考虑轮齿的Hertz接触刚度、径向压缩刚度、轮齿的弯曲刚度和轮齿的剪切刚度,以及轮体的柔性变形量等因素,对传统的理论刚度模型进行改进。再采用能量法计算,验证改进的理论模型对健康轮齿、齿根裂纹扩展程度和裂纹扩展角度这3种不同状态下,获得轮齿时变啮合刚度的变化规律。研究结果表明,经改进后的理论刚度模型,计算得出时变啮合刚度变化规律的一致性较好。并且,得出时变啮合刚度值的大小,随着齿根裂纹故障严重程度的增大而减小,随着齿根裂纹扩展角度增大而增大。

裂纹故障下细高齿齿轮齿根动应变研究

为探究裂纹故障对细高齿齿轮齿根动应变的影响规律,采用集中质量法建立齿轮系统动力学模型,将故障下的时变啮合刚度作为输入,对系统动力学方程进行求解得到不同裂纹深度下的齿轮副动态啮合力。利用有限元法建立含裂纹故障齿轮结构动力学分析模型,结合轮齿承载接触分析确定裂纹故障下的齿间载荷分配关系,采用瞬态分析得到齿根应变时域历程,并对不同裂纹深度下的齿根动应变进行分析。仿真结果表明,当从动轮发生裂纹故障后,其齿根动应变故障特征主要表现为啮合区内齿根应变数值的变化,主动轮齿根动应变故障特征主要表现为齿根应变时域历程中出现周期性冲击及幅值衰减,在1.5 mm裂纹深度下主动轮齿根应变峰值因子相对变化量达到12.72%。

裂纹故障下的行星轮系唯象建模及其故障诊断

故障机制是故障诊断的基础,动态建模是研究故障机制的重要手段。现有的行星轮系动态建模主要包括动力学建模和唯象建模两方面。动力学建模难度大,且更多关注单个零部件的动力学特性;唯象建模则从宏观层面对系统特性进行描述。因此,建立行星轮系振动唯象模型,对行星轮系故障机制研究大有裨益。齿根裂纹是行星轮系中常见的故障类型之一。为此,建立了行星轮系正常与裂纹故障下的振动唯象模型,基于冲击动力学理论,计算了轮齿进入啮合时的啮合冲击力及其对动载因数的影响;在此基础上,建立了考虑啮合冲击影响的行星轮系振动唯象模型,得到了正常、太阳轮裂纹、行星轮裂纹等不同健康状态下的振动唯象模型响应;采用均方根、峭度等统计指标对模型响应进行分析,对比了各项统计指标在反映裂纹故障状态时的敏感性。结果表明,峭度可以作为有效反映行星轮系裂纹故障的指标之一。

热牙胶充填法与冷侧方加压法在牙隐裂伴牙髓病变根管治疗中的应用效果对比

目的:对比热牙胶充填法与冷侧方加压法在牙隐裂伴牙髓病变根管治疗中的应用效果。方法:选取2019年1月—2023年12月靖江市人民医院收治的牙隐裂伴牙髓病变患者80例为研究对象,采用随机数字表法分为对照组和研究组,各40例。两组均实施根管治疗,对照组采用冷侧方加压法进行根管充填,研究组采用热牙胶充填法进行根管充填。比较两组治疗总有效率、治疗满意度、咀嚼功能、牙周状况、生活质量。结果:研究组治疗总有效率高于对照组,差异有统计学意义(P=0.034);研究组治疗满意度高于对照组,差异有统计学意义(P=0.034);治疗后,两组咀嚼效率和咀嚼测试吸光度值高于治疗前,研究组高于对照组,差异有统计学意义(P<0.05);治疗后,两组菌斑指数、软垢指数、牙龈出血指数、牙周探诊深度低于治疗前,研究组低于对照组,差异有统计学意义(P<0.05);治疗后,两组世界卫生组织生活质量测定简表评分高于治疗前,研究组高于对照组,差异有统计学意义(P<0.05)。结论:在牙隐裂伴牙髓病变患者根管治疗中,应用热牙胶充填法进行根管充填的效果优于冷侧方加压法,有助于改善患者的咀嚼功能和牙周状况,提高生活质量及满意度。

