根面过敏牙髓中P物质分布的免疫组化研究

目的：研究神经肽SP在根面过敏发病中的意义。方法：15只因牙周病拔除的离3体牙，另取整畸拔除牙5只。按ABC法行免疫组织化学染色。结果：在各标本牙髓中均可见SP阳性神经纤维的存在。在正常和根面过敏患牙在成牙本质细胞层下形成神经丛。SP阳性神经在牙髓毛细管周围，少数纤维穿过本质细胞层进入前期牙本质和牙本质小管。结论：通过对严重牙周病根面过敏牙牙髓神经肽P物质的分布观察，提示神经肽在其发病中起重要作用。     

人前磨牙牙髓牙本质复合体中CGRP阳性神经纤维的研究

目的 :研究CGRP在牙髓牙本质复合体中的表达 ,探讨牙痛、牙过敏机理。方法 :收集人前磨牙 ,石蜡包埋切片 ,免疫组化 ,图象定量分析。结果 :CGRP阳性神经纤维分布于牙髓、前期牙本质 ,但不到达成熟牙本质 ,部分分支围绕血管 ,部分分支终止于牙髓基质 ,或成牙本质细胞层 ,或前期牙本质。CGRP阳性神经纤维在冠髓的积分光密度为 12 .39± 1.6 6 ,体密度为 0 .0 182± 0 .0 10 6 ,线密度为 0 .0 0 46± 0 .0 0 2 6 ,在冠部前期牙本质的积分光密度为13 .0 7± 1.74,线段长度为 (19.42± 8.43)mm。结论 :CGRP阳性神经纤维分布于牙髓、前期牙本质 ,未达成熟牙本质 ,牙外因素引起的牙痛可能与间接刺激神经有关 ,牙内因素引起的牙痛可能与直接刺激神经有关。     

碱性成纤维细胞生长因子及其受体在人牙髓中的表达

目的:探讨碱性成纤维细胞生长因子及其受体在人牙髓中表达和意义。方法:用免疫组化方法检测碱性成纤维细胞生长因子及其受体在人牙髓中的表达。结果:碱性成纤维细胞生长因子在成牙本质细胞层强阳性表达, 在牙髓其它细胞和血管内皮细胞阳性表达;碱性成纤维细胞生长因子受体在成牙本质细胞层弱阳性表达,牙髓其它细胞为阴性。结论:碱性成纤维细胞生长因子及其受体在反应性及修复性牙本质形成过程中可能起重要作用。     

Notch 1信号蛋白在早期牙髓损伤修复中表达的免疫组化研究

目的 :通过建立大鼠牙髓损伤动物模型 ,观察Notch1信号蛋白在牙髓损伤修复过程中的表达。方法 :在大鼠第一磨牙牙合面开髓 ,分别对损伤后 2h、12h、2 4h、3d、7d及正常大鼠牙髓标本进行HE染色、免疫组化染色 ,检测各组标本中Notch1信号的表达。结果 :Notch1信号蛋白在正常成年大鼠牙髓组织中无表达 ,在牙髓损伤后表达上调。牙髓损伤 12h ,Notch1在成牙本质细胞层、部分牙髓细胞间质中呈弱阳性表达。损伤后 1～ 3d ,Notch1在成牙本质细胞层、部分牙髓细胞间质及接近损伤部位的牙髓细胞中呈阳性着色。损伤后 7d ,Notch1的表达位于成牙本质细胞层和穿髓孔下方的细胞增殖层。结论 :Notch1信号蛋白在大鼠牙髓损伤后早期阶段表达逐渐上调 ,随后在成牙本质细胞区及富细胞区牙髓细胞中表达增强 ,并沉积于穿髓点附近的细胞增殖层。提示它可能在牙髓损伤的早期自身修复和牙本质矿化中起作用     

转化生长因子-β受体在人牙髓中的表达和意义

目的：探讨转化生长因子β受体在人牙髓中的表达和牙髓细胞对 Ｔ Ｇ Ｆβ作用的反应机理。方法：用免疫组化方法检测转化生长因子βⅠ型受体（ Ｔβ Ｒ Ｉ）和Ⅱ型受体（ Ｔβ ＲⅡ）在健康及龋坏人牙髓中的表达。结果：转化生长因子βⅠ型受体和Ⅱ型受体在成牙本质细胞层强阳性表达,其中Ⅰ型受体较Ⅱ型受体表达量多,两种受体在成牙本质细胞层下方的富细胞区及中心部牙髓有表达或弱表达,龋坏牙髓与正常牙髓有相同的反应模式。结论：转化生长因子βⅠ型和Ⅱ型受体在健康及龋坏人牙成牙本质细胞及牙髓其它细胞皆有表达,提示成牙本质细胞及牙髓其它细胞在牙髓损伤修复过程中具有重要作用。     

