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目的    研究核因子κB受体活化因子配基（RANKL）在人继承恒牙缺失滞留乳牙及乳牙根生理性吸收不同时期的表达。方法    选取2010年6-12月沈阳市口腔医院正畸科及儿童牙病科10～15岁患者因治疗需要拔除的乳牙18颗,按牙根吸收长度不同分为牙根吸收早、中、晚期（早期组、中期组、晚期组）,各6颗。同时选取无恒牙胚滞留乳牙（滞留组）和正畸拔除的正常恒牙（对照组）各6颗。采用免疫组化方法检测RANKL蛋白的表达,并测定累积光密度值。结果    牙髓成纤维细胞：对照组RANKL累积光密度值明显低于其余组（均P < 0.01）;早期组、中期组明显低于晚期组（均P < 0.01）。成牙本质细胞：对照组RANKL累积光密度值亦明显低于其余组（均P < 0.01）;早期组、中期组、晚期组三者间差异均有统计学意义（P < 0.01）。破牙细胞：对照组未见破牙细胞;早期组、中期组与晚期组比较差异有统计学意义（P < 0.01）。结论    RANKL是引起乳牙牙根缓慢吸收的因素之一。     

A transmission electron microscope study of fibroblast changes in human deciduous tooth pulp

The coronal pulps of four primary canines, free from radicular resorption, and of three primary teeth, with roots entirely resorbed, were prepared for electron microscopy. Mature fibroblasts, similar to those reported in the pulps of permanent teeth, were present in the pulps of the clinically mature teeth. Regression of fibroblasts, evident in the pulps of deciduous teeth at the root resorption stage, was characterized by cytoplasmic changes, modifications in the cytoskeleton and dissociation of cells and fibrils. Deciduous teeth might provide a model for studying pulp fibroblast ageing.     

RANKL在人乳牙根生理性吸收过程中的表达

目的:探讨核因子κB受体活化剂配体RANKL在人乳牙根生理性吸收过程中的表达及作用。方法:运用免疫组织化学的方法检测人乳牙根生理性吸收过程中RANKL蛋白的表达。结果:乳牙的破牙细胞、牙髓成纤维细胞及成牙本质细胞胞浆中RANKL免疫组化染色阳性,且表达高于恒牙组,差异有统计学意义(P<0.05),乳牙牙周韧带成纤维细胞RANKL染色结果与恒牙组相比较差异无统计学意义(P>0.05)。结论:RANKL在人乳牙牙根生理性吸收过程中有表达,其可能对乳恒牙替换起到一定的促进作用。     

间歇性完全鼻阻塞对幼年大鼠髁突软骨细胞凋亡影响的研究

目的 研究幼年大鼠在双侧间歇性鼻阻塞情况下双侧髁突软骨细胞的凋亡情况,来尝试探讨间歇性鼻阻塞对张口呼吸儿童髁突软骨发育的影响。方法 将20只4周龄大鼠（Sprague-Dawley rat,SD rat）分为2组,A组：双侧鼻阻塞组,常氧条件下鼻孔双侧阻塞8 h（8.00AM-16.00PM）,持续35 d;B组：对照组 ,常氧条件下饲养 。2组给予同样的饮食以及饮水,然后分别取出双侧髁突,用甲醛保存做成石蜡切片,同时进行caspase-3以及Bcl-2,Bax蛋白免疫组化染色。以观察在双侧鼻阻塞对髁突前斜面中上部软骨细胞增殖以及凋亡的影响,以及双侧间歇性鼻阻塞情况下Bcl-2基因家族的调控机制以及与下颌骨生长发育的关系。结果 在间歇性双侧完全鼻阻塞情况下,SD幼年大鼠双侧髁突软骨细胞凋亡较对照组明显增加。结论 双侧鼻阻塞的未成年大鼠前斜面中上部髁突细胞Bcl-2蛋白以及Bax蛋白,Caspase-3, Bax蛋白表达均较对照组增加,Bcl-2蛋白表达数量实验组较对照组表达减少,髁突软骨细胞凋亡数量较对照组明显增加。     