根管预备、充填及纤维桩的预备对根管壁微裂产生的影响

目的研究根管预备、充填及纤维桩预备对根管壁微裂产生的影响。方法收集150颗离体前磨牙,并随机分为四个大组[1组(n=10)、2组(n=20)、3组(n=40)、4组(n=80)]及15个小组(1组,2组25#、2组40#,3组A25#、3组B25#、3组A40#、3组B40#,4组AX25#、4组AX40#、4组AT25#、4组AT40#、4组BX25#、4组BX40#、4组BT25#、4组BT40#,n=10)。1组:即对照组,不进行预备;2组:均分为两组,一组预备至WaveOne25#,另一组预备则预备至40#;3组:将样本与2组一样进行分组预备,之后进一步分为2个小组,进行冷牙胶侧压充填(A)及热牙胶连续波充填(B);4组:将样本与3组一样进行分组预备及充填,之后将不同方法充填后的样本进一步分为2小组进行RelyXTM(X)和RTD(T)纤维桩预备。将所有的样本从距离根尖3、5、7 mm处垂直于牙体长轴截断,在显微镜下观察微裂发生情况,并进行比较分析。结果1组及2组中均并未有裂纹存在。充填后,3组A与3组B的裂纹数目比较差异无统计学意义(P>0.05)。置入纤维桩后,4组A的牙本质裂纹明显较4组B多,且差异具有统计学意义(22/120 VS 10/120,P<0.05)。在与根尖距离7 mm处,相较于RelyXTM纤维桩,RTD纤维桩预备后牙本质产生更多裂纹,差异具有统计学意义(9/120 VS 23/120,P<0.05)。4组的裂纹总发生率高于1组、2组、3组(P<0.05),说明纤维桩置入后,牙本质裂纹较仅进行牙体预备和充填明显增多。结论纤维桩的预备主要导致根管壁裂纹的产生,冷侧压充填后进行纤维桩预备比热牙胶充填后进行桩体预备更容易产生根管壁裂纹。

不同根管治疗牙隐裂伴牙髓病变患者的临床疗效分析

目的对比不同根管治疗对牙隐裂伴牙髓病患者的效果差异。方法93例牙隐裂伴牙髓病变患者,采用随机方法分为观察组(46例)与对照组(47例)。对照组采用多次根管治疗,观察组采用单次根管治疗。比较两组患者临床疗效以及治疗前后的疼痛评分、出血指数、牙龈指数、咬合力。结果观察组临床总有效率95.65%高于对照组的82.98%(P<0.05)。治疗后,观察组疼痛评分(1.15±0.21)分、出血指数(0.26±0.05)、牙龈指数(0.34±0.06)均低于对照组的(1.55±0.29)分、(0.45±0.08)、(0.47±0.09),咬合力(133.03±24.85)Ibs高于对照组的(118.64±22.01)Ibs,差异有统计学意义(P<0.05)。结论相比多次根管治疗而言,单次根管治疗牙隐裂伴牙髓病的疗效更好,可以减轻治疗后的疼痛,改善患者的牙齿出血指数和牙龈指数,提升咬合力,值得推荐。

正交异性钢桥面板焊接接头疲劳性能提升方法及其评估

为研究顶板厚度、熔透率和焊缝尺寸三种措施对接头疲劳性能是否有所提升,基于ANSYS-FRANC3D联合仿真方法,考虑不同荷载形式和不同裂纹扩展阶段的影响,从而综合评估三种措施对焊接接头疲劳性能的提升效果。研究得知:竖向荷载作用时,仅增加顶板厚度可以改善焊根处开裂情况,短裂纹阶段和长裂纹阶段随着顶板厚增加应力强度因子降幅分别可达30.57%和28.54%,同时也可改善多失效模式下焊根处疲劳开裂情况;水平荷载作用时,仅增加熔透率可改善焊根处疲劳开裂情况;相较于单一失效模式,短裂纹阶段和长裂纹阶段裂纹在多失效模式下,裂纹开裂机率分别提升7.58%和8.93%。

电加热元件套管角焊缝工艺改进研究

稳压器电加热元件套管焊接问题一直以来困扰着各大核设备制造厂。本文提出了套管角焊缝结构下焊接工艺改进措施,并通过焊接数值模拟方法进行了模拟分析,改进了稳压器电加热元件套管角焊缝结构焊接工艺,解决了根部焊接裂纹问题,减小了焊接变形。为打破国外材料技术封锁、加快电加热元件材料国产化提供有力支持。

Effect of Weld Parameters on Effective Notch Stress at Weld Root and Toe of Load Carrying Cruciform Joints