全冠修复牙体预备后牙髓的组织学研究

全冠修复过程中保护牙髓组织的健康是影响修复成功的重要因素之一,通过组织切片,观察４０颗因正畸需要拔除的健康活髓牙,经全冠牙体预备后即时和截暂冠后１,２周的牙髓组织学反应。结果表明：在水雾冷却情况下采用涡轮机进行金瓷全冠牙体预备,牙髓组织改变主要是成牙本质细胞层的乱及局部的出血,充血,备牙后立即给予氧化锌丁香占固剂固暂冠修复,２周后牙髓组织逐渐恢复正常。     

凝血酶受体在人牙髓组织和细胞中表达的免疫组化研究

目的：探讨凝血酶受体在人正常、炎症牙髓组织及体外培养的牙髓成纤维细胞中的表达及其意义。方法：体外培养人牙贿成纤维细胞,收集正常和炎症牙髓组织,采用免疫组织化学方法观察凝血酶受体在牙髓组织和细胞中的表达和分布。结果：体外培养的牙髓成纤维细胞可见受体强阳性表达,正常及炎症牙髓组织中成牙本质细胞层、牙髓细胞、血管内皮细胞均呈广泛的阳性表达,炎症区淋巴细胞、单核细胞、中性粒细胞染色为强阳性。结论：人牙髓组     

S—100蛋白和胶质酸性蛋白在人牙髓组织中表达的研究

目的：观察Ｓ－１００蛋白和胶质酸性蛋白（ＧＡＦＰ）的阳染神经纤维在人第三磨牙的分布。方法：免疫组化染色。结果：Ｓ－１００蛋白的阳性神经纤维广泛分布于牙髓组织，在牙髓中央区其表现为神经束，或环绕于血管壁，在牙髓的周边形成神经网，少许神经末稍进入成牙本质细胞层或前期牙本质。在龋坏牙本质下的成牙本质细胞下层有较多的神经分布。ＧＡＦＰ的阳性纤维分布类似于Ｓ－１００蛋白阳性纤维。结论：Ｓ－１００蛋白和ＧＡＦＰ阳染可显示人牙髓神经纤维支配。     

早期牙髓损伤修复中牙本质涎磷蛋白表达的免疫组化研究

目的：衬步探讨牙本质涎磷蛋白（dentin sialophosphoprotein,DSPP)在早期早贿损伤修复中的作用。方法：制备大鼠牙髓损伤模型,分别对损伤后6h,12h,1d,2d,3d,7d及正常大鼠牙髓标本进行HE和免疫组织化学染色,检测各实验组标本中DSPP的表达。结果：正常大鼠牙髓中仅在成牙本质细胞层有DSPP的阳性着色;牙髓损伤后6h,12h,DSPP在成牙本质细胞层的染色明显减弱;损伤后1-3d,梁色较正常牙增强。此时,牙尖及富细胞区的牙髓细胞也有了性着色;损伤后7d,染色与正常对照无明显差异。结论：DSPP在牙髓损伤的早期阶段表达下调;随后在成牙本质细胞及富细胞区牙髓细胞中表达增强;7d时表达趋于正常。提示：它可能在牙髓损伤早期的自身修复中起作用。     

热休克蛋白70在人正常牙和龋坏牙牙髓中的免疫定位

目的：观察热休克蛋白７０（ｈｅａｔｓｈｏｃｋ ｐｒｏｔｅｉｎ ７０ ,ＨＳＰ７０）在人正常和龋坏牙牙髓组织中免疫定位,并通过对比研究,检测ＨＳＰ７０ 的分布变化。方法：选取人正常牙、浅龋牙和深龋牙的组织切片标本进行免疫组织化学染色,并通过计算机图像分析对比３ 种牙髓中ＨＳＰ７０ 量的不同。结果：ＨＳＰ７０ 于３ 组牙髓组织中普遍表达,分布于成牙本质细胞及细胞突、牙髓成纤维细胞、血管内皮细胞及管壁平滑肌细胞中。牙髓神经阴性。深龋组成牙本质细胞或成牙本质细胞样细胞中含量显著增加（ Ｐ＜ ０．０５） 。浅龋组观察到阳性细胞核数目增加。结论：提示ＨＳＰ７０ 维持成牙本质细胞、牙髓细胞功能,参与牙髓组织的自身修复。     

