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Tooth Buds (tooth + bud)

Distribution by Scientific Domains

Medical Sciences	85%

Selected Abstracts

Spatiotemporal expression of NGFR during pre-natal human tooth development

ORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 2 2002
KB Becktor
Structured Abstract Authors, Becktor KB, Hansen BF, Nolting D, Kjær I. Objectives, The relation between nerve growth factor receptor (NGFR) in the human pre-natal tooth buds and the dental follicle was investigated. In particular, we sought to determine if there is a specific pattern of p75NGFR expression in developing human tooth buds and their surrounding tissue. Setting and Sample Population, The Department of Orthodontics at Copenhagen University, Denmark. Histological sections from 11 fetuses, aged 11,21 gestational weeks. Method, The sections were studied by conventional immunohistochemistry. Results, Specific spatiotemporal patterns of p75NGFR reactions were observed in the tooth buds and dental follicle: Before matrix production by the ameloblasts, the entire inner enamel epithelium and the entire dental follicle display p75NGFR immunoreactivity; after matrix production is initiated, the immunoreactivity of the matrix producing cells is lost, as is that of the dental follicle adjacent to these matrix-producing cells. Conclusion, A unique spatiotemporal distribution of NGFR in the pre-eruptive human tooth bud was demonstrated. [source]

Fate of developing tooth buds located in relation to mandibular fractures in three infancy cases

DENTAL TRAUMATOLOGY, Issue 4 2010
Kazuhiko Yamamoto
Three infants, 2 girls and a boy, aged from 1 year and 5-months old to 2 years and 6-months old, were treated for dislocated mandibular fracture in the symphyseal region by manual reduction and fixation with a thermoforming splint and circumferential wiring under general anesthesia. Fracture healing was uneventful in all cases. A few years later, no obvious deformity of the jaw or malocclusion was observed; however, malformation of the crown was found in one of the permanent teeth on the fracture line in the first case. In the second case, no abnormality was observed in one of the permanent teeth on the fracture line, but the effect on the other tooth could not be evaluated due to abnormality of the tooth probably not related to the injury. In the third case, root formation was arrested in one of the permanent teeth on the fracture line and the tooth was lost early after eruption. The development of tooth buds on the fracture line is not predictable and therefore, should be monitored by regular follow up. [source]

Genetic disruption of CYP26B1 severely affects development of neural crest derived head structures, but does not compromise hindbrain patterning

DEVELOPMENTAL DYNAMICS, Issue 3 2009
Glenn Maclean
Abstract Cyp26b1 encodes a cytochrome-P450 enzyme that catabolizes retinoic acid (RA), a vitamin A derived signaling molecule. We have examined Cyp26b1,/, mice and report that mutants exhibit numerous abnormalities in cranial neural crest cell derived tissues. At embryonic day (E) 18.5 Cyp26b1,/, animals exhibit a truncated mandible, abnormal tooth buds, reduced ossification of calvaria, and are missing structures of the maxilla and nasal process. Some of these abnormalities may be due to defects in formation of Meckel's cartilage, which is truncated with an unfused distal region at E14.5 in mutant animals. Despite the severe malformations, we did not detect any abnormalities in rhombomere segmentation, or in patterning and migration of anterior hindbrain derived neural crest cells. Abnormal migration of neural crest cells toward the posterior branchial arches was observed, which may underlie defects in larynx and hyoid development. These data suggest different periods of sensitivity of anterior and posterior hindbrain neural crest derivatives to elevated levels of RA in the absence of CYP26B1. Developmental Dynamics 238:732,745, 2009. © 2009 Wiley-Liss, Inc. [source]

Syndecan-1 and Wingless-type protein-1 in human ameloblastomas

JOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 7 2007
P. Leocata
Background:, Aberrant Wingless type 1 glycoprotein (Wnt) pathway in ameloblastomas and a role of syndecan-1 (SDC1) in activating Wnt signalling were perspected. SDC1 shifting from epithelium to stroma was reported in invasive non-odontogenic neoplasms. The aim of this study was to reveal the role of SDC1 and Wnt1 in intraosseous ameloblastomas (IAs). Methods:, SDC1 and Wnt1 expressions were investigated in 29 ameloblastoma subtypes and seven tooth buds. Results:, SDC1 immunostaining strongly depicted stromal cells, extracellular matrix (ECM) and basement membranes of ameloblastomas. It also showed epithelial tumour cells in the acanthomatous and plexiform subtypes, and it often occurred in stellate reticulum cells and basal ameloblasts of tooth buds. Parallel Wnt1 expression occurred in ameloblastomatous epithelial cells, but it was common in basal cells of tooth buds too. Statistically, a significant correlation was found between the percentage of IAs -bearing SDC1-positive stromal cells and ECM and the percentage of IAs -bearing Wnt1-positive epithelial cells. Conclusions:, A role of SDC1 in stromal cells and ECM can be hypothesized as a critical factor for carcinogenesis and local invasiveness of IAs. [source]