Cruciform joints in ships are prone to fatigue damage and the determination of type of weld plays a significant role in thefatigue design of the joint. In this paper, the effect of weld geometry on fatigue failure of load carrying cruciform joints inships is investigated using Effective Notch Stress (ENS) approach. A fictitious notch of 1 mm radius is introduced at theweld root and toe and fatigue stress is evaluated. The effect of weld leg length (l) and weld penetration depth (p) on ENS atweld root and toe are determined. The critical weld leg length (lcr) at which fatigue failure transitions from weld root toweld toe is investigated. An approximation formula for determination of the critical weld leg length considering weldpenetration depth (p) is proposed.

Involvement of Root Hair during <i>Rhizobial</i>Invasion in Cultivated Peanut (<i>Arachis hypogaea</i>L.)

Peanut root invasion by Bradyrhizobia is through a crack entry, which is different from many other legumes applying an infection thread entry in root hair. Understanding the role of root hair in the crack entry of Bradyrhizobia invasion of peanut root and subsequent peanut nodulation would facilitate improvement of biological nitrogen fixation in cultivated peanut. The objective of this study was to investigate the involvement of root hair in Bradyrhizobial invasion of peanut. Seedling roots of a nodulating peanut cultivar were observed for root hair emergence, its life span, and nodule formation at the base of the lateral roots with and without rhizobia inoculation for 14 days after germination (DAG). Scanning electron microscopy (SEM) was utilized to observe rhizobia accumulation at lateral roots at 24 hours after inoculation (HAI) before the emergence of root hair. Root hair emerged at 7 DAG with or without rhizobia inoculation. Two variations of rosette hair (RoH) were observed, the transient-thin RoH had life span of 3 days after root hair emergence and the thick and densely distributed RoH type stayed till the time of nodule emergence (9 days after inoculation). The lateral root devoid of root hair at the top 2 cm region was found to produce nodules. The SEM observation of seedling roots at 24 HAI showed that Bradyrhizobia invaded the roots at epidermis, protoplasm of cortical cell, and cortical cells of the main root near the newly emerged lateral root in the absence of RoH. The observations validated that root hair is not required in the Bradyrhizobia invasion of peanut root in the crack entry mode. Results from this study provided important morphological information for the hypothesis of close relationship between RoH and peanut nodulation for further genetic study of crack entry mechanism and signaling pathway of symbiosis between Bradyrhizobia and peanut.

根管治疗联合全冠修复治疗牙隐裂的效果分析

目的:探讨牙隐裂患者实施根管治疗联合全冠修复治疗的效果。方法:选取2020年8月—2022年8月临沂市兰山区人民医院收治的84例牙隐裂患者作为研究对象,采用随机数字表法分为观察组与对照组,各42例。对照组给予高嵌体根管治疗,观察组给予根管治疗联合全冠修复。比较两组治疗效果、咬合功能、咀嚼功能及并发症发生情况。结果:观察组治疗总有效率高于对照组,差异有统计学意义(P=0.048)。治疗后,两组最大咬合接触面积、最大咬合力大于治疗前,且观察组大于对照组,两组咬合力不对称指数小于治疗前,且观察组小于对照组,差异有统计学意义(P<0.05);两组龈沟出血指数、牙龈指数低于治疗前,且观察组低于对照组,两组咀嚼效率高于治疗前,且观察组高于对照组,差异有统计学意义(P<0.05)。观察组并发症总发生率低于对照组,差异有统计学意义(P=0.026)。结论:根管治疗联合全冠修复治疗牙隐裂的效果良好,可改善患者咬合功能与咀嚼功能,降低并发症发生率。

考虑裂纹与磨损故障的齿轮传动系统动态特性分析

针对齿轮系统中同时出现裂纹与磨损故障时实现复合故障诊断较为困难的问题,提出了考虑齿廓磨损和齿根裂纹故障的齿轮传动系统动态特性分析模型。首先,基于Archard公式,建立齿轮传动系统磨损数值仿真模型,求解不同磨损周期下的齿廓磨损量;然后,通过势能法建立裂纹及磨损作用下的单齿啮合刚度计算模型,在双齿接触区考虑啮合齿对磨损量间的关系,结合变形协调,建立双齿啮合刚度计算模型;最后,采用集中质量法建立齿轮系统4自由度动力学模型,以含故障的时变啮合刚度为输入,使用Newmark-β法对动态响应进行求解,获得不同程度裂纹与磨损作用下的齿轮动态特性。实验结果表明:该模型能够较好反应复合故障中磨损与裂纹特征;与未考虑磨损后双齿区实际变形的裂纹与磨损复合故障模型相比,该复合故障模型双齿区刚度计算准确性提高了约22%,所提模型可为含磨损与裂纹的齿轮传动系统故障诊断提供有效的动力学补充。