Nd:YAG激光在修复楔状缺损中的应用

目的 临床观察激光在治疗牙体楔状缺损中的作用。方法 牙体楔状缺损伴发牙本质过敏的患牙80颗,分2组。A组:激光脱敏+光固化修复,B组:光固化修复。结果2组即刻有效率分别为95％、75％,两组间有显著性差异（P<0.01）;1年后复查光固化复合树脂脱落率分别为2.5％、15％。失败率分别为7.5％、30％。两组间仍有显著性差异（P<0.01）。结论激光脱敏+光固化治疗是修复牙体楔状缺损伴牙本质过敏症安全、有效的方法。     

Dentine structure and mineralization in hypocalcified amelogenesis imperfecta: a quantitative X-ray histochemical study

OBJECTIVE: This study was undertaken in order to establish the structural and mineralization pattern of the response of dentine to alterations in enamel in hypocalcified amelogenesis imperfecta (AI). DESIGN: The images and data obtained with scanning electron microscopy and electron probe X-ray microanalysis in enamel and dentine specimens from control and affected teeth were compared in this study. PATIENTS AND METHODS: We compared 46 fragments of permanent teeth from patients with clinically diagnosed hypocalcified AI and 20 normal permanent teeth. All specimens were prepared for electron probe X-ray microanalysis. RESULTS: Dentine is characterized by thickening of the peritubular dentine and partial obliteration of the dentinal tubules that does not give rise to a compact sclerotic cast. In dentine, calcium levels were significantly higher in teeth with clinically hypocalcified AI in relation with control teeth (P < 0.001). CONCLUSIONS: Dentine is affected in hypocalcified AI increasing mineralization (narrower tubules and higher content of calcium) in response to enamel disorder.     

Clinical, histological and microbiological study of hand-excavated carious dentine in extracted permanent teeth.

Changes in cultivable flora in dentine samples collected before and after hand excavation were examined in association with clinical status of the cavity surface, light microscopy and scanning electron microscopy (SEM). Thirty-five extracted permanent molar teeth with an occlusal caries lesion were excavated with hand instruments according to the atraumatic restorative treatment (ART) approach. Excavation pressure, dentine colour and consistency were recorded at the dentine-enamel junction (DEJ) prior to carious dentine removal and at the cavity floor after the final excavation; a microbiological sample of dentine was taken at both stages. Twelve restored teeth; six with positive and six with negative bacterial growth on the second sample, were selected for light microscopy and SEM. The hand-excavation removed tooth structure was soft, irreversibly damaged, dark and highly infected. Hand excavation reached dentine of increased hardness with a more normal colour to provide a sound structural base for restoration. Light and SEM examination of the cavity floor showed infected dentinal tubules in all 12 teeth examined. Linear logistic analysis showed a statistical association between light-yellow dentine on the cavity floor and an absence of bacterial growth (P = 0.006). This short-term in vitro study showed that caries-producing bacteria remained in dentine close to the cavity floor in 26/35 teeth despite clinical observations that indicated a suitably prepared cavity floor.     

Age-related changes in hardness and modulus of elasticity of dentine

OBJECTIVES: Little knowledge has been clarified about the relationship between the morphological and physical changes of dentine during aging. The purpose of this study was to clarify the modulus of elasticity and hardness related to the morphological changes of dentine by aging using a transmitted light microscope (TLM) and a nano-hardness tester (NHT). METHODS: Aged human molars and young third molars were used. The dentine morphology was observed under a TLM. The hardness and Young's modulus of elasticity related to the morphologic study were evaluated with an NHT. RESULTS: The thickness of mantle dentine and globular dentine of aged teeth were less than that of young teeth. Transparent dentine was observed only underneath the attrition of young teeth. Reactionary tertiary dentine formed and a "dark zone" was found at the junction between physiologic secondary and reactionary dentine only in aged teeth. At the mantle dentine, hardness and modulus of elasticity of aged dentine were higher than those of young dentine. The reactionary dentine in aged teeth and newly developed secondary dentine in young teeth demonstrated lower modulus of elasticity and hardness than those of other circumpulpal dentine. Relatively low modulus of elasticity and hardness were observed at the zone between secondary and reactionary dentine. CONCLUSIONS: Changes in dentine due to aging resulted in transformation of morphological features causing changes to their hardness and modulus of elasticity at the explicit areas such as the increase of hardness and modulus of elasticity at mantle dentin and the reduction of these properties at the "dark zone" that found in aged teeth.     