C型利钠利尿肽在人乳牙根生理性吸收过程中的表达

目的：探讨C型利钠利尿肽（C-type natriuretic peptide,CNP）在人乳牙根生理性吸收过程中的表达及作用。方法：运用免疫组织化学方法检测人乳牙根生理性吸收过程中CNP蛋白的表达。结果：乳牙的破牙细胞、牙髓成纤维细胞及成牙本质细胞胞浆中CNP免疫组化染色阳性,且表达高于恒牙组,差异有统计学意义（P〈0.05）,乳牙牙周韧带成纤维细胞CNP染色亦阳性。结论：CNP在人乳牙牙根生理性吸收过程中有表达,可能对乳恒牙替换起到一定的促进作用。     

核转录因子Kappa B在犬乳恒牙替换过程中的表达

目的：观察犬乳恒牙替换过程中核转录因子Kappa B的表达，探讨其在牙齿替换中的作用。方法：用免疫组织化学方法检测NF—kB在犬乳恒牙替换过程中的表达。结果：NF—kB在幼犬替牙期的恒牙胚上方骨组织中的破骨细胞以及乳牙根面和牙髓腔内的破牙细胞中均有阳性信号表达。结论：NF—kB可能参与了犬乳恒牙替换过程中的牙齿的萌出过程。     

Primary teeth show less protecting factors against root resorption

International Journal of Paediatric Dentistry 2011; Background. Physiological root resorption differentiates primary from permanent teeth. The understanding of what protects and regulates root resorption might help to develop therapies to its control. Aim. To verify the presence and distribution of ECRM and the expression of CK14, OPG, TRAP and COX‐2 in the periodontal ligament (PDL) of human primary and permanent teeth. Design. Eight primary teeth undergoing physiological or pathological root resorption and 4 permanent teeth were immunohistochemically processed for CK14, TRAP, COX‐2 and OPG expression. Results. PDL from primary and permanent teeth showed similar morphological features; however, fewer ECRM clusters and higher immunoreactivity to CK14 were found in primary PDL. In permanent teeth, ECRM were distributed along the entire PDL tissue. Howship′s lacunae were found only in primary teeth, associated with the presence of TRAP‐positive cells and increase in COX‐2 expression. OPG expression in primary PDL was detected in nonresorptive cervical areas and in lacunae showing reparative tissue. It was observed higher expression of OPG in all permanent teeth when compared to primary specimens. Conclusions. It may be concluded that PDL from primary teeth shows less ECRM clusters and lower expression of OPG. These features may be associated with lower protection against root resorption in primary teeth.     

A possible association between early apical resorption of primary teeth and ectodermal characteristics of the permanent dentition

The hypothesis of this study is that children with unexpected early apical resorption of the primary teeth are also predisposed to resorption in the permanent dentition. Accordingly, the aim was to perform a longitudinal study focussing on the permanent teeth in children with unexpected early apical resorption in the primary dentition. Panoramic radiographs of 12 children (7 boys and 5 girls) aged 6 years 4 months to 8 years 9 months with unexpected early apical resorption of primary teeth were identified from a dental archive of 588 patients. After written request, follow-up radiographs were obtained (2-15 year interval between early and follow-up radiographs). The radiographs were examined in order to verify the abnormal resorption pattern of the primary teeth and dental deviations in the permanent teeth, known to predispose for root resorption (i.e. invaginations, narrow crowns, abrupt root deflections, slender roots, short roots, taurodontia, agenesis, deviant pattern of eruption). Primary dentition: Two phenotypically different resorption groups were identified: group I, eight patients (resorption of the roots only), and group II, four patients (resorption of root and crown). Permanent dentition: In all 12 children, dental deviations in the permanent dentition were observed. Additionally, idiopathic external apical resorption of the permanent teeth was seen in three children, two of whom had received orthodontic treatment.     

Immunolocalization of bone extracellular matrix proteins (type I collagen,osteonectin and bone sialoprotein) in human dental pulp and cultured pulp cells

AIM: To simultaneously analyse the expression of type I collagen, osteonectin and bone sialoprotein (BSP) in human dental pulp of different ages. METHODOLOGY: Cultured dental pulp fibroblasts (FP1 cell line), pulps from dental germs with incomplete root formation (n = 4) and pulps of erupted teeth with total root formation (n = 4) were used. Bone proteins were searched by immunohistochemistry and immunofluorescence using polyclonal antibodies and compared among the three groups assessed. RESULTS: Immunohistochemistry detected the three proteins in dental pulp tissue, as it labelled extracellular matrix, predentine and odontoblasts. The BSP label was weaker, when compared to both type I collagen and osteonectin. The presence of type I collagen was more evident in pulps from erupted teeth, when compared to germ dental pulps. On the other hand, a strong expression of osteonectin in germ dental pulps was observed. CONCLUSIONS: Regardless of the degree of maturation, dental pulps present type I collagen, osteonectin and BSP in the extracellular matrix (ECM) and in the odontoblastic layer. Thus, the results suggest that these proteins are related to the production and mineralization of dentine.     

