Lymphatic vessels of the human dental pulp.

Noncarious teeth obtained from individuals 15 to 50 years of age were used to study the lymphatic drainage of the human pulp. Thick sections (50 to 150 microns) were stained with iron hematoxylin for the demonstration of lymph and blood vessels. Lymph capillaries originated as blind sacs in the odontoblastic layer and in the pulp proper near the pulpo-odontoblastic border. They drained into small thin-walled collecting vessels that were irregular in shape and showed great variability in their drainage patterns. Communications between these vessels were very common. The larger conducting lymphatic vessels accompanied the blood vessels and nerves in their course through the pulp. They could be identified by their thin walls and small size. The large caliber lymphatic vessels contained valves, a structure not present in the veins of the same size. The conducting lymphatic vessels passed through the roots as individual units without draining into a large single vessel. The lymphatic vessels of the human pulp must be considered as a pathway for the removal of excessive tissue fluid in normal and diseased pulps.     

大鼠正常牙髓和炎症牙髓中的细胞凋亡

目的：建立大鼠实验性牙髓炎模型;原位观察大鼠正常牙髓和炎症牙髓中细胞凋亡现象,探讨细胞凋亡在牙髓炎病理变化中的作用。方法：１６只ＳＤ大鼠的磨牙采用内毒素化学诱导法建立牙髓炎模型,分别于１ｄ、３ｄ、５ｄ、７ｄ取材,常规制备石蜡切片,行ＨＥ染色和ＴＵＮＥＬ法检测。结果：正常牙髓中成牙本质细胞和牙髓细胞均发现有凋亡细胞;炎症牙髓中炎细胞聚集区未发现典型的凋亡细胞,而在其周边发现有较典型的凋亡细胞,在其正常组织中也有散在的凋亡细胞存在。结论：正常牙髓和炎症牙髓中存在细胞凋亡,细胞凋亡在牙髓炎的转归和预后方面可能有一定的作用。     

Lipid composition of human dental pulp.

The neutral and phospholipid content and composition was determined. No significant differences were obtained between pulps of adolescents or adults or from those obtained from incisors or molars. The lipid profiles revealed the presence of most of the known neutral and phospholipid families. The ratios of these lipids were similar but not identical to that reported for other animal species.     

Fluorescence of biogenic monoamines in the human dental pulp.

Biogenic monoamines in the adrenergic nerve terminals of the human dental pulp are demonstrated by the fluorescence method of Falck and Owman. Unmyelinated nerve fibers from nerves along alveolar blood vessels may enter the pulp, although pulp nerves are composed largely of myelinated fibers. The existence of a few sympathetic fibers is demonstrated by the fluorescence method, and possible drug effects are considered.     

Intracellular destruction of collagen in the human dental pulp.

Electron microscopy of the coronal portion of a pulp from a human molar tooth undergoing caries revealed fibroblasts containing membrane-bound profiles of collagen fibrils in their cytoplasm. In some instances varicosities containing an electron-dense material were present in the profile. A loss of banding characteristic of the collagen fibril was sometimes noted.     

Expression of macrophage inflammatory protein 3alpha in human inflamed dental pulp tissue

Severe pulpitis resulting from dental caries is characterized by marked inflammatory infiltrate such as lymphocytes. Little is known about the recruitment of these cells into the dental pulp lesions of carious teeth. Macrophage inflammatory protein-3alpha (MIP-3alpha), a CC chemokine attracts CC chemokine receptor 6 (CCR6)-expressing T cells. We examined the distribution of MIP-3alpha-positive and/or CCR6-positive cells in human inflamed and normal dental pulp by immunohistochemistry. MIP-3alpha was observed in all inflamed pulp sections, and was mostly distributed in macrophages that had accumulated in the area adjacent to carious lesions. Furthermore, CCR6 expression was also observed in the infiltrating lymphocytes. In contrast, MIP-3alpha and CCR6 were rarely detected in normal pulp. These findings suggest that MIP-3alpha plays a role in the advancement of pulpal inflammation via the recruitment of CCR6-expressing lymphocytes.     