An in vitro investigation into the effects of retained coronal dentine on the strength of a tooth restored with a cemented post and partial core restoration

AIM: This study aimed to examine the fracture resistance of teeth restored with cast post and partial cores supported by different heights of coronal tooth structure. METHODOLOGY: Four specimen groups were prepared. Group A was the control and consisted of 10 single-rooted teeth restored with post and cores cemented in dowel channels with no retained coronal dentine.The test groups, B, C and D differed in the amount of retained buccal coronal dentine having 3, 4 and 5 mm, respectively. All groups were tested to failure using an Instron Universal Testing Machine, Model 1195. The mode of failure for representative specimens for each group was recorded photographically. RESULTS: Specimens in group B where the remaining dentine core was 3 mm in height fractured at a higher force than specimens in the control group (P = 0.0239). There were no statistically significant differences in the forces required to fracture teeth with retained buccal coronal dentine cores of 4 and 5 mm when compared to the control. There was no statistically significant difference between forces required to fracture groups B and C or groups B and D. CONCLUSION: In this in vitro study, 3 mm of retained coronal buccal dentine improved fracture resistance of teeth restored with partial post and cores when compared to teeth without retained coronal dentine.     

Morphological characterization and permeability of attrited human dentine

OBJECTIVE: Dentine is a vital tissue that can be changed by physiological and pathological condition. The purpose of this study was to clarify the morphology and permeability of dentine that changed by wearing process. METHODS: Twenty extracted human molars with enamel attrition and dentine was exposed and 20 intact human extracted third molars that had not reached occlusion were used. Ten teeth per each group were observed under light microscope (LM) and transmission electron microscope (TEM). Remaining 10 teeth per each group were subjected for evaluation of dentine permeability. RESULTS: Under LM, the transparent dentine and reactionary dentine were found in the attrition group but were not found in the group unaffected by attrition. When the transparent dentine were examined under the TEM, it was found that dentinal tubules were partially or completely occluded by growth of peritubular dentine or by precipitation of needle-like or rhombohedral crystals in transparent dentine. In reactionary dentine, tubular dentine structures that were comparable to those in secondary physiologic dentine were observed whereas atubular dentine demonstrated occlusion of tubules by high mineral substances or by peritubular dentine under the TEM. Permeability of dentine from worn teeth was less than those from unoccluded teeth significantly. CONCLUSION: Change in dentine by wear resulted in the formation of reactionary dentine and transparent dentine that illustrated various types and degrees of tubular occlusion. These decrease the dentine permeability.     

Determination of endotoxins in caries: association with pulpal pain

AIM: The aims of this study were: (i) to determine the presence or absence of endotoxins in the superficial and deep layers of carious lesions of symptomatic and asymptomatic teeth with vital pulps; (ii) to quantify the amount of endotoxin present; and (iii) to associate the presence of endotoxins with the acute pulpal pain derived from the irreversible pulpitis. METHODOLOGY: Two specimens of carious dentine were taken under aseptic conditions from symptomatic teeth with irreversible pulpitis (n = 9) and asymptomatic teeth with reversible pulpitis (n = 11). The first specimen was taken from a layer of superficial caries and the second from a deeper one. Sound dentine was also collected from intact teeth without restoration and used as a noncarious control group (n = 4). During the patient sampling procedure an effort was made to collect an equal quantity of caries and sound dentine in all cases (approximately 6 mg). The extraction of endotoxins was performed using the Phenol-water method. The assay and quantitative determination of endotoxins was performed by the Quantitative Chromogenic test using Limulus Lysate. Data were analysed statistically using either independent or paired t-tests. RESULTS: The results indicated that endotoxins were present in the superficial and deep layers of caries of all symptomatic teeth with irreversible pulpitis (0.15078 and 0.12111 ng mL-1, respectively), with significantly greater amount (P < 0.01) in the superficial compared to the deep layer. Endotoxins were found in superficial and deep layer of caries of all asymptomatic teeth with reversible pulpitis (0.12091 and 0.07163 ng mL-1, respectively), with significantly greater amounts (P < 0.001) in the superficial compared to the deep layer. The results also demonstrated that significantly greater concentrations (P < 0.005) of endotoxins were present in the superficial carious layer of symptomatic compared with asymptomatic teeth (0.15078 and 0.12091 ng mL-1, respectively). Likewise, significantly greater amounts (P < 0.001) of endotoxins were present in the deep carious layer of symptomatic compared with asymptomatic teeth (0.12111 and 0.07163 ng mL-1, respectively). In sound dentine no endotoxins were detected. CONCLUSIONS: This study demonstrates that endotoxins are present in carious lesions of symptomatic and asymptomatic teeth. The amount of endotoxin was significantly greater in the superficial compared to the deep layer of carious dentine. More endotoxins are present in caries of painful teeth compared with those without symptoms.     