Expression of apoptotic and cell proliferation regulatory proteins in actinic cheilitis

BACKGROUND: Actinic cheilitis (AC) is a pre-malignant lesion caused by ultraviolet (UV) radiation. The apoptotic proteins p53, bax, bcl-2, and the proliferation marker Ki-67, are known to play an important role in UV-exposed skin and carcinomas, therefore, these markers were assessed in AC and compared with normal lip and oral mucosa. METHODS: AC (n = 13), normal lip (n = 7) and oral mucosa (n = 6) biopsies were stained immunohistochemically for p53, bax, bcl-2 and Ki-67, to determine their expression and distribution. RESULTS: p53 was over-expressed in AC as compared with normal lip and oral mucosa (P < 0.003). Although bcl-2 expression was higher in AC than in oral mucosa (P < 0.002), it was significantly reduced as compared with normal lip (P < 0.04). Bax expression remained unchanged, and Ki-67 was significantly increased in AC and normal lip as compared with oral mucosa (P < 0.05). CONCLUSION: The results suggest that DNA-damaged cells by UV radiation in AC are eliminated by apoptosis.     

A SCANNING ELECTRON MICROSCOPIC STUDY OF THE PATTERNS OF EXTERNAL ROOT RESORPTION UNDER DIFFERENT CONDITIONS

Objective:

The aim of this study was to examine if there are qualitative differences in the appearance of external root resorption patterns of primary teeth undergoing physiologic resorption and permanent teeth undergoing pathological root resorption in different conditions.

Material and Methods:

A total of 40 teeth undergoing external root resorption in different conditions were divided into 4 groups and prepared for examination under scanning electron microscopy at magnifications ranging from 20x to 1000x. Group I: 10 primary molars exfoliated due to physiologic root resorption; Group II: 10 permanent teeth with periapical granulomas showing signs of resorption; Group III:10 permanent teeth therapeutically extracted during the course of orthodontic therapy with evidence of resorption, and Group IV: 10 permanent teeth associated with odontogenic tumors that showed evidence of resorption.

Results:

In Group I, the primary teeth undergoing resorption showed smooth extensive and predominantly regular areas reflecting the slow ongoing physiologic process. In Group II, the teeth with periapical granulomas showed the resorption was localized to apex with a funnel shaped appearance in most cases. Teeth in Group III, which had been subjected to a short period of light orthodontic force, showed the presence of numerous resorption craters with adjoining areas of cemental repair in some cases. Teeth associated with odontogenic tumors in Group IV showed many variations in the patterns of resorption with extensive loss of root length and a sharp cut appearance of the root in most cases.

Conclusion:

Differences were observed in the patterns of external root resorption among the studied groups of primary and permanent teeth under physiologic and pathological conditions.     

犬乳恒牙替换期VEGF的表达及意义

目的：探讨犬乳恒牙替换过程中破骨细胞内血管内皮生长因子（Vascular endothelial grouth fautor,VEGF）的表达及意义。方法：分别对乳牙期、替牙期、恒牙期本地犬取上、下颌骨,制备石蜡切片,进行HE染色和破骨细胞内VEGF的免疫组化染色,用彩色病理图像分析系统分析各组染色强度灰度值。结果：替牙期犬牙根周围组织破骨细胞VEGF的免疫组化强度明显高于其它两组,且阳性信号出现在破牙细胞中。结论：VEGF在犬乳恒牙替换过程中可能起重要作用。     

Vascular pathways within pulpal tissue of human primary teeth.