Lymphangiogenesis in human dental pulp

AIM: To investigate the impact of inflammation on lymphangiogenesis in human dental pulp. METHODOLOGY: Eleven samples of dental pulp without inflammation and 11 dental pulps with moderate to intense mononuclear cell inflammatory infiltrate associated with dentine caries were selected. The streptavidin-biotin complex stain was used to detect CD31, vascular endothelial growth factor receptor-3 (VEGFR-3) and alpha-smooth muscle actin. The number of lymphatic vessels was obtained by counting the number of vessels positive for CD31 and VEGFR-3 and negative for alpha-smooth muscle actin. RESULTS: The results demonstrated that the mean number (+/-SD) of vessels positive for CD31 and VEGFR-3 (lymphatic vessels) in the group with inflammation (6.09 +/- 1.81) was statistically higher (P = 0.0123) than the mean number in the group without inflammation (3.73 +/- 2.20). CONCLUSION: Increased co-immunostaining of CD31 and VEGF-3 in vessels associated with human dental pulp inflammation occurred, which suggests lymphangiogenesis.     

The hypoxia-dependent angiogenic process in dental pulp

BackgroundIn this review, we analyzed the existing literature to elucidate how the hypoxia-dependent angiogenic processes work in dental pulp. Angiogenesis is an essential biological process in the maturation and homeostasis of teeth. It involves multiple sequential steps such as endothelial cell proliferation and migration, cell-to-cell contact, and tube formation.HighlightClinical implications of understanding the process of angiogenesis include how the mineralization processes of dental pulp occur and how dental pulp maintains its homeostasis, preventing irreversible inflammation or necrosis.ConclusionThe angiogenesis process in dental pulp regulates adequate concentrations of oxygen required for mineralization in root development and defense mechanisms against chronic stimuli.     

An immunohistochemical study of osteoprotegerin in the human dental pulp.

This study investigated the expression of osteoprotegerin (OPG) in healthy and inflamed dental pulps. Histological sections 7 microm thick of 47 teeth, either caries-free or affected by gross caries, were used. Sections were stained with hematoxylin-eosin, and other sections of the same specimen were subjected to the avidin-biotin peroxidase complex immunohistochemical procedure for detection of OPG. The study focused on the coronal pulp that was divided into peripheral and central regions. In the peripheral pulp healthy and inflamed specimens showed high OPG immunoreactivity of the odontoblastic layer. When no inflammation was present in the central pulp OPG immunoreactivity was light. Fibroblasts and endothelial cells showed immunoreactivity ranging from none to intense. When inflammation was present in the central pulp the chronic inflammatory cells showed intense immunoreactivity.     

Effect of bacterial products on inflammatory reactions in the dental pulp

abstract – Culture filtrates (extracellular components) and material obtained from disintegrated cells (intracellular components) of cultured plaque bacteria were studied for their capacity to induce inflammatory reactions in the dental pulp. Class V cavities were prepared on the buccal surface of 94 teeth: 42 test and 52 control teeth in six adult monkeys. Lyophillzed bacterial components were sealed into the test cavities either alone or following an 8-h topical application of a solution of the same components in phosphate-buffered saline (PBS). Culture medium and PBS were applied in two sets of control cavities. A third set was restored with zinc oxide-eugenol cement. The animals were killed 32 h after the initiation of the experiment and the pulps were examined histologically. Teeth treated with extra- and intracellular components from bacteria elicited marked infiltration of neutrophil leukocytes in the area of the pulp subjacent to the cut dentin tubules. Abscess formation was frequently found. The severe reactions which developed were independent of differences between individual animals and differences in thickness of the remaining dentin. The controls showed damage to the odontoblasts but little or no neutrophil infiltration. The findings confirm that products of bacteria applied to exposed dentin initiate inflammatory reactions in the dental pulp.     

Histologic identification of mast cells in human dental pulp.

Previous investigators who attempted to identify mast cells in the dental pulp have used demineralizing or tooth-splitting procedures to obtain their tissue samples. However, Eda and Langeland15 found that the fluorescence of mast cells is destroyed by acid demineralizing agents. On the other hand, tooth splitting may damage the pulp by crushing it with forceps, or cutting and heating it with burs, stones, or discs. In the present study, we used the extirpated pulps from teeth in which endodontic access openings were made by means of high-speed rotary instruments with water spray. Metachromatic staining methods failed to demonstrate mast cells in any of the non-inflamed pulp specimens. Two of the inflamed pulp specimens revealed numerous mast cells which appeared intact and well preserved with no evidence of degranulation. As to the distribution of the mast cells, there was no correlation with the number and types of other inflammatory cells observed. Although several cells present in the specimens examined were suggestive of mast cells, only those cells that revealed definitive metachromasia were included in this study.