Morphometric computerized analysis on the dentinal tubules and the collagen fibers in the dentine of human permanent teeth.

A morphometric analysis has been performed on important components of human dentine using an image computerized analyzer. The dentinal tubule diameter and their area percentage were calculated. Moreover the area percentage of the collagen fibers in the dentinal matrix was measured. These parameters have been evaluated in different areas of the coronal and the radicular dentine in permanent teeth. Measurements have been performed on undecalcified and decalcified teeth and on teeth treated with enzymatic digestion to remove the organic non collagen matrix and to evidentiate the collagen fiber network. The values obtained in different areas of the tooth and in samples submitted to different treatments were evaluated by statistical analysis. Dentinal tubule diameter and area percentage significatively decrease from the inner to the peripheral dentine both in the undecalcified teeth as in the decalcified ones and in the samples undergone to enzymatic digestion. The collagen fiber percentage in the organic matrix is significatively lower in the mantle dentine.     

An ex vivo study of the effects of retained coronal dentine on the strength of teeth restored with composite core and different post and core systems

AIM: To investigate the fracture resistance and fracture patterns of teeth restored with composite cores supported by different pre-fabricated post systems and different heights of remaining coronal dentine. METHODOLOGY: Four groups of 30 single rooted teeth were used. Each group was divided into three subgroups of 10 teeth each and restored with carbon fibre, glass fibre, or Radix titanium posts luted with dual cure resin cement. The control group A had no retained coronal dentine. Groups B, C and D had 2, 3 and 4 mm of retained buccal and lingual coronal dentine, respectively. Teeth were tested to failure using an Instron Universal Testing Machine. Subsequently, the fracture mode of specimens was recorded. RESULTS: Teeth with retained dentine were more resistant to fracture (P = 0.001). Tooth fracture resistance was not significantly different between groups B, C and D. Within group A, titanium posts were associated with higher fracture resistance than fibre posts. Within the other groups, tooth fracture resistance was not related to post material. Within groups C and D, fracture resistance of teeth restored with carbon fibre posts was significantly higher than those restored with glass fibre posts. The dominant fracture mode in group A was core and vertical oblique root fracture whilst a combination of core, coronal dentine and root fracture occurred in the other groups. CONCLUSIONS: Fracture resistance of teeth increased with the presence of retained coronal dentine. The use of glass and carbon fibre posts did not improve the fracture resistance or the fracture pattern of teeth when compared with metal titanium posts regardless of the presence of retained coronal dentine. The dominant fracture pattern of teeth was not related to the amount of retained dentine if it was >2 mm high.     

Nd:YAG激光辅助复合体治疗根面龋的即刻脱敏作用及临床效果观察

目的：观察Nd：YAG激光辅助Dyract复合体治疗老年人根面龋的即刻脱敏效果及充填修复效果。方法：选择66例老年忠者的162颗临床诊断为根面龋并有牙本质过敏症的患牙，随机分成2组，实验组用脉冲Nd：YAG激光照射窝洞后，用光固化Dyract复合体充填修复，对照组用光固化Dyract复合体直接充填修复。观察2组的即刻脱敏效果及半年、一年的临床充填修复效果，井进行统计学分析。结果：实验组即刻脱敏显效率为90．2％，半年成功率为96．3％，一年成功宰为92．7％；对照组的即刻脱敏显效率、半年成功率、一年成功率分别为76．3％、92．7％，82．5％。2组的即刻脱敏显效率和一年成功率差异有统计学意义。结论：选择合适参数谩置，用脉冲Nd：YAG激光辅助Dyract复合体治疗老年根龋，能减轻术后牙本质敏感症状和提高充填修复的效果，具有临床使用价值。