The vascular distribution within pulps of human primary teeth has not been as well studied as those within human permanent teeth. Such information is useful to those who diagnose and treat dental conditions in children. The purpose of this study was to determine the architecture of the vascular structures, in contrast to the histological appearances, of noncarious human primary teeth during root completion, root resorption and dental caries attack. Following extraction, primary teeth were perfused with an opaque injection mass and photographed to trace the courses of the arterioles, venules and capillaries within the crowns and roots. The architectural morphology of similar vascular structures in permanent pulps are included to provide a comparative reference. Arterioles entered the apical foramina and traveled throughout the root canal(s) to the pulpal chamber, giving off branches which passed toward the dentinal walls. Within the pulpal chamber, the arterioles passed toward the occlusal and proximal surfaces and arborized profusely to form a subodontoblastic plexus of capillaries. The capillaries lead to larger diameter venules, which exited the pulp through apical foramina. Many unusual vascular pathways existed within the root structure. No communication existed between the pulp chamber and periodontal membrane through the furcation dentin and cementum. Many lateral canals were seen along the root structures.     

核心结合因子a1在犬乳恒牙替换过程中的表达

目的：观察犬乳恒牙替换过程中核心结合因子a1(cbf a1)的表达，探讨其在牙齿替换中的作用。方法：利用免疫组织化学方法检测cbf a1在犬乳恒牙替换过程中的表达。结果：cbf a1在幼犬替牙期的恒牙胚根方及旁侧见成骨细胞染色阳性；在恒牙胚上方骨组织中的破骨细胞以及乳牙根面和牙髓腔内的破牙细胞中均有阳性信号表达。结论：cbf a1可能参与了犬乳恒牙替换过程中牙齿的萌出过程。     

Apoptosis in the human periodontal membrane evaluated in primary and permanent teeth

Abstract

Objective. Recent studies revealed a highly innervated layer in close proximity to the root surface in the periodontal membrane of human teeth. Persistence of the epithelial cells of Malassez along root surfaces without resorption has also been demonstrated. It is hypothesized that resorption is connected to apoptosis of the epithelial cells of Malassez. The purpose of this study is to localize cells undergoing apoptosis in the periodontal membrane of human primary and permanent teeth. Materials and methods. Human primary and permanent teeth were examined immunohistochemically for apoptosis and epithelial cells of Malassez in the periodontal membrane. All teeth examined were extracted in connection with treatment. Results. Apoptosis was seen in close proximity to the root surface and within the epithelial cells of Malassez. This pattern of apoptotis is similar in the periodontal membrane in primary and permanent teeth. Conclusions. The inter-relationship between apoptotis and root resorption cannot be concluded from the present study. Apoptosis seen in close proximity to the root surface presumably corresponds to the highly innervated layer of the periodontal membrane. The function of this layer still needs to be elucidated.     

Caspase家族参与乳牙根吸收牙髓组织细胞凋亡的研究进展

在乳恒牙替换过程中,乳牙牙髓组织逐渐减少,这与牙髓组织发生细胞凋亡有关.天冬氨酸特异性蛋白水解酶(cys-teine-containing aspartate-specific protease,Caspase)在细胞凋亡中发挥重要作用.该文就乳牙生理性根吸收过程中牙髓组织的细胞凋亡情况及Caspase家族在其中发挥的...     

人乳牙根生理性吸收过程中CNP的mRNA表达

目的：研究CNP在人乳牙根生理性吸收过程中的mRNA表达及作用。方法：运用原位杂交方法检测人乳牙根生理性吸收过程中CNP的mRNA表达。结果：生理性吸收期乳牙的破牙细胞、牙髓成纤维细胞及成牙本质细胞CNP表达阳性。结论：人乳牙牙根生理性吸收过程中CNP可能促进破牙细胞的分化和活性，可能对乳恒牙替换起到一定的促进作用。     

犬乳恒牙替换期间活化T细胞核因子NFATc1表达的研究

目的通过观察犬乳恒牙替换过程中活化T细胞核因子（nuclear factor of active T cells,NFAT）NFATc1的表达探讨其在此过程中的作用及意义。方法制备犬乳恒牙替换各阶段乳牙根、牙槽骨、恒牙胚的组织标本切片,用免疫组织化学方法检测NFATc1在犬乳恒牙替换期间的表达。结果NFATcl在破骨细胞、恒牙胚成釉细胞、成牙本质细胞层中表达阳性。结论NFATc1可能参与了犬乳恒牙替换生理过程中乳牙根、牙槽骨的吸收和恒牙胚的发育。