不同治疗方法在隐裂牙中的回顾性分析

目的通过回顾性分析隐裂牙的临床资料,描述隐裂牙的分布情况,采取不同治疗方法后患牙5年有效率的分析,为隐裂牙的临床治疗提供参考。方法选取保定市第一中心医院口腔科2015年1月至2016年12月收治的141例隐裂牙作为研究对象,回顾性分析患者的临床资料、治疗方法以及治疗效果。结果患者的平均年龄为(47.61±11.82)岁。上颌磨牙隐裂发生率较高,为53.19%;裂纹常见于远中隐裂纹,为37.59%。69例隐裂纹深达髓腔的隐裂牙,采取根管治疗,5年有效率为85.51%,其中55例进行全冠修复,5年有效率为92.73%;14例未行全冠修复,5年有效率为57.14%。72例隐裂纹未达髓腔的隐裂牙,55例采取充填治疗,5年有效率为92.73%;17例采取降[牙合]治疗,5年有效率为70.59%。结论对于隐裂纹未达髓腔的隐裂牙,与降相比,采取充填治疗的隐裂牙5年有效率相对较高。对于隐裂纹深达髓腔的隐裂牙,建议采取根管治疗结合全冠修复。

应用故障特征指标相对比值的低转速下编码器信号太阳轮故障特征提取

针对低转速下太阳轮齿根裂纹故障编码器信号特征阶次提取困难的问题,本文提出了一种基于故障特征指标相对比值的特征提取检测方法。首先,将获得的编码器信号通过向前差分处理成瞬时角速度(IAS)信号,按照1/3-二叉树对得到的IAS信号进行子频带划分;其次,对各窄带信号进行包络分析,分别求取正常和故障状态下的IAS信号各子频带的谐波显著性指标(HSI),由此可计算得到其相对比值r;再次,利用r值选取包含故障信息丰富的频带;最后,对处理后的信号在选择的子频带处进行带通滤波,并在提取包络后进行谱分析,提取故障特征。对太阳轮齿根裂纹故障的实测编码器信号进行分析,验证了该方法能有效提取太阳轮故障的特征。

全瓷冠+Cortisomol糊剂根管充填对隐裂性牙髓炎的临床疗效

目的 分析全瓷冠+Cortisomol糊剂根管充填治疗隐裂性牙髓炎者的效果。方法 选取2020年7月至2021年8月接收的隐裂性牙髓炎患者94例作为研究对象,依据随机数字表法分为两组,每组47例。两组均行Cortisomol糊剂根管充填,研究组加用全瓷冠修复,对照组加用金属冠修复,统计对比两组术后3 d疼痛度[视觉模拟量表(visual analog scale, VAS)]、龈沟液内炎性因子[前列腺素E2(prostaglandin E2, PGE2)、一氧化氮(nitric oxide, NO)、白细胞介素-1β(interleukin-1β,IL-1β)]水平以及术后6个月治疗效果、修复满意度、牙周状况[牙齿松动度(tooth mobility, TM)、龈沟出血指数(sulcus bleeding index, SBI)]、咀嚼状况[咀嚼效能、咬合力]。结果 随访6个月,研究组总有效率95.74%,高于对照组72.34%(P<0.05);术后3 d两组VAS评分低于术前,研究组低于对照组(P<0.05);术后3 d两组SBI、TM低于术前,研究组低于对照组(P<0.05);术后3个月两组咬合力、咀嚼效能高于术前,研究组高于对照组(P<0.05);术后3 d两组龈沟液内PGE2、NO、IL-1β水平高于术前,研究组低于对照组(P<0.05);随访6个月,研究组总修复满意度97.87%,高于对照组76.60%(P<0.05)。结论 全瓷冠+Cortisomol糊剂根管充填治疗隐裂性牙髓炎患者效果明显,可减轻疼痛程度,改善牙周状况与咀嚼状况,抑制炎症反应,提高患者满意度。